JP2012005046A - Communication system, relay unit, and communication method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a communication system capable of achieving a high-performance transmission.SOLUTION: A communication system has a BS (Base Station), a MS (Mobile Station), and two or more AFs (Amplifier and Forward) that relay the communication between the BS and the MS. The BS encodes transmission signals S1 and S2 by time-spatial block encoding or frequency space block encoding, and transmits the encoded signals from two transmission antennas. The AF has reception antennas 21-1 and 21-2, transmission antennas 24-1 and 24-2, and a signal processing part 22 that carries out a predetermined process to a received transmission signal to generate a relay transmission signal to be transmitted from the transmission antennas 24-1 and 24-2. The signal processing part 22 uses a transmission signal matrix representing the relay transmission signal to be transmitted from the two or more AFs to the MS as an orthogonal matrix, and carries out the predetermined process so that each element in the transmission signal matrix includes only S1 or S2.

Description

  The present invention relates to a communication system in which MIMO (Multiple Input Multiple Output) transmission is performed.

  The demand for high speed and large capacity in wireless broadband is increasing day by day. Under such circumstances, in order to dramatically improve the transmission capacity, a MIMO transmission system has been introduced in mobile communication, wireless LAN (Local Area Network) and the like. Further, MIMO-OFDM / OFDM / OFDMA (Orthogonal Frequency Division Multiplexing / Orthogonal Frequency Division Multiple Access) scheme combined with the above MIMO transmission scheme is characterized by flexible resource control and strong resistance to frequency selective fading. In recent years, studies on the MIMO-OFDMA scheme have been rapidly advanced. In the OFDM / OFDMA scheme, the entire system band is divided into a plurality of frequency blocks, and data is assigned to each block.

  MIMO transmission is classified into two communication methods. One is a communication method in which the number of transmission signals is larger than the number of used radio resources, and the transmission rate can be improved efficiently. The other is a communication method for performing transmission called Rate = 1, in which the number of transmission signals is equal to or less than the number of used radio resources. Taking advantage of the multi-antenna transmission, space-time diversity is achieved. Obtainable.

  In such a background, a SICC (Self-Interference Cancellation Coding) transmission scheme is proposed in Patent Document 1 below as a robust MIMO transmission scheme in continuous signal transmission or HARQ (Hybrid Automatic Repeat reQuest). The SICC method can be applied as a rate-1 MIMO signal transmission capable of self-interference or a HARQ transmission method, and can eliminate self-interference, so its performance improvement capability is large compared to the conventional method Chase Combining .

International Publication No. 2009/084207

  According to the conventional SICC transmission technique, the transmitter needs to have transmission antennas corresponding to the number of spatial diversity orders realized between the transmitter and the receiver. Therefore, if the space diversity order is increased in order to realize high-performance transmission, the cost increases with the increase in the number of transmitting antenna installation spaces and the number of RF (Radio Frequency) ports, resulting in a low-cost and high-performance SICC transmission method. There was a problem that it was difficult to realize.

  The present invention has been made in view of the above, and an object of the present invention is to obtain a communication system, a relay device, and a communication method capable of realizing high-performance transmission while suppressing an increase in the number of transmission antennas.

  In order to solve the above-described problems and achieve the object, the present invention includes a transmitter, a receiver, and two or more relay devices that relay communication between the transmitter and the receiver. The transmitter generates two or more transmission antennas and a divided transmission signal obtained by dividing the transmission signal into the number of the transmission antennas, and the divided transmission signal is subjected to space-time block coding or frequency. A data division unit that performs space block coding and outputs the result as a blocked signal to the transmission antenna, and the relay unit includes one or more relay reception antennas, one or more relay transmission antennas, and the relay reception. A signal processing unit that generates a relay transmission signal to be transmitted from the relay transmission antenna by performing predetermined processing on the blocked signal received from the antenna, and The processing unit uses a transmission signal matrix representing the relay transmission signal transmitted from the two or more relay apparatuses to the receiver as an orthogonal matrix, and each of the elements of the transmission signal matrix includes the single divided transmission signal. The predetermined processing is performed so as to include it.

