Non-regenerative relay communication system

Abstract

Provided is a non-regenerative relay communication system capable of performing non-regenerative relay communication using full-duplex communication. 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, the non-regenerative relay communication system being characterized by comprising: a first delay calculation unit that calculates a delay between the first communication station and the second communication station; a calculation unit that calculates, from a signal, a first signal-to-noise ratio of communication between the first communication station and the relay station, and a first propagation delay indicating a delay of communication between the first communication station and the relay station; a second delay calculation unit that calculates a second signal-to-noise ratio of communication between the second communication station and the relay station and a second propagation delay indicating a delay of communication between the second communication station and the relay station on the basis of a signal; and a communication determination means that performs the non-regenerative relay communication on the basis of the first signal-to-noise ratio and the first propagation delay, and the second signal-to-noise ratio and the second propagation delay.

Description

Technical Field

[0001] The present invention relates to a non-regenerative relay communication system. Background Art

[0002] In recent years, 5G communication has become necessary to achieve ultra-low latency communication, which is to communicate with a latency of less than sub-milliseconds. For example, this ultra-low latency communication is expected to realize technologies such as remote control of mobile terminals including self-driving cars and xR (Cross Reality).

[0003] On the other hand, in order to expand the coverage of the communication area of ​​the ultra-low latency communication, relay communication using a relay station is essential. Therefore, relay communication using regenerative relay, which means encoding and modulation again after demodulation and decoding at the relay station, has been standardized through sidelinks and the like.

[0004] However, in the case of relay communication using regenerative relay, a delay of more than milliseconds is generated in the relay processing, so there is a problem that the coverage of ultra-low delay communication cannot be expanded. In order to solve this problem, expectations are high for non-regenerative relay that does not perform demodulation and decoding in the repeater but only performs simple processing and amplification. Therefore, non-regenerative relay communication systems such as those described in Non-Patent Documents 1 and 2 have attracted attention.

[0005] The disclosed technology of non-patent document 1 discloses non-regenerative relay communication using half-duplex communication. Also, the disclosed technology of non-patent document 2 discloses a technology in which transmission and reception use the same time slot in non-regenerative relay communication and an FIR filter is used to suppress self-interference.

[0006] Prior art literature

[0007] Non-patent literature

[0008] Non-patent document 1: H.Chen.ABGershman, and S.Shahbazpanahi, "Filter-and-Forward Distributed Beamforming in Relay Networks with Frequency SelectiveFading," IEEE Trans.On Signal Processing, vol.58, no.3, March 2010.

[0009] Non-patent document 2: Noguchi, Hayashi, Kaneko, and Sakai, “Single frequency full-duplex wireless relay for frequency domain equalization system,” Japan Institute of Electronics, Information and Communications Technology Report, vol. SIP2011-109, January 2012. Summary of the invention

[0010] Problems to be solved by the invention

[0011] However, in the disclosed technology of non-patent document 1, non-regenerative relay communication using half-duplex communication is assumed, and the same time slot is not assumed to be used for transmission and reception. Therefore, there is a problem that non-regenerative relay communication using full-duplex communication cannot be performed. In addition, in the disclosed technology of non-patent document 2, it is assumed that the relay station has multiple antennas such as array antennas and the antennas for transmission and reception are different. Therefore, there is the following problem: For example, in the case of non-regenerative relay communication using full-duplex communication, in order to reduce self-interference, different channel estimates are required for the antennas for transmission and reception.

[0012] The present invention has been developed to solve these problems, and an object of the present invention is to provide a non-regenerative relay communication system capable of performing non-regenerative relay communication using full-duplex communication.

[0013] Means for solving problems

[0014] The non-regenerative relay communication system of the first invention performs non-regenerative relay communication between a first communication station and a second communication station via a relay station, and is characterized in that the non-regenerative relay communication system comprises: a first delay calculation unit, which calculates a first signal-to-noise ratio of communication between the first communication station and the relay station and a first propagation delay representing a delay in communication between the first communication station and the relay station based on a signal sent or received in communication between the relay station and the first communication station; a second delay calculation unit, which calculates a second signal-to-noise ratio of communication between the second communication station and the relay station and a second propagation delay representing a delay in communication between the second communication station and the relay station based on a signal sent or received in communication between the relay station and the second communication station; and a communication judgment unit, which performs the non-regenerative relay communication based on the first signal-to-noise ratio and the first propagation delay calculated by the first delay calculation unit and the second signal-to-noise ratio and the second propagation delay calculated by the second delay calculation unit.

