Terminal, base station, and wireless communication system

Abstract

This terminal has a reception unit, a control unit, and a transmission unit. The reception unit receives a first signal transmitted from a base station. The control unit determines, according to the received first signal or first information included in the received first signal, a spreading code to be used for a second signal transmitted from the terminal to the base station. In addition, the control unit performs control to encode the second signal by using the spreading code determined according to the first signal and the first information included in the first signal. The transmission unit transmits, to the base station, the second signal encoded by using the spreading code.

Description

Terminal, base station, and wireless communication system

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

[0002] In today's networks, traffic from mobile devices (smartphones and feature phones) accounts for the majority of network resources, and traffic from mobile devices is expected to continue to grow.

[0003] In addition to traffic used by mobile terminals, for example, IoT (Internet of Things) services (for example, monitoring systems for transportation systems, smart meters, devices, etc.) are being deployed. Therefore, networks are required to support services with diverse requirements. In order to support such diverse services, for example, in communication standards for fifth-generation mobile communications (5G or NR (New Radio)) (for example, Non-Patent Documents 1 to 14), standards are being developed assuming support for many use cases classified as eMBB (Enhanced Mobile Broadband), Massive MTC (Machine Type Communications), and URLLC (Ultra-Reliable and Low Latency Communications).

[0004] In 3GPP (3rd Generation Partnership Project (registered trademark)), a technology is being considered that enables communication, for example, in mountainous areas or on the sea, by applying NR to non-terrestrial networks (NTNs) (for example, Non-Patent Document 15).

[0005] Also, in 3GPP, for example, in uplink communications of NTN, application of orthogonal cover codes (OCC) as spreading codes and code multiplexing is being considered (Non-Patent Document 16). Note that when a sequence length N is given, an orthogonal code is composed of N orthogonal sequences.

[0006] 3GPP TS 37.324 V18.0.03GPP TS 37.340 V18.2.03GPP TS 38.201 V18.0.03GPP TS 38.202 V18.3.03GPP TS 38.211 V18.3.03GPP TS 38.212 V18.3.03GPP TS 38.213 V18.3.03GPP TS 38.214 V18.3.03GPP TS 38.215 V18.3.03GPP TS 38.300 V18.2.03GPP TS 38.321 V18.2.03GPP TS 38.322 V18.1.03GPP TS 38.323 V18.2.03GPP TS 38.331 V18.2.03GPP TR 38.821 V16.2.03GPP RP-241667

[0007] For example, when a first signal transmitted by a first terminal and a second signal transmitted by a second terminal are code-multiplexed using a spreading code, a method for controlling the first terminal and the second terminal is required so that the base station can separate the first signal from the second signal. However, discussions on control when OCC is applied as a spreading code to the uplink communication of terminals have only just begun, and the details have not yet been decided.

[0008] The disclosed technology has been made in consideration of the above, and provides a method for controlling spreading codes on the transmitting side in order to separate multiple signals that have been code-multiplexed using spreading codes on the receiving side.

[0009] In one aspect, a terminal is provided that has a receiving unit that receives a first signal from a base station, a control unit that determines a spreading code to be used for a second signal depending on the first signal or first information contained in the first signal and encodes the second signal using the determined spreading code, and a transmitting unit that transmits the second signal encoded using the spreading code to the base station.

[0010] In one aspect, a base station is provided that has a transmitting unit that transmits a first signal to a terminal, a receiving unit that receives one or more signals including the first signal or a second signal encoded with a spreading code corresponding to first information included in the first signal, and a control unit that performs processing to obtain the second signal using the spreading code.

[0011] At the receiving end, it is possible to separate a signal coded using a spreading code from multiple code-multiplexed signals.

[0012] FIG. 1 is a diagram showing an example of a wireless communication system according to a first embodiment. FIG. 2 is a diagram showing an example of a functional configuration block diagram of a base station in the wireless communication system according to the first embodiment. FIG. 3 is a diagram showing an example of a functional configuration block diagram of a terminal in the wireless communication system according to the first embodiment. FIG. 4 is a diagram showing an example of a sequence in the wireless communication system according to the first embodiment. FIG. 5 is a diagram showing an example of a sequence used in an orthogonal code. FIG. 6 is a diagram showing an example of a method for extracting one signal from multiple code-multiplexed signals. FIG. 7 is a diagram showing an example of a sequence in a wireless communication system according to a second embodiment. FIG. 8 is a diagram showing an example of a functional configuration block diagram of a base station according to a fifth embodiment. FIG. 9 is a diagram showing an example of the hardware configuration of a base station. FIG. 10 is a diagram showing an example of the hardware configuration of a terminal.

[0013] The present embodiment will be described in detail below with reference to the drawings. The problems and examples in this specification are merely examples and do not limit the scope of the rights of the present application. In particular, even if the expressions used are different, the technology of the present application can be applied as long as they are technically equivalent, and do not limit the scope of the rights. Furthermore, each embodiment can be combined as appropriate within the scope of not causing any contradiction in the processing content.

[0014] Furthermore, the terms used and technical contents described in this specification may be those described in specifications and contributions as standards related to communications, such as 3GPP, as appropriate. Examples of such specifications include those described in Non-Patent Documents 1 to 14.

