(19)
(11)EP 3 793 308 A1

(12)EUROPEAN PATENT APPLICATION
published in accordance with Art. 153(4) EPC

(43)Date of publication:
17.03.2021 Bulletin 2021/11

(21)Application number: 18917765.2

(22)Date of filing:  07.05.2018
(51)Int. Cl.: 
H04W 74/08  (2009.01)
H04W 72/04  (2009.01)
(86)International application number:
PCT/JP2018/017679
(87)International publication number:
WO 2019/215802 (14.11.2019 Gazette  2019/46)
(84)Designated Contracting States:
AL AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MK MT NL NO PL PT RO RS SE SI SK SM TR
Designated Extension States:
BA ME
Designated Validation States:
KH MA MD TN

(71)Applicant: FUJITSU LIMITED
Kanagawa 211-8588 (JP)

(72)Inventors:
  • OHTA, Yoshiaki
    Kawasaki-shi, Kanagawa 211-8588 (JP)
  • KAWASAKI, Yoshihiro
    Kawasaki-shi, Kanagawa 211-8588 (JP)
  • ODE, Takayoshi
    Kawasaki-shi, Kanagawa 211-8588 (JP)

(74)Representative: Haseltine Lake Kempner LLP 
Cheapside House 138 Cheapside
London EC2V 6BJ
London EC2V 6BJ (GB)

  


(54)TERMINAL DEVICE, BASE STATION DEVICE, WIRELESS COMMUNICATION SYSTEM, AND SCHEDULING REQUEST METHOD


(57) A terminal device (100) includes a generating unit (111) that generates a buffer status report indicating an amount of data accumulated in a transmission buffer of the terminal device when requesting transmission of data, a transmission control unit (112) that executes a random access procedure for transmitting the buffer status report, and a cancellation control unit (113) that is able to cancel a random access procedure being executed by the transmission control unit (112) when the buffer status report is transmitted using a first wireless resource that has been allocated in advance to the terminal device. The cancellation control unit (113) does not cancel the random access procedure when the buffer status report is transmitted using a second wireless resource provided by the random access procedure.




Description

Field



[0001] The present invention relates to a terminal device, a base station device, a wireless communication system, and a scheduling request method.

Background Art



[0002] traffic of mobile terminals (smartphones and feature phones) accounts for most of network resources. In addition, traffic used by the mobile terminals tends to increase continuously.

[0003] Meanwhile, with the development of Internet of things (IoT) services (for example, transportation systems, smart meters, and monitoring systems for devices and the like), there is a demand to cope with services that have various requirements. Therefore, in the communication standards of the fifth generation mobile communication (5G or new radio (NR)), technologies that realize a higher data rate, a larger capacity, and a lower delay are desired, in addition to the standard technologies of the fourth generation mobile communication (4G) (for example, see Non Patent Documents 1 to 11). As for the 5G communication standards, working groups of the 3GPP (for example, TSG-RAN WG1, TSG-RAN WG2, and the like) have been examining technologies (Non Patent Documents 12 to 39). The first version of the 5G standard specifications defined by the 3GPP has been released.

[0004] As described above, to cope with a wide variety of services, in the 5G, a large number of use cases that are classified into an enhanced mobile broadband (eMBB), a massive machine type communications (MTC), and a ultra-reliable and low latency communication (URLLC) are supposed to be supported.

[0005] In the wireless network, it is necessary to allocate a wireless resource to allow a terminal device to transmit data. Therefore, the terminal device performs a scheduling request procedure with respect to a base station device to which the terminal device is connected. When a physical uplink control channel (PUCCH) resource is allocated to transmit a scheduling request (SR), the terminal device transmits the SR using the PUCCH resource. In other words, a PUCCH is used as a transmission channel for the SR.

