Non-regenerative relay communication system

Abstract

To provide a non-reproduction relay communication system capable of non-reproduction relay communication using full-duplex communication.SOLUTION: A non-reproduction relay communication system performs non-reproduction relay communication between a first communication station and a second communication station via a relay station. The non-reproduction relay communication system includes: first delay calculation means for calculating, based on a signal, a first signal-to-noise ratio in communication between the first communication station and the relay station, and first propagation delay indicating delay in communication between the first communication station and the relay station; second delay calculation means for calculating, based on a signal, a second signal-to-noise ratio in communication between the second communication station and the relay station, and second propagation delay indicating delay in communication between the second communication station and the relay station; and communication determination means for performing the non-reproduction relay communication based on the first signal-to-noise ratio and the first propagation delay, and the second signal-to-noise ratio and the second propagation delay.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] This invention relates to a non-regenerative relay communication system. [Background technology]

[0002] In recent years, there has been a growing need to achieve ultra-low latency communication using 5G, with delays of less than sub-milliseconds. This ultra-low latency communication is expected to enable technologies such as remote control of mobility terminals, including autonomous vehicles, and xR (cross-reality).

[0003] On the other hand, relay communication using relay stations is essential to expand the coverage area of ​​this ultra-low latency communication. For this reason, relay communication using regenerative relay, which performs demodulation and decoding at the relay station and then re-encodes and modulates the signal, has been standardized in sidelinks and other applications.

[0004] However, when using regenerative relay communication, delays of several milliseconds or more occur during relay processing, which is problematic because it prevents the expansion of ultra-low latency communication coverage. To address this problem, there is growing interest in non-regenerative relay, which does not perform demodulation and decoding at the relay station, but only performs simple processing and amplification. For this reason, non-regenerative relay communication systems, such as those described in Non-Patent Documents 1 and 2, are attracting attention.

[0005] Non-Patent Document 1 discloses a non-regenerative relay communication method in half-duplex communication. Non-Patent Document 2 discloses a method for using the same time slot for transmission and reception in non-regenerative relay communication and suppressing self-interference with an FIR filter. [Prior art documents] [Non-patent literature]

[0006] [Non-Patent Document 1] H. Chen. AB Gershman, and S. Shahbazpanahi, "Filter-and-Forward Distributed Beamforming in Relay Networks with Frequency Selective Fading," IEEE Trans. On Signal Processing, vol. 58, no. 3, March 2010. [Non-Patent Document 2] Noguchi, Hayashi, Kaneko, and Sakai, "Single-Frequency Full-Duplex Wireless Relay for Frequency Domain Equalization Systems," IEICE Technical Report, vol. SIP2011-109, January 2012. [Overview of the Initiative] [Problems that the invention aims to solve]

[0007] However, the technology disclosed in Non-Patent Document 1 assumes non-regenerative relay communication in half-duplex communication and does not assume the use of the same time slot for transmission and reception. Therefore, it is problematic that non-regenerative relay communication using full-duplex communication cannot be performed. Furthermore, the technology disclosed in Non-Patent Document 2 assumes that the relay station has multiple antennas such as array antennas, and that the antennas for transmission and reception are separate. Therefore, for example, when performing non-regenerative relay communication using full-duplex communication, it is problematic that separate channel estimation is required for the transmission and reception antennas in order to reduce self-interference.

[0008] This invention was derived to solve these problems and aims to provide a non-regenerative relay communication system that enables non-regenerative relay communication using full-duplex communication. [Means for solving the problem]

[0009] The non-regenerative relay communication system according to the first invention is a non-regenerative relay communication system that performs non-regenerative relay communication between a first communication station and a second communication station via a relay station, comprising: a first delay calculation means that calculates a first signal-to-noise ratio in the communication between the first communication station and the relay station and a first propagation delay indicating the delay in the communication between the first communication station and the relay station based on signals transmitted or received in the communication between the relay station and the first communication station; a second delay calculation means that calculates a second signal-to-noise ratio in the communication between the second communication station and the relay station and a second propagation delay indicating the delay in the communication between the second communication station and the relay station based on signals transmitted or received in the communication between the relay station and the second communication station; and performing the non-regenerative relay communication based on the first signal-to-noise ratio and first propagation delay calculated by the first delay calculation means and the second signal-to-noise ratio and second propagation delay calculated by the second delay calculation means. To determine Communication decision-making means and of Preparation - A first matrix calculation means for calculating a first channel matrix showing the changes in communication signals through each channel between the two or more relay stations and the first communication station based on signals transmitted or received in communication between the two or more relay stations and the first communication station; a second matrix calculation means for calculating a second channel matrix showing the changes in communication signals through each channel between the two or more second communication stations and the first communication station based on signals transmitted or received in communication between the two or more second communication stations and the first communication station; and the first channel matrix calculated by the first matrix calculation means The system further comprises: a noise ratio calculation means for calculating the third signal-to-noise ratio for each communication between the station and two or more relay stations, and the fourth signal-to-noise ratio for each communication between the first station and two or more second communication stations from the second communication path matrix calculated by the second matrix calculation means; and a selection means for selecting the second communication station and the relay station that perform the non-regenerative relay communication from among the two or more relay stations and the two or more second communication stations, based on the third signal-to-noise ratio and the fourth signal-to-noise ratio calculated by the noise ratio calculation means. It is characterized by the following.

