BACKGROUND
[0001] The following relates generally to wireless communications, and more specifically
to signaling support and resource mapping for two-step random access.
[0002] Wireless communications systems are widely deployed to provide various types of communication
content such as voice, video, packet data, messaging, broadcast, and so on. These
systems may be capable of supporting communication with multiple users by sharing
the available system resources (e.g., time, frequency, and power). Examples of such
multiple-access systems include fourth generation (4G) systems such as Long Term Evolution
(LTE) systems, LTE-Advanced (LTE-A) systems, or LTE-A Pro systems, and fifth generation
(5G) systems which may be referred to as New Radio (NR) systems. These systems may
employ technologies such as code division multiple access (CDMA), time division multiple
access (TDMA), frequency division multiple access (FDMA), orthogonal frequency division
multiple access (OFDMA), or discrete Fourier transform spread orthogonal frequency
division multiplexing (DFT-S-OFDM). A wireless multiple-access communications system
may include a number of base stations or network access nodes, each simultaneously
supporting communication for multiple communication devices, which may be otherwise
known as user equipment (UE).
[0003] In some cases, a UE may perform a random access (RA) procedure with a base station.
Conventionally, the RA procedure may involve a four-step handshake. For instance,
the UE may send a RA preamble to the base station and the base station may send a
RA response (RAR) back. The UE may then send a scheduled transmission (a connection
request message), and the base station may perform conflict resolution in response,
transmitting a connection setup message. In some cases, performing a two-step handshake
may decrease latency relative to a four-step handshake. An example can be found in
US 2018/070335 A1.
SUMMARY
[0004] The invention is defined in the appended claims.
[0005] The described techniques relate to improved methods, systems, devices, and apparatuses
that support signaling support and resource mapping for two-step random access. Generally,
the described techniques provide for a user equipment (UE) to receive an indication
of a resource configuration for a random access (RA) procedure. The resource configuration
may identify multiple sets of transmission resources corresponding to multiple radio
resource control (RRC) states. The UE may identify an RRC state and may determine
a set of transmission resources based on the indication of the resource configuration
and the identified RRC state. The UE may, additionally or alternatively, determine
the set of transmission resources based on a UE identifier (UE ID) of the UE. The
UE may transmit a first RA procedure message (e.g., a msgA) using the determined transmission
resources. The base station may receive the message and may identify the RRC state
of the UE based on the first message and transmitted indication of the resource configuration.
The base station may transmit a second RA procedure message (e.g., a msgB), which
the UE may receive.
[0006] A method of wireless communication at a UE is described. The method may include receiving,
from a base station, an indication of a resource configuration for a random access
procedure, the resource configuration identifying a set of sets of transmission resources
corresponding to a set of radio resource control states, identifying a radio resource
control state of the UE, determining a set of transmission resources based on the
indication of the resource configuration, a transport format, and the identified radio
resource control state, and transmitting a first message of the random access procedure
to the base station using the determined transmission resources and the transport
format.
[0007] An apparatus for wireless communication at a UE is described. The apparatus may include
a processor, memory in electronic communication with the processor, and instructions
stored in the memory. The instructions may be executable by the processor to cause
the apparatus to receive, from a base station, an indication of a resource configuration
for a random access procedure, the resource configuration identifying a set of sets
of transmission resources corresponding to a set of radio resource control states,
identify a radio resource control state of the UE, determine a set of transmission
resources based on the indication of the resource configuration, a transport format,
and the identified radio resource control state, and transmit a first message of the
random access procedure to the base station using the determined transmission resources
and the transport format.
[0008] Another apparatus for wireless communication at a UE is described. The apparatus
may include means for receiving, from a base station, an indication of a resource
configuration for a random access procedure, the resource configuration identifying
a set of sets of transmission resources corresponding to a set of radio resource control
states, identifying a radio resource control state of the UE, determining a set of
transmission resources based on the indication of the resource configuration, a transport
format, and the identified radio resource control state, and transmitting a first
message of the random access procedure to the base station using the determined transmission
resources and the transport format.
[0009] A non-transitory computer-readable medium storing code for wireless communication
at a UE is described. The code may include instructions executable by a processor
to receive, from a base station, an indication of a resource configuration for a random
access procedure, the resource configuration identifying a set of sets of transmission
resources corresponding to a set of radio resource control states, identify a radio
resource control state of the UE, determine a set of transmission resources based
on the indication of the resource configuration, a transport format, and the identified
radio resource control state, and transmit a first message of the random access procedure
to the base station using the determined transmission resources and the transport
format.
[0010] Some examples of the method, apparatuses, and non-transitory computer-readable medium
described herein may further include operations, features, means, or instructions
for identifying at least one transmission parameter to be used by the UE to transmit
the first message, where the set of transmission resources may be determined based
on the indication of the resource configuration, the transport format, the identified
radio resource control state, and the at least one transmission parameter.
[0011] Some examples of the method, apparatuses, and non-transitory computer-readable medium
described herein may further include operations, features, means, or instructions
for determining a UE identifier of the UE based on the identified radio resource control
state of the UE, where the set of transmission resources may be determined based on
the indication of the resource configuration, the transport format, the identified
radio resource control state, and the identifier of the UE.
[0012] Some examples of the method, apparatuses, and non-transitory computer-readable medium
described herein may further include operations, features, means, or instructions
for determining a UE identifier of the UE based on the identified radio resource control
state of the UE, and monitoring, based on the determined UE identifier, for a second
message of the random access procedure transmitted by the base station in response
to the transmitted first message.
[0013] Some examples of the method, apparatuses, and non-transitory computer-readable medium
described herein may further include operations, features, means, or instructions
for determining a search space for a control region of the second message based on
the identified radio resource control state of the UE, where the monitoring may be
further based on the determined search space.
[0014] Some examples of the method, apparatuses, and non-transitory computer-readable medium
described herein may further include operations, features, means, or instructions
for determining a time duration for at least a portion of the second message based
on the identified radio resource control state of the UE, where the monitoring may
be further based on the determined time duration.
[0015] In some examples of the method, apparatuses, and non-transitory computer-readable
medium described herein, the set of sets of transmission resources include at least
a first set of transmission resources and a second set of transmissions resources,
the first set of transmission resources include a first uplink data portion corresponding
to a first subset of a preamble portion, and the second set of transmission resources
include a second uplink data portion corresponding to a second subset of die preamble
portion.
[0016] In some examples of the method, apparatuses, and non-transitory computer-readable
medium described herein, the first uplink data portion of die first set of transmission
resources and the second uplink data portion of the second set of transmission resources
share a common set of frequency resources.
[0017] In some examples of the method, apparatuses, and non-transitory computer-readable
medium described herein, the first uplink data portion of the first set of transmission
resources and the second uplink data portion of the second set of transmission resources
share a common set of time resources.
[0018] In some examples of the method, apparatuses, and non-transitory computer-readable
medium described herein, the first uplink data portion of the first set of transmission
resources and the second uplink data portion of the second set of transmission resources
share a common set of space resources.
[0019] In some examples of the method, apparatuses, and non-transitory computer-readable
medium described herein, the preamble portion may include operations, features, means,
or instructions for first time resources different from a common set of time resources
shared by the first uplink data portion and the second data uplink portion; or first
frequency resources different from a common set of frequency resources shared by the
first uplink data portion and the second data uplink portion; or first space resources
different from a common set of space resources shared by the first uplink data portion
and the second data uplink portion; or a combination thereof.
[0020] In some examples of the method, apparatuses, and non-transitory computer-readable
medium described herein, the preamble portion shares a common set of time resources,
or a common set of frequency resources, or a common set of space resources, or a combination
thereof, with the first uplink data portion and the second uplink data portion.
[0021] In some examples of the method, apparatuses, and non-transitory computer-readable
medium described herein, identifying the radio resource control state of the UE may
include operations, features, means, or instructions for identifying that the UE may
be operating in one of a radio resource control inactive state, or a radio resource
control connected state, or a radio resource control idle state.
[0022] In some examples of the method, apparatuses, and non-transitory computer-readable
medium described herein, receiving the indication of the resource configuration for
the random access procedure may include operations, features, means, or instructions
for receiving system information, or radio resource control signaling, or a paging
signal, or a combination thereof, including the indication of the resource configuration.
[0023] In some examples of the method, apparatuses, and non-transitory computer-readable
medium described herein, the set of sets of transmission resources include time resources,
or frequency resources, or spatial resources, or a combination thereof.
[0024] In some examples of the method, apparatuses, and non-transitory computer-readable
medium described herein, the random access procedure may be a two-step random access
procedure that may include operations, features, means, or instructions for receiving,
in response to the transmitted first message, the second message of the two-step random
access procedure.
[0025] Some examples of the method, apparatuses, and non-transitory computer-readable medium
described herein may further include operations, features, means, or instructions
for identifying that the UE lacks a valid timing advance value for the random access
procedure, where the first message may be transmitted regardless of the UE lacking
the valid timing advance value.
[0026] A method of wireless communication at a base station is described. The method may
include transmitting, to a UE, an indication of a resource configuration for a random
access procedure, the resource configuration identifying a set of sets of transmission
resources corresponding to a set of radio resource control states, receiving, from
the UE, a first message of die random access procedure, identifying a radio resource
control state of the UE based on the received first message of the random access procedure
and the transmitted indication of the resource configuration, and transmitting, to
the UE based on the identified radio resource control state of the UE, a second message
of the random access procedure in response to the received first message.
[0027] An apparatus for wireless communication at a base station is described. The apparatus
may include a processor, memory in electronic communication with the processor, and
instructions stored in the memory. The instructions may be executable by the processor
to cause the apparatus to transmit, to a UE, an indication of a resource configuration
for a random access procedure, the resource configuration identifying a set of sets
of transmission resources corresponding to a set of radio resource control states,
receive, from the UE, a first message of the random access procedure, identify a radio
resource control state of the UE based on the received first message of the random
access procedure and the transmitted indication of the resource configuration, and
transmit, to the UE based on the identified radio resource control state of the UE,
a second message of the random access procedure in response to the received first
message.
[0028] Another apparatus for wireless communication at a base station is described. The
apparatus may include means for transmitting, to a UE, an indication of a resource
configuration for a random access procedure, the resource configuration identifying
a set of sets of transmission resources corresponding to a set of radio resource control
states, receiving, from the UE, a first message of the random access procedure, identifying
a radio resource control state of the UE based on the received first message of the
random access procedure and the transmitted indication of the resource configuration,
and transmitting, to the UE based on the identified radio resource control state of
the UE, a second message of the random access procedure in response to the received
first message.
[0029] A non-transitory computer-readable medium storing code for wireless communication
at a base station is described. The code may include instructions executable by a
processor to transmit, to a UE, an indication of a resource configuration for a random
access procedure, the resource configuration identifying a set of sets of transmission
resources corresponding to a set of radio resource control states, receive, from the
UE, a first message of the random access procedure, identify a radio resource control
state of the UE based on the received first message of the random access procedure
and the transmitted indication of the resource configuration, and transmit, to the
UE based on the identified radio resource control state of the UE, a second message
of the random access procedure in response to the received first message.
[0030] Some examples of the method, apparatuses, and non-transitory computer-readable medium
described herein may further include operations, features, means, or instructions
for identifying at least one transmission parameter used by the UE to transmit the
first message, where the radio resource control state may be identified based on the
identified at least one transmission parameter.
[0031] Some examples of the method, apparatuses, and non-transitory computer-readable medium
described herein may further include operations, features, means, or instructions
for determining a UE identifier based on the first message, and identifying a first
set of transmission resources of the set of sets of transmission resources for the
second message based on the UE identifier and the identified radio resource control
state.
[0032] In some examples of the method, apparatuses, and non-transitory computer-readable
medium described herein, identifying the radio resource control state may include
operations, features, means, or instructions for identifying that the UE may be operating
in one of a radio resource control inactive state, or a radio resource control connected
state, or an radio resource control idle state.
[0033] In some examples of the method, apparatuses, and non-transitory computer-readable
medium described herein, transmitting the indication of the resource configuration
for the random access procedure may include operations, features, means, or instructions
for transmitting system information, or radio resource control signaling, or a paging
signal, or a combination thereof, including the indication of the resource configuration.
[0034] In some examples of the method, apparatuses, and non-transitory computer-readable
medium described herein, the set of sets of transmission resources include time resources,
or frequency resources, or spatial resources, or a combination thereof.
[0035] In some examples of the method, apparatuses, and non-transitory computer-readable
medium described herein, the random access procedure may be a two-step random access
procedure that includes the first message and the second message.
BRIEF DESCRIPTION OF THE DRAWINGS
[0036]
FIG. 1 illustrates an example of a wireless communications system that supports signaling
support and resource mapping for two-step random access in accordance with aspects
of the present disclosure.
FIG. 2 illustrates an example of a wireless communications system that supports signaling
support and resource mapping for two-step random access in accordance with aspects
of the present disclosure.
FIG. 3 illustrates an example of a transmission chain that supports signaling support
and resource mapping for two-step random access in accordance with aspects of the
present disclosure.