[0006] The base station device that has received the SR provides an UL grant (uplink transmission permission) for uplink transmission performed by the terminal device. When the terminal device receives the UL grant, the terminal device reports an amount of data accumulated in a data buffer to the base station device. This report may be referred to as a buffer status report (BSR). The base station device that has received the BSR recognizes the amount of data accumulated in the data buffer of the terminal device, allocates an appropriate amount of an uplink wireless resource to the terminal device, and transmits an UL grant indicating the wireless resource to the terminal device. Consequently, the terminal device transmits uplink data to the base station device using the notified wireless resource. The above-described procedure may be referred to as an SR PUCCH.

[0007] In contrast, when the PUCCH resource is not adequate, the base station device does not allocate a PUCCH resource for the SR to the terminal device in some cases. In this case, the terminal device needs to perform a random access (RA) procedure in order to transmit uplink data. In the RA procedure, four signals are transmitted and received between the terminal device and the base station device. Specifically, messages as described below are transmitted and received.

[0008] Msg1 (from the terminal device to the base station device): including a random access preamble. A random access channel (RACH) is used as a channel.

[0009] Msg2 (from the base station device to the terminal device): including a random access response. A physical downlink shared channel (PDSCH) is used as a channel. Information to be transmitted includes identification information on the random access preamble in Msg1 received by the base station device and an UL grant for a message to be transmitted next using uplink.

[0010] Msg3 (from the terminal device to the base station device): a physical uplink shared channel (PUSCH) is used as a channel. A wireless resource for transmitting Msg3 is notified by the UL grant of Msg2. Further, an identifier of the terminal device is transmitted by Msg3. As a result, the base station device that receives Msg3 is able to identify the terminal device that is performing the RA procedure.

[0011] Msg4 (from the base station device to the terminal device): including an UL grant. The terminal device that receives the UL grant determines that the RA procedure is successful.

[0012] If the RA procedure is successful similarly to the SR PUCCH, the terminal device transmits a BSR using the UL grant of Msg4, receives an UL grant for allocating an appropriate amount of an uplink wireless resource from the base station device, and transmits uplink data. The above-described procedure may be referred to as an SR RACH.

[0013] As a procedure for cancelling the SR RACH, a study is being conducted to cancel the above-described procedure when an UL grant is allocated to a cell-radio network temporary identifier (C-RNTI) and when a media access control (MAC) protocol data unit (PDU) transmitted by the PUSCH includes a BSR that reflects the latest buffer status (data accumulation status) of the terminal device (Non Patent Documents 21 and 39).

Citation List


Non Patent Literature



[0014] 

[Non Patent Document 1] 3GPP TS 36.211 V15.1.0 (2018-03)

[Non Patent Document 2] 3GPP TS 36.212 V15.1.0 (2018-03)

[Non Patent Document 3] 3GPP TS 36.213 V15.1.0 (2018-03)

[Non Patent Document 4] 3GPP TS 36.300 V15.1.0 (2018-03)

[Non Patent Document 5] 3GPP TS 36.321 V15.1.0 (2018-03)

[Non Patent Document 6] 3GPP TS 36.322 V15.0.1 (2018-04)

[Non Patent Document 7] 3GPP TS 36.323 V14.5.0 (2017-12)

[Non Patent Document 8] 3GPP TS 36.331 V15.1.0 (2018-03)

[Non Patent Document 9] 3GPP TS 36.413 V15.1.0 (2018-03)

[Non Patent Document 10] 3GPP TS 36.423 V15.1.0 (2018-03)

[Non Patent Document 11] 3GPP TS 36.425 V14.1.0 (2018-03)

[Non Patent Document 12] 3GPP TS 37.340 V15.1.0 (2018-03)

[Non Patent Document 13] 3GPP TS 38.201 V15.0.0 (2017-12)

[Non Patent Document 14] 3GPP TS 38.202 V15.1.0 (2018-03)

[Non Patent Document 15] 3GPP TS 38.211 V15.1.0 (2018-03)

[Non Patent Document 16] 3GPP TS 38.212 V15.1.1 (2018-04)

[Non Patent Document 17] 3GPP TS 38.213 V15.1.0 (2018-03)