[0010] The non-regenerative relay communication system according to the second invention is a non-regenerative relay communication system that performs non-regenerative relay communication between a first communication station and a second communication station via a relay station, comprising: a first delay calculation means that calculates a first signal-to-noise ratio in the communication between the first communication station and the relay station and a first propagation delay indicating the delay in the communication between the first communication station and the relay station based on signals transmitted or received in the communication between the relay station and the first communication station; a second delay calculation means that calculates a second signal-to-noise ratio in the communication between the second communication station and the relay station and a second propagation delay indicating the delay in the communication between the second communication station and the relay station based on signals transmitted or received in the communication between the relay station and the second communication station; and performing the non-regenerative relay communication based on the first signal-to-noise ratio and first propagation delay calculated by the first delay calculation means and the second signal-to-noise ratio and second propagation delay calculated by the second delay calculation means. To determine Communication decision-making means and The communication determination means comprises a processing delay calculation means that calculates a processing delay indicating a delay for processing self-interference in communication based on signals transmitted or received in communication between the relay station and the first communication station, and the communication determination means calculates an allowable delay indicating an allowable amount of delay in communication between the relay station and the second communication station based on a first propagation delay calculated by the first delay calculation means and a processing delay calculated by the processing delay calculation means, and determines whether to perform the non-regenerative relay communication based on the calculated allowable delay, the first signal-to-noise ratio, the second signal-to-noise ratio and the second propagation delay. It is characterized by the following.

[0011] The non-regenerative relay communication system according to the third invention is further characterized in that, in the first invention, it comprises processing delay calculation means for calculating a processing delay indicating a delay for processing self-interference in communication based on signals transmitted or received in communication between the relay station and the first communication station.

[0012] The non-regenerative relay communication system according to the fourth invention is 2 In the invention, The communication determination means performs the non-regenerative relay communication if the calculated allowable delay is greater than or equal to the second propagation delay, and the first signal-to-noise ratio and the second signal-to-noise ratio are greater than or equal to a threshold. It is characterized by the following.

[0013] The non-regenerative relay communication system according to the fifth invention is the 1 In the invention, The selection means selects the relay station in which the third signal-to-noise ratio calculated by the noise ratio calculation means is greater than the threshold, and selects the second communication station in which the fourth signal-to-noise ratio calculated by the noise ratio calculation means is less than the threshold. It is characterized by the following: [Effects of the Invention]

[0015] First Invention ~ 5 According to the invention, the communication decision means performs non-regenerative relay communication based on a first signal-to-noise ratio and a first propagation delay, and a second signal-to-noise ratio and a second propagation delay. This makes it possible to calculate, for example, the first signal-to-noise ratio and a first propagation delay, and the second signal-to-noise ratio and a second propagation delay based on a notification signal for performing non-regenerative relay communication. Therefore, even when using full-duplex communication, efficient non-regenerative relay communication is possible in such a way that the relay signal does not exceed the cyclic plex length when it is received at the second communication station.

[0016] In particular, 1 According to the invention, the selection means selects a second communication station and a relay station to perform non-regenerative relay communication from among two or more relay stations and two or more second communication stations, based on the respective third signal-to-noise ratio and the respective fourth signal-to-noise ratio. This makes it possible to calculate the signal-to-noise ratio in each line based on the reference signal and select the relay station and second communication station to be communicated with. As a result, more efficient non-regenerative relay communication becomes possible.

[0017] In particular, according to the third invention, the processing delay calculation means calculates the processing delay based on the signal transmitted or received in the communication between the relay station and the first communication station. This makes it possible to calculate the processing delay based on, for example, a reference signal. Therefore, it is possible to suppress self-interference even when using full-duplex communication.

