JP2019121995A - Relay device and relay method - Google Patents

Abstract

To relay a signal while reducing transmission capacity without degrading communication quality.SOLUTION: A relay device 3 relays a signal received from a transmission device 2 to a reception device 4. A symbol quantization unit 33 of the relay device 3 maps a reception symbol of the received signal to a region divided by a quantization threshold value on a complex plane and converts the mapped region into a quantization sign that identifies a region by a quantized value. The relay device 3 transmits the quantization sign converted by the symbol quantization unit 33 to the reception device 4.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a relay device and a relay method.

  In the communication system, a relay communication system in which communication quality is improved by using a plurality of relay devices existing between a transmitter and a receiver has been considered. FIG. 11 is a diagram showing the configuration of a relay communication system. The relay communication system includes a transmitting device, a relay device, and a receiving device. The number of relay devices in the relay communication system may be one or more arbitrary number. Among the N (N is an integer of 1 or more) relay apparatuses, the n-th relay apparatus is described as a relay apparatus #n. In the figure, the case of N = 2 is shown as an example. The connection between the transmitting device and the receiving device is a wireless connection. The connection between the relay device and the reception device may be either a wired connection or a wireless connection.

  When demodulating a received wireless signal, a real value called "Likelihood" indicating the probability that the transmitted signal bit is 0 or 1 instead of outputting the demodulation result as a 0 or 1 bit value There is a scheme called soft decision demodulation which outputs the ratio of The output of soft decision demodulation is called log likelihood ratio or LLR (see, for example, Non-Patent Document 1). In general, the value of LLR indicates that the larger the positive value, the higher the probability that the signal bit is 1, and the larger the negative value, the higher the probability that the signal bit is 0.

  Among relay communication systems, there is a regenerative quantization relay communication system that quantizes LLRs detected by a relay in communication between a transmitter and a relay and transfers the LLRs to a receiver (see, for example, Non-Patent Document 2). On the other hand, in a radio communication system, particularly in a mobile communication system, the function of the base station is set to BBU (Baseband Unit) and RRH (Remote Radio Head) in order to increase the flexibility of installation of a base station apparatus performing radio communication with terminals. It is considered to divide into two devices to be called and to have a physically separated configuration. As one of the function division methods of BBU and RRH, BBU is equipped with a function of MAC (Media Access Control) or higher, and an encoding / decoding function that is a part of physical layer functions, and encoding / decoding in RRH A function division system called SPP (Split-PHY Processing) which mounts a physical layer function other than the function is under study (see, for example, Non-Patent Document 3).

  FIG. 12 is a diagram showing a configuration of a reproduction quantization relay communication system 90 in the case where the relay device and the reception device are connected by wire. The reproduction quantization relay communication system 90 includes a transmission device 2, a relay device 8, and a reception device 9. The number of relay devices 8 is any number of one or more. The transmitting device 2, the relay device 8, and the receiving device 9 can also be regarded as terminals, RRHs, and BBUs in a mobile communication system to which the above-described SPP function division scheme is applied, respectively.

  First, the wireless reception unit 82 of each relay device 8 receives the signal transmitted from the transmission device 2 by the antenna 81. Noise is added to the received signal. Next, the demodulation unit 83 of each relay device 8 detects the LLR of the received signal by performing soft decision demodulation on the received signal. Next, the LLR quantization unit 84 performs LLR quantization, and the wired transmission unit 85 transmits the quantized LLR to the reception device 9 by wire. In the reception device 9, the wired reception unit 91 receives the LLR transmitted from the relay device, and the signal detection unit 92 determines the received bit through signal detection using the LLRs received from the plurality of relay devices 8.