[0015] Hereinafter, embodiments of a base station, a terminal, and a wireless communication system disclosed in the present application will be described in detail with reference to the accompanying drawings. Note that the disclosed technology is not limited to the following embodiments. First Embodiment

[0016] 1 is a diagram showing an example of a wireless communication system 1 according to the first embodiment. The wireless communication system 1 includes a base station 100, and terminals 200A and 200B. The base station 100 forms a cell C10. The terminals 200A and 200B are present in the cell C10. When there is no need to distinguish between the terminals 200A and 200B, they will be simply referred to as terminals 200.

[0017] Note that the base station 100 may be, for example, a small wireless base station (including a micro wireless base station, a femto wireless base station, etc.) such as a macro wireless base station or a pico wireless base station, or may be a wireless base station of various scales, and may be referred to as a wireless communication device, a communication device, a transmitting device, etc. Furthermore, the terminal 200 may be a wireless terminal such as various devices having a wireless communication function, such as a mobile phone, a smartphone, a PDA (Personal Digital Assistant), a personal computer, a vehicle, an airplane, a drone, etc., or a device (sensor device, etc.) mounted on a robot, AV equipment, home appliances, office equipment, vending machines, other household equipment, industrial equipment, etc., and may be referred to as a wireless communication device, a communication device, a receiving device, a mobile station, etc.

[0018] The base station 100 is connected to a network device (a higher-level device or another base station) not shown in the figure via a wired connection. Note that the base station 100 may be connected to the network device wirelessly instead of via a wired connection.

[0019] The base station 100 may have a wireless communication function with the terminal 200 and a digital signal processing and control function separated into separate devices. In this case, the device having the wireless communication function may be called an RRH (Remote Radio Head), and the device having the digital signal processing and control function may be called a BBU (Base Band Unit). The RRHs may be installed extending from the BBU, and they may be connected by a wired connection such as optical fiber. Alternatively, they may be connected wirelessly. Instead of the aforementioned RRH and BBU, the base station 100 may be separated into, for example, a Central Unit (CU), a Distributed Unit (DU), and a Radio Unit (RU). The DU may include, for example, a MAC (Media Access Control) layer function. The DU may also include, for example, a function of an RLC (Radio Link Control) layer. The RU includes at least an RF wireless circuit. The DU and RU may also be integrated into one unit.

[0020] On the other hand, the terminal 200 communicates with the base station 100 via wireless communication.

[0021] Next, the base station 100 will be described. Fig. 2 is a diagram showing an example of a functional configuration diagram of the base station 100. The base station 100 has a wireless communication unit 110, a control unit 120, a storage unit 130, and a communication unit 140.

[0022] The wireless communication unit 110 is composed of a transmitting unit 111 and a receiving unit 112, and performs wireless communication with the terminal 200. Specifically, the transmitting unit 111 transmits to the terminal 200 downlink signals such as measurement signals (e.g., SSB, reference signals) that the terminal is to measure, random access procedure signals, RRC layer signals, downlink data signals, and downlink control signals.

[0023] The receiving unit 112 can receive uplink signals, such as random access procedure signals, RRC layer signals, uplink data signals, and uplink control signals, transmitted from the terminal 200. The receiving unit 112 receives signals to which spreading codes have been applied from the terminal 200.

[0024] The control unit 120 controls the base station 100. Specifically, the control unit 120 can control the establishment of an RRC connection with the terminal 200, signal processing of signals received by the receiving unit 112, creation of transmission blocks (TBs), mapping of the transmission blocks to radio resources, and the like. The control unit 120 can also control the demultiplexing of signals code-multiplexed using spreading codes. For example, the control unit 120 multiplies a signal transmitted by the terminal 200A and a signal transmitted by the terminal 200B, which are received on a specific resource, by a sequence of spreading codes corresponding to the signal transmitted by the terminal 200A, thereby performing a process of excluding the signal from the terminal 200B. The control unit 120 also multiplies a signal transmitted by the terminal 200A and a signal transmitted by the terminal 200B, which are received on a specific resource, by a sequence of spreading codes corresponding to the signal transmitted by the terminal 200B, thereby performing a process of excluding the signal from the terminal 200A.

[0025] The storage unit 130 can store, for example, downstream data signals.

[0026] The communication unit 140 connects to a network device (e.g., a higher-level device, another base station) via a wired or wireless connection to communicate with the network device. Data signals received by the communication unit 140 and directed to the terminal 200 can be stored in the storage unit 130. The wireless communication unit 110 and the communication unit 140 may be collectively referred to as the communication unit.

[0027] Next, the terminal 200 will be described. Fig. 3 is a diagram showing an example of a functional configuration diagram of the terminal 200. As shown in Fig. 3, the terminal 200 includes a communication unit 210, a control unit 220, and a storage unit 230. These components are connected to each other so as to enable unidirectional or bidirectional input and output of signals and data. The communication unit 210 can be described as being divided into a transmission unit 211 and a reception unit 212.

[0028] The transmitter 211 transmits data signals and control signals by wireless communication via an antenna. Note that the antenna may be common for both transmission and reception. The transmitter 211 transmits uplink signals such as random access procedure signals, RRC layer signals, uplink data signals, and uplink control signals, for example.

