WO2022153445A1

WO2022153445A1 - User terminal and wireless communication method

Info

Publication number: WO2022153445A1
Application number: PCT/JP2021/001069
Authority: WO
Inventors: 陽介秋元
Original assignee: ソフトバンク株式会社
Priority date: 2021-01-14
Filing date: 2021-01-14
Publication date: 2022-07-21

Abstract

The present invention properly controls repetitive transmission of an uplink shared channel which is used in delivery of a message 3 in CBRA. A user terminal according to the present invention comprises: a measurement unit that uses a synchronization signal block to measure reception power or reception quality; a transmission unit that transmits a random access (RA) preamble; a reception unit that receives a response message for the RA preamble; and a control unit that, on the basis of the reception power or the reception quality, decides the number of repetitions of the uplink shared channel which is used in delivery of a message 3 according to the response message.

Description

User terminal and wireless communication method

The present invention relates to a user terminal and a wireless communication method.

In the 3GPP (Third Generation Partnership Project), which is an international standardization organization, LTE (Long Term Evolution), which is the 3.9th generation wireless access technology (RAT), and LTE-Advanced, which is the 4th generation RAT, As a successor, Release 15 of NR (New Radio), which is a 5th generation (Fifth Generation: 5G) RAT, is specified (for example, Non-Patent Document 1). At 3GPP, studies are underway after the release of NR 16.

NR has introduced collision-based random access (CBRA) as a random access procedure. In the CBRA, the user terminal transmits a random access (RandomAccessResponse: RA) preamble (message 1) to the base station via a random access channel (for example, a random access channel (PhysicalRandomAccessChannel: PRACH)).

The user terminal receives a random access response (RAR) message (message 2) for the RA preamble from the base station via a downlink shared channel (for example, Physical Downlink Shared Cannel: PDSCH). The user terminal transmits the message 3 to the base station via the uplink shared channel (for example, Physical Uplink Shared Cannel: PUSCH) in response to the random response message. The user terminal receives the conflict resolution message (contention resolution message) in response to the message 3 via the downlink shared channel.

In Release 17 of NR, it is considered to raise the reachable coverage by identifying the channel that becomes the coverage bottleneck and improving its characteristics. As the channel that becomes the coverage bottleneck, the uplink shared channel used for the transmission of the message 3 in the above CBRA is assumed. Therefore, it has been studied to extend the coverage by repeatedly transmitting the uplink shared channel used for the transmission of the message 3.

The present invention has been made in view of such circumstances, and an object of the present invention is to provide a user terminal and a wireless communication method capable of appropriately controlling repeated transmission of an uplink shared channel used for transmission of message 3 in CBRA. Make one.

A user terminal according to one aspect of the present invention includes a measuring unit that measures received power or reception quality using a synchronous signal block, a transmitting unit that transmits a random access (RA) preamble, and a response message to the RA preamble. A receiving unit that receives the message 3 and a control unit that determines the number of repetitions of the uplink shared channel used for transmitting the message 3 in response to the response message based on the received power or the reception quality.

According to the present invention, it is possible to appropriately control the repeated transmission of the uplink shared channel used for the transmission of the message 3 in the CBRA.

It is a figure which shows an example of the outline of the wireless communication system which concerns on this embodiment. It is a figure which shows an example of RO which concerns on this embodiment. It is a figure which shows an example of the hardware composition of each apparatus in the wireless communication system which concerns on 1st Embodiment. It is a figure which shows an example of the functional block composition of the user terminal which concerns on 1st Embodiment. It is a figure which shows an example of the determination criterion of the repetition number R which concerns on 1st Embodiment. It is a figure which shows another example of the determination criterion of the repetition number R which concerns on 1st Embodiment. It is a figure which shows an example of the functional block composition of the base station which concerns on 1st Embodiment. It is a figure which shows an example of the operation of CBRA which concerns on 1st Embodiment. It is a figure which shows an example of the determination criterion of the repetition number R which concerns on 2nd Embodiment. It is a figure which shows another example of the determination criterion of the repetition number R which concerns on 2nd Embodiment. It is a figure which shows an example of the operation of CBRA which concerns on 2nd Embodiment.

An embodiment of the present invention will be described with reference to the accompanying drawings. In each figure, those having the same reference numerals may have the same or similar configurations.

FIG. 1 is a diagram showing an example of an outline of a wireless communication system according to the present embodiment. As shown in FIG. 1, the wireless communication system 1 may include a user terminal 10, base stations 20A to 20B, and a core network 30. When the base stations 20A to 20B and the cells C1 to C2 are not distinguished, they are collectively referred to as the base station 20 and the cell C, respectively. Further, the numbers of the user terminals 10 and the base stations 20 shown in FIG. 1 are merely examples, and are not limited to the numbers shown.

The wireless communication system 1 operates with one or more wireless access technologies (RAT). For example, the wireless communication system 1 may operate in either LTE, LTE-Advanced or NR, or may operate in a plurality of RATs (multi-RAT) including LTE and / or LTE-Advanced and NR. May be good. LTE and / or LTE-Advanced is also referred to as Evolved Universal Terrestrial Radio Access (EUTRA).

As shown in FIG. 1, the user terminal 10 is a predetermined terminal or device such as a smartphone, a personal computer, an in-vehicle terminal, an in-vehicle device, a stationary device, or the like. The user terminal 10 may be called a User Equipment (UE) or the like. The user terminal 10 may be a mobile type or a fixed type. The user terminal 10 is configured to be communicable with, for example, at least one RAT of EUTRA and NR.

Base station 20 forms one or more cells C. The cell C may be paraphrased as a serving cell, a carrier, a component carrier (CC), a primary cell (Primary Cell: PCell), a secondary cell (Secondary Cell: SCell), a special cell (Special Cell), or the like. In FIG. 1, the

base stations

20A and 20B form cells C1 and C2, respectively, but the present invention is not limited to this, and each base station may form one or more cells C. Further, the plurality of base stations 20 may be connected to each other by a predetermined interface (for example, X2 or Xn interface).