[0015] The non-regenerative relay communication system of the second invention is characterized in that, in the first invention, the non-regenerative relay communication system further comprises: a first matrix calculation unit, which calculates a first communication path matrix based on signals sent or received in the communication between more than two relay stations and the first communication station, and the first communication path matrix represents changes in communication signals caused by each communication path between more than two relay stations and the first communication station; a second matrix calculation unit, which calculates a second communication path matrix based on signals sent or received in the communication between more than two second communication stations and the first communication station, and the second communication path matrix represents changes in communication signals caused by each communication path between more than two relay stations and the first communication station. a signal-to-noise ratio calculation unit, which calculates each third signal-to-noise ratio of the communication between the first communication station and the two or more relay stations based on the first communication path matrix calculated by the first matrix calculation unit, and calculates each fourth signal-to-noise ratio of the communication between the first communication station and the two or more second communication stations based on the second communication path matrix calculated by the second matrix calculation unit; and a selection unit, which selects the second communication station and the relay station for performing the non-regenerative relay communication from the two or more relay stations and the two or more second communication stations based on each third signal-to-noise ratio and each fourth signal-to-noise ratio calculated by the noise ratio calculation unit.

[0016] The non-regenerative relay communication system of the third invention is characterized in that in the first invention, the non-regenerative relay communication system also has a processing delay calculation unit, which calculates a processing delay based on a signal sent or received in the communication between the relay station and the first communication station, and the processing delay represents a delay for processing self-interference of the communication.

[0017] The non-regenerative relay communication system of the fourth invention is characterized in that, in the third invention, the communication judgment unit calculates an allowable delay based on the first propagation delay calculated by the first delay calculation unit and the processing delay calculated by the processing delay calculation unit, the allowable delay indicating the allowable amount of delay in communication between the relay station and the second communication station, and performs 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.

[0018] The non-regenerative relay communication system of the fifth invention is characterized in that, in the fourth invention, the communication determination unit performs the non-regenerative relay communication when 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 value.

[0019] The non-regenerative relay communication system of the sixth invention is characterized in that, in the second invention, the selection unit selects the relay station whose third signal-to-noise ratio calculated by the noise ratio calculation unit is larger than a threshold value, and selects the second communication station whose fourth signal-to-noise ratio calculated by the noise ratio calculation unit is smaller than a threshold value.

[0020] Effects of the Invention

[0021] According to the first to sixth inventions, the communication determination unit performs non-regenerative relay communication based on the first signal-to-noise ratio, the first propagation delay, the second signal-to-noise ratio, and the second propagation delay. Thus, for example, the first signal-to-noise ratio, the first propagation delay, the second signal-to-noise ratio, and the second propagation delay can be calculated based on a notification signal for performing non-regenerative relay communication. Therefore, even when full-duplex communication is used, effective non-regenerative relay communication can be performed so that the cyclic prefix length is not exceeded when the relay signal is received by the second communication station.

[0022] In particular, according to the second invention, the selection unit selects the second communication station and the relay station for performing non-regenerative relay communication from among two or more relay stations and two or more second communication stations based on each third signal-to-noise ratio and each fourth signal-to-noise ratio. Thus, the signal-to-noise ratio of each line can be calculated based on the reference signal, and the relay station and the second communication station as the communication object can be selected. Therefore, more efficient non-regenerative relay communication can be performed.

[0023] In particular, according to the third invention, the processing delay calculation unit calculates the processing delay based on the signal transmitted or received in the communication between the relay station and the first communication station. Thus, for example, the processing delay can be calculated based on the reference signal. Therefore, self-interference can be suppressed even when full-duplex communication is used.

