Infrastructure facilities and network systems

Abstract

To provide a transmission device, a reception device, a transmission method, and a reception method that appropriately perform a random-access process.SOLUTION: A base station that is an infrastructure facility includes a control information generation part that generates and outputs resource information regarding a preamble part and data part in a Message A. The resource information includes a first preamble number included in a group A to be used when a first number of antenna ports is applied to the data part and a second preamble number included in a group B to be used when a second number of antenna ports is applied to the data part.SELECTED DRAWING: Figure 11

Description

Technical Field

[0001] The present disclosure relates to a transmission device, a reception device, a transmission method, and a reception method.

Background Art

[0002] In the standardization of 5G, a new radio access technology (NR: New Radio access technology) that is not necessarily backward compatible with LTE / LTE-Advanced is being discussed in 3GPP.

[0003] As a random access procedure in NR, in addition to the four-step random access (also called 4-step RACH (Random Access Channel)), the introduction of a two-step random access (also called 2-step RACH) is being considered (see, for example, Non-Patent Document 1 and Non-Patent Document 2).

Prior Art Documents

Non-Patent Documents

[0004]

Non-Patent Document 1

Non-Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, the random access method in NR has not been sufficiently studied.

[0006] Non-limiting embodiments of the present disclosure contribute to providing a transmission device, a reception device, a transmission method, and a reception method that can appropriately perform random access processing.

Means for Solving the Problem

[0007] A transmission device according to an embodiment of the present disclosure includes a transmission circuit that transmits a random access signal including at least a data part, and a control circuit that controls the configuration of the data part based on a parameter related to the transmission of the random access signal.

[0008] These general or specific aspects may be implemented in a system, an apparatus, a method, an integrated circuit, a computer program, or a recording medium, or may be implemented in any combination of a system, an apparatus, a method, an integrated circuit, a computer program, and a recording medium.

Advantages of the Invention

[0009] According to an embodiment of the present disclosure, random access processing can be appropriately performed.

[0010] Further advantages and effects in an embodiment of the present disclosure will be clarified from the specification and the drawings. Such advantages and / or effects are provided by some embodiments and the features described in the specification and the drawings, respectively, but not all of them are necessarily provided in order to obtain one or more identical features.

Brief Description of the Drawings

[0011]

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Embodiments for Carrying Out the Invention

[0012] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings.

[0013] [Random Access Procedure] There are, for example, two procedures (or types, hereinafter referred to as "RACH type") in the random access procedure: CBRA (Contention Based Random Access) and CFRA (Contention Free Random Access).

[0014] [CBRA] FIG. 1(a) shows an example of the 4-step random access of CBRA (also referred to as 4-step CBRA).

[0015] As shown in FIG. 1(a), a terminal (also referred to as a UE (User Equipment)) transmits a Preamble to a base station (for example, referred to as a gNB) in the first-stage transmission (MSG1). After receiving and decoding MSG1, the base station notifies the terminal of a response to the Preamble (for example, also referred to as an RA response), scheduling information including the uplink transmission timing of MSG3, etc. in the second-stage transmission (MSG2). After receiving and decoding MSG2, the terminal notifies the base station of information related to the terminal (for example, terminal ID, etc.) and information used for Connection establishment (or also referred to as RRC (Radio Resourece Control) connection) using the scheduling information indicated in MSG2 in the third-stage transmission (MSG3). Finally, the base station notifies the terminal of a Connection establishment response, etc. in the fourth-stage transmission (MSG4).

[0016] FIG. 1(b) shows an example of two-step random access of CBRA (also referred to as 2-step CBRA).

[0017] As shown in FIG. 1(b), a terminal (UE) transmits a Preamble part (for example, corresponding to the Preamble or MSG1 in FIG. 1(a)) and a Data part (for example, corresponding to MSG3 in FIG. 1(a)) to a base station (gNB) in the first-stage transmission (for example, referred to as "msg A"). The terminal may transmit the Preamble part and the Data part of msg A simultaneously, continuously over time, or within a specified time (for example, within one slot).

[0018] Next, as shown in FIG. 1(b), after receiving and decoding msg A, the base station notifies the terminal of the uplink transmission timing and Connection establishment response, etc. (corresponding to MSG2 and MSG4 in FIG. 1(a)) in the second-stage transmission (hereinafter referred to as "msg B").

[0019] In NR, by introducing two-step random access as shown in Fig. 1(b), for example, a reduction effect of the delay time of random access in services for ultra-high reliability and low latency (e.g., URLLC: Ultra Reliable and Low Latency Communications) is expected.

[0020] Note that in two-step random access, the method in which the terminal transmits the Preamble part and the Data part simultaneously, continuously, or within a specified time as the transmission of msg A is also applicable to CFRA described later.

[0021] [CFRA] Fig. 2(a) shows an example of CFRA.

[0022] As shown in Fig. 2(a), the transmission of the first-stage Preamble (MSG1) is triggered by the downlink control information (e.g., DCI: Downlink Control Information) from the base station for the terminal. The terminal transmits MSG1 to the base station based on the DCI from the base station. After receiving and decoding MSG1, the base station notifies the terminal of information such as the uplink transmission timing in the second-stage transmission (MSG2).

[0023] Fig. 2(b) shows an example of the two-step random access of CFRA (also sometimes referred to as 2-step CFRA).

[0024] As shown in Fig. 2(b), when the transmission of the first stage (msg A) is triggered by DCI from the base station for the terminal, in the transmission of the first stage (msg A), the terminal transmits the Preamble part and the Data part to the base station simultaneously, continuously, or within a specified time (e.g., 1 slot) in the same manner as in the case of CBRA (e.g., refer to Fig. 1(b)). After receiving and decoding msg A, the base station notifies the terminal of the uplink transmission timing and the like in the second-stage transmission (msg B).

[0025] Note that the introduction of the above-described two-stage random access is not limited to the licensed band. For example, in NR, similar to License Assisted Access (LAA), the operation of the Physical Random Access Channel (PRACH) in the unlicensed band is also assumed. By introducing the two-stage random access into the unlicensed band, for example, a reduction effect of the Listen Before Talk (LBT) process is expected.

[0026] [PRACH] PRACH (e.g., MSG1 in Fig. 1(a) or Fig. 2(a)) is composed of a Cyclic Prefix (CP), a Preamble, and a Guard Period (GP). The Preamble is generated from, for example, a code sequence with good correlation characteristics (e.g., Cyclic shifted Zadoff-Chu (CS-ZC) sequence). Also, the CP is a signal obtained by copying a part of the Preamble. The GP is a transmission-free period. Note that the Preamble is not limited to the CS-ZC sequence, and any code sequence with good correlation characteristics may be used.

[0027] The information regarding these PRACHs is notified to the terminal as, for example, cell information of the base station. For example, different CS-ZC sequences are uniquely associated with each Preamble number. In CBRA, for example, the terminal transmits, as the Preamble, the CS-ZC sequence corresponding to the randomly selected Preamble number from among a plurality of Preamble numbers (referred to as "Preamble number group"). Also, in CFRA, for example, the terminal transmits, as the Preamble, the CS-ZC sequence corresponding to the Preamble number indicated by DCI from the base station.

[0028] For example, even when multiple terminals transmit PRACH using the same time resource and frequency resource, if the multiple terminals select different Preamble numbers respectively, the base station can simultaneously detect a plurality of Preamble numbers (in other words, the Preambles of multiple terminals) by correlation detection of the CS-ZC sequences.

[0029] The time resource and frequency resource of the PRACH are notified to the terminal, for example, using higher layer signaling (also referred to as RRC signaling or higher layer parameter). Also, multiple time resources and frequency resources may be notified to the terminal. In this case, in CBRA, the terminal selects the resource to be used for the PRACH from among the multiple notified resources based on the specified conditions.

[0030] The random access procedure has been described above.

[0031] By the way, in NR, in the two-step random access, the details of the frame format of the Data part included in msg A have not been fully discussed. In particular, the configuration of the reference signal (e.g., Demodulation Reference Signal (DMRS)) of the Data part of msg A and multi-layer transmission have not been fully discussed.

[0032] Therefore, below, the method for setting the configuration (in other words, the frame format) of the Data part when the terminal transmits the PRACH in the two-step random access will be described.

[0033] In the following description, "two-step random access" means a random access procedure in which the Preamble part (corresponding to MSG1 in the four-step random access) and the Data part (corresponding to MSG3 in the four-step random access) are transmitted simultaneously, transmitted in consecutive radio resources, or transmitted in radio resources within a specified time (e.g., within a slot). In other words, two-step random access means a random access procedure in which the Data part is transmitted together with the Preamble part. Or, two-step random access means a random access procedure in which the terminal transmits the Data part before receiving a response to the Preamble (corresponding to MSG2 in the four-step random access), or transmits the Data part without waiting for a response to the Preamble.

[0034] (Embodiment 1) In order to improve the reception quality of the Data part of msg A in two-step random access, for example, transmit diversity may be applied to the Data part. Examples of transmit diversity include SFBC (Space Frequency Block Coding) or random precoding.

[0035] Also, in order to transmit more information in the Data part, the terminal may perform MIMO (Multiple Input Multiple Output) transmission of the data in the Data part using multiple layers (Layer or rank). In this case, in order for the base station to decode the signal of the Data part, a demodulation reference signal (DMRS) is required for each of a plurality of antenna ports (also called Antenna port). The DMRS for each antenna port needs to be transmitted using, for example, orthogonal resources (e.g., frequency, time, and code resources).

[0036] Here, in the two-stage random access of CBRA, the base station cannot determine from which terminal msg A is transmitted unless it decodes the Data part of msg A. Depending on the performance of the terminal (e.g., UE capability), there are terminals that support only one antenna. Therefore, in CBRA, the base station cannot instruct all terminals to transmit with multiple antenna ports.

[0037] On the other hand, in the two-stage random access of CFRA, when the base station instructs the terminal to transmit msg A, it notifies the preamble number used for the transmission of msg A. Therefore, in the preamble detection process, the base station can identify the terminal that transmitted msg A (e.g., PRACH) from the detected preamble number. Therefore, in CFRA, the base station can instruct each terminal to transmit with one or more antenna ports.

[0038] Therefore, in this embodiment, the rank number of the Data part (or the rank value, also referred to as the number of layers) is set according to the type of random access procedure (RACH Type) such as CBRA and CFRA.

