JP2014050040A - Time-space trellis coding mimo transmission device and receiving device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize a time-space trellis coding MIMO scheme capable of improving transmission characteristic by performing correct branch selection, even when a correlation of propagation path response is large.SOLUTION: In a mapping unit 106 of a time-space trellis coding unit 11, a transmission device 303 assigns a plurality of bits of an input signal to signal points by using mapping information having same modulation level but different signal point arrangements between transmission systems 1 and 2. This means that, when creating received signal replicas of each of receiving systems 1 and 2, a receiving device 304 can use the mapping information having different signal point arrangements between the transmission systems 1 and 2 as used by the transmission device 303, so that even when a correlation of propagation path response is large, resemblance between the received signal replicas becomes nonexistent, providing that a combination of signal point candidates is different. Therefore, correct branch selection is made possible and transmission characteristics can be improved.

Description

  The present invention relates to a space-time trellis code (STTC) transmission system applied to a multiple-input multiple-output (MIMO) system.

  FIG. 1 is a block diagram illustrating a basic configuration of a space-time trellis coded MIMO scheme. This MIMO system includes a transmission apparatus 301 with N transmission systems and a reception apparatus 302 with M reception systems. The transmission apparatus 301 includes a space-time trellis encoder 1 and N transmission antennas 4. 302 includes M receiving antennas 5 and a Viterbi decoder 6. Note that N is an integer of 2 or more, M is an integer of 1 or more, and FIG. 1 shows only a basic configuration for explaining the space-time trellis coded MIMO system. 302 also includes other components.

As illustrated in FIG. 1, the space-time trellis encoder 1 of the transmission device 301 includes a convolutional encoding unit 2 and a mapping unit 3 for each transmission system. Convolutional encoding unit 2, in between the transmission systems, a structure of the registers and weighting are the same, enter the same input signal s _1, the same state transition. The mapping unit 3 performs mapping on the convolutional coding output output by the convolutional coding unit 2 for each transmission system. Then, the signal _{x 1, x 2, ···,} x N output by the mapping unit 3 of each transmission system are transmitted from the transmit antenna 4 corresponding as a signal of the same frequency.

The Viterbi decoder 6 of the receiving apparatus 302 receives the actual received signals y ₁ , y ₂ ,..., Y _M received via the corresponding receiving antennas 5 and the estimated channel response for each reception system. A metric calculation unit 7 is provided that calculates a metric based on the distance between signal points between the received signal replica and the received signal replica. Further, the Viterbi decoder 6 estimates the input signal sequence s ₁ , s ₂ ,... Of the likely encoder by the branch selection unit 8 that performs branch selection of the trellis diagram by the Viterbi decoding method and the trace back. And a traceback unit 9 for decoding and outputting output signal sequences d ₁ , d ₂ ,...

The weighting coefficient of the convolutional coding used for the space-time trellis encoder 1 is a transmission system for the distance between signal points at the output of the space-time trellis encoder _{1 for} different input signals s ₁ , s ₂ ,. Designed to increase the sum between them. For example, the weighting coefficient is designed so that even if the distance between signal points of a certain transmission system is short, the distance is different in another transmission system.

  As described above, in the space-time trellis coded MIMO scheme, the transmission apparatus 301 uses a plurality of transmission system signals redundantly to transmit one stream of information. The metric difference between the branches becomes large, and branch selection becomes easy at the time of branch selection of the trellis diagram in Viterbi decoding. In addition, in the receiving apparatus 302, the reliability of the estimation of the input signal sequence is improved by performing Viterbi decoding using the metrics calculated from the plurality of received signals by using the signals of the plurality of receiving systems redundantly. Can be made. Therefore, in the space-time trellis coded MIMO system, transmission with less error can be realized by the diversity effect of these transmission and reception.

  In such a conventional space-time trellis-encoded MIMO system, the signal points of each transmission system are independent without being mixed, and a weighting coefficient is designed so that the distance between codewords becomes large. A common signal point arrangement was used (see Patent Document 1).

  Further, conventionally, for example, BPSK (Binary Phase Shift Keying) is used as the modulation scheme of the transmission system 1, and QPSK (Quadrature Phase Shift Keying) is used as the modulation scheme of the transmission system 2, for example, between transmission systems. A spatial multiplexing MIMO scheme using signal point arrangements with different numbers of modulation levels is known.

  Further, for example, a space division multiplexing MIMO system or a space-time coded MIMO system is proposed in which 4-bit information is divided into 2 bits, QPSK signal point arrangements having different powers are combined, and output after combining. (See Patent Document 2).

JP 2009-10939 A JP 2006-13610 A

  However, in the method of Patent Document 1, since the signal points of each transmission system are synthesized in space in an actual MIMO environment, the distance between codewords cannot be kept large. In particular, when the correlation between the propagation path responses is large, the propagation path responses are similar. Then, when a reception signal replica is created by the reception device 302, even if the combinations of signal point candidates in each transmission system are switched (for example, {transmission 1: n, transmission 2: m} (transmission system 1 signal points). Propagation of candidate n and signal point candidate m of transmission system 2) {transmission 1: m, transmission 2: n} (even if signal point candidate m of transmission system 1 and signal point candidate n of transmission system 2) are replaced) The received signal replica synthesized by complex multiplication of the path response is similar. The branch metric calculated based on the distance between the signal points between the actual received signal and the received signal replica has the same value. For this reason, the method of Patent Document 1 has a problem that accurate branch selection becomes difficult and error is likely to occur, and transmission characteristics deteriorate.

  Further, in a method using signal point arrangements with different modulation multi-level numbers between transmission systems, the information rate is lowered, and the transmission characteristics cannot be improved without impairing the information rate. Furthermore, in the method of Patent Document 2, since the signal point arrangement of the combined output is the same in each transmission system, as in the method of Patent Document 1, it becomes difficult to select an accurate branch, and it is easy to make an error. There was a problem of getting worse.

  Therefore, the present invention has been made to solve the above-mentioned problems, and its purpose is a space-time that can perform accurate branch selection and improve transmission characteristics even when the correlation of propagation path responses is large. An object of the present invention is to provide a transmitter and a receiver that realize a trellis-encoded MIMO scheme.

  The present inventors have intensively studied to achieve the above object. As a result, it has been found that in the space-time trellis coded MIMO system, mapping is performed using the mapping information of the same modulation multilevel number but different signal point arrangement between transmission systems. As a result, even when the correlation between the channel responses between the antennas is large, if the combination of signal point candidates is different, the created received signal replicas will be separated, so that accurate branch selection can be performed. As a result, the transmission characteristics can be improved as compared with the prior art.