[Non Patent Document 18] 3GPP TS 38.214 V15.1.0 (2018-03)

[Non Patent Document 19] 3GPP TS 38.215 V15.1.0 (2018-03)

[Non Patent Document 20] 3GPP TS 38.300 V15.1.0 (2018-03)

[Non Patent Document 21] 3GPP TS 38.321 V15.1.0 (2018-03)

[Non Patent Document 22] 3GPP TS 38.322 V15.1.0 (2018-03)

[Non Patent Document 23] 3GPP TS 38.323 V15.1.0 (2018-03)

[Non Patent Document 24] 3GPP TS 38.331 V15.1.0 (2018-03)

[Non Patent Document 25] 3GPP TS 38.401 V15.1.0 (2018-03)

[Non Patent Document 26] 3GPP TS 38.410 V0.9.0 (2018-04)

[Non Patent Document 27] 3GPP TS 38.413 V0.8.0 (2018-04)

[Non Patent Document 28] 3GPP TS 38.420 V0.8.0 (2018-04)

[Non Patent Document 29] 3GPP TS 38.423 V0.8.0 (2018-04)

[Non Patent Document 30] 3GPP TS 38.470 V15.1.0 (2018-03)

[Non Patent Document 31] 3GPP TS 38.473 V15.1.1 (2018-04)

[Non Patent Document 32] 3GPP TR 38.801 V14.0.0 (2017-04)

[Non Patent Document 33] 3GPP TR 38.802 V14.2.0 (2017-09)

[Non Patent Document 34] 3GPP TR 38.803 V14.2.0 (2017-09)

[Non Patent Document 35] 3GPP TR 38.804 V14.0.0 (2017-03)

[Non Patent Document 36] 3GPP TR 38.900 V14.3.1 (2017-07)

[Non Patent Document 37] 3GPP TR 38.912 V14.1.0 (2017-06)

[Non Patent Document 38] 3GPP TR 38.913 V14.3.0 (2017-06)

[Non Patent Document 39] R2-1804572, "Miscellaneous corrections", 3GPP TSG RAN WG2 Meeting #101bis, Sanya, China, 16-20 April 2018


Summary


Technical Problem



[0015] However, in the currently-examined procedure of cancelling the SR RACH, there is a problem in that, in some cases, it is uncertain whether cancellation is to be performed. Specifically, in certain scheduling in which a periodic wireless resource is allocated like in semi-persistent scheduling (SPS) in long term evolution-advanced (LTE-A) for example, the terminal device may be able to transmit a BSR even without receiving an UL grant from the base station device. In other words, in some cases, the terminal device may transmit a BSR using an uplink wireless resource that has been allocated in advance. In this case, the UL grant is not used to transmit the BSR, so that the SR RACH is not cancelled. Therefore, even though the BSR is already transmitted, the SR RACH procedure for transmitting a BSR is continued and an unnecessary process is performed.

[0016] The disclosed technology has been made in consideration of the above aspect and has an object to provide a terminal device, a base station device, a wireless communication system, and a scheduling request method that can appropriately cancel a random access procedure.

Solution to Problem



[0017] According to an aspect of an embodiment, a terminal device disclosed in the subject application includes: a generating unit that generates, when requesting transmission of data, a buffer status report indicating an amount of data accumulated in a transmission buffer of the terminal device; a transmission control unit that executes a random access procedure for transmitting the buffer status report; and a cancellation control unit that is able to cancel, when the buffer status report is transmitted using a first wireless resource that is allocated in advance to the terminal device, a random access procedure being executed by the transmission control unit, wherein the cancellation control unit does not cancel the random access procedure when the buffer status report is transmitted using a second wireless resource that is provided by the random access procedure.

Advantageous Effects of Invention



[0018] According to an aspect of the terminal device, the base station device, the wireless communication system, and the scheduling request method disclosed in the subject application, there is an advantage such that a random access procedure is appropriately canceled.

Brief Description of Drawings



[0019] 

FIG. 1 is a block diagram illustrating a configuration of a terminal device according to one embodiment.