  According to the present invention, there is an effect that high-performance transmission can be realized while suppressing an increase in the number of transmission antennas.

FIG. 1 is a diagram illustrating a configuration example of a communication system according to the first embodiment. FIG. 2 is a diagram illustrating a functional configuration example of a transmitter included in the BS. FIG. 3 is a diagram illustrating a functional configuration example of AF. FIG. 4 is a diagram illustrating a configuration example of a communication system according to the second embodiment.

  Embodiments of a communication system, a repeater, and a communication method according to the present invention will be described below in detail with reference to the drawings. Note that the present invention is not limited to the embodiments.

Embodiment 1 FIG.
FIG. 1 is a diagram illustrating a configuration example of a communication system according to a first embodiment of the present invention. As shown in FIG. 1, the communication system according to the present embodiment includes a BS (Base Station) 1 that functions as a transmitter according to the present embodiment, and an AF (Amplifier and AF) that is a relay that relays signals transmitted from BS1. Forward) 2-1 and 2-2 and MS (Mobile Station) 3 that is a receiver that receives a signal transmitted from BS 1 relayed by AF 2-1 and 2-2. In this embodiment, the transmitter is a base station (BS) and the receiver is a mobile station (MS). However, the transmitter is not limited to a base station, and the receiver is not limited to a mobile station.

  As shown in FIG. 1, the BS 1 includes two transmission antennas, and can transmit different signals from each transmission antenna. In this embodiment, the case where the BS 1 includes two transmission antennas will be described, but the number of transmission antennas may be three or more.

  Each of the AFs 2-1 and 2-2 includes two transmission antennas and two reception antennas. In addition, although the example of a transmitting antenna and a receiving antenna is demonstrated here, the number of the transmitting antennas and receiving antennas with which AF2-1 and 2-2 are provided may be three or more.

  The MS 3 includes one receiving antenna, performs a predetermined demodulation process on the received signal, and acquires transmitted data. In this embodiment, the number of receiving antennas provided in the MS 3 is one, but it may be two or more.

  FIG. 2 is a diagram illustrating a functional configuration example of the transmitter 10 included in the BS 1. The transmitter 10 includes an FEC (Forward Error Correction) encoding unit 11, a modulation unit 12, a data distribution unit 13, resource mapping units 14-1 and 14-2, and baseband / RF processing units 15-1 and 15. -2 and transmission antennas 16-1 and 16-2.

  The FEC encoding unit 11 is defined by the communication system of the present embodiment (for use in the communication system of the present embodiment) for user data that is data input from a higher-level device or the like via a core network, for example. FEC encoding is performed based on the FEC type (which is defined in advance), and the encoding result is output to the modulation unit 12 as an FEC block.

  The modulation unit 12 generates modulation data mapped to the signal constellation by performing primary modulation at the MCSM (Modulation and Coding Scheme) level defined in the communication system of the present embodiment on the FEC block. And output to the data distributor 13.

  The data distribution unit 13 performs serial-parallel conversion on the modulated data in accordance with a method defined by the communication system according to the present embodiment to generate a plurality of modulated data (transmission streams). Here, since the transmitter 10 has two transmission antennas, the data distribution unit 13 generates two modulated data, one to the resource mapping unit 14-1 and the other to the resource mapping unit 14-2. , Respectively.

  The resource mapping unit 14-m (m = 1, 2) allocates (maps) the input modulation data to the radio lease, and maps the modulation data (mapping data) to the baseband / RF processing unit 15-m. Output to. Any mapping method may be used. For example, when OFDM / OFDMA transmission is used, modulation data is continuously allocated to radio resource regions that are continuous in the frequency direction and the time direction. Allocation methods are commonly used.

  The baseband / RF processing unit 15-m performs predetermined radio signal processing on the input mapping data, converts the processed signal into an RF band, and transmits it to the space as an antenna via the transmission antenna 16-m. Radiate. For example, in the case of the OFDM / OFDMA transmission system, as this predetermined radio signal processing, mapping data is converted from a frequency axis signal to a time axis signal by IFFT conversion, and a GI (Guard Interval) signal is added. Processing is performed.

