JP4255978B2 - Transmitter and transmission method thereof - Google Patents

Description

  The present invention relates to an interleaver and deinterleaver applicable to a communication system employing error correction coding, and in particular, an interleaver, a deinterleaver that rearranges data over a plurality of communication paths, and The present invention relates to a communication device provided.

  Hereinafter, a communication device in a conventional communication system will be described. For example, in a communication system using interleaving such as wireless LAN 802.11 and HISWAN, bit interleaving is performed on data after error correction coding in order to cope with burst errors caused by fading and the like. Specifically, the order of the data after error correction coding is changed at a period longer than the fading period by the interleaver on the transmission side, and the order is restored to the original order by the deinterleaver on the reception side, and then decoding is performed. Thereby, burst errors are randomized and data errors are reduced.

  Here, a conventional communication system defined by wireless LAN 802.11a (see Non-Patent Document 1), which is a US standard, will be described. First, in the communication device on the transmission side, error correction coding is performed on the information data, and further, the order of the data after error correction coding is rearranged (conventional interleaving method), and further after the rearrangement Data is modulated by a predetermined modulation method and transmitted. Then, the communication device on the receiving side demodulates the received data, restores the demodulated data to the original order, and then decodes it.

IEEE Std. 802.11a-1999

  The communication apparatus in the conventional communication system has the following problems.

  FIG. 6 is a diagram showing an interleaving method in the conventional communication system. Specifically, FIG. 6A shows a binary phase shift keying (BPSK) interleaver, and rearrangement is performed by writing in the horizontal direction and reading in the vertical direction. FIG. 6B shows a QPSK (Quadrature Phase Shift Keying) interleaver, which, like BPSK, writes in the horizontal direction and reads in the vertical direction. Note that the size and shape of the interleaver are specialized for each modulation method, and the interleaving process is closed for each communication path.

  However, in communication using a plurality of communication paths, when an interleaver that is closed for each communication path is used as in the above-described conventional communication system, for example, there is a communication path in which the communication status is significantly deteriorated in the use communication path In some cases (such as when suddenly large interference is applied to one of the communication paths), there is a problem that the throughput is significantly reduced.

  The present invention has been made in view of the above, and is capable of rearranging data of a plurality of communication paths collectively, that is, an interface capable of maintaining high throughput by averaging the communication status of each communication path. It is an object of the present invention to obtain a Lleaver, a corresponding deinterleaver, and a communication device including these.

  In order to solve the above-described problems and achieve the object, the interleaver according to the present invention includes an interleaver provided in a communication device that performs communication using N (an integer of 2 or more) communication paths. A plurality of inter-communication channel interleaving means for rearranging a data sequence for transmission to the N communication channels in two dimensions in a time direction and a frequency-divided communication channel direction is provided. .

  According to the present invention, for example, the data series of one error correction encoding unit output is distributed and transmitted to a plurality of frequency-divided communication paths. As a result, even if a specific communication channel suddenly receives the influence of large interference and cannot communicate independently, errors are dispersed by interleaving between multiple communication channels, so error correction is possible. Become.

  According to the present invention, the data series to be transmitted is distributed and transmitted to a plurality of frequency-divided communication paths. As a result, even when a specific communication channel is affected by large interference and communication cannot be performed independently, errors are dispersed by interleaving and deinterleaving between multiple communication channels, so error correction is possible. It becomes possible, and there is an effect that a decrease in throughput can be avoided.

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

Embodiment 1 FIG.
FIG. 1 is a diagram showing a configuration of a communication device using an interleaver and a deinterleaver according to the present invention. Specifically, FIG. 1A shows the configuration of a communication device on the transmission side, and FIG. This shows the configuration of the communication device on the side.

  The communication apparatus according to the present embodiment is premised on performing communication using a plurality of communication paths divided by frequency, and here, N communication paths are used. 1A includes an M number of error correction encoding units 1-1 to 1-M, an interleaver 2 that rearranges data between a plurality of communication paths, and N number of modulation units 3-1 to 3-1. 3-N provided. 1B includes an N number of demodulating units 4-1 to 4-N, a deinterleaver 5 that rearranges data among a plurality of communication paths, and an M number of error correction decoding units 6-. 1-6-M.