[0039] [Overview of the communication system] A communication system according to an embodiment of the present disclosure includes a terminal 100 and a base station 200. In the following description, as an example, the terminal 100 (corresponding to a transmission device) transmits a PRACH, and the base station 200 (corresponding to a reception device) receives the PRACH.

[0040] FIG. 3 is a block diagram showing a partial configuration of the terminal 100 according to an embodiment of the present disclosure. In the terminal 100 shown in FIG. 3, the wireless transmission unit 111 (e.g., corresponding to a transmission circuit) transmits a random access signal (e.g., PRACH) including at least a data part (e.g., Data part). The rank determination unit 107 (e.g., corresponding to a control circuit) controls the configuration (e.g., the number of ranks) of the data part based on parameters (e.g., RACH type, etc.) related to the transmission of the random access signal.

[0041] FIG. 4 is a block diagram showing a partial configuration of the base station 200 according to an embodiment of the present disclosure. In the base station 200 shown in FIG. 4, the radio receiving unit 205 (for example, corresponding to a receiving circuit) receives a random access signal (for example, PRACH) including at least a data part (for example, Data part). The rank determination unit 208 controls the configuration of the data part (for example, the number of ranks) based on parameters related to the transmission of the random access signal.

[0042] [Configuration of the terminal] FIG. 5 is a block diagram showing the configuration of the terminal 100 according to the present embodiment.

[0043] In FIG. 5, the terminal 100 includes an antenna 101, a radio receiving unit 102, a demodulation and decoding unit 103, a RACH type determination unit 104, a preamble generation unit 105, a preamble resource allocation unit 106, a rank determination unit 107, a data generation unit 108, a reference signal generation unit 109, a data resource allocation unit 110, and a radio transmission unit 111.

[0044] The radio receiving unit 102 performs reception processing such as down-conversion and A / D conversion on the received signal received from the base station 200 via the antenna 101, and outputs the received signal obtained by the reception processing to the demodulation and decoding unit 103.

[0045] The received signal received from the base station 200 may include, for example, a signal in random access (for example, msg B shown in FIG. 1(b) or FIG. 2(b)), higher layer signaling, or downlink control information (for example, DCI).

[0046] The demodulation and decoding unit 103 demodulates and decodes the received signal input from the radio receiving unit 102. The demodulation and decoding unit 103 outputs the decoded signal (for example, downlink control information) to the RACH type determination unit 104.

[0047] The RACH type determination unit 104 determines the type of random access procedure (RACH type) based on the downlink control information input from the demodulation and decoding unit 103.

[0048] For example, when the downlink control information instructs the transmission of random access (PRACH), the RACH type determination unit 104 determines the RACH type as "CFRA". For example, the RACH type determination unit 104 may determine the RACH type as CFRA when, in the downlink control information, the CRC (Cyclic Redundancy Check) of DCI format1_0 in NR is scrambled using the C-RNTI (Cell-Radio Network Temporary Identifier) and the "Frequency domain resource assignment" field is all 1.

[0049] Also, for example, when the downlink control information does not instruct the transmission of random access, the RACH type determination unit 104 determines the RACH type as "CBRA". For example, the RACH type determination unit 104 may determine the RACH type as CBRA when transmitting a PRACH (in other words, a random access signal) in a two-step random access led by the terminal 100.

[0050] The RACH type determination unit 104 outputs RACH type information indicating the determined RACH Type (for example, either CBRA or CFRA) to the Preamble generation unit 105, the rank determination unit 107, and the Data generation unit 108.

[0051] When the RACH type indicated by the RACH type information input from the RACH type determination unit 104 is CBRA, the Preamble generation unit 105 randomly selects one Preamble number from, for example, a group of Preamble numbers. On the other hand, when the RACH type indicated by the RACH type information is CFRA, the Preamble generation unit 105 selects, for example, the Preamble number notified by downlink control information. The Preamble generation unit 105 generates a CS-ZC sequence using, for example, the sequence number and cyclic shift amount (CS amount) corresponding to the selected Preamble number, and outputs the generated CS-ZC sequence to the Preamble resource allocation unit 106 as a Preamble part signal (or preamble signal). Here, if the selected Preamble numbers are different, the Preamble generation unit 105 generates different code sequences (such as CS-ZC sequences) with small orthogonality or correlation.

[0052] The Preamble resource allocation unit 106 allocates the Preamble part signal input from the Preamble generation unit 105 to at least one of the frequency resources notified by upper layer signaling. Further, the Preamble resource allocation unit 106 outputs the Preamble part signal to the wireless transmission unit 111 based on the set transmission timing.

[0053] The rank determination unit 107 determines the rank (or number of layers) of the Data part based on the RACH Type (for example, CBRA or CFRA) indicated by the RACH type information input from the RACH type determination unit 104. The rank determination unit 107 outputs rank information indicating the determined rank to the Data generation unit 108 and the Data resource allocation unit 110. An example of the rank determination method in the rank determination unit 107 will be described later.

[0054] The Data generation unit 108 generates a data signal (Data part signal) based on the RACH type information input from the RACH type determination unit 104 and the rank information input from the rank determination unit 107. For example, in the case of CBRA, the Data generation unit 108 generates a data signal (e.g., corresponding to MSG3 in the four-step random access) including information used for connection establishment such as the terminal ID. Also, for example, in the case of CFRA, the Data generation unit 108 generates a data signal including a BFR (Beam Failure Report) or a handover completion message. Further, the Data generation unit 108 performs control such as transmit diversity or precoding based on the rank indicated by the rank information. Then, the Data generation unit 108 encodes and modulates the generated data signal and outputs the modulated signal (data sequence) to the Data resource allocation unit 110.

[0055] The reference signal generation unit 109 generates, for example, a reference signal for data demodulation (e.g., DMRS), performs control such as precoding, and outputs the reference signal to the Data resource allocation unit 110. The reference signal may be generated, for example, from a PN sequence or a CS-ZC sequence. Note that, for example, in the reception processing at the base station 200, if the Preamble can be used for channel estimation, the terminal 100 does not need to generate a reference signal.

[0056] The Data resource allocation unit 110 allocates the Data part signal input from the Data generation unit 108 to a frequency resource indicated by, for example, upper layer signaling or downlink control information. Also, the Data resource allocation unit 110 calculates the number of antenna ports based on the rank indicated by the rank information input from the rank determination unit 107. Then, the Data resource allocation unit 110 allocates the reference signal input from the reference signal generation unit 109 to the time, frequency, or code resource corresponding to the antenna ports of the calculated number of antenna ports. Further, the Data resource allocation unit 110 outputs the Data part signal and the reference signal to the wireless transmission unit 111 based on the set transmission timing.

[0057] The wireless transmission unit 111 performs transmission processing such as D / A conversion and up-conversion on the Preamble part signal input from the Preamble resource allocation unit 106, the Data part signal input from the Data resource allocation unit 110, and the reference signal. The wireless transmission unit 111 transmits the wireless signal obtained by the transmission processing (for example, corresponding to the PRACH (or msg A) of the two-step random access (see Fig. 1(b) or Fig. 2(b))) from the antenna 101 to the base station 200.

[0058] [Configuration of the base station] Fig. 6 is a block diagram showing the configuration of the base station 200 according to the present embodiment.

[0059] In Fig. 6, the base station 200 includes a control information generation unit 201, an encoding / modulation unit 202, a wireless transmission unit 203, an antenna 204, a wireless reception unit 205, a Preamble detection unit 206, a RACH type determination unit 207, a rank determination unit 208, a channel estimation unit 209, and a Data demodulation / decoding unit 210.

[0060] The control information generation unit 201 generates, for example, control information used by the terminal 100 for random access transmission, and outputs the generated control information to the encoding / modulation unit 202. The control information may include, for example, upper layer signaling (for example, RACH-Configuration (RACH-ConfigCommon, RACH-ConfigDedicated, etc.) in NR), and downlink control information (for example, DCI format1_0 in NR) when triggering CFRA.

[0061] In addition, the downlink control information may include, for example, the rank used for the Data part of msg A of the two-step random access, the number of antenna ports of the reference signal, the transmission diversity method, the precoding method, the preamble number in the Preamble part, or the allocated resources of the Preamble part.

[0062] Note that not all control information needs to be notified to the terminal 100 simultaneously. For example, some control information may be notified to the terminal 100 as cell common information, or as semi-static notification information, dynamic notification information (e.g., DCI, etc.). Also, some control information may be defined in the specification as system common information and may not need to be notified from the base station 200 to the terminal 100.

[0063] The encoding / modulation unit 202 modulates and encodes the control information input from the control information generation unit 201, and outputs the modulated signal to the wireless transmission unit 203.

[0064] The wireless transmission unit 203 performs transmission processing such as D / A conversion, up-conversion, and amplification on the signal input from the encoding / modulation unit 202, and transmits the wireless signal obtained by the transmission processing from the antenna 204 to the terminal 100.

[0065] The wireless reception unit 205 performs reception processing such as down-conversion and A / D conversion on the PRACH signal (e.g., msg A) from the terminal 100 received via the antenna 204 in the PRACH transmission resources available within the cell of the base station 200. The wireless reception unit 205 outputs the signal obtained by the reception processing to the Preamble detection unit 206, the channel estimation unit 209, and the Data demodulation / decode unit 210.

[0066] The Preamble detection unit 206 generates a replica signal for detecting the Preamble part signal using the sequence number and CS number corresponding to each Preamble number in the Preamble number group available within the cell of the base station 200. The Preamble detection unit 206 performs correlation processing between the generated replica signal and the signal (e.g., msg A) input from the wireless reception unit 205 to detect the PRACH preamble and perform timing estimation. The Preamble detection unit 206 outputs the detected Preamble number to the RACH type determination unit 207 and the channel estimation unit 209, for example.

[0067] Note that the correlation process in the Preamble detection unit 206 may be a process of calculating a delay profile used in timing estimation by performing correlation processing in the time domain, or a process of calculating a delay profile by performing correlation processing (division processing) in the frequency domain and then performing IFFT (Inverse Fast Fourier Transform).

[0068] The RACH type determination unit 207 determines the RACH type of the PRACH signal (random access signal) received from the terminal 100 based on the Preamble number input from the Preamble detection unit 206.

