BACKGROUND
Field
[0001] Aspects of the present disclosure relate generally to wireless communication systems,
and more particularly, to new radio (NR) power headroom report (PHR) design for millimeter
wave (mmWave) deployment.
Background
[0002] Wireless communication networks are widely deployed to provide various communication
services such as voice, video, packet data, messaging, broadcast, and the like. These
wireless networks may be multiple-access networks capable of supporting multiple users
by sharing the available network resources. Such networks, which are usually multiple
access networks, support communications for multiple users by sharing the available
network resources. One example of such a network is the Universal Terrestrial Radio
Access Network (UTRAN). The UTRAN is the radio access network (RAN) defined as a part
of the Universal Mobile Telecommunications System (UMTS), a third generation (3G)
mobile phone technology supported by the 3rd Generation Partnership Project (3GPP).
Examples of multiple-access network formats include Code Division Multiple Access
(CDMA) networks, Time Division Multiple Access (TDMA) networks, Frequency Division
Multiple Access (FDMA) networks, Orthogonal FDMA (OFDMA) networks, and Single-Carrier
FDMA (SC-FDMA) networks.
[0003] A wireless communication network may include a number of base stations or node Bs
that can support communication for a number of user equipments (UEs). A UE may communicate
with a base station via downlink and uplink. The downlink (or forward link) refers
to the communication link from the base station to the UE, and the uplink (or reverse
link) refers to the communication link from the UE to the base station.
[0004] A base station may transmit data and control information on the downlink to a UE
and/or may receive data and control information on the uplink from the UE. On the
downlink, a transmission from the base station may encounter interference due to transmissions
from neighbor base stations or from other wireless radio frequency (RF) transmitters.
On the uplink, a transmission from the UE may encounter interference from uplink transmissions
of other UEs communicating with the neighbor base stations or from other wireless
RF transmitters. This interference may degrade performance on both the downlink and
uplink.
[0005] As the demand for mobile broadband access continues to increase, the possibilities
of interference and congested networks grows with more UEs accessing the long-range
wireless communication networks and more short-range wireless systems being deployed
in communities. Research and development continue to advance wireless technologies
not only to meet the growing demand for mobile broadband access, but to advance and
enhance the user experience with mobile communications.
WO2014/109707A1 and
US2014/221038 describe methods of wireless communication according to the preamble of the present
independent claims.
3GPP document R1-1704542 by CATT discusses NR measurements and mobility management in IDLE and CONNECTED state.
SUMMARY
[0006] The invention is set out in the appended set of claims.
[0007] The foregoing has outlined rather broadly the features and technical advantages of
examples according to the disclosure in order that the detailed description that follows
may be better understood. Additional features and advantages will be described hereinafter.
The conception and specific examples disclosed may be readily utilized as a basis
for modifying or designing other structures for carrying out the same purposes of
the present disclosure. Such equivalent constructions do not depart from the scope
of the appended claims. Characteristics of the concepts disclosed herein, both their
organization and method of operation, together with associated advantages will be
better understood from the following description when considered in connection with
the accompanying figures. Each of the figures is provided for the purpose of illustration
and description, and not as a definition of the limits of the claims.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] A further understanding of the nature and advantages of the present disclosure may
be realized by reference to the following drawings. 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 the 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.
FIG. 1 is a block diagram illustrating details of a wireless communication system.
FIG. 2 is a block diagram illustrating a design of a base station and a UE.
FIG. 3 is a block diagram illustrating a wireless communication system including base
stations that use directional wireless beams.
FIG. 4 is a block diagram illustrating example blocks
FIG. 5 is a block diagram illustrating a base station communicating with a UE using
mmWave beamforming.
FIGs. 6A-6C are block diagrams illustrating a base station and UE
FIG. 7 is a block diagram illustrating example blocks
FIG. 8 is a block diagram illustrating example blocks executed to implement one aspect
of the present disclosure.
FIG. 9 is a block diagram illustrating an UE
DETAILED DESCRIPTION
[0009] The detailed description set forth below, in connection with the appended drawings
and appendix, is intended as a description of various configurations and is not intended
to limit the scope of the disclosure. Rather, the detailed description includes specific
details for the purpose of providing a thorough understanding of the inventive subject
matter. It will be apparent to those skilled in the art that these specific details
are not required in every case and that, in some instances, well-known structures
and components are shown in block diagram form for clarity of presentation.
[0010] This disclosure relates generally to providing or participating in authorized shared
access between two or more wireless communications systems, also referred to as wireless
communications networks. In various embodiments, the techniques and apparatus may
be used for wireless communication networks such as code division multiple access
(CDMA) networks, time division multiple access (TDMA) networks, frequency division
multiple access (FDMA) networks, orthogonal FDMA (OFDMA) networks, single-carrier
FDMA (SC-FDMA) networks, LTE networks, GSM networks, 5
th Generation (5G) or new radio (NR) networks, as well as other communications networks.
As described herein, the terms "networks" and "systems" may be used interchangeably.
An OFDMA network may implement a radio technology such as evolved UTRA (E-UTRA), IEEE
802.11, IEEE 802.16, IEEE 802.20, flash-OFDM and the like. UTRA, E-UTRA, and
Global System for Mobile Communications (GSM) are part of universal mobile telecommunication
system (UMTS). In particular, long term evolution (LTE) is a release of UMTS that
uses E-UTRA. UTRA, E-UTRA, GSM, UMTS and LTE are described in documents provided from
an organization named "3rd Generation Partnership Project" (3GPP), and cdma2000 is
described in documents from an organization named "3rd Generation Partnership Project
2" (3GPP2). These various radio technologies and standards are known or are being
developed. For example, the 3rd Generation Partnership Project (3GPP) is a collaboration
between groups of telecommunications associations that aims to define a globally applicable
third generation (3G) mobile phone specification. 3GPP long term evolution (LTE) is
a 3GPP project which was aimed at improving the universal mobile telecommunications
system (UMTS) mobile phone standard. The 3GPP may define specifications for the next
generation of mobile networks, mobile systems, and mobile devices. The present disclosure
is concerned with the evolution of wireless technologies from LTE, 4G, 5G, NR, and
beyond with shared access to wireless spectrum between networks using a collection
of new and different radio access technologies or radio air interfaces.
[0011] In particular, 5G networks contemplate diverse deployments, diverse spectrum, and
diverse services and devices that may be implemented using an OFDM-based unified,
air interface. In order to achieve these goals, further enhancements to LTE and LTE-A
are considered in addition to development of the new radio technology for 5G NR networks.