[0024] In particular, according to the fourth invention, the communication determination unit 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. As a result, it is possible to compare the allowable delay and the second propagation delay to determine whether to perform non-regenerative relay communication, thereby enabling more efficient non-regenerative relay communication.

[0025] In particular, according to the fifth invention, the communication determination unit performs non-regenerative relay communication when the calculated allowable delay is equal to or greater than the second propagation delay and the first signal-to-noise ratio and the second signal-to-noise ratio are equal to or greater than the threshold value. Therefore, even when full-duplex communication is used, effective non-regenerative relay communication can be performed so that the cyclic prefix length is not exceeded when the relay signal is received by the second communication station.

[0026] In particular, according to the sixth invention, the selection unit selects the relay station having the third signal-to-noise ratio greater than a threshold value, and selects the second communication station having the fourth signal-to-noise ratio less than a threshold value. This enables more efficient non-regenerative relay communication. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 (a) is an overall schematic diagram of a non-regenerative relay communication system when one base station is used. Figure 1 (b) is an overall schematic diagram of a non-regenerative relay communication system using a central base station and distributed base stations.

[0028] Figure 2 (a) is a schematic diagram showing an example of the structure of the control device of this embodiment, Figure 2 (b) is a schematic diagram showing an example of the function of the control device of this embodiment.

[0029] Figure 3 (a) is a schematic diagram showing an example of the structure of a relay station in the case where the number of antennas in this embodiment is one. Figure 3 (b) is a schematic diagram showing an example of the configuration of a relay station in the case where there are two antennas according to the present embodiment.

[0030] Figure 4 It is a schematic diagram showing an example of the configuration of a baseband signal processing circuit according to the present embodiment.

[0031] Figure 5 The following is a flow of processing in the non-regenerative relay communication system. DETAILED DESCRIPTION

[0032] Hereinafter, a non-regenerative relay communication system to which the present invention is applied will be described in detail with reference to the drawings.

[0033] Figure 1 (a) is an overall schematic diagram of a non-regenerative relay communication system 100 when one base station 2 is used. Figure 1 As shown in (a), the non-regenerative relay communication system 100 includes a control device 1, a base station 2 connected to the control device 1, a relay station 3 communicating with the base station 2, and a terminal station 4 communicating with the base station 2 and the relay station 3. In addition, the non-regenerative relay communication system 100 may have more than two relay stations 3 and more than two terminal stations 4.

[0034] Figure 1 (b) is an overall schematic diagram of a non-regenerative relay communication system 100 using a central base station 5 and a distributed base station 6. Figure 1As shown in (b) of FIG. 1 , the non-regenerative relay communication system 100 includes a control device 1, a central base station 5 connected to the control device 1, a distributed base station 6 communicating with the central base station 5, a relay station 3 communicating with the distributed base station 6, and a terminal station 4 communicating with the distributed base station 6 and the relay station 3. Furthermore, the non-regenerative relay communication system 100 may include more than two distributed base stations 6, more than two relay stations 3, and more than two terminal stations 4.

[0035] The control device 1 controls non-regenerative relay communication. The control device 1 may be electronic devices such as smartphones, tablet terminals, wearable terminals, IoT (Internet of Things) devices, single board computers, etc., in addition to electronic devices such as personal computers (PCs).

[0036] The base station 2 is a communication station that communicates with the terminal station 4. The base station 2 may be a first communication station BS that sends a signal to the terminal station 4, but may also be a second communication station UE that receives a signal sent from the terminal station 4. Furthermore, the base station 2 may also perform non-regenerative relay communication with the terminal station 4 via the relay station 3. The base station 2 has: a wireless device 21 for processing communication signals; a control circuit 22 connected to the wireless device 21 for controlling communication; and an antenna 23 connected to the wireless device 21 for sending and receiving signals. The base station 2 may have two or more antennas 23, such as an array antenna or the like.