[0018] In particular, 2 According to the invention, the communication decision means performs non-regenerative relay communication based on the calculated allowable delay, the first signal-to-noise ratio, the second signal-to-noise ratio, and the second propagation delay. This allows for a comparison of the allowable delay and the second propagation delay to determine whether to perform non-regenerative relay communication, thus enabling more efficient non-regenerative relay communication.

[0019] In particular, 4 According to the invention, the communication determination means performs non-regenerative relay communication if the calculated allowable delay is greater than or equal to the second propagation delay, and the first signal-to-noise ratio and the second signal-to-noise ratio are greater than or equal to a threshold. Therefore, even when using full-duplex communication, efficient non-regenerative relay communication is possible without exceeding the cyclic plex length when the relay signal is received at the second communication station.

[0020] In particular, 5 According to the invention, the selection means selects a relay station whose third signal-to-noise ratio is greater than a threshold, and a second communication station whose fourth signal-to-noise ratio is less than a threshold. This enables more efficient non-regenerative relay communication. [Brief explanation of the drawing]

[0021] [Figure 1] Figure 1(a) is a schematic diagram of a non-regenerative relay communication system using a single base station. Figure 1(b) is a schematic diagram of a non-regenerative relay communication system using a central base station and distributed base stations. [Figure 2] Figure 2(a) is a schematic diagram showing an example of the configuration of the control device in this embodiment, and Figure 2(b) is a schematic diagram showing an example of the functions of the control device in this embodiment. [Figure 3]Figure 3(a) is a schematic diagram showing an example of the configuration of a relay station with one antenna in this embodiment, and Figure 3(b) is a schematic diagram showing an example of the configuration of a relay station with two antennas in this embodiment. [Figure 4] Figure 4 is a schematic diagram showing an example of the configuration of the baseband signal processing circuit in this embodiment. [Figure 5] Figure 5 shows the processing flow of a non-regenerative relay communication system. [Modes for carrying out the invention]

[0022] The non-regenerative relay communication system to which the present invention is applied will be described in detail below with reference to the drawings.

[0023] Figure 1(a) is a schematic diagram of the non-regenerative relay communication system 100 when using one base station 2. As shown in Figure 1(a), the non-regenerative relay communication system 100 comprises a control device 1, a base station 2 connected to the control device 1, a relay station 3 that communicates with the base station 2, and a terminal station 4 that communicates with the base station 2 and the relay station 3. The non-regenerative relay communication system 100 may also comprise two or more relay stations 3 and two or more terminal stations 4.

[0024] Figure 1(b) is an overall schematic diagram of a non-regenerative relay communication system 100 using a central base station 5 and distributed base stations 6. As shown in Figure 1(b), the non-regenerative relay communication system 100 comprises a control device 1, a central base station 5 connected to the control device 1, distributed base stations 6 that communicate with the central base station 5, relay stations 3 that communicate with the distributed base stations 6, and terminal stations 4 that communicate with the distributed base stations 6 and relay stations 3. The non-regenerative relay communication system 100 may also comprise two or more distributed base stations 6, two or more relay stations 3, and two or more terminal stations 4.

[0025] The control device 1 controls non-regenerative relay communication. The control device 1 may be an electronic device such as a personal computer (PC), or it may be an electronic device such as a smartphone, tablet terminal, wearable terminal, IoT (Internet of Things) device, or single-board computer.

[0026] Base station 2 is a communication station that communicates with terminal station 4. Base station 2 may be a first communication station BS that transmits signals to terminal station 4, or a second communication station UE that receives signals transmitted from terminal station 4. Base station 2 may also perform non-regenerative relay communication with terminal station 4 via relay station 3. Base station 2 includes a radio 21 for processing communication signals, a control circuit 22 for controlling communication connected to the radio 21, and an antenna 23 for transmitting and receiving signals connected to the radio 21. Base station 2 may have two or more antennas 23, such as an array antenna.

[0027] Terminal station 4 is composed of wireless communication-capable terminal devices such as a notebook personal computer (PC), a mobile terminal, a smartphone, a tablet terminal, or a wearable terminal. Terminal station 4 may be a first communication station BS that transmits signals to base station 2, or a second communication station UE that receives signals transmitted from base station 2. Terminal station 4 includes a radio 41 for processing communication signals, a control circuit 42 for controlling communication connected to the radio 41, and an antenna 43 for transmitting and receiving signals connected to the radio 41. Terminal station 4 may have two or more antennas 43, such as an array antenna.