The 5G NR will be capable of scaling to provide coverage (1) to a massive Internet
of things (loTs) with an ultra-high density (e.g., ~1M nodes/km
2), ultra-low complexity (e.g., ~10s of bits/sec), ultra-low energy (e.g., ~10+ years
of battery life), and deep coverage with the capability to reach challenging locations;
(2) including mission-critical control with strong security to safeguard sensitive
personal, financial, or classified information, ultra-high reliability (e.g., ~99.9999%
reliability), ultra-low latency (e.g., - 1 ms), and users with wide ranges of mobility
or lack thereof; and (3) with enhanced mobile broadband including extreme high capacity
(e.g., - 10 Tbps/km
2), extreme data rates (e.g., multi-Gbps rate, 100+ Mbps user experienced rates), and
deep awareness with advanced discovery and optimizations.
[0012] The 5G NR may be implemented to use optimized OFDM-based waveforms with scalable
numerology and transmission time interval (TTI); having a common, flexible framework
to efficiently multiplex services and features with a dynamic, low-latency time division
duplex (TDD)/frequency division duplex (FDD) design; and with advanced wireless technologies,
such as massive multiple input, multiple output (MIMO), robust millimeter wave (mmWave)
transmissions, advanced channel coding, and device-centric mobility. Scalability of
the numerology in 5G NR, with scaling of subcarrier spacing, may efficiently address
operating diverse services across diverse spectrum and diverse deployments. For example,
in various outdoor and macro coverage deployments of less than 3GHz FDD/TDD implementations,
subcarrier spacing may occur with 15 kHz, for example over 1, 5, 10, 20 MHz, and the
like bandwidth. For other various outdoor and small cell coverage deployments of TDD
greater than 3 GHz, subcarrier spacing may occur with 30 kHz over 80/100 MHz bandwidth.
For other various indoor wideband implementations, using a TDD over the unlicensed
portion of the 5 GHz band, the subcarrier spacing may occur with 60 kHz over a 160
MHz bandwidth. Finally, for various deployments transmitting with mmWave components
at a TDD of 28 GHz, subcarrier spacing may occur with 120 kHz over a 500MHz bandwidth.
[0013] The scalable numerology of the 5G NR facilitates scalable TTI for diverse latency
and quality of service (QoS) requirements. For example, shorter TTI may be used for
low latency and high reliability, while longer TTI may be used for higher spectral
efficiency. The efficient multiplexing of long and short TTIs to allow transmissions
to start on symbol boundaries. 5G NR also contemplates a self-contained integrated
subframe design with uplink/downlink scheduling information, data, and acknowledgement
in the same subframe. The self-contained integrated subframe supports communications
in unlicensed or contention-based shared spectrum, adaptive uplink/downlink that may
be flexibly configured on a per-cell basis to dynamically switch between uplink and
downlink to meet the current traffic needs.
[0014] Various other aspects and features of the disclosure are further described below.
It should be apparent that the teachings herein may be embodied in a wide variety
of forms and that any specific structure, function, or both being disclosed herein
is merely representative and not limiting. Based on the teachings herein one of an
ordinary level of skill in the art should appreciate that an aspect disclosed herein
may be implemented independently of any other aspects and that two or more of these
aspects may be combined in various ways. For example, an apparatus may be implemented
or a method may be practiced using any number of the aspects set forth herein. In
addition, such an apparatus may be implemented or such a method may be practiced using
other structure, functionality, or structure and functionality in addition to or other
than one or more of the aspects set forth herein. For example, a method may be implemented
as part of a system, device, apparatus, and/or as instructions stored on a computer
readable medium for execution on a processor or computer. Furthermore, an aspect may
comprise at least one element of a claim.
[0015] FIG. 1 is a block diagram illustrating 5G network 100 including various base stations
and UEs configured according to aspects of the present disclosure. The 5G network
100 includes a number of base stations 105 and other network entities. A base station
may be a station that communicates with the UEs and may also be referred to as an
evolved node B (eNB), a next generation eNB (gNB), an access point, and the like.
Each base station 105 may provide communication coverage for a particular geographic
area. In 3GPP, the term "cell" can refer to this particular geographic coverage area
of a base station and/or a base station subsystem serving the coverage area, depending
on the context in which the term is used.
[0016] A base station may provide communication coverage for a macro cell or a small cell,
such as a pico cell or a femto cell, and/or other types of cell. 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, such as a pico cell, would generally cover a relatively smaller geographic
area and may allow unrestricted access by UEs with service subscriptions with the
network provider. A small cell, such as a femto cell, would also generally cover a
relatively small geographic area (e.g., a home) and, in addition to unrestricted access,
may also 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). A base station for a macro cell may be referred to as a macro base station.
A base station for a small cell may be referred to as a small cell base station, a
pico base station, a femto base station or a home base station. In the example shown
in FIG. 1, the base stations 105d and 105e are regular macro base stations, while
base stations 105a-105c are macro base stations enabled with one of 3 dimension (3D),
full dimension (FD), or massive MIMO. Base stations 105a-105c take advantage of their
higher dimension MIMO capabilities to exploit 3D beamforming in both elevation and
azimuth beamforming to increase coverage and capacity. Base station 105f is a small
cell base station which may be a home node or portable access point. A base station
may support one or multiple (e.g., two, three, four, and the like) cells.
[0017] The 5G network 100 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.
[0018] The UEs 115 are dispersed throughout the wireless network 100, and each UE may be
stationary or mobile. A UE may also be referred to as a terminal, a mobile station,
a subscriber unit, a station, or the like. A UE may be a cellular phone, a personal
digital assistant (PDA), a wireless modem, a wireless communication device, a handheld
device, a tablet computer, a laptop computer, a cordless phone, a wireless local loop
(WLL) station, or the like. In one aspect, a UE may be a device that includes a Universal
Integrated Circuit Card (DICC). In another aspect, a UE may be a device that does
not include a DICe. In some aspects, UEs that do not include UICCs may also be referred
to as internet of everything (IoE) devices. UEs 115a-115d are examples of mobile smart
phone-type devices accessing 5G network 100 A UE may also be a machine specifically
configured for connected communication, including machine type communication (MTC),
enhanced MTC (eMTC), narrowband IoT (NB-IoT) and the like. UEs 115e-115k are examples
of various machines configured for communication that access 5G network 100. A UE
may be able to communicate with any type of the base stations, whether macro base
station, small cell, or the like. In FIG. 1, a lightning bolt (e.g., communication
links) indicates wireless transmissions between a UE and a serving base station, which
is a base station designated to serve the UE on the downlink and/or uplink, or desired
transmission between base stations, and backhaul transmissions between base stations.
[0019] In operation at 5G network 100, base stations 105a-105c serve UEs 115a and 115b using
3D beamforming and coordinated spatial techniques, such as coordinated multipoint
(CoMP) or multi-connectivity. Macro base station 105d performs backhaul communications
with base stations 105a-105c, as well as small cell, base station 105f. Macro base
station 105d also transmits multicast services which are subscribed to and received
by UEs 115c and 115d. Such multicast services may include mobile television or stream
video, or may include other services for providing community information, such as
weather emergencies or alerts, such as Amber alerts or gray alerts.
