JP2007096658A - Wireless transmission device and wireless reception device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a data transmission device that increases an interleave size to improve an error correction rate and shortens a demodulation processing time.
A wireless transmission device 10 divides a transmission frame into a plurality of blocks and performs interleaving processing for each block, and the size of each block as an interleaving processing unit is set so that the final block of the transmission frame is included in the transmission frame. And a frame configuration unit 12 that is set to be equal to or smaller than the size of other blocks. The interleave unit 22 performs an interleave process according to the size set by the frame configuration unit 12. The frame configuration unit 12 generates frame configuration information indicating the set block size, and adds the frame configuration information to the transmission frame. The wireless transmission device 10 includes an RF unit 14 and an antenna 16 and transmits a transmission frame to which frame configuration information is added.
[Selection] Figure 1

Description

  The present invention relates to a wireless transmission device and a wireless reception device in wireless communication.

  In conventional wireless communication such as a wireless LAN, a decrease in received power due to fading causes a data transmission error. An error rate deteriorates due to a data transmission error, and communication quality deteriorates. In the conventional wireless communication apparatus, the error rate is improved by encoding the transmission data with an error correction code and correcting the bit on which the data transmission error has occurred on the receiving side.

  Burst error is a phenomenon in which errors occur continuously due to the continued reception power of a value below a certain threshold. The error correction code described above has little effect on burst errors. Interleaving is known as a countermeasure against an increase in error rate due to a burst error. In the interleaving process, adjacent bits of transmission data are replaced with separated bits. As a result, places where reception power is low are dispersed in time, so that burst errors in received data can be prevented, and an error rate can be prevented from increasing by using error correction capability.

Since the received power due to fading varies with time, it is desirable to replace interleaving with bits as far apart as possible. As the interleave size increases, the error rate can be improved. Patent Document 1 discloses a technique for changing the interleave size for each packet by the received power.
JP-A-6-77939

  However, increasing the interleave size increases the processing time required for error correction. In other words, in order to obtain the original data by deinterleaving the interleaved block, it is necessary to wait until the data of the entire interleaved block is received.

  In wireless communication, the transmission timing of an ACK (acknowledgment response) for notifying the transmission side that a frame has been received is specified. For example, “High Speed Physical Layer (PHY) in 5 GHz band” IEEE802.11a 1999 stipulates that an ACK must be returned within a predetermined time limit (16 ms) from the reception of the final data.

  However, if the interleaving size increases and the demodulation process takes time, the time limit for returning an ACK may not be met. If the ACK reply does not meet the time limit, the transmission side repeats the retransmission process. However, reception cannot be completed because the same event occurs in which retransmission of ACK cannot be performed within the time limit during retransmission processing. While there is a demand for improving the communication quality by increasing the interleave size in this way, only an interleave having a size capable of completing the processing by the time limit for ACK reply can be used.

  In view of the above background, an object of the present invention is to provide a wireless transmission device and a wireless reception device that improve the error correction rate by increasing the interleave size and reduce the demodulation processing time.

  The radio transmission apparatus according to the present invention includes an interleave unit that divides a transmission frame into a plurality of blocks and performs interleaving processing for each block, and the size of each block that is an interleaving processing unit. A block size setting unit that sets the size to be equal to or smaller than the size of another block, and a transmission unit that transmits the blocks interleaved by the interleaving unit.

  In this way, by making the size of the interleave block in one transmission frame variable and making the size of the final block smaller than the size of other blocks, the reception processing time of the final block is shortened. Thereby, since the reception processing time is short for the final block, the deinterleaving process can be started quickly, and the time from the reception of the final block of the frame to the completion of the deinterleaving process can be shortened. Since other blocks other than the final block can be increased in interleave size, the error correction rate can be improved.

  In the wireless transmission device, the block size setting unit may set the size of the final block so that the reception processing time of the final block is equal to the deinterleave processing time of the block immediately before the final block. .

  Thus, when the reception processing time of the last block is equal to the deinterleaving processing time of the previous block, the deblocking processing of the last block can be performed immediately after the deinterleaving processing of the previous block is completed.

  In the wireless transmission device, the block size setting unit may set the size so that a plurality of blocks subsequent to the final block have the same size as the final block.

  By including a plurality of blocks having a size smaller than the other blocks in this way, the decoding processing time can be reduced near the final block of the transmission frame without being affected by the block size of other parts of the transmission frame.

  The wireless transmission device further includes a frame configuration information generation unit that generates frame configuration information indicating the block size set by the block size setting unit, and the transmission unit further includes the frame configuration information generation unit. The generated frame configuration information may be transmitted.

  With this configuration, it is possible to notify the receiving side of the size of a block, which is an interleave processing unit, by using frame configuration information.

  The radio transmission apparatus may change the modulation scheme of each block based on the size of the block, and the frame information generation unit may generate frame configuration information including information indicating the modulation scheme.