[0028] Relay station 3 acts as a so-called repeater between base station 2 and terminal station 4, and also acts as an interface with public communication networks such as the Internet. In other words, relay station 3 is responsible for relaying data, enabling base station 2 and terminal station 4 to send and receive data with public communication networks such as the Internet.

[0029] Next, an example of the control device 1 in this embodiment will be described with reference to Figure 2. Figure 2(a) is a schematic diagram showing an example of the configuration of the control device 1 in this embodiment, and Figure 2(b) is a schematic diagram showing an example of the functions of the control device 1 in this embodiment.

[0030] The control device 1, as shown in Figure 2(a) for example, comprises a housing 10, a CPU (Central Processing Unit) 101, a ROM (Read Only Memory) 102, a RAM (Random Access Memory) 103, a storage unit 104, and I / F 105-107. The CPU 101, ROM 102, RAM 103, storage unit 104, and I / F 105-107 are connected by an internal bus 110.

[0031] The CPU 101 controls the entire control unit 1. The ROM 102 stores the operation code of the CPU 101. The RAM 103 is a working area used when the CPU 101 is operating. The storage unit 104 stores various types of information. The storage unit 104 can be a data storage device such as an HDD (Hard Disk Drive), SSD (Solid State Drive), SD card, or miniSD card. For example, the control unit 1 may also have a GPU (Graphics Processing Unit), which is not shown.

[0032] I / F105 is an interface for sending and receiving various types of information via a communication network. I / F106 is an interface for sending and receiving information with the input unit 108. For example, a keyboard is used as the input unit 108, and users of the control device 1 input various types of information or control commands for the control device 1 via the input unit 108. I / F107 is an interface for sending and receiving various types of information with the display unit 109. The display unit 109 outputs various types of information, such as specific results stored in the storage unit 104, or the processing status of the control device 1. A display is used as the display unit 109, and for example, a touch panel type may be used.

[0033] The display unit 109 displays various information. For example, the display unit 109 displays information about the relay station 3 that performs non-regenerative relay communication.

[0034] Figure 2(b) is a schematic diagram showing an example of the functions of the control device 1. The control device 1 comprises an acquisition unit 11, a calculation unit 12, a selection unit 13, a storage unit 14, an output unit 15, and a judgment unit 16. The acquisition unit 11, calculation unit 12, selection unit 13, storage unit 14, output unit 15, and judgment unit 16 shown in Figure 2(b) are realized by the CPU 101 executing a program stored in the storage unit 104, etc., using the RAM 103 as a working area, and may be controlled by artificial intelligence, for example.

[0035] The acquisition unit 11 acquires various types of information. For example, the acquisition unit 11 acquires information such as a reference signal transmitted from the relay station 3 and received by the base station 2. The frequency and period at which the acquisition unit 11 acquires various types of information are arbitrary.

[0036] The calculation unit 12 processes the information acquired by the acquisition unit 11. The calculation unit 12 calculates, for example, the signal-to-noise ratio or propagation delay based on the reference signal information acquired by the acquisition unit 11. The calculation unit 12 calculates the first signal-to-noise ratio Γ in the communication between the first communication station BS and the relay station 3 based on the signal transmitted or received in the communication between the relay station 3 and the first communication station BS. BS → Ri And the first propagation delay τ, which indicates the delay in communication between the first communication station BS and the relay station 3. BS → Ri The calculation unit 12 calculates the second signal-to-noise ratio Γ in the communication between the second communication station UE and the relay station 3, based on the signals transmitted or received in the communication between the relay station 3 and the second communication station UE. UE → Ri The second propagation delay τ indicates the delay in communication between the second communication station UE and the relay station 3. UE → RiIt calculates the following. The calculation unit 12 is based on the signals transmitted or received in the communication between two or more relay stations 3 and the first communication station BS, and shows the change of the communication signal through each communication path between two or more relay stations 3 and the first communication station BS. The first communication path matrix H R → BS is calculated. The calculation unit 12 calculates a second communication path matrix showing the change of the communication signal through each communication path between two or more second communication stations UE and the first communication station BS based on the signals transmitted or received in the communication between two or more second communication stations UE and the first communication station BS. The calculation unit 12, for example, from the calculated first communication path matrix H R → BS calculates each third signal-to-noise ratio in the communication between the first communication station BS and two or more relay stations 3, and each fourth signal-to-noise ratio in the communication between the first communication station BS and two or more second communication stations UE from the calculated second communication path matrix. The calculation unit 12, for example, based on the signals transmitted or received in the communication between the relay station 3 and the first communication station BS, calculates a processing delay τ R,i indicating the delay for processing self-interference in the communication. The calculation unit 12, for example, based on the calculated first propagation delay τ BS → Ri and the calculated processing delay τ R,i calculates an allowable delay τ UE → R,max indicating the allowable amount of delay in the communication between the relay station 3 and the second communication station UE.