FIG. 2 is a block diagram illustrating a configuration of a base station device according to one embodiment.

FIG. 3 is a sequence diagram illustrating a concrete example of a scheduling request.

FIG. 4 is a sequence diagram illustrating another concrete example of the scheduling request.

FIG. 5 is a diagram illustrating an example of description of contents in a standard specification document according to one embodiment.


Description of Embodiments



[0020] With reference to the drawings, an embodiment of a terminal device, a base station device, a wireless communication system, and a scheduling request method disclosed in the subject application is described below in detail. Furthermore, the present invention is not limited to the embodiment.

[0021] FIG. 1 is a block diagram illustrating a configuration of a terminal device 100 according to one embodiment. The terminal device 100 illustrated in FIG. 1 includes a processor 110, a memory 120, and a wireless communication unit 130.

[0022] The processor 110 includes, for example, a central processing unit (CPU), a field programmable gate array (FPGA), a digital signal processor (DSP), or the like, and controls the entire terminal device 100. Specifically, the processor 110 includes a buffer status report (BSR) generating unit 111, an uplink (UL) transmission control unit 112, and a cancellation control unit 113.

[0023] The BSR generating unit 111, when executing a scheduling request for requesting uplink transmission, refers to a transmission buffer of the terminal device 100 and recognizes an amount of data to be transmitted through uplink. In other words, the BSR generating unit 111 recognizes an amount of data accumulated in the transmission buffer of the terminal device 100. Then, the BSR generating unit 111 generates a buffer status report (BSR) for reporting the amount of accumulated data.

[0024] The UL transmission control unit 112 controls uplink transmission from the terminal device 100 to a base station device. Specifically, when executing a scheduling request for requesting uplink transmission, the UL transmission control unit 112 determines whether a PUCCH wireless resource for the scheduling request is allocated in advance to the terminal device 100. If the PUCCH wireless resource is allocated, the UL transmission control unit 112 causes the wireless communication unit 130 to transmit the scheduling request using the allocated PUCCH wireless resource. Further, if a periodic wireless resource is allocated in advance to the terminal device 100 for example, the UL transmission control unit 112 may cause the wireless communication unit 130 to transmit the scheduling request and a BSR generated by the BSR generating unit 111, by using the wireless resource.

[0025] In contrast, if the PUCCH wireless resource is not allocated, the UL transmission control unit 112 executes the scheduling request through a random access procedure, and transmits and receives various messages. Specifically, the UL transmission control unit 112 causes the wireless communication unit 130 to transmit a random access preamble using a random access channel (RACH). Then, upon receiving a random access response including identification information on the random access preamble transmitted by the terminal device 100 and an UL grant, the UL transmission control unit 112 causes the wireless communication unit 130 to transmit the identification information on the terminal device 100 using a physical uplink shared channel (PUSCH) allocated by the UL grant. Thereafter, upon receiving an UL grant indicating that the random access procedure is successful, the UL transmission control unit 112 causes the wireless communication unit 130 to transmit the BSR generated by the BSR generating unit 111.

[0026] Meanwhile, the UL transmission control unit 112 notifies the cancellation control unit 113 of messages that are transmitted and received in the random access procedure. If an instruction to cancel the random access procedure is issued by the cancellation control unit 113, the random access procedure being executed is cancelled.

[0027] The cancellation control unit 113 determines whether to cancel the random access procedure that is executed when scheduling is requested, on the basis of contents of messages transmitted and received in the random access procedure and a status of allocation of a wireless resource to the terminal device 100. Specifically, when the BSR is transmitted using a wireless resource, which has been allocated in advance to the terminal device 100, during execution of the random access procedure, the cancellation control unit 113 cancels the random access procedure that is being performed. In other words, when a periodic wireless resource is allocated to the terminal device 100 and the BSR is transmitted using the wireless resource for example, the cancellation control unit 113 cancels the random access procedure even when an UL grant is not received.