  That is, the transmission apparatus according to claim 1 is a spatio-temporal trellis-encoded MIMO transmission apparatus including a plurality of transmission systems and a plurality of reception systems, and convolutionally encodes transmission data for each transmission system, and performs predetermined modulation. A space-time trellis coding unit that maps to a signal point arrangement of the system, and OFDM modulation or single carrier modulation for transmission data that is convolutionally coded and mapped by the space-time trellis coding unit for each transmission system A modulation unit that performs the frequency conversion of the signal generated by the modulation unit for each transmission system, and a transmission high-frequency unit that transmits the signal via a transmission antenna, the mapping in the space-time trellis coding unit is The transmission multi-level is performed using mapping information of the same signal point arrangement but different signal point arrangement between the transmission systems.

  In addition, in the transmission device according to claim 1, the transmission device according to claim 1 is configured such that a signal point arrangement different between the transmission systems is a signal point arrangement and a signal point arrangement is rotated when the signal point arrangement is rotated. It is characterized by a combination with a signal point arrangement in which the points do not overlap.

  According to a third aspect of the present invention, there is provided the transmission apparatus according to the first aspect, wherein the signal point arrangement that differs between the transmission systems is changed to one signal point arrangement and the signal point arrangement is rotated, enlarged, or reduced. In this case, it is a combination with a signal point arrangement in which there are signal points that do not overlap.

  Furthermore, the receiving device of claim 4 combines the signals for each transmission system transmitted from the transmitting device according to claim 1 in a propagation path, receives the combined signal for each receiving system, and transmits the original transmission. A receiving apparatus for restoring data, wherein the received signal is converted into a frequency by receiving the combined signal via a receiving antenna for each receiving system, and the receiving high-frequency unit converts the frequency for each receiving system. A demodulating unit that performs OFDM demodulation when OFDM modulation is performed by the modulation unit of claim 1, and performs single carrier demodulation when single carrier modulation is performed by the modulation unit of claim 1; The reception high-frequency unit uses the mapping information of the signal point arrangement with the same number of modulation multi-values between the transmission systems used for mapping in the space-time trellis coding unit. Using a channel response between the plurality of transmission systems and the plurality of reception systems estimated from the frequency-converted signal, a reception signal replica for each reception system is created, and the reception signal replica and the demodulation are generated Calculate the metric between the actual received signal demodulated by the unit, select a branch based on the metric, create a trellis diagram, and trace back the trellis diagram to decode the original transmission data And a Viterbi decoding unit.

  Further, the receiving device according to claim 5 is the receiving device according to claim 4, wherein a signal point arrangement different between the transmission systems is a signal point arrangement and a signal is obtained when the signal point arrangement is rotated. It is characterized by a combination with a signal point arrangement in which the points do not overlap.

  A receiving device according to claim 6 is the receiving device according to claim 4, wherein a signal point arrangement different between the transmission systems is changed to one signal point arrangement and the signal point arrangement is rotated, enlarged or reduced. In this case, the signal point arrangement is a combination of signal points in which there are signal points that do not overlap.

  As described above, according to the present invention, it is possible to perform accurate branch selection and improve transmission characteristics even when the correlation of propagation path responses is large.

It is a block diagram explaining the basic composition of a space-time trellis coding MIMO system. It is a block diagram which shows the whole structure of the MIMO system which consists of a transmitter and a receiver by Example 1. 3 is a block diagram illustrating configurations of an input signal processing unit, a space-time trellis coding unit, and an OFDM modulation unit included in the transmission apparatus of Embodiment 1. FIG. It is a block diagram which shows the structure of the convolutional encoding part with which the space-time trellis encoding part was equipped. It is a figure which shows a state transition in case a modulation system is 16QAM and the number of states is 64. FIG. It is a figure which shows the signal point arrangement | positioning example 1 in case a modulation system is 16QAM. It is a figure which shows the example 2 of signal point arrangement | positioning in case a modulation system is 16QAM. 3 is a block diagram illustrating configurations of an OFDM demodulator, a Viterbi decoder, and an output signal processor included in the receiving apparatus according to Embodiment 1. FIG. It is a figure explaining the creation method of the received signal replica in the metric calculation part with which the Viterbi decoding part was equipped. It is a block diagram which shows the whole structure of the MIMO system which consists of a transmitter by the Example 2, and a receiver. It is a block diagram which shows the structure of the input signal processing part with which the transmitter of Example 2 was equipped, the space-time trellis encoding part, and the SC modulation | alteration part. FIG. 10 is a block diagram illustrating configurations of an SC demodulation unit, a Viterbi decoding unit, and an output signal processing unit included in a receiving apparatus according to Embodiment 2. It is a figure which shows the computer simulation result in case a propagation path response is a low correlation. It is a figure which shows the computer simulation result in case a propagation path response is medium correlation. It is a figure which shows the computer simulation result in case a propagation path response is highly correlated. It is a figure which shows the computer simulation result in case a propagation path response is a perfect correlation. It is a figure which shows the example of signal point arrangement | positioning in case a modulation system is QPSK. It is a figure which shows the example of signal point arrangement | positioning in case a modulation system is 8PSK. It is a figure which shows the example of a signal point arrangement | positioning in case a modulation system is 16QAM. It is a figure which shows the other example of signal point arrangement | positioning in case a modulation system is 16QAM.

  Hereinafter, embodiments for carrying out the present invention will be described in detail with reference to the drawings. The present invention is characterized in that mapping information having the same number of modulation levels but different signal point arrangement is used between transmission systems. Specifically, in the mapping process in which the transmission apparatus assigns a plurality of bits of the input signal to signal points in each transmission system, the mapping information with the same modulation multi-level number but different signal point arrangement between the transmission systems When the MIMO receiving apparatus creates a received signal replica for Viterbi decoding in each reception system, the mapping information used in each transmission system is used. As a result, even if the channel response correlation is large, received signal replicas will not resemble if the combination of signal point candidates is different, so that branch selection can be performed accurately and transmission characteristics deteriorate. Can solve the problem.

[Example 1]
First, Example 1 will be described. The first embodiment is an example of a 2 × 2 STTC-MIMO-OFDM system in which a space-time trellis-encoded MIMO scheme with two transmission systems and two reception systems is applied to an OFDM (Orthogonal Frequency Division Multiplexing) system.