[0069] For example, the RACH type determination unit 207 determines whether the detected Preamble number is the Preamble number for CFRA notified to the terminal 100 by downlink control information. When the Preamble number is the Preamble number for CFRA, the RACH type determination unit 207 determines that the RACH type of the received PRACH signal is "CFRA". On the other hand, when the Preamble number is not the Preamble number for CFRA, the RACH type determination unit 207 determines that the RACH type of the received PRACH signal is "CBRA". The RACH type determination unit 207 outputs RACH type information indicating the determined RACH Type (for example, either CBRA or CFRA) to the rank determination unit 208.

[0070] The rank determination unit 208 determines the rank (or number of layers) of the Data part based on the RACH Type (for example, CBRA or CFRA) indicated by the RACH type information input from the RACH type determination unit 207. The rank determination unit 208 outputs rank information indicating the determined rank to the channel estimation unit 209 and the Data demodulation / decoding unit 210. An example of the rank determination method in the rank determination unit 208 will be described later.

[0071] The channel estimation unit 209 calculates the number of antenna ports based on the rank indicated by the rank information input from the rank determination unit 208. The channel estimation unit 209 performs correlation processing (for example, division processing) in the frequency domain using replica reference signals on the reference signals assigned to the time, frequency, or code resources corresponding to each of the calculated antenna ports, and calculates the channel estimation values for each antenna port. The channel estimation unit 209 outputs the calculated channel estimation values to the Data demodulation and decoding unit 210.

[0072] The Data demodulation and decoding unit 210 performs demodulation and decoding processing on the Data part signal included in the received signal input from the wireless reception unit 205 based on the channel estimation values input from the channel estimation unit 209 and the rank indicated by the rank information input from the rank determination unit 208, and outputs the decoded data (for example, the Data part signal of msg A).

[0073] [Operations of the terminal 100 and the base station 200] An operation example in the terminal 100 and the base station 200 having the above configuration will be described.

[0074] FIG. 7 is a sequence diagram showing an operation example of the terminal 100 (FIG. 5) and the base station 200 (FIG. 6).

[0075] In FIG. 7, the base station 200 notifies (in other words, informs) the terminal 100 of cell information including control information used by the terminal 100 for PRACH transmission (ST101). For example, the cell information may include upper layer signaling including RACH-Configuration (RACH-ConfigCommon, RACH-ConfigDedicated, etc.) in NR.

[0076] When the base station 200 triggers the PRACH transmission of the terminal 100 (for example, in the case of CFRA), it transmits downlink control information (for example, DCI) to the terminal 100 (ST102). When the base station 200 does not trigger the PRACH transmission of the terminal 100 (for example, in the case of CBRA), it does not have to transmit the DCI.

[0077] The terminal 100 determines the RACH type (CBRA or CFRA) based on, for example, the presence or absence of downlink control information (DCI) (ST103). Also, the terminal 100 determines the rank based on the determined RACH type (ST104). In other words, the terminal 100 determines the configuration of the Data part signal (for example, the number of resources of the reference signal) based on the RACH type.

[0078] The terminal 100 generates the preamble part signal of msg A based on the RACH type (ST105), and generates the Data part signal (for example, data signal and reference signal) of msg A based on the determined rank (ST106).

[0079] The terminal 100 transmits a PRACH signal (for example, msg A) including the generated Preamble part signal and Data part signal to the base station 200 (ST107).

[0080] The base station 200 detects the Preamble part signal and identifies the Preamble number used for the PRACH signal (ST108). Also, the base station 200 determines the RACH type (for example, CBRA or CFRA) based on the identified Preamble number (ST109), and determines the rank based on the determined RACH type (ST110).

[0081] Then, the base station 200 performs channel estimation based on the determined rank, and decodes the Data part signal using the channel estimation value (ST111).

[0082] [Rank Determination Method] Next, an example of the method for determining the rank in the rank determination unit 107 of the terminal 100 and the rank determination unit 208 of the base station 200 will be described.

[0083] Hereinafter, as an example, the rank determination methods 1-1 and 1-2 will be described respectively.

[0084] <Determination method 1-1> In determination method 1-1, the terminal 100 and the base station 200 determine the maximum rank of the Data part of msg A according to the RACH Type (for example, CBRA or CFRA) in PRACH transmission.

[0085] For example, when the RACH type in PRACH transmission is CBRA, the terminal 100 and the base station 200 determine the maximum rank of the Data part of msg A to be "1".

[0086] On the other hand, when the RACH type in PRACH transmission is CFRA, the terminal 100 and the base station 200 determine the maximum rank of the Data part of msg A to be "X" (where X is a value of 1 or more).

[0087] When the RACH type is CFRA, for example, the terminal 100 determines the rank to be used for the transmission of the Data part of msg A from among the values of 1 to X. For example, the value of the rank used by the terminal 100 for the transmission of the Data part may be notified by the downlink control information (DCI) for triggering CFRA. Or, the value of the rank used by the terminal 100 for the transmission of the Data part may be the value of the rank applied to the PUSCH transmission immediately before the PRACH transmission.

[0088] Note that the maximum rank X may be notified from the base station 200 to the terminal 100 by quasi-static notification information such as upper layer signaling, may be notified from the base station 200 to the terminal 100 by dynamic control information such as DCI, or may be defined by a specification or the like.

[0089] Thus, when the RACH type is CBRA, the rank of the Data part of msg A is fixed at 1. As described above, in the two-step random access of CBRA, if the base station 200 does not decode the Data part of msg A, it cannot determine from which terminal 100 msg A was transmitted, and cannot instruct all terminals to transmit on multiple antenna ports. In contrast, when the RACH type is CBRA and the rank is fixed at 1, for example, CBRA can be applied to all terminals 100 including terminals 100 that do not support transmission on multiple antenna ports.

[0090] Also, when the RACH type is CFRA, the rank of the Data part of msg A is selected from 1 to X. As described above, for example, in CFRA, the rank of the Data part used by terminal 100 is selected based on the downlink control information or the rank applied to the PUSCH transmission immediately before the PRACH transmission within the range of 1 to X. Thereby, terminal 100 can dynamically change the rank of the Data part. For example, terminal 100 can appropriately set (e.g., increase or decrease) the amount of transmission data in msg A in CFRA by dynamically changing the rank according to the reception quality.

[0091] Also, in determination method 1-1, since the rank in the case of CBRA is fixed at 1, for example, compared with the method in which the ranks of both CBRA and CFRA are respectively instructed from the base station 200 to the terminal 100, the signaling amount of the control information for instructing the rank of CBRA can be reduced.

[0092] Note that in CFRA, a trigger type associated with the data type (or data amount) to be transmitted to terminal 100 may be provided, and the rank may be uniquely determined according to the trigger type.

[0093] <Determination method 1-2> In determination method 1-2, regardless of the PRACH Type, the maximum rank in the Data part of msg A is fixed.

[0094] For example, when the RACH Type in PRACH transmission is either CBRA or CFRA, the terminal 100 and the base station 200 determine the maximum rank of the Data part of msg A to be "1". In other words, when the RACH type is either CBRA or CFRA, the rank of the Data part of msg A is fixed at 1. In this case, the signaling amount for instructing the rank of the Data part of msg A from the base station 200 to the terminal 100 can be reduced. Also, since the rank of the PRACH signal is fixed, the control of PRACH transmission can be simplified.

[0095] As described above, the method for determining the rank according to this embodiment has been explained.

[0096] Thus, in this embodiment, the terminal 100 and the base station 200 control the configuration of the Data part signal based on the RACH type, which is one of the parameters related to the transmission of the PRACH signal. For example, the terminal 100 and the base station 200 determine the number of resources (e.g., rank or number of antenna ports) of the reference signal (DMRS) for demodulating the data signal in the Data part based on the RACH type.

[0097] Thereby, for example, in the two-step random access of NR, the configuration of the reference signal (e.g., DMRS) of the Data part included in msg A and the multi-layer transmission can be appropriately controlled. Therefore, for example, the terminal 100 can efficiently transmit the PRACH signal for the two-step random access according to the RACH type.

[0098] In addition, in this embodiment, as an example, a method for determining the "maximum rank" based on the RACH type has been described. However, in the rank determination method according to this embodiment, instead of the maximum rank, the maximum number of antenna ports, in other words, the number of resources of reference signals orthogonal by time, frequency, or code may be determined. The number of antenna ports is required to be at least the number of ranks. Therefore, the method for determining the maximum number of antenna ports has the same definition as the case of determining the maximum rank.

[0099] Also, even when the rank is 1, there may be a case where a plurality of antenna ports are set. For example, it is a case where transmit diversity (e.g., SFBC, etc.) is applied to the Data part.

[0100] (Embodiment 2) In Embodiment 1, a method for determining the rank of the Data part of msg A according to the RACH type has been described. In contrast, in this embodiment, a method for determining the rank of the Data part according to the "preamble number" or "time and frequency resources of the preamble" of the preamble part of msg A will be described.

[0101] [Configuration of the terminal] FIG. 8 is a block diagram showing the configuration of the terminal 300 according to this embodiment. In FIG. 8, the same components as those in Embodiment 1 (FIG. 5) are denoted by the same reference numerals, and the description thereof is omitted.

[0102] At the terminal 300, the RACH configuration table 301 is a table in which preamble numbers are grouped according to the rank value used for the Data part of msg A. The information included in the RACH configuration table 301 may be notified from the base station 400 to the terminal 300 by, for example, semi-static notification information (e.g., upper layer signaling) or dynamic notification information (e.g., DCI, etc.). Alternatively, the information included in the RACH configuration table 301 may be defined in the specification as system common information and may not be notified from the base station 400 to the terminal 300.

[0103] The information included in the RACH configuration table 301 is output to, for example, the preamble number selection unit 302 and the rank determination unit 304, respectively. An example of the RACH configuration table 301 will be described later.

[0104] The preamble number selection unit 302 selects a preamble number to be used for PRACH transmission. The preamble number selection unit 302 outputs preamble information indicating the selected preamble number to the preamble generation unit 303 and the rank determination unit 304.

[0105] For example, when the RACH type is CBRA, the preamble number selection unit 302 refers to the RACH configuration table 301 and randomly selects one preamble number from among the preamble numbers included in the group (preamble number group) associated with the information regarding the terminal 300. The information regarding the terminal 300 may be, for example, at least one of the rank of the Data part, the path loss between the terminal 300 and the base station 400, and the amount of information (e.g., number of bits) of the Data part, or other information (e.g., information regarding msg A or the Data part).