[0028] Further, when a BSR is transmitted in response to the UL grant that is included in the random access response during execution of the random access procedure for example, the cancellation control unit 113 determines that the random access procedure is not to be cancelled but to be continued. In other words, when the BSR is transmitted together with the identification information on the terminal device 100 in response to the UL grant that is received during the random access procedure, the cancellation control unit 113 continues the random access procedure to complete reception of a last UL grant.

[0029] The memory 120 includes, for example, a random access memory (RAM), a read only memory (ROM), or the like, and stores therein information used by the processor 110 to perform processes.

[0030] The wireless communication unit 130 performs wireless transmission process, such as digital-to-analog (D/A) conversion and up-conversion, on transmission data generated by the processor 110, and wirelessly transmits the data via an antenna. Further, the wireless communication unit 130 performs wireless reception process, such as down-conversion and analog-to-digital (A/D) conversion, on data that is wirelessly received via the antenna, and outputs the data to the processor 110.

[0031] FIG. 2 is a block diagram illustrating a configuration of a base station device 200 according to one embodiment. The base station device 200 illustrated in FIG. 2 includes a wireless communication unit 210, a processor 220, a memory 230, and a network interface (IF) unit 240.

[0032] The wireless communication unit 210 performs wireless reception process, such as down-conversion and A/D conversion, on reception data that is wirelessly received via an antenna, and outputs the data to the processor 220. Further, the wireless communication unit 210 performs wireless transmission process, such as D/A conversion and up-conversion, on transmission data generated by the processor 220, and wirelessly transmits the data via the antenna.

[0033] The processor 220 includes, for example, a CPU, an FPGA, a DSP, or the like, and comprehensively controls the entire base station device 200. Specifically, the processor 220 includes a scheduling unit 221, a random access (RA) processing unit 222, and a cancellation control unit 223.

[0034] The scheduling unit 221 performs scheduling of allocating an uplink wireless resource to the terminal device 100 when a scheduling request is transmitted from the terminal device 100. Specifically, the scheduling unit 221 acquires a BSR transmitted from the terminal device 100, and determines a wireless resource for transmitting data accumulated in the transmission buffer of the terminal device 100.

[0035] The RA processing unit 222 performs a random access process of transmitting and receiving various messages when the scheduling request issued by the terminal device 100 is executed through the random access procedure. Specifically, upon receiving a random access preamble, the RA processing unit 222 adds identification information to the random access preamble and causes the wireless communication unit 210 to transmit a random access response including the identification information and an UL grant that indicates a wireless resource for transmitting a next uplink message. Upon receiving the identification information on the terminal device 100, the RA processing unit 222 causes the wireless communication unit 210 to transmit an UL grant indicating the wireless resource that is allocated to the terminal device 100 by the scheduling unit 221.

[0036] The cancellation control unit 223 determines whether to cancel the random access procedure that is executed when scheduling is requested, on the basis of contents of messages transmitted and received in the random access procedure and a status of allocation of a wireless resource to the terminal device 100. Specifically, when a BSR is received using a wireless resource, which has been allocated in advance to the terminal device 100, during execution of the random access procedure, the cancellation control unit 223 causes the RA processing unit 222 to cancel the random access process that is being executed. In other words, when a periodic wireless resource is allocated to the terminal device 100 and the BSR is received using the wireless resource for example, the cancellation control unit 223 cancels the random access process regardless of whether an UL grant is transmitted or not.

[0037] Further, when a BSR is received in response to the UL grant that is included in the random access response during execution of the random access procedure for example, the cancellation control unit 223 determines that the random access procedure is not to be cancelled but to be continued. In other words, when the BSR is received together with the identification information on the terminal device 100 in response to the UL grant that is received during the random access procedure, the cancellation control unit 223 continues the random access procedure to complete transmission of a last UL grant.

[0038] The memory 230 includes, for example, a RAM, a ROM, or the like, and stores therein information used by the processor 220 to perform processes.

[0039] The network IF unit 240 is, for example, an interface that is connected, with wire, to a device constituting a core network.