  FIG. 2 is a block diagram illustrating an overall configuration of the MIMO system including the transmission device and the reception device according to the first embodiment. This MIMO system is a 2 × 2 STTC-MIMO-OFDM system based on OFDM, and includes a transmission device 303 and a reception device 304. The transmission device 303 includes an input signal processing unit 10, a space-time trellis encoding unit 11, two systems of OFDM modulation units 12, two systems of transmission high-frequency units 13, and two systems of transmission antennas 14. The receiving device 304 includes two receiving antennas 15, two receiving high-frequency units 16, two OFDM demodulating units 17, a Viterbi decoding unit 18, and an output signal processing unit 19.

h ₁₁ is a propagation path response between the transmission antenna 14 of the transmission system 1 and the reception antenna 15 of the reception system 1, and h ₂₁ is between the transmission antenna 14 of the transmission system 1 and the reception antenna 15 of the reception system 2. H ₁₂ is a propagation path response between the transmission antenna 14 of the transmission system 2 and the reception antenna 15 of the reception system 1, and h ₂₂ is received by the transmission antenna 14 of the transmission system 2. It is a propagation path response to the receiving antenna 15 of the system 2. The transmission signal x ₁ of the transmission system 1 is a signal transmitted from the transmission antenna 14 of the transmission system 1, and the transmission signal x ₂ of the transmission system 2 is a signal transmitted from the transmission antenna 14 of the transmission system 2. The reception signal y ₁ receiving system 1 includes a transmission signal x ₁ and the transmission signal x ₂ is synthesized by the propagation path, a signal received through the reception antenna 15 of the reception system 1. The reception signal y ₂ of the reception system 2 is a signal that is received through the reception antenna 15 of the reception system 2 by combining the transmission signal x ₁ and the transmission signal x ₂ on the propagation path.

[Transmitter / Example 1]
Next, the transmission apparatus 303 shown in FIG. 2 will be described in detail. FIG. 3 is a block diagram illustrating configurations of the input signal processing unit 10, the space-time trellis encoding unit 11, and the OFDM modulation unit 12 included in the transmission device 303 illustrated in FIG. The input signal processing unit 10 includes an energy spreading unit 101, an outer code encoding unit 102, and an outer interleaving unit 103. The energy diffusion unit 101 inputs information to be transmitted, and performs energy diffusion processing on the information to eliminate the bias of the data bits 0 and 1. Outer code encoding section 102 performs error correction processing such as Reed-Solomon code on the signal subjected to energy spreading processing by energy spreading section 101. Outer interleaving section 103 shuffles the data that has been subjected to error correction processing by outer code encoding section 102 between data at different positions.

  The configuration of the input signal processing unit 10 shown in FIG. 3 is an example, and the present invention is not limited to this configuration. For example, the input signal processing unit 10 may perform synchronization processing, scramble processing, and the like of information input in a packet format.

  The space-time trellis encoding unit 11 includes two systems of a convolutional encoding unit 104, an inner interleaving unit 105, and a mapping unit 106. When the signal subjected to the input signal processing by the input signal processing unit 10 is input, the space-time trellis encoding unit 11 distributes the same input signal to two transmission systems. The convolutional encoding unit 104 performs convolutional encoding on the input signal from the input signal processing unit 10.

FIG. 4 is a block diagram illustrating a configuration of the convolutional encoding unit 104 provided in the space-time trellis encoding unit 11 illustrated in FIG. The convolutional encoding unit 104 is an example corresponding to the case where the modulation method is 16QAM (16-Quadrature Amplitude Modulation), and includes a serial / parallel conversion unit 30, a predetermined number of bit registers 31, a predetermined number of multipliers 32, And a modulo adder 33. g is a weighting coefficient and is set in advance. The serial / parallel converter 30 converts the serial input signal b ₃ b ₂ b ₁ b ₀ into a parallel signal, and distributes it for each bit. The bit register 31 holds a value one bit (symbol) before. The multiplier 32 multiplies each bit distributed by the serial / parallel converter 30 or a past bit held in the bit register 31 by a weighting coefficient g. The multiplication results by the multiplier 32 are input to the modulo adder 33, respectively. The modulo adder 33 receives the multiplication results of the multiplier 32, adds all the multiplication results modulo 16, and outputs a 4-bit signal c ₃ c ₂ c ₁ c ₀ .

Here, a value representing a set of bits held in all the bit registers 31 in decimal notation is referred to as a “state”. When the number of bit registers 31 is 6, the number of states is 2 ⁶ = 64. It becomes. The convolutional coding unit 104 transitions from a certain state to the next state in accordance with the input signal. This is called “state transition”.

FIG. 5 is a diagram illustrating state transition when the modulation scheme is 16QAM and the number of states is 64 in the convolutional coding unit 104 illustrated in FIG. 4. A branch between states is called a branch. In the convolutional coding unit 104, an input signal and an output signal of each transmission system correspond one-to-one. In FIG. 5, when the number of transmission systems is M, the input signal is b ₃ b ₂ b ₁ b ₀ , and the number of branches is 16, the output signal of the transmission system 1 is c ¹ ₃ c ¹ ₂ c ¹ ₁ c ¹ ₀ . ,., indicates that output signal of the transmission system M is ^{_{c M 3 c M 2 c M}} 1 c M 0. The number of branches is 16 because the input signal b ₃ b ₂ b ₁ b ₀ is 4 bits, there are 2 ⁴ = 16 combinations, and the state of the convolutional coding unit 104 is 16 according to the input. It is because it changes on the street. In addition, the output signal is different for each of the transmission systems 1 to M with respect to the same input signal. The configuration of the convolutional coding unit 104 is the same between the transmission systems 1 to M, but the weighting coefficient g is different. Because. Thus, the convolutional encoding unit 104 outputs different signals for the same input signal in the transmission systems 1 to M.

  Returning to FIG. 3, the inner interleaving unit 105 of the space-time trellis coding unit 11 performs frequency interleaving and time interleaving on the signal convolutionally encoded by the convolutional encoding unit 104. The mapping unit 106 performs mapping processing on the signal interleaved by the inner interleaving unit 105. Specifically, the mapping unit 106 uses a plurality of bits of the input signal (for example, the number of bits of the input signal) according to the numbered mapping rule using the mapping information having the same modulation multi-level number but different signal point arrangement between the transmission systems. , 4 bits are assigned to signal points when the modulation method is 16QAM.

  Here, the mapping information in which the signal point arrangement differs between transmission systems is the position of each signal point arranged on the IQ axis in one signal point arrangement and the IQ axis in the other signal point arrangement. Further, it means a combination in which at least one signal point is arranged at a different position between each signal point. For example, it refers to a combination of one signal point arrangement and a signal point arrangement that prevents signal points from overlapping when rotated. In addition, for example, it refers to a combination of one signal point arrangement and a signal point arrangement in which signal points do not overlap when enlarged or reduced, and further, one signal point arrangement and rotation and enlargement or A signal point arrangement combination in which signal points do not overlap when reduced. For example, it refers to a combination of one signal point arrangement and a signal point arrangement in which there are signal points that do not overlap when rotated, enlarged, or reduced. It is desirable that the distance between signal points in each signal point arrangement is as far as possible.