[0037] The selection unit 13 selects a relay station 3 that performs non-regenerative relay communication based on the signal-to-noise ratio calculated by the calculation unit 12. The selection unit 13, for example, selects a second communication station UE and a relay station 3 that perform non-regenerative relay communication from among two or more relay stations and two or more second communication stations UE based on each third signal-to-noise ratio and each fourth signal-to-noise ratio calculated by the calculation unit 12.

[0038] The determination unit 16 determines whether to perform non-regenerative relay communication based on the propagation delay and signal-to-noise ratio calculated by the calculation unit 12. The determination unit 16, for example, the first signal-to-noise ratio Γ calculated by the calculation unit 12 BS → Riand the first propagation delay τ BS → Ri and the second signal-to-noise ratio Γ UE → Ri and the second propagation delay τ UE → Ri Based on this, a decision is made on whether to perform non-regenerative relay communication.

[0039] The memory unit 14 retrieves various information stored in the storage unit 104 as needed. The memory unit 14 stores various information acquired or output by the acquisition unit 11, the calculation unit 12, the selection unit 13, and the judgment unit 16 in the storage unit 104.

[0040] The output unit 15 outputs various information. The output unit 15 transmits control commands for non-regenerative relay communication to the base station 2, for example, via the I / F 105.

[0041] Figure 3(a) is a schematic diagram showing an example of the configuration of the relay station 3 in this embodiment when there is one antenna. The relay station 3 comprises a radio 31 for processing communication signals, a control circuit 32 for controlling communication connected to the radio 31, and an antenna 33 for transmitting and receiving signals connected to the radio 31.

[0042] The radio 31 includes a circulator 311 connected to an antenna 33, a receiver 313 connected to the circulator 311, an ADC (Analog Digital Converter) 314 connected to the receiver 313, a baseband signal processing circuit 315 connected to the ADC 314, a control circuit 32 connected to the baseband signal processing circuit 315, a DAC (Digital Analog Converter) 316 connected to the baseband signal processing circuit 315, a transmitter 317 connected to the DAC 316, and an interference rejection circuit 312 connected to the transmitter 317 and the receiver 313.

[0043] The circulator 311 outputs a signal to the receiver 313. The isolation of the circulator 311 is approximately 30 dB, but this is not limited to this value, and any isolation value may be used.

[0044] Receiver 313 is a device that receives signals. Receiver 313 outputs the received signals to ADC314.

[0045] The ADC314 converts the output analog signal into a digital signal. The ADC314 then outputs the converted digital signal to the baseband signal processing circuit 315.

[0046] The baseband signal processing circuit 315 is a Finite Impulse Response (FIR) filter that filters the output digital signal. The baseband signal processing circuit 315 outputs the filtered signal to the control circuit 32. The baseband signal processing circuit 315 may also output a signal to the DAC 316 to suppress self-interference output from the control circuit 32.

[0047] The DAC316 converts the output signal into an analog signal. The DAC316 then outputs the converted analog signal to the transmitter 317.

[0048] Transmitter 317 upconverts the analog signal of the baseband signal and transmits the signal via antenna 33. Transmitter 317 may also output a signal to the interference rejection circuit 312 to suppress self-interference.

[0049] The interference suppression circuit 312 is an IS (Interference Suppression) circuit. The interference suppression circuit 312 suppresses self-interference by combining a signal to suppress self-interference with the signal received by the receiver 313.

[0050] Figure 3(b) is a schematic diagram showing an example of the configuration of the relay station 3 in this embodiment when there are two antennas. The relay station 3 comprises a radio 31, a control circuit 32 connected to the radio 31, and a plurality of antennas 33 connected to the radio 31. The relay station 3 may also use, for example, an array antenna as the antenna 33.

[0051] The radio 31 comprises a plurality of circulators 311 independently connected to each antenna 33, a plurality of receivers 313 independently connected to each circulator 311, a plurality of ADCs (Analog Digital Converters) 314 independently connected to each receiver 313, a baseband signal processing circuit 315 connected to each ADC 314, a control circuit 32 connected to the baseband signal processing circuit 315, a plurality of DACs (Digital Analog Converters) 316 connected to the baseband signal processing circuit 315, a plurality of transmitters 317 independently connected to each DAC 316, and a plurality of interference rejection circuits 312 independently connected to each transmitter 317 and each receiver 313.