The base station 20 communicates with the user terminal 10 by either EUTRA or NR communication method. The base station 20 includes eNodeB (eNB), ng-eNB, gNodeB (gNB), en-gNB, Next Generation-Radio Access Network (NG-RAN) node, Donor eNodeB (DeNB), Donor eNodeB (DeNB), Donor node. , CentralUnit, low-power node, picoeNB, HomeeNB (HeNB), DistributedUnit (DU), gNB-DU, RemoteRadioHead (RRH), or Integrated Access and Backhaul / Backhauling It may be called a (IAB) node or the like.

The core network 30 is, for example, a core network compatible with EUTRA (Evolved Packet Core: EPC) or a core network compatible with NR (5G Core Network: 5GC). The device on the core network 30 (hereinafter, also referred to as “core network device”) manages mobility such as paging and location registration of the user terminal 10. The core network device may be connected to the base station 20 via a predetermined interface (for example, S1 or NG interface).

The core network device includes, for example, a Mobility Management Entity (MME) that manages the movement of the user terminal 10, an Access and Mobility Management Function (AMF) that manages C-plane information (for example, information related to access and movement management, etc.), and U. It may include at least one User Plane Function (UPF) that controls the transmission of plane information (for example, user data).

In the wireless communication system 1, the user terminal 10 can communicate with one or more base stations 20. For example, in FIG. 1, the user terminal 10 can perform communication by dual connectivity (DC) connected to two cell groups including one or more cells C, respectively. When two cell groups use different RATs, the DC may be referred to as a multi-RAT DC. Further, the user terminal 10 can also perform communication by using carrier aggregation (CA) that integrates a plurality of cells C.

(Channel / signal)
Next, the channel and / or signal (hereinafter, also referred to as “channel / signal”) used in the wireless communication system 1 will be described. The downlink channel / signal transmitted from the base station 20 to the user terminal 10 includes, for example, at least one of the following.
-A broadcast channel used for transmitting broadcast information (for example, a physical broadcast channel (PBCH)).
-Synchronization signal (for example, Primary Synchronization Signal (PSS) and / or Secondary Synchronization Signal (PSS))
-Downlink shared channel used for downlink data transmission (for example, Physical Downlink Shared Channel (PDSCH))
-Downlink control channel (for example, Physical Downlink Control Channel (PDCCH)) used for transmission of downlink control information (DCI).
-Downlink reference signal (for example, demodulation reference signal (DMRS) of PDCCH, PDSCH or PBCH, channel state information reference signal (CSI-RS), etc.).

Further, the uplink channel / signal transmitted from the user terminal 10 to the base station 20 includes at least one of the following.
Random Access Channel (eg, Physical Random Access Channel (PRACH)) used to transmit random access (RA) preambles.
-Uplink control channel (for example, Physical Uplink Control Channel (PUCCH)) used for transmission of uplink control information (UCI).
-Uplink shared channel used for uplink data transmission (for example, Physical Uplink Shared Channel (PUSCH))
-Uplink reference signal (for example, PUCCH and / or PUSCH DMRS, Sounding Reference Signal (SRS), etc.)

In the following, the broadcast channel, the downlink shared channel, and the downlink control channel included in the downlink channel / signal will be referred to as PBCH, PDSCH, and PDCCH, respectively, but the names are not limited to these, respectively. Further, the random access channel, the uplink control channel, and the uplink shared channel included in the uplink channel / signal are referred to as PRACH, PUCCH, and PUSCH, respectively, but the names are not limited to these, respectively.

The notification information transmitted by PBCH includes system information. Further, the downlink data transmitted by the PDSCH includes, for example, system information, downlink user data, RRC (Radio Resource Control) layer information (for example, RRC message, RRC Information Element: RRC IE), and the like. At least one of MAC (Medium Access Control) layer information (for example, MAC Control Element (MAC CE)) may be included.

System information is transmitted via PBCH and / or PDSCH as described above. Further, the system information includes a master information block (MasterInformation Block: MIB) and one or more system information blocks (SystemInformation Block: SIB) (for example, SIB1 to SIB9, etc.). The user terminal 10 receives the MIB via the PBCH. The user terminal 10 may detect the DCI based on the information in the MIB and receive the SIB1 via the PDSCH based on the DCI. The user terminal 10 may detect the DCI based on the information contained in the SIB1 and receive other system information (for example, at least one of the SIBs 2 to 9) via the PDSCH based on the DCI.

The DCI transmitted by the PDCCH is used for scheduling the PDSCH and / or PUSCH, and is also called a DCI format, scheduling information, or the like. The user terminal 10 monitors the PDCCH candidate (PDCCH candidate) in the search space, detects the DCI, and receives the downlink data via the PDSCH or the uplink data via the PUSCH based on the detected DCI. To send.

(CBRA)
Next, collision-based random access (CBRA) in the wireless communication system 1 will be described.

In cell C, a synchronization signal block (SSB) containing at least one of PBCH, DMRS, SSS, and PSS of PBCH and PBCH is transmitted from the base station 20 at a predetermined cycle. SSB may be paraphrased as SS / PBCH block. For example, each SSB may consist of 4 symbols and 20 resource blocks.

An identifier (hereinafter referred to as "SSB index") is attached to each SSB. The base station 20 may transmit the plurality of SSBs by applying different beam patterns to the plurality of SSBs having different SSB indexes. Specifically, the base station 20 may transmit the plurality of SSBs at predetermined cycles using different time resources (for example, different symbols) by beam sweeping (“multi-beam operation”). Also called). Alternatively, the base station 20 may transmit one SSB in a single beam pattern at a predetermined cycle without applying beam sweeping (also referred to as “single beam operation”). The user terminal 10 may detect the timing of the radio frame and / or slot based on the SSB index.

In CBRA, first, the user terminal 10 may transmit the RA preamble. Specifically, the user terminal 10 may transmit the RA preamble using the RACH opportunity (RACHoccasion: RO) associated with the detected SSB. By transmitting the RA preamble using the RO associated with the SSB during multi-beam operation, the base station 20 can recognize the received beamforming applied to the reception of the RA preamble.

