Terminal, base station, communication method and integrated circuit

Abstract

The present invention provides a terminal that improves the efficiency of random access processing. In the terminal (200), a control unit (209) determines a resource for sending a response signal to a downlink signal for the multiple terminals based on parameters set for each of the multiple terminals, and a sending unit (218) sends the response signal in the resource.

Description

Technical Field

[0001] The present invention relates to a terminal and a sending method. Background Art

[0002] The 3rd Generation Partnership Project (3GPP) has completed the development of Release 15 NR (New Radio Access Technology) specifications for the fifth-generation mobile communication system (5G). NR supports ultra-reliable and low-latency communication (URLLC) capabilities, in conjunction with high speed and large capacity, the fundamental requirements of enhanced mobile broadband (eMBB) (see, for example, Non-Patent Documents 1-7).

[0003] Prior art literature

[0004] Non-patent literature

[0005] Non-Patent Document 1: 3GPP TS 38.211 V15.4.0, "NR; Physical channels and modulation (Release 15)," December 2018.

[0006] Non-Patent Document 2: 3GPP TS 38.212 V15.4.0, "NR; Multiplexing and channel coding (Release 15)," December 2018.

[0007] Non-Patent Document 3: 3GPP TS 38.213 V15.4.0, "NR; Physical layer procedure for control (Release 15)," December 2018.

[0008] Non-Patent Document 4: 3GPP TS 38.214 V15.4.0, "NR; Physical layer procedures for data (Release 15)," December 2018.

[0009] Non-Patent Document 5: 3GPP, TS 38.300 V15.4.0, “NR; NR and NG-RAN overall description; Stage 2 (Release 15)”, December 2018.

[0010] Non-Patent Document 6: 3GPP, TS 38.321 V15.4.0, “NR; Medium access control (MAC) protocol specification (Release 15)”, December 2018.

[0011] Non-Patent Document 7: 3GPP, TS 38.331 V15.4.0, “NR; Radio resource control (RRC) protocol specification (Release 15)”, December 2018.

[0012] Non-Patent Literature 8: B. Bertenyi, S. Nagata, H. Kooropaty, X. Zhou, W. Chen, Y. Kim, X. Dai, and X. Xu, “5G NR radio interface,” Journal of ICT, Vol. 6 and 2, pp. 31-58, 2018.

[0013] Non-Patent Document 9: RP-182881, “New work item: 2-step RACH for NR,” ZTE Corporation, Sanechips, December 2018. Summary of the Invention

[0014] However, the random access process has not yet been fully studied.

[0015] Non-limiting embodiments of the present invention help provide a terminal and a transmission method that can improve the efficiency of random access processing.

[0016] A terminal of one embodiment of the present invention includes: a control circuit that determines resources for sending a response signal to a downlink signal based on parameters set separately for each of a plurality of terminals, wherein the downlink signal is a downlink signal for the plurality of terminals; and a sending circuit that sends the response signal in the resources.

[0017] It should be noted that these general or specific aspects may be implemented by a system, device, method, integrated circuit, computer program or recording medium, or by any combination of systems, devices, methods, integrated circuits, computer programs and recording media.

[0018] According to one embodiment of the present invention, the efficiency of random access processing can be improved.

[0019] Further advantages and effects of an embodiment of the present invention will be explained through the description and drawings. These advantages and / or effects are provided by several embodiments and the features described in the description and drawings, but it is not necessary to provide all of them in order to obtain one or more of the same features. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is a diagram showing an example of a four-step random access procedure.

[0021] Figure 2 This is a diagram showing an example of a two-step random access procedure.

[0022] Figure 3 This is a block diagram showing a configuration example of a portion of a terminal according to the first embodiment.

[0023] Figure 4 This is a block diagram showing a configuration example of a base station according to the first embodiment.

[0024] Figure 5 This is a block diagram showing a configuration example of a terminal according to the first embodiment.

[0025] Figure 6 This is a sequence diagram showing an example of operations of the base station and the terminal according to the first embodiment.

[0026] Figure 7 This is a diagram showing an example of a two-step random access procedure according to the first embodiment.

[0027] Figure 8 This is a diagram showing an example of a two-step random access procedure according to the first embodiment.

[0028] Figure 9 This is a diagram showing a structural example of message B.

[0029] Figure 10 This is a diagram showing a structural example of message B. DETAILED DESCRIPTION

[0030] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0031] [Random access process]

[0032] In Release 15 NR, a terminal (also called a "mobile station" or "UE") sends a random access signal (also called a "RACH" or "PRACH") to a base station (also called a "gNB" or "eNB"), for example, in the following situations:

[0033] (1) Initial access (e.g., transition from RRC_IDLE state to RRC_CONNECTED state);

[0034] (2) Recovering from RRC_INACTIVE state to RRC_CONNECTED state;

[0035] (3) When downlink data or uplink data is generated during the connection process (for example, in the RRC_CONNECTED state, when the uplink synchronization state is "non-synchronized");

[0036] (4) Requesting SI (System Information) on demand;

[0037] (5) Recovery from beam connection failure (BFR: Beam failure recovery).

[0038] As a result, the terminal attempts to connect to the base station or re-establish synchronization with the base station. The series of actions performed by the terminal to connect to the base station or re-establish synchronization with the base station is called a "random access procedure."

[0039] In Release 15 NR, the random access procedure is performed by Figure 1 The four-step structure shown (referred to as a "four-step random access procedure" or a "four-step RACH procedure") (for example, refer to non-patent document 8).

[0040] Step 1: Send Message 1

[0041] A terminal (e.g., a UE) randomly selects a PRACH preamble resource to be used from a pool of resource candidates (e.g., resources defined by a combination of time resources, frequency resources, and sequence resources) for a preamble signal (hereinafter also referred to as "RACH preamble," "PRACH preamble," or simply "preamble"). The terminal then transmits the PRACH preamble to a base station (e.g., a gNB) using the selected PRACH preamble resource. The PRACH preamble is sometimes referred to as "Message 1," for example.

[0042] <Step 2: Send Message 2>

[0043] When the base station detects the PRACH preamble, it sends a RACH response (also called a "RAR: Random Access Response"). The RAR is sometimes referred to as "Message 2," for example. Furthermore, at this point in time, the base station cannot identify the terminal that sent the PRACH preamble. Therefore, the RAR is sent, for example, to all cells covered by the base station.

[0044] The RAR includes, for example, information related to the resources (uplink resources) used by the terminal to transmit uplink signals (Step 3: Transmit Message 3) or information related to the terminal's uplink transmission timing. If a terminal that has transmitted a PRACH preamble does not receive the RAR within a predetermined period (e.g., the "RAR reception window") from the timing of transmitting the PRACH preamble, it reselects a PRACH preamble resource and transmits the PRACH preamble (in other words, retransmits Message 1).

[0045] <Step 3: Send Message 3>

[0046] The terminal uses the uplink resources indicated by the base station via the RAR, and transmits "Message 3" including, for example, an RRC (Radio Resource Control) connection request or a scheduling request.

[0047] <Step 4: Send Message 4>

[0048] The base station sends a message (referred to as "Message 4") containing identification information for identifying the terminal (e.g., UE-ID) to the terminal. By sending Message 4, the base station confirms that multiple terminals are not competing (contention resolution). Alternatively, for example, a C-RNTI (Cell-Radio Network Temporary Identifier) ​​or a temporary C-RNTI can be used as the UE-ID.

[0049] An example of a four-step random access procedure has been described above.

[0050] On the other hand, in Release 16NR, in order to allow the terminal to efficiently connect to the base station or re-establish synchronization with the base station with low latency, for example, Figure 2 The random access procedure shown consists of two steps (sometimes also called "two-step random access procedure" or "two-step RACH procedure (2-step RACH procedure)") (for example, refer to Non-Patent Document 9).

[0051] <Step 1: Send Message A>

[0052] The terminal sends the following message to the base station (hereinafter referred to as "message A"), which contains the equivalent of the four-step random access process (for example, refer to Figure 1 ) of step 1 and step 3 (in other words, the preamble) and information equivalent to message 3.

[0053] <Step 2: Send Message B>

[0054] When the base station detects message A, it sends message B. Message B, for example, includes information equivalent to the four-step random access procedure (for example, see Figure 1 ) of message 2 or message 4 (e.g., one or both).

[0055] [Retransmission control during random access]

[0056] During the four-step random access procedure, Message 2 is sent as a multicast (or "multicast") message. For example, Message 2 includes a MAC RAR (or MAC subPDU) for one or more terminals within a MAC PDU (Medium Access Control Layer Protocol Data Unit). Furthermore, retransmission control, or HARQ (Hybrid Automatic Repeat Request), is not applied to Message 2.

[0057] In addition, in the four-step random access process, message 4 is sent as unicast, and HARQ is applied to message 4.