[0037] The terminal station 4 is composed of a terminal device capable of wireless communication, such as a notebook personal computer (PC), a portable terminal, a smart phone, a tablet terminal, a wearable terminal, etc. The terminal station 4 may be a first communication station BS that sends a signal to the base station 2, or may be a second communication station UE that receives a signal sent from the base station 2. The terminal station 4 has: a wireless device 41 for processing communication signals; a control circuit 42 connected to the wireless device 41 for controlling communication; and an antenna 43 connected to the wireless device 41 for sending and receiving signals. The terminal station 4 may have two or more antennas 43, such as an array antenna.

[0038] The relay station 3 functions as a so-called repeater between the base station 2 and the terminal station 4, and functions as an interface with a public communication network represented by the Internet. That is, the relay station 3 is a relay unit for enabling the base station 2 and the terminal station 4 to transmit and receive data with a public communication network represented by the Internet via the relay station 3.

[0039] Next, refer to Figure 2 An example of the control device 1 according to the present embodiment will be described. Figure 2 (a) is a schematic diagram showing an example of the structure of the control device 1 of this embodiment, Figure 2 (b) is a schematic diagram showing an example of the function of the control device 1 according to the present embodiment.

[0040] For example Figure 2 As shown in (a) of FIG. 1 , the control device 1 includes 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 / Fs 105 to 107. The CPU 101, the ROM 102, the RAM 103, the storage unit 104, and the I / Fs 105 to 107 are connected via an internal bus 110.

[0041] The CPU 101 controls the control device 1 as a whole. The ROM 102 stores the action code of the CPU 101. The RAM 103 is a work area used when the CPU 101 performs an action. The storage unit 104 stores various information. For example, in addition to the HDD (Hard Disk Drive), the storage unit 104 can also use a data storage device such as an SSD (Solid State Drive), an SD card, and a miniSD card. In addition, for example, the control device 1 may also have a GPU (Graphics Processing Unit) not shown in the figure.

[0042] The I / F 105 is an interface for transmitting and receiving various information via a communication network. The I / F 106 is an interface for transmitting and receiving information with the input unit 108. As the input unit 108, for example, a keyboard is used, and a user of the control device 1 or the like inputs various information or control instructions of the control device 1 or the like via the input unit 108. The I / F 107 is an interface for transmitting and receiving various information with the display unit 109. The display unit 109 outputs various information such as specific results stored in the storage unit 104 or the processing status of the control device 1 or the like. As the display unit 109, a display is used, and for example, a touch panel type may be used.

[0043] The display unit 109 displays various information. The display unit 109 displays, for example, information on the relay station 3 performing non-regenerative relay communication.

[0044] Figure 2 (b) is a schematic diagram showing an example of the functions of the control device 1. The control device 1 includes an acquisition unit 11, a calculation unit 12, a selection unit 13, a storage unit 14, an output unit 15, and a determination unit 16. Figure 2The acquisition unit 11, calculation unit 12, selection unit 13, storage unit 14, output unit 15 and judgment unit 16 shown in (b) are implemented by the CPU 101 executing the program stored in the storage unit 104 using the RAM 103 as the working area, and can be controlled by artificial intelligence, for example.

[0045] The acquisition unit 11 acquires various information. 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 acquisition unit 11 acquires various information at any frequency and cycle.

[0046] The calculation unit 12 processes the information acquired by the acquisition unit 11. For example, the calculation unit 12 calculates the signal-to-noise ratio or propagation delay based on the information of the reference signal acquired by the acquisition unit 11. The calculation unit 12 calculates the first signal-to-noise ratio Γ of 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 a first propagation delay τ representing the delay in communication between the first communication station BS and the relay station 3 BS → Ri The calculation unit 12 calculates a second signal-to-noise ratio Γ of the communication between the second communication station UE and the relay station 3 based on a signal transmitted or received in the communication between the relay station 3 and the second communication station UE. UE → Ri and a second propagation delay τ representing the delay in communication between the second communication station UE and the relay station 3 UE → Ri The calculation unit 12 calculates the first communication path matrix H based on the signals transmitted or received in the communication between the two or more relay stations 3 and the first communication station BS. R → BS , the first communication path matrix H R → BS The calculation unit 12 calculates a second communication path matrix based on signals transmitted or received in the communication between the two or more second communication stations UE and the first communication station BS. The second communication path matrix indicates changes in communication signals based on each communication path between the two or more second communication stations UE and the first communication station BS. The calculation unit 12 calculates, for example, the first communication path matrix H calculated based on the signals transmitted or received in the communication between the two or more second communication stations UE and the first communication station BS. R → BSThe calculation unit 12 calculates the processing delay τ based on the signal transmitted or received in the communication between the relay station 3 and the first communication station BS, and calculates the fourth signal-to-noise ratio of each communication between the first communication station BS and the second communication station UE based on the calculated second communication path matrix. R,i , the processing delay τ R,i represents a delay for processing the self-interference of communication. The calculation unit 12 calculates, for example, the first propagation delay τ BS → Ri and the calculated processing delay τ R,i The calculation allows a delay of τ UE → R,max , the allowed delay τ UE → R,max Indicates the allowable amount of delay in communication between the relay station 3 and the second communication station UE.

