WO2005008948A1

WO2005008948A1 - Data communication device and data communication method

Info

Publication number: WO2005008948A1
Application number: PCT/JP2004/010675
Authority: WO
Inventors: Takashi Kitahara; Atsushi Sumasu
Original assignee: Matsushita Electric Industrial Co., Ltd.
Priority date: 2003-07-23
Filing date: 2004-07-21
Publication date: 2005-01-27

Abstract

There is provided a data communication device suppressing increase of a buffer capacity of a communication partner device and increase of the scale of the communication partner device. The data communication device includes a transmission processing section (120) for performing initial transmission of packet data to a communication terminal device (150) and re-transmitting the packet data when an error is detected in the packet data by the communication terminal device (150). A re-transmission count distribution calculation section (134) calculates the distribution of the count of the re-transmissions of the packet data performed by the transmission processing section (120). According to the re-transmission count distribution calculated, a continuous transmission count decision section (136) decides the number of times packet data is continuously transmitted in the initial transmission.

Description

Description Data communication device and data communication method

The present invention relates to a data communication device and a data communication method used in a wireless communication system to which a hybrid ARQ (Hibrid-Automatic Repeat reQuest) method is applied. Background art

Conventionally, an ARQ control method applied to a wireless communication system in which data communication is performed between a transmitting and receiving device includes a method called an SR (Selective Repeat) method, and a connection between FEC (Forward Error Correction) and ARQ. There is a so-called combined ARQ scheme (see, for example, “Wave Summit Lectures on Mobile Communication”, 1st edition, pages 239-241, Ohmsha). Hereinafter, an operation in a wireless communication system to which the conventional hybrid ARQ scheme is applied will be described with reference to the drawings.

FIG. 1 is a block diagram illustrating an example of a configuration of a conventional wireless communication system. In the wireless communication system shown in FIG. 1, data is transmitted from a transmitting device 10 to a receiving device 20 via a transmission path 30. The transmitting device 10 includes an ARQ processing unit 11, a transmitting unit 12, and a receiving unit 13. The receiving device 20 includes an ARQ processing unit 21, a receiving unit 22, a transmitting unit 23, a pre-stage buffer 24, and a post-stage buffer 25.

In this wireless communication system, first, transmission data is accumulated in the ARQ processing unit 11. The stored transmission data is subjected to a predetermined transmission process in the transmission section 12, and is transmitted to the reception-side apparatus 20. Then, the transmission data transmitted to the reception-side device 20 via the transmission path 30 is subjected to predetermined reception processing in the reception unit 22, Input to ARQ processing section 21.

The ARQ processing unit 21 performs error detection on the data subjected to the reception processing, and outputs an ACK (Acknowledgment) signal when no error is detected in the received data, and a NACK (Acknowledgment) signal when an error is detected. Negative Acknowledgment) signal to the transmitter 23. Here, if an error is detected in the data, the data is temporarily stored. Then, when the data is retransmitted, error detection is performed after combining the retransmitted data and the temporarily stored data.

When no error is detected, the ARQ processing section 21 generates an ACK signal as described above and stores the data in the preceding buffer 24. The first-stage buffer 24 temporarily stores the correctly received data, and outputs the accumulated data to the second-stage buffer 25 in accordance with a predetermined data order.

The transmission unit 23 performs a predetermined transmission process on the AC / NACK signal, and feeds back the signal to the transmitting apparatus 10. The ACK / NACK signal that has been fed back is subjected to predetermined reception processing in the reception unit 13 and input to the scale 0 processing unit 11. The ARQ processing unit 11 transmits the next transmission data when the ACK signal is input, and retransmits the previously transmitted transmission data when the NACK signal is input. By repeating the above operation, data communication is performed between the transmitting device 10 and the receiving device 20.

However, in the conventional wireless communication system, the data stored in the first-stage buffer 24 is output to the second-stage buffer 25 in a predetermined order, so that the data is correctly received until the data of a certain number is correctly received. Data subsequent to that number remains stored in the preceding buffer 24.

For example, as shown in FIG. 2, when a transmission data sequence Tx is transmitted from the transmission device 10 and a reception data sequence Rx is received by the reception device 20, the correctly received data # of the received data sequence For 1 to # 2, pre-buffer 2 4 can be transferred to the post-buffer 25. However, since data # 3 has not been received correctly, data # 4, # 5, etc. already received cannot be transferred from the first buffer 24 to the second buffer 25. In other words, in order to cope with the case where the time until the error of the data of a certain number is eliminated becomes longer, the capacity of the preceding buffer must be increased, and there is a problem that the device scale increases. Disclosure of the invention

An object of the present invention is to provide a data communication device and a data communication method capable of suppressing an increase in the buffer capacity of a communication partner device and preventing an increase in the scale of the communication partner device.

