JP2015050541A - Interleaving device, de-interleaving device, interleaving method and de-interleaving method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a technique for suppressing a reduction in frame use efficiency even if executing inter-frame interleaving.SOLUTION: An inter-frame interleaving memory section 38 inputs M frames (M is an integer of two or greater) of data. An inter-frame interleaving section 34 executes inter-Nth-frame (N is an integer of two or greater) interleaving on the input M frames of data. The inter-frame interleaving section 34 divides the input M frames of data into single frames of data and then divides each frame of data by N to generate M×N blocks, and distributes the N blocks included in every single one of the M frames among N frames. A modulation section 40 outputs M frames of inter-Nth-frame-interleaved data.

Description

  The present invention relates to a communication technique, and more particularly to an interleaving device, a deinterleaving device, an interleaving method, and a deinterleaving method that rearrange the order of data.

  In a mobile radio communication system, a random error or a burst error may occur in a transmission code due to the influence of fading that occurs in a radio transmission path. The encoded signal in which this code error has occurred cannot be decoded and output as it is. Therefore, conventionally, the transmission code is transmitted after error correction coding on the transmission side, and the reception transmission code is subjected to error correction decoding on the reception side. As a result, it is possible to effectively improve the deterioration of quality due to the random error among the random error and the burst error.

  On the other hand, burst errors among the random errors and burst errors are dealt with by using an interframe interleaving method. Interframe interleaving is a method in which encoded data for one frame encoded by an encoder is divided into a plurality of transmission frames and transmitted, so that even if a burst error occurs in any transmission frame, other transmission frames By decoding the data after error correction decoding using the same encoded data inserted into the original data, the original data can be reliably reproduced (see, for example, Patent Document 1).

JP-A-5-22237

  By performing inter-frame interleaving, the frame utilization efficiency decreases. Therefore, it is desired to suppress a decrease in frame utilization efficiency.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide a technique for suppressing a decrease in frame use efficiency even when interframe interleaving is performed.

  In order to solve the above-described problem, an interleaving apparatus according to an aspect of the present invention includes an input unit that inputs data for M (M is an integer of 2 or more) frames, and data for M frames that are input in the input unit. And an inter-frame interleaving unit that performs inter-frame interleaving (N is an integer of 2 or more) and an output unit that outputs data for M frames interleaved between N frames in the inter-frame interleaving unit. The interframe interleaving unit divides the data for M frames input in the input unit into data for each frame, and then divides the data of each frame into N, thereby generating an M × N block. Within a frame, N blocks included in one frame are distributed into N frames.

  Another aspect of the present invention is a deinterleave device. This apparatus inputs data which is data for M (M is an integer of 2 or more) frames and which is interleaved between N (N is an integer of 2 or more) frames, and is input at the input unit. An inter-frame deinterleaving unit that performs inter-N frame deinterleaving for M frames of data and an output unit that outputs data for M frames deinterleaved between N frames in the inter-frame deinterleaving unit. In the data for M frames input at the input unit, the data for M frames before interleaving between N frames is divided into data for each frame, and then the data for each frame is divided into N, thereby M × N. A block is generated, and N blocks included in one frame are distributed in N frames in the M frame.

  Yet another aspect of the present invention is an interleaving method. This method includes a step of inputting data for M (M is an integer of 2 or more) frames, and a step of performing interleaving between N (N is an integer of 2 or more) frames for the input data of M frames. And outputting data for M frames interleaved between N frames. The executing step divides the input M frames of data into data for each frame, and then divides each frame of data into N to generate M × N blocks. N blocks included in one frame are distributed over N frames.

  Yet another aspect of the present invention is a deinterleaving method. This method includes the steps of inputting data for M (M is an integer of 2 or more) frames and interleaved between N (N is an integer of 2 or more) frames, and for the input M frames The method includes a step of performing deinterleaving between N frames on data and a step of outputting data for M frames deinterleaved between N frames. In the data for M frames input in the input step, M × N is obtained by dividing the data for M frames before interleaving between N frames into data for each frame and then dividing the data of each frame into N. Are generated, and N blocks included in one frame are distributed in N frames in the M frame.