FIGs. 4A, 4B, and 4C illustrate examples of resource mapping schemes that support
signaling support and resource mapping for two-step random access in accordance with
aspects of the present disclosure.
FIG. 5 illustrates an example of a process flow that supports signaling support and
resource mapping for two-step random access in accordance with aspects of the present
disclosure.
FIGs. 6 and 7 show block diagrams of devices that support signaling support and resource
mapping for two-step random access in accordance with aspects of the present disclosure.
FIG. 8 shows a block diagram of a communications manager that supports signaling support
and resource mapping for two-step random access in accordance with aspects of the
present disclosure.
FIG. 9 shows a diagram of a system including a device that supports signaling support
and resource mapping for two-step random access in accordance with aspects of the
present disclosure.
FIGs. 10 and 11 show block diagrams of devices that support signaling support and
resource mapping for two-step random access in accordance with aspects of the present
disclosure.
FIG. 12 shows a block diagram of a communications manager that supports signaling
support and resource mapping for two-step random access in accordance with aspects
of the present disclosure.
FIG. 13 shows a diagram of a system including a device that supports signaling support
and resource mapping for two-step random access in accordance with aspects of the
present disclosure.
FIGs. 14 through 18 show flowcharts illustrating methods that support signaling support
and resource mapping for two-step random access in accordance with aspects of the
present disclosure.
DETAILED DESCRIPTION
[0037] A UE may perform a random access (RA) procedure with a base station involving a two-step
handshake (e.g., as part of a two-step random access channel (RACH) procedure). For
instance, the UE may transmit a first RA procedure message (e.g., a message A (msgA)
transmission), which the base station may receive. The base station may transmit a
second RA procedure message (e.g., a message Σt (msgB) transmission), which the UE
may receive. In some cases, the second RA procedure message may be sent in response
to the base station receiving msgA. The first RA procedure message may include a preamble
and an uplink channel (e.g., a physical uplink shared channel (PUSCH)) and the second
RA procedure message may include a downlink control channel (e.g., a physical downlink
control channel (PDCCH)) and a downlink data channel (e.g., a physical downlink shared
channel (PDSCH)).
[0038] The preamble of the first RA procedure message (e.g., a physical random access control
channel (PRACH) preamble) may be a long sequence preamble or a short sequence preamble.
Long sequence preambles may, for instance, have a longer preamble length and/or cyclic
prefix (CP) length than short sequence preambles. In either case, each preamble may
be associated with a particular set of bandwidths. For instance, long sequence preambles
may be associated with bandwidths of 1.08 megahertz (MHz) or 4.32 MHz, where numerology
may be different from PUSCHs. Short sequence preambles may be associated with 2.16
MHz or 4.32 MHz and may have the same numerology as PUSCHs. Additionally or alternatively,
short sequence preambles may have 12 physical resource blocks (e.g., 12 PRBs) and
may have a subcarrier spacing (SCS) of 15 kHz or 30 kHz (e.g., within FR1).
[0039] In some cases, the bandwidth of the preamble in a first RA procedure message may
be insufficient to be used as a bandwidth of a corresponding PUSCH (e.g., the PUSCH
in the RA procedure message) and/or demodulation reference signal (DMRS). For instance,
a payload size of the PUSCH may be so large that a single PUSCH transmission with
the same or smaller bandwidth as the preamble may span an amount of time greater than
an acceptable threshold. Similarly, the bandwidth of a downlink control channel (e.g.,
PDCCH) may be insufficient to be used as a bandwidth of downlink data channel transmissions
(e.g., PDSCHs).
[0040] In such cases or in other cases, msgA may contain a preamble portion and a payload
portion and may be configured with a different number of physical resources. The entire
pool of preambles may be partitioned into different subsets, and each subset of preambles
may be associated with a specific RRC state and/or pre-configured payload size whose
PUSCH and/or DMRS are mapped to one or more sets of physical resources. For instance,
a first subset of the preamble may be mapped to a first payload resource, a second
subset of a preamble may be mapped to a second payload resource, and a third subset
of a preamble may be mapped to a third payload resource, and so on. The set of resources
to which the subsets of the preamble are mapped may be preconfigured and may be chosen
based on RRC state (e.g., whether the UE is operating in an inactive state such as
RRC_INACTIVE, or a connect state such as RRC_CONNECTED, or an idle state such as RRC_IDLE
state). In one example, each mapped resource for a payload of a msgA may be overlap
in time but may be transmitted on different subchannels or sub-bands. In such cases,
the preamble may be transmitted before the payload or may overlap in time with the
payload but may be disjoint from the mapped resources in frequency. In another example,
each mapped resource for a payload of msgA may overlap in frequency but may be disjoint
from each other in time. In another example, each mapped resource of a payload of
msgA may overlap in frequency and/or time, but may be disjoint in space (e.g., each
mapped resource may be sent over a separate beam). Each mapped resource for a payload
of msgA may be configured for the same or different RRC states and may have the same
or different transport block sizes (TBSs) and/or modulation coding schemes (MCSs)
as other mapped resources.
[0041] In some cases, UEs may be distinguished based on different multiple access (MA) signatures
and/or different UE identifiers (IDs) (e.g., RA radio network temporary ID (RA-RNT1)).
MA signatures may be carried by the preamble, the DMRSs of the mapped resources, a
resource index, or a combination in time, frequency and/or space. A base station may
determine RA-RNTIs for msgB based on RRC state and/or an index of a MA signature of
the first RA procedure message, and may scramble the RA-RNTI with downlink control
information (DCI) of the downlink control channel of the second RA procedure message.
[0042] Aspects of the disclosure are initially described in the context of a wireless communications
system. Aspects of the disclosure are additionally described in the context of an
additional wireless communications system, a transmission chain, resource mapping
schemes, and a process flow. Aspects of the disclosure are further illustrated by
and described with reference to apparatus diagrams, system diagrams, and flowcharts
that relate to signaling support and resource mapping for two-step random access.
[0043] FIG. 1 illustrates an example of a wireless communications system 100 that supports
signaling support and resource mapping for two-step random access in accordance with
aspects of the present disclosure. The wireless communications system 100 includes
base stations 105, UEs 115, and a core network 130. In some examples, the wireless
communications system 100 may be a Long Term Evolution (LTE) network, an LTE-Advanced
(LTE-A) network, an LTE-A Pro network, or a New Radio (NR) network. In some cases,
wireless communications system 100 may support enhanced broadband communications,
ultra-reliable (e.g., mission critical) communications, low latency communications,
or communications with low-cost and low-complexity devices.
[0044] Base stations 105 may wirelessly communicate with UEs 115 via one or more base station
antennas. Base stations 105 described herein may include or may be referred to by
those skilled in the art as a base transceiver station, a radio base station, an access
point, a radio transceiver, a NodeB, an eNodeB (eNB), a next-generation NodeB or giga-NodeB
(either of which may be referred to as a gNB), a Home NodeB, a Home eNodeB, or some
other suitable terminology. Wireless communications system 100 may include base stations
105 of different types (e.g., macro or small cell base stations). The UEs 115 described
herein may be able to communicate with various types of base stations 105 and network
equipment including macro eNBs, small cell eNBs, gNBs, relay base stations, and the
like.
[0045] Each base station 105 may be associated with a particular geographic coverage area
110 in which communications with various UEs 115 is supported. Each base station 105
may provide communication coverage for a respective geographic coverage area 110 via
communication links 125, and communication links 125 between a base station 105 and
a UE 115 may utilize one or more carriers. Communication links 125 shown in wireless
communications system 100 may include uplink transmissions from a UE 115 to a base
station 105, or downlink transmissions from a base station 105 to a UE 115. Downlink
transmissions may also be called forward link transmissions while uplink transmissions
may also be called reverse link transmissions.
[0046] The geographic coverage area 110 for a base station 105 may be divided into sectors
making up a portion of the geographic coverage area 110, and each sector may be associated
with a cell. For example, each base station 105 may provide communication coverage
for a macro cell, a small cell, a hot spot, or other types of cells, or various combinations
thereof. In some examples, a base station 105 may be movable and therefore provide
communication coverage for a moving geographic coverage area 110. In some examples,
different geographic coverage areas 110 associated with different technologies may
overlap, and overlapping geographic coverage areas 110 associated with different technologies
may be supported by the same base station 105 or by different base stations 105. The
wireless communications system 100 may include, for example, a heterogeneous LTE/LTE-A/LTE-A
Pro or NR network in which different types of base stations 105 provide coverage for
various geographic coverage areas 110.
[0047] The term "cell" refers to a logical communication entity used for communication with
a base station 105 (e.g., over a carrier), and may be associated with an identifier
for distinguishing neighboring cells (e.g., a physical cell identifier (PCID), a virtual
cell identifier (VCID)) operating via the same or a different carrier. In some examples,
a carrier may support multiple cells, and different cells may be configured according
to different protocol types (e.g., machine-type communication (MTC), narrowband Intemet-of-Things
(NB-IoT), enhanced mobile broadband (eMBB), or others) that may provide access for
different types of devices. In some cases, the term "cell" may refer to a portion
of a geographic coverage area 110 (e.g., a sector) over which the logical entity operates.
[0048] UEs 115 may be dispersed throughout the wireless communications system 100, and each
UE 115 may be stationary or mobile. A UE 115 may also be referred to as a mobile device,
a wireless device, a remote device, a handheld device, or a subscriber device, or
some other suitable terminology, where the "device" may also be referred to as a unit,
a station, a terminal, or a client. A UE 115 may also be a personal electronic device
such as a cellular phone, a personal digital assistant (PDA), a tablet computer, a
laptop computer, or a personal computer. In some examples, a UE 115 may also refer
to a wireless local loop (WLL) station, an Internet of Things (IoT) device, an Internet
of Everything (loE) device, or an MTC device, or the like, which may be implemented
in various articles such as appliances, vehicles, meters, or the like.
[0049] Some UEs 115, such as MTC or IoT devices, may be low cost or low complexity devices,
and may provide for automated communication between machines (e.g., via Machine-to-Machine
(M2M) communication). M2M communication or MTC may refer to data communication technologies
that allow devices to communicate with one another or a base station 105 without human
intervention. In some examples, M2M communication or MTC may include communications
from devices that integrate sensors or meters to measure or capture information and
relay that information to a central server or application program that can make use
of the information or present the information to humans interacting with the program
or application. Some UEs 115 may be designed to collect information or enable automated
behavior of machines. Examples of applications for MTC devices include smart metering,
inventory monitoring, water level monitoring, equipment monitoring, healthcare monitoring,
wildlife monitoring, weather and geological event monitoring, fleet management and
tracking, remote security sensing, physical access control, and transaction-based
business charging.
[0050] Some UEs 115 may be configured to employ operating modes that reduce power consumption,
such as half-duplex communications (e.g., a mode that supports one-way communication
via transmission or reception, but not transmission and reception simultaneously).
In some examples half-duplex communications may be performed at a reduced peak rate.
Other power conservation techniques for UEs 115 include entering a power saving "deep
sleep" mode when not engaging in active communications, or operating over a limited
bandwidth (e.g., according to narrowband communications). In some cases, UEs 115 may
be designed to support critical functions (e.g., mission critical functions), and
a wireless communications system 100 may be configured to provide ultra-reliable communications
for these functions.
[0051] In some cases, a UE 115 may also be able to communicate directly with other UEs 115
(e.g., using a peer-to-peer (P2P) or device-to-device (D2D) protocol). One or more
of a group of UEs 115 utilizing D2D communications may be within the geographic coverage
area 110 of a base station 105. Other UEs 115 in such a group may be outside the geographic
coverage area 110 of a base station 105, or be otherwise unable to receive transmissions
from abase station 105. In some cases, groups of UEs 115 communicating via D2D communications
may utilize a one-to-many (1:M) system in which each UE 115 transmits to every other
UE 115 in the group. In some cases, a base station 105 facilitates the scheduling
of resources for D2D communications. In other cases, D2D communications are carried
out between UEs 115 without the involvement of a base station 105.
[0052] Base stations 105 may communicate with the core network 130 and with one another.
For example, base stations 105 may interface with the core network 130 through backhaul
links 132 (e.g., via an S1, N2, N3, or other interface). Base stations 105 may communicate
with one another over backhaul links 134 (e.g., via an X2, Xn, or other interface)
either directly (e.g., directly between base stations 105) or indirectly (e.g., via
core network 130).
[0053] The core network 130 may provide user authentication, access authorization, tracking,
Internet Protocol (IP) connectivity, and other access, routing, or mobility functions.
The core network 130 may be an evolved packet core (EPC), which may include at least
one mobility management entity (MME), at least one serving gateway (S-GW), and at
least one Packet Data Network (PDN) gateway (P-GW). The MME may manage non-access
stratum (e.g., control plane) functions such as mobility, authentication, and bearer
management for UEs 115 served by base stations 105 associated with the EPC. User IP
packets may be transferred through the S-GW, which itself may be connected to the
P-GW. The P-GW may provide IP address allocation as well as other functions. The P-GW
may be connected to the network operators IP services. The operators IP services may
include access to the Internet, Intranet(s), an IP Multimedia Subsystem (IMS), or
a Packet-Switched (PS) Streaming Service.