[0040] Next, a concrete example of the scheduling request in a wireless communication system that includes the terminal device 100 and the base station device 200 configured as described above will be described with reference to FIGS. 3 and 4. FIG. 3 is a sequence diagram illustrating a concrete example of the scheduling request executed through the random access procedure.

[0041] In the wireless communication system illustrated in FIG. 3, before execution of a scheduling request, the base station device 200 allocates a periodic wireless resource to the terminal device 100 in advance, and the terminal device 100 is notified of a wireless resource available to the terminal device 100 for uplink transmission (Step S101). Therefore, even when an explicit UL grant is not received, the terminal device 100 is able to perform uplink transmission using the periodic wireless resource that is allocated in advance. However, the periodic wireless resource allocated in advance is limited, so that when data to be transmitted using uplink is generated, the terminal device 100 requests the base station device 200 to perform uplink scheduling, by issuing a scheduling request using a PUCCH or an RACH. In this example, an explanation will be continued based on the assumption that the scheduling request is executed through the random access procedure using an RACH.

[0042] In the random access procedure, the terminal device 100 transmits the random access preamble to the base station device 200 (Step S102). Upon receiving the random access preamble, the base station device 200 adds identification information to the random access preamble, and transmits a random access response including the identification information and an UL grant indicating a wireless resource that is available for next uplink transmission to the terminal device 100 (Step S103).

[0043] Meanwhile, while the random access procedure is being executed, if a transmission timing of the periodic wireless resource that has been allocated in advance to the terminal device 100 comes, the terminal device 100 may transmit a BSR using the periodic wireless resource in order to promptly start uplink transmission (Step S104). The transmission of the BSR is not based on the UL grant included in the random access response, but may be generated before the terminal device 100 receives the random access response. In other words, the terminal device 100 may promptly transmit the BSR using the wireless resource that has been allocated in advance, regardless of whether the UL grant is received or not.

[0044] When the BSR is transmitted, the cancellation control unit 113 of the terminal device 100 determines whether to cancel the random access procedure (Step S105). Similarly, the cancellation control unit 223 of the base station device 200 determines whether to cancel the random access process performed by the RA processing unit 222 (Step S105). In the determination of the cancellation at this time, it is determined that the random access procedure is to be cancelled when the BSR is transmitted in response to the UL grant, or when the BSR is transmitted using the periodic wireless resource that has been allocated in advance to the terminal device 100. In other words, not only when the BSR is transmitted in response to the UL grant, but also when the BSR is transmitted by the wireless resource that has been allocated in advance regardless of presence or absence of the UL grant, the random access procedure is cancelled.

[0045] After the random access procedure is cancelled, transmission and reception of messages of the random access procedure performed by the UL transmission control unit 112 are stopped in the terminal device 100, and transmission and reception of messages of the random access procedure performed by the RA processing unit 222 are stopped in the base station device 200. With this configuration, it is possible to prevent unnecessary continuation of the random access procedure after the terminal device 100 transmits the BSR and the base station device 200 is enabled to execute scheduling. In other words, it is possible to appropriately cancel the random access procedure.

[0046] FIG. 4 is a sequence diagram illustrating another concrete example of the scheduling request executed by the random access procedure. In FIG. 4, the same components as those illustrated in FIG. 3 are denoted by the same reference signs.

[0047] In the wireless communication system illustrated in FIG. 4, a periodic wireless resource is not allocated to the terminal device 100 in advance, which is different from the example in FIG. 3. Therefore, when data to be transmitted using uplink is generated, the terminal device 100 requests the base station device 200 to perform uplink scheduling by issuing a scheduling request using a PUCCH or an RACH. In this example, an explanation will be given based on the assumption that the scheduling request is executed through the random access procedure using an RACH.

[0048] In the random access procedure, the terminal device 100 transmits a random access preamble to the base station device 200 (Step S102). Upon receiving the random access preamble, the base station device 200 adds identification information to the random access preamble, and transmits a random access response including the identification information and an UL grant indicating a wireless resource available for next uplink transmission to the terminal device 100 (Step S103).