  Since the size of the final block is equal to or smaller than the size of other blocks in the same frame, the effect of error correction by interleaving is small. If the modulation scheme can be changed for each block and the multi-value ratio of the final block is set to be small, it is possible to compensate for the small error correction effect due to interleaving, and the error of the entire frame can be made constant.

  The radio transmission apparatus may change the coding rate of each block based on the block size, and the frame information generation unit may generate frame configuration information including information indicating the coding rate.

  Since the size of the final block is equal to or smaller than the size of other blocks in the same frame, the effect of error correction by interleaving is small. If the coding rate of the final block is set to be small with a configuration in which the coding rate can be changed for each block, it is possible to compensate for the small error correction effect due to interleaving and to make the error of the entire frame constant.

  The MIMO transmission apparatus of the present invention includes an interleaving unit that divides a transmission frame into a plurality of blocks and performs interleaving processing for each block, and the size of each block that is an interleaving processing unit. A block size setting unit that sets the size to be equal to or smaller than the size of another block, and a transmission unit that transmits the blocks interleaved by the interleaving unit from a plurality of antennas.

  With this configuration, the same effect as that of the wireless transmission device of the present invention can be obtained in the MIMO transmission device. In addition, various configurations of the wireless transmission device of the present invention can be applied to the MIMO transmission device of the present invention.

  The MIMO transmission apparatus further includes a frame configuration information generation unit that generates frame configuration information indicating the block size set by the block size setting unit, and the transmission unit further includes the frame configuration information generation unit. The generated frame configuration information may be transmitted from a plurality of antennas.

  With this configuration, it is possible to notify the receiving side of the size of a block, which is an interleave processing unit, by using frame configuration information.

  The radio reception device of the present invention acquires a plurality of interleaved blocks transmitted from the radio transmission device and a frame that receives frame configuration information related to the blocks, and information indicating the block size from the frame configuration information, A deinterleaving unit that obtains an original frame by deinterleaving a plurality of received blocks based on information indicating the size of the block.

  Thus, by acquiring information indicating the block size from the frame configuration information and performing deinterleaving using the information, data interleaved with different block sizes can be deinterleaved. When a frame in which the size of the final block is set to be equal to or smaller than the other blocks is received, the time from when the final block of the frame is received until the deinterleaving process is completed can be shortened.

  A MIMO receiving apparatus of the present invention is configured to receive a plurality of interleaved blocks transmitted from a radio transmitting apparatus and frame configuration information related to the blocks by a plurality of antennas, and indicate a block size from the frame configuration information A deinterleave unit that obtains information and deinterleaves a plurality of received blocks based on information indicating the size of the block to obtain an original frame, and the frame obtained by the deinterleave unit includes the frame configuration information. A replica generation unit that generates a replica by encoding based on the above, and an interference cancellation unit that cancels interference of a signal received by the reception unit using the replica generated by the replica generation unit.

  With this configuration, the same effect as that of the radio reception apparatus of the present invention can be obtained in the MIMO reception apparatus. Particularly, in the MIMO receiving apparatus, since the number of times of deinterleaving and interleaving for canceling interference by a replica signal is large, the effect of shortening the processing time is great.

  According to the present invention, the reception processing time of the final block is shortened by setting the size of the final block to be equal to or smaller than the size of other blocks, and the time from the reception of the final block of the frame to the completion of the deinterleave processing Since the size of other blocks can be increased, the error correction capability by interleaving can be improved.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
(First embodiment)
FIG. 1 is a block diagram of a wireless transmission device 10 according to the first embodiment of this invention. The wireless transmission device 10 includes a frame configuration unit 12 that configures a transmission frame from data to be transmitted, a modulation unit 20 that modulates the transmission frame, and an RF unit 14 that transmits the modulated transmission frame. Also, the modulation unit 20 includes an error correction coding unit 21 that performs convolutional coding of the transmission frame, an interleaving unit 22 that performs interleaving processing on the transmission frame that has been subjected to error correction coding, and a mapping unit 23 that maps data of the transmission frame. And have.

  The frame configuration unit 12 has a function of setting the size of the interleave block. The frame configuration unit 12 sets the size of the interleave block so that the transmission frame is composed of two types of interleaves having different sizes. Here, the 9 blocks from the beginning of the transmission frame are set to an interleave block having a size of 192 bits, and the subsequent blocks are set to a size of 48 bits. Here, two blocks including the final block are set to 48 bits, but only the final block may be set to 48 bits. Also, the frame configuration unit 12 sets the coding rate and modulation scheme of each block according to the block size. Here, the frame configuration unit 12 sets the coding rate of the 192-bit block to 3/4, the modulation method to QPSK, the coding rate of the 48-bit block to 1/2, and the modulation method to BPSK.