[0054] At least some of the network devices, such as a base station 105, may include subcomponents
such as an access network entity, which may be an example of an access node controller
(ANC). Each access network entity may communicate with UEs 115 through a number of
other access network transmission entities, which may be referred to as a radio head,
a smart radio head, or a transmission/reception point (TRP). In some configurations,
various functions of each access network entity or base station 105 may be distributed
across various network devices (e.g., radio heads and access network controllers)
or consolidated into a single network device (e.g., a base station 105).
[0055] Wireless communications system 100 may operate using one or more frequency bands,
typically in the range of 300 megahertz (MHz) to 300 gigahertz (GHz). Generally, the
region from 300 MHz to 3 GHz is known as the ultra-high frequency (UHF) region or
decimeter band, since the wavelengths range from approximately one decimeter to one
meter in length. UHF waves may be blocked or redirected by buildings and environmental
features. However, the waves may penetrate structures sufficiently for a macro cell
to provide service to UEs 115 located indoors. Transmission of UHF waves may be associated
with smaller antennas and shorter range (e.g., less than 100 km) compared to transmission
using the smaller frequencies and longer waves of the high frequency (HF) or very
high frequency (VHF) portion of the spectrum below 300 MHz.
[0056] Wireless communications system 100 may also operate in a super high frequency (SHF)
region using frequency bands from 3 GHz to 30 GHz, also known as the centimeter band.
The SHF region includes bands such as the 5 GHz industrial, scientific, and medical
(ISM) bands, which may be used opportunistically by devices that may be capable of
tolerating interference from other users.
[0057] Wireless communications system 100 may also operate in an extremely high frequency
(EHF) region of the spectrum (e.g., from 30 GHz to 300 GHz), also known as the millimeter
band. In some examples, wireless communications system 100 may support millimeter
wave (mmW) communications between UEs 115 and base stations 105, and EHF antennas
of the respective devices may be even smaller and more closely spaced than UHF antennas.
In some cases, this may facilitate use of antenna arrays within a UE 115. However,
the propagation of EHF transmissions may be subject to even greater atmospheric attenuation
and shorter range than SHF or UHF transmissions. Techniques disclosed herein may be
employed across transmissions that use one or more different frequency regions, and
designated use of bands across these frequency regions may differ by country or regulating
body.
[0058] In some cases, wireless communications system 100 may utilize both licensed and unlicensed
radio frequency spectrum bands. For example, wireless communications system 100 may
employ License Assisted Access (LAA), LTE-Unlicensed (LTE-U) radio access technology,
or NR technology in an unlicensed band such as the 5 GHz ISM band. When operating
in unlicensed radio frequency spectrum bands, wireless devices such as base stations
105 and UEs 115 may employ listen-before-talk (LBT) procedures to ensure a frequency
channel is clear before transmitting data. In some cases, operations in unlicensed
bands may be based on a carrier aggregation configuration in conjunction with component
carriers operating in a licensed band (e.g., LAA). Operations in unlicensed spectrum
may include downlink transmissions, uplink transmissions, peer-to-peer transmissions,
or a combination of these. Duplexing in unlicensed spectrum may be based on frequency
division duplexing (FDD), time division duplexing (TDD), or a combination of both.
[0059] In some examples, base station 105 or UE 115 may be equipped with multiple antennas,
which may be used to employ techniques such as transmit diversity, receive diversity,
multiple-input multiple-output (MIMO) communications, or beamfonning. For example,
wireless communications system 100 may use a transmission scheme between a transmitting
device (e.g., a base station 105) and a receiving device (e.g., a UE 115), where the
transmitting device is equipped with multiple antennas and the receiving device is
equipped with one or more antennas. MIMO communications may employ multipath signal
propagation to increase the spectral efficiency by transmitting or receiving multiple
signals via different spatial layers, which may be referred to as spatial multiplexing.
The multiple signals may, for example, be transmitted by the transmitting device via
different antennas or different combinations of antennas. Likewise, the multiple signals
may be received by the receiving device via different antennas or different combinations
of antennas. Each of the multiple signals may be referred to as a separate spatial
stream, and may carry bits associated with the same data stream (e.g., the same codeword)
or different data streams. Different spatial layers may be associated with different
antenna ports used for channel measurement and reporting. MIMO techniques include
single-user MIMO (SU-MIMO) where multiple spatial layers are transmitted to the same
receiving device, and multiple-user MIMO (MU-MIMO) where multiple spatial layers are
transmitted to multiple devices.
[0060] Beamforming, which may also be referred to as spatial filtering, directional transmission,
or directional reception, is a signal processing technique that may be used at a transmitting
device or a receiving device (e.g., a base station 105 or a UE 115) to shape or steer
an antenna beam (e.g., a transmit beam or receive beam) along a spatial path between
the transmitting device and the receiving device. Beamforming may be achieved by combining
the signals communicated via antenna elements of an antenna array such that signals
propagating at particular orientations with respect to an antenna array experience
constructive interference while others experience destructive interference. The adjustment
of signals communicated via the antenna elements may include a transmitting device
or a receiving device applying certain amplitude and phase offsets to signals carried
via each of the antenna elements associated with the device. The adjustments associated
with each of the antenna elements may be defined by a beamforming weight set associated
with a particular orientation (e.g., with respect to the antenna array of the transmitting
device or receiving device, or with respect to some other orientation).
[0061] In one example, a base station 105 may use multiple antennas or antenna arrays to
conduct beamforming operations for directional communications with a UE 115. For instance,
some signals (e.g. synchronization signals, reference signals, beam selection signals,
or other control signals) may be transmitted by a base station 105 multiple times
in different directions, which may include a signal being transmitted according to
different beamforming weight sets associated with different directions of transmission.
Transmissions in different beam directions may be used to identify (e.g., by the base
station 105 or a receiving device, such as a UE 115) a beam direction for subsequent
transmission and/or reception by the base station 105.
[0062] Some signals, such as data signals associated with a particular receiving device,
may be transmitted by a base station 105 in a single beam direction (e.g., a direction
associated with the receiving device, such as a UE 115). In some examples, the beam
direction associated with transmissions along a single beam direction may be determined
based at least in in part on a signal that was transmitted in different beam directions.
For example, a UE 115 may receive one or more of the signals transmitted by the base
station 105 in different directions, and the UE 115 may report to the base station
105 an indication of the signal it received with a highest signal quality, or an otherwise
acceptable signal quality. Although these techniques are described with reference
to signals transmitted in one or more directions by a base station 105, a UE 115 may
employ similar techniques for transmitting signals multiple times in different directions
(e.g., for identifying a beam direction for subsequent transmission or reception by
the UE 115), or transmitting a signal in a single direction (e.g., for transmitting
data to a receiving device).
[0063] A receiving device (e.g., a UE 115, which may be an example of a mmW receiving device)
may try multiple receive beams when receiving various signals from the base station
105, such as synchronization signals, reference signals, beam selection signals, or
other control signals. For example, a receiving device may try multiple receive directions
by receiving via different antenna subarrays, by processing received signals according
to different antenna subarrays, by receiving according to different receive beamforming
weight sets applied to signals received at a plurality of antenna elements of an antenna
array, or by processing received signals according to different receive beamforming
weight sets applied to signals received at a plurality of antenna elements of an antenna
array, any of which may be referred to as "listening" according to different receive
beams or receive directions. In some examples a receiving device may use a single
receive beam to receive along a single beam direction (e.g., when receiving a data
signal). The single receive beam may be aligned in a beam direction determined based
at least in part on listening according to different receive beam directions (e.g.,
a beam direction determined to have a highest signal strength, highest signal-to-noise
ratio, or otherwise acceptable signal quality based at least in part on listening
according to multiple beam directions).
[0064] In some cases, the antennas of a base station 105 or UE 115 may be located within
one or more antenna arrays, which may support MIMO operations, or transmit or receive
beamforming. For example, one or more base station antennas or antenna arrays may
be co-located at an antenna assembly, such as an antenna tower. In some cases, antennas
or antenna arrays associated with a base station 105 may be located in diverse geographic
locations. A base station 105 may have an antenna array with a number of rows and
columns of antenna ports that the base station 105 may use to support beamforming
of communications with a UE 115. Likewise, a UE 115 may have one or more antenna arrays
that may support various MIMO or beamforming operations.
[0065] In some cases, wireless communications system 100 may be a packet-based network that
operate according to a layered protocol stack. In the user plane, communications at
the bearer or Packet Data Convergence Protocol (PDCP) layer may be IP-based. A Radio
Link Control (RLC) layer may perform packet segmentation and reassembly to communicate
over logical channels. A Medium Access Control (MAC) layer may perform priority handling
and multiplexing of logical channels into transport channels. The MAC layer may also
use hybrid automatic repeat request (HARQ) to provide retransmission at the MAC layer
to improve link efficiency. In the control plane, the Radio Resource Control (RRC)
protocol layer may provide establishment, configuration, and maintenance of an RRC
connection between a UE 115 and a base station 105 or core network 130 supporting
radio bearers for user plane data. At the Physical layer, transport channels may be
mapped to physical channels.
[0066] In some cases, UEs 115 and base stations 105 may support retransmissions of data
to increase the likelihood that data is received successfully. HARQ feedback is one
technique of increasing the likelihood that data is received correctly over a communication
link 125. HARQ may include a combination of error detection (e.g., using a cyclic
redundancy check (CRC)), forward error correction (FEC), and retransmission (e.g.,
automatic repeat request (ARQ)). HARQ may improve throughput at the MAC layer in poor
radio conditions (e.g., signal-to-noise conditions). In some cases, a wireless device
may support same-slot HARQ feedback, where the device may provide HARQ feedback in
a specific slot for data received in a previous symbol in the slot. In other cases,
the device may provide HARQ feedback in a subsequent slot, or according to some other
time interval.
[0067] Time intervals in LTE or NR may be expressed in multiples of a basic time unit, which
may, for example, refer to a sampling period of T
s = 1/30,720,000 seconds. Time intervals of a communications resource may be organized
according to radio frames each having a duration of 10 milliseconds (ms), where the
frame period may be expressed as Tf = 307,200 T
s. The radio frames may be identified by a system frame number (SFN) ranging from 0
to 1023. Each frame may include 10 subframes numbered from 0 to 9, and each subframe
may have a duration of 1 ms. A subframe may be further divided into 2 slots each having
a duration of 0.5 ms, and each slot may contain 6 or 7 modulation symbol periods (e.g.,
depending on the length of the cyclic prefix prepended to each symbol period). Excluding
the cyclic prefix, each symbol period may contain 2048 sampling periods. In some cases,
a subframe may be the smallest scheduling unit of the wireless communications system
100, and may be referred to as a transmission time interval (TTI). In other cases,
a smallest scheduling unit of the wireless communications system 100 may be shorter
than a subframe or may be dynamically selected (e.g., in bursts of shortened TTIs
(sTTIs) or in selected component carriers using sTTIs).
[0068] In some wireless communications systems, a slot may further be divided into multiple
mini-slots containing one or more symbols. In some instances, a symbol of a mini-slot
or a mini-slot may be the smallest unit of scheduling. Each symbol may vary in duration
depending on the subcarrier spacing or frequency band of operation, for example. Further,
some wireless communications systems may implement slot aggregation in which multiple
slots or mini-slots are aggregated together and used for communication between a UE
115 and a base station 105.
[0069] The term "carrier" refers to a set of radio frequency spectrum resources having a
defined physical layer structure for supporting communications over a communication
link 125. For example, a carrier of a communication link 125 may include a portion
of a radio frequency spectrum band that is operated according to physical layer channels
for a given radio access technology. Each physical layer channel may carry user data,
control information, or other signaling. A carrier may be associated with a pre-defined
frequency channel (e.g., an evolved universal mobile telecommunication system terrestrial
radio access (E-UTRA) absolute radio frequency channel number (EARFCN)), and may be
positioned according to a channel raster for discovery by UEs 115. Carriers may be
downlink or uplink (e.g., in an FDD mode), or be configured to carry downlink and
uplink communications (e.g., in a TDD mode). In some examples, signal waveforms transmitted
over a carrier may be made up of multiple sub-carriers (e.g., using multi-carrier
modulation (MCM) techniques such as orthogonal frequency division multiplexing (OFDM)
or discrete Fourier transform spread OFDM (DFT-S-OFDM)).
[0070] The organizational structure of the carriers may be different for different radio
access technologies (e.g., LTE, LTE-A, LTE-A Pro, NR). For example, communications
over a carrier may be organized according to TTIs or slots, each of which may include
user data as well as control information or signaling to support decoding the user
data. A carrier may also include dedicated acquisition signaling (e.g., synchronization
signals or system information, etc.) and control signaling that coordinates operation
for the carrier. In some examples (e.g., in a carrier aggregation configuration),
a carrier may also have acquisition signaling or control signaling that coordinates
operations for other carriers.
[0071] Physical channels may be multiplexed on a carrier according to various techniques.