[0029] The receiver 212 receives downlink signals, such as a random access procedure signal, a downlink data signal, and a downlink control signal, transmitted from the base station 100. The received signals may also include reference signals used for channel estimation and demodulation. The receiver 212 can also receive measurement signals transmitted from the base station 100 and measure the signals.

[0030] The control unit 220 controls the terminal 200. Specifically, the control unit 220 can control the establishment of an RRC connection with the base station 100, signal processing of signals received by the receiving unit 212, creation of transmission blocks (TBs), mapping of the transmission blocks to radio resources, etc. The control unit 220 can also control the measurement of measurement signals in the receiving unit 212. The control unit 220 can control uplink signals using spreading codes.

[0031] The storage unit 230 can store, for example, uplink data signals, and can also store configuration information (or setting information) related to wireless communication transmitted from the base station 100.

[0032] Next, a processing flow of the wireless communication system 1 in the first embodiment will be described with reference to Fig. 4. Fig. 4 is an example of a sequence diagram of the wireless communication system 1.

[0033] The base station 100 transmits a first signal to the terminal 200 (step S10). The first signal may include, for example, first information related to a spreading code. The first signal may be, for example, an RRC layer signal or a physical layer signal.

[0034] The terminal 200 receives a first signal from the base station 100 (step S10). Then, the terminal 200 performs a first process (step S20). Note that the first process may be performed at any timing as long as it is before the terminal 200 transmits a second signal.

[0035] The first processing includes a process of determining at least one parameter of the spreading code in accordance with the first signal or first information included in the first signal, and a process of encoding the second signal using the spreading code, which is transmitted by the terminal 200. The parameter of the spreading code is, for example, a sequence number of the spreading code and a sequence length of the spreading code.

[0036] In the first process, the terminal 200 transmits a second signal encoded using a spreading code to the base station 100 (step S30). The base station 100 receives the second signal encoded using the spreading code (step S30).

[0037] The base station 100 performs a second process on the received second signal (step S40). Note that the second process may involve, for example, multiplying the received signal by a sequence of spreading codes corresponding to the second signal, thereby excluding signals other than the second signal and acquiring the second signal.

[0038] For example, when base station 100 receives a signal in which multiple signals including second signal A transmitted by terminal 200A and second signal B transmitted by terminal 200B are code-multiplexed, base station 100 multiplies the received multiple signals by a spreading code corresponding to second signal A to extract second signal A transmitted by terminal 200A, and multiplies the received multiple signals by a spreading code corresponding to second signal B to extract second signal B transmitted by terminal 200B. Details of the method for extracting one signal from multiple signals will be described later.

[0039] Here, spreading codes will be explained. Examples of spreading codes include orthogonal cover codes (OCC). When a sequence length N (N is an integer) is given, the orthogonal code is composed of N orthogonal sequences.

[0040] Sequences used in orthogonal codes will be described with reference to Fig. 5. Fig. 5 is a diagram showing an example of a sequence used in orthogonal codes. Fig. 5(A) shows an example of a Walsh sequence, and Fig. 5(B) shows an example of a DFT (Discrete Fourier Transform) sequence. The Walsh sequence has a sequence length of 2. Ｎand is composed of two values, "+1" and "-1." The DFT sequence has a sequence length greater than 1 and utilizes the orthogonality of DFT.

[0041] The Walsh sequence shown in FIG. 5A shows a case where the sequence length is 4. When terminal 200 repeatedly transmits a signal four times using the Walsh sequence shown in FIG. 5A, the value by which each signal is multiplied is determined by the sequence number. For example, when terminal 200 uses sequence number 1, all signals are multiplied by "+1". Also, when terminal 200 uses sequence number 2, the first signal transmitted and the third signal transmitted are multiplied by "+1", and the second signal transmitted and the fourth signal transmitted are multiplied by "-1". Note that the multiplication process in terminal 200 is performed, for example, in the first process.

[0042] The DFT sequence shown in Fig. 5(B) shows the case where the sequence length is 4. When terminal 200 transmits a signal by repeating it four times using the DFT sequence shown in Fig. 5(B), the value by which each signal is multiplied is determined by the sequence number.

[0043] Here, a method for extracting one signal from multiple code-multiplexed signals in base station 100 will be described with reference to Fig. 6. Fig. 6 is a diagram showing an example of a method for extracting one signal from multiple code-multiplexed signals. It is assumed that the Walsh sequence shown in Fig. 5(A) is used as the spreading code. In addition, the description will be given using an example in which terminal 200A transmits signal A four times in repetition, and terminal 200B transmits signal B four times in repetition.

[0044] Base station 100 receives signal group C including signals A-1, A-2, A-3, and A-4 transmitted from terminal 200A, and signals B-1, B-2, B-3, and B-4 transmitted from terminal 200B. Note that signals A-1, A-2, A-3, and A-4 will be simply referred to as signal A when they are not distinguished. Furthermore, signals B-1, B-2, B-3, and B-4 will be simply referred to as signal B when they are not distinguished. Furthermore, it is assumed that terminal 200A uses a sequence corresponding to sequence number 1. Furthermore, it is assumed that terminal 200B uses a sequence corresponding to sequence number 2.