  The frame configuration unit 12 generates frame configuration information including information indicating the size, coding rate, and modulation scheme of each interleave block, and adds the generated frame configuration information before data to be transmitted. The frame configuration unit 12 adds a tail bit to the end of data to be transmitted. The tail bits are 6-bit data consisting of all 0s, for example. The tail bit enables Viterbi decoding on the receiving side with the same performance as the conventional one.

  Here, a transmission frame generated by the frame configuration unit 12 of the present embodiment will be described.

  FIG. 2A is a diagram illustrating a configuration of a transmission frame generated by the frame configuration unit 12. The transmission frame includes frame configuration information, data, and tail bits.

  FIG. 2B is a diagram showing frame configuration information. The frame configuration information includes information on the coding rate, modulation scheme, interleave size, and overall data length of each interleave block, and a tail bit is added at the end. The coding rate 1, the interleave size 1, and the modulation scheme 1 are information on 9 blocks of interleaving from the beginning of the frame. The coding rate 2, the interleave size 2, and the modulation scheme 2 are information regarding the two interleaves at the end of the frame. Note that it is predetermined that the frame configuration information is modulated by a coding rate of 1/2, an interleave size of 48 bits, and a BPSK modulation method. This makes it possible to decode the frame configuration information on the receiving side.

  FIG. 2C is a diagram showing each interleave block constituting the transmission frame. However, frame configuration information is not included. The frame configuration information constitutes an independent interleave block. In the present embodiment, nine 192-bit interleave blocks with a coding rate of 3/4 are continued from the beginning, followed by two 48-bit interleaved blocks with a coding rate of ½. By configuring the interleave blocks constituting one transmission frame with different sizes in this way, it is possible to speed up the processing on the receiving side while improving the error correction rate. This will be described in detail later.

  The frame configuration unit 12 transmits the coding rate, interleave block size, and modulation scheme information included in the generated frame configuration information to the coding rate control unit 24, the interleave size control unit 25, and the modulation scheme control unit 26, respectively. . Accordingly, the coding rate control unit 24, the interleave size control unit 25, and the modulation scheme control unit 26 control the error correction coding unit 21, the interleave unit 22, and the mapping unit 23 according to the conditions set by the frame configuration unit 12. it can.

  Next, the error correction encoding unit 21 will be described. The error correction encoder 21 performs convolutional encoding using a convolutional encoder as shown in FIG. The convolutional encoder holds the input data in a (constraint length-1) stage shift register, and convolves the input data with 2 bits obtained by using the past 6 data values. Output as encoded result.

  The error correction coding unit 21 is controlled by the coding rate control unit 24. The interleave unit 22 is controlled by the interleave size control unit 25. The mapping unit 23 is controlled by the modulation scheme control unit 26. Also, the coding rate control unit 24, the interleave size control unit 25, and the modulation scheme control unit 26 perform control based on the frame configuration information transmitted from the frame configuration unit 12.

  FIG. 4 is a block diagram of the wireless reception device 30 according to the first embodiment of this invention. The wireless reception device 30 according to the present embodiment receives data transmitted from the wireless transmission device 10 shown in FIG. The wireless reception device 30 acquires frame configuration information by decoding an RF unit 32 that receives data, a demodulator 40 that demodulates data received by the RF unit 32, and frame configuration data included in the head of the received data. And a frame configuration decoding unit 34. Further, the demodulating unit 40 includes a demapping unit 41 that demaps received data, a deinterleaving unit 42 that deinterleaves data received by the demapping unit 41 to obtain original data, and a deinterleaving unit 42. And an error correction decoding unit 43 that performs error correction decoding on the restored data.

  The frame configuration decoding unit 34 transmits the decoded frame configuration information to the demodulation scheme control unit 44, the deinterleave size control unit 45, and the coding rate control unit 46. The demodulation method control unit 44 controls the demapping unit 41 based on the frame information transmitted from the frame configuration decoding unit 34. The deinterleave size control unit 45 controls the deinterleave unit 42 based on the frame information transmitted from the frame configuration decoding unit 34. The coding rate control unit 46 controls the error correction decoding unit 43 based on the frame information transmitted from the frame configuration decoding unit 34.

Next, an operation when data transmission is performed by the wireless transmission device 10 and the wireless reception device 30 described above will be described.
First, the frame configuration unit 12 of the wireless transmission device 10 determines the size, coding rate, and modulation scheme of the blocks constituting the transmission frame. Then, the frame configuration unit 12 generates frame configuration information including each determined coding rate, interleave size, and modulation scheme. The frame configuration information includes information indicating the length of transmission data (see FIG. 2B). The frame configuration information may include information indicating how many blocks of each size are included.

  Next, the frame configuration unit 12 adds frame configuration information to the front of the transmission data, adds a tail bit to the end of the transmission data, and completes the transmission frame (see FIG. 2A).