[0058] On the other hand, in the two-step random access process, message B includes at least: a MAC PDU including a RACH response (e.g., RAR) and a MAC PDU including a message (e.g., contention resolution MAC CE) including identification information for identifying the terminal (e.g., UE-ID).

[0059] For example, if message B is sent as unicast, similar to message 4 of the four-step random access procedure, the base station 100 schedules message B via a downlink control channel (e.g., PDCCH: Physical Downlink Control Channel) for all terminals performing random access. In this case, for example, the downlink control channel overhead is likely to increase as the number of terminals performing random access increases.

[0060] Therefore, it is assumed that the transmission of message B is performed as multicast transmission similarly to message 2 of the four-step random access procedure. This can reduce the overhead of the downlink control channel.

[0061] In addition, in addition to the aforementioned MAC PDU containing the RAR and the MAC PDU containing the UE-ID, Message B may also include, for example, a MAC PDU containing RRC signaling related to RRC connection, RRC recovery, and RRC reconnection. Including the MAC PDU containing the RRC signaling in Message B can further reduce the latency of the two-step random access procedure.

[0062] However, RRC signals carry a larger amount of data than other signals. Therefore, it is conceivable to improve downlink resource utilization efficiency by applying HARQ to Message B, similar to Message 4 of the four-step random access procedure. When HARQ is applied to Message B, the terminal transmits a response signal (e.g., ACK / NACK: Acknowledgement / Negative Acknowledgment) to the base station in the uplink, indicating the error detection result of the downlink data (e.g., RRC signal).

[0063] However, a method for transmitting an ACK / NACK signal for the message B multicast-transmitted in the two-step random access procedure has not yet been fully studied.

[0064] For example, in Release 15NR, the allocation of resources (hereinafter referred to as "PUCCH resources") for the uplink control channel (e.g., PUCCH: Physical Uplink control channel) for sending ACK / NACK signals for message 4 is introduced (e.g., refer to non-patent document 3).

[0065] For example, the base station notifies the terminal in advance of a resource configuration (e.g., a PUCCH resource set) representing a combination of multiple parameters related to PUCCH resources through cell-specific higher-layer signals (e.g., RMSI: Remaining Minimum System Information) such as the SIB (System Information Block). For example, in Release 15 NR, a PUCCH resource set includes 16 combinations of parameters related to PUCCH resources.

[0066] In addition, the base station selects a combination of parameters related to the PUCCH resources that a terminal actually uses from the PUCCH resource set based on a portion of the bits within the PDCCH of the scheduling message 4 (for example, 3 bits in version 15NR) and the CCE (Control Channel Element) number as the resource allocation information of the PDCCH.

[0067] For example, the combination of parameters related to PUCCH resources r PUCCH (For example, 16 values ​​from 0 to 15) are obtained by the following formula.

[0068] r PUCCH =ceiling(2n CCE / N CCE )+2Δ PRI (1)

[0069] In formula (1), n CCE Indicates the CCE number, N CCE represents the number of CCEs, Δ PRI Indicates a value (for example, one of values ​​0 to 7) explicitly notified by a portion of bits (for example, 3 bits) in the PDCCH.

[0070] Here, the transmission of message 4 is unicast, so the message 4 for each terminal is scheduled by a different PDCCH. Therefore, for example, the base station appropriately sets the combination of parameters related to PUCCH resources shown in formula (1) and Δ PRITherefore, regarding the ACK / NACK signal for message 4, no conflict of PUCCH resources occurs between terminals.

[0071] On the other hand, when message B is multicast, it contains MAC PDUs for multiple terminals. Therefore, depending on the channel status of each terminal, there may be a mixture of terminals that can correctly decode the MAC PDU and terminals that fail to decode the MAC PDU within the cell. In other words, the decoding results (in other words, ACK / NACK signals) of the MAC PDU of message B (e.g., the MAC PDU containing the RRC signal) at each terminal may differ between terminals.

[0072] However, when message B is multicast, the base station schedules message B, which includes MAC PDUs addressed to multiple terminals, using a single PDCCH. Therefore, for example, if the Release 15NR PUCCH resource allocation for message 4 shown in equation (1) is used, the same PUCCH resources are allocated to all terminals. Therefore, when each terminal transmits an ACK / NACK signal corresponding to the decoding result of the MAC PDU of message B to the base station, all terminals transmit the ACK / NACK signal using the same PUCCH resource. In other words, there is a possibility of PUCCH resource collision between terminals regarding the ACK / NACK signal for message B.

[0073] For example, the base station will PRI (For example, refer to formula (1)) It is included in the PDCCH and sent. As a result, the ACK / NACK signal for message B can suppress the collision of PUCCH resources between terminals. However, in this case, the overhead of PDCCH increases. For example, assuming that the Δ PRI If , an overhead of 3 bits will be generated, which is the number of terminals (in other words, the number of users).

[0074] Here, in one embodiment of the present invention, a method for transmitting an ACK / NACK signal for message B in a two-step random access process when message B is multicast is described. According to one embodiment of the present invention, PDCCH overhead can be reduced and PUCCH resource conflicts between terminals can be suppressed.

[0075] Hereinafter, each embodiment will be described in detail.

[0076] (Implementation 1)

[0077] [Overview of the Communication System]

[0078] The communication system according to each embodiment of the present invention includes a base station 100 and a terminal 200 .

[0079] Figure 3 1 is a block diagram showing a configuration example of a portion of the terminal 200 according to each embodiment of the present invention. Figure 3 In the illustrated terminal 200, control unit 209 (equivalent to a control circuit) determines resources for transmitting response signals (e.g., ACK / NACK signals) to downlink signals (e.g., Message B) addressed to the multiple terminals based on parameters configured for each of the multiple terminals. Transmitter 218 transmits the response signals using these resources.

[0080] [Structure of base station]

[0081] Figure 4 : is a block diagram showing a configuration example of a base station 100 according to Embodiment 1 of the present invention. Figure 4 In the figure, the base station 100 includes a control unit 101, a data generation unit 102, a coding unit 103, a retransmission control unit 104, a modulation unit 105, a high-layer control signal generation unit 106, a coding unit 107, a modulation unit 108, a downlink control signal generation unit 109, a coding unit 110, a modulation unit 111, a signal distribution unit 112, an IFFT (Inverse Fast Fourier Transform) unit 113, a transmitting unit 114, an antenna 115, a receiving unit 116, an FFT (Fast Fourier Transform) unit 117, an extraction unit 118, a detection unit 119, a demodulation unit 120 and a decoding unit 121.

[0082] The control unit 101 determines the information required for the terminal 200 to transmit message A (or also referred to as "message A transmission parameters") and outputs the determined information to the extraction unit 118, demodulation unit 120, and decoding unit 121. Furthermore, the control unit 101 outputs the determined information to the higher-layer control signal generation unit 106. The information used to transmit message A may include, for example, information related to the PRACH preamble resources, PUSCH resources, and the PUSCH transport block size (TBS) or MCS (Modulation and Coding Scheme) of message A.

[0083] Furthermore, the control unit 101 determines radio resource allocation (e.g., downlink resources and MCS) for data signals (e.g., message B), higher-layer control signals (e.g., higher-layer control signals), or downlink signals used to transmit downlink control information (e.g., downlink control signals). The control unit 101 outputs the determined information (e.g., including scheduling information) to the coding units 103, 107, and 110, the modulation units 105, 108, and 111, and the signal allocation unit 112. Furthermore, the control unit 101 outputs the determined information to the downlink control signal generation unit 109.

[0084] In addition, the control unit 101 determines the information included in the message B based on the decoding result of the message A (for example, C-Plane (control plane) data or UP (User Plane) data) input from the decoding unit 121 and the detection result of the message A (for example, PRACH preamble code) input from the detection unit 119, and outputs the determined information to the data generation unit 102.

[0085] Furthermore, the control unit 101 determines information on PUCCH resources for the terminal 200 to transmit an ACK / NACK signal for message B. The control unit 101 outputs the determined information to the higher layer control signal generation unit 106 , the downlink control signal generation unit 109 , the data generation unit 102 , or the extraction unit 118 .

[0086] The data generation unit 102 generates an information bit string of the message B (in other words, downlink data) using the information included in the message B input from the control unit 101 , and outputs the generated information bit string to the encoding unit 103 .

[0087] The coding unit 103 performs error correction coding on the information bit sequence (data signal) input from the data generation unit 102 , and outputs the coded data signal to the retransmission control unit 104 .

[0088] During initial transmission, the retransmission control unit 104 outputs the encoded data signal input from the encoding unit 103 to the modulation unit 105. Furthermore, the retransmission control unit 104 retains the encoded data signal. Furthermore, when a NACK for the transmitted data signal is input from the decoding unit 121, the retransmission control unit 104 outputs the corresponding retained data to the modulation unit 105. When an ACK for the transmitted data signal is input, the retransmission control unit 104 deletes the corresponding retained data.