[0045] When base station 100 multiplies signal group C by the sequence with sequence number 1, signals B-1 and B-3 and signals B-2 and B-4 have different plus and minus signs. Here, if signals B-1 to B-4 are the same signal, they cancel each other out, making it possible to remove the component of signal B.

[0046] Furthermore, when base station 100 multiplies signal group C by the sequence with sequence number 2, signals A-1 and A-3 and signals A-2 and A-4 have different plus and minus signs. Here, if signals B-1 to B-4 are the same signal, they cancel each other out, making it possible to remove the component of signal A.

[0047] Although the case of sequence numbers 1 and 2 has been described, the same applies when sequence numbers 3 and 4 are used.

[0048] In this way, the base station 100 can extract the signal transmitted by the terminal 200 from the multiple code-multiplexed signals by recognizing the spreading code used by the terminal 200. Therefore, the base station 100 uses the first signal to allow the base station 100 and the terminal 200 to share the spreading code used by the terminal 200.

[0049] As described above, in the first embodiment, the terminal 200 determines a spreading code for code multiplexing in accordance with the first signal transmitted by the base station 100, and controls the second signal using the determined spreading code. The base station 100 also transmits the first signal, receives one or more signals including a second signal encoded with the spreading code, and acquires the second signal from the received one or more signals using the spreading code determined in accordance with the first signal. In this manner, the base station 100 and the terminal 200 can share spreading codes, thereby enabling signals encoded using spreading codes to be separated from multiple code-multiplexed signals. Embodiment 2

[0050] In the first embodiment, an example has been described in which a spreading code for code multiplexing is determined in accordance with a first signal transmitted by the base station 100, and the determined spreading code is used to control the second signal. In the second embodiment, a specific example of the first embodiment will be described. Note that in the second embodiment, the wireless communication system, the base station, and the terminal are the same as those in the first embodiment, and therefore description thereof will be omitted.

[0051] The flow of processing in the second embodiment will be described with reference to Fig. 7. Fig. 7 is a diagram showing an example of a sequence of a communication system in the second embodiment. In Fig. 7, the same processing as in Fig. 4 is assigned the same step number.

[0052] The base station 100 transmits an RRC layer signal (step S50). The terminal 200 receives the RRC layer signal (step S50). The RRC layer signal includes, for example, parameters used for communication. The RRC layer signal is, for example, an RRC setup message, an RRC reconfiguration message, or an RRC re-establishment message.

[0053] The terminal 200 transmits a response signal corresponding to the signal of the RRC layer (step S60). The base station 100 receives the response signal (step S60). The response signal is, for example, an RRC setup complete message, an RRC reconfiguration complete message, or an RRC re-establishment complete message.

[0054] The base station 100 transmits a control signal including downlink control information (step S70). The terminal 200 receives the control signal including downlink control information (step S70). Note that, for example, if uplink resources are configured by the RRC layer signal of step S50 or an RRC layer signal different from the RRC layer signal transmitted in step S50, the processing of step S70 may be skipped. Note that the uplink resources configured by the RRC layer signal may be referred to as a Configured Grant (CG).

[0055] The terminal 200 transmits the second signal using the information indicating the uplink resource included in the control signal received in step S70 or the information on the uplink resource indicated by the CG (step S30).

[0056] In the second embodiment, base station 100 notifies terminal 200 of a sequence number used for a spreading code. Three examples of a method for notifying a sequence number will be described below. The first example described below is an example in which a sequence number is notified using control information included in a control signal. The second example is an example in which a sequence number is notified using a signal of the RRC layer. The third example is an example in which a sequence number is notified using a correspondence relationship between a sequence number and a resource for receiving a control signal.

[0057] (First Example) In the first example, information indicating a sequence number is included in the control information included in the control signal transmitted in step S70. For example, the information indicating the sequence number indicates sequence number 1.

[0058] A specific example of information indicating sequence numbers will be described. For example, a correspondence relationship between sequence numbers is set for each antenna port. For example, sequence number 1 is set to correspond to the first antenna port, and sequence number 2 is set to correspond to the second antenna port 2. The correspondence relationship between sequence numbers and antenna ports may be set in advance as a standard, or may be set in the RRC layer signal transmitted in step S50.

[0059] Then, the base station 100 includes information indicating the antenna port in the control information. For example, when the first antenna port is indicated, the terminal 200 uses the sequence with sequence number 1 corresponding to the first antenna port as a spreading code in the first processing. Note that the information indicating the antenna port is an example of information indicating a sequence number. Note that in the first example, the control signal transmitted in step S70 corresponds to the first signal transmitted in step S10 of FIG. 4.

[0060] In the second process, base station 200 determines the sequence number used when terminal 200 transmits the second signal based on the information indicating the antenna port transmitted to terminal 200.

[0061] (Second Example) In a second example, information regarding a sequence number is included in the RRC layer signal transmitted in step S50. The information regarding the sequence number is, for example, information indicating the correspondence between antenna ports and sequences, or information indicating the correspondence between information regarding the time resource of the uplink signal and sequences or sequence numbers. In the second example, the control signal transmitted in step S50 corresponds to the first signal transmitted in step S10 of FIG.