  FIG. 13 is a diagram showing a configuration of a reproduction quantization relay communication system 90a in the case where the relay device and the reception device are wirelessly connected. The reproduction quantization relay communication system 90a includes a transmission device 2, a relay device 8a, and a reception device 9a. In this case, the process until the relay apparatus performs LLR quantization is the same as that of the regenerative quantization relay communication system 90 having the configuration of FIG. 12, but the quantized LLR is transmitted to the antenna 87 as a wireless signal by the wireless transmission unit 86. Are sent to the receiver 9a. The wireless reception unit 94 of the reception device 9a receives the wireless signal transmitted from the relay device 8a by the antenna 93. Thereafter, the demodulator 95 performs soft decision demodulation on the signal received by each antenna 93 to detect LLR, and thereafter, the signal detector 92 uses the LLR detected from the wireless signal of each of the plurality of relay devices 8a. The received bit is determined through detection.

  The reproduction quantization relay communication system shown in FIGS. 12 and 13 can improve the communication quality more than when the transmitting device and the receiving device directly communicate.

  The LLR quantization unit 84 of the relay devices 8 and 8a uses, for example, an arbitrary number of quantization bits to adaptively set the quantization threshold so as to minimize the BER (Bit Error Rate) according to the probability density distribution of the LLR. The quantization method which changes to is used (for example, refer nonpatent literature 2). As an example of the probability density distribution of LLR, the probability density distribution of LLRs for a QPSK (Quadrature Phase Shift Keying) signal whose signal point arrangement is represented as shown in FIG. 14 is shown in FIG. The probability density distribution of LLRs for a 16 QAM (Quadrature Amplitude Modulation) signal represented in FIG. As shown in FIG. 15, in the case of a QPSK signal, two target distributions are obtained with an LLR value of 0 as a starting point. Further, as shown in FIG. 17, in the case of a 16 QAM signal, there are four symmetrical distributions in total of two types starting from an LLR value of 0. It is known that each of these probability density distributions is Gaussian or can be approximated to a Gaussian distribution, and if the condition called the consistency condition is satisfied, the mean value and the variance value of those distributions are signal point constellations It can be derived from information and received signal to noise power ratio (SNR) (see, for example, Non-Patent Document 2).

Tomoaki Ohtsuki, "Basics and Trends of Information and Communication [III]: Error Correcting Code", Journal of the Institute of Electronics, Information and Communication Engineers, Vol. 90, No. 7, July 2007 Shinsuke Kinugasa et al., "A Study on Optimization of Quantization Threshold in Reproduction Quantization Relay Transmission", IEICE Technical Report, vol. 113, no. 456, RCS 2013-336, p. 181-186, March 2014 Kenji Miyamoto et al., "Proposal of base station function division scheme for future wireless access", IEICE Technical Report, IEICE Technical Report, vol. 115, no. 123, CS2015-15, p. 33-38 , July 2015

  In communication between the relay device and the reception device, it is necessary to transmit a data amount for the number of LLR quantization bits per information bit of 1 bit. Therefore, between the relay device and the reception device, a transmission capacity equal to the number of LLR quantization bits of the data rate between the transmission device and the reception device is required. For example, when a signal of 1 Gbps (gigabits per second) is transmitted between a transmitter and a relay, and the number of quantization bits of LLR quantization in the relay is 5 bits, the transmission capacity between the relay and the receiver is 5 Gbps It becomes. As described above, in the regenerative quantization relay communication system, there is a problem that the transmission capacity between the relay device and the receiving device increases according to the number of LLR quantization bits. On the other hand, when the communication quality between the transmitting device and the relay device is deteriorated due to, for example, reducing the number of LLR quantization bits, retransmission of data occurs between the transmitting device and the receiving device, and the relay device There is a problem that the transmission capacity between the receiving devices is further increased. Therefore, it is necessary to reduce the transmission capacity between the relay apparatus and the receiving apparatus by performing quantization with a smaller number of quantization bits while improving communication quality between the transmission apparatus and the relay apparatus of the reproduction quantization relay communication system. is there.

  Among them, in the case of the modulation scheme of 16 QAM or more, as shown in FIG. 17, the probability density distribution of LLRs becomes complicated, and the quantization design becomes complicated. Therefore, there is a problem that the signal processing delay in the relay device increases.

  In view of the above circumstances, the present invention has an object to provide a relay apparatus and a relay method capable of relaying a signal with a reduced transmission capacity without reducing communication quality.