[0106] On the one hand, when the RACH type is CFRA, the Preamble number selection unit 302 selects the Preamble number notified by the downlink control information input from the demodulation and decoding unit 103.

[0107] An example of the method for selecting the Preamble number in the Preamble number selection unit 302 will be described later.

[0108] The Preamble generation unit 303 uses the sequence number and CS amount corresponding to the Preamble number indicated in the Preamble information input from the Preamble number selection unit 302 to generate a CS-ZC sequence, and performs processing such as precoding on the generated CS-ZC sequence, and outputs the signal obtained by the processing as the Preamble part signal to the Preamble resource allocation unit 106.

[0109] The rank determination unit 304 refers to the RACH setting table 301 to determine (in other words, judge) the rank corresponding to the Preamble number indicated in the Preamble information input from the Preamble number selection unit 302, and outputs the rank information indicating the determined rank to the Data generation unit 108 and the Data resource allocation unit 110. An example of the method for determining the rank in the rank determination unit 304 will be described later.

[0110] [Configuration of the base station] FIG. 9 is a block diagram showing the configuration of the base station 400 according to the present embodiment. In FIG. 9, the same components as those in the first embodiment (FIG. 6) are denoted by the same reference numerals, and the description thereof is omitted.

[0111] In the base station 400, the RACH setting table 401 is a table in which Preamble numbers are grouped according to the rank (rank value) used for the Data part of msg A, similar to the RACH setting table 301 held by the terminal 300. The information included in the RACH setting table 401 is output to, for example, the rank determination unit 402. An example of the RACH setting table 401 will be described later.

[0112] The rank determination unit 402, similar to the rank determination unit 304 of the terminal 300, refers to the RACH setting table 401 and determines (or equivalently, judges) the rank corresponding to the Preamble number input from the Preamble detection unit 206. The rank determination unit 402 outputs rank information indicating the determined rank to the channel estimation unit 209 and the Data demodulation and decoding unit 210. An example of the rank determination method in the rank determination unit 402 will be described later.

[0113] [Operations of Terminal 300 and Base Station 400] An operation example of the terminal 300 and the base station 400 having the above configuration will be described.

[0114] FIG. 10 is a sequence diagram showing an operation example of the terminal 300 (FIG. 8) and the base station 400 (FIG. 9). In FIG. 10, the same operations as those in the first embodiment (for example, refer to FIG. 7) are denoted by the same reference numerals, and the description thereof is omitted.

[0115] In FIG. 10, the terminal 300 randomly selects one Preamble number from a group of Preamble numbers (group) corresponding to information regarding the terminal 300 (an example will be described later) by referring to, for example, the RACH setting table 301 (ST201). Further, the terminal 300 selects the rank corresponding to the selected Preamble number by referring to the RACH setting table 301 (ST202).

[0116] On the other hand, the base station 400 refers to the RACH setting table 401 and determines the rank corresponding to the Preamble number used in the PRACH signal (or equivalently, the detected Preamble number) (ST203).

[0117] [Rank Determination Method] Next, an example of the rank determination method in the terminal 300 and the base station 400 will be described.

[0118] Hereinafter, as an example, the ranking determination methods 2-1, 2-2, and 2-3 will be described respectively.

[0119] <Determination method 2-1> The RACH setting tables 301 and 401 according to the determination method 2-1 are tables that associate, for example, as shown in FIG. 11, the Preamble number of the Preamble part of msg A with the rank applied to the Data part of msg A.

[0120] The Preamble number selection unit 302 of the terminal 300 selects, for example, in the case of CBRA, the rank of the Data part of msg A using at least one of the following information regarding the terminal 300. (1) Reception quality (e.g., path loss) (2) Data amount of the Data part of msg A (e.g., number of bits) (3) UE Capability (e.g., number of transmission antennas) (4) Rank applied to the PUSCH transmission immediately before the PRACH transmission

[0121] Then, the Preamble number selection unit 302 randomly selects one Preamble number from among the Preamble numbers included in the group corresponding to the selected rank, for example, by referring to the RACH setting table 301 shown in FIG. 11.

[0122] For example, when the selected rank is 1, the Preamble number selection unit 302 selects one Preamble number from among the Preamble numbers 0 to 2 included in group A shown in FIG. 11. Similarly, for example, when the selected rank is 2, the Preamble number selection unit 302 selects one Preamble number from among the Preamble numbers 3 and 4 included in group B shown in FIG. 11.

[0123] Also, in the case of CFRA, the Preamble number selection unit 302 selects the Preamble number included in the DCI notified from the base station 400.

[0124] The rank determination unit 304 of the terminal 300 refers to the RACH configuration table 301 and determines (or judges) the rank of the Data part corresponding to the Preamble number selected by the Preamble number selection unit 302. As an example, in FIG. 11, when the Preamble number 3 is selected by the Preamble number selection unit 302, the rank determination unit 304 determines the rank of the Data part of msg A to be 2. The same applies when the Preamble number selected by the Preamble number selection unit 302 is another number.

[0125] Note that in determination method 2-1, when the Preamble number selection unit 302 selects a Preamble number, since the rank of the Data part is selected, the rank determination unit 304 may use the rank selected by the Preamble number selection unit 302 as it is.

[0126] Also, the rank determination unit 402 of the base station 400 refers to the RACH configuration table 401 and determines (or judges) the rank of the Data part corresponding to the Preamble number detected by the Preamble detection unit 206. As an example, in FIG. 11, when the Preamble number 3 is detected by the Preamble detection unit 206, the rank determination unit 402 determines the rank of the Data part of msg A to be 2. The same applies when the Preamble number detected by the Preamble detection unit 206 is another number.

[0127] In this way, in determination method 2-1, the Preamble number of the Preamble part of msg A is associated with the rank applied to the Data part of msg A. Thereby, since the terminal 300 can determine the rank according to the Preamble number, the control information for notifying the rank from the base station 400 to the terminal 300 becomes unnecessary, and the signaling amount can be reduced.

[0128] Also, in determination method 2-1, the base station 400 can recognize the rank of the Data part of msg A selected by the terminal 300 at the time of Preamble detection. In other words, the base station 400 can recognize the rank of the Data part of msg A before decoding the Data part of msg A. Therefore, in determination method 2-1, in addition to CFRA, CBRA can also apply one or more ranks to the Data part of msg A, and the amount of information that can be transmitted in the Data part of msg A can be increased.

[0129] Note that the table shown in FIG. 11 is an example and is not limited to the association between the Preamble numbers and ranks shown in FIG. 11.

[0130] <Determination method 2-2> The RACH setting tables 301 and 401 according to determination method 2-2 are tables that associate, for example, as shown in FIG. 12, the Preamble number of the Preamble part of msg A, the rank applied to the Data part of msg A, and the path loss value measured from the downlink channel.

[0131] The path loss measured from the downlink channel may be measured, for example, using a synchronization signal.

[0132] As shown in FIG. 12, a lower rank is set for a group with a larger path loss.

[0133] Note that the determination criterion for path loss (the criterion for determining whether the path loss is large or small. For example, a threshold value, etc.) may be defined in the specification, for example, or may be notified by static notification information such as upper layer signaling, or dynamic notification information such as DCI.

[0134] In the preamble number selection unit 302, for example, in the case of CBRA, referring to the RACH setting table 301 shown in FIG. 12, one preamble number is randomly selected from among the preamble numbers included in the group corresponding to the path loss value measured from the downlink channel. For example, when the path loss is "large", the preamble number selection unit 302 selects one preamble number from among the preamble numbers 0 to 2 included in group A shown in FIG. 12. Similarly, for example, when the path loss is "small", the preamble number selection unit 302 selects one preamble number from among the preamble numbers 3 and 4 included in group B shown in FIG. 12.

[0135] Also, in the case of CFRA, for example, the preamble number selection unit 302 selects the preamble number included in the DCI notified from the base station 400.

[0136] Note that the operations of the rank determination unit 304 of the terminal 300 and the rank determination unit 402 of the base station 400 are the same as those in determination method 2-1, so the description is omitted.

[0137] In this way, in determination method 2-2, the preamble number of the preamble part of msg A, the rank applied to the data part of msg A, and the path loss are associated with each other. As a result, the terminal 300 can determine the rank according to the path loss, so that the control information for notifying the rank from the base station 400 to the terminal 300 becomes unnecessary, and the signaling amount can be reduced.

[0138] Also, in determination method 2-2, since the terminal 300 can easily select the rank according to the path loss, the implementation of the terminal 300 can be simplified.

[0139] Also, in determination method 2-2, similar to determination method 2-1, since the base station 400 can recognize the rank of the Data part of msg A selected in the terminal 300 at the time of preamble detection, even in CBRA, one or more ranks can be applied to the Data part of msg A, and the amount of information that can be transmitted in the Data part of msg A can be increased.

[0140] Note that in determination method 2-2, the case of associating path loss with rank has been described. However, the parameter associated with the rank is not limited to path loss, and for example, a parameter with a high correlation with the rank (for example, a parameter related to reception quality) may be sufficient.

[0141] Also, the table shown in FIG. 12 is an example and is not limited to the association of the preamble number, rank, and path loss shown in FIG. 12. For example, in FIG. 12, the case of two levels of path loss (large or small) is shown, but the number of levels of path loss may be three or more. In other words, the number of groups corresponding to the path loss may be three or more.

[0142] <Determination method 2-3> The RACH setting tables 301 and 401 according to determination method 2-3 are tables that associate, for example, as shown in FIG. 13, the preamble number of the Preamble part of msg A, the rank applied to the Data part of msg A, and the amount of information (for example, the number of bits) of the Data part of msg A.

[0143] As shown in FIG. 13, a higher rank is set for a group with a larger amount of information in the Data part.

[0144] Note that the determination criterion for the amount of information (the criterion for determining whether the amount of information is large or small. For example, a threshold value, etc.) may be defined in the specification, for example, or may be notified by quasi-static notification information such as upper layer signaling, or dynamic notification information such as DCI.