  When the number of transmission antennas of BS1 is three or more, the data distribution unit 13 generates modulation data (transmission stream) for the number of transmission antennas, and transmits the resource mapping unit and the baseband / RF processing unit. Prepare for each antenna.

  FIG. 3 is a diagram illustrating a functional configuration example of the repeater 20 included in the AFs 2-1 and 2-2 of the present embodiment. As shown in FIG. 3, the repeaters 20 included in the AFs 2-1 and 2-2 include reception antennas (relay reception antennas) 21-1 and 21-2, a signal processing unit 22, and a power amplification unit 23-, respectively. 1 and 23-2 and transmission antennas (relay transmission antennas) 24-1 and 24-2.

  In AF 2-1 and 2-2, the signal processing unit 22 generates two transmission signals by performing predetermined analog signal processing on the reception signals received by the reception antennas 21-1 and 21-2. Then, the power amplifying unit 23-m (m = 1, 2) power-amplifies the two signals generated by the signal processing unit 22, and radiates the power-amplified signals to the antennas via the transmitting antenna 24-m. To do.

  In the configuration example of FIG. 3, power amplification and analog signal processing are performed without performing frequency conversion on an RF (Radio Frequency) signal that is a received signal, but the RF signal is down-converted. Alternatively, the signal may be converted into an IF signal or a baseband signal, and power amplification and analog signal processing may be performed on the converted signal. In addition, the AF 2-1 and 2-2 do not demodulate the modulation signal, but the signal input to the signal processing unit 22 is converted into a digital signal by an AD (Analog-Digital) converter, and the signal processing unit 22 receives the signal. Predetermined signal processing may be performed on the digital signal.

  Next, the operation of the present embodiment will be described. In BS1 of the present embodiment, data distribution unit 13 generates transmission signals to be transmitted from transmission antennas 16-1 and 16-2, respectively. The baseband representation of the transmission signal transmitted by BS1 of the present embodiment is shown as a transmission signal matrix in the following equation (1).

Here, in the matrix S (bold) _BS in the above formula (1), the row direction is a transmission antenna number (for example, m of the transmission antenna 16-m is a transmission antenna number), and the column direction is on the time axis. When a transmission signal symbol is assigned to a signal, a time direction in units of a transmission symbol may be used, or a frequency direction (subcarrier number) may be used when OFDMA / OFDM transmission is used. Hereinafter, the column direction is referred to as a transmission signal symbol direction. ^* Represents a complex conjugate. Since the above equation (1) is an equivalent low-frequency system of the baseband signal, S _i is a signal constellation symbol corresponding to the modulation degree that is primarily modulated by the modulation unit 12. i is a transmission signal constellation symbol number.

In the present embodiment, BS1 uses space time block coding (STBC) or space frequency block coding (SFBC) as shown in the above equation (1), L (L columns) parallel transmission signals are generated based on L transmission symbols. Here, L = 2, and based on the _two transmission symbols S ₁ and S ₂ , a parallel transmission signal as shown in the matrix S (bold) _BS in the above equation (1) is generated. When the number of transmission antennas included in BS1 is three or more (L), similarly, L parallel transmission signals are generated based on L transmission symbols using STBC or SFBC.

  Signals transmitted from BS1 are received by AFs 2-1 and 2-2, respectively. The channel matrix (transmission path matrix) between BS1 and AF2-1, 2-2 can be expressed by the following equation (2).

H (bold) ₁ represents a channel matrix from BS1 to AF2-1, and H (bold) ₂ represents a channel matrix from BS1 to AF2-2. In addition, h 1 — _ij in the matrix H (bold) ₁ is a channel coefficient from the j-th transmission antenna of BS1 to the i-th reception antenna of _AF2-1 , and h _{2 — ij} in the matrix H (bold) ₂ is BS1. Is the transmission line coefficient from the j-th transmitting antenna to the i-th receiving antenna of AF2-2.

  From the above equations (1) and (2), the received signals received by the AFs 2-1 and 2-2 are expressed by the following equation (3).