A physical control channel and a physical data channel may be multiplexed on a downlink
carrier, for example, using time division multiplexing (TDM) techniques, frequency
division multiplexing (FDM) techniques, or hybrid TDM-FDM techniques. In some examples,
control information transmitted in a physical control channel may be distributed between
different control regions in a cascaded manner (e.g., between a common control region
or common search space and one or more UE-specific control regions or UE-specific
search spaces).
[0072] A carrier may be associated with a particular bandwidth of the radio frequency spectrum,
and in some examples the carrier bandwidth may be referred to as a "system bandwidth"
of the carrier or the wireless communications system 100. For example, the carrier
bandwidth may be one of a number of predetermined bandwidths for carriers of a particular
radio access technology (e.g., 1.4, 3, 5, 10, 15, 20, 40, or 80 MHz). In some examples,
each served UE. 115 may be configured for operating over portions or all of the carrier
bandwidth. In other examples, some UEs 115 may be configured for operation using a
narrowband protocol type that is associated with a predefined portion or range (e.g.,
set of subcarriers or RBs) within a carrier (e.g., "in-band" deployment of a narrowband
protocol type).
[0073] In a system employing MCM techniques, a resource element may consist of one symbol
period (e.g., a duration of one modulation symbol) and one subcarrier, where the symbol
period and subcarrier spacing are inversely related. The number of bits carried by
each resource element may depend on the modulation scheme (e.g., the order of the
modulation scheme). Thus, the more resource elements that a UE 115 receives and the
higher the order of the modulation scheme, the higher the data rate may be for the
UE 115. In MIMO systems, a wireless communications resource may refer to a combination
of a radio frequency spectrum resource, a time resource, and a spatial resource (e.g.,
spatial layers), and the use of multiple spatial layers may further increase the data
rate for communications with a UE 115.
[0074] Devices of the wireless communications system 100 (e.g., base stations 105 or UEs
115) may have a hardware configuration that supports communications over a particular
carrier bandwidth, or may be configurable to support communications over one of a
set of carrier bandwidths. In some examples, the wireless communications system 100
may include base stations 105 and/or UEs 115 that support simultaneous communications
via carriers associated with more than one different carrier bandwidth.
[0075] Wireless communications system 100 may support communication with a UE. 115 on multiple
cells or carriers, a feature which may be referred to as carrier aggregation or multi-carrier
operation. A UE 115 may be configured with multiple downlink component carriers and
one or more uplink component carriers according to a carrier aggregation configuration.
Carrier aggregation may be used with both FDD and TDD component carriers.
[0076] In some cases, wireless communications system 100 may utilize enhanced component
carriers (eCCs). An eCC may be characterized by one or more features including wider
carrier or frequency channel bandwidth, shorter symbol duration, shorter TTI duration,
or modified control channel configuration. In some cases, an eCC may be associated
with a carrier aggregation configuration or a dual connectivity configuration (e.g.,
when multiple serving cells have a suboptimal or non-ideal backhaul link). An eCC
may also be configured for use in unlicensed spectrum or shared spectrum (e.g., where
more than one operator is allowed to use the spectrum). An eCC characterized by wide
carrier bandwidth may include one or more segments that may be utilized by UEs 115
that are not capable of monitoring the whole carrier bandwidth or are otherwise configured
to use a limited carrier bandwidth (e.g., to conserve power).
[0077] In some cases, an eCC may utilize a different symbol duration than other component
carriers, which may include use of a reduced symbol duration as compared with symbol
durations of the other component carriers. A shorter symbol duration may be associated
with increased spacing between adjacent subcarriers. A device, such as a UE 115 or
base station 105, utilizing eCCs may transmit wideband signals (e.g., according to
frequency channel or carrier bandwidths of 20, 40, 60, 80 MHz, etc.) at reduced symbol
durations (e.g., 16.67 microseconds). A TTI in eCC may consist of one or multiple
symbol periods. In some cases, the TTI duration (that is, the number of symbol periods
in a TTI) may be variable.
[0078] Wireless communications system 100 may be an NR system that may utilize any combination
of licensed, shared, and unlicensed spectrum bands, among others. The flexibility
of eCC symbol duration and subcarrier spacing may allow for the use of eCC across
multiple spectrums. In some examples, NR shared spectrum may increase spectrum utilization
and spectral efficiency, specifically through dynamic vertical (e.g., across the frequency
domain) and horizontal (e.g., across the time domain) sharing of resources.
[0079] Two-step random access may involve msgA transmission from a UE 115 to a base station
105 and msgB transmission from the base station 105 to the UE 115. The channel structure
of msgA may include a preamble and a PUSCH and the channel structure of msgB may include
a PDCCH and a PDSCH. According to the methods disclosed herein, two-step random access
may be able to operate regardless of whether the UE 115 has a valid timing advance
(TA) or not. Additionally or alternatively, two-step random access as described herein
may be applicable to any of a range of cell sizes. Additionally or alternatively,
two-step random access as described herein may be applied for any of a range of RRC
states, including inactive, connected, or idle states (e.g., RRC_INACTIVE, RRC_CONNECTED,
or RRC IDLE). It should be noted that the methods described herein may be applied
in one or more of multiple communication scenarios (e.g., massive machine type communication
(mMTC), ultra -reliable low latency communications (URLLC), or enhanced mobile broadband
(eMBB)), and may be compatible with communication in licensed and/or unlicensed spectrum.
For a UE 115 (e.g., a downlink-synchronized UE 115), two-step random access may achieve
better performance, lower latency, and/or lower complexity than 4-step RACK and CP
extension.
[0080] In general, PUSCH transmissions in msgA may be based on a non-orthogonal multiple
access (NOMA) low code rate spreading (LCRS) scheme. Additionally or alternatively,
PUSCH reception in msgA may use a NOMA advanced receiver. A NOMA advanced receiver
may, for instance, be able to receive transmissions from multiple UEs 115 simultaneously.
In general, preamble and/or DMRS sequence may be down-selected from NR PRACH preamble
and DMRS sequences, respectively. Data in PUSCH may be transmitted without a TA and
may facilitate savings in latency and transmit power. In some cases, msgA transmission
may be grant-free (e.g., may be transmitted without first receiving a grant of resources)
and/or contention-based (e.g., may involve determining if other UEs 115 or base stations
105 are transmitting on same time and/or frequency resources). After transmitting
msgA, a UE 115 may monitor the DCI of msgB within a pre-configured search space and
RA response (RAR) window. In general, msgB may carry a PDCCH, which may contain a
DCI, and a PDSCH, which may contain a RAR. DCI may specify the frequency domain resource
allocation of RAR.
[0081] Wireless communications system 100 may support efficient techniques for signaling
support and resource mapping for two-step random access. For instance, a UE 115 may
receive, from a base station 105, an indication of a resource configuration for a
RA procedure, the resource configuration identifying multiple sets of transmission
resources corresponding to a set of RRC states. The UE 115 may identify a RRC state
of the UE 115. The UE 115 may determine a set of transmission resources based on the
indication of the resource configuration and the identified RRC state. The UE 115
may transmit a first message of the RA procedure (e.g., msgA) to the base station
105 using the determined resources. The base station may identify a RRC state of the
UE 115 based on the received first message of the RA procedure and the transmitted
indication of the resource configuration. The base station 105 may transmit, to the
UE 115 based on the identified RRC state of the UE 115, a second message of the random
access procedure (e.g., msgB) in response to the received first message.
[0082] FIG. 2 illustrates an example of a wireless communications system 200 that supports signaling
support and resource mapping for two-step random access in accordance with aspects
of the present disclosure. In some examples, wireless communications system 200 may
implement aspects of wireless communications system 100. For instance, wireless communications
system may include UE 115-a and base station 105-a, which may be examples of a UE
115 and a base station 105 as described with reference to FIG. 1.
[0083] A base station 105-a and a UE 115-a may communicate with each other through downlink
communication link 205 and uplink communication link 210. In one example, base station
105-a and UE 115-a may perform a two-step RA procedure. For instance, UE 115-a may
transmit a msgA 215, which base station 105-a may receive, over downlink communication
link 205. The msgA 215 may include a preamble (e.g., a RACH preamble) and/or a uplink
channel (e.g., a PUSCH). Additionally or alternatively, base station 105-a. may transmit
a msgB 220, which may be received by UE 115-a, over uplink communication link 210.
The msgB 220 may include a downlink control channel (e.g., a PDCCH) and a downlink
data channel (e.g., a PDSCH). The PDCCH may include a DCI, and the PDSCH may include
a RAR window. In some cases, base station 105-a may send msgB 220 in response to receiving
msgA 215.
[0084] Within msgA 215 transmissions, different UEs 115 may be distinguished by their MA
signatures. MA signatures may be carried at least by a combination of preamble (e.g.,
PRACH preamble), DMRS, and/or resource index for msgA 215 in time, frequency, and/or
space (e.g., beams). The configuration may be signaled by a system information block
(SIB), RRC signals, and/or paging signals, and may be respected by UE 115-a and/or
base station 105-a.
[0085] Within msgB 220 transmissions, different UEs 115 may be distinguished by their UE
IDs. For instance, the UE ID associated with the msgB transmission may be an RA-RNTI
for two-step random access that has a UE 115 or MA signature index which has successfully
been decoded and may be based on an RRC state detected by base station 105-a. Payload
bits of DCI associated with msgB 220 may be scrambled with RA-RNTI. The scrambling
code generation may be based on preconfigured polynomials or other functions (e.g.,
mathematical functions). The configuration of search space and/or RAR window within
msgB 220 may be chosen as a function of RRC state. Such configurations may be signaled
by SIB, RRC, and/or paging signals, and may be respected by UE 115-a and/or base station
105-a.
[0086] FIG. 3 illustrates an example of a transmission chain 300 that supports signaling support
and resource mapping for two-step random access in accordance with aspects of the
present disclosure. In some examples, transmission chain 300 may implement aspects
of wireless communications systems 100 and 200. For instance, transmission chain 300
may be implemented by a base station 105 and/or a UE 115 as described with reference
to FIGs. 1 and 2.
[0087] Transmission chain 300 may demonstrate how information of a msgA is prepared for
transmission. Information bits 305 may, for instance, be encoded by a low-density
parity-check (LDPC) encoder 310 and may undergo bit scrambling (by bit scrambling
component 315). Bit scrambling may depend on the UE ID (e.g., the RA-RNTI) and/or
MA signature of a UE 115 to transmit the msgA (e.g., output by UE ID component 350),
which may, in turn, depend on the RRC state (e.g., an inactive state, a connected
state, an idle state) of the associated UE 115. The bit scrambled information may
undergo linear modulation (e.g., via linear modulation component 320) and, in some
cases (e.g., if the information is associated with a spreading factor (SF) that is
not equal to 1), the information may undergo UE-specific symbol-level linear spreading
without sparsity, group or cell-specific symbol-level scrambling, and/or single or
multi-branch transmission (e.g., via spreading factor component 325). Regardless of
whether spreading is performed, the information may undergo transform precoding (e.g.,
via transform precoding component 330) and/or resource element (RE) mapping (e.g.,
via RE mapping component 335), and may be transformed through an inverse fast Fourier
transform (IFFT) (e.g., via a IFFT component 340). The transformed information may
be passed through a multiplexer (MUX) 345.
[0088] In some cases, the output of the MUX 345 may be affected by preamble and DMRS mapping
(e.g., via preamble and DMRS mapping component 355). As described herein, a msgA preamble
and/or DMRS (e.g., a DMRS associated with a PUSCH of msgA) may be mapped to a number
of configurations in time, frequency, and/or space (e.g., beams). This configuration
may affect the resources the information output from transmission chain 300 are transmitted
on. The preamble and DMRS mapping may be configurable and may depend on UE ID (e.g.,
RA-RNTT) and/or MA signature (e.g., via UE ID component 350). For instance, a first
configuration may be used if the UE 115 is associated with a first UE ID and a second
configuration may be used if the UE 115 is associated with a second UE ID.
[0089] FIG. 4A illustrates an example of a resource mapping scheme 400 that supports signaling support
and resource mapping for two-step random access in accordance with aspects of the
present disclosure. In some examples, resource mapping scheme 400 may implement aspects
of wireless communications systems 100 and 200. For instance, resource mapping scheme
400 may be implemented by a UE 115 and/or a base station 105 as described with reference
to FIGs. 1 and 2.
[0090] Resource mapping scheme 400 may include a preamble 405-a and one or more mapped resources
410-a for a payload of msgA. Preamble 405-a may represent a preamble of a msgA and
mapped resources 410 may represent resources for a payload of a msgA that are associated
with subsets of preamble 405-a. For instance, mapped resource 410-a may be associated
with a first subset of preamble 405-a (e.g., subset A), mapped resource 410-b may
be associated with a second subset of preamble 405-a. (e.g., subset B), and mapped
resources 410-c may be associated with a third subset of preamble 405-a (e.g., subset
C). Each mapped resource 410 may include a DMRS and a PUSCH. It should be noted that
the present example may also apply to msgB transmissions. For instance, instead of
a preamble 405-a, a PDCCH and/or a DCI of the PDCCH may be transmitted. Additionally,
instead of a PUSCH being transmitted on mapped resources 410, a PDSCH may be transmitted
on mapped resources 410. Resource mapping scheme 400 may be chosen based on a RRC
state of a UE 115 (resource mapping scheme 400 may be chosen if a UE 115 is in an
idle state and resource mapping scheme 401 may be used if the UE 115 is in a connected
state) associated with msgA (or msgB, if referring to PDCCH and/or PDSCH). Subsets
A, B, and C may be made mutually exclusive and/or partially overlapping.