  Subsequently, the error correction encoding unit 21 performs convolution encoding on the transmission data sequence. The coding rate control unit 24 controls the puncturing process of the error correction coding unit based on the frame configuration information. The puncturing process regularly removes bits from the output bit string of the convolutional encoder shown in FIG. The coding rate can be changed by changing the bit cutting ratio. For example, 2 bits out of 6 bits are deleted to make the coding rate 3/4, and 1 bit out of 4 bits is deleted to make the coding rate 2/3.

  Next, the interleaving unit 22 performs an interleaving process for rearranging the data subjected to error correction coding. The interleave size control unit 25 controls the interleave size of the interleave unit 22 based on the frame configuration information. For example, the interleave size can be changed by preparing a plurality of interleaves having different sizes and switching them according to a desired size. Note that the frame configuration information and data are interleaved independently, and the generated interleave block also has an independent configuration.

  Next, the mapping unit 23 modulates the interleaved frame configuration information and data. The modulation scheme control unit 26 controls the modulation scheme of the mapping unit 23 based on the frame configuration information. For example, QPSK and BPSK modulators are prepared in the mapping unit 23 and are switched based on the control information. The RF unit 14 up-converts the modulated frame configuration information and data as a frame and transmits the frame from the antenna 16.

  The wireless reception device 30 receives the frame configuration information and data (frame) transmitted from the wireless transmission device 10 via the antenna 36. The RF unit 32 of the wireless reception device 30 down-converts the received frame configuration information and data. The radio reception device 30 analyzes the frame configuration information added to the head of the transmitted frame by the frame configuration decoding unit 34 before demodulating the data. Since the frame configuration information is modulated with a predetermined coding rate, interleave size, and modulation scheme, it can be decoded.

  The frame configuration decoding unit 34 transmits the read frame configuration information to the demodulation scheme control unit 44, the deinterleave size control unit 45, and the coding rate control unit 46. Accordingly, the demodulation scheme control unit 44, the deinterleave size control unit 45, and the coding rate control unit 46 can perform each process based on the frame configuration information.

  The demapping unit 41 demodulates the data down-converted by the RF unit 32. Thereafter, the deinterleave unit 42 rearranges the data rearranged on the transmission side in the original order. The deinterleave size control unit 45 controls the deinterleave size of the deinterleave unit 42 based on the frame configuration information. For example, the interleave size control unit 45 prepares deinterleavers having different sizes as in the transmission side, and switches and uses them according to the frame configuration information.

The error correction decoding unit 43 performs a depuncture process and a Viterbi decoding process. In the depuncture process, a value having the same likelihood with respect to bit 0 and bit 1 is inserted at the bit location deleted from the data bit string by the puncture process on the transmission side. The coding rate control unit 46 controls the depuncture coding rate based on the decoded frame information. Then, error correction decoding is performed on the data punctured by the Viterbi decoder, and the data is output.
Heretofore, the wireless transmission device 10 and the wireless reception device 30 according to the first embodiment have been described.

  The wireless transmission device 10 according to the first embodiment configures the frame so that the size of the last block of the transmission frame and the previous block are smaller than the sizes of the nine blocks from the beginning. As a result, the error correction rate can be improved and the time from when the frame is received until the ACK is returned can be shortened.

  FIG. 5 is a diagram for explaining the effect of the first embodiment. FIG. 5 is a diagram in which time is taken on the horizontal axis and processing performed on the receiving side in the vertical direction is shown in order from the top. The wireless reception device 30 receives data composed of blocks # 1 to # 11 (S1). The sizes of blocks # 1 to # 9 are 192 bits, and the sizes of blocks # 10 and # 11 are 48 bits.

  The demapping unit 41 of the wireless reception device 30 performs demodulation processing on received data (S2). Since the demodulation processing is performed in the order in which the received signals are received, the demodulation processing output is output with a delay of the processing delay time t1.

  Next, the deinterleaving unit 42 of the wireless reception device 30 performs a deinterleaving process on the demodulated data (S3). In the deinterleaving process, since the data series for the interleave size is rearranged and output, the rearranged data can be output only after the data for the interleave size is once accumulated. Accordingly, the processing by the deinterleave unit 42 is started when the demodulation of all the data of each interleave block is completed. Therefore, a delay of time t2 occurs due to the deinterleaving process.

  Subsequently, the error correction decoding unit 43 of the wireless reception device 30 performs Viterbi decoding processing on the deinterleaved data (S4). Since the Viterbi decoding process is performed after the completion of the deinterleave process, a delay of time t3 occurs. In order to obtain sufficient accuracy in the Viterbi decoding process, it is necessary to ensure a traceback length several times the constraint length. Therefore, in order to complete Viterbi decoding of data of one interleave size, data of the first part of the next deinterleaver is required. For this reason, when the next deinterleaving process is completed and the output data is not input to the Viterbi decoder, the bits after the deinterleaved output cannot complete the Viterbi decoding, and the Viterbi decoding process is interrupted. As a result, the Viterbi decoding process is interrupted for a time t4, and the process is delayed. The reason why the deinterleaving process can be performed in a shorter time than the reception process and the demodulation process is because the data once stored is processed.

