JPH0685513B2 - Data retransmission transmission method - Google Patents

Description

The present invention relates to a data retransmission transmission method applied to, for example, mobile communication with fading, and when received data has an error, block data including the data is retransmitted. It is a thing.

"Conventional technology" As a method for realizing high-quality digital data transmission in mobile communication with fading, there are conventional methods such as time diversity and signal retransmission method (ARQ).

In time diversity, the same data is transmitted a certain number of times from the beginning regardless of errors in the received data. Therefore, in mobile communication in which the average value of the reception level fluctuates greatly, data is wastefully transmitted in places where the average reception level is high and there are few errors, so the transmission efficiency is low and the average reception level is low and errors are low. In many places, the number of transmissions is determined to be a certain number of times, so there is a drawback that insufficient quality can be obtained.

On the other hand, in ARQ, the transmission data is divided into multiple blocks with a length of several hundred bits and transmitted for each block. When an error is detected in the received block data, a retransmission request is issued and the block data Will be retransmitted. In this way, retransmission of the same block data is repeated until no error is detected in the received block data.
Therefore, ARQ has a feature that high quality transmission can be realized because the number of transmissions adaptively changes according to the line quality. However, in normal ARQ, only the block data at the time of reception is used, and the data received up to the previous time is not used, so the number of retransmissions increases and the transmission efficiency drops significantly in places with poor line quality. There was a drawback.

It is an object of the present invention to provide a data retransmission transmission system which eliminates the drawback that the number of retransmissions increases and the transmission efficiency greatly decreases when the line quality is poor.

"Means for Solving Problems" According to the present invention, by utilizing block data received by retransmission and block data received up to the previous time, time diversity is performed for each bit of block data,
The time-diversified data is checked for errors. As described above, in the present invention, since the block data received up to the previous time is effectively used, the number of data errors is reduced, the number of retransmissions is reduced as compared with the conventional ARQ, and high efficiency and high quality data transmission is achieved. Can be realized.

[First Embodiment] FIG. 1 shows a first embodiment of the present invention. Since the data transmitting side may have the same configuration as the conventional ARQ, it is omitted in FIG. 1 and only the receiving side is shown. The demodulated data is output from the receiver 1 to the demodulation output terminal 2, and the reception level for each bit thereof is output to the reception level output terminal 3. The demodulation output terminal 2 is connected to a sign discriminator 4 which makes a binary judgment for each bit (“1” or “0”) and a reception level output terminal 3
Are respectively connected to the AD converters 5, and the judgment binary data from the code judging unit 4 and the reception level converted into the digital signal from the AD converter 5 are temporarily stored in the buffer memory 6. The buffer memory 6 is connected to the arithmetic control unit 7, performs time diversity processing on the block data received up to the previous time and the block data received this time, performs error detection on the processed data, and if there is no error, data The correct block data is output to the output terminal 8, and when an error is detected, the transmitter 9 is requested to retransmit the block data and the received block data up to that point is stored in the memory 10.

First, the first reception processing of block data will be described. The sign of the demodulated signal from the demodulation output terminal 2 of the receiver 1 is judged by the sign judging device 4 as either binary data (0, 1) for each bit, and the detected reception level from the reception level output terminal 3 is detected. Is sampled by the AD converter 5 at regular intervals and converted into a digital signal. The binary data from the code judging unit 4 and the reception level from the AD converter 5 are stored in the buffer memory 6 in correspondence with the bits of the block data.
After the reception of the block data, the arithmetic control unit 7 reads the reproduction block data stored in the buffer memory 6 and performs error detection on this data. If no error is detected, it is regarded as the reception block data and is output as the data output terminal 8 And a reception signal indicating that the transmitter 9 has received the error without error, and waits for the reception of the next block data.

On the other hand, when an error is detected in the reproduction block data, the arithmetic control unit 7 transfers the reproduction block data and the reception level stored in the buffer memory 6 to the memory 10 and transmits the retransmission request signal from the transmitter 9. To do. Upon receiving this retransmission request signal, the transmitting side retransmits the block data. The reception signal of this data retransmission is processed in the same manner as the first reception processing, and the reproduction block data and reception level thereof are stored in the buffer memory 6. Arithmetic control unit 7
Reads the previous playback block data and the reception level from the memory 10 and the current playback block data and the reception level from the buffer memory 6 in correspondence with the bit of the block data, respectively, compares the reception levels of the two,
Time diversity processing is performed to rewrite the data and reception level of the corresponding bit in the data with the higher reception data and reception level. After the end of the time diversity processing, the arithmetic control unit 7 reads the block data after the time diversity processing stored in the memory 10 and detects an error. If no error is detected, it is output to the data output terminal 8 as reception block data. At the same time, a reception signal indicating that the data has been received without error from the transmitter 9 is transmitted, and the reception of the next block data is awaited.