Here, R (bold) _i represents a received signal matrix of AF2-i, the row direction of R (bold) _i represents a reception antenna number, and the column direction represents a transmission symbol direction. _Further, r i_j ^(k) denotes the k-th received symbol of the receiving antenna 21-j of AF2-i (e.g. OFDMA symbol).

Next, signal processing performed by the signal processing units 22 of AFs 2-1 and 2-2 shown in FIG. 3 will be described. In AF 2-1 and 2-2, the signal processing unit 22 performs signal processing on the received signal to generate transmission signals to be transmitted from the transmission antennas 24-1 and 24-2. Transmit from 24-2. In BS1, as shown in (1) above, retransmission is performed twice in the transmission symbol direction (information including S ₁ and S ₂ is transmitted twice or at two frequencies, respectively). In 1 and 2-2, the number of retransmissions is four. The transmission signal transmitted from the AF2-1 antenna 24-1 can be expressed by the following equation (4).

_{Incidentally,} w i_j ^{(k) (),} to the signal processing unit 22 receives signals, the signal processing function showing processing performed to generate the k-th symbol to be transmitted from the transmitting antenna 24-j of AF2-i It is.

  Similarly, the transmission signal transmitted from the antenna 24-2 of AF2-1 is expressed by the following equation (5), and the transmission signal transmitted from the antenna 24-1 of AF2-2 is expressed by the following equation (6): AF2-1. The transmission signal transmitted from the antenna 24-2 can be expressed by the following equation (7).

  Since the first transmission signal generated by the signal processing performed by the signal processing unit 22 uses the signal transmitted as the transmission signal of the second transmission from BS1, 1 in the above formulas (4) to (7) is used. The transmission signal is generated after receiving the second transmission symbol of BS1, but the transmission signals after the second transmission in the above formulas (4) to (7) are also the second transmission symbol of BS1. It can be generated from the time of reception.

  When the above equations (4) to (7) are expressed as transmission signal matrices of all AFs (AF2-1 and AF2-2), equation (8) is obtained.

Here, the transmission signal matrix S of all AFs (bold) The row direction of _AF corresponds to the numbers of the transmission antennas of AF2-1 and 2-2, and the first and second rows are the transmission antennas of AF2-1. It corresponds to 24-1 and 24-2, respectively, and the third and fourth rows correspond to the transmission antennas 24-1 and 24-2 of AF2-2, respectively. The column direction is the transmission signal symbol direction.

As can be seen from Expression (8), the transmission signal matrix S (bold) _AF of all _AFs is an orthogonal matrix. In other words, in the present embodiment, w _{i — j} ^(k) () is determined so that the transmission signal matrix S (bold) _AF of all _AFs becomes an orthogonal matrix as shown in Expression (8). As shown in Expression (8), each element of the transmission signal matrix S (bold) _AF of all AFs includes only S ₁ or S ₂ (elements including both S ₁ and S ₂ are No). Therefore, a function for decoding S (bold) _BS (a function for separating S ₁ and S ₂ ) can be used as w _{i — j} ^(k) (). In summary, w _{i — j} ^(k) () is a function for separating S ₁ and S ₂ , and any function may be used as long as the transmission signal matrix S (bold) _{AF of} all _AFs is an orthogonal matrix. . w _{i — — j} ^(k) () is not limited to the functions shown in the above equations (4) to (7), and any function may be used as long as it satisfies such conditions.

  Next, the reception process of the MS 3 will be described. The channel matrix from AF2-1, 2-2 to MS3 can be expressed by the following equation (9).

H (bold) _AF1 is a channel matrix from AF2-1 to MS3, and H (bold) _AF2 is a channel matrix from AF2-2 to MS3. Further, h _{AF1_ij} in H (bold) _AF1 is a transmission path coefficient from the transmitting antenna 24-j of AF2-1 to the i-th receiving antenna of MS3, and h _{AF2_ij} in H (bold) _AF2 is AF2-2. Is the transmission line coefficient from the transmitting antenna 24-j of i to the i th receiving antenna of MS3.