  One aspect of the present invention is a relay apparatus for relaying a received signal, wherein received symbols of the received signal are mapped in a region separated by a quantization threshold on a complex plane, and the mapped region is And a symbol quantization unit configured to convert the region into a quantization symbol that specifies the region according to a quantized value.

  One embodiment of the present invention is the above-mentioned relay apparatus, wherein the symbol quantization unit performs modulo operation when the received symbol is mapped out of a basic region which is a defined region on a complex plane. Based on the received symbol, the mapping to the basic area comprising a coset leader is performed.

  One embodiment of the present invention is the above-mentioned relay apparatus, wherein the symbol quantization unit is configured to transmit the part or all of the received symbols with the number of quantization bits different from the number of quantization bits of the received symbols. Convert to a symbol.

  One embodiment of the present invention is the above-mentioned relay apparatus, wherein the symbol quantization unit adapts the quantization threshold in the area to which a part or all of the received symbols are mapped according to a channel condition. Control.

  One embodiment of the present invention is the above-described relay device, wherein the relay device includes a receiving unit that receives the signal by Multiple Input Multiple Output (MIMO) transmission.

  One embodiment of the present invention is the above-described relay device, further comprising: a transmission unit that transmits a signal in which the quantization symbol converted by the symbol quantization unit is set to a relay destination device.

  One aspect of the present invention is a relay method executed by a relay apparatus that relays a received signal, wherein the received symbols of the received signal are mapped on a region separated by a quantization threshold on a complex plane, and the mapping is performed. And a symbol quantization step of converting the determined region into a quantization symbol that specifies the region by a quantized value.

  According to the present invention, it is possible to reduce the transmission capacity and relay signals without reducing the communication quality.

It is a figure which shows the structure of the reproduction | regeneration quantization relay communication system by the 1st Embodiment of this invention. It is a figure which shows the other structure of the reproduction | regeneration quantization relay communication system by the embodiment. It is a figure which shows the example of the symbol quantization by the embodiment. It is a figure which shows the example of symbol conversion by the embodiment. It is a figure which shows the example of 6 bit quantization in 16 QAM by 2nd Embodiment. It is a figure which shows the example of 8-bit quantization in 16 QAM by the embodiment. It is a figure which shows the example of the irregular quantization threshold value by 3rd Embodiment. It is a figure which shows the other example of the non-regular quantization threshold value by the embodiment. It is a figure which shows the structure of the reproduction | regeneration quantization relay communication system by 4th Embodiment. It is a figure which shows the other structure of the reproduction | regeneration quantization relay communication system by the embodiment. It is a figure which shows the structure of the relay communication system by a prior art. It is a figure which shows the structure of the reproduction | regeneration quantization relay communication system by a prior art. It is a figure which shows the other structure of the reproduction | regeneration quantization relay communication system by a prior art. It is a figure which shows the signal point arrangement | positioning of a QPSK signal. FIG. 7 is a diagram showing a probability density distribution of LLRs for a QPSK signal. It is a figure which shows the signal point arrangement | positioning of a 16 QAM signal. FIG. 6 is a diagram showing a probability density distribution of LLRs for a 16 QAM signal.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. The present embodiment relates to a relay apparatus and a relay method for improving communication quality in a receiving apparatus by relaying a signal from a transmitting apparatus. In this embodiment, in a relay communication system that performs multi-level modulation such as 16 QAM, quantization is performed not on LLRs after soft demodulation of received symbols but on received symbols themselves in the relay apparatus. Generalize and simplify the design.

First Embodiment
FIG. 1 is a diagram showing the configuration of a regenerative quantization relay communication system 1 according to the first embodiment. The reproduction quantization relay communication system 1 includes a transmission device 2, a relay device 3, and a reception device 4. The number of relay devices 3 included in the regenerative quantization relay communication system 1 is an arbitrary number of two or more. In the figure, the case where the reproduction | regeneration quantization relay communication system 1 is equipped with two relay apparatuses 3 is shown as an example.