Here, the RO is a resource in the time domain and / or frequency domain for transmission of the RA preamble, and is composed of, for example, one or more symbols and M (M ≧ 1) resource blocks (Resource Block: RB). You may. RO may be paraphrased as PRACH opportunity, random access opportunity, transmission opportunity, opportunity and the like. Further, the RA preamble may be paraphrased as a RACH preamble, PRACH, message 1, and the like.

FIG. 2 is a diagram showing an example of RO according to this embodiment. As shown in FIG. 2, one or a plurality of slots (hereinafter, referred to as “RACH slots”) used for transmitting the RA preamble are provided in a predetermined cycle (hereinafter, referred to as “RACH resource periodicity”). You may. For example, in FIG. 2, the RACH resource cycle is 10 slots, and the 2nd, 5th, and 8th slots are RACH slots, but the present invention is not limited to this.

As shown in FIG. 2, each RACH slot is provided with one or more ROs. One RO is composed of M (M ≧ 1) RBs. K ROs can be arranged in the frequency domain. Further, one or more ROs can be arranged in one RACH slot in the time domain. For example, in FIG. 2, a total of 4ROs, two in the frequency domain and two in the time domain, are arranged per RACH slot. Note that FIG. 2 is merely an example, and the number of ROs in the frequency domain may be 1 or more, and the number of ROs in the time domain in the 1 RACH slot may be 1 or more. As such, each RACH slot may include one or more ROs in the time domain and / or frequency domain. It should be noted that the plurality of RACH slots do not have to be continuous in the time domain.

Further, as shown in FIG. 2, one SSB may be associated with one or more ROs. For example, in FIG. 2, SSB # 0 is associated with RO # 0 to # 3, and SSB # 1 is associated with RO # 4 to # 7. Further, each SSB may be associated with a predetermined number of RA preambles. The number of SSBs N associated with one RO is not limited to 1/4 shown in FIG. The SSB number N may be, for example, a value less than or equal to 1 such as 1/2 or 1/8, or a value greater than 1 such as 2, 4, 8, 17 or the like. .. The number of SSBs may be configured from the base station 20 to the user terminal 10 by, for example, the information item "ssb-perRACHOccasionAndCB-PreamblesPerSSB" of the radio resource control (RadioResourceControl: RRC). As shown in FIG. 2, when N <1, one SSB is associated with a plurality of ROs. On the other hand, although not shown, when N> 1, a plurality of SSBs are associated with one RO. When N = 1, one SSB is associated with one RO.

For example, in FIG. 2, when detecting SSB # 0, the user terminal 10 selects any of RO # 0 to # 3 associated with SSB # 0. Further, the user terminal 10 selects one of the RA preambles associated with SSB # 0, and transmits the selected RA preamble using the selected RO.

In CBRA, secondly, the user terminal 10 receives the RAR message (message 2) for the RA preamble from the base station 20 via the PDSCH. Third, the user terminal 10 transmits the message 3 to the base station 20 via the PUSCH scheduled by the uplink included in the random response message. Fourth, the user terminal 10 receives the conflict resolution message (message 4) corresponding to the message 3 via the PDSCH.

Note that the message 3 may be paraphrased as an RRC setup request (RRCSetupRequest) message or the like. Hereinafter, the PUSCH used for transmitting the message 3 is referred to as "Msg.3 PUSCH", but may be simply referred to as "message 3" or the like. Further, the message 4 may be paraphrased as an RRC setup message, a conflict resolution message, or the like.

In Release 17 of NR, it is considered to raise the reachable coverage by identifying the channel that becomes the coverage bottleneck and improving its characteristics. The channel that becomes the coverage bottleneck is described in Msg. 3 PUSCH is assumed. Therefore, the Msg. 3 It is being considered to extend the coverage by supporting the repeated transmission of PUSCH.

However, Msg. 3 Whether or not PUSCH becomes a coverage bottleneck depends on the position of the user terminal 10 and the like. Although the user terminal 10 is not located at the coverage boundary, the user terminal 10 has the Msg. 3 Only having the ability to repeatedly transmit PUSCH, the Msg. 3 Repeated transmission of PUSCH may lead to a decrease in utilization efficiency of wireless resources.

Therefore, in the present embodiment, the user terminal 10 uses Msg. 3 Control the repeated transmission of PUSCH. As a result, the number of repetitions R (R ≧ 1, where R = 1 is the first transmission) can be determined based on the position of the user terminal 10 estimated from the received power or the reception quality, so that the utilization efficiency of wireless resources is improved. can.

Further, in the present embodiment, the RA preamble or RO is determined based on the received power or the received quality. Therefore, the RA preamble or RO determines the RA preamble or RO. 3 The PUSCH repetition number R can be implicitly notified from the user terminal 10 to the base station 20. Therefore, while eliminating redundant signaling between the user terminal 10 and the base station 20, the above Msg. 3 It is possible to appropriately control the repeated transmission of PUSCH.

In the following, the received power is assumed to be a reference signal received power (RSRP) measured using a synchronization signal or a downlink reference signal (for example, DMRS of PBCH, CSI-RS, etc.). Similarly, the reception quality is assumed to be a reference signal reception quality (RSRQ) measured using a synchronization signal or a downlink reference signal (for example, DMRS or CSI-RS of PBCH). The present embodiment is not limited to RSRP or RSRQ, and can be applied to any index relating to the signal reception level of the user terminal 10.

[First Embodiment]
(Configuration of wireless communication system)
Next, the configuration of each device of the wireless communication system 1 according to the first embodiment will be described. It should be noted that the following configurations are for showing the configurations required in the description of the first embodiment, and do not exclude that each device includes a functional block other than those shown in the drawings.

<Hardware configuration>
FIG. 3 is a diagram showing an example of the hardware configuration of each device in the wireless communication system according to the first embodiment. Each device in the wireless communication system 1 (for example, each of the user terminal 10 and the base station 20) includes a processor 11, a memory 12, a storage device 13, a communication device 14 that performs wired or wireless communication, and an input device 15 that accepts input operations. It has at least an output device 16 that outputs information and one or more antennas 17.