From the above equations (8) and (9), the received signal when the MS 3 receives the transmission signals from the AFs 2-1 and 2-2 is as shown in the following equation (10). For the sake of simplicity, the noise term added inside the MS 3 is ignored here. In the case of the OFDM transmission system, symbols may be assigned in the frequency direction instead of the time direction, and therefore, the symbol numbers of OFDM when assigned in the frequency axis direction are shown in parentheses. R _{MS_i} ^(j) is a j-th (time or frequency direction number) signal received by the i-th receiving antenna of MS 3.

The MS 3 performs the processing shown in the following equations (11) to (13) using the received signal shown in the above equation (10) as the demodulation processing for demodulating the transmission signal S ₁ .

Further, the MS 3 performs processing shown in the following formulas (14) to (16) using the received signal shown in the formula (10) as a demodulation process for demodulating the transmission signal S _1. .

When the above equations (13) and (16) are used, the transmission signal S ₁ from the BS ₁ can be demodulated as shown in the following equation (17).

Further, in order to demodulate the transmission signal S ₂ , the received signal is processed as shown in Expression (18) using Expression (11) and Expression (12).

  Further, the received signal is processed as shown in Expression (19) using Expression (14) and Expression (15).

When the above equations (18) and (19) are used, the transmission signal S ₂ from the BS 1 can be demodulated as shown in the equation (20).

As shown in the above equations (17) and (20), the MS 3 can demodulate the transmission signals S ₁ and S ₂ of the BS 1 and can obtain a gain of diversity order number 4.

In addition, although the case where the receiving antenna of MS3 is one was demonstrated here, when MS3 has a some receiving antenna, the process similar to the above is implemented for every receiving antenna. As a result, the transmission signals S ₁ and S ₂ from the MS ₁ can be demodulated for each reception antenna, and the maximum ratio composition can be performed by linearly synthesizing the demodulation results for each reception antenna. I can.

  Thus, in this embodiment, BS1 transmits a transmission signal that has been STBC or SFBC encoded, and the signal processing unit 22 of AF2-1 and 2-2 performs AF2-1 on the signal received from BS1. , 2-2, the transmission signal is generated so that the transmission signal matrix of the signal transmitted from the 2-2 is an orthogonal matrix. Therefore, it is possible to realize high-performance transmission while suppressing an increase in the number of antennas of the BS 1 including the transmitter 10.

Embodiment 2. FIG.
FIG. 4 is a diagram illustrating a configuration example of a communication system according to the second embodiment of the present invention. The communication system of the present embodiment is the same as that of the first embodiment except that AFs 2-1 and 2-2 of the first embodiment are replaced with AFs 2a-1 and 2a-2, respectively.

  In the first embodiment, the AFs 2-1 and 2-2 each have two transmission antennas and reception antennas. However, the AFs 2a-1 and 2a-2 in the present embodiment each have one transmission antenna and reception antenna. Provide an antenna. The AFs 2a-1 and 2a-2 of the present embodiment each include a signal processing unit and a power amplification unit. In AFs 2a-1 and 2a-2, the signal processing unit performs predetermined signal processing on the signal received from BS1. And a power amplification part transmits the signal after signal processing from a transmission antenna.

  Next, the operation of the present embodiment will be described. The configuration and operation of BS1 are the same as in the first embodiment, and the transmission signal transmitted by BS1 is the same as in the first embodiment.

The transmission path matrix (channel matrix) between BS1 and AF2a-1 and 2a-2 can be expressed by the following equation (21), respectively. H (bold) ₁ represents the channel matrix from BS1 to 2a-1, and H (bold) ₂ represents the channel matrix from BS1 to 2a-2. In addition, h _{1 — ij} in H (bold) ₁ is a transmission path coefficient from the j-th transmission antenna of BS1 to the i-th reception antenna of AF2a-1, and h _{2 — ij} in H (bold) ₂ is BS1. Is the transmission line coefficient from the j-th transmitting antenna to the i-th receiving antenna of AF2a-2.

Therefore, the received signals in AF2a-1 and 2a-2 can be expressed by the following equation (22). Note that R (bold) _j is the AF2a-i received signal matrix, the row direction is the receiving antenna number, and the column direction is the transmission symbol direction. _Further, r i_j ^(k) is the j-th receive antenna (in this case, one) AF2a-i indicates the k-th received symbols (e.g., OFDMA symbols).