  FIG. 6 is a diagram illustrating a signal point arrangement example 1 in the mapping unit 106 when the modulation scheme is 16QAM. The modulation multilevel number is 4 when the modulation method is 16QAM. FIG. 6A shows the signal point arrangement in the mapping unit 106 of the transmission system 1, which is the same as the conventional 16QAM signal point arrangement. FIG. 6A shows the signal point arrangement in the mapping unit 106 of the transmission system 2, which is different from the signal point arrangement shown in FIG. The mapping unit 106 of the transmission system 1 assigns 4 bits of the input signal to a predetermined signal point according to the mapping rule numbered in the conventional 16QAM signal point arrangement shown in FIG. Further, the mapping unit 106 of the transmission system 2 assigns 4 bits of the input signal to a predetermined signal point according to the mapping rule numbered to the new 16QAM signal point arrangement shown in FIG.

  FIG. 7 is a diagram illustrating a signal point arrangement example 2 in the mapping unit 106 when the modulation scheme is 16QAM. FIG. 7A shows the signal point arrangement in the mapping unit 106 of the transmission system 1, and is the same as the conventional 16QAM signal point arrangement as in FIG. 6A. FIG. 7 (a) shows signal point arrangement in the mapping unit 106 of the transmission system 2, which is different from the signal point arrangement shown in FIG. 7 (a), and the signal point shown in FIG. 7 (a). The arrangement is rotated clockwise by a predetermined angle around the origin, and there is no overlap with the signal points in FIG. The mapping unit 106 of the transmission system 1 assigns 4 bits of the input signal to a predetermined signal point according to the mapping rule numbered in the conventional 16QAM signal point arrangement shown in FIG. Further, the mapping unit 106 of the transmission system 2 receives the input signal in accordance with the mapping rule numbered in the new 16QAM signal point arrangement (an arrangement obtained by rotating the conventional 16QAM signal point arrangement) shown in FIG. Are assigned to a predetermined signal point.

  As described above, the mapping unit 106 uses the mapping information shown in FIG. 6 or FIG. 7 between the transmission system 1 and the transmission system 2 using the mapping information having the same modulation multi-level number but different signal point arrangement. According to the numbered mapping rule, 4 bits of the input signal are assigned to signal points.

  In the spatio-temporal trellis encoding unit 11 illustrated in FIG. 3, the mapping unit 106 is provided in the subsequent stage of the inner interleaving unit 105, but the mapping unit 106 may be provided in the previous stage of the inner interleaving unit 105. . As shown in FIG. 3, the space-time trellis encoding unit 11 includes a mapping unit 106 at the subsequent stage of the inner interleaving unit 105 so that the capacity of the signal stored in the memory of the inner interleaving unit 105 can be reduced. Become.

  Returning to FIG. 3, the OFDM modulation unit 12 includes an OFDM frame configuration unit 107, an IFFT (Inverse Fast Fourier Transform) unit 108, a GI (Guard Interval) addition unit 109, and an orthogonal modulation unit 110. Two systems are provided. For each transmission system 1 and 2, OFDM frame configuration section 107 receives a signal that has been space-time trellis encoded by space-time trellis encoding section 11, assigns data and pilot to subcarriers on the frequency axis, and generates an OFDM frame. Configure. IFFT section 108 performs inverse fast Fourier transform on the frequency domain signal of the OFDM frame configured by OFDM frame configuration section 107 to generate a time domain signal. The GI adding unit 109 copies the rear part of the signal as a guard period to the previous part and adds a GI to the time domain signal generated by the IFFT unit 108. The orthogonal modulation unit 110 performs orthogonal modulation on an IF (Intermediate Frequency) signal using an OFDM complex baseband signal with respect to the signal to which the GI is added by the GI addition unit 109 to generate an IF signal.

  The transmission high-frequency unit 13 receives the IF signal modulated by the OFDM modulation unit 12 for each of the transmission systems 1 and 2, converts the IF signal into a radio frequency signal, amplifies the signal to a specified power, and transmits the transmission system 1. , Transmitted via every two transmitting antennas 14.

  As described above, according to the transmission apparatus 303 in the MIMO system of Example 1 (2 × 2 STTC-MIMO-OFDM system in which the space-time trellis-encoded MIMO scheme is applied to the OFDM system), the space-time trellis encoding unit 11 The mapping unit 106 assigns a plurality of bits of the input signal to signal points according to the mapping information of the signal point arrangement with the same number of modulation multilevels but different between the transmission systems 1 and 2. Accordingly, when the reception device 304 creates reception signal replicas of the reception systems 1 and 2, the correlation between the propagation path responses is large by using the mapping information of the different signal point arrangements used in the transmission device 303. Even in this case, the received signal replicas will not be similar if the combinations of signal point candidates are different. Therefore, accurate branch selection can be performed and transmission characteristics can be improved.

[Receiver / Example 1]
Next, the receiving apparatus 304 shown in FIG. 2 will be described in detail. FIG. 8 is a block diagram illustrating configurations of the OFDM demodulator 17, the Viterbi decoder 18, and the output signal processor 19 included in the reception device 304 illustrated in FIG. The signals transmitted from the transmission antennas 14 of the transmission systems 1 and 2 of the transmission apparatus 303 shown in FIG. . The reception high-frequency unit 16 converts a signal received by the reception antenna 15 into an IF signal.

  The OFDM demodulator 17 includes an orthogonal demodulator 111, a symbol synchronizer 112, an FFT (Fast Fourier Transform) unit 113, a propagation path estimator 114, and an internal deinterleaver 115 for two systems. The orthogonal demodulation unit 111 demodulates the IF signal converted by the reception high frequency unit 16 into a complex baseband signal. The symbol synchronization unit 112 detects the beginning of the OFDM symbol for the complex baseband signal demodulated by the orthogonal demodulation unit 111. The FFT unit 113 performs fast Fourier transform on the effective symbol from which the GI has been removed from the signal from the symbol synchronization unit 112, and converts the signal in the time domain into a signal in the frequency domain. The propagation path estimation unit 114 estimates a propagation path response from a pilot carrier or the like of the frequency domain signal converted by the FFT unit 113. The inner deinterleaving unit 115 performs an inner deinterleaving process on the data and the propagation path response, which is opposite to the inner interleaving process performed by the inner interleaving unit 105 shown in FIG.

  The Viterbi decoding unit 18 includes two metric calculation units 116, and further includes a branch selection unit 117 and a traceback unit 118. The metric calculator 116 receives the signal demodulated by the OFDM demodulator 17 and is used by the mapping system 106 of the space-time trellis encoder 11 in the transmitter 303 shown in FIG. All the signals in the transmission systems 1 and 2 based on the mapping information of different signal point arrangements with the same modulation multi-value number between them and the propagation path response estimated by the propagation path estimation unit 114 of the OFDM demodulation unit 17 A received signal replica is created for a combination of points. Then, the metric calculation unit 116 calculates a metric from the distance between the created received signal replica and the actual received signal (input signal).