[0052] Figure 4 is a schematic diagram showing an example of the configuration of the baseband signal processing circuit 315 in this embodiment. In Figure 4, w k,nD This is the kth element (k=1 to N). ant The coefficients (complex numbers) of the digital filter for antenna 33 of ) are shown, and w RX,k and lol TX,k These represent the weights of antenna 33 during reception and transmission, respectively. Also, D represents the delay circuit 320. The baseband signal processing circuit 315 is, for example, an FIR (Finite Impulse Response) filter, which is a filter that utilizes a finite impulse response. The baseband signal processing circuit 315 for the k-th antenna of relay station 3 is N D,k Stage delay 320 and complex number weight vector w k ={w k,0 ,···,w k,ND,k-1 It is composed of ]. Number of stages of delay circuit 320 N D,k And weight lol k This is determined in the control circuit 32. By performing optimization with constraints on the number of taps, the processing delay τ is reduced. R,i This makes it possible to control the delay. In addition, the baseband signal processing circuit 315 may increase the number of delay units 320 of the FIR filter to satisfy a given delay time Δi.

[0053] Next, the operation of the processing of the non-regenerative relay communication system 100 will be explained using Figure 5. First, in step S1, two or more relay stations 3 that are candidates for relaying non-regenerative relay communication and two or more second communication stations UE that seek low-latency non-regenerative relay communication transmit an uplink reference signal to the first communication station BS. In this case, the first communication station BS may be a base station 2 or a terminal station 4. Also, the second communication station UE may be a base station 2 or a terminal station 4. In step S1, the first communication station BS receives the uplink reference signal and generates a first channel matrix H that shows the changes in communication signals through each communication channel between the two or more relay stations 3 and the first communication station BS. R → BS The second channel matrix H shows the changes in communication signals through each channel between the first communication station BS and two or more second communication stations UE. UE → BS And, are measured. The first communication station BS is the first communication channel matrix H R → BS and the second channel matrix H UE → BS The information is sent to the control device 1. The channel matrix H is a complex number of the propagation path response, for example, the received signal Y R → BS The transmission signal is X R → BS Y R → BS =H R → BS X R → BS This can be shown.

[0054] Furthermore, in step S1, when relay station 3 uses full-duplex communication, when transmitting the reference signal, the signal transmitted from the antenna leaks into the receiver, causing self-interference. In step S1, relay station 3 uses the reference signal to determine a processing delay τ, which indicates a delay for handling self-interference in communication. R,i The relay station 3 measures self-interference from the reference signal, sets RF and digital filters for interference suppression, and calculates the processing delay τ. R,iThe relay station 3 uses, for example, a baseband signal processing circuit 315 to calculate the processing delay τ. R,i This calculates the result. Therefore, self-interference can be suppressed even when using full-duplex communication.

[0055] Next, in step S2, the control device 1 receives the first communication channel matrix H notified in step S1. R → BS From this, the third signal-to-noise ratio for each communication between the first communication station BS and two or more relay stations 3 is calculated. In step S2, the control device 1 receives the second communication path matrix H notified in step S1. UE → BS From this, the control device 1 calculates the fourth signal-to-noise ratio for each communication between the first communication station BS and two or more second communication stations UE. In step S2, the control device 1 selects a second communication station UE and a relay station 3 from among two or more relay stations 3 and two or more second communication stations UE to perform non-regenerative relay communication, based on the respective third signal-to-noise ratios and the respective fourth signal-to-noise ratios. In this case, the control device 1 selects a relay station 3 whose respective third signal-to-noise ratio is greater than the threshold, and a second communication station UE whose respective fourth signal-to-noise ratio is less than the threshold. For example, the control device 1 selects the calculated fourth signal-to-noise ratio as a desired value Γ for performing low-latency non-regenerative relay communication. L If it is lower than, #j(j=0~N) UE -1) The second communication station UE is the relay target. The control device 1 will set the calculated third signal-to-noise ratio to the desired value Γ R =Γ L +M R If it is greater than, #i(i=0~N) R -1) Relay station 3 will be the relay target. In this case, # indicates the number. Here, M R This indicates the margin that the third signal-to-noise ratio adds to the desired value. The signal-to-noise ratio is a ratio that indicates the amount of noise relative to the signal. The signal-to-noise ratio may also be, for example, the signal-to-noise power ratio, the signal-to-noise amplitude ratio, etc.