[0089] The modulation unit 105 modulates the data signal input from the retransmission control unit 104 and outputs the modulated data signal to the signal distribution unit 112 .

[0090] The higher layer control signal generation unit 106 generates a control information bit sequence (higher layer control signal) using the control information input from the control unit 101 , and outputs the generated control information bit sequence to the coding unit 107 .

[0091] The coding unit 107 performs error correction coding on the control information bit sequence input from the higher layer control signal generation unit 106 , and outputs the coded control signal to the modulation unit 108 .

[0092] The modulation unit 108 modulates the control signal input from the encoding unit 107 and outputs the modulated control signal to the signal distribution unit 112 .

[0093] The downlink control signal generating unit 109 generates a control information bit string (a downlink control signal, for example, DCI (Downlink Control Information)) using the control information input from the control unit 101, and outputs the generated control information bit string to the coding unit 110. Furthermore, because control information may be sent to multiple terminals, the downlink control signal generating unit 109 may scramble the control information for each terminal (for example, PDCCH (Physical Downlink Control Channel)) using identification information for all terminals (for example, RA-RNTI (Random Access-RNTI)) or terminal-specific identification information (for example, C-RNTI).

[0094] The coding unit 110 performs error correction coding on the control information bit sequence input from the downlink control signal generation unit 109 , and outputs the coded control signal to the modulation unit 111 .

[0095] The modulation unit 111 modulates the control signal input from the encoding unit 110 and outputs the modulated control signal to the signal distribution unit 112 .

[0096] Signal allocation section 112 maps the data signal input from modulation section 105, the higher layer control signal input from modulation section 108, or the downlink control signal input from modulation section 111 to the radio resources based on the information indicating the radio resources input from control section 101. Signal allocation section 112 outputs the downlink signal to which the signal is mapped to IFFT section 113.

[0097] The IFFT unit 113 performs transmission waveform generation processing such as OFDM (Orthogonal Frequency Division Multiplexing) on ​​the signal input from the signal distribution unit 112. In the case of OFDM transmission with a CP (Cyclic Prefix) added, the IFFT unit 113 adds a CP (not shown). The IFFT unit 113 outputs the generated transmission waveform to the transmitter 114.

[0098] The transmitter 114 performs RF (Radio Frequency) processing such as D / A (Digital-to-Analog) conversion and up-conversion on the signal input from the IFFT unit 113 , and transmits the wireless signal to the terminal 200 via the antenna 115 .

[0099] The receiving unit 116 performs RF processing such as down-conversion or A / D (Analog-to-Digital) conversion on the uplink signal waveform received from the terminal 200 via the antenna 115 , and outputs the processed uplink signal waveform to the FFT unit 117 .

[0100] The FFT unit 117 performs FFT processing on the uplink signal waveform input from the receiving unit 116 to convert the time domain signal into a frequency domain signal. The FFT unit 117 outputs the frequency domain signal obtained by the FFT processing to the extracting unit 118.

[0101] Extraction unit 118 extracts the radio resource portion where the PRACH preamble was transmitted, or the radio resource portion where the PUSCH of message A was transmitted, from the signal input from FFT unit 117, based on the information input from control unit 101. Extraction unit 118 outputs the extracted radio resource portion where the PRACH preamble was transmitted to detection unit 119, and outputs the radio resource portion where a signal other than the PRACH preamble (e.g., the PUSCH of message A) was transmitted to demodulation unit 120. Furthermore, extraction unit 118 extracts the ACK / NACK signal for message B from the signal input from FFT unit 117, based on the information input from control unit 101, and outputs it to demodulation unit 120.

[0102] The detection unit 119 detects the PRACH preamble on the radio resource portion corresponding to the PRACH preamble input from the extraction unit 118. The detection unit 119 outputs information on the detection result of the PRACH preamble to the control unit 101.

[0103] The demodulation unit 120 demodulates the data of the message A or the ACK / NACK signal for the message B input from the extraction unit 118 based on the information input from the control unit 101 , and outputs the demodulation result (demodulated sequence) to the decoding unit 121 .

[0104] Decoding unit 121 performs error correction decoding on the demodulation result input from demodulation unit 120 based on the information input from control unit 101, and outputs the decoded bit sequence (e.g., including C-Plane data or UP data). For example, decoding unit 121 outputs the decoding result of message A to control unit 101.

[0105] Furthermore, decoding unit 121 decodes the ACK / NACK signal for message B based on the demodulation result input from demodulation unit 120 and determines whether the ACK / NACK signal for the transmitted data signal represents ACK or NACK. Decoding unit 121 outputs the determination result (ACK or NACK) to retransmission control unit 104.

[0106] [Structure of the terminal]

[0107] Figure 5 2 is a block diagram showing a configuration example of a terminal 200 according to an embodiment of the present invention. Figure 5 In the figure, the terminal 200 includes an antenna 201, a receiving unit 202, an FFT unit 203, an extraction unit 204, a demodulation unit 205, a decoding unit 206, a downlink control signal demodulation unit 207, a decoding unit 208, a control unit 209, a PRACH preamble code generation unit 210, an ACK / NACK generation unit 211, a coding unit 212, a modulation unit 213, a coding unit 214, a modulation unit 215, a signal distribution unit 216, an IFFT unit 217 and a transmitting unit 218.

[0108] The receiving unit 202 performs RF processing such as down-conversion or A / D (Analog-to-Digital) conversion on the signal waveform of the downlink signal received from the base station 100 via the antenna 201, and outputs the obtained received signal (baseband signal) to the FFT unit 203. The downlink signal includes, for example, a data signal (e.g., Message B), a higher layer control signal, or a downlink control signal.

[0109] The FFT unit 203 performs FFT processing to convert the time domain signal into a frequency domain signal on the signal (time domain signal) input from the receiving unit 202. The FFT unit 203 outputs the frequency domain signal obtained by the FFT processing to the extraction unit 204.

[0110] Extraction unit 204 extracts a data signal (e.g., message B), a downlink control signal, or a higher-layer control signal from the signal input from FFT unit 203 based on control information (e.g., information related to the radio resource of the control signal) input from control unit 209. Extraction unit 204 outputs the data signal or higher-layer control signal to demodulation unit 205 and outputs the downlink control signal to downlink control signal demodulation unit 207.

[0111] The demodulation unit 205 demodulates the data signal or the higher-layer control signal input from the extraction unit 204 , and outputs the demodulation result to the decoding unit 206 .

[0112] Decoding section 206 performs error correction decoding using the demodulation result input from demodulation section 205, thereby obtaining received data (e.g., message B) or control information. Decoding section 208 outputs the obtained received data or control information to control section 209. Decoding section 206 also performs error detection on the received data and outputs the error detection result (e.g., error presence or absence) to ACK / NACK generation section 211.

[0113] The downlink control signal demodulation unit 207 demodulates the downlink control signal input from the extraction unit 204 and outputs the demodulation result to the decoding unit 208 .

[0114] The decoding unit 208 performs error correction decoding using the demodulation result input from the downlink control signal demodulation unit 207 to obtain control information. The decoding unit 208 outputs the obtained control information to the control unit 209.

[0115] The control unit 209 determines parameters related to uplink transmission (e.g., transmission of message A) based on the control information input from the decoding unit 206 or the decoding unit 208. The control unit 209 outputs the determined information to the PRACH preamble code generation unit 210, the coding units 212 and 214, the modulation units 213 and 215, and the signal allocation unit 216.

[0116] Furthermore, the control unit 209 determines information related to the transmission of the ACK / NACK signal (e.g., uplink resources, transmission method, parameters, etc.) based on the information related to the resource for transmitting the ACK / NACK signal for message B input from the decoding unit 206 or the decoding unit 208. The control unit 209 outputs the determined information to the coding unit 212, the modulation unit 213, and the signal allocation unit 216.

[0117] Furthermore, the control unit 209 outputs information on the radio resource of the control signal included in the control information input from the decoding unit 206 or the decoding unit 208 to the extraction unit 204 .

[0118] The PRACH preamble generation unit 210 generates a PRACH preamble based on the control information (eg, transmission parameters of message A) input from the control unit 209 , and outputs the generated PRACH preamble to the signal allocation unit 216 .

[0119] The ACK / NACK generation unit 211 generates an ACK / NACK signal for the received downlink data (e.g., message B) based on the error detection result input from the decoding unit 206 , and outputs the ACK / NACK signal (e.g., ACK / NACK signal sequence) to the encoding unit 212 .

