JP2999110B2 - Wireless communication method and wireless communication device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates relates to a wireless communication method and a radio communication apparatus that have use <br/> interleaving scheme. 2. Description of the Related Art In recent years, an interleave method has been used as a method corresponding to a burst error in communication for transmitting and receiving information between apparatuses. In particular, in wireless communication using radio waves, light, or the like between transmission / reception devices, the use of a code having an error correction capability can prevent an error from occurring for a burst error. Also,
The interleave method is also used in wireless communication between a computer main body and an input / output device (keyboard or the like) that wirelessly communicates with the computer.

However, if the size of the matrix for interleaving is large, there is a capability of coping with errors, but if the amount of data to be transmitted is small, the transfer efficiency is reduced. Therefore, a method of changing the size of interleaving on the transmitting side has been adopted. ing. However, when the interleave size is changed, transfer efficiency is deteriorated in transmitting information notifying that the interleave size has changed, and an improvement thereof is desired.

[0003]

2. Description of the Related Art FIG. 5 is an explanatory diagram of a conventional interleave system, and FIG. 6 is a configuration diagram of a conventional example. The interleaving method is shown in FIG. In the following description, a ₀₀ , a ₀₁ , a ₀₂ ... A _0N , a ₁₀ , a
₁₁ · · a _1N, the _{··· a M0, a M1 ·· a} MN when transmitting from the transmission side, stored in N rows M rows of the matrix N × M (= Ix), by interchanging the original order, The data is read out sequentially in the vertical direction and transmitted. The order of the transmission data in this case is as follows.

[0004] a₀₀, A_Ten, ... a_M0, A₀₁, A₁₁..A
_M1, ..., a_0N..A_MN It should be noted that such data is subject to error detection and correction during transmission.
Redundant bits are included in the encoding for
Burst error (continuous
Occurs, for example, a₀₀, A_Ten, ... a
_M0Even if an error occurs in the data of
Data (for example, a₀₀, A₀₁, A₀₂..A _0N1) in
Since this is a bit error, it must be detected and corrected.
Can be. In this conventional example, the transmitting side (not shown)
Are encoded by a convolutional encoder, and the decoding
A commonly used Viterbi decoder shall be used.
You.

[0005] A conventional communication system using the interleave system can cope with continuous errors. However, if the continuous errors are lengthened, the interleave matrix size also becomes large. in this case,
The minimum amount of data to be sent collectively increases, and even when it is desired to send a small number of bits, it is necessary to send data of a matrix size, and the transfer efficiency is deteriorated. However, if the error cannot be corrected, matrix-size data is discarded, and the transfer efficiency deteriorates. For this reason, it is desirable that the interleave size be variable to some extent.

Therefore, on the transmitting side, when the amount of data to be transmitted is long, the interleave matrix size (N × M
= Ix) is increased, and when it is short, the matrix size is reduced from the transmission efficiency.

The frame configuration in that case is shown in FIG. At the beginning of each frame (a unit of data) on the transmitting side. , Interleaved information (Ix) is added, followed by interleaved data. It is to be noted that a data size corresponding to a plurality of matrix sizes can be stored in one frame.

FIG. 6 shows A.I. of FIG. Is shown, the interleave information at the head of the frame is separated by an interleave information separation unit 61, and M × N
Is supplied to the address control unit 63. The received data part is FIFO (First In First Out) 6
0 is input in series to adjust the timing, output after a fixed time, and sequentially stored in an SRAM (Static RAM) 62.

The address control section 63 uses the received interleave information to convert the received data into the data shown in FIG. The SRAM 62 is read out so as to become the time-series data in the row direction shown in FIG. The read time-series data is decoded by the Viterbi decoder 64. The Viterbi decoder 64 decodes the convolutionally encoded data, and at the same time, performs error detection and correction (when the number of bits is equal to or less than a certain number of bits) to generate a decoded output.

[0010]

In the above-described conventional matrix-variable interleaving communication system including an error correction function, it is necessary to add interleaving information to each frame. In particular, when the data amount is short, the interleaving information is required. However, there is a problem that transmission efficiency is deteriorated by transmitting the data.

[0011] Further, although the confidentiality of communication contents can be maintained by interleaving, in the case of a system in which interleaving information is added to each frame, there is a problem that confidentiality cannot be maintained by intercepting the interleaving information. Was.

[0012] The present invention is to provide a radio communication method and a radio communication device decoding corresponding to the interleave size Ru can have changed on the reception side without sending interleaved information to the receiving side even if the interleave size variable at the transmission side With the goal.

[0013]

FIG. 1 is a block diagram showing the principle of the present invention. In FIG. 1, reference numeral 1 denotes an automatic discrimination unit for judging a current interleave size based on received data, 2 denotes a memory, 3 denotes an address control unit, 4 denotes a Hamming distance calculation unit for each size, 5 denotes an interleave size judgment unit, and 6 denotes It is a decoding unit.