  As described above, there is a delay of time t5 between the completion of the reception process (S1) of interleave block # 1 and the completion of the Viterbi decoding process (S4). Assuming that the final interleave block # 11 of the transmission frame has the same size as the interleave block # 1, the final interleave block # 11 is also processed from the completion of the reception process (S1) to the completion of the Viterbi decoding process (S4). A delay of time t5 occurs. When the delay time t5 is longer than the time limit for transmitting an ACK, the transmission of the ACK is delayed, so that the same transmission frame is retransmitted from the wireless transmission device 10.

  In this embodiment, since the sizes of the last two interleave blocks are reduced, the delay time from the completion of the transmission frame reception process (S1) to the completion of the Viterbi decoding process (S4) can be shortened. .

  Since the interleave block # 10 is smaller than the interleave block # 9, the reception and decoding process (S1, S2) of the interleave block # 10 is completed during the deinterleave process (S3) of the interleave block # 9. Therefore, when the interleave block # 9 is Viterbi-decoded, the deinterleave process (S3) for the next interleave block # 10 is completed. In the Viterbi decoding process (S4) of the data of the interleave block # 9, the processing waiting time corresponding to the time t4 can be eliminated, and the Viterbi decoding result can be obtained quickly. By reducing the processing waiting time, the Viterbi decoding of the interleave blocks # 10 and # 11 can be completed quickly. The processing time t6 from the completion of the final frame reception process (S1) to the completion of the Viterbi decoding process (S4) can be shortened from the processing delay time t5 of the large block.

  Therefore, according to the wireless transmission device 10 and the wireless reception device 30 of the present embodiment, the processing time from the completion of reception to the completion of decoding can be shortened, so that the system that returns an ACK notifying the transmission side that the frame has been received. Even in this case, ACK can be transmitted within the time limit defined by the communication protocol. Also, except for the last block, a large-sized block can be used as a processing unit for interleaving processing, so that reception performance can be improved.

  Further, in the present embodiment, a modulation scheme and a coding rate that are more robust than a block having a large interleave size are adopted as a modulation scheme and a coding rate of a block having a small interleave size (see FIG. 2B). Thereby, the reception performance of a block having a small interleave size is improved to the same level as the reception performance of a block having a large interleave size, so that the reception performance of the entire frame can be made uniform and the frame error rate can be reduced.

  In this embodiment, the case where frame configuration information is included in a frame to be transmitted together with data has been described. However, the interleave size, coding rate, and modulation scheme are determined in advance by both the transmission device and the reception device. Frame configuration information does not have to be included in the frame.

  In the present embodiment, the convolutional code is used as the error correction code. However, the present invention is not limited to this, and a block code such as an LDPC code may be used. A block code can be applied by the apparatus having the configuration shown in FIGS. 12 has a configuration in which the error correction encoding unit 21 and the interleaving unit 22 of FIG. 1 are replaced with a block encoding unit 27, and the interleave size control unit 25 is replaced with a block size control unit 28. . The radio reception apparatus 30 shown in FIG. 13 has a configuration in which the deinterleave unit 42 and the error correction decoding unit 43 in FIG. 4 are replaced with a block code decoding unit 47, and the deinterleave size control unit 45 is replaced with a block size control unit 48. Have. The block code decoding unit 47 is equivalent to simultaneously performing the deinterleaving process (s3) and the Viterbi decoding process (s4) shown in FIG. Therefore, the same effect can be obtained even when a block code is used.

(Second Embodiment)
Next, MIMO transmitting apparatus 50 and MIMO receiving apparatus 60 according to the second embodiment of the present invention will be described. The MIMO transmitter 50 and the MIMO receiver 60 of the second embodiment perform MIMO wireless communication.

  FIG. 6 is a diagram illustrating the MIMO transmission apparatus 50 and the MIMO reception apparatus 60 according to the second embodiment. The MIMO transmission apparatus 50 has two transmission antennas 16, and the MIMO reception apparatus 60 has two reception antennas 36. The number of antennas 16 and 36 in the present embodiment is an example, and the number of transmission / reception antennas 16 and 36 is not limited to two, and may be three or more.

  FIG. 7 is a diagram illustrating a configuration of the MIMO transmission apparatus 50. The MIMO transmission apparatus 50 includes a serial / parallel conversion unit 18, a frame configuration unit 12, a modulation unit 20, and an RF unit 14. The configurations of the frame configuration unit 12, the modulation unit 20, and the RF unit 14 are the same as the configuration of the wireless transmission device 10 according to the first embodiment.