FIG. 9 is a diagram for explaining a reception signal replica creation method in the metric calculation unit 116. The signal of transmission system 1 (transmission signal 1) and the signal of transmission system 2 (transmission signal 2) are the transmission systems used in mapping section 106 of space-time trellis coding section 11 in transmission apparatus 303 shown in FIG. It is a combination of any one of the signal point arrangements of 1 and 2. The metric calculation unit 116 multiplies these candidate signals by the propagation path response and adds them to all combinations of signal point candidates of the transmission systems 1 and 2 to create a received signal replica. Specifically, as shown in FIG. 2, propagation path responses h ₁₁ , h ₂₁ , h ₁₂ , h ₂₂ and actual received signals y ₁ , y _{2 are used} as shown in FIG. metric calculation unit 116, for example, with select candidate α from the signal point arrangement of the transmission system 1, selects a candidate β from the signal point arrangement of the transmission system 2, multiplying the channel response h ₁₁ to a signal candidate α Then, the signal of candidate β is multiplied by the propagation path response h ₁₂ , and these multiplication results are added to create a received signal replica y ′ ₁ . In addition, the metric calculation unit 116 of the reception system 2 selects, for example, the candidate α from the signal point arrangement of the transmission system 1, selects the candidate β from the signal point arrangement of the transmission system 2, and transmits a channel response to the signal of the candidate α. In addition to multiplying by h ₂₁ , the signal of candidate β is multiplied by the propagation path response h ₂₂ , and these multiplication results are added to create a received signal replica y ′ ₂ . Then, the metric calculation unit 116 of the reception system 1 calculates a metric from the distance between the created reception signal replica y ′ ₁ and the actual reception signal y ₁ . In addition, the metric calculation unit 116 of the reception system 2 calculates a metric from the distance between the generated reception signal replica y ′ ₂ and the actual reception signal y ₂ .

As described above, the metric calculation unit 116 selects a candidate combination of the transmission signals 1 and 2 using mapping information of signal point arrangements different between the transmission systems 1 and 2 when creating the reception signal replica. I made it. As a result, when the channel response correlation is large, the received signal replicas y ′ ₁ and y ′ ₂ do not resemble each other even if the combinations of signal point candidates are interchanged between the transmission systems 1 and 2. . As described above, conventionally, a combination of candidates is selected using the same signal point arrangement between the transmission systems 1 and 2, and therefore, when the correlation of the channel response is large, the transmission system 1 and 2 When the combinations of candidates are replaced, the received signal replicas y ′ ₁ and y ′ ₂ may be similar to each other, but this is not the case in the first embodiment. Thereby, an accurate branch selection can be performed in the branch selection unit 117 described later, and as a result, transmission characteristics can be improved as compared with the conventional case.

  Returning to FIG. 8, the branch selection unit 117 of the Viterbi decoding unit 18 selects a branch of the state transition diagram based on the metric calculated by the metric calculation unit 116 of the reception systems 1 and 2, and sets the specified number of paths. Create a trellis diagram. The traceback unit 118 traces back and decodes the path with the minimum metric sum from the trellis diagram created by the branch selection unit 117.

  The output signal processing unit 19 includes an outer deinterleaving unit 119, an outer code decoding unit 120, and an energy despreading unit 121, and performs the reverse process of the input signal processing unit 10 in the transmission device 303 shown in FIG. The outer deinterleaving unit 119 receives the Viterbi-decoded signal by the Viterbi decoding unit 18 and performs an outer deinterleaving process opposite to the outer interleaving process by the outer interleaving unit 103 shown in FIG. Apply. Outer code decoding section 120 performs decoding of the outer code corresponding to outer code encoding section 102 shown in FIG. 3 on the signal that has been deinterleaved by outer deinterleaving section 119. The energy despreading unit 121 performs an energy despreading process opposite to the energy spreading process performed by the energy spreading unit 101 shown in FIG. 3 on the signal subjected to the outer code decoding by the outer code decoding unit 120. The signal subjected to the output signal processing by the output signal processing unit 19 is output as restored information.

  As described above, according to the receiving apparatus 304 in the MIMO system of the first embodiment (2 × 2 STTC-MIMO-OFDM system in which the space-time trellis coded MIMO scheme is applied to the OFDM system), the metric calculation unit of the Viterbi decoding unit 18 116 uses the mapping information of the signal point arrangement different between the transmission systems 1 and 2 used in the transmission apparatus 303 to generate the reception signal replicas of the reception systems 1 and 2. As a result, even if the channel response correlation is large, the received signal replicas will not be similar if the combinations of signal point candidates are different. Therefore, accurate branch selection can be performed by the branch selection unit 117, and transmission characteristics can be improved.

[Example 2]
Next, Example 2 will be described. The second embodiment is an example of a 2 × 2 STTC-MIMO system in which the space-time trellis coded MIMO scheme with two transmission systems and two reception systems is applied to a single-carrier (SC) system.

FIG. 10 is a block diagram illustrating an overall configuration of a MIMO system including a transmission device and a reception device according to the second embodiment. This MIMO system is a single carrier 2 × 2 STTC-MIMO system, and includes a transmission apparatus 305 and a reception apparatus 306. The transmission device 305 includes an input signal processing unit 10, a space-time trellis encoding unit 11, two SC modulation units 20, two transmission high-frequency units 13, and two transmission antennas 14. The receiving device 306 includes two receiving antennas 15, two receiving high-frequency units 16, two SC demodulating units 21, a Viterbi decoding unit 18, and an output signal processing unit 19. Transmission path responses h ₁₁ , h ₂₁ , h ₁₂ , h ₂₂ , transmission signals x ₁ , x ₂ and reception signals y ₁ , y ₂ are the same as those in the MIMO system of the first embodiment shown in FIG.

[Transmitter / Example 2]
Next, the transmission apparatus 305 illustrated in FIG. 10 will be described in detail. FIG. 11 is a block diagram illustrating configurations of the input signal processing unit 10, the space-time trellis encoding unit 11, and the SC modulation unit 20 included in the transmission device 305 illustrated in FIG. Comparing the transmission apparatus 303 of the first embodiment shown in FIG. 3 with the transmission apparatus 305 of the second embodiment shown in FIG. 11, the transmission high frequency unit 13 and the transmission antenna 14 are the same, and the transmission device 305 is different in that it includes the SC modulation unit 20 instead of the OFDM modulation unit 12 of the transmission device 303. Since the input signal processing unit 10, the space-time trellis encoding unit 11, and the transmission high-frequency unit 13 of the transmission device 305 are the same as the components of the transmission device 303, description thereof is omitted here. However, the inner interleaving unit 105 of the space-time trellis coding unit 11 in the transmission apparatus 305 does not perform frequency interleaving.