[0091] Preamble 405-a may be disjoint in time from mapped resources 410 for a msgA payload
(e.g., before mapped resources 410-a, 410-b, and 410-c), but may overlap in frequency
with at least some of mapped resources 410 for msgA payload (e.g., preamble 405-a
may overlap with mapped resources 410-a, 410-b, and 410-c, but there may be other
mapped resources 410 that preamble 405-a does not overlap). Mapped resources 410 for
a msgA payload may overlap at least partially in time, but may be disjoint in frequency.
For instance mapped resource 410-a. may span a first frequency range, mapped resource
410-b may span a second frequency range disjoint from the first, and mapped resource
410-c may span a third frequency range disjoint from the first and second. It should
be noted that extension to space domain may also be used by considering beam sweeping
and/or beam forming. Different TBSs and/or MCSs associated with the same or different
RRC states may be mapped to different mapped resources 410. In some cases, a first
set of the mapped resources 410 (e.g., mapped resources 410-a and 410-b) may be used
if UE 115-a is associated with a first RRC state (e.g., an idle state), a first TBS,
and/or a first MCS, and a second set of the mapped resources 410 (e.g., mapped resource
410-c) may be used if UE 115-a is associated with a second RRC state (e.g., an inactive
state) a second TBS, and/or a second MCS. Each set may share common mapped resources
410 with other sets or may have mapped resources 410 distinct from other sets. Alternatively,
the same mapped resources 410 may be transmitted on for all RRC states.
[0092] A base station 105 and a UE 115 may use resource mapping scheme 400 in situations
where the base station 105 and the UE 115 are communicating in licensed spectrum.
Additionally or alternatively, a base station 105 and a UE 115 may use resource mapping
scheme 400 in situations where time and/or channel availability is constrained (e.g.,
preamble 405-a and mapped resources 410 are to be transmitted within a certain duration
of time).
[0093] FIG. 4B illustrates an example of a resource mapping scheme 401 that supports signaling support
and resource mapping for two-step random access in accordance with aspects of the
present disclosure. In some examples, resource mapping scheme 401 may implement aspects
of wireless communications system 100. For instance, resource mapping scheme 401 may
be implemented by a UE 115 and/or a base station 105 as described with reference to
FIGs. 1 and 2.
[0094] Resource mapping scheme 401 may include a preamble 405-b and one or more mapped resources
410 for a payload of msgA. Preamble 405-b may represent a preamble of a msgA and mapped
resources 410 may represent resources of a payload of msgA that are associated with
subsets of preamble 405-b. For instance, mapped resource 410-d may be associated with
a first subset of preamble 405-b (e.g., subset A), mapped resource 410-e may be associated
with a second subset of preamble 405-b (e.g., subset B), and mapped resources 410-f
may be associated with a third subset of preamble 405-b (e.g., subset C). Each mapped
resource 410 may include a DMRS and a PUSCH. It should be noted that the present example
may also apply to msgB transmissions. For instance, instead of a preamble 405-b, a
PDCCH and/or a DCI of the PDCCH may be transmitted. Additionally, instead of a PUSCH
being transmitted on mapped resources 410, a PDSCH may be transmitted on mapped resources
410. Resource mapping scheme 400 may be chosen based on a RRC state of a UE 115 (resource
mapping scheme 400 may be chosen if a UE 115 is in an idle state and resource mapping
scheme 401 may be used if the UE 115 is in a connected state) associated with msgA
(or msgB, if referring to PDCCH and/or PDSCH). Subsets A, B, and C may be made mutually
exclusive and/or partially overlapping.
[0095] Preamble 405-b may be disjoint in time from mapped resources 410 for a msgA payload
(e.g., before mapped resources 410-d, 410-e, and 410-f), but may overlap in frequency
with at least some of mapped resources 410 for a msgA payload (e.g., preamble 405-b
may overlap with mapped resources 410-d, 410-e, and 410-f, but there may be other
mapped resources 410 that preamble 405-b does not overlap). Mapped resources 410 may
overlap at least partially in frequency, but may be disjoint in time. For instance
mapped resource 410-d may span a first time duration, mapped resource 410-e may span
a second time duration disjoint from the first, and mapped resource 410-f may span
a third time duration disjoint from the first and second. It should be noted that
extension to space domain may also be used by considering beam sweeping and/or beam
forming. Different TBSs and/or MCSs associated with the same or different RRC states
may be mapped to different mapped resources 410. In some cases, a first set of the
mapped resources 410 (e.g., mapped resources 410-d and 410-e) may be used if a UE
115 is associated with a first RRC state (e.g., an idle state), a first TBS, and/or
a first MCS and a second set of the mapped resources 410 (e.g., mapped resource 410-f)
may be used if UE 115 is associated with a second RRC state (e.g., an inactive state),
a second TBS, and/or a second MCS. Each set may share common mapped resources 410
with other sets or may have mapped resources 410 distinct from other sets. Alternatively,
the same mapped resources 410 may be transmitted on for all RRC states.
[0096] A base station 105 and a UE 115 may use resource mapping scheme 401 in situations
where the base station 105 and the UE 115 are communicating in licensed spectrum.
Additionally or alternatively, a base station 105 and a UE 115 may use resource mapping
scheme 401 in situations where frequency range is constrained (e.g., preamble 405-b
and mapped resources 410 are to be within a certain range of frequencies).
[0097] FIG. 4C illustrates an example of a resource mapping scheme 402 that supports signaling support
and resource mapping for two-step random access in accordance with aspects of the
present disclosure. In some examples, resource mapping scheme 402 may implement aspects
of wireless communications system 100. For instance, resource mapping scheme 402 may
be implemented by a UE 115 and/or a base station 105 as described with reference to
FIGs. 1 and 2.
[0098] Resource mapping scheme 402 may include a preamble 405-c and one or more mapped resources
410 for a payload of msgA. Preamble 405-c may represent a preamble of a msgA and mapped
resources 410 may represent resources for a payload of msgA that are associated with
subsets of preamble 405-c. For instance, mapped resource 410-g may be associated with
a first subset of preamble 405-c (e.g., subset A), mapped resource 410-h may be associated
with a second subset of preamble 405-c (e.g., subset B), and mapped resources 410-i
may be associated with a third subset of preamble 405-c (e.g., subset C). Each mapped
resource 410 may include a DMRS and a PUSCH. It should be noted that the present example
may also apply to msgB transmissions. For instance, instead of a preamble 405-c, a
PDCCH and/or a DCI of the PDCCH may be transmitted. Additionally, instead of a PUSCH
being transmitted on mapped resources 410, a PDSCH may be transmitted on mapped resources
410. Resource mapping scheme 400 may be chosen based on a RRC state of a UE 115 (resource
mapping scheme 402 may be chosen if a UE 115 is in an idle state and resource mapping
scheme 401 may be used if the UE 115 is in a connected state) associated with msgA
(or msgB, if referring to PDCCH and/or PDSCH). Subsets A, B, and C may be made mutually
exclusive and/or partially overlapping.
[0099] Preamble 405-c may be disjoint in frequency from mapped resources 410 for a msgA
payload (e.g., spanning a frequency range above or below mapped resources 410-g, 410-h,
and 410-i), but may overlap in time with at least some of mapped resources 410 for
a msgA payload (e.g., preamble 405-a may overlap in time with mapped resources 410-g,
410-h, and 410-i, but there may be other mapped resources 410 that preamble 405-c
does not overlap in time with). Mapped resources 410 may overlap at least partially
in time, but may be disjoint in frequency. For instance mapped resource 410-g may
span a first frequency range, mapped resource 410-h may span a second frequency range
disjoint from the first, and mapped resource 410-i may span a third frequency range
disjoint from the first and second. It should be noted that extension to space domain
may also be used by considering beam sweeping and/or beam forming. Different TBSs
and/or MCSs associated with the same or different RRC states may be mapped to different
mapped resources 410. In some cases, a first set of the mapped resources 410 (e.g.,
mapped resources 410-g and 410-h) may be used if UE 115-a is associated with a first
RRC state (e.g., an idle state), first TBS, and/or first MCS and a second set of the
mapped resources 410 (e.g., mapped resource 410-1) may be used if UE 115-a is associated
with a second RRC state (e.g., an inactive state), a second TBS, and/or a second MCS.
Each set may share common mapped resources 410 with other sets or may have mapped
resources 410 distinct from other sets. Alternatively, the same mapped resources 410
may be transmitted on for all RRC states.
[0100] A base station 105 and a UE 115 may use resource mapping scheme 402 in situations
where the base station 105 and the UE 115 are communicating in unlicensed spectrum.
Additionally or alternatively, a base station 105 and a UE 115 may use resource mapping
scheme 402 in situations where time and/or channel availability is constrained (e.g.,
preamble 405-c and mapped resources 410 are to be transmitted within a certain duration
of time).
[0101] FIG. 5 illustrates an example of a process flow 500 that supports signaling support and
resource mapping for two-step random access in accordance with aspects of the present
disclosure. In some examples, process flow 500 may implement aspects of wireless communications
systems 100 and 200. For instance, process flow 5 00 may include UE 1.15-b and base
station 1 05-b, which may be examples of a UE 115 and a base station 105 as described
with reference to FIGs. 1 and 2.
[0102] At 505, base station 105-b may transmit an indication of a resource configuration
for a RA procedure (e.g., via a SIB, RRC signaling, or page signaling). The resource
configuration may identify multiple sets of transmission resources corresponding to
multiple RRC states (e.g., one set of transmission resources may be used if UE 115-b
is in an idle state, another if UE 115-b is in a connected state). UE 115-b may receive
the indication.
[0103] At 510, UE 115-b may identify an RRC state. For instance, UE 115-b may identify if
it is operating in a connected, idle, or inactive state (e.g., in RRC_CONNECTED, RRC_IDLE,
or RRC_INACTIVE).
[0104] At 515, UE 115-b may determine a set of transmission resources based on the indication
of the resource configuration and the identified RRC state. The set of resources may
be determined for a first message of the RA procedure. In one example, if UE 115-b
is in an idle state, UE 115-b may choose a set of transmission resources from the
indication corresponding to the idle state. In some cases, the set of transmission
resources may be determined based on identifying one or more transmission parameters
(e.g., TBS and/or MCS) to be used by UE 115-b or a UE ID (e.g., a MA signature and/or
a RA-RNTI) identified based on a RRC state of UE 115-b.
[0105] At 520, UE 115-b may determine a set of resources for reception of the second RA
procedure message (e.g., msgB).
[0106] At 525, UE 115-b may transmit a first message of the RA procedure using the determined
transmission resources. Base station 105-b may receive the first message over the
determined transmission resources.
[0107] At 530, base station 105-b may identify an RRC state of UE 115-b based on the received
first message and/or the transmitted indication of the resource configuration.
[0108] At 535, base station 105-b may transmit a second message of the RA procedure. The
second message may be sent in response to the received first message and may be received
by UE 115-b. In some cases, UE 115-b may monitor for the second message based on a
UE ID (e.g., a MA signature and/or a RA-RNT1) identified based on a RRC state of UE
115-b. Additionally or alternatively, UE 115-b may monitor for the second message
based on determining a search space for a control region and/or time duration (e.g.,
a RAR window) of the second message, where the search space and/or time duration may
be determined based on the identified RRC state of UE 115-b.
[0109] FIG. 6 shows a block diagram 600 of a device 605 that supports signaling support and resource
mapping for two-step random access in accordance with aspects of the present disclosure.
The device 605 may be an example of aspects of a UE 115 as described herein. The device
605 may include a receiver 610, a communications manager 615, and a transmitter 620.
The device 605 may also include a processor. Each of these components may be in communication
with one another (e.g., via one or more buses).
[0110] The receiver 610 may receive information such as packets, user data, or control information
associated with various information channels (e.g., control channels, data channels,
and information related to signaling support and resource mapping for two-step random
access, etc.). Information may be passed on to other components of the device 605.
The receiver 610 may be an example of aspects of the transceiver 920 described with
reference to FIG. 9. The receiver 610 may utilize a single antenna or a set of antennas.
[0111] The communications manager 615 may receive, from a base station, an indication of
a resource configuration for a random access procedure, the resource configuration
identifying a set of sets of transmission resources corresponding to a set of radio
resource control states, identify a radio resource control state of the UE, determine
a set of transmission resources based on the indication of the resource configuration,
a transport format, and the identified radio resource control state, and transmit
a first message of the random access procedure to the base station using the determined
transmission resources. The communications manager 615 may be an example of aspects
of the communications manager 910 described herein.