[0056] Next, in step S3, the control device 1 grants permission for non-regenerative relay communication to the relay station 3 from the first communication station BS and specifies the desired signal-to-noise ratio Γ of the second communication station UE to be relayed.L,j Notify.

[0057] Next, in step S4, the relay station 3 calculates the first signal-to-noise ratio Γ BS → Ri in the communication between the first communication station BS and the relay station 3 from the notification signal notified in step S3, and the first propagation delay τ BS → Ri indicating the delay in the communication between the first communication station BS and the relay station 3. Also, in step S4, the relay station 3 calculates the first propagation delay τ BS → Ri and, based on the first propagation delay τ R,i and the processing delay τ UE → R,max calculated in step S1, calculates the allowable delay τ UE → R,max indicating the allowable amount of delay in the communication between the relay station 3 and the second communication station UE. In such a case, the allowable delay τ

Equation

[0058] In such a case, T[[ID=3%8]] CP is the cyclic prefix length, and δ indicates the measurement deviation margin. [[ID=4%1]]

[0059] Also, in step S4, when using the relay station 3 equipped with a plurality of antennas 33 as the relay station 3, from the notification signal notified in step S3, the antenna weights w R → BS =(w R → BS,0 ,w R → BS,1 ,···,w R → BS,Nant −₁) between the first communication station BS and the relay station 3 are optimized, and the first signal-to-noise ratio Γ BS →<00%092>and the first propagation delay τ BS → Ri are calculated.

[0060] Next, in step S5, the relay station 3 calculates a second signal-to-noise ratio Γ UE → Ri in the communication between the second communication station UE and the relay station 3 based on the reference signal, and a second propagation delay τ UE → Ri indicating the delay in the communication between the second communication station UE and the relay station 3. In such a case, the i-th relay station 3 receives an uplink reference signal from the j-th second communication station UE, and calculates the second signal-to-noise ratio Γ UE → Ri and the second propagation delay τ UE → Ri based on the uplink reference signal.

[0061] Also, in step S5, when using a relay station 3 equipped with a plurality of antennas 33 as the relay station 3, the relay station 3 optimizes an antenna weight w R → UE between the second communication station UE and the relay station 3 based on the reference signal, and calculates the second signal-to-noise ratio Γ UE → Ri and the second propagation delay τ UE → Ri indicating the delay in the communication between the second communication station UE and the relay station 3.

[0062] Next, in step S6, based on the first signal-to-noise ratio Γ calculated in step S4 BS → Ri and the first propagation delay τ BS → Ri and the second signal-to-noise ratio Γ calculated in step S5 UE → Ri and the second propagation delay τ UE → Ri it is determined whether to perform non-regenerative relay communication. Also, in step S6, based on the calculated allowable delay τ UE → R,max and the first signal-to-noise ratio Γ BS → Ri and the second signal-to-noise ratio Γ UE → Ri and the second propagation delay τ UE → Ri it is determined whether to perform non-regenerative relay communication. In such a case, the relay station 3 uses the calculated allowable delay τUE → R,max The second propagation delay τ UE → Ri The above is the first signal-to-noise ratio Γ BS → Ri and the second signal-to-noise ratio Γ UE → Ri If both conditions are above a threshold, non-regenerative relay communication may be performed. For example, relay station 3 may decide to perform non-regenerative relay communication if equation (2) is satisfied.

number

[0063] In step S7, if it is determined in step S6 to perform non-regenerative relay communication, non-regenerative relay communication is performed between the first communication station BS and the second communication station UE via relay station 3. Also, in step S7, when non-regenerative relay communication is performed, the cyclic plex length T is used when the second communication station UE, the relay destination, receives the signal. CP To ensure that the transmission fits within the specified time, an additional delay time ?i may be added at relay station #i before transmission.

[0064] While embodiments of the present invention have been described, these embodiments are presented as examples only and are not intended to limit the scope of the invention. Such novel embodiments can be implemented in a variety of other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their variations are included within the scope and spirit of the invention, as well as within the scope of the invention and its equivalents as described in the claims. [Explanation of Symbols]