  Information to be transmitted is processed in the input signal processing unit 10 and the space-time trellis encoding unit 11. The SC modulation unit 20 includes two systems of reference signal insertion units 201, waveform shaping units 202, and orthogonal modulation units 203. The reference signal insertion unit 201 inputs the space-time trellis-encoded signal by the space-time trellis encoding unit 11 for each of the transmission systems 1 and 2, and synchronizes and propagates the response to the input transmission symbol string signal. Insert a reference signal such as a known signal for estimating. The waveform shaping unit 202 performs waveform shaping on the signal with the reference signal inserted by the reference signal insertion unit 201 by performing filter processing and aperture correction using a root roll-off filter. The quadrature modulation unit 203 performs quadrature modulation on the signal shaped by the waveform shaping unit 202 using a single carrier complex baseband signal to generate an IF signal.

  The signal subjected to SC modulation by the SC modulation unit 20 is converted into a radio frequency signal by the transmission high frequency unit 13, amplified to a prescribed power, and transmitted through the transmission antenna 14.

  As described above, according to the transmission apparatus 305 in the MIMO system of Embodiment 2 (2 × 2 STTC-MIMO system in which the space-time trellis coded MIMO scheme is applied to a single carrier system), the space-time is the same as in Embodiment 1. The mapping unit 106 of the trellis encoding unit 11 assigns a plurality of bits of the input signal to signal points according to the mapping information of the signal point arrangement that is the same in the number of modulation multilevels but different between the transmission systems 1 and 2. . Thereby, in the receiving apparatus 306, by using the mapping information of the signal point arrangement different between the transmission systems 1 and 2 used in the transmitting apparatus 305, even if the correlation of the propagation path response is large, the signal point candidates If the combinations are different, the received signal replicas will not be similar. Therefore, accurate branch selection can be performed and transmission characteristics can be improved.

[Receiver / Embodiment 2]
Next, the receiving apparatus 306 shown in FIG. 10 will be described in detail. FIG. 12 is a block diagram illustrating configurations of the SC demodulation unit 21, the Viterbi decoding unit 18, and the output signal processing unit 19 included in the reception device 306 illustrated in FIG. When the receiving device 304 of the first embodiment shown in FIG. 8 and the receiving device 306 of the second embodiment shown in FIG. 12 are compared, both the receiving devices 304 and 306 include the receiving antenna 15, the receiving high-frequency unit 16, and the Viterbi decoding unit. 18 and the output signal processing unit 19, and the receiving apparatus 306 is different in that it includes an SC demodulating section 21 instead of the OFDM demodulating section 17 of the receiving apparatus 304. The reception high-frequency unit 16, the Viterbi decoding unit 18, and the output signal processing unit 19 of the reception device 306 are the same as the components of the reception device 304, and thus description thereof is omitted here.

  The signals transmitted from the transmission antennas 14 of the transmission systems 1 and 2 of the transmission apparatus 305 shown in FIG. 11 are combined in space, and the combined signal is received via the receiving antennas 15 of the reception systems 1 and 2. The reception high-frequency unit 16 converts it to an IF signal.

  The SC demodulation unit 21 includes two systems of an orthogonal demodulation unit 204, a waveform shaping unit 205, a synchronization unit 206, a propagation path estimation unit 207, and an internal deinterleave unit 208. The orthogonal demodulation unit 204 demodulates the IF signal converted by the reception high frequency unit 16 into a complex baseband signal. The waveform shaping unit 205 shapes the waveform by subjecting the complex baseband signal demodulated by the orthogonal demodulation unit 204 to filter processing using a root roll-off filter. The synchronization unit 206 detects the head of a single carrier block with respect to the signal waveform-shaped by the waveform shaping unit 205. The propagation path estimation unit 207 estimates the propagation path response from the reference signal with respect to the signal whose head is detected by the synchronization unit 206. The inner deinterleaving unit 208 performs an inner deinterleaving process on the data and the propagation path response, which is opposite to the inner interleaving process performed by the inner interleaving unit 105 shown in FIG.

  Then, the signal demodulated by the SC demodulator 21 is Viterbi decoded by the Viterbi decoder 18 and output opposite to the input signal processing by the input signal processor 10 shown in FIG. Signal processing is performed and the restored information is output.

  As described above, according to the receiving apparatus 306 in the MIMO system of the second embodiment (2 × 2 STTC-MIMO system in which the space-time trellis coded MIMO scheme is applied to a single carrier system), Viterbi decoding is performed as in the first embodiment. The metric calculation unit 116 of the unit 18 creates reception signal replicas of the reception systems 1 and 2 using mapping information of signal point arrangements different between the transmission systems 1 and 2 used in the transmission device 305. . As a result, even if the channel response correlation is large, the received signal replicas will not be similar if the combinations of signal point candidates are different. Therefore, accurate branch selection can be performed by the branch selection unit 117, and transmission characteristics can be improved.

[Computer simulation results]
Next, a computer simulation result will be described. FIG. 13 is a diagram showing a computer simulation result when the channel response is low correlation, FIG. 14 is a diagram showing a computer simulation result when the channel response is medium correlation, and FIG. 15 is a diagram showing the channel simulation result. FIG. 16 is a diagram showing a computer simulation result when the response is highly correlated, and FIG. 16 is a diagram showing a computer simulation result when the channel response is completely correlated.

  13 to 16, the horizontal axis represents CNR, and the vertical axis represents BER. The polygonal broken line indicates the computer simulation result of the prior art by the 2 × 2 STTC-MIMO system having the number of transmission systems of 2 and the number of reception systems of 2 described in Patent Document 1, and the polygonal line of the triangular mark indicates the first embodiment. Shows computer simulation results. The modulation schemes of the conventional technique and the first embodiment are both 16QAM. In the conventional technique, the transmission systems 1 and 2 perform mapping using the same signal point arrangement shown in FIG. In systems 1 and 2, mapping was performed using different signal point arrangements shown in FIGS. Under such conditions, the simulation results of the transmission characteristics in the rice fading environment were obtained by changing the correlation of the propagation path response as shown in FIGS.

FIG. 13 shows a low correlation case where the transmission correlation coefficient of the propagation path response is 0.3 and the reception correlation coefficient is 0.3, and FIG. 14 shows that the transmission correlation coefficient of the propagation path response is 0. .7, the case of medium correlation with a reception correlation coefficient of 0.3 is shown, and FIG. 15 shows a high correlation with a transmission correlation coefficient of 0.9 and a reception correlation coefficient of 0.9. The case of correlation is shown, and FIG. 16 shows the case of complete correlation where the transmission correlation coefficient of the channel response is 1.0 and the reception correlation coefficient is 1.0. From these figures, the required CNR of Example 1 with a BER of 2 × 10 ⁻⁴ is 0.5 dB in the middle correlation of FIG. 14 and 1.5 dB in the high correlation of FIG. It can be seen that the complete correlation is lower by 9.5 dB. Thereby, the transmission characteristic can be improved as compared with the prior art as the correlation coefficient of the propagation path response increases.