[0112] The communications manager 615, or its sub-components, may be implemented in hardware,
code (e.g., software or firmware) executed by a processor, or any combination thereof.
If implemented in code executed by a processor, the functions of the communications
manager 615, or its sub-components may be executed by a general-purpose processor,
a digital signal processor (DSP), an application-specific integrated circuit (ASIC),
a fieldprogrammable gate array (FPGA) or other programmable logic device, discrete
gate or transistor logic, discrete hardware components, or any combination thereof
designed to perform the functions described in the present disclosure.
[0113] The communications manager 615, or its sub-components, may be physically located
at various positions, including being distributed such that portions of functions
are implemented at different physical locations by one or more physical components.
In some examples, the communications manager 615, or its sub-components, may be a
separate and distinct component in accordance with various aspects of the present
disclosure. In some examples, the communications manager 615, or its sub-components,
may be combined with one or more other hardware components, including but not limited
to an input/output (I/O) component, a transceiver, a network server, another computing
device, one or more other components described in the present disclosure, or a combination
thereof in accordance with various aspects of the present disclosure.
[0114] The transmitter 620 may transmit signals generated by other components of the device
605. In some examples, the transmitter 620 may be collocated with a receiver 610 in
a transceiver module. For example, the transmitter 620 may be an example of aspects
of the transceiver 920 described with reference to FIG. 9. The transmitter 620 may
utilize a single antenna or a set of antennas.
[0115] FIG. 7 shows a block diagram 700 of a device 705 that supports signaling support and resource
mapping for two-step random access in accordance with aspects of the present disclosure.
The device 705 may be an example of aspects of a device 605, or a UE 115 as described
herein. The device 705 may include a receiver 710, a communications manager 715, and
a transmitter 740. The device 705 may also include a processor. Each of these components
may be in communication with one another (e.g., via one or more buses).
[0116] The receiver 710 may receive information such as packets, user data, or control information
associated with various information channels (e.g., control channels, data channels,
and information related to signaling support and resource mapping for two-step random
access, etc.). Information may be passed on to other components of the device 705.
The receiver 710 may be an example of aspects of the transceiver 920 described with
reference to FIG. 9. The receiver 710 may utilize a single antenna or a set of antennas.
[0117] The communications manager 715 may be an example of aspects of the communications
manager 615 as described herein. The communications manager 715 may include a resource
configuration receiver 720, an UE RRC state identifier 725, a transmission resource
determiner 730, and a first message transmitter 735. The communications manager 715
may be an example of aspects of the communications manager 910 described herein.
[0118] The resource configuration receiver 720 may receive, from a base station, an indication
of a resource configuration for a random access procedure, the resource configuration
identifying a set of sets of transmission resources corresponding to a set of radio
resource control states.
[0119] The UE RRC state identifier 725 may identify a radio resource control state of the
UE.
[0120] The transmission resource determiner 730 may determine a set of transmission resources
based on the indication of the resource configuration, a transport format, and the
identified radio resource control state.
[0121] The first message transmitter 735 may transmit a first message of the random access
procedure to the base station using the determined transmission resources.
[0122] The transmitter 740 may transmit signals generated by other components of the device
705. In some examples, the transmitter 740 may be collocated with a receiver 710 in
a transceiver module. For example, the transmitter 740 may be an example of aspects
of the transceiver 920 described with reference to FIG. 9. The transmitter 740 may
utilize a single antenna or a set of antennas.
[0123] FIG. 8 shows a block diagram 800 of a communications manager 805 that supports signaling
support and resource mapping for two-step random access in accordance with aspects
of the present disclosure. The communications manager 805 may be an example of aspects
of a communications manager 615, a communications manager 715, or a communications
manager 910 described herein. The communications manager 805 may include a resource
configuration receiver 810, an UE RRC state identifier 815, a transmission resource
determiner 820, a first message transmitter 825, and a second message monitoring component
830. Each of these modules may communicate, directly or indirectly, with one another
(e.g., via one or more buses).
[0124] The resource configuration receiver 810 may receive, from a base station, an indication
of a resource configuration for a random access procedure, the resource configuration
identifying a set of sets of transmission resources corresponding to a set of radio
resource control states. In some examples, the resource configuration receiver 810
may first time resources different from a common set of time resources shared by the
first uplink data portion and the second data uplink portion; or first frequency resources
different from a common set of frequency resources shared by the first uplink data
portion and the second data uplink portion; or first space resources different from
a common set of space resources shared by the first uplink data portion and the second
data uplink portion; or a combination thereof. In some examples, the resource configuration
receiver 810 may receive system information, or radio resource control signaling,
or a paging signal, or a combination thereof, including the indication of the resource
configuration. In some cases, the set of sets of transmission resources include at
least a first set of transmission resources and a second set of transmissions resources,
the first set of transmission resources include a first uplink data portion corresponding
to a first subset of a preamble portion, and the second set of transmission resources
include a second uplink data portion corresponding to a second subset of the preamble
portion. In some cases, the first uplink data portion of the first set of transmission
resources and the second uplink data portion of the second set of transmission resources
share a common set of frequency resources. In some cases, the first uplink data portion
of the first set of transmission resources and the second uplink data portion of the
second set of transmission resources share a common set of time resources. In some
cases, the first uplink data portion of the first set of transmission resources and
the second uplink data portion of the second set of transmission resources share a
common set of space resources. In some cases, the preamble portion shares a common
set of time resources, or a common set of frequency resources, or a common set of
space resources, or a combination thereof, with the first uplink data portion and
the second uplink data portion. In some cases, the set of sets of transmission resources
include time resources, or frequency resources, or spatial resources, or a combination
thereof.
[0125] The UE. RRC state identifier 815 may identify a radio resource control state of the
UE. In some examples, the UE RRC state identifier 815 may identify at least one transmission
parameter to be used by the UE to transmit the first message, where the set of transmission
resources is determined based on the indication of the resource configuration, the
identified radio resource control state, and the at least one transmission parameter.
In some examples, the UE RRC state identifier 815 may determine a UE identifier of
the UE based on the identified radio resource control state of the UE, where the set
of transmission resources is determined based on the indication of the resource configuration,
the identified radio resource control state, and the identifier of the UE. In some
examples, the UE RRC state identifier 815 may determine a UE identifier of the UE
based on the identified radio resource control state of the UE. In some examples,
the UE RRC state identifier 815 may identify that the UE is operating in one of a
radio resource control inactive state, or a radio resource control connected state,
or a radio resource control idle state.
[0126] The transmission resource determiner 820 may determine a set of transmission resources
based on the indication of the resource configuration, a transport format, and the
identified radio resource control state.
[0127] The first message transmitter 825 may transmit a first message of the random access
procedure to the base station using the determined transmission resources. In some
examples, the first message transmitter 825 may identify that the UE lacks a valid
timing advance value for the random access procedure, where the first message is transmitted
regardless of the UE lacking the valid timing advance value.
[0128] The second message monitoring component 830 may monitor, based on the determined
UE identifier, for a second message of the random access procedure transmitted by
the base station in response to the transmitted first message. In some examples, the
second message monitoring component 830 may determine a search space for a control
region of the second message based on the identified radio resource control state
of the UE, where the monitoring is further based on the determined search space. In
some examples, the second message monitoring component 830 may determine a time duration
for at least a portion of the second message based on the identified radio resource
control state of the UE, where the monitoring is further based on the determined time
duration. In some examples, the second message monitoring component 830 may receive,
in response to the transmitted first message, the second message of the two-step random
access procedure.
[0129] FIG. 9 shows a diagram of a system 900 including a device 905 that supports signaling support
and resource mapping for two-step random access in accordance with aspects of the
present disclosure. The device 905 may be an example of or include the components
of device 605, device 705, or a UE 115 as described herein. The device 905 may include
components for bi-directional voice and data communications including components for
transmitting and receiving communications, including a communications manager 910,
an I/O controller 915, a transceiver 920, an antenna 925, memory 930, and a processor
940. These components may be in electronic communication via one or more buses (e.g.,
bus 945).
[0130] The communications manager 910 may receive, from a base station, an indication of
a resource configuration for a random access procedure, the resource configuration
identifying a set of sets of transmission resources corresponding to a set of radio
resource control states, identify a radio resource control state of the UE, determine
a set of transmission resources based on the indication of the resource configuration
and the identified radio resource control state, and transmit a first message of the
random access procedure to the base station using the determined transmission resources.
[0131] The I/O controller 915 may manage input and output signals for the device 905. The
I/O controller 915 may also manage peripherals not integrated into the device 905.
In some cases, the I/O controller 915 may represent a physical connection or port
to an external peripheral. In some cases, the I/O controller 915 may utilize an operating
system such as iOS
®, ANDROID
®, MS-DOS
®, MS-WINDOWS
®, OS/2
®, UNIX
®, LINUX
®, or another known operating system. In other cases, the I/O controller 915 may represent
or interact with a modem, a keyboard, a mouse, a touchscreen, or a similar device.
In some cases, the I/O controller 915 may be implemented as part of a processor. In
some cases, a user may interact with the device 905 via the I/O controller 915 or
via hardware components controlled by the I/O controller 915.
[0132] The transceiver 920 may communicate bi-directionally, via one or more antennas, wired,
or wireless links as described above. For example, the transceiver 920 may represent
a wireless transceiver and may communicate bi-directionally with another wireless
transceiver. The transceiver 920 may also include a modem to modulate the packets
and provide the modulated packets to the antennas for transmission, and to demodulate
packets received from the antennas.
[0133] In some cases, the wireless device may include a single antenna 925. However, in
some cases the device may have more than one antenna 925, which may be capable of
concurrently transmitting or receiving multiple wireless transmissions.
[0134] The memory 930 may include RAM and ROM. The memory 930 may store computer-readable,
computer-executable code 935 including instructions that, when executed, cause the
processor to perform various functions described herein. In some cases, the memory
930 may contain, among other things, a basic input/output system (BIOS) which may
control basic hardware or software operation such as the interaction with peripheral
components or devices.
[0135] The processor 940 may include an intelligent hardware device, (e.g., a general-purpose
processor, a DSP, a CPU, a microcontroller, an ASIC, an FPGA, a programmable logic
device, a discrete gate or transistor logic component, a discrete hardware component,
or any combination thereof). In some cases, the processor 940 may be configured to
operate a memory array using a memory controller. In other cases, a memory controller
may be integrated into the processor 940. The processor 940 may be configured to execute
computer-readable instructions stored in a memory (e.g., the memory 930) to cause
the device 905 to perform various functions (e.g., functions or tasks supporting signaling
support and resource mapping for two-step random access).
[0136] The code 935 may include instructions to implement aspects of the present disclosure,
including instructions to support wireless communications. The code 935 may be stored
in a non-transitory computer-readable medium such as system memory or other type of
memory. In some cases, the code 935 may not be directly executable by the processor
940 but may cause a computer (e.g., when compiled and executed) to perform functions
described herein.
[0137] FIG. 10 shows a block diagram 1000 of a device 1005 that supports signaling support and resource
mapping for two-step random access in accordance with aspects of the present disclosure.
The device 1005 may be an example of aspects of a base station 105 as described herein.
The device 1005 may include a receiver 1010, a communications manager 1015, and a
transmitter 1020. The device 1005 may also include a processor. Each of these components
may be in communication with one another (e.g., via one or more buses).
[0138] The receiver 1010 may receive information such as packets, user data, or control
information associated with various information channels (e.g., control channels,
data channels, and information related to signaling support and resource mapping for
two-step random access, etc.). Information may be passed on to other components of
the device 1005. The receiver 1010 may be an example of aspects of the transceiver
1320 described with reference to FIG. 13. The receiver 1010 may utilize a single antenna
or a set of antennas.
[0139] The communications manager 1015 may transmit, to a UE, an indication of a resource
configuration for a random access procedure, the resource configuration identifying
a set of sets of transmission resources corresponding to a set of radio resource control
states, receive, from the UE, a first message of the random access procedure, identify
a radio resource control state of the UE based on the received first message of the
random access procedure and the transmitted indication of the resource configuration,
and transmit, to the UE based on the identified radio resource control state of the
UE, a second message of the random access procedure in response to the received first
message. The communications manager 1015 may be an example of aspects of the communications
manager 1310 described herein.
[0140] The communications manager 1015, or its sub-components, may be implemented in hardware,
code (e.g., software or firmware) executed by a processor, or any combination thereof.
If implemented in code executed by a processor, the functions of the communications
manager 1015, or its sub-components may be executed by a general-purpose processor,
a DSP, an application-specific integrated circuit (ASIC), a FPGA or other programmable
logic device, discrete gate or transistor logic, discrete hardware components, or
any combination thereof designed to perform the functions described in the present
disclosure.
[0141] The communications manager 1015, or its sub-components, may be physically located
at various positions, including being distributed such that portions of functions
are implemented at different physical locations by one or more physical components.