[0062] The information indicating the correspondence between the antenna port and the sequence is, for example, a signal that associates the DMRS-Port with the sequence number. The DMRS-Port is set for each terminal 200 for channel measurement.

[0063] For example, the first DMRS-Port is associated with the sequence of sequence number 1, and the second DMRS-Port is associated with the sequence of sequence number 2. When terminal 200 uses the first DMRS-Port, terminal 200 uses the sequence of sequence number 1 as a spreading code.

[0064] In the first process, the terminal 200 determines a spreading code based on the set DMRS-Port.

[0065] In the second process, the base station 200 determines the sequence number used when the terminal 200 transmits the second signal based on the DMRS-Port set in the terminal 200.

[0066] Furthermore, the information indicating the correspondence between information regarding the time resources of uplink signals and sequences or sequence numbers, for example, corresponds to a sequence number for each PUSCH-TimeDomainResourceAllocationList (hereinafter referred to as PUSCHList). For example, multiple PUSCHLists can be set in PUSCHConfig, and a sequence number is specified for each PUSCHList. Note that the same sequence number may be set for two or more PUSCHLists within multiple PUSCHLists. For example, sequence number 1 may be set for the first PUSCHList and the second PUSCHList, and sequence number 2 may be set for the third PUSCHList.

[0067] In the first process, terminal 200 determines a spreading code based on the resource for transmitting the second signal and on the PUSCHList corresponding to the resource used for transmission.

[0068] In the second process, base station 200 determines the sequence number used when terminal 200 transmits the second signal, according to the PUSCHList corresponding to the resource used by terminal 200 for transmission.

[0069] (Third Example) In the third example, a resource to which the control signal to be transmitted in step S70 is mapped is associated with a sequence number, and the sequence number is notified from base station 100 to terminal 200. Note that the correspondence between the sequence number and the resource to which the control signal is mapped may be set in advance as a standard, or may be set in the RRC layer signal transmitted in step S50. Note that in the first example, the control signal transmitted in step S70 corresponds to the first signal transmitted in step S10 of FIG. 4.

[0070] Base station 100 transmits a control signal using one or more control channel elements (CCEs) within an area for transmitting the control signal. Terminal 200 detects multiple CCEs to which the control signal is mapped by blind decoding a set search space. Note that the search space is a part of the area for transmitting the control signal.

[0071] Here, in the first process, terminal 200 determines a sequence number using the CCE index of one or more CCEs to which the control signal is mapped. For example, terminal 200 determines a sequence number using the first CCE index (e.g., the index with the lowest numerical value) of the multiple CCEs to which the control signal is mapped. For example, terminal 200 determines a sequence number using the last CCE index (e.g., the index with the highest numerical value) of the multiple CCEs to which the control signal is mapped.

[0072] In the second process, the base station 200 determines the sequence number used by the terminal 200 when transmitting the second signal, using the CCE index of one or more CCEs to which the control signal transmitted to the terminal 200 is mapped.

[0073] The number of CCEs to which control signals are mapped is determined according to the aggregation level that configures the search space. Therefore, the relationship between CCE indexes and sequence numbers may be different for each aggregation level.

[0074] As described above, in the second embodiment, the terminal 200 determines a sequence corresponding to a sequence number according to a first signal received from the base station 100 as a spreading code for code multiplexing, and controls the second signal using the determined spreading code. The base station 100 also transmits the first signal, receives one or more signals including a second signal encoded with the spreading code, and acquires the second signal from the one or more received signals using the spreading code determined according to the first signal. In this way, the spreading code can be shared between the base station 100 and the terminal 200, and therefore the signal encoded using the spreading code can be separated from the multiple code-multiplexed signals. Embodiment 3

[0075] In the first embodiment, an example has been described in which a spreading code for code multiplexing is determined in accordance with a first signal transmitted by the base station 100, and the determined spreading code is used to control the second signal. In the second embodiment, a specific example of the first embodiment has been described, in which a method for instructing a sequence number from the base station 100 to the terminal 200 has been described. In the third embodiment, another specific example of the first embodiment will be described. Note that in the third embodiment, the wireless communication system 1, the base station 100, and the terminal 200 are the same as those in the first embodiment, and therefore description thereof will be omitted.

[0076] In the third embodiment, a method for determining the sequence length used by the base station 100 and the terminal 200 for the spreading code will be described. Two examples of the method for determining the sequence length will be described below. The first example described below is an example in which the sequence length is notified using a signal in the RRC layer. The second example is an example in which the sequence length is determined from the number of repeated transmissions of a second signal transmitted from the terminal 200 to the base station 100. The processing flow in the third embodiment is the same as that in the second embodiment, and therefore description thereof will be omitted.

[0077] (First Example) The first example is an example in which information regarding sequence length is notified using an RRC layer signal. For example, information regarding the sequence length corresponding to each PUSCH List is included. Note that the sequence length information is, for example, information indicating the length of the sequence length and information regarding the number of repeated transmissions. Note that in the first example, the RRC layer signal transmitted in step S50 corresponds to the first signal transmitted in step S10 of FIG. 4.