[0120] The encoding unit 212 performs error correction coding on the ACK / NACK signal sequence input from the ACK / NACK generation unit 211 based on the information input from the control unit 209 (for example, information related to the transmission of the ACK / NACK signal), and outputs the encoded ACK / NACK signal sequence to the modulation unit 213.

[0121] The modulation unit 213 modulates the ACK / NACK signal sequence input from the coding unit 212 based on the information input from the control unit 209 , and outputs the modulated ACK / NACK signal (modulation symbol sequence) to the signal distribution unit 216 .

[0122] The encoding unit 214 performs error correction encoding on the information bit sequence (e.g., C-Plane data and UP data) sent in the data part of message A based on the control information input from the control unit 209 (e.g., the transmission parameters of message A), and outputs the encoded bit sequence to the modulation unit 215.

[0123] The modulation unit 215 modulates the bit sequence input from the coding unit 214 based on the information input from the control unit 209 , and outputs a data signal (modulation symbol sequence) to the signal distribution unit 216 .

[0124] The signal allocation unit 216 maps the signal input from the PRACH preamble code generation unit 210, the signal input from the modulation unit 213, or the signal input from the modulation unit 215 to the wireless resources instructed by the control unit 209, and outputs the uplink signal to which the signal is mapped to the IFFT unit 217.

[0125] The IFFT unit 217 performs OFDM or other transmission waveform processing on the signal input from the signal distribution unit 216. For OFDM transmission with a CP, the IFFT unit 217 adds a CP (not shown). Alternatively, if the IFFT unit 217 generates a single-carrier waveform, a DFT (Discrete Fourier Transform) unit (not shown) may be added upstream of the signal distribution unit 216. The IFFT unit 217 outputs the generated transmission waveform to the transmitter 218.

[0126] The transmission unit 218 performs RF processing such as D / A conversion and up-conversion on the signal input from the IFFT unit 217 , and transmits the wireless signal to the base station 100 via the antenna 201 .

[0127] [Operation Example of Base Station 100 and Terminal 200]

[0128] An operation example of the base station 100 and the terminal 200 having the above configuration will be described.

[0129] Figure 6 An example of a flow related to the transmission and reception processing of an ACK / NACK signal for message B in base station 100 and terminal 200 according to this embodiment is shown.

[0130] exist Figure 6 In the present embodiment, base station 100 notifies terminal 200 of information related to uplink resources (e.g., PUCCH resources) (ST101). The information related to PUCCH resources includes, for example, information related to PUCCH resources used to transmit ACK / NACK signals for message B. Terminal 200 obtains the information related to PUCCH resources (ST102).

[0131] The base station 100 transmits scheduling information including allocation information of the message B to the terminal 200 (ST103). The scheduling information of the message B may be transmitted via the PDCCH, for example. The terminal 200 obtains the scheduling information of the message B (ST104).

[0132] For example, based on the scheduling information of the message B, the base station 100 transmits the message B to the terminal 200 (ST105).

[0133] After receiving message B, terminal 200 demodulates and decodes message B (ST106). In addition, terminal 200 generates an ACK / NACK signal for message B.

[0134] Terminal 200 determines uplink resources for sending ACK / NACK signals for message B (e.g., RRC signals) based on information related to PUCCH resources, scheduling information (e.g., PDCCH), and at least one of message B (e.g., RAR) (ST107).

[0135] Next, terminal 200 transmits an ACK / NACK signal for message B to base station 100 based on the determined uplink resources (ST108).

[0136] [Method of Transmitting ACK / NACK Signal for Message B]

[0137] Next, an example of a method of transmitting an ACK / NACK signal for message B will be described.

[0138] In this embodiment, terminal 200 transmits an ACK / NACK signal for message B on, for example, the PUCCH.

[0139] In this case, in addition to notifying the PUCCH resource for transmitting the ACK / NACK signal for message 4 of the four-step random access procedure (e.g., the parameter shown in equation (1)), terminal 200 also determines the PUCCH resource for transmitting the ACK / NACK signal for message B based on the new parameter "X." Parameter X may be a value set for each of the multiple terminals 200 that are the destinations for message B, for example.

[0140] First, operation examples 1 and 2 of the two-step RACH procedure in this embodiment will be described below.

[0141] Here, as an example, a case is described in which three terminals 200 (e.g., UE#A, UE#B, and UE#C) send message A to a base station 100 (e.g., gNB).

[0142] [Action Example 1]

[0143] Figure 7 An example of a two-step RACH procedure in operation example 1 is shown.

[0144] <Sending Message A>

[0145] Each terminal 200 transmits a message A to the base station 100 .

[0146] Message A includes, for example, a RACH preamble (e.g., one of preambles #1 to #3) and a PUSCH (e.g., a data portion or a UCI + data portion). Furthermore, the PUSCH includes, for example, a UE-ID for identifying terminal 200 (e.g., one of UE-ID #A, UE-ID #B, and UE-ID #C).

[0147] Furthermore, each terminal 200 operates a "Msg. B reception window" (in other words, a timer), which is a period during which message B can be received, from the timing of transmitting the RACH preamble (in other words, message A).

[0148] <Sending Message B>

[0149] When the base station 100 detects and correctly decodes the message A transmitted from each terminal 200 , it transmits a message B. The message B includes, for example, a message including a RAR and a UE-ID for identifying the terminal 200 (eg, a MAC RAR and a MAC CE).

[0150] On the other hand, if the base station 100 fails to detect message A (e.g., PRACH preamble code) or fails to correctly decode message A (e.g., PUSCH), it will not include information sent to the terminal 200 that sent the corresponding message A in message B.

[0151] For example, in Figure 7 In the example shown, base station 100 (gNB) detects preamble #1 of message A transmitted from UE #A (detection result: ○) and correctly decodes the PUSCH (decoding result: ○). Meanwhile, base station 100 (gNB) detects preamble #2 of message A transmitted from UE #B (detection result: ○) and fails to correctly decode the PUSCH (decoding result: ×). Furthermore, base station 100 (gNB) fails to detect preamble #1 of message A transmitted from UE #C (detection result: ×) and fails to correctly decode the PUSCH (decoding result: ×).

[0152] Therefore, in Figure 7 In the example shown, the base station 100 generates a message B including the RAR for UE#A and the UE-ID#A of UE#A. In other words, Figure 7 Message B does not contain information sent to UE#B and UE#C.

[0153] Receiving Message B

[0154] If the terminal 200 that has sent message A does not receive message B containing information addressed to the terminal 200 within the Msg.B reception window, it resends message A (in other words, it performs random access processing again from the time message A is sent). Figure 7 In the example shown, UE#B and UE#C do not receive message B addressed to UE#B and UE#C within the Msg.B reception window, and therefore retransmit message A.

[0155] On the other hand, when the terminal 200 that sent the message A receives the message B containing information addressed to the terminal 200 during the Msg.B reception window, and the UE-ID contained in the message B is consistent with the UE-ID contained in the sent message A, it is determined that the RACH process has succeeded. Figure 7 In the example shown, UE#A receives message B sent to UE#A during the Msg.B reception window, and the UE-ID (UE-ID#A) contained in message B is consistent with the UE-ID (UE-ID#A) contained in the sent message A. Therefore, it is judged that the RACH process has been successful (RA process: ○).

[0156] <Action Example 2>

[0157] Figure 8 An example of a two-step RACH procedure in operation example 2 is shown.

[0158] <Sending Message A>

[0159] Each terminal 200 transmits a message A to the base station 100 .

[0160] As in Example 1, message A includes, for example, a RACH preamble (e.g., one of preambles #1 to #3) and a PUSCH (e.g., a data portion or a UCI + data portion). Furthermore, the PUSCH includes, for example, a UE-ID for identifying terminal 200 (e.g., one of UE-ID #A, UE-ID #B, and UE-ID #C).

[0161] Furthermore, each terminal 200 operates a "Msg. B reception window" (in other words, a timer), which is a period during which message B can be received, from the timing of transmitting the RACH preamble (in other words, message A).

[0162] <Sending Message B>

[0163] When the base station 100 detects and correctly decodes the message A transmitted from each terminal 200 , it transmits a message B. The message B includes, for example, a message including a RAR and a UE-ID for identifying the terminal 200 (eg, a MAC RAR and a MAC CE).

[0164] Furthermore, if base station 100 detects the RACH preamble of message A transmitted from each terminal 200 but fails to correctly decode the data portion, it may also transmit message B. If base station 100 detects the RACH preamble but fails to correctly decode the data portion, it cannot identify the terminal 200 that transmitted the RACH preamble at that point in time. Therefore, in this case, for example, message B includes a RAR (in other words, it does not include a UE-ID). The RAR may also include, for example, information related to a retransmission request requesting the terminal 200 that transmitted the corresponding RACH preamble to retransmit the data portion, as well as information related to resources used in the uplink.