  The serial / parallel converter 18 performs serial / parallel conversion on the input data and outputs two stream data. The frame configuration unit 12 determines a coding rate, an interleave size, and a modulation scheme, and outputs frame configuration information.

  The modulation unit 20 includes an error correction coding unit 21, an interleaving unit 22, a mapping unit 23, a coding rate control unit 24, an interleave size control unit 25, and a modulation scheme control unit 26. The coding rate control unit 24 generates a coding rate control signal based on the frame configuration information, and inputs the coding rate control signal to the error correction coding unit 21. The interleave size control unit 25 generates an interleave control signal based on the frame configuration information, and inputs the interleave control signal to the interleave unit 22. The modulation scheme control unit 26 generates a modulation scheme control signal and inputs the modulation scheme control signal to the mapping unit 23.

  The error correction coding unit 21 performs coding on the data stream st1 based on the coding rate control signal and outputs the coded data. The interleaving unit 22 performs interleaving on the encoded data and outputs the interleaved data. The mapping unit 23 performs BPSK modulation, QPSK modulation, and multilevel modulation on the interleaved data based on the modulation scheme control signal, and outputs a modulated signal.

  The RF unit 14 performs processing such as frequency conversion and amplification on the modulated signal and outputs a transmission signal. The antenna 16 transmits a transmission signal from the RF unit 14 as a radio signal. The same processing as described above is performed on the data stream st2, and a radio signal is transmitted from the antenna 16.

  FIG. 8 is a diagram illustrating a MIMO receiver 60 that demodulates a signal transmitted from the MIMO transmitter 50. As shown in FIG. 8, the MIMO receiving apparatus 60 includes two receiving antennas 36, an RF unit 32, a signal separation unit 38, a primary demodulation unit 70, and a secondary demodulation unit 80. The RF unit 32 performs frequency conversion, amplification, etc. on the signal received by the receiving antenna 36, and outputs a baseband signal.

  The signal separation unit 38 performs A / D conversion, channel estimation, frequency compensation, signal separation, and the like on the baseband signal input from the RF unit 32, and outputs the separated signal and frame configuration information. As the separation method, methods such as ZF (Zero Forcing) and MMSE (Minimum Mean Square Error) can be considered.

  The primary demodulator 70 receives the separated signals as inputs, demodulates the signals of the respective streams, and outputs primary demodulated data. The secondary demodulator 80 receives the primary demodulated data and the baseband signal, cancels the interference signal using a replica signal obtained by remodulating the baseband signal and the primary demodulated data, and outputs the secondary demodulated data.

  FIG. 9 is a diagram illustrating a detailed configuration of the primary demodulation unit 70 of the MIMO receiving apparatus 60. The primary demodulation unit 70 includes a demodulation unit 40 and a frame configuration decoding unit 34. The demodulator 40 and the frame configuration decoder 34 have the same configuration as that of the wireless reception device 30 according to the first embodiment. The demodulation unit 40 includes a demapping unit 41, a deinterleave unit 42, an error correction decoding unit 43, a demodulation scheme control unit 44, a deinterleave size control unit 45, and a coding rate control unit 46.

  The frame configuration decoding unit 34 decodes the frame configuration information from the received decoded data and outputs the frame configuration information. The frame configuration information is the same as that described in the first embodiment (see FIG. 2B). Since the frame configuration information is modulated with a predetermined coding rate, interleave size, and modulation method, the frame configuration decoding unit 34 can decode the frame configuration information.

  The demodulation method control unit 44 generates a demodulation method control signal based on the frame configuration data input from the frame configuration decoding unit 34, and inputs the generated demodulation method control signal to the demapping unit 41. The demapping unit 41 converts the signal separation signal st1 into demapping data based on the demodulation scheme control signal, and outputs the demapping data.

  The deinterleave size control unit 45 inputs a deinterleave control signal to the deinterleave unit 42 based on the frame configuration information input from the frame configuration decoding unit 34. The deinterleave unit 42 performs deinterleave processing on the demapping data input from the demapping unit 41 based on the deinterleave control signal, and outputs deinterleave data.

  The coding rate control unit 46 determines the coding rate based on the frame configuration information input from the frame configuration decoding unit 34, and inputs the coding rate control signal to the error correction decoding unit. The error correction decoding unit 43 performs error correction decoding on the deinterleaved data input from the deinterleaving unit 42 based on the coding rate control signal, and outputs decoded data.