  The relay device 3 includes an antenna 31, a wireless reception unit 32, a symbol quantization unit 33, and a wired transmission unit 34. The antenna 31, the wireless reception unit 32, the symbol quantization unit 33, and the wired transmission unit 34 have the same functions as the antenna 81, the wireless reception unit 82, and the wired transmission unit 85 of the conventional relay device 8 shown in FIG.

  The wireless reception unit 32 receives the signal transmitted from the transmission device 2 by the antenna 31. The symbol quantizing unit 33 maps the received symbols of the received signal to the area divided by the quantization threshold on the complex plane, and converts the mapped area into a quantized symbol. A quantization symbol is information identifying a region by a quantized value. The wired transmission unit 34 transmits a signal in which the quantization symbol is set to the receiving device 4 by wire.

  The reception device 4 includes a wired reception unit 41 and a signal detection unit 42. The receiving device 4 includes a plurality of wired receiving units 41 corresponding in number to the relay device 3. The wired receiver 41 has the same function as the wired receiver 91 of the conventional receiving apparatus 9 shown in FIG. The wired reception unit 41 receives the signal transmitted from the relay device 3 by wire. The signal detection unit 42 determines the received bit through signal detection using the quantization symbol set in the signals received from the plurality of relay devices 3.

  In the regenerative quantization relay communication system 1 shown in FIG. 1, although the relay device and the receiver are wired, they may be wirelessly connected as shown in FIG. FIG. 2 is a diagram showing the configuration of the regenerative quantization relay communication system 1a of the present embodiment. In the figure, the same parts as in the regenerative quantization relay communication system 1 shown in FIG. The reproduction quantization relay communication system 1a has a relay device 3a and a reception device 4a instead of the relay device 3 and the reception device 4 included in the reproduction quantization relay communication system 1 shown in FIG.

  The relay device 3a differs from the relay device 3 shown in FIG. 1 in that the relay device 3a includes a wireless transmission unit 35 and an antenna 36 instead of the wired transmission unit 34. The wireless transmission unit 35 and the antenna 36 have the same functions as the wireless transmission unit 86 and the antenna 87 included in the conventional relay device 8 shown in FIG. The wireless transmission unit 35 wirelessly transmits the signal in which the quantization symbol is set from the antenna 36.

  The receiving device 4a differs from the receiving device 4 illustrated in FIG. 1 in that the receiving device 4a includes an antenna 43, a wireless receiving unit 44, and a demodulating unit 45 instead of the wired receiving unit 41. The receiving device 4a includes a plurality of sets of the antenna 43, the wireless receiving unit 44, and the demodulating unit 45. Each set corresponds to one relay device 3a. The antenna 43, the wireless reception unit 44, and the demodulation unit 45 have the same functions as the antenna 93, the wireless reception unit 94, and the demodulation unit 95 provided in the conventional reception device 9a shown in FIG. The wireless reception unit 44 receives the signal wirelessly transmitted from the relay device 3 a by the antenna 43. The demodulation unit 45 performs soft decision demodulation on the signal received by the wireless reception unit 44 to detect a quantization symbol.

  In addition, between the relay device 3a and the reception device 4a, MIMO (Multiple-Input Multiple-Output) transmission using a plurality of antennas may be performed as wireless communication. Further, in this case, when the wireless band between the relay apparatus 3a and the receiving apparatus 4a is limited by the wireless propagation environment, the quantization threshold may be set in the symbol quantization unit 33 according to the limitation. Hereinafter, an embodiment in which 16 QAM is used for wireless transmission between the transmitter 2 and the relay 3 and 3a and the number of quantization bits is 2 will be described.

  The symbol quantization unit 33 of the relay device 3 or 3a represents the received symbol of the signal received from the transmission device 2 by the 0 to 15 quantization symbols corresponding to the 16 square areas represented by 2 bits. To perform quantization. An example of quantization by the symbol quantization unit 33 will be described with reference to FIG.

  FIG. 3 is a diagram showing an example of symbol quantization in 4-bit quantization of 16 QAM. In the figure, 16 square areas centered on each signal point of 16 QAM are arranged on the IQ plane so as to be in contact with each other. In the figure, each side of each square is parallel to one of the I and Q axes and perpendicular to the other. Each square area is identified by a quantization symbol of 0 to 15, respectively. For example, the quantization symbol of the reception symbol R1 in the same figure is "15". Each side of the square region represents a quantization threshold when converting the received symbol to a quantization symbol.