[0165] On the other hand, when base station 100 fails to detect message A (for example, a PRACH preamble), it does not include information addressed to terminal 200 that has transmitted the corresponding message A in message B.

[0166] For example, in Figure 8 In the example shown, the same as in Action Example 1 (for example, Figure 7 ) Similarly, base station 100 (gNB) detects preamble #1 of message A transmitted from UE#A (detection result: o) and correctly decodes the PUSCH (decoding result: o). Meanwhile, base station 100 (gNB) detects preamble #2 of message A transmitted from UE#B (detection result: o) but cannot correctly decode the PUSCH (decoding result: x). Furthermore, base station 100 (gNB) cannot detect preamble #1 of message A transmitted from UE#C (detection result: x) and cannot correctly decode the PUSCH (decoding result: x).

[0167] Therefore, in Figure 8 In the example shown, the base station 100 generates a message B including the RAR for UE#A, UE-ID#A of UE#A, and the RAR for UE#B. Figure 7 In the example, message B does not contain information sent to UE#C.

[0168] Receiving Message B

[0169] If the terminal 200 that has sent message A does not receive message B containing information addressed to the terminal 200 within the Msg.B reception window, it resends message A (in other words, it performs random access processing again from the time message A is sent). Figure 8 In the example shown, UE#C does not receive message B addressed to UE#C within the Msg. B reception window, and therefore retransmits message A.

[0170] On the other hand, if the terminal 200 that has sent message A receives message B containing information addressed to the terminal 200 within the Msg.B reception window, but the UE-ID contained in message B does not match the UE-ID contained in the sent message A, the terminal 200 performs uplink transmission based on the information contained in the RAR corresponding to message A (for example, the PRACH preamble). Figure 8 In the example shown, although UE#B receives Message B (e.g., RAR) addressed to UE#B within the Msg.B receive window, the UE-ID (UE-ID#A) included in Message B does not match the UE-ID (UE-ID#B) included in the previously transmitted Message A. Therefore, UE#B determines that the RACH procedure has not been successful (RA procedure: x). For example, UE#B can retransmit the PUSCH based on the information included in the RAR for UE#B in Message B. In other words, UE#B can fallback to sending Message 3 of the four-step random access procedure.

[0171] In addition, when the terminal 200 that sent the message A receives the message B containing the information sent to the terminal 200 during the Msg.B reception window, and the UE-ID contained in the message B is consistent with the UE-ID contained in the sent message A, it is determined that the RACH process has been successful. Figure 8 In the example shown, UE#A receives message B sent to UE#A during the Msg.B reception window, and the UE-ID (UE-ID#A) contained in message B is consistent with the UE-ID (UE-ID#A) contained in the sent message A. Therefore, it is judged that the RACH process has been successful (RA process: ○).

[0172] The above describes the operation examples 1 and 2 of the two-step random access procedure.

[0173] As described above, when base station 100 detects message A and decodes it correctly, message B includes a MAC PDU including RAR and a MAC PDU including a message (eg, contention resolution MAC CE) for identifying terminal 200 UE-ID.

[0174] Furthermore, the MAC PDU including the RAR may include, for example, information on the transmission timing of the uplink signal in the terminal 200 , TC-RNTI (Temporary C-RNTI), or information on resources used by the terminal 200 in the uplink.

[0175] In addition, in addition to the RAR and the MAC PDU containing the UE-ID, the message B may also include, for example, a MAC PDU containing RRC signals for RRC connection, RRC recovery, and RRC reconnection.

[0176] Figure 9 and Figure 10 This section shows an example structure of message B. Figure 9 This shows an example of a case where the MAC PDU including the RRC signaling is not included in the message B. Figure 10 This shows an example in which message B includes a MAC PDU containing an RRC signal.

[0177] For example, when the terminal 200 receives a message B containing information addressed to the terminal 200, and the UE-ID contained in the message B is consistent with the UE-ID contained in the sent message A, and the message B includes a MAC PDU containing an RRC signal addressed to the terminal 200, the terminal 200 decodes the MAC PDU containing the RRC signal and sends an ACK / NACK signal corresponding to the decoding result (or error detection result) to the base station 100 in an uplink resource (e.g., a PUCCH resource).

[0178] The following describes a method for determining PUCCH resources for transmitting ACK / NACK signals.

[0179] The base station 100 notifies the terminal 200 in advance of a resource configuration (e.g., a PUCCH resource set) indicating a combination of multiple parameters related to PUCCH resources, for example, through a cell-specific higher-layer signal (e.g., RMSI) such as an SIB. For example, in Release 15 NR, a PUCCH resource set includes 16 combinations of parameters related to PUCCH resources. In addition, the number of combinations of parameters related to PUCCH resources included in a PUCCH resource set is not limited to 16 and may be another number.

[0180] In addition, the base station 100 selects a combination of parameters related to the PUCCH resources that are actually used by a terminal 200 from the PUCCH resource set based on a portion of the bits within the PDCCH of the scheduling message B (for example, 3 bits in version 15NR), the CCE number of the PDCCH, and the newly added notification information "X".

[0181] For example, the combination of parameters related to PUCCH resources r PUCCH (For example, 16 values ​​from 0 to 15) are obtained by the following formula.

[0182] r PUCCH =ceiling(2n CCE / N CCE )+2Δ PRI+X (2)

[0183] In formula (2), n CCE Indicates the CCE number, N CCE represents the number of CCEs, Δ PRI Indicates the value explicitly notified by 3 bits of PDCCH (one of the values ​​0 to 7). PRI The number of bits is not limited to 3 for PDCCH, and may be another number of bits.

[0184] In this way, the terminal 200 performs the calculation based on the value (eg, Δ PRI ), the resource to which the PDCCH is allocated (eg, n CCE ) and the parameter "X" set by terminal 200, the uplink resource for transmitting the ACK / NACK signal is determined. In other words, terminal 200 determines the PUCCH resource for transmitting the ACK / NACK signal for message B based on the following method (for example, see equation (2)), which is different from the method for determining the PUCCH resource for transmitting the ACK / NACK signal for message 4 of the four-step random access procedure (for example, see equation (1)).

[0185] In formula (2), parameter "X" can be explicitly or implicitly notified from base station 100 to terminal 200 through the following method (one of options 1 to 5 or a combination of options 1 to 5), for example.

[0186] <Option 1>

[0187] Parameter "X" may also be included in the MAC RAR of message B (in other words, information related to the response to message A (PRACH preamble)).

[0188] The MAC PDU including the RAR may include, in addition to the parameter "X", information related to the uplink transmission timing of the terminal 200, TC-RNTI, or information related to resources used by the terminal 200 in the uplink.

[0189] Option 2

[0190] The parameter “X” may also be a value associated with the UE-ID included in the message A sent by the terminal 200 .

[0191] For example, the association may be performed in the form of X = UE-ID mod Y. Here, Y is the number of combinations of multiple parameters related to PUCCH resources included in the PUCCH resource set. In Release 15 NR, Y = 16.

[0192] Option 3

[0193] The parameter “X” may be a value associated with the arrangement order of the RARs corresponding to the plurality of terminals 200 in the message B (for example, referred to as “RAR order”).

[0194] For example, in Figure 10 In the message B shown, RAR is included in the order of MAC subPDU3A, MAC subPDU4A, ... In addition, Figure 10 In the illustrated message B, the RRC signal addressed to the terminal 200 corresponding to the MAC subPDU3A is included in the MAC subPDU3C, and the RRC signal addressed to the terminal 200 corresponding to the MAC subPDU4A is included in the MAC subPDU4C.

[0195] In this case, for example, X may be set to 0 for the terminal 200 corresponding to MAC subPDU3C (e.g., the first RAR), and X may be set to 1 for the terminal 200 corresponding to MAC subPDU4C (e.g., the second RAR), based on the order (arrangement order) of the RARs included in message B. The number of RARs included in message B and the value of X associated with the arrangement order of the RARs are not limited to these values.

[0196] <Option 4>

[0197] The parameter “X” may also be a value associated with the RACH preamble code number (eg, PAID) used by the message A sent by the terminal 200 .

[0198] For example, the association may be performed in the form of X = PAID mod Y. Here, Y is the number of combinations of multiple parameters related to PUCCH resources included in the PUCCH resource set. In Release 15 NR, Y = 16.

[0199] Option 5

[0200] The parameter “X” may also be a value associated with a port number (eg, DMRS port number) of a reference signal (eg, DMRS: Demodulation Reference Signal) of the PUSCH used by the message A sent by the terminal 200 .

[0201] For example, the association may be performed in the form of X=DMRS port index mod Y. Here, Y is the number of combinations of multiple parameters related to PUCCH resources included in the PUCCH resource set. In Release 15 NR, Y=16.