The processor 11 is, for example, a CPU (Central Processing Unit) and controls each device in the wireless communication system 1. The processor 11 may constitute a control unit that controls each device.

The memory 12 is composed of, for example, a ROM (ReadOnlyMemory), an EPROM (ErasableProgrammableROM), an EEPROM (ElectricallyErasableProgrammableROM), and / or a RAM (RandomAccessMemory).

The storage device 13 is composed of storage such as HDD (Hard Disk Drive), SSD (Solid State Drive) and / or eMMC (embedded MultiMediaCard), for example.

The communication device 14 is a device that communicates via a wired and / or wireless network, and is, for example, a network card, a communication module, or the like. Further, the communication device 14 may include an RF (Radio Frequency) device that performs processing related to an amplifier and a radio signal, and a BB (BaseBand) device that performs baseband signal processing.

The RF device generates a radio signal transmitted from the antenna 17 by performing D / A conversion, modulation, frequency conversion, power amplification, etc. on the digital baseband signal received from the BB device, for example. Further, the RF device generates a digital baseband signal by performing frequency conversion, demodulation, A / D conversion, etc. on the radio signal received from the antenna 17, and transmits the digital baseband signal to the BB device. The BB apparatus performs a process of converting a digital baseband signal into an IP packet and a process of converting an IP packet into a digital baseband signal.

The input device 15 is, for example, a keyboard, a touch panel, a mouse and / or a microphone. The output device 16 is, for example, a display and / or a speaker.

<Functional block configuration>
≪User terminal≫
FIG. 4 is a diagram showing an example of the functional block configuration of the user terminal according to the first embodiment. As shown in FIG. 4, the user terminal 10 includes a receiving unit 101, a transmitting unit 102, a control unit 103, and a measuring unit 104.

The receiving unit 101 receives the downlink channel / signal. In addition, the receiving unit 101 performs processing (for example, demapping, demodulation, decoding, etc.) on information and / or data transmitted via the downlink channel / signal.

Specifically, the receiving unit 101 may receive a synchronization signal or a downlink reference signal (for example, DMRS or CSI-RS of PBCH) used for measuring RSRP or RSRQ by the measuring unit 104.

Further, the receiving unit 101 may receive the system information broadcast from the base station 20. The system information includes MIB and / or SIBX (where X is an arbitrary integer). For example, the receiving unit 101 may receive the MIB via the PBCH. Further, the receiving unit 101 may receive SIBX via PDSCH. In addition, the receiving unit 101 receives the RAR message (message 2) via the PDSCH. Further, the receiving unit 101 receives the conflict resolution message (message 4) via the PDSCH.

Further, the receiving unit 101 may receive information regarding the association between the RSRP or RSRQ measured by the measuring unit 104 and the repetition number R (hereinafter, referred to as “first association information”). The first association information includes, for example, a set of one or more thresholds of RSRP or RSRQ (for example, thresholds α and β described in FIGS. 5 and 6), a condition determined based on the threshold, and Msg associated with the condition. .. 3 Information indicating at least one such as the number of repetitions R of PUSCH may be used.

Further, the receiving unit 101 provides information regarding the association between the RSRP or RSRQ (and / or the number of repetitions R) measured by the measuring unit 104 and the RA preamble or RO (hereinafter, referred to as “second association information”). You may receive it. The second association information includes, for example, a set of one or more thresholds of RSRP or RSRQ (eg, thresholds α and β described in FIGS. 5 and 6), conditions determined based on the thresholds, and RO associated with the conditions. Alternatively, it may be information indicating at least one such as RA preamble and the number of repetitions R associated with the condition.

Note that the first and second association information may be included in the system information (for example, SIBX). Further, the first and second association information does not have to be received separately, and may be received as association information regarding the association between the RSRP or RSRQ, the repetition number R, and the RA preamble or RO.

The transmission unit 102 transmits an upstream channel / signal. In addition, the transmission unit 102 performs processing (for example, coding, modulation, mapping to resources, etc.) regarding information and / or data transmitted via the upstream channel / signal.

Further, the transmission unit 102 transmits the RA preamble (message 1). Specifically, the transmission unit 102 may transmit the RA preamble selected by the control unit 103 based on RSRP or RSRQ. Further, the transmission unit 102 may transmit the RA preamble using the RO selected by the control unit 103 based on RSRP or RSRQ.

The transmission unit 102 is a Msg. 3 Send PUSCH. Specifically, the transmission unit 102 has the Msg. 3 PUSCH may be repeatedly transmitted. Note that R = 1 may indicate the first transmission, and R = 2, 3, ... May indicate the second, third, ... Transmission.

The control unit 103 controls the transmission of the downlink channel / signal by the reception unit 101 and / or the reception of the uplink channel / signal by the transmission unit 102.

Specifically, the control unit 103 is based on the RSRP or RSRQ measured by the measurement unit 104, and Msg. 3 Control the repeated transmission of PUSCH. Specifically, the control unit 103 uses Msg. 3 The number of repetitions R of PUSCH may be determined. For example, the control unit 103 may determine the number of repetitions R associated with the RSRP or RSRQ measured by the measurement unit 104 based on the criteria illustrated in FIGS. 5 and 6.

FIG. 5 is a diagram showing an example of a criterion for determining the number of repetitions R according to the first embodiment. For example, in the determination criterion shown in FIG. 5, the condition relating to the measured value of RSRP (hereinafter referred to as “RSRP measured value”), RO, and the number of repetitions R are associated with each other.

The threshold values α and β that determine the conditions in FIG. 5 and / or the association between the conditions and the number of repetitions R may be indicated by the above-mentioned first association information, or may be predetermined in the specifications. .. Further, the threshold values α and β and / or the association between the condition and RO may be indicated by the above-mentioned second association information, or may be predetermined in the specifications.