Next, signal processing performed by the signal processing units of the AFs 2a-1 and 2a-2 according to the present embodiment will be described. The signal processing unit according to the present embodiment generates and transmits a transmission signal as shown in the following equations (23) and (24). Expression (23) represents a transmission signal transmitted by the AF 2a-1, and Expression (24) represents a transmission signal transmitted by the AF 2a-2. Note that the signal processing function w _{i — j} ^(k) () is a function indicating signal processing for the signal processing unit of the present embodiment to generate a transmission signal based on the received signal, and is the j-th AF2a-i. It is a signal processing function which shows the process performed in order to produce | generate the kth symbol transmitted from a transmission antenna.

If the transmission signal after the above signal processing is a transmission signal matrix S (bold) _{AF of} all AFs (AF2a-1 and AF2a-2), S (bold) _AF can be expressed by Expression (25). The row direction of the transmission signal matrix S (bold) _AF is the transmission antenna number of AF2a-1, 2a-2, the first row corresponds to the transmission antenna number 1 of AF2a-1, and the second row is AF2a-. Corresponds to No. 3 transmission antenna No. 1. The column direction is the transmission signal symbol direction.

As can be seen from the above equation (25), S (bold) _AF is an orthogonal matrix. Further, equation (23), as can be seen from equation (24), the AF2a-1, generates a transmission signal of only term including S ₁ (S ₂ not including) the AF2a-2, including S ₂ A transmission signal of only a term (not including S ₁ ) is generated. In other words, decoding and re-encoding are performed in AF2a-1 and AF2a-2. In contrast to the above example, AF2a-1 may generate a transmission signal for only a term including S ₂ , and AF2a-2 may generate a transmission signal for only a term including S ₁ . That is, w _{i — j} ^(k) () is not limited to the functions shown in Expression (23) and Expression (24), and S (bold) _AF is an orthogonal matrix, and one of AF2a-1 and AF2a-2 However, it suffices to generate a transmission signal that does not include S ₁ and to generate a transmission signal that does not include S ₂ .

Next, the transmission path from AF2a-1 and 2a-2 to MS3 can be expressed by the following equation (26). H (bold) _AF1 indicates a channel matrix from AF2a-1 to MS3, and H (bold) _AF2 indicates a channel matrix from AF2a-2 to MS3. Further, h _{AF1_ij} in H (bold) _AF1 is a transmission path coefficient from the j-th transmitting antenna of AF2a-1 to the i-th receiving antenna of MS3, and h _{AF_ij} in H (bold) _AF2 is AF2a-2. Is the transmission line coefficient from the j-th transmitting antenna to the i-th receiving antenna of MS3.

Using the above equations (25) and (26), the received signal at the receiving antenna of the MS 3 for the transmission signals from AF2a-1 and AF2a-2 can be expressed by the following equation (27). For the sake of simplicity, the noise term added inside the MS 3 is ignored here. r _{MS_i} ^(j) is the j-th received signal of the i-th receiving antenna of MS 3.

In the MS 3, in order to demodulate the transmission signals S ₁ and S ₂ , processing as shown in the following equations (28) and (29) is performed using the received signal shown in the equation (27). .

In this way, the MS 3 can demodulate the transmission signals S ₁ and S ₂ from the BS 1 as shown in the above equations (28) and 29. In this embodiment, there is no improvement in diversity order as in the first embodiment, but inter-signal interference can be removed by signal processing (decoding and re-encoding) in AFs 2a-1 and 2a-2. High performance transmission can be realized. In addition, this makes it possible to reduce the amount of input power in the power amplifying units of the AFs 2a-1 and 2a-2, and to reduce the required performance required for the power amplifying unit.

As in the first embodiment, when MS 3 includes a plurality of reception antennas, the same processing as described above is performed for each reception antenna, and transmission signals S ₁ and S ₂ are demodulated for each reception signal. it can. Then, by linearly synthesizing the demodulation results for each reception antenna, maximum ratio synthesis is achieved, and further reception gain can be obtained.