  FIG. 10 is a diagram showing a detailed configuration of the secondary demodulation unit 80 of the MIMO receiving apparatus 60. The secondary demodulation unit 80 remodulates the primary demodulated data, an interference canceller 82 that generates a replica from the remodulated data and cancels interference of received data, and reception in which the interference is canceled And a re-demodulation unit 40 that further demodulates the data. The remodulation unit 20 is the same as the configuration of the modulation unit 20 of the wireless transmission device 10 of the first embodiment, and the redemodulation unit 40 is the configuration of the demodulation unit 40 of the wireless reception device 30 of the first embodiment. Is the same.

  The remodulator 20 includes an error correction encoder 21, an interleaver 22, a mapping unit 23, a coding rate controller 24, an interleave size controller 25, and a modulation scheme controller 26. The remodulation unit 20 performs the same remodulation processing as the transmission side on the primary demodulated data input from the primary demodulation unit 70 based on the frame configuration information, and outputs a modulated signal.

  The interference canceller 82 receives the received baseband signal and the re-demodulated signal, performs a process of subtracting a replica signal created using the re-demodulated signal from the received baseband signal, and outputs an interference cancellation signal.

  The re-demodulation unit 40 includes a demapping unit 41, a deinterleave unit 42, an error correction decoding unit 43, a demodulation scheme control unit 44, a deinterleave size control unit 45, and a coding rate control unit 46. The re-demodulation unit 40 performs a demodulation process similar to that of the demodulation unit 40 of the primary demodulation unit 70. The re-demodulation unit 40 receives the interference cancellation signal and the frame configuration information, performs the same processing as the demodulation unit 40 of the primary demodulation unit 70, and outputs demodulated data. The reception baseband signal st2 is processed by the same method as described above, and secondary demodulated data is output.

  FIG. 11 is a diagram illustrating a flow of reception processing by the MIMO receiving apparatus 60 according to the second embodiment. The primary demodulation process from frame reception to Viterbi decoding is the same as in the first embodiment. In the MIMO receiving apparatus 60 of the second embodiment, the secondary demodulation process is performed following the primary demodulation process. That is, the MIMO receiving apparatus 60 performs re-modulation using the Viterbi-decoded Viterbi demodulated data. Viterbi demodulated data is sequentially input to the error correction encoder 21 and the encoded data is output (S5). Since the error correction coding unit 21 can process the input data in order, the processing delay until the encoded data output is small.

  Next, the remodulation unit 20 performs an interleaving process on the encoded data (S6). The interleave unit 22 temporarily stores data for the interleave size and then outputs the data after rearranging the order. Accordingly, the output of the interleaving process is delayed by the time t7 corresponding to the interleave size.

  The interleaved data is subjected to mapping processing (S7) and interference cancellation processing (S8), and is input to the re-demodulation unit 40. The re-demodulation unit 40 performs demapping processing on the reception data that has been subjected to interference cancellation processing (S9). Since the mapping process (S7), the interference cancellation process (S8), and the demapping process (S9) can process the input data in order, the processing delay until each output is small. The re-demodulation unit 40 deinterleaves the demapped data (S10). In the deinterleaving process, input data for an interleave size is temporarily stored, and then the input data is rearranged and output. Accordingly, in the deinterleave process, a delay of time t8 corresponding to the interleave size occurs from the input to the Viterbi decoding output.

  Subsequently, the re-demodulation unit 40 performs Viterbi decoding processing on the deinterleaved data (S11). Due to the characteristics of Viterbi decoding, it is necessary to input data about five times the constraint length in order to output the data. Therefore, the data cannot be output until the deinterleaving process for the next interleave size is completed. A delay of time t10 occurs until the deinterleaving process is completed.

  As described above, in the MIMO receiving apparatus 60 of the second embodiment, the received data is encoded to generate a replica signal, and the replica signal is subtracted to cancel the interference, and then the decoding is performed again. In the MIMO receiving apparatus 60, the delay time caused by interleaving and deinterleaving increases as the number of times of encoding and decoding increases.

  In the second embodiment, similarly to the first embodiment, the delay time caused by multiple deinterleaving and interleaving can be shortened by reducing the size of the last block, so that the demodulation processing time Can be greatly shortened.

  The wireless transmission device and the wireless reception device of the present invention have been described in detail above with reference to the embodiments. However, the present invention is not limited to the above embodiments.

  For example, although the single carrier scheme has been described in the above-described embodiment, a multicarrier scheme may be used.

  In addition, the coding rate and the modulation scheme of each interleave block in the above-described embodiment are examples, and the coding rate and the modulation scheme may be different from those in the above-described embodiment.

  In the above-described embodiment, an example in which a transmission frame is divided into two types of interleave blocks has been described. However, a transmission frame may be divided into three or more types of interleave blocks.

  In the embodiment described above, the last two blocks are small blocks having a size smaller than the first to middle blocks, but the number of small blocks is not limited to two. The small block may be one at the end or three or more. When only the last block is a smaller block than the other blocks, the processing time for receiving the last block is equal to the processing time for deinterleaving the previous block. The size is preferable. Thereby, since the deinterleaving of the last block following can be performed simultaneously with the end of the deinterleaving of the immediately preceding block, the delay time of the deinterleaving process can be eliminated.