[0202] The above describes the notification method of the parameter "X" (option 1 to option 5).

[0203] According to the above five options, the parameter "X" can be notified to the terminal 200 without increasing the overhead of the PDCCH.

[0204] In addition, for example, according to equation (2) including the parameter "X", each terminal 200 can select a combination r of parameters related to PUCCH resources for each terminal 200. PUCCH In other words, terminal 200 can independently determine the PUCCH resource for transmitting the ACK / NACK signal for message B (in other words, a signal addressed to multiple terminals 200) transmitted by multicast based on parameter "X" configured for each terminal 200. This makes it possible to suppress PUCCH resource conflicts between terminals 200 when transmitting the ACK / NACK signal for message B (e.g., an RRC signal).

[0205] Therefore, according to this embodiment, even when message B (e.g., including an RRC signal) is multicasted, it is possible to suppress PUCCH resource conflicts between terminals 200 when transmitting ACK / NACK signals for the RRC signal without increasing PDCCH overhead. Thus, according to this embodiment, the efficiency of random access processing (e.g., retransmission control) in message B of the two-step random access procedure can be improved.

[0206] In addition, one of the above options 1 to 5 may be adopted, or a combination of multiple options may be adopted.

[0207] In addition, this embodiment is not limited to the case where terminal 200 uses parameter "X" to determine the PUCCH in addition to a portion of bits (for example, 3 bits in Release 15 NR) in the PDCCH of scheduling message B and the CCE number as the PDCCH resource allocation information. For example, terminal 200 may also use parameter "X" to determine the PUCCH resource without using a portion of bits and CCE numbers in the PDCCH of scheduling message B. In this case, PDCCH overhead can be further reduced.

[0208] Furthermore, when multiple transmission methods, including multicast and unicast, are supported for message B, terminal 200 may determine PUCCH resources according to the transmission method of message B. For example, when multicast transmission is configured for message B, terminal 200 may use parameter "X" to determine PUCCH resources (for example, refer to equation (2)), and when unicast transmission is configured for message B, terminal 200 may determine PUCCH resources without using parameter "X" (for example, refer to equation (1)).

[0209] (Implementation Method 2)

[0210] The basic structure of the base station and the terminal of this embodiment is the same as that of the base station 100 and the terminal 200 of the embodiment 1. Figure 4 and Figure 5 Provide explanation.

[0211] In this embodiment, terminal 200 transmits an ACK / NACK signal for message B on an uplink control channel (eg, PUCCH).

[0212] At this time, the base station 100 notifies the terminal 200 of the PUCCH resource for transmitting the ACK / NACK signal, for example, using the uplink allocation information (e.g., called "UL grant") included in the RAR of message B. The terminal 200 determines the PUCCH resource for transmitting the ACK / NACK signal for message B (e.g., RRC signal) based on the UL grant included in the RAR of message B sent to the terminal 200.

[0213] For example, in the operation example 2 of the two-step random access procedure in embodiment 1 (for example, refer to Figure 8 ), when the base station 100 detects the message A and decodes it correctly, it transmits the message B. In this case, the message B includes a message including the RAR and the UE-ID for identifying the terminal 200.

[0214] In this embodiment, when base station 100 detects and correctly decodes message A, it notifies the uplink resources (e.g., PUCCH resources) used to transmit an ACK / NACK signal for message B (e.g., an RRC signal) in the UL grant included in the RAR. For example, terminal 200 receives message B containing information addressed to terminal 200. If the UE-ID included in message B matches the UE-ID transmitted in message A and message B includes a MAC PDU containing an RRC signal addressed to terminal 200, terminal 200 decodes the MAC PDU and transmits the decoding result (e.g., an ACK / NACK signal) to base station 100 using the PUCCH resources notified by the UL grant.

[0215] For example, in Figure 8In the example shown, base station 100 (gNB) detects preamble #1 of message A transmitted from UE#A (detection result: ○) and correctly decodes the PUSCH (decoding result: ○). Therefore, base station 100 configures the PUCCH resources for transmitting the ACK / NACK signal for message B in the UL grant included in the RAR for UE#A in message B. UE#A transmits the ACK / NACK signal for message B based on the PUCCH resources indicated in the UL grant included in the RAR for UE#A in message B.

[0216] In addition, in the operation example 2 of the two-step random access procedure of embodiment 1 (for example, refer to Figure 8 ), even if base station 100 detects the RACH preamble of message A but fails to correctly decode the data portion, it may transmit message B. In this case, message B includes a RAR. The RAR may include, for example, information related to a retransmission request for terminal 200 that has transmitted the corresponding RACH preamble to retransmit the data portion, and information related to resources used by terminal 200 in the uplink (UL grant).

[0217] In this embodiment, for example, the base station 100 detects the message A ( Figure 8 If the UE 200 receives the RACH preamble of message A) of UE#B in the RAR and fails to correctly decode the data part, the UL grant included in the RAR notifies the uplink resources (e.g., PUSCH resources) for retransmitting the data part (e.g., PUSCH) in message A. Figure 8 UE#B in message B) retransmits the data portion of message A (eg, PUSCH) based on the PUSCH resources indicated by the UL grant included in the RAR of message B for terminal 200.

[0218] In addition, the RAR may also include a flag that identifies whether uplink resources for retransmitting message A (for example, PUSCH) are notified through UL grant, or PUCCH resources for transmitting an ACK / NACK signal for message B are notified.

[0219] In Release 15 NR, for example, the UL grant included in the RAR consists of a 27-bit field. In this embodiment, for example, a portion of the 27-bit field included in the UL grant may be used to notify the PUCCH resource used to transmit the ACK / NACK signal for message B. Furthermore, the size of the field included in the UL grant is not limited to 27 bits.

[0220] For example, similar to Release 15 NR, when the number of combinations of multiple parameters related to PUCCH resources included in a PUCCH resource set is 16, 4 bits may be used to notify the PUCCH resource used to transmit the ACK / NACK signal for message B, and the remaining field may be used for other purposes or set as a reserved field. Furthermore, the number of bits used to notify PUCCH resources is not limited to 4 bits.

[0221] According to this embodiment, the base station 100 notifies the PUCCH resource for transmitting the ACK / NACK signal for message B through the UL grant included in the RAR of message B. In other words, the base station 100 can individually set (in other words, schedule) the PUCCH resource for each terminal 200 in the UL grant included in the RAR of message B for each terminal 200.

[0222] Thus, terminal 200 can independently determine the PUCCH resource for transmitting an ACK / NACK signal for a multicast message B (in other words, a signal addressed to multiple terminals 200) based on the UL grant configured for each terminal 200. Therefore, when transmitting the ACK / NACK signal for message B (e.g., an RRC signal), collision of PUCCH resources between terminals 200 can be suppressed.

[0223] Furthermore, base station 100 does not notify PUCCH resources using PDCCH (in other words, DCI), and thus PDCCH overhead can be reduced.

[0224] (Implementation 3)

[0225] The basic structure of the base station and the terminal of this embodiment is the same as that of the base station 100 and the terminal 200 of the embodiment 1. Figure 4 and Figure 5 Provide explanation.

[0226] In this embodiment, terminal 200 transmits an ACK / NACK signal for message B on an uplink data channel (eg, PUSCH).

[0227] At this time, the base station 100 notifies the terminal 200 of the PUSCH resources for transmitting the ACK / NACK signal, for example, using the UL grant included in the RAR of message B. The terminal 200 determines the PUSCH resources for transmitting the ACK / NACK signal for message B (for example, the RRC signal), for example, based on the UL grant included in the RAR of message B sent to the terminal 200.

[0228] For example, in the operation example 2 of the two-step random access procedure in embodiment 1 (for example, refer to Figure 8 ), when the base station 100 detects the message A and decodes it correctly, it transmits the message B. In this case, the message B includes a message including the RAR and the UE-ID for identifying the terminal 200.

[0229] In this embodiment, when base station 100 detects and correctly decodes message A, it notifies the uplink resources (e.g., PUSCH resources) used to transmit an ACK / NACK signal for message B (e.g., an RRC signal) in the UL grant included in the RAR. For example, terminal 200 receives message B containing information addressed to terminal 200, and when the UE-ID included in message B matches the UE-ID transmitted in message A, and when message B includes a MAC PDU containing an RRC signal addressed to terminal 200, the terminal decodes the MAC PDU and transmits the decoding result (e.g., an ACK / NACK signal) to base station 100 using the PUSCH resources notified by the UL grant.

[0230] For example, in Figure 8 In the example shown, base station 100 (gNB) detects preamble #1 of message A transmitted from UE#A (detection result: ○) and correctly decodes the PUSCH (decoding result: ○). Therefore, base station 100 configures PUSCH resources for transmitting the ACK / NACK signal for message B in the UL grant included in the RAR for UE#A in message B. UE#A transmits the ACK / NACK signal for message B based on the PUSCH resources indicated in the UL grant included in the RAR for UE#A in message B.