[0145] In the preamble number selection unit 302, for example, in the case of CBRA, with reference to the RACH setting table 301 shown in FIG. 13, one preamble number is randomly selected from among the preamble numbers included in the group corresponding to the amount of information in the Data part of msg A. For example, when the amount of information is "small", the preamble number selection unit 302 selects one preamble number from among the preamble numbers 0 to 2 included in group A shown in FIG. 13. Similarly, for example, when the amount of information is "large", the preamble number selection unit 302 selects one preamble number from among the preamble numbers 3 and 4 included in group B shown in FIG. 13.

[0146] Also, in the case of CFRA, for example, the preamble number selection unit 302 selects the preamble number included in the DCI notified from the base station 400.

[0147] Note that the operations of the rank determination unit 304 of the terminal 300 and the rank determination unit 402 of the base station 400 are the same as those in determination method 2-1, so the description thereof is omitted.

[0148] In this way, in determination method 2-3, the preamble number in the Preamble part of msg A, the rank applied to the Data part of msg A, and the amount of information in the Data part of msg A are associated with each other. As a result, the terminal 300 can determine the rank according to the amount of information in the Data part, so that the control information for notifying the rank from the base station 400 to the terminal 300 becomes unnecessary, and the signaling amount can be reduced.

[0149] Also, in determination method 2-3, for example, when the amount of information in the Data part of msg A is large, the terminal 300 can transmit the Data part using a high rank, so that the number of symbols in the Data part of msg A can be reduced.

[0150] Also, in determination method 2-3, similar to determination method 2-1, since the base station 400 can recognize the rank of the Data part of msg A selected in the terminal 300 at the time of Preamble detection, even in CBRA, one or more ranks can be applied to the Data part of msg A, and the amount of information that can be transmitted in the Data part of msg A can be increased.

[0151] Also, the table shown in FIG. 13 is an example and is not limited to the association of the Preamble numbers, ranks, and amounts of information shown in FIG. 13. For example, in FIG. 13, the cases of two types of amounts of information (large or small) are shown, but the number of types of amounts of information may be three or more. In other words, the number of groups corresponding to the amount of information may be three or more.

[0152] The method for determining the rank according to the present embodiment has been described above.

[0153] Thus, in the present embodiment, the terminal 300 and the base station 400 control the configuration of the Data part signal based on the Preamble number, which is one of the parameters related to the transmission of the PRACH signal. For example, the terminal 100 and the base station 200 determine the number of resources (e.g., rank or number of antenna ports) of the reference signal (DMRS) for demodulating the data signal in the Data part based on the Preamble number.

[0154] Thereby, for example, in the two-step random access of NR, the configuration of the reference signal (e.g., DMRS) of the Data part included in msg A and the multi-layer transmission can be appropriately controlled. Therefore, for example, the terminal 300 can efficiently transmit the PRACH signal for the two-step random access according to the Preamble number.

[0155] (Variation 1 of Embodiment 2) In this embodiment, as shown in FIG. 14, the Preamble number of the Preamble part of msg A, the rank applied to the Data part of msg A, and the combination of the information amount and path loss of the Data part of msg A may be associated. In FIG. 14, as an example, for the case where the information amount is "large" and the path loss is "small", a group of rank 2 is associated, and for a case different from the above case, a group of rank 1 is associated. By using the RACH setting tables 301 and 401 shown in FIG. 14, the terminal 300 and the base station 400 can select a rank according to the information amount and path loss of the Data part of msg A.

[0156] (Variation 2 of Embodiment 2) In this embodiment, as an example, the case where the RACH setting tables 301 and 401 include values up to rank 2 (for example, FIGS. 11, 12, 13, and 14) has been described. However, the RACH setting tables 301 and 401 may include ranks higher than rank 2. For example, in the RACH setting tables 301 and 401 shown in FIG. 15, three groups associated with ranks 1, 2, and 4 are set.

[0157] (Variation 3 of Embodiment 2) In this embodiment, the RACH setting tables 301 and 401 that associate the Preamble number of the Preamble part of msg A with the rank applied to the Data part of msg A have been described. However, the RACH setting tables 301 and 401 may include the number of antenna ports instead of the rank applied to the Data part of msg A.

[0158] (Variation 4 of Embodiment 2) In CFRA, instead of applying the association between the Preamble number defined in the RACH configuration tables 301 and 401 and the rank of the Data part of msg A, the terminal 300 may overwrite the rank according to the rank notified by the downlink control information (DCI). By applying the rank notified by the DCI, more flexible rank control becomes possible. For example, if there is only one Preamble number corresponding to rank 2 included in the RACH configuration tables 301 and 401, rank 2 cannot be assigned to multiple terminals. In contrast, for example, the terminal 300 can increase the number of terminals that can use rank 2 in CFRA by preferentially applying the rank notified by the DCI.

[0159] (Variation 5 of Embodiment 2) In this embodiment, the RACH configuration tables 301 and 401 that associate the Preamble number of the Preamble part of msg A with the rank applied to the Data part of msg A have been described. However, in the RACH configuration tables 301 and 401, at least one of the time resource and the frequency resource of the PRACH, rather than the Preamble number, may be associated with the rank applied to the Data part.

[0160] In other words, the terminal 100 and the base station 200 may determine the number of DMRS resources (e.g., rank or number of antenna ports) in the Data part based on the resources used for transmitting the PRACH signal (e.g., the Preamble number or the PRACH resources described above).

[0161] For example, in NR, the number of PRACH frequency resources is indicated to the terminal 300 by control information called "prach-FDM", which is upper layer signaling, and can be selected from 1, 2, 4, 8. Also, the resources for transmitting the PRACH are associated with the SSB (Synchronization Signal Block) index, which is the index of the downlink Synchronization signal.

[0162] Also, depending on the set value of the upper layer signaling, one SSB index may be associated with multiple PRACH resources (also called RACH Occasion). In this case, the terminal 300 randomly selects one resource from among the multiple PRACH resources.

[0163] For example, when there are 4 PRACH resources (e.g., #0, 1, 2, 3) and each resource is associated with a rank (e.g., 1, 1, 1, 2), the terminal 300 may select a PRACH resource according to the rank selected and transmit msg A. For example, in the above example, when the terminal 300 selects rank 1, it randomly selects one resource from PRACH resources #0, 1, 2 and transmits msg A.

[0164] In this way, similar to the Preamble number, by associating the time-frequency resources of the PRACH with the rank applied to the Data part, an effect similar to that of this embodiment can be obtained.

[0165] (Embodiment 3) In Embodiment 1 and Embodiment 2, the method of controlling the rank of the Data part of msg A was described. In contrast, in this embodiment, the method of controlling the resources (e.g., the number of symbols or symbol positions) of the reference signal (e.g., DMRS) of msg A will be described.

[0166] When the base station demodulates and decodes the Data part of msg A, channel estimation is performed. As methods of channel estimation, for example, a method using a reference signal arranged in the Data part of msg A and a method using a Preamble arranged in the Preamble part of msg A can be considered.

[0167] The Preamble is transmitted on one antenna port. Therefore, when the Data part is transmitted on multiple antenna ports such as MIMO or transmit diversity (e.g., SFBC, etc.), the base station cannot use the Preamble for channel estimation, so channel estimation using a reference signal is required.

[0168] Thus, for example, whether the Preamble can be used for channel estimation changes depending on the number of antenna ports used for transmitting the Data part. In other words, whether the Preamble can be used for channel estimation changes depending on whether the number of antenna ports used for transmitting the Data part is the same as the number of antenna ports used for transmitting the Preamble part. Or, whether the Preamble can be used for channel estimation changes depending on whether the precoding between the Preamble part and the Data part is the same.

[0169] Therefore, in this embodiment, a method for controlling the configuration of the reference signal resources (e.g., the number of symbols or symbol positions, etc.) will be described according to whether the Preamble can be applied to channel estimation during demodulation and decoding of the Data part.

[0170] [Configuration of the terminal] FIG. 16 is a block diagram showing the configuration of the terminal 500 according to this embodiment. In FIG. 16, the same components as those in Embodiment 1 (FIG. 5) are denoted by the same reference numerals, and the description thereof is omitted.

[0171] In the terminal 500, the Precoding Determination Unit 501 determines the precoding methods for the Preamble part and the Data part of msg A based on the downlink control information input from the Demodulation / Decoding Unit 103. The Precoding Determination Unit 501 outputs precoding information indicating the determined precoding methods for the Preamble part and the Data part to the Preamble Generation Unit 105, the Data Generation Unit 108, and the Reference Signal Generation Unit 109.

[0172] Each of the Preamble generation unit 105, the Data generation unit 108, and the reference signal generation unit 109 controls the precoding process of a signal (e.g., a Preamble, a data signal, or a reference signal) based on the precoding information input from the Precoding determination unit 501.

[0173] Also, the Precoding determination unit 501 outputs information indicating whether the precoding between the Preamble part and the Data part is the same to the reference signal resource allocation control unit 502.

[0174] An example of the method for determining precoding in the Precoding determination unit 501 will be described later.

[0175] The reference signal resource allocation control unit 502 controls the resources of the reference signal (e.g., at least one of the number of symbols and the symbol position) according to whether the precoding between the Preamble part and the Data part is the same as indicated by the information input from the Precoding determination unit 501. The reference signal resource allocation control unit 502 outputs information indicating the determined resources of the reference signal to the Data resource allocation unit 110. The Data resource allocation unit 110 allocates the reference signal to the resources based on the information indicating the resources.

[0176] An example of the method for determining the resources of the reference signal in the reference signal resource allocation control unit 502 will be described later.

[0177] [Configuration of the base station] FIG. 17 is a block diagram showing the configuration of the base station 600 according to the present embodiment. In FIG. 17, the same components as those in Embodiment 1 (FIG. 6) are denoted by the same reference numerals, and the description thereof is omitted.

[0178] In the base station 600, the Precoding determination unit 601 determines whether the precoding between the Preamble part and the Data part of msg A is the same based on the Preamble number input from the Preamble detection unit 206 and the control information (for example, the information used by the terminal 500 for PRACH transmission) input from the control information generation unit 201. The Precoding determination unit 601 outputs the determination result to the reference signal resource allocation control unit 602.

[0179] The reference signal resource allocation control unit 602 controls the resource of the reference signal (for example, at least one of the number of symbols and the symbol position) according to whether the precoding is the same between the Preamble part and the Data part, as indicated by the information input from the Precoding determination unit 601. The reference signal resource allocation control unit 602 outputs the information indicating the determined reference signal resource to the channel estimation unit 209. The channel estimation unit 209 identifies the resource to which the reference signal is allocated based on this information.