  It should be noted that any combination of the above-described constituent elements and a conversion of the expression of the present invention between a method, an apparatus, a system, a recording medium, a computer program, etc. are also effective as an aspect of the present invention.

  According to the present invention, it is possible to suppress a decrease in frame use efficiency even when inter-frame interleaving is performed.

FIGS. 1A and 1B are diagrams showing an outline of inter-frame interleaving processing to be compared in the embodiment of the present invention. It is a figure which shows the structure of the communication system which concerns on the Example of this invention. FIGS. 3A to 3E are diagrams showing an outline of inter-frame interleaving processing and inter-frame de-interleaving processing in the communication system of FIG. FIGS. 4A and 4B are diagrams comparing the interframe interleaving according to the present embodiment and the interframe interleaving according to the comparison target. 3 is a flowchart showing a processing procedure of interframe interleaving by the transmission apparatus of FIG. 2. 3 is a flowchart showing a processing procedure of interframe deinterleaving by the receiving apparatus of FIG. 2.

  Before describing the present invention specifically, an outline will be given first. Embodiments of the present invention relate to a communication system including a transmission device that performs interframe interleaving and a reception device that performs interframe deinterleaving. Although details will be described later, in the inter-frame interleaving so far, it has been necessary to transmit useless data in accordance with the number of frames to be interleaved. For example, in the case of interleaving between three frames, the first frame is 2/3 empty, the second frame is 1/3 empty, the last second frame is 1/3 empty, and the last frame is 2 Since there is a / 3 space, it is necessary to add two frames as the number of frames to be transmitted. Furthermore, as the number of frames to be interleaved increases, the number of frames to be added increases, and the frame utilization efficiency deteriorates. As described above, even when inter-frame interleaving is performed, it is desired to suppress a decrease in frame use efficiency.

The transmitting apparatus according to the present embodiment inserts data to be included in a part of the last frame into an empty part of the first frame. For example, in the case of interleaving between two frames, 1/2 data included in the last frame is inserted into the empty portion of the first frame.
Thus, since redundant data is not transmitted, it is possible to increase transmission efficiency and reduce power consumption. Furthermore, since encoded data is distributed between the last frame and the first frame, the interleaving distance becomes longer, so that the performance can be improved as compared with the normal interframe interleaving.

  FIGS. 1A to 1B show an outline of inter-frame interleaving processing to be compared in the embodiment of the present invention. FIG. 1A shows data before interframe interleaving. Here, as an example, a case where interframe interleaving is performed on data for 16 frames is shown. The horizontal axis indicates time, and the first “1 frame” to the last “16 frame” are arranged in order. Further, the data included in one frame is divided into the number of interframe interleaving “3”. Here, each of 1 frame, 2 frames, 3 frames, 4 frames,... Is (1-1, 1-2, 1-3), (2-1, 2-2, 2-3), (3 -1,3-2,3-3), (4-1,4-2,4-3),. “1-1” or the like is called a block.

  FIG. 1B shows data after interframe interleaving. Three blocks included in one frame before inter-frame interleaving are inserted in three adjacent frames. For example, the first frame is included over 1 frame (1-1, x, x), 2 frames (2-1, 1-2, x), and 3 frames (3-1, 2-2, 1-3). . Here, “x” is data that is not used in particular, and indicates dummy data. As shown in FIG. 1B, by performing interframe interleaving, the number of frames is increased from the number of frames before interframe interleaving. For example, in the case of interleaving between 3 frames, the number of frames increases by 2 and the original 16 frames become 18 frames. Furthermore, as the number of interleaved frames increases, the number of frames increases.

  FIG. 2 shows a configuration of the communication system 100 according to the embodiment of the present invention. The communication system 100 includes a transmission device 10, a communication path 70, and a reception device 20. The transmission device 10 includes transmission data 30, an encoding unit 32, an interframe interleaving unit 34, an interframe interleaving control unit 36, an interframe interleaving memory unit 38, and a modulation unit 40, and the receiving device 20 includes a demodulation unit 50, a frame It includes an inter-deinterleave unit 52, an inter-frame deinterleave control unit 54, an inter-frame deinterleave memory unit 56, a decoding unit 60, and received data 62.