[0049] Upon receiving the random access response, the terminal device 100 transmits the identification information on the terminal device 100 to the base station device 200 in response to the UL grant included in the random access response (Step S201). At this time, the terminal device 100 may transmit a BSR together with the identification information on the terminal device 100 in order to promptly start uplink transmission.

[0050] When the BSR is transmitted, the cancellation control unit 113 of the terminal device 100 determines whether to cancel the random access procedure (Step S105). Similarly, the cancellation control unit 223 of the base station device 200 determines whether to cancel the random access process performed by the RA processing unit 222 (Step S105). In the determination of the cancellation at this time, it is determined that the random access procedure is to be cancelled when the BSR is transmitted in response to the UL grant. However, when the BSR is transmitted in response to the UL grant included in the random access response, it is determined that the random access procedure is not to be cancelled but to be continued. In other words, the random access procedure is cancelled when the BSR is transmitted in response to the UL grant except when the BSR is transmitted in response to the UL grant included in the random access response.

[0051] When the BSR is transmitted in response to the UL grant included in the random access response, the random access procedure is continued; therefore, the base station device 200 transmits an UL grant for permitting the terminal device 100 to perform uplink transmission (Step S202), and the random access procedure is completed. The UL grant transmitted at this time designates a wireless resource available to the terminal device 100 for uplink transmission. Therefore, the terminal device 100 is able to promptly start transmission of data accumulated in the transmission buffer. Further, after the random access procedure is completed, the base station device 200 performs scheduling in accordance with the BSR, and an UL grant is transmitted to the terminal device 100.

[0052] As described above, according to the embodiment, the random access procedure is cancelled when a buffer status report is transmitted in response to an UL grant other than a random access response while a scheduling request is being executed through the random access procedure, and when a buffer status report is transmitted by a periodic wireless resource that has been allocated in advance regardless of presence or absence of the UL grant. Therefore, when the buffer status report used for uplink scheduling is transmitted regardless of presence or absence of the UL grant, it is possible to prevent unnecessary execution of the random access procedure for transmitting the buffer status report. In other words, it is possible to appropriately cancel the random access procedure.

[0053] Furthermore, when a buffer status report is transmitted in response to an UL grant included in the random access response, the random access procedure is not cancelled but continued. Therefore, the UL grant that is transmitted in accordance with the random access procedure is excluded from a condition for cancelling the random access procedure, so that it is possible to prevent the random access procedure from being excessively cancelled.

[0054] Meanwhile, cancellation of the random access procedure may be described as stopping of a pending scheduling request, for example. In addition, cancellation of the random access procedure is performed by, for example, a MAC entity. Specifically, when a MAC PDU is to be transmitted using an UL grant (for example, a second UL grant) other than an UL grant (for example, a first UL grant) provided by (or expected to be provided by) a random access process, the MAC entity is able to stop a random access procedure that the MAC entity has started before configuring a MAC PDU and that is being executed for a pending scheduling request for which a valid PUCCH resource is not set.

[0055] Furthermore, with use of the contents of the embodiment described above, an item of a scheduling request described in, for example, Non Patent Literature 21 (TS38.321) may be updated as illustrated in FIG. 5, for example.

[0056] Moreover, cancellation (stopping) of the random access procedure may be performed in any state in the random access procedure. For example, the random access procedure may be cancelled depending on presence or absence of transmission of a random access response from the base station device 200 to the terminal device 100. Specifically, when the random access response is transmitted, the random access procedure is continued (not cancelled), and when the random access response is not transmitted, the random access procedure is cancelled. Furthermore, the terminal device 100 performs a process by assuming that the random access procedure is cancelled when the random access response is not received (when the random access response is not received for a predetermined time or when a different random access response is received).