  The received symbols may be received in areas other than the 16 squares shown in FIG. In this case, the symbol quantization unit 33 performs received symbol conversion.

  FIG. 4 is a diagram showing an example of received symbol conversion. R2 shown in the figure is an actual received symbol. Assuming that the region of 16 squares shown in FIG. 3 is a basic region, the received symbol R2 is a region other than the basic region. In order to generalize such received symbols outside the basic region, the symbol quantization unit 33 first performs scaling and shift on the Euclidean space of the complex plane that can be taken by the received symbols, and a lattice space composed of integer grids. Form Furthermore, the symbol quantization unit 33 performs modulo arithmetic on the integer axes of the real axis and the imaginary axis, and maps the coset to the coset leader of the basic region. At this time, the actual received symbol R 2 in the same figure is converted to the received symbol R 2 ′ in the area of the quantization symbol 12.

  The symbol quantization unit 33 assumes that the same square basic area exists around the basic area consisting of 16 squares in this way, and the symbol received outside the basic area is indicated by a solid line. Convert to corresponding quantized symbols in the basic domain of 16 coset leaders. This means that only sixteen square regions need to be considered, including symbols received outside the basic region. The relay device 3 transmits the quantization symbol obtained by the symbol quantization unit 33 to the reception device 4 by wire or wirelessly.

Next, the signal detection unit 42 of the receiver 4 or 4 a estimates transmission symbols. A quantization symbol vector q representing a quantization symbol observed in the signal detection unit 42 is represented by the following equation (1). q _n is a quantization symbol obtained from the signal received from the relay device #n.

  Assuming that a is a transmission symbol, the posterior probability P [a | q] is expressed as in the following equation (2) using Bayesian theorem.

  When q is observed, the signal detection unit 42 calculates Equation (2) for all 16 transmission symbols in 16 QAM, and estimates the transmission symbol with the largest posterior probability as in the following Equation (3). Signal detection is performed.

The calculation of P [q ₁ | a] and P [q ₂ | a] can be obtained by marginalizing the probability over the 16 regions shown in FIG. 3. By performing received symbol conversion based on the modulo operation shown in FIG. 4, the marginalization of this probability can be simplified. Specifically, in the case where reception symbol conversion is not performed in FIG. 4, it is necessary to perform probability marginalization for 144 regions including the broken line region, but by performing reception symbol conversion, solid line 16 It is only necessary to marginalize the probability for each region.

Second Embodiment
In the present embodiment, the number of quantization bits of the quantization symbol in the first embodiment is increased.

  FIG. 5 is a diagram showing an example of 6-bit quantization in 16 QAM. In 6-bit quantization, one square area in FIG. 3 is divided into four square areas with each side having a half length. In the case of 6-bit quantization, the number of quantization symbols is 64 in total from 0 to 63, and the signal space is divided into 64 squares.

  FIG. 6 is a diagram showing an example of 8-bit quantization in 16 QAM. In 8-bit quantization, one square area in FIG. 3 is divided into 16 square areas with each side having a length of 1⁄4. In the case of 8-bit quantization, the signal space is divided into 256 pieces, and the quantization symbols are also 256 pieces represented by 8 bits.

  Even with 6-bit or 8-bit quantization, received symbol conversion based on coset can be performed as in the first embodiment, and signal detection can also be performed as in the first embodiment.

  In the above, all the square areas shown in FIG. 3 or 4 are divided into four or nine, but only some areas may be divided. As described above, the symbol quantization unit 33 may convert some or all of the received symbols into quantized symbols having the number of quantization bits different from the number of quantization bits of the received symbol.

Third Embodiment
In the present embodiment, the quantization threshold in the first embodiment is set to be non-regular.

  FIG. 7 is a diagram showing an example of the non-singular quantization threshold in 16 QAM. The symbol quantization unit 33 can also perform quantization with a threshold as shown by a dotted line in FIG. 7 by shifting the grid in FIG. As a threshold design, for example, as shown in FIG. 7, the length of one side of a square surrounding a signal point may be changed as η.