  The transmission data 30 is data to be transmitted. The transmission data 30 is input to the encoding unit 32. The encoding unit 32 receives the transmission data 30. The encoding unit 32 performs encoding on the transmission data 30. An example of encoding is convolutional encoding or LDPC (Low Density Parity Check) encoding. When performing LDPC encoding, the encoding unit 32 adds a parity bit to the transmission data 30. Such encoding is performed on a frame basis. The encoding unit 32 outputs the encoded transmission data 30 (hereinafter referred to as “encoded data”) to the inter-frame interleave memory unit 38.

  The inter-frame interleave memory unit 38 receives encoded data from the transmission data 30. Here, encoded data for M (M is an integer of 2 or more) frames is input. The inter-frame interleave memory unit 38 stores encoded data for one packet. One packet consists of 16 frames. The inter-frame interleaving control unit 36 instructs the inter-frame interleaving memory unit 38 that stores data for one packet to output a block near the last frame to the inter-frame interleaving unit 34. The number of blocks to be output depends on the number of interleaved frames. Here, as an example, a case of interleaving between three frames will be described.

  The interframe interleaving control unit 36 causes the interframe interleaving unit 34 to output the blocks included in the 15th and 16th frames to the interframe interleaving unit 34 first. Next, the inter-frame interleave control unit 36 causes the inter-frame interleave memory unit 38 to output the first frame block and the second frame block to the inter-frame interleave unit 34 in order. Further, the inter-frame interleave control unit 36 sequentially reads the third frame, the fourth frame,..., The 15th frame and the 16th frame, and outputs them to the inter-frame interleave unit 34.

  Thus, the interframe interleave control unit 36 reads the encoded data from the interframe interleave memory unit 38 and outputs it to the interframe interleave unit 34 according to the number of frames to be interleaved. Particularly, in the case of N (N is an integer of 2 or more) interframe interleaving, the interframe interleaving control unit 36 determines that the block included in the N-1 frame counted from the last frame is greater than the block included in the first frame. Instruct to output to the inter-frame interleaving unit 34 first. Further, the interframe interleaving control unit 36 instructs the interframe interleaving unit 34 to reread the blocks included in the N−1 frame from the last frame.

  The inter-frame interleaving unit 34 performs N (N is an integer of 2 or more) inter-frame interleaving on the encoded data for M frames stored in the inter-frame interleaving memory unit 38. Here, in inter-frame interleaving, M × N blocks are generated by dividing M frames of data into data for each frame and then dividing each frame of data into N pieces. The interframe interleaving unit 34 distributes N blocks included in one frame into N frames in the M frame. More specifically, the inter-frame interleaving unit 34 distributes N blocks included in the top frame one by one from the frame to the (N−1) th frame. Further, the interframe interleaving unit 34 repeats the dispersion for the blocks included in the subsequent frames, thereby arranging the blocks out of the Mth frame from the head to the (N-1) th frame. That is, the last block is inserted into an empty part such as the first frame. It can be said that the empty block not used in the first frame is filled with the block of the 15th frame or the block of the 16th frame in advance to eliminate the empty space in the frame. As a result, dummy data becomes unnecessary.

  3A to 3E show an outline of inter-frame interleaving processing and inter-frame de-interleaving processing in the communication system 100. FIG. FIG. 3A shows encoded data after the first inter-frame interleaving. The data in the 15th frame is interleaved between 15-1 in 15th frame, 15-2 in 16th frame, and 15-3 in 1st frame. FIG. 3B shows encoded data for which the N-th process has been completed. As shown by a round broken line in FIG. 3B, the encoded data after interleaving for one frame is filled with 1-1, 16-2, and 15-3. FIG. 3C shows a state in which interleaving is completed up to 16 frames per packet. The encoded data of the 16th frame is filled with 16-1, 15-2, and 14-3. Returning to FIG.