For example, in FIG. 5, when the RSRP measurement value is equal to or higher than the threshold value α, RO # 4k (k = 0, 1, 2, ...) (For example, RO # 0, # 4, # in FIG. 2) is used to transmit the RA preamble. 8, ...), Msg. 3 It is shown that the repetition number R of PUSCH is set to 1 time. Further, when the RSRP measured value is smaller than the threshold value α and equal to or higher than the threshold value β, RO # 4k + 1 (k = 0, 1, 2, ...) (For example, RO # 1, # 5, # in FIG. 2) is used to transmit the RA preamble. 9, ...), Msg. 3 It is shown that the repetition number R of PUSCH is set to 2 times. If the RSRP measurement value is smaller than the threshold value β, RO # 4k + 2 (k = 0, 1, 2, ...) (For example, RO # 2, # 6, # 10, ... In FIG. 2) is used to transmit the RA preamble. Use, Msg. 3 It is shown that the number of repetitions R of PUSCH is set to 4 times.

According to the criterion shown in FIG. 5, if the RSRP measurement value is smaller than the threshold value α and equal to or higher than the threshold value β, the user terminal 10 that has detected SSB # 0 transmits the RA preamble using RO # 1 in FIG. , Msg. 3 Repeat PUSCH twice and send. On the other hand, even in the user terminal 10 that detects the same SSB # 0, if the RSRP measurement value is smaller than the threshold value β, the RA preamble is transmitted using RO # 2 in FIG. 3 Repeat PUSCH 4 times to transmit.

In this way, when a plurality of ROs (4ROs in FIG. 2) are associated with each SSB, the RSRP measurement values (and / or the number of repetitions R) under different conditions are associated with the plurality of ROs to perform multi. During beam operation, the number of repetitions R of the user terminal 10 at different positions in the same beam direction (for example, a position close to the base station 20 or a coverage boundary) can be appropriately controlled. Further, when the user terminal 10 uses the RO associated with the RSRP measurement value (and / or the number of repetitions R), the base station 20 can use the Msg. 3 The number of repetitions R of PUSCH can be recognized in advance.

FIG. 6 is a diagram showing another example of the criterion for determining the number of repetitions R according to the first embodiment. The criterion shown in FIG. 6 differs from the criterion shown in FIG. 5 in that instead of RO, the RA preamble is associated with the condition for the RSRP measurement and the number of repetitions R. In the following, the differences from the judgment criteria shown in FIG. 5 will be mainly described. In FIG. 6, the association between the threshold values α and β and / or the condition based on the α and β and the RA preamble may be indicated by the above-mentioned second association information, or may be determined in advance in the specifications. May be done.

For example, in FIG. 6, when the RSRP measurement value is equal to or higher than the threshold value α, use any of i RA preambles a ₀ to a _i-1 , and Msg. 3 It is shown that the number of repetitions R of PUSCH is one. When the RSRP measurement value is smaller than the threshold value α and equal to or higher than the threshold value β, use any of j RA preambles b ₀ to b _j-1 , Msg. 3 It is shown that the repetition number R of PUSCH is set to 2 times. When the RSRP measurement value is smaller than the threshold value β, use any of k RA preambles c ₀ to c _k-1 , and use Msg. 3 It is shown that the number of repetitions R of PUSCH is set to 4 times.

According to the determination criteria shown in FIG. 6, if the RSRP measurement value is smaller than the threshold value α and equal to or higher than the threshold value β, the user terminal 10 transmits one of RA preambles b ₀ to b _j-1 , and Msg. 3 PUSCH is repeated twice and transmitted. On the other hand, even in the user terminal 10 that detects the same SSB # 0, if the RSRP measurement value is smaller than the threshold value β, any one of RA preambles c ₀ to c _k-1 is transmitted, and Msg. 3 PUSCH is repeated 4 times and transmitted.

In this way, by using the repetition number R associated with the condition regarding the RSRP measurement value, the user terminal 10 can use the repetition number R according to its own position to obtain Msg. 3 PUSCH can be sent. Further, the user terminal 10 uses the RA preamble associated with the RSRP measurement value (and / or the number of repetitions R), so that the base station 20 can use the Msg. 3 The number of repetitions R of PUSCH can be recognized in advance.

The judgment criteria shown in FIGS. 5 and 6 are merely examples, and are not limited to those shown. For example, in FIGS. 5 and 6, two threshold values α and β are shown, but the number of threshold values may be 1 or more. Of course, the RO or RA preamble associated with each condition is not limited to the one shown in the figure. Further, although the judgment criteria based on the RSRP measured values are shown in FIGS. 5 and 6, it goes without saying that they may be replaced with the measured values of RSRQ. Of course, the above criteria can also be applied during multi-beam operation and / or single-beam operation.

The measuring unit 104 measures the RSRP or RSRQ of the synchronization signal or the downlink reference signal (for example, DMRS or CSI-RS of PBCH). For example, the measuring unit 104 may measure RSRP or RSRQ using SSB.

The receiving unit 101, the transmitting unit 102, and the measuring unit 104 may be realized by, for example, the communication device 14, or may be realized by the processor 11 executing the program stored in the storage device 13 in addition to the communication device 14. May be done. The control unit 103 may be realized by the processor 11 executing the program stored in the storage device 13. When executing a program, the program may be stored in a storage medium. The storage medium in which the program is stored may be a computer-readable non-transitory storage medium (Non-transitory computer readable medium). The non-temporary storage medium is not particularly limited, but may be, for example, a storage medium such as a USB (Universal Serial Bus) memory or a CD-ROM (Compact Disc ROM).

≪Base station≫
FIG. 7 is a diagram showing an example of the functional block configuration of the base station according to the first embodiment. As shown in FIG. 7, the base station 20 includes a transmission unit 201, a reception unit 202, and a control unit 203.

The transmission unit 201 transmits a downlink channel / signal. In addition, the transmission unit 201 performs processing (for example, encoding, decoding, mapping to resources, etc.) regarding information and / or data transmitted via the downlink channel / signal.

Specifically, the transmission unit 201 may transmit a synchronization signal or a downlink reference signal (for example, DMRS or CSI-RS of PBCH) used for measuring RSRP or RSRQ. Further, the transmission unit 201 may notify the system information. For example, the transmission unit 201 may transmit the MIB via the PBCH. Further, the transmission unit 201 may transmit SIBX via PDSCH.