  The present invention has an excellent effect of improving the error correction rate and shortening the time from the reception of the final block of a frame to the completion of the deinterleaving process. Etc. are useful.

The figure which shows the structure of the radio | wireless transmitter of 1st Embodiment. (A) Diagram showing transmission frame format (b) Diagram showing frame configuration information (c) Diagram showing interleave block constituting transmission frame Diagram showing convolutional encoder The figure which shows the structure of the radio | wireless receiver of 1st Embodiment The figure explaining the reception processing delay time in a wireless receiver The figure which shows the MIMO transmission apparatus and MIMO reception apparatus of 2nd Embodiment The figure which shows the structure of a MIMO transmitter. The figure which shows schematic structure of a MIMO receiver. The figure which shows the structure of a primary demodulation part The figure which shows the structure of a secondary demodulation part The figure explaining the reception processing delay time in a MIMO receiver The figure which shows the modification of the radio | wireless transmitter of 1st Embodiment. The figure which shows the modification of the radio | wireless receiver of 1st Embodiment

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Radio transmitter 12 Frame structure part 14 RF part 16 Antenna 18 Serial-parallel conversion part 20 Modulation part 21 Error correction encoding part 22 Interleaving part 23 Mapping part 24 Coding rate control part 25 Interleave size control part 26 Modulation system control part 27 Block encoding unit 28 Block size control unit 30 Wireless receiver 32 RF unit 34 Frame configuration decoding unit 36 Antenna 38 Signal separation unit 40 Demodulation unit 41 Demapping unit 42 Deinterleaving unit 43 Error correction decoding unit 44 Demodulation method control unit 45 Interleave size controller 46 Coding rate controller 47 Block code decoder 48 Block size controller 50 MIMO transmitter 60 MIMO receiver 70 Primary demodulator 80 Secondary demodulator 82 Interference canceller

Claims (10)

An interleaving unit that divides a transmission frame into a plurality of blocks and performs interleaving processing for each block;
A block size setting unit configured to set the size of each block serving as an interleave processing unit so that the final block of the transmission frame is equal to or smaller than the size of other blocks in the transmission frame;
A transmission unit for transmitting the blocks interleaved by the interleaving unit;
A wireless transmission device comprising:   The radio transmission apparatus according to claim 1, wherein the block size setting unit sets the size of the final block so that the reception processing time of the final block is equal to the deinterleaving processing time of the block immediately before the final block. .   The radio transmission apparatus according to claim 1, wherein the block size setting unit sets a size such that a plurality of blocks subsequent to the final block have the same size as the final block. A frame configuration information generation unit that generates frame configuration information indicating the block size set by the block size setting unit;
The wireless transmission device according to claim 1, wherein the transmission unit further transmits the frame configuration information generated by the frame configuration information generation unit. Changing the modulation scheme of each block based on the size of the block;
The radio transmission apparatus according to claim 4, wherein the frame information generation unit generates frame configuration information including information indicating the modulation scheme. Changing the coding rate of each block based on its block size;
The radio transmission apparatus according to claim 4, wherein the frame information generation unit generates frame configuration information including information indicating the coding rate. An interleaving unit that divides a transmission frame into a plurality of blocks and performs interleaving processing for each block;
A block size setting unit configured to set the size of each block serving as an interleave processing unit so that the final block of the transmission frame is equal to or smaller than the size of other blocks in the transmission frame;
A transmitting unit that transmits blocks interleaved by the interleaving unit from a plurality of antennas;
A MIMO transmitter comprising: A frame configuration information generation unit that generates frame configuration information indicating the block size set by the block size setting unit;
The MIMO transmission apparatus according to claim 7, wherein the transmission unit further transmits the frame configuration information generated by the frame configuration information generation unit from a plurality of antennas. A plurality of interleaved blocks transmitted from the wireless transmission device and a reception unit that receives frame configuration information related to the blocks;
A deinterleaving unit that obtains information indicating the size of a block from the frame configuration information, and obtains an original frame by deinterleaving a plurality of received blocks based on the information indicating the size of the block;
A wireless receiver comprising: A plurality of interleaved blocks transmitted from the wireless transmission device and a receiving unit that receives frame configuration information related to the blocks by a plurality of antennas;
A deinterleaving unit that obtains information indicating the size of a block from the frame configuration information, and obtains an original frame by deinterleaving a plurality of received blocks based on the information indicating the size of the block;
A replica generation unit that generates a replica by encoding the frame obtained by the deinterleaving unit based on the frame configuration information;
Using the replica generated by the replica generation unit, an interference cancellation unit for canceling interference of the signal received by the reception unit,
A MIMO receiver comprising:

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