  The M error correction encoding units 1-1 to 1-M execute a predetermined encoding process on data to be transmitted (transmission data). The interleaver 2 performs rearrangement processing (interleaving between a plurality of error correction encoded outputs) for each communication path using all of the M error correction encoded outputs. The N modulation units 3-1 to 3-N modulate and output the rearranged transmission data assigned to each communication path by a predetermined modulation method. On the other hand, in the communication device on the reception side, N demodulation units 4-1 to 4-N demodulate the reception signal for each communication path. The deinterleaver 5 rearranges the data rearranged by the interleaver 2 in the original order (returns the data order). The error correction decoding units 6-1 to 6-M decode the original transmission data by a decoding method corresponding to the error correction encoding units 1-1 to 1-M.

  FIG. 2 is a diagram illustrating a configuration of the interleaver and the deinterleaver according to the present embodiment. The interleaver according to the present embodiment includes a distribution unit 11 and N interleavers 12-1 to 12-N. Further, the deinterleaver according to the present embodiment includes N deinterleavers 13-1 to 13 -N and a distribution unit 14.

  The distribution unit 11 distributes M error correction encoded outputs to N interleavers 12-1 to 12-N. At this time, the distribution unit 11 randomly distributes M error correction encoded outputs to one interleaver. Further, the N deinterleavers 13-1 to 13-N perform a reverse rearrangement to the N interleavers 12-1 to 12-N, and return the data to the original order. The distribution unit 14 distributes the N deinterleaver outputs to the M error correction decoding units 6-1 to 6-M in the reverse operation to the distribution unit 11.

  FIG. 3 is a diagram illustrating an example of the rearrangement method according to the present embodiment. Specifically, FIG. 3 is a diagram illustrating a writing process to each interleaver when (a) is M = 2 and N = 2. (B) is a figure which shows each interleaver output.

  The first communication path corresponding to the interleaver 12-1 uses BPSK as the modulation scheme, the second communication path corresponding to the interleaver 12-2 uses QPSK as the modulation scheme, and each interleaver Assume that the LAN standard 802.11a interleaver is used. That is, the interleaver 12-1 uses FIG. 6A, and the interleaver 12-2 uses FIG. 6B. However, here, as an example, a case where a wireless LAN 802.11a interleaver is used will be described. However, the present invention is not limited to this, and an interleaver used in another standard or system may be used. A Lever may be used. In addition, here, the case of M = 2 and N = 2 is described as an example, but not limited thereto, M may be 1 or more, N may be 2 or more, and if this condition is satisfied, M = N, M <N, or M> N may be used. Furthermore, the modulation method used in each communication channel is not limited to BPSK and QPSK, and other modulation methods such as multi-level modulation may be used.

  In FIG. 3A, the numbers not shaded represent the output of the error correction coding unit 1-1, and the numbers shaded represent the output of the error correction coding unit 1-2. In this example, the number of symbols transmitted on the first communication path and the second communication path is the same. Since QPSK can transmit twice as much data as BPSK, the output of the error correction encoding unit 1-2 is twice the output of the error correction encoding unit 1-1.

  In the distribution unit 11 in FIG. 3A, the output of the error correction encoding unit 1-1 and the output of the error correction encoding unit 1-2 are alternately written in order from the row corresponding to the write number (1-9). . As a result, 1/3 of the output of each error correction coding unit is written into the interleaver 12-1, and the remaining 2/3 is written into the interleaver 12-2. Therefore, since the outputs from the interleavers 12-1 and 12-2 are sequentially read for each column, as shown in FIG. 3B, the error correction encoding unit 1-1 and the error correction encoding unit 1- The two outputs are rearranged and output in a mixed state.

  FIG. 4 is a diagram showing an example of the rearrangement method of the present embodiment other than the above, and in detail, writing to each interleaver when (a) is set to M = 2 and N = 2. It is a figure which shows a process, (b) is a figure which shows each interleaver output. The conditions for the rearrangement method are the same as those in FIG.

  In the distribution unit 11 in FIG. 4A, the output of the error correction encoding unit 1-1 and the output of the error correction encoding unit 1-2 are alternately placed in the write number 1 row of the interleaver 12-1. Then, two are written alternately in the row of write number 1 of the interleaver 12-2. Then, this process is repeated until the process for the line with write number 3 is completed for the interleaver 12-1 and until the process for the line with write number 6 is completed for the interleaver 12-2. To do. Thus, the outputs of the error correction encoding unit 1-1 and the error correction encoding unit 1-2 are rearranged and output by a process different from that in FIG.