  Thus, in the present embodiment, one of the two types of transmission signals is decoded by AF 2a-1 and 2a-2 so that the entire transmission signal matrix of AF 2a-1 and 2a-2 becomes an orthogonal matrix. Re-encoding was performed. Therefore, it is possible to suppress the increase in the number of antennas, eliminate inter-signal interference, and realize high-performance transmission.

  As described above, the communication system, the relay device, and the communication method according to the present invention are useful for a communication system in which MIMO transmission is performed, and are particularly suitable for a communication system including a relay device.

1 BS
2-1, 2-2, 2a-1, 2a-2 AF
3 MS
DESCRIPTION OF SYMBOLS 10 Transmitter 20 Relay machine 11 FEC encoding part 12 Modulation part 13 Data distribution part 14-1, 14-2 Resource mapping part 15-1, 15-2 Baseband / RF processing part 16-1, 16-2 Transmitting antenna 21 -1,21-2 Reception antenna 22 Signal processing unit 23-1, 23-2 Power amplification unit 24-1, 24-2 Transmission antenna

Claims (7)

A communication system comprising a transmitter, a receiver, and two or more relay devices that relay communication between the transmitter and the receiver,
The transmitter is
Two or more transmit antennas;
A data division unit that generates a divided transmission signal by dividing the transmission signal into the number of the transmission antennas, and outputs the divided transmission signal to the transmission antenna as a blocked signal by space-time block coding or frequency space block coding; ,
With
The repeater is
One or more relay receiving antennas;
One or more relay transmit antennas;
A signal processing unit that generates a relay transmission signal to be transmitted from the relay transmission antenna by performing predetermined processing on the blocked signal received from the relay reception antenna;
With
The signal processing unit sets the transmission signal matrix representing the relay transmission signal transmitted from the two or more relay apparatuses to the receiver as an orthogonal matrix, and each of the elements of the transmission signal matrix is a single divided transmission. Performing the predetermined processing to include a signal;
A communication system characterized by the above. The repeater is
An amplifying unit for amplifying the relay transmission signal and outputting the amplified signal to the corresponding transmission antenna;
The communication system according to claim 1, further comprising: The number of relay receiving antennas is two, and the number of relay transmitting antennas is two.
The communication system according to claim 1 or 2. The number of relay receiving antennas is one, and the number of relay transmitting antennas is one.
The communication system according to claim 1 or 2. The receiver
Multiple receive antennas,
With
For each reception antenna, the transmission signal is demodulated and maximum ratio combining is performed using the demodulation result for each reception antenna.
The communication system according to any one of claims 1 to 4. A relay in a communication system comprising: a transmitter; a receiver; and two or more relays that relay communication between the transmitter and the receiver;
One or more relay receiving antennas;
One or more relay transmit antennas;
Generate a relay transmission signal to be transmitted from the relay transmission antenna by performing a predetermined process on the block signal transmitted by space-time block coding or frequency space block coding received by the relay reception antenna. A signal processing unit to
With
The signal processing unit sets the transmission signal matrix representing the relay transmission signal transmitted from the two or more relay apparatuses to the receiver as an orthogonal matrix, and each of the elements of the transmission signal matrix is a single divided transmission. Performing the predetermined processing to include a signal;
A repeater characterized by that. A communication method in a communication system comprising a transmitter, a receiver, and two or more relay devices that relay communication between the transmitter and the receiver,
The transmitter generates a divided transmission signal obtained by dividing the transmission signal into the number of the transmission antennas, and outputs the divided transmission signal to the transmission antenna as a block signal by space-time block coding or frequency space block coding. A data transmission step to perform,
A signal processing step for generating a relay transmission signal to be transmitted from the relay transmission antenna by performing a predetermined process on the blocked signal received by the relay from the relay reception antenna;
Including
In the signal processing step, a transmission signal matrix representing the relay transmission signal transmitted from the two or more relay apparatuses to the receiver is an orthogonal matrix, and each element of the transmission signal matrix is a single divided transmission. Performing the predetermined processing to include a signal;
A communication method characterized by the above.

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