[0020] 5G network 100 also support mission critical communications with ultra-reliable and
redundant links for mission critical devices, such UE 115e, which is a drone. Redundant
communication links with UE 115e include from macro base stations 105d and 105e, as
well as small cell base station 105f. Other machine type devices, such as UE 115f
(thermometer), UE 115g (smart meter), and UE 115h (wearable device) may communicate
through 5G network 100 either directly with base stations, such as small cell base
station 105f, and macro base station 105e, or in multi-hop configurations by communicating
with another user device which relays its information to the network, such as UE 115f
communicating temperature measurement information to the smart meter, UE 115g, which
is then reported to the network through small cell base station 105f. 5G network 100
may also provide additional network efficiency through dynamic, low-latency TDD/FDD
communications, such as in a vehicle-to-vehicle (V2V) mesh network between UEs 115i-115k
communicating with macro base station 105e.
[0021] FIG. 2 shows a block diagram of a design of a base station 105 and a UE 115, which
may be one of the base station and one of the UEs in FIG. 1. At the base station 105,
a transmit processor 220 may receive data from a data source 212 and control information
from a controller/processor 240. The control information may be for the PBCH, PCFICH,
PHICH, PDCCH, EPDCCH, MPDCCH etc. The data may be for the PDSCH, etc. The transmit
processor 220 may process (e.g., encode and symbol map) the data and control information
to obtain data symbols and control symbols, respectively. The transmit processor 220
may also generate reference symbols, e.g., for the primary synchronization signal
(PSS), secondary synchronization signal (SSS), and cell-specific reference signal.
A transmit (TX) multiple-input multiple-output (MIMO) processor 230 may perform spatial
processing (e.g., precoding) on the data symbols, the control symbols, and/or the
reference symbols, if applicable, and may provide output symbol streams to the modulators
(MODs) 232a through 232t. Each modulator 232 may process a respective output symbol
stream (e.g., for OFDM, etc.) to obtain an output sample stream. Each modulator 232
may further process (e.g., convert to analog, amplify, filter, and upconvert) the
output sample stream to obtain a downlink signal. Downlink signals from modulators
232a through 232t may be transmitted via the antennas 234a through 234t, respectively.
[0022] At the UE 115, the antennas 252a through 252r may receive the downlink signals from
the base station 105 and may provide received signals to the demodulators (DEMODs)
254a through 254r, respectively. Each demodulator 254 may condition (e.g., filter,
amplify, downconvert, and digitize) a respective received signal to obtain input samples.
Each demodulator 254 may further process the input samples (e.g., for OFDM, etc.)
to obtain received symbols. A MIMO detector 256 may obtain received symbols from all
the demodulators 254a through 254r, perform MIMO detection on the received symbols
if applicable, and provide detected symbols. A receive processor 258 may process (e.g.,
demodulate, deinterleave, and decode) the detected symbols, provide decoded data for
the UE 115 to a data sink 260, and provide decoded control information to a controller/processor
280.
[0023] On the uplink, at the UE 115, a transmit processor 264 may receive and process data
(e.g., for the PUSCH) from a data source 262 and control information (e.g., for the
PUCCH) from the controller/processor 280. The transmit processor 264 may also generate
reference symbols for a reference signal. The symbols from the transmit processor
264 may be precoded by a TX MIMO processor 266 if applicable, further processed by
the modulators 254a through 254r (e.g., for SC-FDM, etc.), and transmitted to the
base station 105. At the base station 105, the uplink signals from the UE 115 may
be received by the antennas 234, processed by the demodulators 232, detected by a
MIMO detector 236 if applicable, and further processed by a receive processor 238
to obtain decoded data and control information sent by the UE 115. The processor 238
may provide the decoded data to a data sink 239 and the decoded control information
to the controller/processor 240.
[0024] The controllers/processors 240 and 280 may direct the operation at the base station
105 and the UE 115, respectively. The controller/processor 240 and/or other processors
and modules at the base station 105 may perform or direct the execution of various
processes for the techniques described herein. The controllers/processor 280 and/or
other processors and modules at the UE 115 may also perform or direct the execution
of the functional blocks illustrated in FIGs. 4, 7, and 8, and/or other processes
for the techniques described herein. The memories 242 and 282 may store data and program
codes for the base station 105 and the UE 115, respectively. A scheduler 244 may schedule
UEs for data transmission on the downlink and/or uplink.
[0025] Wireless communications systems operated by different network operating entities
(e.g., network operators) may share spectrum. In some instances, a network operating
entity may be configured to use an entirety of a designated shared spectrum for at
least a period of time before another network operating entity uses the entirety of
the designated shared spectrum for a different period of time. Thus, in order to allow
network operating entities use of the full designated shared spectrum, and in order
to mitigate interfering communications between the different network operating entities,
certain resources (e.g., time) may be partitioned and allocated to the different network
operating entities for certain types of communication.
[0026] For example, a network operating entity may be allocated certain time resources reserved
for exclusive communication by the network operating entity using the entirety of
the shared spectrum. The network operating entity may also be allocated other time
resources where the entity is given priority over other network operating entities
to communicate using the shared spectrum. These time resources, prioritized for use
by the network operating entity, may be utilized by other network operating entities
on an opportunistic basis if the prioritized network operating entity does not utilize
the resources. Additional time resources may be allocated for any network operator
to use on an opportunistic basis.
[0027] Access to the shared spectrum and the arbitration of time resources among different
network operating entities may be centrally controlled by a separate entity, autonomously
determined by a predefined arbitration scheme, or dynamically determined based on
interactions between wireless nodes of the network operators.
[0028] In some cases, UE 115 and base station 105 may operate in a shared radio frequency
spectrum band, which may include licensed or unlicensed (e.g., contention-based) frequency
spectrum. In an unlicensed frequency portion of the shared radio frequency spectrum
band, UEs 115 or base stations 105 may traditionally perform a medium-sensing procedure
to contend for access to the frequency spectrum. For example, UE 115 or base station
105 may perform a listen before talk (LBT) procedure such as a clear channel assessment
(CCA) prior to communicating in order to determine whether the shared channel is available.
A CCA may include an energy detection procedure to determine whether there are any
other active transmissions. For example, a device may infer that a change in a received
signal strength indicator (RSSI) of a power meter indicates that a channel is occupied.
Specifically, signal power that is concentrated in a certain bandwidth and exceeds
a predetermined noise floor may indicate another wireless transmitter. A CCA also
may include detection of specific sequences that indicate use of the channel. For
example, another device may transmit a specific preamble prior to transmitting a data
sequence. In some cases, an LBT procedure may include a wireless node adjusting its
own backoff window based on the amount of energy detected on a channel and/or the
acknowledge/negative-acknowledge (ACK/NACK) feedback for its own transmitted packets
as a proxy for collisions.
[0029] Use of a medium-sensing procedure to contend for access to an unlicensed shared spectrum
may result in communication inefficiencies. This may be particularly evident when
multiple network operating entities (e.g., network operators) are attempting to access
a shared resource. In 5G network 100, base stations 105 and UEs 115 may be operated
by the same or different network operating entities. In some examples, an individual
base station 105 or UE 115 may be operated by more than one network operating entity.