In some examples, the communications manager 1015, or its sub-components, may be a
separate and distinct component in accordance with various aspects of the present
disclosure. In some examples, the communications manager 1015, or its sub-components,
may be combined with one or more other hardware components, including but not limited
to an input/output (I/O) component, a transceiver, a network server, another computing
device, one or more other components described in the present disclosure, or a combination
thereof in accordance with various aspects of the present disclosure.
[0142] The transmitter 1020 may transmit signals generated by other components of the device
1005. In some examples, the transmitter 1020 may be collocated with a receiver 1010
in a transceiver module. For example, the transmitter 1020 may be an example of aspects
of the transceiver 1320 described with reference to FIG. 13. The transmitter 1020
may utilize a single antenna or a set of antennas.
[0143] FIG. 11 shows a block diagram 1 100 of a device 1105 that supports signaling support and
resource mapping for two-step random access in accordance with aspects of the present
disclosure. The device 1105 may be an example of aspects of a device 1005, or a base
station 105 as described herein. The device 1105 may include a receiver 1110, a communications
manager 1115, and a transmitter 1140. The device 1105 may also include a processor.
Each of these components may be in communication with one another (e.g., via one or
more buses).
[0144] The receiver 1110 may receive information such as packets, user data, or control
information associated with various information channels (e.g., control channels,
data channels, and information related to signaling support and resource mapping for
two-step random access, etc.). Information may be passed on to other components of
the device 1105. The receiver 1110 may be an example of aspects of the transceiver
1320 described with reference to FIG. 13. The receiver 1110 may utilize a single antenna
or a set of antennas.
[0145] The communications manager 1115 may be an example of aspects of the communications
manager 1015 as described herein. The communications manager 1115 may include a resource
configuration transmitter 1120, a first message receiver 1125, a base station RRC
state identifier 1130, and a second message transmitter 1135. The communications manager
1115 may be an example of aspects of the communications manager 1310 described herein.
[0146] The resource configuration transmitter 1120 may transmit, to a UE, an indication
of a resource configuration for a random access procedure, the resource configuration
identifying a set of sets of transmission resources corresponding to a set of radio
resource control states.
[0147] The first message receiver 1125 may receive, from the UE, a first message of the
random access procedure.
[0148] The base station RRC state identifier 1130 may identify a radio resource control
state of the UE based on the received first message of the random access procedure
and the transmitted indication of the resource configuration.
[0149] The second message transmitter 1135 may transmit, to the UE based on the identified
radio resource control state of the UE, a second message of the random access procedure
in response to the received first message.
[0150] The transmitter 1140 may transmit signals generated by other components of the device
1105. In some examples, the transmitter 1140 may be collocated with a receiver 1110
in a transceiver module. For example, the transmitter 1140 may be an example of aspects
of the transceiver 1320 described with reference to FIG. 13. The transmitter 1140
may utilize a single antenna or a set of antennas.
[0151] FIG. 12 shows a block diagram 1200 of a communications manager 1205 that supports signaling
support and resource mapping for two-step random access in accordance with aspects
of the present disclosure. The communications manager 1205 may be an example of aspects
of a communications manager 1015, a communications manager 1115, or a communications
manager 1310 described herein. The communications manager 1205 may include a resource
configuration transmitter 1210, a first message receiver 1215, a base station RRC
state identifier 1220, a second message transmitter 1225, and a transmission resource
identifier 1230. Each of these modules may communicate, directly or indirectly, with
one another (e.g., via one or more buses).
[0152] The resource configuration transmitter 1210 may transmit, to a UE, an indication
of a resource configuration for a random access procedure, the resource configuration
identifying a set of sets of transmission resources corresponding to a set of radio
resource control states. In some examples, the resource configuration transmitter
1210 may transmit system information, or radio resource control signaling, or a paging
signal, or a combination thereof, including the indication of the resource configuration.
In some cases, the set of sets of transmission resources include time resources, or
frequency resources, or spatial resources, or a combination thereof. In some cases,
the random access procedure is a two-step random access procedure that includes the
first message and the second message.
[0153] The first message receiver 1215 may receive, from the UE, a first message of the
random access procedure.
[0154] The base station RRC state identifier 1220 may identify a radio resource control
state of the UE based on the received first message of the random access procedure
and the transmitted indication of the resource configuration. In some examples, the
base station RRC state identifier 1220 may identify at least one transmission parameter
used by the UE to transmit the first message, where the radio resource control state
is identified based on the identified at least one transmission parameter. In some
examples, the base station RRC state identifier 1220 may determine a UE identifier
based on the first message. In some examples, the base station RRC state identifier
1220 may identify that the UE is operating in one of a radio resource control inactive
state, or a radio resource control connected state, or an radio resource control idle
state.
[0155] The second message transmitter 1225 may transmit, to the UE based on the identified
radio resource control state of the UE, a second message of the random access procedure
in response to the received first message.
[0156] The transmission resource identifier 1230 may identify a first set of transmission
resources of the set of sets of transmission resources for the second message based
on the UE identifier and the identified radio resource control state.
[0157] FIG. 13 shows a diagram of a system 1300 including a device 1305 that supports signaling
support and resource mapping for two-step random access in accordance with aspects
of the present disclosure. The device 1305 may be an example of or include the components
of device 1005, device 1105, or a base station 105 as described herein. The device
1305 may include components for bi-directional voice and data communications including
components for transmitting and receiving communications, including a communications
manager 1310, a network communications manager 1315, a transceiver 1320, an antenna
1325, memory 1330, a processor 1340, and an inter-station communications manager 1345.
These components may be in electronic communication via one or more buses (e.g., bus
1350).
[0158] The communications manager 1310 may transmit, to a UE, an indication of a resource
configuration for a random access procedure, the resource configuration identifying
a set of sets of transmission resources corresponding to a set of radio resource control
states, receive, from the UE, a first message of the random access procedure, identify
a radio resource control state of the UE based on the received first message of the
random access procedure and the transmitted indication of the resource configuration,
and transmit, to the UE based on the identified radio resource control state of the
UE, a second message of the random access procedure in response to the received first
message.
[0159] The network communications manager 13 15 may manage communications with the core
network (e.g., via one or more wired backhaul links). For example, the network communications
manager 1315 may manage the transfer of data communications for client devices, such
as one or more UEs 115.
[0160] The transceiver 1320 may communicate bi-directionally, via one or more antennas,
wired, or wireless links as described above. For example, the transceiver 1320 may
represent a wireless transceiver and may communicate bi-directionally with another
wireless transceiver. The transceiver 1320 may also include a modem to modulate the
packets and provide the modulated packets to the antennas for transmission, and to
demodulate packets received from the antennas.
[0161] In some cases, the wireless device may include a single antenna 1325. However, in
some cases the device may have more than one antenna 1325, which may be capable of
concurrently transmitting or receiving multiple wireless transmissions.
[0162] The memory 1330 may include RAM, ROM, or a combination thereof. The memory 1330 may
store computer-readable code 1335 including instructions that, when executed by a
processor (e.g., the processor 1340) cause the device to perform various functions
described herein. In some cases, the memory 1330 may contain, among other things,
a BIOS which may control basic hardware or software operation such as the interaction
with peripheral components or devices.
[0163] The processor 1340 may include an intelligent hardware device, (e.g., a general-purpose
processor, a DSP, a CPU, a microcontroller, an ASIC, an FPGA, a programmable logic
device, a discrete gate or transistor logic component, a discrete hardware component,
or any combination thereof). In some cases, the processor 1340 may be configured to
operate a memory array using a memory controller. In some cases, a memory controller
may be integrated into processor 1340. The processor 1340 may be configured to execute
computer-readable instructions stored in a memory (e.g., the memory 1330) to cause
the device 1305 to perform various functions (e.g., functions or tasks supporting
signaling support and resource mapping for two-step random access).
[0164] The inter-station communications manager 1345 may manage communications with other
base station 105, and may include a controller or scheduler for controlling communications
with UEs 115 in cooperation with other base stations 105. For example, the inter-station
communications manager 1345 may coordinate scheduling for transmissions to UEs 115
for various interference mitigation techniques such as beamforming or joint transmission.
In some examples, the inter-station communications manager 1345 may provide an X2
interface within an LTE/LTE-A wireless communication network technology to provide
communication between base stations 105.
[0165] The code 1335 may include instructions to implement aspects of the present disclosure,
including instructions to support wireless communications. The code 1335 may be stored
in a non-transitory computer-readable medium such as system memory or other type of
memory. In some cases, the code 1335 may not be directly executable by the processor
1340 but may cause a computer (e.g., when compiled and executed) to perform functions
described herein.
[0166] FIG. 14 shows a flowchart illustrating a method 1400 that supports signaling support and
resource mapping for two-step random access in accordance with aspects of the present
disclosure. The operations of method 1400 may be implemented by a UE 115 or its components
as described herein. For example, the operations of method 1400 may be performed by
a communications manager as described with reference to FIGs. 6 through 9. In some
examples, a UE may execute a set of instructions to control the functional elements
of the UE to perform the functions described below. Additionally or alternatively,
a UE may perform aspects of the functions described below using special-purpose hardware.
[0167] At 1405, the UE may receive, from a base station, an indication of a resource configuration
for a random access procedure, the resource configuration identifying a set of sets
of transmission resources corresponding to a set of radio resource control states.
The operations of 1405 may be performed according to the methods described herein.
In some examples, aspects of the operations of 1405 may be performed by a resource
configuration receiver as described with reference to FIGs. 6 through 9.
[0168] At 1410, the UE may identify a radio resource control state of the UE. The operations
of 1410 may be performed according to the methods described herein. In some examples,
aspects of the operations of 1410 may be performed by an UE. RRC state identifier
as described with reference to FIGs. 6 through 9.
[0169] At 1415, the UE may determine a set of transmission resources based on the indication
of the resource configuration, a transport format, and the identified radio resource
control state. The operations of 1415 may be performed according to the methods described
herein. In some examples, aspects of the operations of 1415 may be performed by a
transmission resource determiner as described with reference to FIGs. 6 through 9.
[0170] At 1420, the UE may transmit a first message of the random access procedure to the
base station using the determined transmission resource and the transport format.
The operations of 1420 may be performed according to the methods described herein.
In some examples, aspects of the operations of 1420 may be performed by a first message
transmitter as described with reference to FIGs. 6 through 9.
[0171] FIG. 15 shows a flowchart illustrating a method 1500 that supports signaling support and
resource mapping for two-step random access in accordance with aspects of the present
disclosure. The operations of method 1500 may be implemented by a UE 115 or its components
as described herein. For example, the operations of method 1500 may be performed by
a communications manager as described with reference to FIGs. 6 through 9. In some
examples, a UE may execute a set of instructions to control the functional elements
of the UE to perform the functions described below. Additionally or alternatively,
a UE may perform aspects of the functions described below using special-purpose hardware.
[0172] At 1505, the UE may receive, from a base station, an indication of a resource configuration
for a random access procedure, the resource configuration identifying a set of sets
of transmission resources corresponding to a set of radio resource control states.
The operations of 1505 may be performed according to the methods described herein.
In some examples, aspects of the operations of 1505 may be performed by a resource
configuration receiver as described with reference to FIGs. 6 through 9.
[0173] At 1510, the UE may identify a radio resource control state of the UE. The operations
of 1510 may be performed according to the methods described herein. In some examples,
aspects of the operations of 1510 may be performed by an UE RRC state identifier as
described with reference to FIGs. 6 through 9.
[0174] At 1515, the UE may identify at least one transmission parameter to be used by the
UE to transmit the first message. The operations of 1515 may be performed according
to the methods described herein. In some examples, aspects of the operations of 1515
may be performed by an UE RRC state identifier as described with reference to FIGs.
6 through 9.
[0175] At 1520, the UE may determine a set of transmission resources based on the indication
of the resource configuration, a transport format, the at least one transmission parameter,
and the identified radio resource control state. The operations of 1520 may be performed
according to the methods described herein. In some examples, aspects of the operations
of 1520 may be performed by a transmission resource determiner as described with reference
to FIGs. 6 through 9.
[0176] At 1525, the UE may transmit a first message of the random access procedure to the
base station using the determined transmission resources and the transport format.
The operations of 1525 may be performed according to the methods described herein.
In some examples, aspects of the operations of 1525 may be performed by a first message
transmitter as described with reference to FIGs. 6 through 9.
[0177] FIG. 16 shows a flowchart illustrating a method 1600 that supports signaling support and
resource mapping for two-step random access in accordance with aspects of the present
disclosure. The operations of method 1 600 may be implemented by a UE 115 or its components
as described herein. For example, the operations of method 1600 may be performed by
a communications manager as described with reference to FIGs. 6 through 9. In some
examples, a UE may execute a set of instructions to control the functional elements
of the UE to perform the functions described below. Additionally or alternatively,
a UE may perform aspects of the functions described below using special-purpose hardware.
[0178] At 1605, the UE may receive, from a base station, an indication of a resource configuration
for a random access procedure, the resource configuration identifying a set of sets
of transmission resources corresponding to a set of radio resource control states.
The operations of 1605 may be performed according to the methods described herein.
In some examples, aspects of the operations of 1605 may be performed by a resource
configuration receiver as described with reference to FIGs. 6 through 9.