An object of the present invention is to calculate the distribution of the number of retransmissions of bucket data addressed to a communication partner device, and based on the calculated distribution of the number of retransmissions, to initialize the initial value of other bucket data addressed to the communication partner device. Achieved by controlling transmission. The inventor of the present invention has focused on the fact that packet data can be combined in the hybrid ARQ scheme, and that the error of the bucket data is eliminated when the reception quality of the combined packet data reaches a predetermined level. Reached.

According to one aspect of the present invention, a data communication device is a data communication device used in a wireless communication system to which a hybrid ARQ scheme is applied, and performs initial transmission of packet data addressed to a communication partner device, Transmission processing means for retransmitting the packet data when an error is detected in the packet data, calculating means for calculating a distribution of the number of times the packet data is retransmitted by the transmission processing means, Control for reducing the probability that an error is detected in the other bucket data at the communication partner device with respect to the initial transmission of the other bucket data addressed to the communication partner device performed by the transmission processing unit Or control to reduce the time required for the other communication device to eliminate the error in the other packet data, Retransmissions distribution that is And control means for performing based on.

According to another aspect of the present invention, a data communication method is a data communication method in a data communication device used in a wireless communication system to which a hybrid ARQ scheme is applied, wherein the initial transmission of bucket data addressed to a communication partner device is performed. Performing an initial transmission step, performing retransmission of the packet data when an error is detected in the packet data at the communication partner device, and performing retransmission of the bucket data in the retransmission step. A calculation step of calculating the distribution of the number of times, and a probability that an error is detected in the other packet data at the communication partner device with respect to the initial transmission of the other bucket data in the transmission processing step. Control, or shorten the time required until the error of the other packet data is eliminated in the communication partner device. His, and a control step of performing, based on the retransmission number distribution calculated by the calculation Sutetsu flop. Brief Description of Drawings

FIG. 1 is a block diagram illustrating an example of a configuration of a conventional wireless communication system. FIG. 2 is a diagram illustrating an example of an operation when data communication is performed in the conventional wireless communication system.

FIG. 3 is a block diagram illustrating a configuration of a base station apparatus according to Embodiment 1 of the present invention. FIG. 4 is a block diagram illustrating a configuration of a communication terminal apparatus that performs data communication with the base station apparatus according to Embodiment 1 of the present invention. Block diagram,

FIG. 5 is a diagram showing an example of a retransmission count distribution calculated in the base station apparatus according to Embodiment 1 of the present invention.

FIG. 6 is a diagram for explaining an example of an operation when the base station apparatus according to Embodiment 1 of the present invention performs data communication with a communication terminal apparatus,

FIG. 7 is a block diagram showing a configuration of a base station apparatus according to Embodiment 2 of the present invention, and FIG. 8 shows an example of a retransmission count distribution calculated in the base station apparatus according to Embodiment 2 of the present invention. FIG. BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the following, all embodiments will be described by taking as an example a case where the present invention is applied to a base station apparatus in a wireless communication system. '

(Embodiment 1)

FIG. 3 is a block diagram showing a configuration of the base station apparatus according to Embodiment 1 of the present invention.

The base station apparatus 100 shown in FIG. 3 includes an antenna 110, a transmission processing unit 120, a reception RF unit 130, an ACKZNACK signal extraction unit 1332, a retransmission count distribution calculation unit 134, a continuous transmission count determination unit 1 36 and an uncalculated detection section 138. Further, transmission processing section 120 includes CRC (Cyclic Redundancy Check) adding section 122, error correction encoding section 124, ARQ processing section 126, and transmission RF section 128. Base station apparatus 100 performs data communication with communication terminal apparatus 150 via a transmission path (not shown). As shown in FIG. 4, the communication terminal device 150 includes an antenna 152, a reception RF unit 154, a 10 processing unit 156, an error correction decoding unit 158, an error detection unit 160, and a pre-stage buffer 1. 62, a post-buffer 164, and a transmission RF unit, a small ACK / NACK signal generation unit 166.

〇1 The adding unit 122 adds a CRC to the transmission packet data (hereinafter, simply referred to as “data”) addressed to the communication terminal device 150 and inputs the CRC to the error correction coding unit 124. The error correction coding unit 124 performs error correction coding on the data output from the CRC adding unit 122, and inputs the data to the 0 processing unit 126.

The ARQ processing unit 126 performs error correction coding when the detection report is not received from the uncalculated detection unit 138 and the ACK signal reception is notified from the 0〇1 ^ signal extraction unit 132. The new data output from the unit 124 is input to the transmission RF unit 128 continuously for the number of times determined by the continuous transmission number determination unit 136. Hereinafter, new data output from the error correction encoding unit 124 will be referred to. The transmission processing performed by the transmission processing unit 120 is called “initial transmission”.

Further, when notified of the reception of the NACK signal from the ACKZNACK signal extraction unit 132, the 10 processing unit 126 transmits the data corresponding to the NACK signal output from the error correction encoding unit 124 to the transmission RF unit. 1 Enter in 28. Hereinafter, a transmission process performed by the transmission processing unit 120 on data output from the error correction encoding unit 124 and for which reception of the corresponding NACK signal has been notified is referred to as “retransmission”.