In other examples, each base station 105 and UE 115 may be operated by a single network
operating entity. Requiring each base station 105 and UE 115 of different network
operating entities to contend for shared resources may result in increased signaling
overhead and communication latency.
[0030] FIG. 3 is a block diagram illustrating a wireless communication system 300 including
base stations that use directional wireless beams. The wireless communication system
300 may be an example of the wireless communication system 100 discussed with reference
to FIG. 1. The wireless communication system 300 includes a serving base station 305
and a target base station 310. Coverage areas 315, 320 may be defined for their respective
base stations 305, 310. The serving base station 305 and the target base station 310
may be examples of the base stations 105 described with reference to FIG. 1. As such,
features of the base stations 305, 310 may be similar to those of the base stations
105.
[0031] The serving base station 305 and the target base station 310 may communicate via
a backhaul link 325. The backhaul link 325 may be a wired backhaul link or a wireless
backhaul link. The backhaul link 325 may be configured to communicate data and other
information between the serving base station 305 and the target base station 310.
The backhaul link 325 may be an example of the backhaul links 134 described in reference
to FIG. 1.
[0032] The serving base station 305 may establish a communication link 330 with a UE 115.
The communication link 330 may be an example of the communication links 125 described
with reference to FIG. 1. One characteristic of UEs 115 in a wireless communication
system 300 is that the UEs 115 may be mobile. Because UEs 115 may change their geophysical
location in the wireless communication system 300, to maintain connectivity, the UE
115 may desire to terminate its connection with the serving base station 305 and establish
a new connection with a target base station 310. For example, as the UE 115 moves,
the UE 115 may approach the limits of the coverage area 315 of the serving base station
305. At the same time, however, the UE 115 may have passed within the coverage area
320 of the target base station 310. In some examples, the UE 115 may determine a mobility
parameter 335 of the UE 115. The mobility parameter 335 may indicate that the UE 115
is at a particular location, traveling in a particular direction, at a particular
speed, other information related to the mobility of the UE 115, or any combination
thereof. When the UE 115 approaches the limits of the coverage area 315 of the serving
base station 305, a handover procedure of the UE 115 between the serving base station
305 and the target base station 310 may be initiated.
[0033] In some examples of new radio (NR), the target base station 310 may communicate with
UEs 115 via directional wireless communication links 340 (sometimes 5 referred to
as directional wireless beams or directional beams). The directional wireless communication
links 340 may be pointed in a specific direction and provide high-bandwidth links
between the target base station 310 and the UEs 115. Signal processing techniques,
such as beamforming, may be used to coherently combine energy and thereby form the
directional wireless communication links 340. Wireless communication links achieved
through beamforming may be associated with narrow beams (e.g., "pencil beams") that
are highly directional, minimize inter-link interference, and provide high-bandwidth
links between wireless nodes (e.g., base stations, access nodes, UEs etc.). In some
examples, the target base station 310 may operate in millimeter wave (mmWave) frequency
ranges, e.g., 28 GHz, 40 GHz, 60 GHz, etc. In some examples, the directional wireless
communication links 340 are transmitted using frequencies greater than 6 GHz. Wireless
communication at these frequencies may be associated with increased signal attenuation,
e.g., path loss, which may be influenced by various factors, such as temperature,
barometric pressure, diffraction, etc. Dynamic beam-steering and beam-search capabilities
may further support, for example, discovery, link establishment, and beam refinement
in the presence of dynamic shadowing and Rayleigh fading. Additionally, communication
in such mmWave systems may be time division multiplexed, where a transmission may
only be directed to one wireless device at a time due to the directionality of the
transmitted signal.
[0034] Each directional wireless communication link 340 may have a beam width 345. The beam
width 345 for each directional wireless communication link 340 may be different (e.g.,
compare the beam width 345-a of the directional wireless communication link 340-a
to the beam width 345-c of the directional wireless communication link 340-c). The
beam width 345 may related to the size of the phased array antenna used to generate
the directional wireless communication link 340. Different beam widths 345 may be
used by the target base station 310 in different scenarios. For example, a first message
may transmitted/received using a directional wireless beam having a first beam width,
while a second message may be transmitted/received using a directional wireless beam
having a second beam width different than the first beam width. The target base station
310 may generate any number of directional wireless communication links 340 (e.g.,
directional wireless communication link 340-N). The directional wireless communication
links 340 generated by the target base station 310 may be pointed at any geographic
location.
[0035] As a UE 115 moves in the wireless communication system 300, the UE 115 may move out
of the effective range of a particular directional wireless communication link (see,
e.g., directional wireless communication link 340-a). Because of the narrow-beam width
345 of the directional wireless communication links 340, the directional wireless
communication links 340 may provide coverage to a small geographic area. In contract,
an omni-directional wireless communications link radiates energy in all directions
and covers a wide geographic area.
[0036] When a target base station 310 uses directional wireless communication links 340
to establish a communication link with a UE 115, it may further complicate a handover
procedure. In some examples, the handover procedure discussed herein is a non-contention
handover procedure. Control messages exchanged during a handover procedure may have
latency between transmission and receipt. As such, there may be a delay of time between
when a target base station 310 assigns resources to the UE 115 and when the UE 115
may execute an operation using those assigned resources. In some examples, the handover
procedure may have a latency that spans a few tens to hundreds of milli-seconds. Due
to UE mobility, rotation, or signal blockage, channel characteristics of a directional
wireless communication link 340 may change over time. In particular, the channel characteristics
of an assigned directional wireless communication link 340 may change during the delays
of the handover procedure. If a single resource (e.g., a single directional wireless
communication link 340) is assigned during a handover procedure, the handover procedure
may fail due to insufficient signal later in the process. Accordingly, handover procedures
may be adjusted to account for multiple directional wireless beams that may be used
to establish a communication link between the target base station 310 and the UE 115
during a handover procedure.
[0037] In LTE, the UE power headroom report (PHR) control element may be used to report
the power headroom available in the UE to a serving eNB. The power headroom of any
given UE may be given by the following equation:

Where P
CMAX corresponds to the total maximum UE transmit power, P
MAX corresponds to the nominal UE maximum transmit power, MPR corresponds to the maximum
power reduction (MPR) value, and AMPR corresponds to the additional MPR. In general,
equation (1) identifies the difference between the nominal UE maximum transmit power
and the estimated power for PUSCH transmission per activated serving cell. The eNB
may then use this information for efficient link adaptation and scheduling.
[0038] The current PHR format includes 8 bits octave, in which the power headroom may be
encoded in 6 bits with a reporting range from -23dB to +40dB in steps of 1 dB, while
the remaining 2 bits are reserved. PHR may be transmitted at a subframe when the UE
has uplink resources allocated for new transmissions. The PHR may be estimated over
one subframe with a reporting delay of 0 ms, resulting in power headroom information
being estimated and transmitted in the same subframe. The network may use this reported
value to estimate how much uplink bandwidth a UE can use for a specific subframe.