  FIG. 8 is a diagram showing another example of the non-smooth quantization threshold. As shown to the same figure, you may apply the threshold value design using not a square but a circle. At this time, a quantization symbol is assigned to each of the regions divided into four by a circle and its periphery in a square.

The third embodiment and the second embodiment may be combined. The optimum η depends on the received SNRγ of each RRH, and the criterion for minimizing the symbol error rate 式 of equation (4) based on equation (2) or, for example, in equation (5) in 6-bit quantization The mutual information amount I _in is selected according to the maximization criterion. Here, a ^ in equation (4) represents the estimated transmission symbol, and q _{a ^} represents one realization value of the set of belts q determined to be a ^. Further, N in the equation (5) represents the number of quantization symbols, and Q represents the modulation multi-level number. In addition, on the premise of using adaptive coding modulation, the threshold を may be adjusted so that a higher transmission rate MCS (Modulation and Coding Scheme) can be selected while satisfying a predetermined communication quality.

  As described above, the symbol quantization unit 33 partially or entirely to minimize the symbol error rate or maximize the mutual information amount based on the above equation (4) or (5). The quantization threshold in the region to which the received symbol of S is mapped may be adaptively controlled according to the channel condition.

Fourth Embodiment
In the fourth embodiment, MIMO (Multiple Input Multiple Output) transmission using a plurality of antennas is applied to the wireless section between the transmitter and the relay in the first embodiment.

  FIG. 9 is a diagram showing the configuration of the reproduction quantization relay communication system 10 of the present embodiment. In the figure, the same parts as those of the regenerative quantization relay communication system 1 according to the first embodiment shown in FIG. 1 are designated by the same reference numerals, and the description thereof will be omitted. The reproduction quantization relay communication system 10 has a transmission device 20 and a relay device 30 instead of the transmission device 2 and the relay device 3 included in the reproduction quantization relay communication system 1 shown in FIG.

  The transmission device 20 transmits a radio signal to the relay device 30 by MIMO transmission using a plurality of antennas. The relay device 30 includes a plurality of antennas 31, a plurality of wireless reception units 32, a MIMO equalization unit 37, a symbol quantization unit 33, and a wired transmission unit 34. The wireless reception unit 32 receives signals transmitted by radio from each antenna of the transmission device 20 by the antenna 31. The MIMO equalization unit 37 detects received symbols of the signal stream received by the plurality of antennas 31.

  In the regenerative quantization relay communication system 10 shown in FIG. 9, although the relay device and the receiver are wired, they may be wirelessly connected as shown in FIG. FIG. 10 is a diagram showing the configuration of the reproduction quantization relay communication system 10a of the present embodiment. In the figure, the same parts as those of the reproduction quantization relay communication system 1a shown in FIG. 2 or the reproduction quantization relay communication system 10 shown in FIG.

  The reproduction quantization relay communication system 10a has a relay device 30a and a reception device 4a instead of the relay device 30 and the reception device 4 of the reproduction quantization relay communication system 10 shown in FIG. The relay device 30a is different from the relay device 30 shown in FIG. 9 in that the relay device 30a includes a wireless transmission unit 35 and an antenna 36 instead of the wired transmission unit 34.

  Note that, between the relay device 30a and the reception device 4a, MIMO transmission using a plurality of antennas may be performed as wireless communication. Also, in this case, when the wireless band between the relay device 30a and the receiving device 4a is limited by the wireless propagation environment, the quantization threshold is set in the symbol quantization unit 33 of the relay device 30a according to the limitation. It is also good.

  In the present embodiment, the MIMO equalization unit 37 of each of the relay devices 30 and 30 a detects received symbols of the signal stream received by the plurality of antennas 31. At this time, there may be a plurality of signal streams to be MIMO transmitted. After the MIMO equalization unit 37 converts to lattice space as orthogonal as possible based on lattice reduction, the symbol quantizing unit 33 of each of the relay devices 30 and 30a performs the first to third embodiments. Perform quantization similar to the form. The same quantization as in the first to third embodiments may be performed on received symbols subjected to spatial filtering such as zero forcing (ZF) and minimum mean squared error (MMSE).