[0065] 1. Control device 2 base station 3 relay stations 4 Terminal Stations 5. Central base station 6 Distributed base station 10 cabinets 11 Acquisition Department 12 Calculation Section 13 Selection Section 14 Storage section 15 Output section 16 Judgment Department 21 Radio 22 Control circuits 23 Antennas 31 Radio 32 Control circuits 33 Antennas 41 Radio 42 Control circuits 43 Antenna 100 Non-regenerative relay communication systems 101 CPU 102 ROM 103 RAM 104 Preservation Department 105 I / F 106 I / F 107 I / F 108 Input section 109 Display section 110 Internal bus 311 Circulator 312 Interference rejection circuit 313 Receiver 314 ADC 315 Baseband signal processing circuit 316 DAC 317 Transmitter 320 delays BS 1st communication station UE 2nd Communications Station

Claims

1. In a non-regenerative relay communication system that performs non-regenerative relay communication between a first communication station and a second communication station via a relay station, A first delay calculation means calculates a first signal-to-noise ratio in communication between the first communication station and the relay station, and a first propagation delay indicating the delay in communication between the first communication station and the relay station, based on signals transmitted or received in communication between the relay station and the first communication station. A second delay calculation means calculates a second signal-to-noise ratio in communication between the second communication station and the relay station, and a second propagation delay indicating the delay in communication between the second communication station and the relay station, based on signals transmitted or received in communication between the relay station and the second communication station. The system includes a communication determination means that determines whether to perform the non-regenerative relay communication based on the first signal-to-noise ratio and first propagation delay calculated by the first delay calculation means and the second signal-to-noise ratio and second propagation delay calculated by the second delay calculation means, A first matrix calculation means calculates a first communication path matrix showing the changes in communication signals through each communication path between the two or more relay stations and the first communication station, based on signals transmitted or received in communication between the two or more relay stations and the first communication station. A second matrix calculation means calculates a second channel matrix showing the changes in communication signals through each channel between the two or more second communication stations and the first communication station, based on signals transmitted or received in communication between the two or more second communication stations and the first communication station. A noise ratio calculation means for calculating the third signal-to-noise ratio for each communication between the first communication station and two or more relay stations from the first communication path matrix calculated by the first matrix calculation means, and the fourth signal-to-noise ratio for each communication between the first communication station and two or more second communication stations from the second communication path matrix calculated by the second matrix calculation means, The system further includes a selection means that, based on the respective third signal-to-noise ratios and the respective fourth signal-to-noise ratios calculated by the noise ratio calculation means, selects from among two or more relay stations and two or more second communication stations the second communication station and the relay station that will perform the non-regenerative relay communication. A non-regenerative relay communication system characterized by the following.

2. In a non-regenerative relay communication system that performs non-regenerative relay communication between a first communication station and a second communication station via a relay station, A first delay calculation means calculates a first signal-to-noise ratio in communication between the first communication station and the relay station, and a first propagation delay indicating the delay in communication between the first communication station and the relay station, based on signals transmitted or received in communication between the relay station and the first communication station. A second delay calculation means calculates a second signal-to-noise ratio in communication between the second communication station and the relay station, and a second propagation delay indicating the delay in communication between the second communication station and the relay station, based on signals transmitted or received in communication between the relay station and the second communication station. A communication determination means that determines whether to perform the non-regenerative relay communication based on the first signal-to-noise ratio and first propagation delay calculated by the first delay calculation means and the second signal-to-noise ratio and second propagation delay calculated by the second delay calculation means, The system includes a processing delay calculation means that calculates a processing delay indicating a delay for processing self-interference in communication, based on signals transmitted or received in communication between the relay station and the first communication station, The communication determination means calculates an allowable delay indicating the allowable amount of delay in communication between the relay station and the second communication station based on the first propagation delay calculated by the first delay calculation means and the processing delay calculated by the processing delay calculation means, and determines whether to perform the non-regenerative relay communication based on the calculated allowable delay, the first signal-to-noise ratio, the second signal-to-noise ratio, and the second propagation delay. A non-regenerative relay communication system characterized by the following.

3. The system further includes a processing delay calculation means that calculates a processing delay indicating a delay for processing self-interference in communication, based on signals transmitted or received in communication between the relay station and the first communication station. A non-regenerative relay communication system according to claim 1, characterized by the following:

4. The communication determination means performs the non-regenerative relay communication if the calculated allowable delay is greater than or equal to the second propagation delay, and the first signal-to-noise ratio and the second signal-to-noise ratio are greater than or equal to a threshold. A non-regenerative relay communication system according to claim 2, characterized by the above.

5. The selection means selects the relay station in which the third signal-to-noise ratio calculated by the noise ratio calculation means is greater than a threshold, and selects the second communication station in which the fourth signal-to-noise ratio calculated by the noise ratio calculation means is less than a threshold. A non-regenerative relay communication system according to claim 1, characterized by the following:

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