  The modulation unit 40 converts the data output from the inter-frame interleaving unit 34 into symbol data, performs predetermined modulation, and transmits the data. That is, the modulation unit 40 transmits encoded data for M frames interleaved between N frames in the interframe interleaving unit 34. The modulated signal is frequency-converted to a radio frequency signal and then transmitted to the communication path 70.

  The receiving device 20 receives a signal from the transmitting device 10 via the communication path 70. Here, the receiving device 20 executes a process opposite to the process in the transmitting device 10. The demodulator 50 demodulates the received modulation symbol and extracts data from the demodulated symbol. The extracted data is data for M frames and interleaved between N frames. The inter-frame deinterleaving unit 52 performs N inter-frame deinterleaving on the M frames of data input in the demodulation unit 50. The inter-frame deinterleaving process is a process opposite to the inter-frame interleaving process in the inter-frame interleaving unit 34. The inter-frame deinterleave memory unit 56 stores the data from the inter-frame deinterleave unit 52 in response to an instruction from the inter-frame deinterleave control unit 54.

  The interframe deinterleave control unit 54 instructs to store the data of the interframe deinterleave unit 52 in the interframe deinterleave memory unit 56. Here, the reason for storing the data in the inter-frame deinterleave memory unit 56 is, for example, in the case of inter-frame interleaving, in the received first frame, a 15-frame block (15-3) and a 16-frame block (16-2). This is because the block (16-3) of the 16th frame is mixed in the received second frame. Therefore, the 15-frame block (15-3) and 16-frame block (16-2, 16-3) of the received first frame and the received second frame are stored in the inter-frame deinterleave memory unit 56.

  Since the block of the first frame is interleaved over 1 frame (1-1), 2 frames (1-2), and 3 frames (1-3), inter-frame deinterleaving is completed up to 3 frames. Thus, the blocks (1-1, 1-2, 1-3) of the first frame are prepared. The interframe deinterleave control unit 54 notifies the decoding unit 60 of this fact. The inter-frame deinterleave control unit 54 notifies the decoding unit 60 from the next frame every time the inter-frame deinterleave is completed. The inter-frame deinterleave control unit 54 deinterleaves the received block of the 16th frame and notifies the decoding unit 60 of the 14th frame (14-1, 14-2, 14-3).

  Subsequently, the inter-frame deinterleave control unit 54 reads the 15-frame block (15-3) stored in the inter-frame deinterleave memory unit 56 stored earlier, and receives the received 15 frame (15-1) and the received frame (15-1). The decoding unit 60 is notified when the block (15-1, 15-2, 15-3) of the 15th frame is prepared together with the processing result of the interframe deinterleaving unit 52 of the 16 frames (15-2). The inter-frame deinterleaving control unit 54 reads the 16-frame block (16-2, 16-3) from the inter-frame deinterleaving memory unit 56 in the same process, and receives the received 16 frames (16-2, 16-3). When the block (16-1, 16-2, 16-3) of the 16th frame is prepared together with the processing result of the interframe deinterleaving unit 52 of 16-1), the decoding unit 60 is notified.

  FIG. 3D shows received data at the time when the inter-frame deinterleaving of 3 frames is completed. As indicated by the broken line, when the inter-frame deinterleaving for three frames is completed, the data (1-1, 1-2, 1-3) of the first frame are aligned and the decoding process can be performed. FIG. 3E shows received data when the number of inter-frame deinterleaving is within the remaining N−1 frames. Since the data necessary for decoding is not available, the block of the 15th and 16th frames stored is read from the memory, and the received 15 frames (15-1) and the received 16 frames (15-2) The 15th frame (15-1, 15-2, 15-3) is aligned with the result of the deinterleaving process. Returning to FIG.

  The decoding unit 60 executes Viterbi decoding processing and LDPC decoding processing in accordance with the encoding method in the encoding unit 32. The decoding unit 60 outputs the decoding result as received data 62. That is, the decoding unit 60 outputs data for M frames deinterleaved for N frames in the interframe deinterleaving unit 52.