[0180] [Operations of Terminal 500 and Base Station 600] An operation example of the terminal 500 and the base station 600 having the above configuration will be described.

[0181] FIG. 18 is a sequence diagram showing an operation example of the terminal 500 (FIG. 16) and the base station 600 (FIG. 17). In FIG. 18, the same reference numerals are given to the operations similar to those in the first embodiment (for example, see FIG. 7), and the description thereof is omitted.

[0182] In FIG. 18, the terminal 500 determines the precoding method for the Preamble part and the Data part of msg A based on, for example, upper layer signaling or downlink control information (DCI), and determines whether the precoding between the Preamble part and the Data part is the same (ST301).

[0183] The terminal 500 determines the resource allocation (e.g., number of symbols or symbol positions) of the reference signal according to whether the precoding between the Preamble part and the Data part is the same (ST302).

[0184] On the other hand, the base station 600 determines whether the precoding between the Preamble part and the Data part is the same based on the detected Preamble number and the information notified to the terminal 500 using the upper layer signaling or the downlink control information (ST303). Then, the base station 600 determines the resource allocation (e.g., number of symbols or symbol positions) of the reference signal based on the determination result (ST304).

[0185] Next, an example of the method for determining (or judging) Precoding and the method for controlling the resource allocation of the reference signal in the terminal 500 and the base station 600 will be described.

[0186] [Method for Determining and Judging Precoding] As described above, the number of antenna ports of the Preamble part is 1.

[0187] Therefore, the Precoding determination unit 501 of the terminal 500 determines whether the precoding between the Preamble part and the Data part is the same according to, for example, the number of antenna ports applied to the transmission of the Data part of msg A. Note that the number of antenna ports may be notified, for example, by upper layer signaling.

[0188] For example, when the number of antenna ports of the Data part is 1, the Precoding determination unit 501 applies the same precoding method (e.g., random precoding or no precoding) to the Preamble part and the Data part. Therefore, the Precoding determination unit 501 determines that the precoding between the Preamble part and the Data part is the same.

[0189] On the other hand, when the number of antenna ports in the Data part is more than 1, the Precoding Determination Unit 501 applies different precoding methods in the Preamble part and the Data part. For example, the Precoding Determination Unit 501 applies random precoding or no precoding to the Preamble part, and applies SVD precoding or the like to the Data part. Therefore, the Precoding Determination Unit 501 determines that the precoding between the Preamble part and the Data part is not the same (in other words, different).

[0190] Similar to the Precoding Determination Unit 501, the Precoding Determination Unit 601 of the base station 600 determines whether the precoding between the Preamble part and the Data part is the same according to the number of antenna ports applied to the transmission of the Data part of the msg A notified to the terminal 500.

[0191] In the case of CFRA, the terminal 500 may determine whether the precoding between the Preamble part and the Data part is the same based on the number of antenna ports notified by downlink control information (for example, DCI) instead of upper layer signaling.

[0192] In this way, the terminal 500 and the base station 600 determine whether the precoding between the Preamble part and the Data part is the same based on the number of antenna ports in the Data part. For example, when the number of antenna ports in the Data part is more than 1, the terminal 500 and the base station 600 determine that the precoding between the Preamble part and the Data part is different. Thereby, the base station 600 can determine whether the Preamble can be applied to channel estimation during demodulation and decoding of the Data part without additional signaling, so that the signaling amount can be reduced.

[0193] [Reference Signal Resource Allocation Control] The reference signal resource allocation control unit 502 of the terminal 500 and the reference signal resource allocation control unit 602 of the base station 600 change the configuration of the reference signal (for example, at least one of the number of symbols and the symbol position) according to whether the precoding between the Preamble part and the Data part is the same or not.

[0194] <Method for determining the number of symbols of the reference signal> For example, the terminal 500 and the base station 600 set the number of symbols of the reference signal when the precoding between the Preamble part and the Data part is the same to be less than the number of symbols of the reference signal when the precoding between the Preamble part and the Data part is different.

[0195] For example, when the precoding between the Preamble part and the Data part is the same, the terminal 500 and the base station 600 set the number of symbols of the reference signal to "X - 1". On the other hand, when the precoding between the Preamble part and the Data part is different, the terminal 500 and the base station 600 set the number of symbols of the reference signal to "X".

[0196] In this way, by changing the number of symbols of the reference signal according to whether the precoding between the Preamble part and the Data part is the same or not, additional signaling for indicating the number of symbols becomes unnecessary, and the signaling amount can be reduced.

[0197] Also, when the precoding between the Preamble part and the Data part is the same, that is, when the base station 600 can use the Preamble part for channel estimation, the throughput can be improved by reducing the number of symbols of the reference signal and increasing the resources allocated to data. Note that when the base station 600 uses the Preamble part for channel estimation, even if the number of symbols of the reference signal is reduced, the performance degradation due to the deterioration of the channel estimation accuracy is small.

[0198] Note that X may be notified from the base station 600 to the terminal 500 by static notification information or dynamic notification information (such as DCI), or may be defined in the specification as system common information and not be notified from the base station 600 to the terminal 500.

[0199] Also, the difference in the number of symbols (e.g., the difference between X - 1 and X) set according to whether the precoding between the Preamble part and the Data part is the same is not limited to 1, and may be 2 or more.

[0200] <Method for Determining Symbol Arrangement of Reference Signal> For example, the terminal 500 and the base station 600 set the symbol position of the reference signal when the precoding between the Preamble part and the Data part is the same after the symbol position of the reference signal when the precoding between the Preamble part and the Data part is different.

[0201] In other words, the symbol position of the reference signal when the precoding between the Preamble part and the Data part is the same is set at a position farther from the symbol position of the Preamble part than the symbol position of the reference signal when the precoding between the Preamble part and the Data part is different.

[0202] FIG. 19A shows an example of the symbol position where a reference signal (e.g., DMRS) is arranged when the precoding between the Preamble part and the Data part is the same. FIG. 19B shows an example of the symbol position where a reference signal is arranged when the precoding between the Preamble part and the Data part is different.

[0203] As shown in FIG. 19A, when the pre-coding between the Preamble part and the Data part is the same, that is, when the Preamble can be used as a channel estimation value during data demodulation at the base station 600, the reference signal of the Data part is arranged at a position away from the symbol position of the Preamble part. Thereby, the time interpolation accuracy of channel estimation at the base station 600 can be improved, and the deterioration of channel estimation accuracy can be suppressed.

[0204] Also, as shown in FIG. 19B, when the pre-coding between the Preamble part and the Data part is different, that is, when the Preamble cannot be used as a channel estimation value during data demodulation at the base station 600, the reference signal of the Data part is arranged, for example, at the symbol position at the head of the data part. Thereby, at the base station 600, the time required for data demodulation can be shortened. Note that the symbol position of the reference signal of the Data part is not limited to the head of the Data part as shown in FIG. 19B.

[0205] Next, as an example, a method of using the arrangement pattern table of the reference signal (DMRS) for PUSCH defined in NR will be described.

[0206] FIG. 20 shows a part of the arrangement pattern (for example, PUSCH mapping type B) of the DMRS of the PUSCH defined in NR.

[0207] In FIG. 20, "Dmrs-AdditionalPosition" is, for example, the number of symbols (two in FIG. 20) of the additional DMRS notified by upper layer signaling. Also, in the PUSCH mapping type B shown in FIG. 20, the symbol position "l0" is 0 (that is, the head symbol of the PUSCH. In other words, the front-loaded position).

[0208] For example, when the pre-coding between the Preamble part and the Data part is different, the symbol position of the reference signal is set to the position of the first symbol of the PUSCH (front-loaded position). For example, for the symbol position of the reference signal, the first half of the symbol position of the reference signal defined as the frame surrounded by the solid line in FIG. 20 (for example, when the number of DMRSs in the Data part is 1), or the frame surrounded by the dotted line (when the number of DMRSs in the Data part is 2) may be applied.

[0209] Also, for example, when the pre-coding between the Preamble part and the Data part is the same, for the symbol position of the reference signal, like the frame surrounded by the dashed line in FIG. 20 (for example, when the number of DMRSs in the Data part is 1) or the frame surrounded by the double-dashed line (when the number of DMRSs in the Data part is 2), the first DMRS symbol (for example, symbol position l0) is skipped, and the positions of the subsequent symbols (in other words, the second half) may be applied.

[0210] The resource allocation control method of the reference signal has been described above.

[0211] Thus, in this embodiment, the terminal 500 and the base station 600 control the configuration (for example, symbol position or number of symbols) of the reference signal in the Data part based on the pre-coding method, which is one of the parameters related to the transmission of the PRACH signal. Thereby, for example, in the two-step random access of NR, the configuration of the reference signal (for example, DMRS) in the Data part included in msg A can be appropriately controlled. Therefore, for example, the terminal 500 can efficiently transmit the PRACH signal for two-step random access according to the pre-coding method.

[0212] (Embodiment 4) In Embodiment 3, a method of controlling the resource of a reference signal (e.g., the number of symbols or the symbol position) according to the precoding (or the number of antenna ports) applied to the Data part of msg A was described. In contrast, in this embodiment, a method of controlling the resource of the reference signal of the Data part according to the resource of the preamble part of msg A (e.g., the preamble number or the time or frequency resource of the preamble) will be described.

[0213] [Configuration of the terminal] FIG. 21 is a block diagram showing the configuration of a terminal 700 according to this embodiment. In FIG. 21, the same components as those in Embodiment 1 (FIG. 5), Embodiment 2 (FIG. 8), or Embodiment 3 (FIG. 16) are denoted by the same reference numerals, and the description thereof is omitted.

[0214] In the terminal 700, the RACH setting table 701 is a table in which preamble numbers are grouped according to whether the precoding is the same between the Preamble part and the Data part of msg A (hereinafter, may be simply referred to as "consistency of precoding"). The information included in the RACH setting table 701 may be notified from the base station 800 (described later) to the terminal 700 by, for example, semi-static notification information (e.g., upper layer signaling) or dynamic notification information (e.g., DCI, etc.). Alternatively, the information included in the RACH setting table 701 may be defined in the specification as system common information and may not be notified from the base station 800 to the terminal 700.

[0215] The information included in the RACH setting table 701 is output to, for example, the preamble number selection unit 702 and the precoding determination unit 703, respectively. An example of the RACH setting table 701 will be described later.