In general, the more resource blocks the UE is using, the higher the UE transmission
power gets. However, the UE transmission power should not exceed the maximum transmission
power of the UE. Therefore, a given UE would not be able to use much resource block
(bandwidth) for uplink transmissions if it does not have enough power headroom.
[0039] The PHR can be configured either for periodic reporting or event threshold reporting,
such as when the downlink pathloss has changed by a specific threshold amount. For
periodic reporting, a report is triggered at the expiration of the periodic PHR timer,
which can be configured with various values (e.g., between 10 ms and infinity). For
threshold reporting, a PHR is triggered when the path loss changes by the predefined
threshold amount (1, 3, 6, or infinite dB), provided that a second, configurable threshold
reporting timer has also expired. The threshold reporting timer may start when a PHR
has been transmitted and may have various time values (e.g., between 0 and 1000 ms).
The threshold reporting timer also prevents wasting of resources by sending multiple
PHR when a UE is experiencing rapidly changing pathloss conditions.
[0040] As the periodic PHR timer gets shorter, the power headroom can be more accurate.
However, the shorter periodic timer also causes the UE to send more frequent PHR,
thus, expending more transmission power. In order to address this trade-off, PHR reporting
based on the changing pathloss threshold may be configured. In NR, both periodic reporting
and event threshold-based reporting can be baseline as PHR triggering events.
[0041] The pathloss (
PL) at a UE is generally measured from the difference between RSRP measurements and
base station signalled transmission power information (that is transmission power
of cell-specific reference signals (CRS)). In legacy LTE which uses omni-directional
transmissions, it can be assumed that the pathloss may change relatively smoothly.
However, in beamforming-based transmissions, because of the narrower bandwidth and
directional nature of the beams, the measured pathloss may suddenly fluctuate with
more frequent blockage as well as serving beam changes.
[0042] Blockage (NLOS- no line of sight) can be of greater significance in NR beamformingbased
transmissions than in legacy LTE omni-directional transmissions. The directional line
of sight (LOS) component accounts for a sizable percentage of the received power,
and, thus, is a large part of reliable beamforming-based transmissions. LOS obstruction
by objects such as buildings, brick and even human could lead to increased signal
outages.
[0043] To handle blockage in beamforming-based transmissions, the network can trigger serving
beam changes to change the serving beam based on the UE feedback of measured beam
quality. A serving beam change may involve a sudden drop or rise in the received reference
signal receive power (RSRP), reflecting the changes in pathloss and beamforming gain.
The serving beam change may be based on a beam measurement event configured by a base
station or on a beam measurement report from the UE. For the beam measurement event,
the quality of another beam may become better than the serving beam by at least a
threshold amount. The UE may change the serving beam when the RSRP of the target beam
is higher than the serving beam. In the beam measurement report method, the base station
decides the serving beam based on the measurement report and identifies the change
of the serving beam to the UE. Before the beam change occurs to the target beam, the
UE estimates the pathloss of the previous beam, while after the beam change, the UE
will measure pathloss on the new serving beam.
[0044] In NR mmWave deployments, special issues may arise when applying legacy power control
procedures. For example, beam quality may fluctuate more quickly, which may add uncertainty
to the knowledge of available power at the UE side. Thus, during power adjustment,
the serving beam pair may be changed quickly due to beam blockage. The current standards
suggest a beam-specific power control, even though the legacy systems provide a UE--based
power control. Such suggested beam-specific power control defines the possibility
for beam-specific open and closed loop parameters. A given base station may be aware
of the power headroom differences for different waveforms, if the UE can be configured
for both waveforms.
[0045] In legacy LTE, measured pathloss (
PL) is determined according to the following equation:

Where the layer 3 filtered RSRP is based on CRS and ReferenceSignalPower is provided
by higher layers via system information broadcasts (e.g., SIB2). Several special issues
may arise in NR deployments. For example, NR deployments may not typically transmit
L3 CRS at a rate that would be frequent enough to provide RSRP quickly enough to address
the fast beam changes. The more frequent reference signals in NR deployments include
NR synchronization signals (NR-SS) and channel state information (CSI) reference signals
(CSI-RS). NR-SS have been suggested for 5G NR networks as synchronization signals
similar to the PSS/SSS/PBCH of LTE networks. As currently considered, NR-SS may be
an always-on periodic signal. Thus, pathloss measurement in NR deployments could rely
on either NR-SS or CSI-RS for performing the beam-specific RSRP measurements, instead
of CRS. NR-SS and CSI-RS may have different beamforming gain, and CSI-RS may not even
always be on. Therefore, in beam-specific power control operations, the issue arises
over the use of L3 filtered beam RSRP vs. L1 filtered beam quality.
[0046] Additionally, in NR deployments, downlink beamforming gain may be largely different
from uplink beamforming gain. This could occur because downlink and uplink transmissions
may use different antenna panels. Moreover, different beam patterns may be used to
adapt different interference environments for downlink and uplink transmissions, as
well as circumstances in which the downlink associated base station may be different
from the uplink associated base station (which may also be an issue in some LTE networks).
[0047] As noted above, legacy PHR reporting in LTE is generally UE-specific. However, the
standards for NR network deployments has suggested that beam-specific power control
be used. For example, during power adjustment, the beam pair may be changed (beam
change) due to beam blockage. A UE-specific approach may not result in accurate operations,
because a base station may not be certain which beam's PHR the UE is reporting when
beam changing occurs. It has further been observed that, in beamforming deployments,
such as NR mmWave operations, a beam energy change of up to 15 dB may be experienced
between the best beam and the next best beam of the set of serving beams. Thus, relying
on the PHR of the wrong beam in scheduling and link adaptation may result in a diminished
communications experience. Moreover, considering such a large difference in beam energy,
PHR reporting and event triggering become coupled issues, as the PHR event trigger
in legacy LTE systems is also not beam-specific. Accordingly, various aspects of the
present disclosure are directed to power control procedures having beam-specific periodic
PHR reporting plus UE-specific event threshold PHR reporting.
[0048] FIG. 4 is a block diagram illustrating example blocks executed to implement an un-claimed
aspect of the present disclosure. The example blocks will also be described with respect
to UE 115 as illustrated in FIG. 9. FIG. 9 is a block diagram illustrating UE 115
configured according to one aspect of the present disclosure. UE 115 includes the
structure, hardware, and components as illustrated for UE 115 of FIG. 2. For example,
UE 115 includes controller/processor 280, which operates to execute logic or computer
instructions stored in memory 282, as well as controlling the components of UE 115
that provide the features and functionality of UE 115. UE 115, under control of controller/processor
280, transmits and receives signals via wireless radios 900a-r and antennas 252a-r.
Wireless radios 900a-r includes various components and hardware, as illustrated in
FIG. 2 for eNB 105, including modulator/demodulators 254a-r, MIMO detector 256, receive
processor 258, transmit processor 264, and TX MIMO processor 266.