[0047] The selection unit 13 selects the 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 selects the second communication station UE and the relay station 3 that perform non-regenerative relay communication from among two or more relay stations and two or more second communication stations UE, for example, based on each third signal-to-noise ratio and each fourth signal-to-noise ratio calculated by the calculation unit 12.

[0048] The determination unit 16 determines whether to perform non-regenerative relay communication based on the propagation delay and the signal-to-noise ratio calculated by the calculation unit 12. For example, the determination unit 16 determines whether to perform non-regenerative relay communication based on the propagation delay and the signal-to-noise ratio calculated by the calculation unit 12. BS → Ri , the first propagation delay τ BS → Ri , the second signal-to-noise ratio Γ UE → Ri and the second propagation delay τ UE → Ri To determine whether to perform non-regenerative relay communication.

[0049] The storage unit 14 retrieves various information stored in the storage unit 104 as needed. The storage unit 14 stores various information acquired or output by the acquisition unit 11, the calculation unit 12, the selection unit 13, and the determination unit 16 in the storage unit 104.

[0050] The output unit 15 outputs various information. The output unit 15 transmits a control command for non-regenerative relay communication to the base station 2 via the I / F 105, for example.

[0051] Figure 3(a) is a schematic diagram showing an example of the structure of the relay station 3 in the case where there is one antenna in this embodiment. The relay station 3 has: a wireless device 31 for processing communication signals; a control circuit 32 connected to the wireless device 31 for controlling communication; and an antenna 33 connected to the wireless device 31 for sending and receiving signals.

[0052] The wireless device 31 has a circulator 311 connected to the 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 removal circuit 312 connected to the transmitter 317 and the receiver 313.

[0053] The circulator 311 outputs a signal to the receiver 313. The isolation of the circulator 311 is about 30 dB, but is not limited thereto and can be any isolation value.

[0054] The receiver 313 is a device for receiving a signal and outputs the received signal to the ADC 314 .

[0055] The ADC 314 converts the output analog signal into a digital signal and outputs the converted digital signal to the baseband signal processing circuit 315 .

[0056] The baseband signal processing circuit 315 is a FIR (Finite Impulse Response) filter that filters the output digital signal. The baseband signal processing circuit 315 outputs the filtered signal to the control circuit 32. In addition, the baseband signal processing circuit 315 may also output the signal for suppressing self-interference output from the control circuit 32 to the DAC 316.

[0057] The DAC 316 converts the output signal into an analog signal and outputs the converted analog signal to the transmitter 317 .

[0058] The transmitter 317 up-converts the analog signal of the baseband signal, and transmits the signal via the antenna 33. Furthermore, the transmitter 317 may output a signal for suppressing self-interference to the interference removal circuit 312.

[0059] The interference removal circuit 312 is an IS (Interference suppression) circuit, and combines a signal for suppressing self-interference with a signal received by the receiver 313 to suppress self-interference.

[0060] Figure 3 (b) is a schematic diagram showing an example of the structure of the relay station 3 in the case where the number of antennas in this embodiment is two. The relay station 3 includes a wireless device 31, a control circuit 32 connected to the wireless device 31, and a plurality of antennas 33 connected to the wireless device 31. The relay station 3 may use an array antenna as the antenna 33, for example.