[0216] The Preamble number selection unit 702 selects a Preamble number to be used for PRACH transmission. The Preamble number selection unit 702 outputs Preamble information indicating the selected Preamble number to the Preamble generation unit 303 and the Precoding determination unit 703.

[0217] For example, when the RACH type is CBRA, the Preamble number selection unit 702 refers to the RACH configuration table 701 and randomly selects one Preamble number from among the Preamble numbers included in the group (Preamble number group) associated with the precoding consistency. On the other hand, when the RACH type is CFRA, the Preamble number selection unit 702 selects the Preamble number notified by the downlink control information input from the demodulation and decoding unit 103. An example of the method for selecting the Preamble number in the Preamble number selection unit 702 will be described later.

[0218] The Precoding determination unit 703 refers to the RACH configuration table 701 and determines whether the precoding between the Preamble part and the Data part is the same (precoding consistency) based on the Preamble number indicated in the Preamble information input from the Preamble number selection unit 702. The Precoding determination unit 703 also determines the precoding method to be applied to the Preamble and the Data part.

[0219] The Precoding determination unit 703 outputs the determined precoding method to the Preamble generation unit 303, the Data generation unit 108, and the reference signal generation unit 109. The Precoding determination unit 703 also outputs information indicating whether the precoding between the Preamble part and the Data part is the same to the reference signal resource allocation control unit 502.

[0220] Similar to Embodiment 3, the reference signal resource allocation control unit 502 determines the reference signal resources based on information indicating whether the precoding between the Preamble part and the Data part input from the Precoding determination unit 703 is the same. In this embodiment, the reference signal resource allocation control unit 502 may also determine the reference signal resources using the Preamble number input from the Preamble number selection unit 702 and the information included in the RACH setting table 701.

[0221] [Configuration of Base Station] FIG. 22 is a block diagram showing the configuration of the base station 800 according to this embodiment. In FIG. 22, the same components as those in Embodiment 1 (FIG. 6), Embodiment 2 (FIG. 9), or Embodiment 3 (FIG. 17) are denoted by the same reference numerals, and their descriptions are omitted.

[0222] In the base station 800, the RACH setting table 801 is a table in which Preamble numbers are grouped according to whether the precoding is the same between the Preamble part and the Data part of msg A (in other words, the precoding consistency), similar to the RACH setting table 701 held by the terminal 700. The information included in the RACH setting table 801 is output to, for example, the Precoding determination unit 802. An example of the RACH setting table 801 will be described later.

[0223] The Precoding determination unit 802 refers to the RACH setting table 801 and determines whether the precoding is the same between the Preamble part and the Data part of msg A based on the Preamble number input from the Preamble detection unit 206. The Precoding determination unit 802 outputs the determination result to the reference signal resource allocation control unit 602.

[0224] Similar to Embodiment 3, the reference signal resource allocation control unit 602 determines the resource of the reference signal based on information indicating whether the precoding between the Preamble part and the Data part input from the Precoding determination unit 802 is the same. Note that in this embodiment, the reference signal resource allocation control unit 602 may determine the resource of the reference signal by using the Preamble number input from the Preamble detection unit 206 and the information included in the RACH setting table 801.

[0225] [Operations of the terminal 700 and the base station 800] An operation example of the terminal 700 and the base station 800 having the above configuration will be described.

[0226] FIG. 23 is a sequence diagram showing an operation example of the terminal 700 (FIG. 21) and the base station 800 (FIG. 22). In FIG. 23, the same reference numerals are given to the operations similar to those in Embodiment 1 (for example, refer to FIG. 7), Embodiment 2 (for example, refer to FIG. 10), or Embodiment 3 (for example, refer to FIG. 18), and the description thereof is omitted.

[0227] In FIG. 23, the terminal 700 selects the Preamble number of msg A (ST401). For example, in the case of CBRA, the terminal 700 refers to the RACH setting table 701 and randomly selects one Preamble number from the group of Preamble numbers corresponding to the precoding methods of the Preamble part and the Data part of msg A. Also, in the case of CFRA, the terminal 700 selects the Preamble number notified by the downlink control information (DCI).

[0228] The terminal 700 refers to the RACH setting table 701 and determines whether the precoding determined between the Preamble part and the Data part is the same based on the selected Preamble number (ST402).

[0229] On the other hand, the base station 800 refers to the RACH setting table 801 and determines whether the precoding determined between the Preamble part and the Data part is the same based on the detected Preamble number (ST403).

[0230] Next, an example of a method for determining (or a method for judging) Precoding in the terminal 700 and the base station 800, and a method for controlling resource allocation of a reference signal will be described.

[0231] Next, a configuration example of the RACH setting tables 701 and 801, and an operation example of the terminal 700 and the base station 800 will be described.

[0232] <Operation Example 1> FIG. 24 shows an example of the RACH setting tables 701 and 801 in Operation Example 1. As shown in FIG. 24, the RACH setting tables 701 and 801 are tables that associate the Preamble number of the Preamble part of msg A with whether the precoding between the Preamble part and the Data part of msg A is the same (hereinafter, may also be simply referred to as the precoding consistency).

[0233] The Preamble number selection unit 702 of the terminal 700 determines whether to make the precoding between the Preamble part and the Data part of msg A the same, for example, in the case of CBRA, using at least one of the following information regarding the terminal 700. (1) The number of antenna ports of the Data part (2) The difference between the required quality of the Data part and the required quality of the Preamble part (3) UE Capability (for example, the number of transmission antennas)

[0234] Note that the required quality of the Data part may be determined, for example, from the set MCS. Also, the required quality of the Preamble part may be determined, for example, from the Preamble format. Also, the parameter for determining whether to make the pre-coding between the Preamble part and the Data part of msg A the same is not limited to the above information, and other information may also be used.

[0235] The Preamble number selection unit 702 randomly selects one Preamble number from among the Preamble numbers included in each group according to whether the pre-coding between the Preamble part and the Data part of msg A is the same, for example, with reference to the RACH setting table 701 shown in FIG. 24.

[0236] For example, when the pre-coding between the Preamble part and the Data part of msg A is the same, the Preamble number selection unit 702 selects one Preamble number from among the Preamble numbers 0 and 1 included in group A shown in FIG. 24. Also, for example, when the pre-coding between the Preamble part and the Data part of msg A is different, the Preamble number selection unit 702 selects one Preamble number from among the Preamble numbers 2 to 4 included in group B shown in FIG. 24.

[0237] On the other hand, the Preamble number selection unit 702 selects the Preamble number included in the DCI notified from the base station 800 in the case of CFRA, for example.

[0238] The Precoding determination unit 703 of the terminal 700 refers to the RACH configuration table 701 and determines whether the precoding is the same between the Preamble part and the Data part of msg A based on the Preamble number selected by the Preamble number selection unit 702. As an example, in FIG. 24, when the Preamble number 1 is selected by the Preamble number selection unit 702, the Precoding determination unit 703 determines that the precoding is the same between the Preamble part and the Data part of msg A. The same applies when the Preamble number selected by the Preamble number selection unit 702 is another number.

[0239] In the operation example 1, since it is determined whether the precoding is the same between the Preamble part and the Data part of msg A in the Preamble number selection unit 702, the Precoding determination unit 703 may directly apply the determination result in the Preamble number selection unit 702.

[0240] Also, the Precoding determination unit 802 of the base station 800 refers to the RACH configuration table 801 and determines whether the precoding is the same between the Preamble part and the Data part of msg A based on the Preamble number detected by the Preamble detection unit 206. As an example, in FIG. 24, when the Preamble number 1 is detected by the Preamble detection unit 206, the Precoding determination unit 802 determines that the precoding is the same between the Preamble part and the Data part of msg A. The same applies when the Preamble number detected by the Preamble detection unit 206 is another number.

[0241] In addition, similar to Embodiment 3, the reference signal resource allocation control unit 502 of the terminal 700 and the reference signal resource allocation control unit 602 of the base station 800 control the resource of the reference signal (for example, at least one of the number of symbols and the symbol position) according to whether the precoding between the Preamble part and the Data part is the same.

[0242] In this way, in Operation Example 1, the Preamble number of the Preamble part of msg A is associated with the consistency of the precoding between the Preamble part and the Data part. As a result, control information for notifying information regarding the consistency of precoding becomes unnecessary, and the signaling amount can be reduced.

[0243] Further, the base station 800 can recognize the difference in precoding between the Preamble part and the Data part selected in the terminal 700 (in other words, the consistency of precoding) when detecting the Preamble (for example, the Preamble number). Therefore, also in CBRA, the precoding between the Preamble part and the Data part can be changed for each terminal 700. Thus, according to Operation Example 1, for example, precoding control can be optimized according to the reception quality for each terminal 700 or UE capability, and the reception performance of the Data part can be improved.

[0244] Also, by changing the resource of the reference signal (for example, the number of DMRS symbols and the DMRS symbol position) according to the Preamble number of the Preamble part of msg A and the consistency of the precoding between the Preamble part and the Data part, the same effects as in Embodiment 3 can be obtained.

[0245] Note that the table shown in FIG. 24 is an example and is not limited to the association between the Preamble number and the rank shown in FIG. 24.

[0246] <Operation Example 2> FIG. 25 shows an example of RACH setting tables 701 and 801 in operation example 2. As shown in FIG. 25, the RACH setting tables 701 and 801 are tables that associate the Preamble number of the Preamble part of msg A, the precoding consistency between the Preamble part and the Data part of msg A, and the number of symbols of a reference signal (e.g., DMRS).

[0247] The Preamble number selection unit 702 of the terminal 700 specifies (in other words, narrows down) a group of Preamble numbers, for example, according to whether the precoding between the Preamble part and the Data part is the same or not, similar to operation example 1. For example, in FIG. 25, when the precoding is different between the Preamble part and the Data part, the Preamble number selection unit 702 narrows down to groups C and D.