[0049] At block 400, a UE determines a beam-specific periodic PHR in response to expiration
of a first reporting timer. For example, UE 115, under control of controller/processor
280, executes periodic timer 903, stored in memory 282. Periodic timer 903 counts
between times when UE 115 will send a beam-specific PHR to the serving base station.
On expiration of periodic timer 903, UE 115 executes power headroom logic 901, stored
in memory 282. The execution environment of power headroom logic measures the power
headroom associated with the currently serving one or more beams. UE 115 then executes
PHR generator 902 to generate the periodic PHR. At block 401, the UE transmits the
beam-specific PHR to the serving base station. With the periodic reporting, when the
periodic timer expires, UE 115 would report a beam-specific periodic PHR via wireless
radios 900a-r and antennas 252a-r. This may be accomplished in a number of ways. For
example, UE 115 may determine the power headroom for each of the serving beams and
transmit the aggregate PHR that includes the power headroom for all of the beams.
Alternatively, UE 115 may be scheduled by the base station to measure and report the
PHR for each of the serving beams in different slots or at different times.
[0050] At block 402, the UE detects a report trigger event. UE 115, under control of controller/processor
280, accesses event triggers 905, stored in memory 282. UE 115 may determine what
events will trigger the event-trigger PHR. The report trigger event may include detecting
the change in pathloss of the current serving beam by a predetermined amount. For
example, UE 115 would execute measurement logic 906, stored in memory 282, to measure
and maintain the pathloss of the serving beam. Additionally, a report trigger event
may be defined for beam changes. Thus, UE would execute beam change logic 907, stored
in memory 282, to keep track of any beam changes that may occur at UE 115. At block
403, the UE determines a UE-specific trigger PHR in response to the report triggering
event and expiration of a second timer, and, at block 404, transmits the UE-specific
trigger PHR to the serving base station. If a pathloss change is detected using measurement
logic 906, beyond that predetermined amount, as may be stored at event triggers 905,
or a beam change occurs, as tracked by the execution environment of beam change logic
907, UE 115 accesses threshold reporting timer 904, stored in memory 282, to determine
whether threshold reporting timer 904 has expired. If both the event is detected and
threshold reporting timer 904 have expired, UE 115 will determine a UE-specific PHR
by executing PHR generator 902. The UE- specific PHR could be either for only the
current serving beam or could be for all of the serving beams. UE 115 will then transmit
the UE-specific PHR via wireless radios 900a-r and antennas 252a-r.
[0051] FIG. 5 is a block diagram illustrating a base station 105 communicating with UE 115
using mmWave beamforming, in which base station 105 and UE 115 are configured according
to un-claimed aspects of the present disclosure. UE 115 is in motion within coverage
area 500 of base station 105. In serving UE 115, base station 105 beam forms a set
of serving beams 501. While each serving beams 501 is a serving beam, there may be
only one of serving beams 501-a - 501-d actually serving UE 115 at a given time. As
UE 115 moves across coverage area 500, the quality of the current serving beam may
change or the current serving beam may be blocked, causing UE 115 to beam change to
the best of the set of serving beams 501. As noted, the because of the beamforming
by base station 105, there may be a beam energy change of up to 15dB between the best
beam and the next best beam of the set of serving beams 501. In one example of operation,
after expiration of the periodic PHR timer, UE 115 may determine power headroom and
transmit a PHR to base station 105.
[0052] In one possible scenario, UE 115 may reuse the legacy LTE PHR reporting by reporting
only one periodic PHR for current serving beam. For example, if, at the expiration
of the periodic PHR timer, UE 115 is currently served by serving beam 501-b, UE 115
will calculate the power headroom of serving beam 501-b and transmit it in a PHR to
base station 105. Base station 105 estimate the other beams' PHR based on an estimation
for beamforming gain difference in UE 115, based on the same nominal UE maximum transmit
power (P
MAX). However, in such a possible scenario, the serving beam may change over the periodic
PHR timer. Therefore, base station 105 may not have a timely PHR for the alternative
beams.
[0053] FIG. 6A is a block diagram illustrating base station 105 and UE 115 configured according
to an un-claimed aspect of the present disclosure. When UE 115 transmits the periodic
PHR to base station 105 (FIG. 5), it may transmit one periodic PHR that includes the
power headroom information of all serving beams. A typical PHR is formatted as an
octet, with a 6-bit power headroom and two reserved bit. When transmitting one periodic
PHR that includes power headroom information for all of the serving beams, an aggregated
PHR 600 is generated. UE 115 aggregates the 6-bit power headroom information 601 for
beam #1 with the 6-bit power headroom information 602 for beam #2 into aggregated
PHR 600. The two reserved bits may further be used by UE 115 to identify which of
the beams the PHR goes with. Thus, beam index 603 identifies beam #1, while beam index
604 identifies beam #2. Base station 105 would then be able to identify which beam
the PHR information belongs to.
[0054] FIG. 6B is a block diagram illustrating base station 105 and UE 115 configured according
to another un-claimed aspect of the present disclosure. PHR reporting according to
the aspect illustrated in FIG. 6B reuses the legacy LTE. However, base station 105
configures UE 115 to measure and report PHR at different a period and/or at an offset
for the different beams of the set of serving beams. UE 115 is configured to report
PHR 605, including the power headroom information 607 for beam #1, at slot 1, and
is configured to report PHR 606, including power headroom information 608 for beam
#2, at slot
N. Therefore, over the course of transmissions by UE 115, base station 105 will receive
the PHR for each of the beams in the set of serving beams.
[0055] It should be noted that, such aspects may only work for periodic reference signals,
such as CSI-RS and NR-SS. Moreover, a new periodical PHR trigger may be configured
for a set of beams, where each configuration includes both a period and/or an offset
for determining and reporting the PHR for each serving beam in different reports or
slots.
[0056] Referring back to FIG. 5, an additional aspect that may be illustrated by FIG. 5
include PHR reporting based on an event trigger. For example, an event trigger may
be the change in pathloss of a serving beam that exceeds a predetermined threshold.
In the presently described example, the legacy LTE procedures are reused by UE 115
in reporting one PHR when the measured pathloss of the current serving beam exceeds
the predetermined threshold and expiration of a threshold reporting timer. As noted,
the threshold reporting timer prevents UE 115 from reporting PHR too frequently when
UE 115 is experiencing rapid changes in pathloss. Thus, when UE 115 calculates a change
in pathloss of the current serving beam, beam 501-a, that exceeds the threshold level,
UE 115 checks threshold reporting timer to determine if the timer has expired. If
the timer has expired, UE 115 will calculate the power headroom and generate the PHR
to report to base station 105. Otherwise, if the threshold reporting timer has not
expired, UE 115 will not generate a PHR, but, instead, continue operations. If, when
the threshold reporting timer does expire, and the measured pathloss change at the
expiration still exceeds the threshold level, UE 115 will generate and transmit a
PHR for base station 105.