[0061] The wireless device 31 has 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 removal circuits 312 independently connected to each transmitter 317 and each receiver 313.

[0062] Figure 4 Schematic diagram showing an example of the configuration of the baseband signal processing circuit 315 according to this embodiment. Figure 4 In, w k,nD Indicates that for the kth (k = 1 ~ N ant ) The coefficients (complex number) of the digital filter of antenna 33, w RX,k and w TX,k represents the weight of the antenna 33 when receiving and when transmitting respectively. Also, D represents the delay unit 320. The baseband signal processing circuit 315 is, for example, a FIR (Finite Impulse Response) filter, which is a filter using a finite impulse response. The baseband signal processing circuit 315 for the kth antenna of the relay station 3 is composed of N D,k The delay 320 of the stage and the complex weight vector w k ={w k,0 ,……,w k,ND,k-1 The number of stages N of the delay unit 320 is D,k and weight w k The control circuit 32 obtains the value of the processing delay τ by optimizing the constraints set on the number of taps.R,i Furthermore, the baseband signal processing circuit 315 may also add a delay device 320 of the FIR filter to meet a given delay time Δi.

[0063] Next, use Figure 5 The processing operation of the non-regenerative relay communication system 100 is described. First, in step S1, two or more relay stations 3 as candidates for relays for non-regenerative relay communication and two or more second communication stations UE that require low-delay non-regenerative relay communication send an uplink reference signal to the first communication station BS. In this case, the first communication station BS can be the base station 2 or the terminal station 4. In addition, the second communication station UE can be the base station 2 or the terminal station 4. In step S1, the first communication station BS receives the uplink reference signal and measures the first communication path matrix H. R → BS and the second communication path matrix HUE→BS, the first communication path matrix H R → BS The second communication path matrix H represents changes in communication signals based on each communication path between two or more relay stations 3 and the first communication station BS. UE → BS , which represents the change of the communication signal based on each communication path between the first communication station BS and two or more second communication stations UE. The first communication station BS converts the first communication path matrix H R → BS and the second communication path matrix H UE → BS The communication path matrix H is a complex propagation path response. For example, if the received signal is Y R → BS , set the sending signal to X R → BS , can use Y R → BS =H R → BS X R → BS express.

[0064] Furthermore, in step S1, when the relay station 3 uses full-duplex communication, when transmitting a reference signal, the signal transmitted from the antenna enters the receiver and generates self-interference. In step S1, the relay station 3 calculates the processing delay τ based on the reference signal. R,i , the processing delay τ R,i The relay station 3 measures the self-interference based on the reference signal, sets the RF and digital filters for interference suppression, and calculates the processing delay τ. R,iThe relay station 3 uses, for example, the baseband signal processing circuit 315 to calculate the processing delay τ R,i Therefore, self-interference can be suppressed even when full-duplex communication is used.

[0065] Next, in step S2, the control device 1 calculates the first communication path matrix H notified in step S1. R → BS The control device 1 calculates the third signal-to-noise ratios of the communications between the first communication station BS and the two or more relay stations 3. In step S2, the control device 1 calculates the third signal-to-noise ratios of the communications between the first communication station BS and the two or more relay stations 3 based on the second communication path matrix H notified in step S1. UE → BS The fourth signal-to-noise ratios of the communication between the first communication station BS and the two or more second communication stations UE are calculated. In step S2, the control device 1 selects the second communication station UE and the relay station 3 for performing non-regenerative relay communication from the two or more relay stations 3 and the two or more second communication stations UE according to the third signal-to-noise ratios and the fourth signal-to-noise ratios. In this case, the control device 1 selects the relay stations 3 whose third signal-to-noise ratios are greater than the threshold value, and selects the second communication station UE whose fourth signal-to-noise ratio is less than the threshold value. For example, the control device 1 selects the second communication station UE and the relay station 3 for performing non-regenerative relay communication with low delay when the calculated fourth signal-to-noise ratio is lower than the expected value Γ for performing non-regenerative relay communication with low delay. L In the case of #j (j = 0 ~ N UE -1) as the second communication station UE as the relay object. The control device 1 calculates the third signal-to-noise ratio to be greater than the expected value Γ R =Γ L +M R In the case of #i (i = 0 ~ N R -1) as the relay target. In this case, # represents a number. R The third signal-to-noise ratio represents the margin added to the expected value. The signal-to-noise ratio is a ratio indicating the amount of noise relative to the signal. The signal-to-noise ratio may be, for example, a signal-to-noise power ratio, a signal-to-noise amplitude ratio, or the like.