Further, the transmission unit 201 transmits a RAR message (message 2) via the PDSCH. Further, the transmission unit 201 transmits a conflict resolution message (message 4) via the PDSCH.

Further, the transmission unit 201 may transmit the above-mentioned first association information. Further, the transmission unit 201 may transmit the second association information. The first and second association information may be included in the system information (for example, SIBX). The first and second association information does not have to be transmitted separately, and may be transmitted as association information relating to the association between the RSRP or RSRQ, the repetition number R, and the RA preamble or RO.

The receiving unit 202 receives the upstream channel / signal. In addition, the receiving unit 202 performs processing (for example, demapping, demodulation, decoding, etc.) on information and / or data transmitted via the upstream channel / signal.

Further, the receiving unit 202 receives the RA preamble (message 1). Specifically, the receiving unit 202 may receive the RA preamble associated with the RSRP or RSRQ measured by the measuring unit 104. Alternatively, the receiving unit 202 may receive the RA preamble using the RO associated with the RSRP or RSRQ.

The receiving unit 202 is a Msg. 3 Receive PUSCH. The receiving unit 202 has the Msg. 3 Assuming that PUSCH is repeated, the Msg. 3 PUSCH may be received.

The control unit 203 controls the transmission of the downlink channel / signal by the transmission unit 201 and / or the reception of the uplink channel / signal by the reception unit 202. Further, the control unit 203 may control the scheduling of PDSCH and / or PUSCH.

The control unit 203 uses the RA preamble received by the reception unit 202 or the RO used for transmitting the RA preamble to obtain Msg. 3 The number of repetitions R of PUSCH may be determined. Specifically, the control unit 203 may determine the number of repetitions R associated with the RA preamble or RO, for example, according to the determination criteria shown in FIGS. 5 and 6.

The transmitting unit 201 and the receiving unit 202 may be realized by, for example, the communication device 14, or may be realized by the processor 11 executing the program stored in the storage device 13 in addition to the communication device 14. .. The control unit 203 may be realized by the processor 11 executing the program stored in the storage device 13.

(Operation of wireless communication system)
Next, the operation of the wireless communication system 1 according to the first embodiment will be described. FIG. 8 is a diagram showing an example of the operation of the CBRA according to the first embodiment. The operation shown in FIG. 8 is merely an example, and the order of at least some steps may be changed, omitted, and / or added.

As shown in FIG. 8, in step S101, the user terminal 10 detects the SSB from the base station 20. In step S102, the user terminal 10 measures RSRP or RSRQ using SSB.

In step S103, the user terminal 10 receives the SIB via the PDSCH. The SIB may be a plurality of SIBXs having different values of X, or may be received via a plurality of PDSCHs. In addition, the SIB may include first and second association information used for deriving the determination criteria (for example, FIGS. 5 and 6) based on the RSRP or RSRQ.

In step S104, the user terminal 10 selects RA preamble or RO based on the RSRP measurement value or RSRQ measurement value in step S102 (see, for example, FIGS. 5 and 6).

In step S105, the user terminal 10 uses a certain RO to transmit the RA preamble (message 1) selected in step S104. Alternatively, the user terminal 10 transmits a certain RA preamble (message 1) using the RO selected in step S104.

In step S106, the base station 20 receives the RA preamble received in step S105 or the Msg. 3 Determine the number of repetitions R of PUSCH. In step S107, the base station 20 transmits a RAR message (message 2) for the RA preamble received in step S105. In addition, the content and the number of bits of the upstream grant included in the RAR message are described in Msg. 3 The same number of bits (for example, 27 bits) may be used regardless of the number of repetitions R of PUSCH.

In step S108, the user terminal 10 uses the Msg. 3 Determine the number of repetitions R of PUSCH (see, for example, FIGS. 5 and 6). In addition, the user terminal 10 is based on the RO or RA preamble selected in step S104, and Msg. 3 The number of repetitions R of PUSCH may be determined (see, for example, FIGS. 5 and 6).

In step S109, the user terminal 10 has Msg. 3 Repeat PUSCH to send. The base station 20 has the Msg. 3 Performs PUSCH reception processing. For example, the base station 20 has Msg. 3 PUSCH may be synthesized. In step S110, the user terminal 10 receives the conflict resolution message (message 4).

According to the wireless communication system 1 according to the first embodiment, since the repetition number R is associated with the RSRP measurement value or the RSRQ measurement value, Msg. 3 PUSCH can be repeatedly transmitted, and the utilization efficiency of wireless resources can be improved. Further, since the RSRP measurement value or the RSRQ measurement value (and / or the repetition number R) is associated with the RO or RA preamble, the base station 20 can perform Msg. 3 The number of repetitions R of PUSCH can be recognized.

[Second Embodiment]
Next, the configuration of each device of the wireless communication system 1 according to the second embodiment will be described. In the second embodiment, the user terminal 10 controls the repeated transmission of the message 3 based on the power class of the user terminal 10 in addition to the RSRP measurement value or the RSRQ measurement value. Different from. In the second embodiment, the differences from the first embodiment will be mainly described.

(Configuration of wireless communication system)
The user terminal 10 and the base station 20 according to the second embodiment have the hardware configuration shown in FIG. Further, the user terminal 10 and the base station 20 have the configurations shown in FIGS. 4 and 7 and have the following functions.

In the second embodiment, the receiving unit 101 of the user terminal 10 may receive the first association information for each power class (Power Class: PC), or the first association of a specific PC. Information may be received. Further, the receiving unit 101 may receive the second association information for each PC, or may receive the second association information of a specific PC.

Here, the PC is a class related to the maximum transmission power of the user terminal 10, and is also called an output class. For example, the maximum transmission power of PC3 is 23 dBm, whereas the maximum transmission power of PC2 is 26 dBm.

The first and second association information for each PC or the first and second association information for a specific PC may be included in the system information (for example, SIBX). Further, the first and second association information does not have to be received separately, and may be received for each PC or for a specific PC as the association information regarding the association between RSRP or RSRQ and the repetition number R and RA preamble or RO. good.