On the other hand, when an error is detected, the arithmetic control unit 7 transmits a retransmission request signal from the transmitter 9 and repeats the re-transmission / reception processing until no error is detected in the reproduction block data after the time diversity processing.

In places where the line quality is poor, the number of retransmissions becomes so large that the transmission efficiency decreases, so that the number of retransmissions can be limited in order to improve the transmission efficiency.

[Second Embodiment] FIG. 2 shows a second embodiment of the present invention in which parts corresponding to those in FIG. In this example, the demodulated signal from the demodulation output terminal 2 is supplied to the A / D converter 11, and this converted digital signal is stored in the buffer memory 6.

First, the first reception processing of block data will be described. The demodulated signal from the receiver 1 is sampled by the A / D converter 11 corresponding to the bits of the received block data, converted into a digital signal, and stored in the buffer memory 6. N-bit block data (x ₁₁ x ₁₂ ... x _1N ) stored in the buffer memory 6 And After receiving the block data, the arithmetic control unit 7 stores the demodulated signal stored in the buffer memory 6. Read the received block data by judging any of binary data (0, 1) for each bit, perform error detection on this reproduced block data, and if no error is detected, receive it The data is output to the data output terminal 8 and a reception signal indicating that the data has been received without error is transmitted from the transmitter 9 to wait for reception of the next block data.

On the other hand, when an error is detected, the arithmetic control unit 7 outputs the demodulated signal stored in the buffer memory 6. Is transferred to the memory 10 and a retransmission request signal is transmitted from the transmitter 9. Here, the vector stored in the memory 10 is And At this time Becomes Of the demodulated signal when received by resending Is stored in the buffer memory 6 as in the previous block data receiving process. The arithmetic and control unit 7 uses the memory 10 Of the demodulated signal of this time from the buffer memory 6 Are read according to the bit data of each block, and the time diversity processing is performed to add and To get Memory 10 Rewrite Memory after time diversity processing
Remembered in 10 Is determined to be any of binary data, the received block data is reproduced, error detection is performed on the reproduced block data, and if no error is detected, it is output to the data output terminal 8 as the received block data, and Transmitter 9
Sending a receipt signal indicating that it was received with more error,
Wait for the next block data to be received.

On the other hand, when an error is detected, the arithmetic control unit 7 transmits a retransmission request signal from the transmitter 9 and repeats the re-transmission / reception processing until no error is detected in the reproduction block data after the time diversity processing. the sample vector from the kth reception Then, the content of the inner diameter of the memory 10 is Becomes As the number of receptions increases, Like the normal ARQ because it increases the reliability of The number of retransmissions can be reduced as compared with the method of reproducing the block data by using only, and the transmission efficiency is improved.

In places where the line quality is poor, the number of retransmissions becomes so large that the transmission efficiency decreases, so that the number of retransmissions can be limited in order to improve the transmission efficiency.

"Third Embodiment" FIG. 3 shows the third embodiment of the present invention with the same reference numerals when corresponding to FIGS. In this example, the demodulated signal at the demodulation output terminal 2 is converted into a digital signal as in the second embodiment, and the reception level at the reception level output terminal 3 is set to the first level.
Similar to the embodiment, it is converted into a digital signal, and the digital signal is multiplied bit by bit by the multiplier 12 and stored in the buffer memory 6.

First, the first reception processing of block data will be described. The demodulated signal and reception level of the receiver 1 are A /
The D block converters 11 and 5 sample the received block data bit by bit and convert into digital signals. Both digital signals are multiplied by the bit converter by the multiplier 12 and stored in the buffer memory 6. Here, the sample vector of the demodulated signal of the block data of N bits is The sample vector of the reception level Then, in the buffer memory 6, Is memorized. After receiving the block data, the arithmetic control unit 7 causes the buffer memory 6 to execute the multiplication result. Is read, and the sign of one of binary data (0, 1) is determined for each bit to reproduce the received block data,
Error detection is performed on the reproduction block data, and if no error is detected, the reproduction block data is output to the data output terminal 8 as reception block data, and a reception signal indicating that the transmitter 9 has received the error is transmitted. Then, the reception of the next block data is awaited.