[0248] Thereafter, the Preamble number selection unit 702 determines the number of symbols of DMRS, for example, using at least one of the following information regarding the terminal 700. (1) The moving speed of the terminal 700 (2) MCS (3) Rank

[0249] For example, when the moving speed of the terminal 700 is high (e.g., when the moving speed is equal to or higher than a threshold), the Preamble number selection unit 702 sets a larger number of symbols of DMRS to increase the number of symbols of the reference signal and improve the time interpolation accuracy. Also, for example, when the MCS of the Data part of msg A is high (e.g., when the MCS is equal to or higher than a threshold), or when the rank of the Data part of msg A is high (e.g., when the rank is equal to or higher than a threshold), the Preamble number selection unit 702 sets a larger number of symbols of DMRS to improve the channel estimation accuracy. Note that the parameters for determining the number of symbols of DMRS are not limited to the moving speed, MCS, and rank, and other parameters may also be used.

[0250] For example, in FIG. 25, when the pre-coding is different between the Preamble part and the Data part and the number of DMRS symbols is large (for example, two), the Preamble number selection unit 702 randomly selects one Preamble number from the Preamble numbers included in group D.

[0251] In this way, in operation example 2, similar to operation example 1, the Preamble number of the Preamble part of msg A is associated with the consistency of the pre-coding between the Preamble part and the Data part. As a result, control information for notifying whether the pre-coding is the same becomes unnecessary, and the signaling amount can be reduced.

[0252] Also, in operation example 2, since the number of symbols of the reference signal can be set according to the moving speed, MCS, or rank of the terminal 700, the reception performance of the msg A Data part can also be improved in CBRA.

[0253] Note that the table shown in FIG. 25 is an example and is not limited to the association between the Preamble numbers shown in FIG. 25, whether the pre-coding between the Preamble part and the Data part is the same, and the number of DMRS symbols. For example, in FIG. 25, the cases of three types of DMRS symbol numbers are shown, but the number of DMRS symbols may be two types or four or more types. Also, the number of groups of Preamble numbers may be five or more.

[0254] Further, for example, as shown in FIG. 26, the RACH configuration tables 701 and 801 may be tables that associate the Preamble number of the Preamble part of msg A, the consistency of the precoding of the Preamble part and the Data part of msg A, the number of symbols of the DMRS, and the moving speed (or MCS or rank) of the terminal 700. Note that the determination criterion for the moving speed (the criterion for determining whether the moving speed is fast or slow. For example, a threshold value) may be defined in the specification, for example, or may be notified by quasi-static notification information such as upper layer signaling, or dynamic notification information such as DCI.

[0255] The operation examples 1 and 2 have been described above.

[0256] As described above, in this embodiment, the terminal 700 and the base station 800 control the configuration (for example, the number of symbols) of the reference signal of the Data part based on the resource (for example, the Preamble number) of the Preamble part, which is one of the parameters related to the transmission of the PRACH signal. Thereby, for example, in the two-step random access of NR, the configuration (for example, the number of symbols of the DMRS) of the reference signal of the Data part included in msg A can be appropriately controlled. Therefore, for example, the terminal 700 can efficiently transmit the PRACH signal for two-step random access according to the resource of the Preamble part.

[0257] The embodiments of the present disclosure have been described above.

[0258] (Other Embodiments) (1) In the above embodiment, the PRACH has been described as an example of the transmission signal. However, the transmission signal is not limited to the PRACH. For example, it may be other signals transmitted from a terminal (corresponding to a transmitting device) to a base station (corresponding to a receiving device), or a transmission signal transmitted from a base station (corresponding to a transmitting device) to a terminal (corresponding to a receiving device).

[0259] (2) Also, the respective embodiments may be applied in combination. For example, by combining Embodiment 1 and Embodiment 2, as shown in FIG. 27, a defined table associating the RACH type, the preamble number, and the rank number of the Data part of msg A may be used. In this case, the maximum rank number may be set to 1 in CBRA, and a value greater than 1 for the maximum rank in CFRA.

[0260] (3) Also, in the above embodiments, DMRS is used as an example of the reference signal, but the reference signal is not limited to DMRS. For example, the reference signal may be SRS (Sounding Reference Signal) or PT-RS (Phase Tracking Reference Signal).

[0261] The above has described other embodiments.

[0262] This disclosure can be implemented in software, hardware, or software in cooperation with hardware. Each functional block used in the description of the above embodiments can be realized, partially or wholly, as an LSI which is an integrated circuit, and each process described in the above embodiments can be controlled, partially or wholly, by one LSI or a combination of LSIs. The LSI may be composed of individual chips, or may be composed of one chip so as to include part or all of the functional blocks. The LSI may have data input and output. Depending on the degree of integration, the LSI may also be referred to as an IC, a system LSI, a super LSI, or an ultra LSI. The technique of integrating into an integrated circuit is not limited to LSI, and may be realized by an application specific circuit, a general-purpose processor, or a dedicated processor. Also, after manufacturing the LSI, an FPGA (Field Programmable Gate Array) which can be programmed, or a reconfigurable processor which can reconfigure the connection and setting of circuit cells inside the LSI may be used. This disclosure may be realized as digital processing or analog processing. Furthermore, if a technique of integrating into an integrated circuit which replaces the LSI appears due to the progress of semiconductor technology or another derived technology, naturally, the integration of functional blocks may be performed using that technology. Application of biotechnology etc. is possible as a possibility.

[0263] This disclosure can be implemented in any type of apparatus, device, system having a communication function (collectively referred to as a communication device). Non-limiting examples of communication devices include telephones (mobile phones, smartphones, etc.), tablets, personal computers (PCs) (laptops, desktops, notebooks, etc.), cameras (digital still / video cameras, etc.), digital players (digital audio / video players, etc.), wearable devices (wearable cameras, smartwatches, tracking devices, etc.), game consoles, digital book readers, telehealth / telemedicine (remote healthcare / medical prescription) devices, vehicles or mobile transportation means with a communication function (automobiles, airplanes, ships, etc.), and combinations of the various devices described above.

[0264] The communication device is not limited to being portable or movable, and includes all kinds of devices, apparatuses, systems that are not portable or are fixed, such as smart home devices (home appliances, lighting devices, smart meters or measuring devices, control panels, etc.), vending machines, and all other "Things" that can exist on the IoT (Internet of Things) network.

[0265] Communication includes data communication by cellular systems, wireless LAN systems, communication satellite systems, etc., as well as data communication by combinations of these.

[0266] In addition, the communication device also includes devices such as controllers and sensors that are connected or coupled to a communication device that executes the communication functions described in the present disclosure. For example, controllers and sensors that generate control signals and data signals used by a communication device that executes the communication function of the communication device are included.

[0267] In addition, the communication device includes infrastructure facilities, such as base stations, access points, and all other devices, apparatuses, systems that communicate with or control the above-mentioned various non-limited devices.

[0268] The transmission device according to an embodiment of the present disclosure includes a transmission circuit that transmits a random access signal including at least a data part, and a control circuit that controls the configuration of the data part based on parameters related to the transmission of the random access signal.

[0269] In the transmission device according to an embodiment of the present disclosure, the control circuit controls a resource of a reference signal for demodulating a signal of the data part based on the type of random access procedure.

[0270] In a transmission device according to an embodiment of the present disclosure, the control circuit controls a resource of a reference signal for demodulating a signal of the data part based on a resource used for transmitting the random access signal.

[0271] In a transmission device according to an embodiment of the present disclosure, the control circuit controls a resource of a reference signal for demodulating a signal of the data part based on whether a first precoding of a preamble part included in the random access signal is the same as a second precoding of the data part.

[0272] In a transmission device according to an embodiment of the present disclosure, the resource of the reference signal is the number of symbols of the reference signal, and the number of symbols when the first precoding and the second precoding are the same is smaller than the number of symbols when the first precoding and the second precoding are different.

[0273] In a transmission device according to an embodiment of the present disclosure, the resource of the reference signal is the symbol position of the reference signal, and the symbol position when the first precoding and the second precoding are the same is later than the symbol position when the first precoding and the second precoding are different.

[0274] In a transmission device according to an embodiment of the present disclosure, when the number of antenna ports used for a signal of the data part is more than 1, the first precoding and the second precoding are different.

[0275] In a transmission device according to an embodiment of the present disclosure, the control circuit determines whether the first precoding and the second precoding are the same based on a resource of the preamble part.

[0276] A receiving apparatus according to an embodiment of the present disclosure includes a receiving circuit that receives a random access signal including at least a data part, and a control circuit that controls the configuration of the data part based on parameters related to the transmission of the random access signal.

[0277] A transmission method according to an embodiment of the present disclosure transmits a random access signal including at least a data part, and controls the configuration of the data part based on parameters related to the transmission of the random access signal.

[0278] A receiving method according to an embodiment of the present disclosure receives a random access signal including at least a data part, and controls the configuration of the data part based on parameters related to the transmission of the random access signal.

[0279] The disclosures of the specification, drawings, and abstract included in Japanese Patent Application No. 2018-247260 filed on December 28, 2018 are all incorporated herein by reference.

Industrial Applicability

[0280] An embodiment of the present disclosure is useful for a mobile communication system.

Explanation of Signs

[0281] 100, 300, 500, 700 Terminal 101, 204 Antenna 102, 205 Radio Receiving Unit 103 Demodulation and Decoding Unit 104, 207 RACH type Determination Unit 105, 303 Preamble Generation Unit 106 Preamble Resource Allocation Unit 107, 208, 304, 402 rank Determination Unit 108 Data Generation Unit 109 Reference Signal Generation Unit 110 Data Resource Allocation Unit 111, 203 Radio Transmission Unit 200, 400, 600, 800 Base Station 201 Control Information Generation Unit 202 Encoding / Modulation Unit 206 Preamble Detection Unit 209 Channel Estimation Unit 210 Data Demodulation / Decoding Unit 301, 401, 701, 801 RACH Setting Table 302, 702 Preamble Number Selection Unit 501, 703 Precoding Decision Unit 502, 602 Reference Signal Resource Allocation Control Unit 601, 802 Precoding Judgment Unit

Claims

A network system including a communication device and a terminal, wherein the communication device transmits resource information regarding a preamble part and a data part in Message A to the terminal, and the resource information includes a first preamble number included in group A used when the first antenna port number is applied to the data part by the terminal, and a second preamble number included in group B used when the second antenna port number is applied to the data part by the terminal, and includes a transmission unit; the terminal includes a reception unit that receives the resource information; and a transmission unit that, based on the resource information, randomly selects one preamble number from the group corresponding to the antenna port number applied to the data part of Message A among group A and group B, applies the one preamble number to the preamble part of Message A, and transmits Message A to the communication device. A network system.

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