The control unit 103 is based on the RSRP or RSRQ measured by the measurement unit 104 and the PC of the user terminal 10, and Msg. 3 Control the repeated transmission of PUSCH. Specifically, the control unit 103 is based on the RSRP or RSRQ and the PC of the user terminal 10, and Msg. 3 Determine the number of repetitions R of PUSCH. For example, the control unit 103 may determine the number of repetitions R associated with the RSRP or RSRQ measured by the measurement unit 104 based on the criteria illustrated in FIGS. 9 and 10.

FIG. 9 is a diagram showing an example of a criterion for determining the number of repetitions R according to the second embodiment. For example, in the determination criteria shown in FIG. 9, the condition regarding the RSRP measured value, RO, and the number of repetitions R are associated with each PC. The association between the condition regarding the RSRP measurement value of each PC shown in FIG. 9 and the repetition number R may be indicated by the first association information for each PC received by the receiving unit 101, or the first association of the specific PC. It may be derived from the association information of. Similarly, the association between the RO and the condition regarding the RSRP measurement value of each PC shown in FIG. 9 may be indicated by the second association information for each PC received by the receiving unit 101, or the second association information of the specific PC. It may be derived from the association information of 2.

For example, when the first association information of each PC is received, the control unit 103 determines the condition regarding the RSRP measurement value of each PC, the number of repetitions R, and RO based on the first and second association information of each PC. You may derive the association with. Specifically, "-110" is notified from the base station 20 as the threshold value α _PC3 of the PC3 having the maximum transmission power of 23 dBm, and “-113” is notified from the base station 20 as the threshold value α _PC2 of the PC2 having the maximum transmission power of 26 dBm. You may be notified.

Alternatively, when the receiving unit 101 receives the first and second association information of a specific PC (for example, PC3), the control unit 103 determines the other PC based on the first and second association information. The condition regarding the RSRP measurement value of (for example, PC2) and the association between the number of repetitions R and RO may be derived. Specifically, when "-110" is notified from the base station 20 as the threshold value α _PC3 of the PC3 having the maximum transmission power of 23 dBm, the control unit 103 transmits the maximum transmission based on the threshold value α _PC3 and the predetermined offset Y. The threshold value α _PC2 of PC2 having a power of 26 dBm may be derived. The offset Y may be, for example, the difference in the maximum transmission power between the PCs (here, the maximum transmission power of the PC3 is 23 dBm-the maximum transmission power of the PC2 is 26 dBm = -3 dBm), or a value determined in advance in the specifications. It may be. The same applies to β _PC3 and β _PC2 .

For example, in FIG. 9, when the PC of the user terminal 10 is PC2, and the RSRP measurement value is the threshold value α _PC2 or more, RO # 4k (k = 0, 1, 2, ...) (For example, , RO # 0, # 4, # 8, ...) In FIG. 2, Msg. 3 It is shown that the number of repetitions R of PUSCH is one. Further, when the RSRP measured value is smaller than the threshold value α _PC2 and equal to or higher than the threshold value β _PC2 , RO # 4k + 1 (k = 0, 1, 2, ...) (For example, RO # 1, # 5 in FIG. 2) is used to transmit the RA preamble. , # 9, ...), Msg. 3 It is shown that the repetition number R of PUSCH is set to 2 times. When the RSRP measurement value is smaller than the threshold value β _PC2 , RO # 4k + 2 (k = 0, 1, 2, ...) (For example, RO # 2, # 6, # 10, ... In FIG. 2) is used to transmit the RA preamble. , Msg. 3 It is shown that the number of repetitions R of PUSCH is set to 4 times.

FIG. 10 is a diagram showing another example of the criterion for determining the number of repetitions R according to the second embodiment. The criteria shown in FIG. 10 differ in that instead of RO, the RA preamble is associated with the condition for the RSRP measurement and the number of repetitions R, but the other points are the same. The control unit 103 may derive the association between the condition regarding the RSRP measurement value of each PC and the repetition number R and the RA preamble based on the first and second association information of each PC. Alternatively, the control unit 103 may derive the association between the condition regarding the RSRP measurement value of the PC of the user terminal 10 and the repetition number R and the RA preamble based on the first and second association information of the specific PC. ..

As shown in FIGS. 9 and 10, Msg. 3 By determining the number of repetitions R of PUSCH, the user terminal 10 of the PC having a large maximum transmission power is unnecessarily Msg. 3 Since it is possible to prevent PUSCH from repeating, it is possible to improve the utilization efficiency of wireless resources.

The judgment criteria shown in FIGS. 9 and 10 are merely examples, and are not limited to those shown. For example, in FIGS. 9 and 10, two threshold values α and β are shown for each PC, but the number of threshold values may be 1 or more. Of course, the RO or RA preamble associated with each condition is not limited to the one shown in the figure. Further, although the judgment criteria based on the RSRP measured values are shown in FIGS. 9 and 10, it goes without saying that they may be replaced with the measured values of RSRQ. Of course, the above criteria can also be applied during multi-beam operation and / or single-beam operation.

As described above, when the first association information is received for each PC, the control unit 103 has the repetition number R associated with RSRP or RSRQ based on the first association information of the PC of the user terminal 10. May be determined. On the other hand, when the first association information of the specific PC is received, the control unit 103 uses the user terminal based on the first association information and a predetermined rule (for example, a rule based on the predetermined offset Y). The first association information of 10 PCs may be derived, and the number of repetitions R associated with RSRP or RSRQ may be determined based on the derived first association information.

Further, when the second association information is received for each PC, the control unit 103 determines the RO or RA preamble associated with RSRP or RSRQ based on the second association information of the PC of the user terminal 10. You may. On the other hand, when the second association information of the specific PC is received, the control unit 103 uses the user terminal based on the second association information and a predetermined rule (for example, a rule based on the predetermined offset Y). The second association information of 10 PCs may be derived, and the RO or RA preamble associated with RSRP or RSRQ may be determined based on the derived second association information.