[0057] In the currently-described example aspect, the pathloss threshold and threshold reporting
timer may apply across the set of serving beams 501. Thus, in the presently-described
aspect, the pathloss threshold and threshold reporting timer will be common to UE
115 for all serving beams. For example, if UE 115 experiences an NLOS blockage of
serving beam 501-a and determines to beam change to serving beam 501-b, threshold
reporting timer will continue without reset, in addition to the same pathloss threshold
and any other protocol variable being the same for serving beam 501-b.
[0058] With event-trigger PHR procedures, UE 115 may report a single PHR to base station
105, as in the legacy LTE procedures. The single PHR implies that the event-triggered
PHR calculated and transmitted by UE 115 to base station 105 does not distinguish
beams. The beam-specific PHRs would, instead, be reported by UE 115 during the periodic
PHR reporting. Two sub-solutions for PHR reporting. Alt-1-a: report just one PHR (same
as LTE). It implies that prohibit PHR does not distinguish beams (assuming that beam-specific
PHR is reported in periodical PHR).
[0059] In an alternative of the presently-described aspect, UE 115 may report a single PHR
to base station 105 that includes the power headroom information for all of the serving
beams. For example, referring back to FIG. 6A, in the presently-described aspect,
aggregated PHR 600 corresponds to the event-trigger PHR, with the power headroom information
601 for beam #1 and the power headroom information 602 for beam #2. Similar to the
periodic PHR procedure described previously for FIG. 6A, event-trigger version of
aggregated PHR 600 includes beam indices 603 and 604 in the reserved 2-bit location
of the PHR octet that identifies to base station 105 which beam power headroom information
601 and 602 applies to.
[0060] As noted, the legacy LTE event-trigger PHR reporting procedures include pathloss
change threshold values ranging from 1, 3. and 6dB. However, aspects of the present
disclosure operated in 5G mmWave deployments may not properly trigger based on the
pathloss changes that may be observed with mmWave beamforming (e.g., approximately
15dB). In order to accommodate the larger potential pathloss change in mmWave beamforming
deployments, aspects of the present disclosure may change the legacy pathloss threshold
to at least 15dB. Thus, referring back to FIG. 5, if UE 115 detects a pathloss on
serving beam 501-a that meets the 15dB pathloss threshold, UE 115 will trigger calculation
and transmission of an event-trigger PHR for base station 105.
[0061] Additional aspects of the present disclosure may add new trigger events to the event-trigger
PHR reporting procedures. In one such example, serving beam change may be identified
as an event trigger for UE 115. Referring again to FIG. 5, in the presently-described
additional aspect, UE 115 experiences NLOS blockage of current serving beam 501-a
and selects to beam change to beam 501-b. Upon selecting to beam change, UE 115 checks
the threshold reporting timer to determine if it has expired. If so, then UE 115 will
calculate the power headroom on beam 501-b and generate a event-trigger PHR for base
station 105 with the power headroom information.
[0062] FIG. 6C is a block diagram illustrating base station 105 and UE 115 configured according
to another aspect of the present disclosure. When UE 115 selects the beam change to
serving beam 501-b (FIG. 5), it calculates power headroom information 610 for serving
beam 501-b and includes it in event-trigger PHR 609. In order to inform base station
105 which beam power headroom information 610 corresponds to, the 2-bit reserve of
the PHR octet may include beam index 611, which identifies serving beam 501-b. Because
the beam change is configured as an event trigger, the threshold reporting timer and
protocol variables should be reset when such an event is detected. Thus, the timers
and protocol variables of the presently-described example aspect are maintained per
beam and not per UE.
[0063] It should be noted that, in the presently described example, the pathloss threshold
value may not need to be extended to the higher potential pathloss change that may
be experienced in mmWave beamforming. Such high levels of potential pathloss are generally
associated with the different beams of the set of serving beams. Thus, when beam change
is already an event trigger, the pathloss threshold value may not need to reflect
the larger value for mmWave beamforming. In such aspects base station 105 and UE 115
would have no ambiguity on the serving beam, as the beam switch is robust.
[0064] It should be noted that additional or alternative aspect may provide for beam-specific
event-trigger PHR from UE 115, where base station 105 configures UE 115 to monitor
multiple serving beam's PHRs in different slots. In such aspects, base station 105
would receive event-trigger PHR for additional serving beams in the different configured
slots. This multiple serving beam PHR procedure may work efficiently using periodic
CSI-RS or NR-SS. Such aspects would include new event-trigger PHR configurations for
a set of beams, where each includes different periods and/or offsets. Separate timers
and protocol variables may be maintained per beam, without necessity to extend the
pathloss threshold range to the higher levels observed in mmWave beamforming.
[0065] The various aspects of the present disclosure provide for power control processes
for mn-iwave beamforming deployments including both periodic PHR reporting and event-trigger
PHR reporting. Pathloss estimation is performed for determining certain trigger events.
However, as indicated previously, the nature of mmWave beamforming potentially creates
issues in extending the legacy LTE PHR reporting procedures, as the omni-directional
CRS may not be adequate to efficiently measure or estimate pathloss in rapidly changing
directional beams.
[0066] Additional aspects of the present disclosure may provide for reference signals that
may address the issues in mmWave beams. In one example implementation, CSI-RS are
configured as the baseline reference signal for pathloss estimation in mmWave beamforming.
CSI-RS may provide more accurate pathloss estimates because the UE would be in a connected-mode
and, thus, calculations on the CSI-RS would include downlink beamforming gain in the
pathloss estimation.
[0067] Further aspects of the present disclosure may additionally provide for NR-SS as the
reference signal for pathloss estimation. If NR-SS may be used in addition to CSI-RS,
a serving base station may indicate which of these reference signals should be used
for pathloss estimation through dedicated signaling.
[0068] FIG. 7 is a block diagram illustrating example blocks executed to implement another
un-claimed aspect of the present disclosure. The example blocks will also be described
with respect to the detail of UE 115 in FIG. 9. At block 700, a UE receives an identification
signal from a serving base station that identifies one or more reference signals for
pathloss measurement. The identification signal received by UE 115 may be included
in power control configuration information received via antennas 252a-r and wireless
radios 900a-r and identify to UE 115 whether CSI-RS or NR-SS are to be used for pathloss
estimation. Such power control configuration information may be signaled at least
semi-statically (e.g., radio resource control (RRC) or media access control (MAC)
control element (MAC-CE)). Due to potential large beamforming gain difference between
different beams, the identification signal may also indicate to the UE which subset
of CSI-RS to measure for pathloss estimation.
[0069] It should be noted that the indicated CSI-RS may be periodic, semi-periodic, or aperiodic
CSI-RS.