[Example of signal point arrangement]
Next, an example of signal point arrangement used in the first and second embodiments will be described. In the following, a new signal point arrangement different from the conventional one is provided for the cases where the modulation schemes are QPSK, 8PSK (8-Phase Shift Keying) and 16QAM. The conventional signal point arrangement is used for the transmission system 1, and the new signal point arrangement is used for the transmission system 2.

  FIG. 17 is a diagram illustrating an example of signal point arrangement when the modulation method is QPSK. FIG. 17A illustrates the signal point arrangement of the transmission system 1, and FIG. 17B illustrates the signal point arrangement of the transmission system 2. . The modulation multi-level number is 2 when the modulation method is QPSK. In the conventional QPSK signal point arrangement, as shown in FIG. 17A, the set of signal points (real part, imaginary part) is {(1,0), (0,1), (-1,0). , (0, -1)}, and the normalization coefficient to be multiplied to make the average power 1 is 1. In the new QPSK signal point arrangement, as shown in FIG. 17 (a), the set of signal points is {(0,0), (cos (0/3 × π), sin (0/3 × π)). , (Cos (2/3 × π), sin (2/3 × π)), (cos (4/3 × π), sin (4/3 × π))}, and the average power is 1 Therefore, the normalization coefficient to be multiplied is 1 / √0.75. In addition, you may make it use what rotated the signal point shown to Fig.17 (a) (a).

  FIG. 18 is a diagram illustrating an example of signal point arrangement when the modulation scheme is 8PSK. (A) shows the signal point arrangement of the transmission system 1, and (A) shows the signal point arrangement of the transmission system 2. . The modulation multi-level number is 3 when the modulation method is 8PSK. In the conventional 8PSK signal point arrangement, as shown in FIG. 18A, a set of signal points (real part, imaginary part) is {(√2,0), (1,1), (0, √ 2), (-1,1), (-√2,0), (-1, -1), (0, -√2), (1, -1)}, and average power is 1 Therefore, the normalization coefficient to be multiplied is 1 / √2. In the new 8PSK signal point arrangement, as shown in FIG. 18 (a), the set of signal points is {(cos (0/3 × π) / 2, sin (0/3 × π) / 2), ( cos (2/3 × π) / 2, sin (2/3 × π) / 2), (cos (4/3 × π) / 2, sin (4/3 × π) / 2), (cos ( 3/5 × π), sin (3/5 × π)), (cos (5/5 × π), sin (5/5 × π)), (cos (7/5 × π), sin (7 / 5 × π)), (cos (9/5 × π), sin (9/5 × π)), (cos (11/5 × π), sin (11/5 × π))}, The normalization coefficient to be multiplied to make the average power 1 is 1 / √0.71875. The signal point shown in FIG. 18 (a) may be rotated, or the signal point shown in FIG. 18 (a) may be rotated (inner circle (signal point α) and An outer circle (including one obtained by independently rotating the signal point β) may be used.

  FIG. 19 is a diagram illustrating an example of signal point arrangement when the modulation scheme is 16QAM. FIG. 19A illustrates the signal point arrangement of the transmission system 1, and FIG. 19B illustrates the signal point arrangement of the transmission system 2. . The modulation multilevel number is 4 when the modulation method is 16QAM. In the conventional 16QAM signal point arrangement, as shown in FIG. 19A, the set of signal points (real part, imaginary part) is {(-3,3), (-1,3), (-1 , 1), (-3,1), (1,3), (3,3), (3,1), (1,1), (1, -1), (3, -1), ( 3, -3), (1, -3), (-3, -1), (-1, -1), (-1, -3), (-3, -3)} and average power The normalization coefficient to be multiplied to make 1 is 1 / √10. As shown in FIG. 19A, one of the new 16QAM signal point arrangements is that the set of signal points is {(-5,1), (-3,3), (-1,5), ( -1,1), (1,3), (3,5), (5,3), (3,1), (1, -5), (1, -1), (5, -1) , (3, -3), (-5, -3), (-3, -1), (-1, -3), (-3, -5)}, so that the average power is 1 The normalization coefficient multiplied by 1 / √20. In addition, you may make it use what rotated the signal point shown to Fig.19 (a) (a).

  FIG. 20 is a diagram showing another example of signal point arrangement when the modulation method is 16QAM. In contrast to the signal point arrangement of the transmission system 1 shown in FIG. The signal point arrangement of system 2 is shown. Another one of the new 16QAM signal point arrangements is that the set of signal points (real part, imaginary part) is {(-5,3), (-3,5) as shown in FIG. , (-1,3), (-3,1), (1,3), (3,5), (5,3), (3,1), (1, -3), (3,- 1), (5, -3), (3, -5), (-5, -3), (-3, -1), (-1, -3), (-3, -5)} Yes, the normalization coefficient to be multiplied to make the average power 1 is 1 / √22. Another one of the new 16QAM signal point arrangements is that the set of signal points is {(−3,2), (−2,3), (−1, as shown in FIG. 2), (-2,1), (1,2), (2,3), (3,2), (2,1), (1, -2), (2, -1), (3 , -2), (2, -3), (-3, -2), (-2, -1), (-1, -2), (-2, -3)} and the average power is The normalization coefficient multiplied to 1 is 1 / √9. Note that the signal points shown in FIGS. 20 (c) and 20 (d) are rotated (including 8 signal points close to the origin and 8 signal points far from the origin independently rotated). May be used.

  Another one of the new 16QAM signal point arrangements is that the set of signal points is {(-4,1), (-2,3), (0,3) as shown in FIG. ), (-2,1), (0,1), (2,3), (4,3), (2,1), (0, -3), (2, -1), (4, -1), (2, -3), (-4, -3), (-2, -1), (0, -1), (-2, -3)} and the average power is 1. Therefore, the normalization coefficient to be multiplied is 1 / √11. In addition, you may make it use what rotated the signal point shown in FIG.

  Another one of the new 16QAM signal point arrangements is that the set of signal points is {(-5,3), (-3,5), (0,2) as shown in FIG. ), (-5,0), (0,5), (3,5), (5,3), (2,0), (0, -2), (5,0), (5,- 3), (3, -5), (-5, -3), (-2,0), (0, -5), (-3, -5)}, so that the average power is 1 The normalization coefficient multiplied by is 1 / √24.25. Another one of the new 16QAM signal point arrangements is that the set of signal points is {(-3,3), (-1,5), (-1, 1), (-5,1), (1,5), (3,3), (5,1), (1,1), (1, -1), (5, -1), (3 , -3), (1, -5), (-5, -1), (-1, -1), (-1, -5), (-3, -3)} and the average power is The normalization factor to be multiplied to 1 is 1 / √18. Note that the signal points shown in FIGS. 20 (f) and (g) are rotated (including four signal points close to the origin and twelve signal points far from the origin independently rotated). May be used.