[0231] In addition, in the operation example 2 of the two-step random access procedure of embodiment 1 (for example, refer to Figure 8 ), even if base station 100 detects the RACH preamble of message A but fails to correctly decode the data portion, it may transmit message B. In this case, message B includes a RAR. The RAR may include, for example, information related to a retransmission request for terminal 200 that has transmitted the corresponding RACH preamble to retransmit the data portion, and information related to resources used by terminal 200 in the uplink (UL grant).

[0232] In this embodiment, for example, the base station 100 detects the message A ( Figure 8 If the UE 200 receives the RACH preamble of message A) of UE#B in the RAR and fails to correctly decode the data part, the UL grant included in the RAR notifies the uplink resources (e.g., PUSCH resources) for retransmitting the data part (e.g., PUSCH) in message A. Figure 8UE#B in message B retransmits the data portion of message A (eg, PUSCH) based on the PUSCH resources indicated by the UL grant contained in the RAR of message B sent to terminal 200.

[0233] In addition, in this embodiment, for example, there is no need to Figure 6 The processing of sending and obtaining information related to the PUCCH resources used to send ACK / NACK for message B (for example, the processing of ST101 and ST102).

[0234] In addition, as a mapping method of the ACK / NACK signal in the PUSCH, for example, one of the following two methods may be adopted.

[0235] The first method is to map the ACK / NACK signal to the PUSCH using the same method as the data portion, similarly to the UL-SCH (UL Shared Channel). In this case, the ACK / NACK signal is transmitted according to the MCS notified by the UL grant.

[0236] The second method is to map the ACK / NACK signal to the PUSCH, for example, by utilizing the method of multiplexing UCI (Uplink Control Information) on the PUSCH in Release 15 NR when there is no UL-SCH (see, for example, Non-Patent Documents 2 and 3). In this case, the ACK / NACK signal may be transmitted using a lower MCS than the MCS notified by the UL grant.

[0237] According to this embodiment, the base station 100 notifies the PUSCH resource for transmitting the ACK / NACK signal for message B through the UL grant included in the RAR of message B. In other words, the base station 100 can individually set (in other words, schedule) the PUSCH resource for each terminal 200 in the UL grant included in the RAR of message B for each terminal 200.

[0238] Thus, terminal 200 can independently determine the PUSCH resource for transmitting an ACK / NACK signal for a multicast message B (in other words, a signal addressed to multiple terminals 200) based on the UL grant configured for each terminal 200. Therefore, it is possible to suppress PUSCH resource conflicts between terminals 200 when transmitting the ACK / NACK signal for message B (e.g., an RRC signal).

[0239] Furthermore, base station 100 does not need to notify PUSCH resources using PDCCH (in other words, DCI), and thus PDCCH overhead can be reduced.

[0240] Furthermore, in this embodiment, the UL grant included in the RAR of message B notifies the PUSCH resources used to retransmit message A (e.g., PUSCH) or the PUSCH resources used to transmit the ACK / NACK signal for message B. In other words, in this embodiment, regardless of the detection and decoding results of message A in base station 100, the resources notified in the RAR of message B are all PUSCH resources. Therefore, according to this embodiment, there is no need to change the information notified by the UL grant in the RAR based on the decoding results of message A in base station 100, thereby simplifying the structure of the RAR.

[0241] One embodiment of the present invention has been described above.

[0242] In the above embodiments, the case where the terminal 200 transmits an ACK / NACK signal (ACK or NACK) for the message B has been described. However, the terminal 200 may transmit a NACK to the base station 100 when the decoding of the message B has failed, but may not transmit an ACK to the base station 100 when the decoding of the message B has succeeded.

[0243] For example, terminal 200 determines that the random access operation has been successfully completed when it correctly decodes the PDCCH of scheduling message B and correctly decodes the MAC PDU included in message B. Terminal 200 does not transmit an ACK to base station 100 .

[0244] On the other hand, when terminal 200 correctly decodes the PDCCH of scheduling message B but fails to correctly decode the MAC PDU included in message B, terminal 200 transmits a NACK to base station 100 to request retransmission of message B.

[0245] Alternatively, terminal 200 may start a timer from the time a NACK is sent. If base station 100 successfully receives the NACK sent by terminal 200, it retransmits message B. On the other hand, if base station 100 fails to receive the NACK sent by terminal 200, it determines that terminal 200 has successfully received message B and cannot retransmit message B. In this case, if the timer starting from the time a NACK is sent exceeds a certain period, terminal 200 resumes the RACH operation.

[0246] In this way, since the terminal 200 does not send ACK, the overhead of uplink resources can be reduced, thereby reducing the power consumption of the terminal 200.

[0247] Furthermore, in each of the above embodiments, the terminal 200 may transmit an ACK to the base station 100 when decoding of the message B is successful, but may not transmit a NACK to the base station 100 when decoding of the message B fails.

[0248] For example, if message B includes a MAC PDU containing a RAR and a MAC PDU containing a message (e.g., a contention resolution MAC CE) containing identification information for identifying a terminal (e.g., a UE-ID), terminal 200 cannot identify whether the message B it is attempting to decode is addressed to its own terminal if decoding of message B fails. Therefore, terminal 200 may not send a NACK to base station 100.

[0249] The present invention can be implemented by software, hardware, or software in collaboration with hardware. The functional blocks used in the description of the above embodiments are partially or entirely implemented as LSIs (Large Scale Integration) as integrated circuits. The various processes described in the above embodiments may also be partially or entirely controlled by a single LSI or a combination of LSIs. An LSI may be composed of individual chips, or may be composed of a single chip that includes some or all of the functional blocks. An LSI may also include data input and output. Depending on the degree of integration, an LSI may also be referred to as an "IC (Integrated Circuit)", "System LSI", "Super LSI", or "Ultra LSI". The method of integrated circuitization is not limited to LSI, and may also be implemented by dedicated circuits, general-purpose processors, or dedicated processors. In addition, an FPGA (Field Programmable Gate Array) that can be programmed after LSI manufacturing, or a reconfigurable processor that can reconfigure the connections or settings of circuit blocks within the LSI may also be used. The present invention may also be implemented as digital processing or analog processing. Furthermore, if semiconductor technology advances or other technologies evolve and a technology for integrated circuits emerges that replaces LSIs, it would be possible to use this technology to integrate functional blocks. There is also the possibility of applying biotechnology, etc.

[0250] The present invention can be implemented in all types of devices, equipment, and systems (collectively referred to as "communication devices") that have communication functions. The communication device may also include a wireless transceiver and processing / control circuits. The wireless transceiver may also include a receiving unit and a transmitting unit, or perform the functions of these units. The wireless transceiver (transmitting unit, receiving unit) may also include an RF (Radio Frequency) module and one or more antennas. The RF module may also include an amplifier, an RF modulator / demodulator, or devices similar to these. Non-limiting examples of communication devices include: telephones (mobile phones, smartphones, etc.), tablet computers, personal computers (PCs) (laptops, desktops, notebook computers, etc.), cameras (digital cameras, digital video cameras, etc.), digital players (digital audio / video players, etc.), wearable devices (wearable cameras, smart watches, tracking devices, etc.), game consoles, e-book readers, telehealth / telemedicine (telehealth / medical prescription) equipment, vehicles with communication functions or transportation vehicles (cars, airplanes, ships, etc.), and combinations of the above devices.

[0251] Communication devices are not limited to portable or mobile devices. They also include all types of devices, equipment, and systems that cannot be portable or fixed. Examples include smart home devices (appliances, lighting, smart meters or meters, control panels, etc.), vending machines, and all other "things" that can exist on an IoT (Internet of Things) network.

[0252] The communication includes data communication performed by a cellular system, a wireless LAN (Local Area Network) system, a communication satellite system, etc., and also includes data communication performed by a combination of these systems.

[0253] Furthermore, the communication device also includes devices such as controllers and sensors that are connected or coupled to the communication equipment performing the communication functions described in the present invention. For example, the communication device may include a controller or sensor that generates control signals or data signals used by the communication equipment performing the communication functions of the communication device.

[0254] In addition, the communication device includes infrastructure equipment that communicates with or controls the above-mentioned non-limiting various devices, such as base stations, access points, and all other devices, equipment, and systems.

[0255] A terminal of one embodiment of the present invention includes: a control circuit that determines, based on parameters set separately for each of a plurality of terminals, resources for sending a response signal to a downlink signal, the downlink signal being a downlink signal for the plurality of terminals; and a sending circuit that sends the response signal in the resources.

[0256] In one embodiment of the present invention, the control circuit determines the resource based on a value notified by control information related to the downlink signal, a resource to which the control information is allocated, and the parameter.