[0070] At block 701, the UE measures a pathloss on the one or more reference signals identified
by the identification signal. For example, UE 115 executes measurement logic 906 to
measure the pathloss of the identified reference signals (NR-SS, CSI-RS, or a designated
subset of CSI-RS) The UE, at block 702, compares the measured pathloss to a threshold
trigger value. Under control of controller/processor 280, UE 115 compares the measured
pathloss against the threshold trigger value stored at event triggers 905. If the
measured pathloss exceeds the threshold trigger value, then, at block 703, activates
power headroom reporting. Thus, if the measured pathloss exceeds the event trigger,
UE 115 will execute power headroom logic 901 and PHR generator 902 to measure the
power headroom and send the PHR to the serving base station. According to the presently-described
aspect, dedicated signaling is used by the base station to signal UE 115 which reference
signals to use for pathloss estimation in the mmWave beamforming deployment.
[0071] While dedicated signaling may be used to identify the appropriate reference signals
for pathloss estimation, issues may arise based on a mismatch between uplink and downlink
beamforming gain. As indicated above, such a mismatch may occur because downlink and
uplink transmissions use different antenna panels. Different beam patterns may also
be used to adapt different interference environments for downlink and uplink transmissions,
as well as scenarios in which the base station associated with downlink may be different
from the base station associated uplink transmissions.
[0072] To address the mismatch, in one example aspect, the UE may reuse the legacy LTE pathloss
estimation, in which the beam mismatch may be compensated for by the base station
through implementation. While the compensation may improve the mismatch, it may be
difficult for the base station to estimate UE receive beamforming gain if UE receiver
beamforming applies.
[0073] In an additional aspect of the present disclosure, in order to address the mismatch
issue, a beam-specific pathloss offset may be added to the dedicated signaling from
the base station to the UE. Beam-specific pathloss offset corresponds to the downlink
beamforming gain minus the uplink beamforming gain. If UE receiver beamforming is
applied, the UE could add offset attributable to UE receive beamforming gain.
[0074] It should be noted that, in order to address the mismatch between uplink and downlink
beamforming gain, a UE may reuse the legacy LTE pathloss estimation with the UE compensating
for the beam mismatch through implementation. While no specification changes would
be required in such an option, it may be difficult for a UE to estimate the difference
in beamforming gain between uplink and downlink without more detailed signaling exchanges
with the serving base station.
[0075] FIG. 8 is a block diagram illustrating example blocks executed to implement one aspect
of the present disclosure. The example blocks will also be described with respect
to the detail of UE 115 in FIG. 9. At block 800, a UE determines a time period since
a last beam change of one or more serving beams received at the UE from a serving
base station. For example, UE 115 executes beam change logic 907 to determine the
time period since the last beam change. At block 801, the UE measures a pathloss of
a beam-specific layer 3 reference signal on a current serving beam in response to
the time period exceeding a minimum time threshold. When beam changes do not occur
too frequently, use of beam-specific layer 3 reference signals for pathloss estimation
by UE 115 may be sufficient. UE 115, under control of controller/processor 280, would
execute measurement logic 906 to determine the pathloss estimation. At block 802 the
UE measures the pathloss of a beam-specific layer 1 reference signal on the current
serving beam in response to the time period being below the minimum time threshold.
When beam changing occurs more rapidly, the layer 3 signaling may not occur often
enough to sufficiently provide UE 115 the signal for pathloss estimation. The layer
1 signaling would be preferable in order to address the more frequent and beam-specific
aspects of mmWave transmissions.
[0076] Those of skill in the art would understand that information and signals 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 above description may be represented by voltages, currents,
electromagnetic waves, magnetic fields or particles, optical fields or particles,
or any combination thereof.
[0077] The functional blocks and modules in FIGs. 4, 7, and 8 may comprise processors, electronics
devices, hardware devices, electronics components, logical circuits, memories, software
codes, firmware codes, etc., or any combination thereof.
[0078] Those of skill would further appreciate that the various illustrative logical blocks,
modules, circuits, and algorithm steps described in connection with the disclosure
herein may be implemented as electronic hardware, computer software, or combinations
of both. To clearly illustrate this interchangeability of hardware and software, various
illustrative components, blocks, modules, circuits, and steps have been described
above generally in terms of their functionality. Whether such functionality is implemented
as hardware or software depends upon the particular application and design constraints
imposed on the overall system. Skilled artisans may implement the described functionality
in varying ways for each particular application, but such implementation decisions
should not be interpreted as causing a departure from the scope of the present disclosure.
Skilled artisans will also readily recognize that the order or combination of components,
methods, or interactions that are described herein are merely examples and that the
components, methods, or interactions of the various aspects of the present disclosure
may be combined or performed in ways other than those illustrated and described herein.
[0079] The various illustrative logical blocks, modules, and circuits described in connection
with the disclosure herein may be implemented or performed with a general-purpose
processor, a digital signal processor (DSP), an application specific integrated circuit
(ASIC), a field programmable 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 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, a plurality of microprocessors, one or more microprocessors in conjunction
with a DSP core, or any other such configuration.
[0080] The steps of a method or algorithm described in connection with the disclosure herein
may be embodied directly in hardware, in a software module executed by a processor,
or in a combination of the two. A software module may reside in RAM memory, flash
memory, ROM memory, EPROM memory, EEPROM memory, registers, hard disk, a removable
disk, a CD-ROM, or any other form of storage medium known in the art. An exemplary
storage medium is coupled to the processor such that the processor can read information
from, and write information to, the storage medium. In the alternative, the storage
medium may be integral to the processor. The processor and the storage medium may
reside in an ASIC. The ASIC may reside in a user terminal. In the alternative, the
processor and the storage medium may reside as discrete components in a user terminal.
[0081] In one or more exemplary designs, the functions described may be implemented in hardware,
software, firmware, or any combination thereof. If implemented in software, the functions
may be stored on or transmitted over as one or more instructions or code on a computer-readable
medium. Computer-readable media includes both computer storage media and communication
media including any medium that facilitates transfer of a computer program from one
place to another. Computer-readable storage media may be any available media that
can be accessed by a general purpose or special purpose computer. By way of example,
and not limitation, such computer-readable media can comprise RAM, ROM, EEPROM, CD-ROM
or other optical disk storage, magnetic disk storage or other magnetic storage devices,
or any other 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,
a connection may be 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, or digital subscriber line (DSL), then the
coaxial cable, fiber optic cable, twisted pair, or DSL, are included in the definition
of medium. Disk and disc, as used herein, includes compact disc (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 should also be included within the scope of computer-readable
media.
[0082] As used herein, including in the claims, the term "and/or," when used in a list of
two or more items, means that any one of the listed items can be employed by itself,
or any combination of two or more of the listed items can be employed. For example,
if a composition is described as containing components A, B, and/or C, the composition
can contain A alone; B alone; C alone; A and B in combination; A and C in combination;
B and C in combination; or A, B, and C in combination. Also, as used herein, including
in the claims, "or" as used in a list of items prefaced by "at least one of" indicates
a disjunctive 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 BC or ABC (i.e., A and B and C) or any of these in
any combination thereof.