[0179] At 1610, the UE may identify a radio resource control state of the UE. The operations
of 1610 may be performed according to the methods described herein. In some examples,
aspects of the operations of 1610 may be performed by an UE RRC state identifier as
described with reference to FIGs. 6 through 9.
[0180] At 1615, the UE may determine a UE identifier of the UE based on the identified radio
resource control state of the UE. The operations of 1615 may be performed according
to the methods described herein. In some examples, aspects of the operations of 1615
may be performed by an UE RRC state identifier as described with reference to FIGs.
6 through 9.
[0181] At 1620, the UE may determine a set of transmission resources based on the indication
of the resource configuration, a transport format, the UE identifier, and the identified
radio resource control state. The operations of 1620 may be performed according to
the methods described herein. In some examples, aspects of the operations of 1620
may be performed by a transmission resource determiner as described with reference
to FIGs. 6 through 9.
[0182] At 1625, the UE may transmit a first message of the random access procedure to the
base station using the determined transmission resources and the transport format.
The operations of 1625 may be performed according to the methods described herein.
In some examples, aspects of the operations of 1625 may be performed by a first message
transmitter as described with reference to FIGs. 6 through 9.
[0183] FIG. 17 shows a flowchart illustrating a method 1700 that supports signaling support
and resource mapping for two-step random access in accordance with aspects of the
present disclosure. The operations of method 1700 may be implemented by a UE 115 or
its components as described herein. For example, the operations of method 1700 may
be performed by a communications manager as described with reference to FIGs. 6 through
9. In some examples, a UE may execute a set of instructions to control the functional
elements of the UE to perform the functions described below. Additionally or alternatively,
a UE may perform aspects of the functions described below using special-purpose hardware.
[0184] At 1705, the UE may receive, from a base station, an indication of a resource configuration
for a random access procedure, the resource configuration identifying a set of sets
of transmission resources corresponding to a set of radio resource control states.
The operations of 1705 may be performed according to the methods described herein.
In some examples, aspects of the operations of 1705 may be performed by a resource
configuration receiver as described with reference to FIGs. 6 through 9.
[0185] At 1710, the UE may identify a radio resource control state of the UE. The operations
of 1710 may be performed according to the methods described herein. In some examples,
aspects of the operations of 1710 may be performed by an UE RRC state identifier as
described with reference to FIGs. 6 through 9.
[0186] At 1715, the UE may determine a UE identifier of the UE based on the identified radio
resource control state of the UE. The operations of 1715 may be performed according
to the methods described herein. In some examples, aspects of the operations of 1715
may be performed by an UE RRC state identifier as described with reference to FIGs.
6 through 9.
[0187] At 1720, the UE may determine a set of transmission resources based on the indication
of the resource configuration, a transport format, and the identified radio resource
control state. The operations of 1720 may be performed according to the methods described
herein. In some examples, aspects of the operations of 1720 may be performed by a
transmission resource determiner as described with reference to FIGs. 6 through 9.
[0188] At 1725, the UE may transmit a first message of the random access procedure to the
base station using the determined transmission resources and the transport format.
The operations of 1725 may be performed according to the methods described herein.
In some examples, aspects of the operations of 1725 may be performed by a first message
transmitter as described with reference to FIGs. 6 through 9.
[0189] At 1730, the UE may monitor, based on the determined UE identifier, for a second
message of the random access procedure transmitted by the base station in response
to the transmitted first message. The operations of 1730 may be performed according
to the methods described herein. In some examples, aspects of the operations of 1730
may be performed by a second message monitoring component as described with reference
to FIGs. 6 through 9.
[0190] FIG. 18 shows a flowchart illustrating a method 1800 that supports signaling support and
resource mapping for two-step random access in accordance with aspects of the present
disclosure. The operations of method 1800 may be implemented by a base station 105
or its components as described herein. For example, the operations of method 1800
may be performed by a communications manager as described with reference to FIGs.
10 through 13. In some examples, a base station may execute a set of instructions
to control the functional elements of the base station to perform the functions described
below. Additionally or alternatively, a base station may perform aspects of the functions
described below using special-purpose hardware.
[0191] At 1805, the base station may transmit, to a UE, an indication of a resource configuration
for a random access procedure, the resource configuration identifying a set of sets
of transmission resources corresponding to a set of radio resource control states.
The operations of 1805 may be performed according to the methods described herein.
In some examples, aspects of the operations of 1805 may be performed by a resource
configuration transmitter as described with reference to FIGs. 10 through 13.
[0192] At 1810, the base station may receive, from the UE, a first message of the random
access procedure. The operations of 1810 may be performed according to the methods
described herein. In some examples, aspects of the operations of 1810 may be performed
by a first message receiver as described with reference to FIGs. 10 through 13.
[0193] At 1815, the base station may identify a radio resource control state of the UE based
on the received first message of the random access procedure and the transmitted indication
of the resource configuration. The operations of 1815 may be performed according to
the methods described herein. In some examples, aspects of the operations of 1815
may be performed by a base station RRC state identifier as described with reference
to FIGs. 10 through 13.
[0194] At 1820, the base station may transmit, to the UE based on the identified radio resource
control state of the UE, a second message of the random access procedure in response
to the received first message. The operations of 1820 may be performed according to
the methods described herein. In some examples, aspects of the operations of 1820
may be performed by a second message transmitter as described with reference to FIGs.
10 through 13.
[0195] It should be noted that the methods described herein describe possible implementations,
and that the operations and the steps may be rearranged or otherwise modified and
that other implementations are possible. Further, aspects from two or more of the
methods may be combined.
[0196] Techniques described herein may be used for various wireless communications systems
such as code division multiple access (CDMA), time division multiple access (TDMA),
frequency division multiple access (FDMA), orthogonal frequency division multiple
access (OFDMA), single carrier frequency division multiple access (SC-FDMA), and other
systems. A CDMA system may implement a radio technology such as CDMA2000, Universal
Terrestrial Radio Access (UTRA), etc. CDMA2000 covers IS-2000, IS-95, and IS-856 standards.
IS-2000 Releases may be commonly referred to as CDMA2000 1X, 1X, etc. IS-856 (TIA-856)
is commonly referred to as CDMA2000 1xEV-DO, High Rate Packet Data (HRPD), etc. UTRA
includes Wideband CDMA (WCDMA) and other variants of CDMA. A TDMA system may implement
a radio technology such as Global System for Mobile Communications (GSM).
[0197] An OFDMA system may implement a radio technology such as Ultra Mobile Broadband (UMB),
Evolved UTRA (E-UTRA), Institute of Electrical and Electronics Engineers (IEEE) 802.11
(Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802.20, Flash-OFDM, etc. UTRA and E-UTRA are part
of Universal Mobile Telecommunications System (UMTS). LTE, LTE-A, and LTE-A Pro are
releases of UMTS that use E-UTRA. UTRA, E-UTRA, UMTS, LTE, LTE-A, LTE-A Pro, NR, and
GSM are described in documents from the organization named "3rd Generation Partnership
Project" (3GPP). CDMA2000 and UMB are described in documents from an organization
named "3rd Generation Partnership Project 2" (3GPP2). The techniques described herein
may be used for the systems and radio technologies mentioned herein as well as other
systems and radio technologies. While aspects of an LTE, LTE-A, LTE-A Pro, or NR system
may be described for purposes of example, and LTE, LTE-A, LTE-A Pro, or NR terminology
may be used in much of the description, the techniques described herein are applicable
beyond LTE, LTE-A, LTE-A Pro, or NR applications.
[0198] A macro cell generally covers a relatively large geographic area (e.g., several kilometers
in radius) and may allow unrestricted access by UEs with service subscriptions with
the network provider. A small cell may be associated with a lower-powered base station,
as compared with a macro cell, and a small cell may operate in the same or different
(e.g., licensed, unlicensed, etc.) frequency bands as macro cells. Small cells may
include pico cells, femto cells, and micro cells according to various examples. A
pico cell, for example, may cover a small geographic area and may allow unrestricted
access by UEs with service subscriptions with the network provider. A femto cell may
also cover a small geographic area (e.g., a home) and may provide restricted access
by UEs having an association with the femto cell (e.g., UEs in a closed subscriber
group (CSG), UEs for users in the home, and the like). An eNB for a macro cell may
be referred to as a macro eNB. An eNB for a small cell may be referred to as a small
cell eNB, a pico eNB, a femto eNB, or a home eNB. An eNB may support one or multiple
(e.g., two, three, four, and the like) cells, and may also support communications
using one or multiple component carriers.
[0199] The wireless communications systems described herein may support synchronous or asynchronous
operation. For synchronous operation, the base stations may have similar frame timing,
and transmissions from different base stations may be approximately aligned in time.
For asynchronous operation, the base stations may have different frame timing, and
transmissions from different base stations may not be aligned in time. The techniques
described herein may be used for either synchronous or asynchronous operations.
[0200] Information and signals described herein may be represented using any of a variety
of different technologies and techniques. For example, data, instructions, commands,
information, signals, bits, symbols, and chips that may be referenced throughout the
description may be represented by voltages, currents, electromagnetic waves, magnetic
fields or particles, optical fields or particles, or any combination thereof.
[0201] The various illustrative blocks and modules described in connection with the disclosure
herein may be implemented or performed with a general-purpose processor, a DSP, an
ASIC, an FPGA, or other programmable logic device, discrete gate or transistor logic,
discrete hardware components, or any combination thereof designed to perform the functions
described herein. A general-purpose processor may be a microprocessor, but in the
alternative, the processor may be any conventional processor, controller, microcontroller,
or state machine. A processor may also be implemented as a combination of computing
devices (e.g., a combination of a DSP and a microprocessor, multiple microprocessors,
one or more microprocessors in conjunction with a DSP core, or any other such configuration).
[0202] The functions described herein may be implemented in hardware, software executed
by a processor, firmware, or any combination thereof. If implemented in software executed
by a processor, the functions may be stored on or transmitted over as one or more
instructions or code on a computer-readable medium. Other examples and implementations
are within the scope of the disclosure and appended claims. For example, due to the
nature of software, functions described herein can be implemented using software executed
by a processor, hardware, firmware, hardwiring, or combinations of any of these. Features
implementing functions may also be physically located at various positions, including
being distributed such that portions of functions are implemented at different physical
locations.
[0203] Computer-readable media includes both non-transitory computer storage media and communication
media including any medium that facilitates transfer of a computer program from one
place to another. A non-transitory storage medium may be any available medium that
can be accessed by a general purpose or special purpose computer. By way of example,
and not limitation, non-transitory computer-readable media may include random-access
memory (RAM), read-only memory (ROM), electrically erasable programmable ROM (EEPROM),
flash memory, compact disk (CD) ROM or other optical disk storage, magnetic disk storage
or other magnetic storage devices, or any other non-transitory medium that can be
used to carry or store desired program code means in the form of instructions or data
structures and that can be accessed by a general-purpose or special-purpose computer,
or a general-purpose or special-purpose processor. Also, any connection is properly
termed a computer-readable medium. For example, if the software is transmitted from
a website, server, or other remote source using a coaxial cable, fiber optic cable,
twisted pair, digital subscriber line (DSL), or wireless technologies such as infrared,
radio, and microwave, then the coaxial cable, fiber optic cable, twisted pair, DSL,
or wireless technologies such as infrared, radio, and microwave are included in the
definition of medium. Disk and disc, as used herein, include CD, laser disc, optical
disc, digital versatile disc (DVD), floppy disk and Blu-ray disc where disks usually
reproduce data magnetically, while discs reproduce data optically with lasers. Combinations
of the above are also included within the scope of computer-readable media.
[0204] As used herein, including in the claims, "or" as used in a list of items (e.g., a
list of items prefaced by a phrase such as "at least one of" or "one or more of")
indicates an inclusive list such that, for example, a list of at least one of A, B,
or C means A or B or C or AB or AC or Σ3C or ABC (i.e., A and B and C). Also, as used
herein, the phrase "based on" shall not be construed as a reference to a closed set
of conditions. For example, an exemplary step that is described as "based on condition
A" may be based on both a condition A and a condition B without departing from the
scope of the present disclosure. In other words, as used herein, the phrase "based
on" shall be construed in the same manner as the phrase "based at least in part on."
[0205] In the appended figures, similar components or features may have the same reference
label. Further, various components of the same type may be distinguished by following
die reference label by a dash and a second label that distinguishes among the similar
components. If just the first reference label is used in the specification, the description
is applicable to any one of the similar components having the same first reference
label irrespective of the second reference label, or other subsequent reference label.
[0206] The description set forth herein, in connection with the appended drawings, describes
example configurations and does not represent all the examples that may be implemented
or that are within the scope of the claims. The term "exemplary" used herein means
"serving as an example, instance, or illustration," and not "preferred" or "advantageous
over other examples." The detailed description includes specific details for the purpose
of providing an understanding of the described techniques. These techniques, however,
may be practiced without these specific details. In some instances, well-known structures
and devices are shown in block diagram form in order to avoid obscuring the concepts
of the described examples.