  This configuration can be realized in terms of hardware by a CPU, memory, or other LSI of any computer, and in terms of software, it can be realized by a program loaded in the memory, but here it is realized by their cooperation. Draw functional blocks. Accordingly, those skilled in the art will understand that these functional blocks can be realized in various forms by hardware only, software only, or a combination thereof.

  FIGS. 4A and 4B are diagrams comparing the interframe interleaving according to the present embodiment and the interframe interleaving according to the comparison target. Here, the transmission data of the first frame after inter-frame interleaving is compared. The number of bits in one frame is 348, and if each bit is A-B, A indicates what frame of encoded data, and B indicates what bit of encoded data. For example, if it is 16-13b, it becomes the 13th bit encoded data of the 16th frame. Inter-frame interleaving is performed by interleaving 12 columns and 29 rows over 3 frames. FIG. 4A shows a case where inter-frame interleave data according to this embodiment is applied. When arranged in the order of transmission direction, 1-1b, 16-13b, 15-25b, 1-37b,... , 1-336b, 16-348b, and no dummy data is included. On the other hand, FIG. 4B shows a case of comparison, and similarly, when arranged in the order of transmission data, 1-b, x, x, 1-37b, ..., 1-336b, x are obtained. Since x indicates dummy data, not encoded data, dummy data is included.

  The operation of the communication system 100 configured as above will be described. FIG. 5 is a flowchart showing the inter-frame interleaving process performed by the transmission apparatus 10. Here, as an example, a process will be described in which one packet is M = 16 frames and the number of inter-frame interleaving frames is N = 3 frames. The encoding unit 32 encodes the transmission data 30 by convolutional encoding, LDPC encoding, or the like (S10). The encoding unit 32 outputs the encoded data to the inter-frame interleave memory unit 38. The inter-frame interleave memory unit 38 stores the encoded data in order (S12). It is determined whether the encoded data is stored for one packet (S14). If not saved (N in S14), the process returns to Step 12.

  When one packet is stored (Y in S14), the interframe interleaving unit 34 performs interframe interleaving from the encoded data of the (MN−2) th frame (S16). Similar processing is repeated to determine whether or not the Nth interleaving has been completed (S18). If the N-th process has not been completed (N in S18), the process returns to step 16. When the N-th process is completed (Y in S18), the inter-frame interleave control unit 36 permits data transmission to the modulation unit 40 (S20). If the processing for one packet has not been completed (N in S22), the process returns to step 16. When the process for one packet is completed (Y in S22), the process is terminated.

  FIG. 6 is a flowchart illustrating the inter-frame deinterleaving process performed by the receiving device 20. Here, a process in which one packet is M = 16 frames and the number of inter-frame interleaved frames N = 3 is described. The demodulator 50 demodulates the received data (S50). The inter-frame deinterleaving unit 52 performs inter-frame deinterleaving processing using the demodulated data (S52). It is determined whether or not N-1 frames have been deinterleaved between frames (S54). If not completed (N in S54), the data of the (MN−2) and (MN−3) frames included therein are stored in the interframe deinterleave memory unit 56 (S56), and the process returns to step 52. .

  If it has been completed (Y in S54), it is determined whether it is within the remaining N-1 frames (S58). If it is not within the remaining N−1 (N in S58), the decoding unit 60 executes a decoding process (S62). On the other hand, if it is within the remaining N−1 (Y in S58), the data of the (MN−2 +) and (MN−3 +) frames are read from the inter-frame deinterleave memory unit 56 (S60). Following this, the decoding unit 60 executes a decoding process (S62). If the inter-frame deinterleaving process for one packet has not been completed (N in S64), the process returns to step 50. If the inter-frame deinterleaving process for one packet has been completed (Y in S64), the process is terminated.