[0066] Next, in step S3, the control device 1 notifies the relay station 3 of the permission of the non-regenerative relay communication and the expected signal-to-noise ratio Γ of the second communication station UE as the relay target from the first communication station BS. L,j .

[0067] Next, in step S4, the relay station 3 calculates a first signal-to-noise ratio Γ of the communication between the first communication station BS and the relay station 3 based on the notification signal notified in step S3. BS → Ri and the first propagation delay τ representing the delay in communication between the first communication station BS and the relay station 3 BS → Ri Furthermore, in step S4, the relay station 3 may also use the first propagation delay τBS → Ri and the processing delay τ calculated in step S1 R,i The calculation allows a delay of τ UE → R,max , the allowed delay τ UE → R,max represents the allowable amount of delay in communication between the relay station 3 and the second communication station UE. In this case, the allowable delay τ can be calculated using equation (1): UE → R,max .

[0068] τ UE→R,max =T CP -τ BS→R,i -τ R,i -δ (1)

[0069] In this case, T CP represents the cyclic prefix length, and δ represents the measurement deviation margin.

[0070] Furthermore, in step S4, when a relay station 3 having a plurality of antennas 33 is used as the relay station 3, the antenna weight w between the first communication station BS and the relay station 3 is adjusted according to the notification signal notified in step S3. R → BS =(w R → BS,0 ,w R → BS,1 ,……,w R → BS,Nant-1 ) is optimized and the first signal-to-noise ratio Γ is calculated BS → Ri and the first propagation delay τ BS → Ri .

[0071] Next, in step S5, the relay station 3 calculates a second signal-to-noise ratio Γ of the communication between the second communication station UE and the relay station 3 based on the reference signal. UE → Ri and a second propagation delay τ representing the delay in communication between the second communication station UE and the relay station 3 UE → Ri In this case, the i-th relay station 3 receives the uplink reference signal from the j-th second communication station UE, and calculates the second signal-to-noise ratio Γ based on the uplink reference signal. UE → Ri and the second propagation delay τ UE → Ri .

[0072] Furthermore, in step S5, when a relay station 3 having multiple antennas 33 is used as the relay station 3, the relay station 3 adjusts the antenna weight w between the second communication station UE and the relay station 3 based on the reference signal. R → UE Optimize and calculate the second signal-to-noise ratio Γ UE → Ri and the second propagation delay τ UE → Ri .

[0073] Next, in step S6, the first signal-to-noise ratio Γ calculated in step S4 is 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 To determine whether to perform non-regenerative relay communication. And, in step S6, according to the calculated allowable delay τ UE → R,max , the first signal-to-noise ratio Γ BS → Ri , the second signal-to-noise ratio Γ UE → Ri and the second propagation delay τ UE → Ri To determine whether to perform non-regenerative relay communication. In this case, the relay station 3 can calculate the allowable delay τ UE → R,max The second propagation delay τ UE → Ri Above, the first signal-to-noise ratio Γ BS → Ri and the second signal-to-noise ratio Γ UE → Ri When the value is equal to or greater than the threshold, non-regenerative relay communication is performed. For example, the relay station 3 may determine to perform non-regenerative relay communication when equation (2) is satisfied.

[0074]

[0075] In step S7, if it is determined in step S6 that non-regenerative relay communication is to be performed, non-regenerative relay communication is performed between the first communication station BS and the second communication station UE via the relay station 3. Furthermore, in step S7, when performing non-regenerative relay communication, an additional delay time Δi may be added to the relay station #i for transmission so that the signal converges to the cyclic prefix length T when the second communication station UE at the relay destination receives the signal. CP within the time.