[0078] In addition, code multiplexing becomes easier when the sequence length of the spreading code and the number of repeated transmissions are the same, so the base station 100 and the terminal 200 can determine the sequence length from information on the number of repeated transmissions.

[0079] In the first process, terminal 200 determines the sequence length to be used for the second signal from information related to the sequence length.

[0080] In addition, in the second processing, base station 100 determines the sequence number used when terminal 200 transmits the second signal from the information related to the sequence length.

[0081] (Second Example) The second example is an example in which the sequence length is determined from the number of repeated transmissions of a second signal transmitted from terminal 200 to base station 100. In the second example, of the RRC layer signal transmitted in step S50 and the control signal transmitted in step S70, the signal containing information indicating the number of repeated transmissions corresponds to the first signal transmitted in step S10 in FIG.

[0082] Here, the number of repeated transmissions and the sequence length satisfy one of the conditions of the following (Equation 1) and (Equation 2): Note that N in (Equation 1) and (Equation 2) is an integer.

[0083] (Formula 1) Sequence length × N = number of repeated transmissions

[0084] (Equation 2) Number of repeated transmissions≧2 Ｎ

[0085] The condition of (Equation 1) is that an integer multiple of the sequence length satisfies the number of repeated transmissions. The condition of (Equation 2) is the maximum N that satisfies (Equation 2). The sequence length when (Equation 2) is satisfied is 2 Ｎと For example, when using (Equation 2), if the number of repeated transmissions is 3, N=1 and the sequence length is 2. Also, if the number of repeated transmissions is 4, N=2 and the sequence length is 4.

[0086] In (Equation 1), code multiplexing is applied to slots or symbols of the sequence length from the beginning. Also, in (Equation 2), code multiplexing is applied to two slots or symbols from the beginning. Ｎ Applies to the minute slot or symbol.

[0087] Using the above relationship, in the first process, terminal 200 determines the sequence length to be used for the second signal from the number of times the second signal is repeatedly transmitted.

[0088] In addition, in the second processing, the base station 100 determines the sequence length from the number of times the second signal transmitted from the terminal 200 is repeatedly transmitted.

[0089] As described above, in this embodiment, the terminal 200 determines a sequence corresponding to a sequence length according to a first signal received from the base station 100 as a spreading code for code-multiplexing, and controls the second signal using the determined spreading code. The base station 100 also transmits the first signal, receives one or more signals including a second signal encoded with the spreading code, and acquires the second signal from the one or more received signals using the spreading code determined according to the first signal. In this way, spreading codes can be shared between the base station 100 and the terminal 200, and thus signals encoded using spreading codes can be separated from multiple code-multiplexed signals.

[0090] It is also possible to combine the method described in embodiment 2 and the method described in embodiment 3. For example, base station 100 may notify terminal 200 of information on sequence numbers and information on sequence lengths. Embodiment 4

[0091] In the first embodiment, an example has been described in which a spreading code for code multiplexing is determined in accordance with a first signal transmitted by the base station 100, and the determined spreading code is used to control the second signal. In the second embodiment, as a specific example of the first embodiment, a method has been described in which the base station 100 indicates a sequence number to the terminal 200. In the third embodiment, as another specific example of the first embodiment, a method has been described in which the base station 100 indicates a sequence length to the terminal 200. In the fourth embodiment, a method in which the sequence length and the sequence number are notified as a single piece of information will be described. Note that in the fourth embodiment, the wireless communication system 1, the base station 100, and the terminal 200 are the same as in the first embodiment, and therefore description thereof will be omitted. Furthermore, since the processing flow in the fourth embodiment is the same as in the second embodiment, description thereof will be omitted.

[0092] In the fourth embodiment, the base station 100 notifies the terminal 200 using a bit field configured with the number of bits corresponding to the sequence length.

[0093] The bit field, for example, notifies the sequence length by the number of bits, and notifies the sequence number by setting one of the multiple bits to "1." For example, if a bit field consisting of 4 bits indicates "1000," this indicates that the sequence length is 4 and the sequence number is 1. Also, for example, if a bit field consisting of 4 bits indicates "0100," this indicates that the sequence length is 4 and the sequence number is 2.

[0094] The bit field consisting of the number of bits corresponding to the sequence length is included in the RRC layer signal transmitted in step S50 and / or the control signal transmitted in step S70.

[0095] Then, in the first processing, terminal 200 determines the sequence length and sequence number to be used for the second signal from a bit field configured with the number of bits corresponding to the sequence length.

[0096] In addition, in the second processing, base station 100 determines the sequence length and sequence number to be used for the second signal from a bit field configured with the number of bits corresponding to the sequence length.

[0097] The bit field configured with the number of bits corresponding to the sequence length may be selected from a plurality of bit fields according to the sequence length, where the plurality of bit fields correspond to different sequence lengths, for example.

[0098] In addition, a bit field consisting of the number of bits corresponding to the sequence length may be made to correspond to the maximum sequence length supported, and the sequence length may be indicated by part of the bit field (for example, in the case of a 4-bit field, the first 2 bits or the last 2 bits), and the sequence number may be indicated by part of the bit field (for example, in the case of a 4-bit field, the last 2 bits or the first 2 bits).