  According to the embodiment of the present invention, blocks are distributed in M frames, so that it is possible to suppress a decrease in frame utilization efficiency even when inter-frame interleaving is executed. Also, in the case of interleaving between 3 frames, the block that did not use 2/3 frame in the second frame from the last and 1/3 frame in the last frame is changed to the 2/3 frame and the second frame of the first frame. Since 1/3 of the frame is stored, dummy data can be prevented from being stored. In addition, since no dummy data is stored, it is possible to suppress a decrease in frame use efficiency. Moreover, since dummy data is not stored, power consumption can be reduced. Further, since the encoded data included in the last two frames is distributed to the first frame and the last frame, the interleaving distance can be increased. Further, since the interleaving distance is increased, the performance can be improved as compared with the normal inter-frame interleaving.

  In the above, this invention was demonstrated based on the Example. This embodiment is an exemplification, and it will be understood by those skilled in the art that various modifications can be made to the combination of each component and each processing process, and such modifications are also within the scope of the present invention. .

  In the embodiment of the present invention, since the communication system 100 is based on a wireless communication system, the transmission device 10 and the reception device 20 are included in the wireless communication device. However, the present invention is not limited to this. For example, the communication system 100 may be based on a wired communication system. At that time, the transmission device 10 and the reception device 20 are included in the wired communication device. According to this modification, the present invention can be applied to various devices.

  In the embodiment of the present invention, inter-frame interleaving is performed twice for N-1 frames according to the number of inter-frame interleaving. However, the present invention is not limited to this. For example, an interframe interleave result once performed may be stored in the interframe interleave memory unit 38 and read from the interframe interleave memory unit 38 when the interframe interleave result is required again. According to this modification, the degree of freedom of configuration can be expanded.

  10 transmitting device, 20 receiving device, 30 transmission data, 32 encoding unit, 34 inter-frame interleaving unit, 36 inter-frame interleaving control unit, 38 inter-frame interleaving memory unit, 40 modulating unit, 50 demodulating unit, 52 inter-frame de-interleaving , 54 inter-frame de-interleave control unit, 56 inter-frame de-interleave memory unit, 60 decoding unit, 62 received data, 70 communication path, 100 communication system.

Claims (5)

An input unit for inputting data for M (M is an integer of 2 or more) frames;
An inter-frame interleaving unit that performs N (N is an integer of 2 or more) inter-frame interleaving with respect to M frames of data input in the input unit;
An output unit for outputting data for M frames interleaved between N frames in the interframe interleaving unit,
The inter-frame interleaving unit generates M × N blocks by dividing the data for M frames input in the input unit into data for each frame and then dividing the data of each frame into N. An interleaving apparatus that distributes N blocks included in one frame into N frames within M frames.   The inter-frame interleaving unit distributes N blocks included in the first frame one by one from the corresponding frame to the frame after (N−1), and also distributes to blocks included in subsequent frames. The interleaving apparatus according to claim 1, wherein the block deviating from the Mth frame is arranged from the head to the (N−1) th frame by repeating. An input unit that inputs data for M (M is an integer of 2 or more) frames and interleaved with N (N is an integer of 2 or more) frames;
An inter-frame deinterleaving unit that performs inter-N frame deinterleaving on M frames of data input in the input unit;
An output unit that outputs data for M frames deinterleaved between N frames in the interframe deinterleave unit,
In the data for M frames input in the input unit, the data for M frames before interleaving between N frames is divided into data for each frame, and then the data of each frame is divided into N, thereby M × N The deinterleaving apparatus is characterized in that N blocks included in one frame are distributed in N frames in the M frame. Inputting data for M (M is an integer of 2 or more) frames;
Performing interleaving N (N is an integer of 2 or more) frames on the input M frames of data;
Outputting data for M frames interleaved between N frames,
The executing step divides the input M frame data into data for each frame, and then divides the data of each frame into N to generate M × N blocks. An interleaving method characterized in that N blocks included in one frame are distributed over N frames. Inputting data for M (M is an integer of 2 or more) frames and interleaved between N (N is an integer of 2 or more) frames;
Performing inter-N frame deinterleaving on the input M frames of data;
Outputting data for M frames deinterleaved between N frames,
In the data for M frames input in the input step, M × M frames are divided into N-frame data after M frames before interleaving between N frames are divided into data for each frame, and M × A deinterleaving method characterized in that N blocks are generated and N blocks included in one frame are distributed in N frames in M frames.

Images