  According to the embodiment described above, the relay device includes the symbol quantization unit. The symbol quantizing unit maps received symbols of the signal received from the transmitter to regions separated by a quantization threshold on the complex plane, and quantizes the mapped regions by the quantized values. Convert to a symbol. When the received symbol is mapped out of the basic area which is a defined area on the complex plane, the symbol quantizing unit maps the received symbol to the basic area consisting of the coset leader based on the modulo operation. Do. The symbol quantizing unit may convert some or all of the received symbols into quantized symbols of the number of quantization bits different from the number of quantization bits of the received symbol. Also, the symbol quantization unit may adaptively control the quantization threshold in the region to which some or all of the received symbols are mapped, in accordance with the channel condition. The transmission unit of the relay device transmits the signal in which the quantization symbol converted by the symbol quantization unit is set to the reception device of the relay destination. The transmission unit corresponds to, for example, the wired transmission unit 34 or the wireless transmission unit 35 in the embodiment.

  According to the above-described embodiment, it is possible to simplify the quantization design in the relay apparatus and to reduce the signal processing delay of the quantization.

  Some of the functions of the relay device and the receiving device described above may be realized using hardware such as an application specific integrated circuit (ASIC), a programmable logic device (PLD), or a field programmable gate array (FPGA). In addition, the relay device and the reception device may include a CPU (Central Processing Unit), a memory, an auxiliary storage device, and the like connected by a bus, and may execute part of the functions described above by executing a program. The program may be recorded on a computer readable recording medium. The computer readable recording medium is, for example, a portable medium such as a flexible disk, a magneto-optical disk, a ROM, a CD-ROM, or a storage device such as a hard disk built in a computer system. The program may be transmitted via a telecommunication link.

  The embodiment of the present invention has been described in detail with reference to the drawings. However, the specific configuration is not limited to this embodiment, and includes design and the like within the scope of the present invention.

  It is applicable to the apparatus which relays a signal.

DESCRIPTION OF SYMBOLS 1, 1a, 10, 10a ... Reproduction | requirement quantization relay communication system, 2, 20 ... Transmission apparatus, 3, 3a, 30, 30a ... Relay apparatus, 4, 4a ... Reception apparatus, 31, 36, 43 ... Antenna, 32, 44 wireless reception unit 33 symbol quantization unit 34 wired transmission unit 35 wireless transmission unit 37 MIMO equalization unit 41 wired reception unit 42 signal detection unit 45 demodulation unit

Claims (7)

A relay device that relays a received signal, and
A symbol for mapping a received symbol of the received signal to a region separated by a quantization threshold on a complex plane, and converting the mapped region into a quantization symbol specifying the region by a quantized value Quantizer,
A relay device provided with The symbol quantizing unit is configured to include the coset leader with respect to the received symbol based on a modulo operation when the received symbol is mapped out of a basic region that is a defined region on a complex plane. Do the mapping to
The relay device according to claim 1. The symbol quantization unit converts some or all of the received symbols into the quantized symbols of which the number of quantization bits is different from the number of quantization bits of the received symbols.
The relay device according to claim 1 or 2. The symbol quantization unit adaptively controls the quantization threshold in the area to which some or all of the received symbols are mapped, according to a channel condition.
The relay device according to any one of claims 1 to 3. The relay apparatus includes a receiving unit that receives the signal by Multiple Input Multiple Output (MIMO) transmission.
The relay device according to any one of claims 1 to 4. The signal processing apparatus further comprises a transmission unit that transmits the signal in which the quantization symbol converted by the symbol quantization unit is set to a relay destination apparatus.
The relay device according to any one of claims 1 to 5. A relay method performed by a relay apparatus that relays a received signal, the relay method comprising:
A symbol for mapping a received symbol of the received signal to a region separated by a quantization threshold on a complex plane, and converting the mapped region into a quantization symbol specifying the region by a quantized value Quantization step,
A relay method having

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