[0099] Furthermore, when a bit field consisting of the number of bits corresponding to the sequence length is included in an RRC layer signal, for example, a bit field may be configured for each PUSCH List.

[0100] As described above, in the fourth embodiment, the terminal 200 determines a sequence corresponding to the sequence length and sequence number according to the first signal received from the base station 100 as a spreading code for code multiplexing, and controls the second signal using the determined spreading code. The base station 100 also transmits the first signal, receives one or more signals including a second signal encoded with the spreading code, and acquires the second signal from the one or more received signals using the spreading code determined according to the first signal. In this way, the spreading code can be shared between the base station 100 and the terminal 200, and therefore the signal encoded using the spreading code can be separated from the multiple code-multiplexed signals. Fifth embodiment

[0101] In the first embodiment, an example was described in which a spreading code for code multiplexing is determined in accordance with a first signal transmitted by the base station 100, and the determined spreading code is used to control the second signal. In the second embodiment, a method was described in which the base station 100 indicates a sequence number to the terminal 200. In the third embodiment, a method was described in which the base station 100 indicates a sequence length to the terminal 200. In the fourth embodiment, a method was described in which the sequence length and the sequence number are notified as a single piece of information. In the fifth embodiment, an example adapted to an NTN (Non-Terrestrial Network) will be described. In the fifth embodiment, the wireless communication system 1 and the terminal 200 are the same as in the first embodiment, and therefore description thereof will be omitted.

[0102] The base station 100 in the NTN will be described using Fig. 8. Fig. 8 is a diagram showing an example of a functional configuration block diagram of the base station 100 in the fifth embodiment. Note that the base station 100 in the NTN performs the same processing as the base stations 100 described in the first to fourth embodiments, for example.

[0103] A base station 100N in the NTN includes the functions of a service link providing system 150 and a normal (TN) base station 100 (hereinafter referred to as a ground station 160). The service link providing system 150 includes a gateway device 151 and an NTN payload unit 152. The gateway device 151 communicates with flying objects 153 (such as unmanned aerial vehicles and spacecraft) other than terrestrial wireless devices (terminals 200 and base stations 100). The flying object 153 is, for example, an unmanned aerial vehicle such as a High Altitude Platform Station (HAPS) or a spacecraft such as an artificial satellite, and includes at least an NTN payload unit 152. The flying object 153 receives a signal from the gateway device 151 (or the terminal 200) and transmits the received signal to the terminal 200 (or the gateway device 160) by operating as a repeater (for example, a repeater or relay station). The NTN payload unit 152 may also have some of the functions of the ground station 160 .

[0104] The communication path between the gateway device 151 and the NTN payload unit 152 is called a feeder link, and the communication path between the NTN payload unit 152 and the terminal 200 is called a service link. Note that the communication method used for the feeder link is not limited to NR, and any communication method may be used.

[0105] Furthermore, the base station 100N in the NTN may be configured to be divided into a CU (Centralized Unit) and a DU (Distributed Unit). The CU is connected to a core network, and the DU is connected to a terminal 200. A communication path between the CU and the DU may be connected via a fronthaul interface (F1 interface). Furthermore, a configuration may be adopted in which multiple DUs are connected to one CU.

[0106] 8 , data (DL data, downlink data) transmitted from the core network 300 to the terminal 200 is transmitted from the core network 300 to the ground station 160 of the base station 100N. The ground station 160 transmits the received data from the gateway device 151 to the flying object 153 using a feeder link. The flying object 153 operates as a repeater and transmits (transfers) the received radio signal to the terminal 200 using a service link.

[0107] Furthermore, data (UL data, uplink data) transmitted from the terminal device 200 to the core network 300 is transmitted from the terminal device 200 to the flying object 153 of the base station 100N using a service link. The flying object 153 then operates as a repeater and transmits (transfers) the received radio signal to the gateway device 151 using the feeder link. The gateway device 151 then transmits the received radio signal to the ground station 160. The ground station 160 then transmits the received data to the core network 300.

[0108] As described above, in the fifth embodiment, the methods described in the first to fourth embodiments are applied to the base station 100N in an NTN. In this way, spreading codes can be shared between the base station 100N and the terminal 200 by the methods described in the first to fourth embodiments, and the base station 100N can separate signals coded using spreading codes from multiple code-multiplexed signals. Hardware configuration of each device in each embodiment

[0109] The hardware configuration of each device in the wireless communication system of each embodiment will be described with reference to FIGS.

[0110] 9 is a diagram showing an example of the hardware configuration of the base station 100 (or the base station 100N). As shown in FIG. 9, the base station 100 (or the base station 100N) has, as hardware components, for example, an RF (Radio Frequency) circuit 320 equipped with an antenna 310, a CPU (Central Processing Unit) 330, a DSP (Digital Signal Processor) 340, a memory 350, and a network IF (Interface) 360. The CPU is connected via a bus so as to enable input and output of various signals and data signals. The memory 350 includes at least one of a RAM (Random Access Memory) such as an SDRAM (Synchronous Dynamic Random Access Memory), a ROM (Read Only Memory), and a flash memory, and stores programs, control information, and data signals.