  In the present embodiment, the case where the number of transmission symbols is the same in the first communication path and the second communication path has been described as an example, but may not be equal. Further, the distribution to each interleaver may not be uniform. Further, as the sorting method, any method other than the above rearrangement method may be used as long as the output from each error correction coding unit is written to each interleaver so as to be appropriately mixed.

  As described above, in the present embodiment, the output of one error correction coding unit is distributed and transmitted to a plurality of frequency-divided communication paths. As a result, even when a specific communication path is affected by large interference and communication cannot be performed independently, errors are distributed by interleaving and deinterleaving between multiple communication paths. Error correction by the decoding unit is possible, and a decrease in throughput can be avoided. In addition, since the interleaver 2 includes the distribution unit 11 and the interleavers 12-1 to 12-N, the interleaver 2 can cope with an interleaver specialized for a conventional modulation method.

  In the above description, communication using a plurality of frequency-divided communication paths has been described. However, the communication apparatus according to the present embodiment is not limited to this, and as illustrated in FIG. It is also possible to assume communication using a channel (equivalent to a MIMO (Multiple-Input Multiple-Output) communication channel 7-1, 7-2,..., 7-N). For example, FIG. 5 is a diagram illustrating a configuration of a communication system when the communication apparatus illustrated in FIG. 1 uses a MIMO communication path. As described above, by using the rearrangement method of the present embodiment, the same effect as described above can be obtained even when a MIMO communication path is assumed. However, the assumed MIMO communication channel may be realized by a plurality of antennas or may be realized by beam forming as long as it is a MIMO communication channel that realizes a plurality of communication channels by space division. .

  Further, in the present embodiment, even when communication using both a plurality of frequency-divided communication paths and a plurality of space-divided communication paths (MIMO communication paths) is assumed, the same as above An effect can be obtained.

  As described above, the communication method and communication apparatus according to the present invention are useful for communication systems that employ error correction coding.

It is a figure which shows the structure of the communication apparatus using the interleaver concerning this invention. It is a figure which shows the structure of an interleaver and a deinterleaver. It is a figure which shows an example of the rearrangement method. It is a figure which shows an example of the rearrangement method. It is a figure which shows the structure of a communication system when the communication apparatus shown in FIG. 1 uses a MIMO communication path. It is a figure which shows the interleaving method in the conventional communication system.

Explanation of symbols

1-1, 1-2, 1-M error correction coding unit 2 interleaver 3-1, 3-2, 3-N modulation unit 4-1, 4-2, 4-N demodulation unit 5 deinterleaver 6 -1,6-2,6-M error correction decoding unit 7-1,7-2,7-N MIMO communication path 11 distribution unit 12-1,12-2,12-N interleaver 13-1,13- 2,13-N deinterleaver 14 distribution part

Claims (3)

  A plurality of error correction coding means for inputting a plurality of data series and performing error correction coding processing;
  A plurality of time interleaving means provided corresponding to the output sides of the plurality of error correction coding means, respectively, for rearranging the data series output from the error correction coding means in the time direction;
  A plurality of modulators respectively provided corresponding to the output sides of the plurality of time interleaving means, for modulating the data series output from the time interleaving means;
With
  The data series output from each of the plurality of modulators is transmitted to the receiver side through a plurality of communication paths,
  The plurality of time interleaving means rearranges the data series in the time direction using a data size determined in advance according to a modulation scheme of the plurality of modulators provided in correspondence with each other.
A transmitter characterized by that.   Data sequences output from the plurality of modulators are transmitted to the receiver side through a plurality of communication channels having different frequencies or a plurality of communication channels having different modulation schemes.
The transmitter according to claim 1.   An error correction coding step for performing error correction coding processing by a plurality of error correction coding means to which a plurality of data series are respectively input;
  A time interleaving step of rearranging a plurality of data sequences obtained in the error correction coding step in a time direction by a plurality of time interleaving means provided corresponding to the output sides of the plurality of error correction coding means, ,
  A modulation step of modulating a plurality of data sequences obtained in the time interleaving step with a plurality of modulators provided corresponding to the output sides of the plurality of time interleaving means,
  Transmitting a plurality of data series obtained in the modulation step to a receiver side through a plurality of communication paths;
Have
  In the time interleaving step, the plurality of data sequences are converted into the plurality of time interleaves with a predetermined data size in accordance with modulation schemes of a plurality of modulators provided corresponding to the plurality of time interleaving means, respectively. Sort in time direction by means
A transmission method of a transmitter.

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