In the second embodiment, the transmission unit 201 of the base station 20 may transmit the first association information for each PC, or may transmit the first association information of a specific PC. good. Further, the transmission unit 201 may transmit the second association information for each PC, or may transmit the second association information of a specific PC. The first and second association information does not have to be transmitted separately, and may be transmitted for each PC or for a specific PC as the association information for the association between RSRP or RSRQ, the number of repetitions R, and the RA preamble or RO. good.

The control unit 203 uses the RA preamble received by the reception unit 202 or the RO used for transmitting the RA preamble to obtain Msg. 3 The number of repetitions R of PUSCH may be determined. The base station 20 is Msg. 3. If the PC of the user terminal 10 cannot be recognized at the time of receiving the PUSCH, the association between the RO or RA preamble shown in FIGS. 9 and 10 and the repetition number R may be common among the PCs. As a result, the control unit 203 determines that the PC of the user terminal 10 has Msg. 3 Even if the repetition number R of PUSCH is determined, the base station 20 is determined by RO or RA preamble to Msg. 3 The number of repetitions R of PUSCH can be recognized.

(Operation of wireless communication system)
Next, the operation of the wireless communication system 1 according to the second embodiment will be described. FIG. 11 is a diagram showing an example of the operation of the CBRA according to the second embodiment. The operation shown in FIG. 11 is merely an example, and the order of at least some steps may be changed, omitted, and / or added. In FIG. 11, the differences from FIG. 8 will be described, and the description of the same points will not be repeated. Steps S201, S202, S209 and S210 of FIG. 11 are the same as steps S101, S102, S109 and S110 of FIG.

In step S203 of FIG. 11, the user terminal 10 receives the SIB via the PDSCH. The user terminal 10 may include the first and second association information for each PC included in the SIB, or may include the first and second association information for a specific PC.

In step S204, the user terminal 10 selects the RA preamble or RO based on the RSRP measured value or RSRQ measured value in step S202 and the PC of the user terminal 10 (see, for example, FIGS. 9 and 10).

In step S205, the user terminal 10 uses a certain RO to transmit the RA preamble (message 1) selected in step S204. Alternatively, the user terminal 10 transmits a certain RA preamble (message 1) using the RO selected in step S204.

In step S206, the base station 20 receives the RA preamble received in step S205 or the Msg. 3 Determine the number of repetitions R of PUSCH. In step S207, the base station 20 transmits a RAR message (message 2) for the RA preamble received in step S205. In addition, the content and the number of bits of the upstream grant included in the RAR message are described in Msg. 3 The same number of bits (for example, 27 bits) may be used regardless of the number of repetitions R of PUSCH.

In step S208, the user terminal 10 is based on the RSRP measurement value or RSRQ measurement value in step S202 and the PC of the user terminal 10, and Msg. 3 Determine the number of repetitions R of PUSCH (see, for example, FIGS. 9 and 10). In addition, the user terminal 10 is based on the RO or RA preamble selected in step S204, and Msg. 3 The number of repetitions R of PUSCH may be determined (see, for example, FIGS. 9 and 10).

According to the wireless communication system 1 according to the second embodiment, Msg. 3 Since the repetition number R of PUSCH is determined, the user terminal 10 of the PC having a large maximum transmission power is unnecessarily Msg. 3 PUSCH can be prevented from repeating. As a result, the utilization efficiency of wireless resources can be improved.

(Other embodiments)
The embodiments described above are for facilitating the understanding of the present invention, and are not for limiting and interpreting the present invention. The flowchart, sequence, each element included in the embodiment, its arrangement, material, condition, shape, size, and the like described in the embodiment are not limited to those exemplified, and can be changed as appropriate. In addition, the configurations shown in different embodiments can be partially replaced or combined.

1 ... Wireless communication system, 10 ... User terminal, 20 ... Base station, 30 ... Core network, 101 ... Receiver unit, 102 ... Transmitter unit, 103 ... Control unit, 104 ... Measurement unit, 201 ... Transmitter unit, 202 ... Receiver unit , 203 ... Control unit, 11 ... Processor, 12 ... Memory, 13 ... Storage device, 14 ... Communication device, 15 ... Input device, 16 ... Output device

Claims

A measuring unit that measures received power or reception quality using a synchronous signal block,
A transmitter that sends a random access (RA) preamble,
A receiver that receives a response message to the RA preamble, and
A control unit that determines the number of repetitions of the uplink shared channel used for transmitting the message 3 in response to the response message based on the received power or the reception quality.
User terminal with.
The receiving unit receives the first association information regarding the association between the received power or the reception quality and the number of repetitions.
The control unit determines the received power or the number of repetitions associated with the received quality based on the first association information.
The user terminal according to claim 1.
The receiving unit receives the first association information for each power class, and receives the first association information.
The control unit determines the received power or the number of repetitions associated with the received quality based on the first association information of the power class of the user terminal.
The user terminal according to claim 2.
The receiver receives the first association information of a specific power class and receives the first association information.
The control unit determines the received power or the number of repetitions associated with the reception quality based on the first association information of the power class of the user terminal derived based on the first association information.
The user terminal according to claim 2.
The control unit selects a random access opportunity to use for transmitting the RA preamble or the RA preamble based on the received power or the reception quality.
The user terminal according to any one of claims 1 to 4.
The receiving unit receives the second association information regarding the association between the received power or the reception quality and the RA preamble or the random access opportunity.
The control unit selects the RA preamble or the random access opportunity associated with the received power or the received quality based on the second association information.
The user terminal according to claim 5.
The receiving unit receives the second association information for each power class, and receives the second association information.
The control unit determines the RA preamble or the random access opportunity associated with the received power or the received quality based on the second association information of the power class of the user terminal.
The user terminal according to claim 6.
The receiver receives the second association information of a specific power class and receives the second association information.
The control unit has the RA preamble or the random access associated with the received power or the reception quality based on the second association information of the power class of the user terminal derived based on the second association information. Determine the opportunity,
The user terminal according to claim 6.
Steps to measure received power or received quality using a synchronous signal block,
Steps to send a random access (RA) preamble,
The step of receiving the response message to the RA preamble, and
A step of determining the number of iterations of the uplink shared channel used to transmit the message 3 in response to the response message, based on the received power or the received quality.
A wireless communication method for a user terminal having.