[0111] The correspondence between the functional configuration of the base station 100 shown in Fig. 2 and the hardware configuration of the base station 100 shown in Fig. 9 will be described. The transmitter 111 and receiver 112 (or the wireless communication unit 110) are realized by, for example, an RF circuit 320, or an antenna 310 and an RF circuit 320. The control unit 120 is realized by, for example, a CPU 330, a DSP 340, a memory 350, a digital electronic circuit (not shown), etc. Examples of the digital electronic circuit include an ASIC (Application Specific Integrated Circuit), an FPGA (Field Programmable Gate Array), and an LSI (Large Scale Integration). The storage unit 130 is realized by, for example, the memory 350. The communication unit 140 is realized by, for example, a network IF 360.

[0112] Fig. 10 is a diagram showing an example of the hardware configuration of terminal 200. As shown in Fig. 10, terminal 200 has, as hardware components, an RF circuit 420 including, for example, an antenna 410, a CPU 430, a DSP 440, and a memory 450. Memory 450 includes at least one of a RAM such as an SDRAM, a ROM, and a flash memory, and stores programs, control information, and data signals.

[0113] The correspondence between the functional configuration of the terminal 200 shown in Fig. 3 and the hardware configuration of the terminal 200 shown in Fig. 10 will be described. The transmitter 211 and receiver 212 (or communication unit 210) are realized by, for example, an RF circuit 420, or an antenna 410 and an RF circuit 420. The control unit 220 is realized by, for example, a CPU 430, a DSP 440, a memory 450, a digital electronic circuit (not shown), etc. Examples of the digital electronic circuit include an ASIC, an FPGA, and an LSI. The storage unit 230 is realized by, for example, the memory 450.

[0114] The embodiments may be combined as appropriate within a range that does not cause any contradiction.

[0115] In each embodiment, examples of a base station and a terminal are described, but the disclosed technology is not limited to this and can be applied to various devices such as electronic devices mounted on automobiles, trains, airplanes, artificial satellites, etc., electronic devices transported by drones, etc., robots, AV equipment, home appliances, office equipment, vending machines, and other household equipment.

[0116] Furthermore, although the embodiments have been described using fifth-generation mobile communications as an example, the application of the disclosed technology is not limited to this. For example, the disclosed technology may be applied to mobile communications of different generations, such as sixth and seventh generations.

[0117] 1 Wireless communication system 100 100N Base station C10 Cell 110 Wireless communication unit 111 Transmitter 112 Receiver 120 Control unit 130 Memory unit 140 Communication unit 150 Service link providing system 151 Gateway device 152 NTN payload unit 153 Flying object 160 Ground station 200 Terminal 210 Communication unit 211 Transmitter 212 Receiver 220 Control unit 230 Memory unit 300 Core network 310 Antenna 320 RF circuit 330 CPU 340 DSP 350 Memory 360 Network IF 410 Antenna 420 RF circuit 430 CPU 440 DSP 450 Memory

Claims

1. A terminal having: a receiving unit that receives a first signal from a base station; a control unit that determines a spreading code to be used for a second signal in accordance with the first signal or first information contained in the first signal, and encodes the second signal using the determined spreading code; and a transmitting unit that transmits the second signal encoded using the spreading code to the base station.

2. The terminal according to claim 1, wherein the first information included in the first signal is information relating to the spreading code, the information relating to the spreading code is information indicating the sequence number and / or sequence length of the spreading code, and the control unit determines the sequence number and / or sequence length of the spreading code according to the information relating to the spreading code.

3. The terminal according to claim 2, wherein the first signal is a signal of an RRC (Radio Access Control) layer or a signal of a physical layer.

4. The terminal according to claim 3, wherein the information relating to the spreading code is a bitmap, and the bitmap is information indicating the sequence number and sequence length of the spreading code.

5. The terminal according to claim 2, wherein the first signal is an RRC (Radio Access Control) layer, and the first information is information set for each information element of an uplink time resource allocation list.

6. The terminal according to claim 1, wherein the control unit determines, as the spreading code, a sequence corresponding to a sequence number of the spreading code corresponding to an antenna port used for channel measurement.

7. The terminal according to claim 1, wherein the first signal is a physical layer signal, and the control unit determines a sequence to be used for the spreading code depending on a resource through which the physical layer signal is received.

8. The terminal according to claim 1, wherein the spreading code is an orthogonal code, and the orthogonal code is configured as a Walsh sequence or a DFT sequence.

9. The terminal according to claim 1, wherein the control unit determines the sequence length of the spreading code according to the number of times the second signal is repeatedly transmitted.

10. The terminal according to claim 9, wherein the sequence length of the spreading code is the same as the number of times the second signal is repeatedly transmitted.

11. A base station having: a transmitting unit that transmits a first signal to a terminal; a receiving unit that receives one or more signals including the first signal or a second signal encoded with a spreading code corresponding to first information contained in the first signal; and a control unit that performs processing to acquire the second signal using the spreading code.

12. The base station of claim 11, wherein the base station corresponds to a non-terrestrial communication system.

13. A wireless communication system comprising: a base station that transmits a first signal; and a terminal that receives the first signal, determines a spreading code to be used for a second signal in accordance with the first signal or first information contained in the first signal, encodes the second signal using the determined spreading code, and transmits the second signal encoded using the spreading code to the base station.

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