[0257] In one embodiment of the present invention, the downlink signal includes information related to responses to random access signals transmitted by each of the plurality of terminals, and the parameter is included in the information related to the response.

[0258] In one embodiment of the present invention, the downlink signal includes information related to a response to a random access signal transmitted by each of the plurality of terminals, and the parameter represents a value associated with information included in the random access signal for identifying each of the plurality of terminals.

[0259] In one embodiment of the present invention, the downlink signal includes information related to a response to a random access signal sent by each of the multiple terminals, and the parameter represents a value associated with a configuration order of the following information in the downlink signal, wherein the information is information related to the response corresponding to each of the multiple terminals.

[0260] In one embodiment of the present invention, the downlink signal includes information related to responses to random access signals transmitted by each of the plurality of terminals, and the parameter represents a value associated with a preamble number used by the random access signal.

[0261] In one embodiment of the present invention, the downlink signal includes information related to a response to a random access signal sent by each of the multiple terminals, the random access signal includes a preamble code part and a data part, and the parameter represents a value associated with a port number of a reference signal used by the data part.

[0262] In one embodiment of the present invention, the downlink signal includes information related to responses to random access signals transmitted by each of the plurality of terminals, and the parameter is uplink resource allocation information included in the information related to the response.

[0263] In one embodiment of the present invention, the resource is an uplink control resource.

[0264] In one embodiment of the present invention, the resource is an uplink data resource.

[0265] The sending method of one embodiment of the present invention includes the following steps: determining, based on parameters set separately for each of a plurality of terminals, resources for sending a response signal to a downlink signal, wherein the downlink signal is a downlink signal for the plurality of terminals; and sending the response signal in the resources.

[0266] The disclosure of Japanese Patent Application No. 2019-061499 filed on March 27, 2019, including the specification, drawings, and abstract, is incorporated herein by reference in its entirety.

[0267] Industrial Applicability

[0268] One embodiment of the present invention is useful for a mobile communication system.

[0269] Description of Reference Numerals

[0270] 100 base stations

[0271] 101, 209 Control Department

[0272] 102 Data Generation Unit

[0273] 103, 107, 110, 212, 214 Coding Department

[0274] 104 Retransmission Control Unit

[0275] 105, 108, 111, 213, 215 modulation unit

[0276] 106 High-level control signal generation unit

[0277] 109 Downlink control signal generating unit

[0278] 112, 216 Signal Distribution Department

[0279] 113, 217 IFFT Department

[0280] 114, 218 Sending Department

[0281] 115, 201 antenna

[0282] 116, 202 Receiving Department

[0283] 117, 203 FFT Department

[0284] 118, 204 Extraction Department

[0285] 119 Testing Department

[0286] 120, 205 demodulation unit

[0287] 121, 206, 208 Decoding Unit

[0288] 200 Terminal

[0289] 207 Downlink control signal demodulation unit

[0290] 210 PRACH preamble code generation unit

[0291] 211 ACK / NACK generation unit

Claims

1. A terminal, characterized in that: include: The control circuit determines, based on a first parameter included in a message B, a resource for sending a response signal to the message B, wherein the message B is a response to the sending of the random access signal; as well as a sending circuit, sending the response signal in the resource, When the message B requests retransmission of the data portion of the random access signal, the transmission circuit transmits the message 3 using another resource, the another resource being the resource notified by the message B. The control circuit determines the resource based on the first parameter in a manner not using bits of a physical downlink control channel (PDCCH) and control channel element numbers (CCE numbers), The number of bits of the first parameter included in the message B is greater than the number of bits of the parameter included in the PDCCH.

2. The terminal according to claim 1, wherein: The control circuit determines the resource from a plurality of resources based on the first parameter, and the plurality of resources are notified by a higher layer signal.

3. The terminal according to claim 1, wherein: The message B also includes sending timing information for sending the response signal.

4. The terminal according to claim 1, wherein: When the message B includes the identification information of the terminal, the control circuit determines that the random access procedure has succeeded.

5. The terminal according to claim 1, wherein: When the message B requests retransmission of the data portion of the random access signal, the message B does not include identification information of the terminal.

6. The terminal according to claim 1, wherein: After sending the random access signal, the control circuit starts a window associated with the message B, When the message B is not received within the window, the transmitting circuit retransmits the random access signal.

7. The terminal according to claim 1, wherein: For one or more terminals whose preamble part of the random access signal is not detected by the base station, the message B does not include control information of the one or more terminals.

8. The terminal according to claim 1, wherein: The random access signal includes both a random access channel preamble, ie, a RACH preamble, and a physical uplink shared channel, ie, a PUSCH.

9. A base station, characterized in that: include: A control circuit determines a resource for sending a response signal to a message B, wherein the message B is a response to the sending of the random access signal; a sending circuit, using the message B to send a first parameter representing the resource to the terminal, wherein the message B includes a retransmission request for the data part of the random access signal and uplink resource information; as well as a receiving circuit, receiving message 3 in another resource, wherein the another resource is a resource notified by the uplink resource information, The resource is represented by the first parameter in a manner that bits of a physical downlink control channel (PDCCH) and control channel element numbers (CCE numbers) are not used, The number of bits of the first parameter included in the message B is greater than the number of bits of the parameter included in the PDCCH.

10. The base station according to claim 9, wherein: The control circuit determines the resource from a plurality of resources, and the plurality of resources are notified by a higher layer signal.

11. The base station according to claim 9, wherein: The message B also includes sending timing information for sending the response signal.

12. The base station according to claim 9, wherein: The message B includes identification information of the terminal indicating that the random access procedure of the terminal has succeeded.

13. The base station according to claim 9, wherein: When the message B requests retransmission of the data portion of the random access signal, the message B does not include identification information of the terminal.

14. The base station according to claim 9, wherein: When the message B is not sent within the window associated with the message B, the receiving circuit receives a retransmission of the random access signal.

15. The base station according to claim 9, wherein: For one or more terminals whose preamble part of the random access signal is not detected by the base station, the message B does not include control information of the one or more terminals.

16. The base station according to claim 9, wherein: The random access signal includes both a random access channel preamble, ie, a RACH preamble, and a physical uplink shared channel, ie, a PUSCH.

17. A communication method implemented by a terminal, characterized in that: The following steps are involved: Determining, based on a first parameter included in a message B, a resource for sending a response signal to the message B, the message B being a response to the sending of the random access signal; and sending the response signal in the resource, When the message B requests retransmission of the data portion of the random access signal, the message 3 is transmitted using another resource, the another resource being the resource notified by the message B, determining the resource based on the first parameter in a manner that does not use bits of a physical downlink control channel (PDCCH) and control channel element numbers (CCE numbers), The number of bits of the first parameter included in the message B is greater than the number of bits of the parameter included in the PDCCH.

18. A communication method implemented by a base station, characterized in that: The following steps are involved: determining a resource for sending a response signal to a message B, wherein the message B is a response to the sending of the random access signal; as well as sending a first parameter representing the resource to the terminal in the message B, The message B includes a retransmission request for the data portion of the random access signal and uplink resource information, receiving a message 3 in another resource, the another resource being a resource notified by the uplink resource information, The resource is represented by the first parameter in a manner that bits of a physical downlink control channel (PDCCH) and control channel element numbers (CCE numbers) are not used, The number of bits of the first parameter included in the message B is greater than the number of bits of the parameter included in the PDCCH.

19. An integrated circuit implemented in a terminal, characterized in that: include: a control circuit for controlling a decision on resources for sending a response signal to a message B based on a first parameter included in the message B, the message B being a response to the sending of the random access signal; as well as The sending circuit controls the following sending, in which the response signal is sent in the resource, When the message B requests retransmission of the data portion of the random access signal, the transmission circuit transmits the message 3 using another resource, the another resource being the resource notified by the message B. The control circuit determines the resource based on the first parameter in a manner not using bits of a physical downlink control channel (PDCCH) and control channel element numbers (CCE numbers), The number of bits of the first parameter included in the message B is greater than the number of bits of the parameter included in the PDCCH.

20. An integrated circuit implemented in a base station, characterized in that: include: a control circuit for controlling a decision of resources for sending a response signal to a message B, the message B being a response to the sending of the random access signal; a transmitting circuit configured to control the following transmission, wherein a first parameter indicating the resource is transmitted in the message B, wherein the message B includes a retransmission request of a data part of the random access signal and uplink resource information; as well as a receiving circuit, receiving message 3 in another resource, wherein the another resource is a resource notified by the uplink resource information, The resource is represented by the first parameter in a manner that bits of a physical downlink control channel (PDCCH) and control channel element numbers (CCE numbers) are not used, The number of bits of the first parameter included in the message B is greater than the number of bits of the parameter included in the PDCCH.

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