Reference Signs List



[0057] 
110, 220
PROCESSOR
111
BSR GENERATING UNIT
112
UL TRANSMISSION CONTROL UNIT
112
TRANSMISSION CONTROL UNIT
113, 223
CANCELLATION CONTROL UNIT
120, 230
MEMORY
130, 210
WIRELESS COMMUNICATION UNIT
221
SCHEDULING UNIT
222
RA PROCESSING UNIT
240
NETWORK IF UNIT



Claims

1. A terminal device comprising:

a generating unit that generates, when requesting transmission of data, a buffer status report indicating an amount of data accumulated in a transmission buffer of the terminal device;

a transmission control unit that executes a random access procedure for transmitting the buffer status report; and

a cancellation control unit that is able to cancel, when the buffer status report is transmitted using a first wireless resource that is allocated in advance to the terminal device, a random access procedure being executed by the transmission control unit, wherein

the cancellation control unit does not cancel the random access procedure when the buffer status report is transmitted using a second wireless resource that is provided by the random access procedure.


 
2. The terminal device according to claim 1, wherein the wireless resource is different from a wireless resource that is allocated in the random access procedure.
 
3. The terminal device according to claim 1 or 2, wherein when the buffer status report is transmitted in response to an uplink (UL) grant that permits uplink transmission, the cancellation control unit cancels the random access procedure being executed by the transmission control unit.
 
4. The terminal device according to claim 3, wherein when the buffer status report is transmitted in response to a UL grant received in the random access procedure, the cancellation control unit continues the random access procedure being executed by the transmission control unit.
 
5. A base station device comprising:

a random access processing unit that executes a random access procedure for receiving a buffer status report that indicates an amount of data accumulated in a transmission buffer of a terminal device in response to a request from the terminal device; and

a cancellation control unit that is able to cancel, when the buffer status report is received using a first wireless resource that is allocated in advance to the terminal device, a random access procedure being executed by the random access processing unit, wherein

the cancellation control unit does not cancel the random access procedure when the buffer status report is received using a second wireless resource that is provided by the random access procedure.


 
6. The base station device according to claim 5, wherein the wireless resource is different from a wireless resource that is allocated in the random access procedure.
 
7. The base station device according to claim 5 or 6, wherein when the buffer status report is received in response to an uplink (UL) grant that permits uplink transmission, the cancellation control unit cancels the random access procedure being executed by the random access processing unit.
 
8. The base station device according to claim 7, wherein when the buffer status report is received in response to a UL grant transmitted in the random access procedure, the cancellation control unit continues the random access procedure being executed by the random access processing unit.
 
9. A wireless communication system comprising:

a terminal device; and

a base station device, wherein

the terminal device includes:

a generating unit that generates, when requesting transmission of data, a buffer status report indicating an amount of data accumulated in a transmission buffer of the terminal device;

a transmission control unit that executes a random access procedure for transmitting the buffer status report; and

a first cancellation control unit that cancels, when the buffer status report is transmitted using a first wireless resource that is allocated in advance to the terminal device, a random access procedure being executed by the transmission control unit, and

the base station device includes:

a random access processing unit that executes a random access procedure for receiving the buffer status report in response to a request from the terminal device; and

a second cancellation control unit that cancels, when the buffer status report is received using the first wireless resource, a random access procedure being executed by the random access processing unit, wherein

the first cancellation control unit and the second cancellation control unit do not cancel the random access procedure when the buffer status report is transmitted and received using a second wireless resource that is provided by the random access procedure.


 
10. A scheduling request method implemented by a terminal device, the scheduling request method comprising:

generating, when requesting transmission of data, a buffer status report indicating an amount of data accumulated in a transmission buffer of the terminal device;

performing a random access procedure for transmitting the buffer status report; and

canceling a random access procedure being executed when the buffer status report is transmitted using a first wireless resource that is allocated in advance to the terminal device, wherein

the canceling includes not cancelling the random access procedure when the buffer status report is transmitted using a second wireless resource that is provided by the random access procedure.


 




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REFERENCES CITED IN THE DESCRIPTION



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Non-patent literature cited in the description