On the other hand, when an error is detected, the arithmetic control unit 7 compares the demodulated signal stored in the buffer memory 6 with the reception level. Is transferred to the memory 10 and a retransmission request signal is transmitted from the transmitter 9. Here, the vector stored in the memory 10 is And At this time Becomes Each demodulated signal and each sample vector of the reception level when received by retransmission are multiplied by the multiplier 12 bit by bit as in the first block data reception process, and then stored in the buffer memory 6. At this time, the buffer memory 6 Is memorized. The arithmetic and control unit 7 uses the memory 10 Of the current demodulated signal and the reception level from the buffer memory 6. Are read according to the bit data of each block, and the time diversity processing is performed to add and To get After this memory 10 Rewrite After the time diversity process is completed, the arithmetic unit 7 is stored in the memory 10. Is judged as something of binary data, the received block data is reproduced, error detection is performed on the reproduced block data, and if no error is detected, it is treated as received block data and is output to the data output terminal 8. While outputting
A reception signal indicating that the data has been received without error is transmitted from the transmitter 9, and the reception of the next block data is awaited.

On the other hand, when an error is detected, the arithmetic control unit 7 transmits a retransmission request signal from the transmitter 9 and repeats until no error is detected in the block data after time diversity. of the demodulated signal by the kth reception And of the reception level Then, the contents of memory 10 Becomes As the number of receptions increases, Like the normal ARQ because it increases the reliability of The number of retransmissions can be reduced as compared with the method of reproducing the block data by using only, and the transmission efficiency is improved.

In places where the line quality is poor, the number of retransmissions becomes so large that the transmission efficiency decreases, so that the number of retransmissions can be limited in order to improve the transmission efficiency.

In each of the above embodiments, the case where the error detection code is used to detect an error in the reproduced block data has been described. However, an error correction code that can be error-corrected is used, and the operation control unit 7 performs the error correction process. At the same time, when there is an error that exceeds the correction capability, the retransmission request may be made by detecting this error. Further, although the length of the block data has been described as a constant value, the block data length may be variable so as to maximize the transmission efficiency according to the state of the transmission path.

[Advantages of the Invention] As described above, the present invention performs time diversity processing using retransmitted block data, and therefore has the advantage of being able to improve transmission efficiency over conventional ARQ. Further, from a different point of view, the present invention can be regarded as time diversity in which the number of branches can be adaptively changed according to the line quality, so that it is possible to realize higher quality data transmission than the conventional time diversity. There are advantages.

[Brief description of drawings]

FIG. 1, FIG. 2 and FIG. 3 are block diagrams showing the receiving side in one embodiment of the present invention.

Claims (7)

[Claims] 1. A data retransmission transmission method, wherein a retransmission request is made when an error is detected in received block data, in each bit between the block data received by retransmission and the block data received up to the previous time. A data retransmission transmission method, characterized in that time diversity processing is performed for each block, and error detection is performed on the block data subjected to the time diversity processing. 2. The time diversity processing compares the received data of the block data received up to the previous time with the received level of the block data when received by the retransmission request in correspondence with the bit of the block data, and up to the previous time. It is a process of rewriting the data and the reception level for each bit of the received block data to the data and the reception level of the larger reception level, and performing the error correction or the error detection on the rewritten data. The data retransmission transmission method according to claim (1). 3. When an error is detected, the retransmission request is made and the rewritten data and the reception level are used as reception block data until the retransmission block data based on the retransmission request is received. A data retransmission transmission method according to claim (2). 4. The time diversity processing uses a sample value of a receiver demodulation output for each bit of block data received by retransmission as a sample vector, and this and the receiver demodulation output for the block data received up to the previous time. This is a process of adding a vector of sample values to each bit of the block data, and for each bit of the vector that has been subjected to the addition process, the sign of any one of the binary data is determined, and the error is detected in the block data of the result. The data retransmission transmission method according to claim (1), wherein correction or error detection is performed. 5. When an error is detected, a receiver demodulation output for the received block data until the retransmission request is made and the addition-processed vector is received until retransmission block data based on the retransmission request is received. And a vector of sample values of
The data retransmission transmission method described in the item. 6. The time diversity processing uses a vector as a product of a sampled value of a receiver demodulation output and a reception level for each bit of block data received by retransmission, and obtains a vector of this product and the block data received up to the previous time. This is a process of adding a vector of a product of a reception level for each bit and a sample value of a receiver demodulation output in correspondence with each bit of block data, and determining the sign of any of binary data for each bit of the processed vector. The data retransmission transmission method according to claim (1), characterized in that the error correction or error detection is performed on the resulting block data. 7. When an error is detected, a receiver demodulation output for the received block data until the retransmission request is made and the addition-processed vector is received until the retransmission block data based on the retransmission request is received. The data retransmission transmission method according to claim (6), characterized in that the vector is a product of the sampled value and the reception level.