[0076] The embodiments of the present invention have been described, but the embodiments are presented as examples and are not intended to limit the scope of the invention. Such new embodiments can be implemented in various other ways, and various omissions, substitutions, and changes can be made without departing from the scope of the main purpose of the invention. The embodiments and their variations are included in the scope and main purpose of the invention, and are included in the invention described in the claims and the scope of their equivalents.

[0077] Description of symbols

[0078] 1: control device; 2: base station; 3: relay station; 4: terminal station; 5: central base station; 6: distributed base station; 10: housing; 11: acquisition unit; 12: calculation unit; 13: selection unit; 14: storage unit; 15: output unit; 16: judgment unit; 21: wireless device; 22: control circuit; 23: antenna; 31: wireless device; 32: control circuit; 33: antenna; 41: wireless device; 42: control circuit; 43: antenna; 100: non-regenerative relay communication system; 101: CPU; 102: ROM; 103: RAM; 104: storage unit; 105: I / F; 106: I / F; 107: I / F; 108: input unit; 109: display unit; 110: internal bus; 311: circulator; 312: interference removal circuit; 313: receiver; 314: ADC; 315: baseband signal processing circuit; 316: DAC; 317: transmitter; 320: delay; BS: first communication station; UE: second communication station.

Claims

1. A non-regenerative relay communication system for performing non-regenerative relay communication between a first communication station and a second communication station via a relay station, characterized in that: The non-regenerative relay communication system comprises: a first delay calculation unit that calculates a first signal-to-noise ratio of communication between the first communication station and the relay station and a first propagation delay indicating a delay in communication between the first communication station and the relay station based on a signal transmitted or received in communication between the relay station and the first communication station; a second delay calculation unit that calculates a second signal-to-noise ratio of communication between the second communication station and the relay station and a second propagation delay indicating a delay in communication between the second communication station and the relay station based on a signal transmitted or received in communication between the relay station and the second communication station; and A communication determination unit performs the non-regenerative relay communication based on the first signal-to-noise ratio and the first propagation delay calculated by the first delay calculation unit and the second signal-to-noise ratio and the second propagation delay calculated by the second delay calculation unit.

2. The non-regenerative relay communication system according to claim 1, characterized in that: The non-regenerative relay communication system further comprises: a first matrix calculation unit that calculates a first communication path matrix based on signals transmitted or received in communication between the two or more relay stations and the first communication station, the first communication path matrix representing changes in communication signals based on each communication path between the two or more relay stations and the first communication station; a second matrix calculation unit that calculates a second communication path matrix based on signals transmitted or received in communication between the two or more second communication stations and the first communication station, the second communication path matrix representing changes in communication signals based on each communication path between the two or more second communication stations and the first communication station; a signal-to-noise ratio calculation unit, which calculates respective third signal-to-noise ratios of communications between the first communication station and the two or more relay stations based on the first communication path matrix calculated by the first matrix calculation unit, and calculates respective fourth signal-to-noise ratios of communications between the first communication station and the two or more second communication stations based on the second communication path matrix calculated by the second matrix calculation unit; as well as A selection unit selects the second communication station and the relay station for performing 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 ratios and the fourth signal-to-noise ratios calculated by the noise ratio calculation unit.

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

4. The non-regenerative relay communication system according to claim 3, characterized in that: The communication judgment unit calculates an allowable delay indicating an 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 unit and the processing delay calculated by the processing delay calculation unit, and performs 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.

5. The non-regenerative relay communication system according to claim 4, characterized in that: The communication determination unit performs the non-regenerative relay communication when the calculated allowable delay is equal to or longer than the second propagation delay and the first signal-to-noise ratio and the second signal-to-noise ratio are equal to or longer than a threshold value.

6. The non-regenerative relay communication system according to claim 2, characterized in that: The selection unit selects the relay station whose third signal-to-noise ratio calculated by the noise ratio calculation unit is larger than a threshold, and selects the second communication station whose fourth signal-to-noise ratio calculated by the noise ratio calculation unit is smaller than a threshold.

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