According to the present invention, a received frame is decoded using a plurality of types of interleave sizes to detect respective hamming distances, determine an interleave size when the hamming distance is shortest, and determine a frame based on the interleave size. Is performed.

[0015]

The data on which error correction coding has been performed on the transmission side is interleaved in a plurality of types (N × M = Ix, I
When the interleaved data is transmitted using one of the data, the data is received by the receiving side shown in FIG. The received data is input to the decoding unit 6, stored in the memory 6a, and stored in the memory 2 of the automatic discrimination unit 1.

When the received data for one frame is received, the Hamming distance calculating unit 4 for each size of the automatic discrimination unit 1
Of each interleave size (I0, I1
... In) memory 2 by the address control unit 3
The data received from is read out, and the Hamming distance is calculated for each size.

The size-specific Hamming distance calculator 4 performs decoding including error correction on the data read from the memory 2 according to the specified interleave size, and compares the decoded data with the read data. And calculate the number of different bits for each bit. The number of bits indicates the Hamming distance, and the calculation result for each interleave is output to the interleave size determination unit 5.

When the calculation of the Hamming distance for each of a plurality of types of interleave sizes I0 to In prepared in advance is completed, the interleave size determination unit 5 calculates the Hamming distance with the smallest Hamming distance from the calculation result of the Hamming distance for each interleave size. A certain interleave size is determined, and the result of the determination is output to the decoding unit 6. This determination result occurs before the reception of one frame is completed.

When the interleaving size is notified from the automatic discriminating unit 1 before the received data is stored in the memory 6a for one frame, the decoding unit 6 reads out from the memory 6a by address control based on the size and decodes the data. I do.

[0020]

FIG. 2 is a block diagram of the embodiment, FIG. 3 is an operation timing of each section of the embodiment, and FIG. 4 is a configuration example of a Hamming distance calculation section.

In FIG. 2, reference numerals 20 and 21 denote FIFOs 1 and 2 for adjusting timing with a communication path, and FIFOs 2 and 22 for adjusting timing with a decoder. SRAMs 1 and 23 decompress interleaved data. Is a known Viterbi decoder that performs decoding in accordance with the above, an address control unit that generates a read address corresponding to an interleave size specified to restore interleaved data, and 25 is an interleave size automatic determination unit ( 1 corresponds to the automatic discrimination unit 1 in FIG.
(Corresponding to the memory 2 in FIG. 1), 27 is an address controller (corresponding to 3 in FIG. 1) for generating a read address of the SRAM 2 corresponding to each interleave size, and 28 is a hamming distance calculator (corresponding to 4 in FIG. 1). ) And 29 are interleave size determination units.

In FIG. 3 to, as shown in FIG.
O1, FIFO2,... The timing of each unit of the Hamming distance calculation / judgment unit is shown on the same time axis.
Shows the operation timing of the SRAM 2 and the hamming distance calculation unit by enlarging the time of one frame (the reception time of the frame B).

The operation of FIG. 2 will be described with reference to the operation timing of each section shown in FIG. In advance, (n + 1) I0, I1, I2,... In can be used as an interleave size between the transmitting side and the receiving side apparatus shown in FIG. 2, and one of them is selected and used. It has been decided to do so.

As shown in FIG. 3, variable interleave size data encoded by a convolutional code is transmitted from the transmitting side in a frame configuration. Hereinafter, each frame is referred to as a frame A, a frame B, a frame C,.

If the minimum data amount of a block constituting a frame is Fs, the size I of each interleave is
The smallest size among 0 to In is Fs / (n + 1)
Do the following. As a result, the automatic determination of the interleave size, which will be described later, can be performed within one block (one frame is composed of a plurality of blocks) in one frame.

The frame data is stored in a FIFO
When one frame A is received and one frame A is received, it is written at high speed to the FIFO 2 (21) at the beginning of the next frame B as shown by the symbol "W" in FIG. However, as shown by the symbol "W", the data is also written to the SRAM 2 (26) of the interleave size automatic determination unit 25.

When writing to the SRAM 2 for one frame (the maximum size that can be taken) is performed, the address control unit 27 follows the initial interleave size I0 as shown in an enlarged manner in FIG. A read address is generated, and a certain number of bits are read. The read data is input to the Hamming distance calculation unit 28 as shown by in FIG. 3, where the data is decoded and the Hamming distance is calculated.

When the hamming distance H0, which is the result of calculation at the interleave size I0, occurs, it is output to the interleave size determination unit 29. Thereafter, reading from the SRAM 2 and calculation of the Hamming distance are similarly performed for the interleave size I1, and the resulting Hamming distance H1 is output. Hereinafter, reading and calculation of the hamming distance are sequentially performed for each interleave size I2... In, and the hamming distance H2.
Hn is output.