  As described above, according to the signal point arrangement shown in FIGS. 17 to 20, since the signal points are arranged at integer positions or positions represented by sine and cosine functions, computation using the signal points is performed. Processing becomes easy and processing load can be reduced. The same applies to FIGS. 6 and 7.

  Further, FIGS. 19 and 20 are given as examples of signal point arrangements when the modulation method is 16QAM, but some of them are the signal points of 32 points in the conventional signal point arrangement when the modulation method is 32QAM. Among them, the signal point arrangement is obtained by arbitrarily extracting 16 points. In addition to these, the signal point arrangement obtained by arbitrarily extracting 16 points out of the 64 signal points in the conventional signal point arrangement when the modulation method is 64QAM. May be used. By using such a signal point arrangement, the arithmetic processing using the signal point can be realized in the same way as in the case of 64QAM, so that the arithmetic processing becomes easy and the processing load can be reduced.

  The present invention has been described with reference to the first and second embodiments. However, the present invention is not limited to the first and second embodiments, and various modifications can be made without departing from the technical idea thereof. For example, in the first and second embodiments, the 2 × 2 STTC-MIMO system having two transmission systems and two reception systems has been described, but the present invention is not limited to such a configuration. By expanding the number of systems and the number of reception systems, it can be applied to a MIMO system having a larger number of transmission systems and reception systems. In this case as well, different signal point arrangements are used between the transmission systems.

  Moreover, the combinations of signal point arrangements shown in FIGS. 6, 7, and 17 to 20 are examples, and the present invention is not limited to such combinations. In the first and second embodiments, the combination of the conventional signal point arrangement and the new signal point arrangement is used between the transmission systems. However, the new signal point arrangement is not used without using the conventional signal point arrangement. A combination of different signal point arrangements may be used.

  In addition, as shown in FIGS. 7A, 7A, 19A, 19B, and 20O, the signal point arrangements that differ between the transmission systems are equally spaced. It is desirable to use the signal point arrangement as shown in FIG. This eliminates the bias of signal points that are more likely to be erroneous in signal point arrangements having equally spaced signal points than in signal point arrangements having signal points that are not evenly spaced, thus reducing the possibility of transmission errors. This is because the transmission characteristics can be further improved.

DESCRIPTION OF SYMBOLS 1 Space-time trellis encoder 2 Convolutional encoding part 3 Mapping part 4 Transmission antenna 5 Reception antenna 6 Viterbi decoder 7 Metric calculation part 8 Branch selection part 9 Trace back part 10 Input signal processing part 11 Space-time trellis encoding part Reference Signs List 12 OFDM modulation unit 13 transmission high frequency unit 14 transmission antenna 15 reception antenna 16 reception high frequency unit 17 OFDM demodulation unit 18 Viterbi decoding unit 19 output signal processing unit 20 SC modulation unit 21 SC demodulation unit 30 serial / parallel conversion unit 31 bit register 32 multiplication 33 Modulo adder 101 Energy spreading unit 102 Outer encoding unit 103 Outer interleaving unit 104 Convolutional encoding unit 105 Inner interleaving unit 106 Mapping unit 107 OFDM frame configuration unit 108 IFFT unit 109 GI addition unit 110 Orthogonal modulation unit 111 Orthogonal demodulation 112 symbol synchronization unit 113 FFT unit 114 propagation path estimation unit 115 inner deinterleaving unit 116 metric calculation unit 117 branch selection unit 118 traceback unit 119 outer deinterleaving unit 120 outer code decoding unit 121 energy despreading unit 201 reference signal insertion unit 202 Waveform shaping unit 203 Orthogonal modulation unit 204 Orthogonal demodulation unit 205 Waveform shaping unit 206 Synchronization unit 207 Propagation path estimation unit 208 Deinterleaving units 301, 303, 305 Transmitting devices 302, 304, 306 Receiving devices

Claims (6)

In a transmitter of a space-time trellis coded MIMO system consisting of a plurality of transmission systems and a plurality of reception systems,
For each transmission system, a space-time trellis encoding unit that convolutionally encodes transmission data and maps it to a signal point arrangement of a predetermined modulation scheme;
For each transmission system, a modulation unit that performs OFDM modulation or single carrier modulation on transmission data subjected to convolutional coding and mapping by the space-time trellis coding unit;
A transmission high-frequency unit that performs frequency conversion of the signal generated by the modulation unit and transmits the signal via a transmission antenna for each transmission system,
The mapping in the space-time trellis encoder is:
A transmission apparatus characterized in that mapping is performed using mapping information of different signal point arrangements with the same modulation multi-level number but different between the transmission systems. The transmission apparatus according to claim 1,
The signal point arrangement that differs between the transmission systems is a combination of one signal point arrangement and a signal point arrangement that prevents signal points from overlapping when the signal point arrangement is rotated. Transmitting device. The transmission apparatus according to claim 1,
The signal point arrangement different between the transmission systems is a combination of one signal point arrangement and a signal point arrangement in which there are signal points that do not overlap when the signal point arrangement is rotated, enlarged, or reduced. A transmitter characterized by the above. A signal for each transmission system transmitted from the transmission device according to claim 1 is combined in a propagation path, the combined signal is received for each reception system, and the original transmission data is restored.
For each reception system, a reception high-frequency unit that receives the synthesized signal via a reception antenna and converts the frequency, and
For each reception system, OFDM modulation is performed on the signal frequency-converted by the reception high-frequency unit when the modulation unit of claim 1 performs OFDM modulation, and single-carrier modulation is performed by the modulation unit of claim 1. If performed, a demodulator that performs single carrier demodulation;
Based on the mapping information of the signal point arrangement with the same modulation multi-level number between the transmission systems used for mapping in the space-time trellis coding unit, but estimated from the signal frequency-converted by the reception high-frequency unit. In addition, a propagation signal response between the plurality of transmission systems and the plurality of reception systems is used to create a reception signal replica for each reception system, and an actual reception demodulated by the reception signal replica and the demodulation unit A Viterbi decoding unit that calculates a metric between the signals, selects a branch based on the metric, creates a trellis diagram, and traces back the trellis diagram to decode the original transmission data. A receiving device. The receiving device according to claim 4,
The signal point arrangement that differs between the transmission systems is a combination of one signal point arrangement and a signal point arrangement that prevents signal points from overlapping when the signal point arrangement is rotated. Receiving device. The receiving device according to claim 4,
The signal point arrangement that differs between the transmission systems is a combination of one signal point arrangement and a signal point arrangement in which there are signal points that do not overlap when the signal point arrangement is rotated, enlarged, or reduced. A receiving device.

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