FIG. 4 shows an example of the configuration of the hamming distance calculator 28 described above. The hamming distance calculator 28 includes a controller 282
, Each interleave size is generated in order, and the SRAM 2 (FIG. 2) corresponds to the generated interleave size.
One of the data read from is input to the delay circuit 280 and the other is input to the Viterbi decoder 281 for decoding. The serial data from the Viterbi decoder 281 is input to the comparison and counting unit 283 in synchronization with the output from the delay circuit 280. The comparison and counting unit 283 compares two inputs in a bit-by-bit manner and counts when a mismatch bit is detected. This counting result indicates the Hamming distance.

If the transmitting side sets the interleave size to I
If the transmission is set to 0, the read data and the decoding result all match, and the hamming distance becomes 0.
If it is not I0, the Hamming distance increases as the amount of data to be processed increases. Similarly, calculation is performed from I1 to In.

Returning to FIG. 2 and FIG. 3, when the calculation results of the Hamming distances corresponding to all the interleave sizes I0 to In are obtained, the interleave size determination unit 29 determines the smallest Hamming distance among them. Is determined, and the result of the determination is output to the address control unit 24. The hamming distance calculation and determination operation ends before the end of frame B as shown in FIGS.

The result of this determination specifies the interleave size for frame A.
4 uses the specified interleave size and
The data of frame A stored in M1 is read.
The read data is decoded and error-corrected by a Viterbi decoder 23 that decodes the convolutional code, and generates a decoded output.

As can be seen from FIGS. 3A and 3B, when the Hamming distance calculation and the determination operation are performed for the frame A, the frame B is received, but the data is stored in the FIFO 1 which is already empty. . The decoding of the data of the frame A stored in the SRAM1 is performed when the frame C is received. Since the frame B stored in the FIFO1 is written into the SRAM1 at the beginning of the decoding, the frame C is stored in the FIFO1. be able to. Then, when the frame C is received, the Hamming distance calculation for the frame B is executed.

As described above, the three operations of storing the frame data, determining the interleave, and decoding based on the determination result are sequentially executed for all the frames while shifting sequentially.

[0035]

According to the present invention, the transmission efficiency can be improved because the size of the interleaving rows and columns is made variable and the receiving side is not notified of the size, and the confidentiality of the communication contents and the noise immunity due to the interleaving are improved. Performance can be improved.

Further, by automatically discriminating the interleave information on the receiving side, it is possible to obtain an effect that a fixed password is not required and eavesdropping becomes difficult.

[Brief description of the drawings]

FIG. 1 is a principle configuration diagram of the present invention.

FIG. 2 is a configuration diagram of an embodiment.

FIG. 3 is a diagram illustrating operation timing of each unit of the embodiment.

FIG. 4 is a configuration example of a Hamming distance calculation unit.

FIG. 5 is an explanatory diagram of a conventional interleaving method.

FIG. 6 is a configuration diagram of a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Automatic determination part 2 Memory 3 Address control part 4 Hamming distance calculation part according to size 5 Interleave size determination part 6 Decoding part 6a Memory

Claims (3)

(57) [Claims] 1. A radio communication direction using the interleaving scheme
In the method , the transmitting side sequentially transmits frames obtained by encoding data interleaved with any one selected from a plurality of types of interleaving sizes for each frame, and the receiving side receiving the frames includes: of
Data is stored in a memory, frame data is read out from the memory in order for each of the plurality of types of interleave sizes and decoded, a Hamming distance for each interleave size is calculated, and interleaving of a received frame is performed from each calculation result. Data received by judging the size and determining the interleave size
A wireless communication method using an interleave scheme, wherein decoding is performed by returning to the original data . 2. The method of claim 1, the memory for storing data received frame, according to the order that is set from among previously prepared plurality of types of interleaving size, the original data corresponding to each interleave size radio communication method of using an interleaving scheme, wherein Rukoto the read address calling eggplant back to. 3. A wireless communication device using an interleave method.
In the system, the transmitting side uses multiple types of interleave sizes for each frame.
Interleaved data with any one selected from
The receiver that transmits the encoded frame and receives the frame is interleaved.
An automatic discriminating unit for discriminating noise, and a discrimination result of the automatic discriminating unit.
Restores the received frame to the original data and decodes it.
A first decoding unit for storing the data of the received frame.
That the memory, and the second decoding unit intends row decoding for data read from said memory for each interleave size, the previous SL decoded data by the second decoder and reading data from the memory A size-based hamming distance calculator for comparing the number of mismatched bits, and an interleave for determining the interleave size of each received frame based on the hamming distance for each interleave size generated from the size-based hamming distance calculator. A wireless communication device using an interleave method, comprising a size determination unit.