Also, 1 (3 The processing unit 126 inputs the target data to the transmission RF unit 128 continuously for a predetermined number of times when performing the initial transmission while the detection report is received from the uncalculated detection unit 138. As a result, even when a suitable distribution of the number of retransmissions (distribution of the number of retransmissions performed by the transmission processing unit 120) is not calculated, for example, at the start of data communication, the NACK signal from the communication terminal apparatus 150 is not calculated. In addition to reducing the probability of continuous reception of, the retransmission count distribution calculation unit 134 can calculate the retransmission count distribution, and can reduce the time required until the error is resolved.

The transmission RF section 128 performs predetermined radio transmission processing including digital-to-analog conversion and up-comparison on the data output from the ARQ processing section 126, and transmits the data wirelessly via the antenna 110.

The reception RF section 130 receives a radio signal via the antenna 110, performs predetermined radio reception processing including down-comparison / analog / digital conversion, etc., and inputs the ACK / NACK signal extraction section 132 to the ACK / NACK signal extraction section 132. I do.

The ACKZNACK signal extraction unit 132 extracts an ACK / N ACK signal wirelessly transmitted from the communication terminal device 150 from the wireless reception signal output from the reception RF unit 130. If the extracted signal is an ACK signal, the reception of the ACK signal is notified to the ARQ processing unit 126 and the retransmission count distribution calculation unit 134, while if the extracted signal is a NACK reception, the reception of the NACK signal is ARQ The processing unit 126 and the retransmission count distribution calculating unit 134 are notified. Retransmission count distribution calculating section 134 calculates the retransmission count distribution based on the notification result from ACK / NACK signal extraction section 132. More specifically, statistics on the number of retransmissions performed on certain data are taken. As a result, for example, a retransmission count distribution as shown in FIG. 5 is calculated. In the example of the distribution of the number of retransmissions shown in Fig. 5, the ratio of one retransmission is 2%, the ratio of two retransmissions is 5%, the ratio of three retransmissions is 86%, and the ratio of four retransmissions is four. The ratio is 5%, and the ratio of 5 times is 2. /. It is. In this example, the average number of retransmissions is 3, and the standard deviation is 0.5. Based on the retransmission count distribution calculated by the retransmission count distribution calculation unit 134, the continuous transmission count determination unit 1336 determines the number of continuous transmissions, which is one of the information indicating the radio resources, in the initial transmission, that is, the data Is determined, and the determined number is input to the ARQ processing unit 126.

For example, when the retransmission count distribution calculation section 13 4 calculates the retransmission count distribution shown in FIG. 5, the minimum retransmission count is larger than the difference “2.5” between the average retransmission count “3” and the standard deviation “0.5”. Since the integer of “3” is “3”, the number of continuous data transmissions is determined to be “3”.

The non-calculation detecting unit 1338 detects that an appropriate (highly reliable) retransmission count distribution has not been calculated by the retransmission count distribution calculating unit 134. The non-calculation detecting unit 1338 outputs the detection result to the ARQ processing unit 12 while it is detected that an appropriate retransmission number distribution is not calculated, that is, until an appropriate retransmission number distribution is calculated. Notify 6. For example, when data communication is started between base station apparatus 100 and communication terminal apparatus 150, an appropriate retransmission number distribution has not been calculated.

In communication terminal apparatus 150 that performs data communication with base station apparatus 100 having the above configuration, reception RF section 154 transmits data wirelessly transmitted from base station apparatus 100 to antenna 150. And performs predetermined radio reception processing including down-conversion and analog-to-digital conversion, and inputs the result to the ARQ processing unit 156. 1 (3 The processing unit 156, upon receiving the data output from the receiving RF unit 154, determines whether or not the same data as the data is stored therein. As a result of this determination, When the same data as the data is not stored, the data is temporarily stored therein, while when the same data is stored, the data received from the reception RF unit 154 is stored. Is combined with the same stored data, and the combined data is temporarily stored therein.The 10 processing unit 156 receives the data output from the reception RF unit 154 when receiving the data. If it is determined that the data is not being continuously transmitted, if the data is not being continuously transmitted, the same data as the temporarily stored data is corrected. Input to the decoding unit 1 58. On the other hand, If the data is data being continuously transmitted, the data received from the reception RF unit 154 is combined with the same data stored immediately before, and the combined data is temporarily stored inside, It is input to error correction decoding section 158. At this time, the number of times continuous reception data is synthesized is counted, and the counted number of times of synthesis is input to AC KZN ACK signal generation section 166.

The error correction decoding section 158 performs error correction decoding on the data output from the 1 ^ 0 processing section 156 and inputs the data to the error detection section 160.

The error detection unit 160 performs (3) error detection on the data output from the processing unit 156. If no error is detected in the data as a result of this error detection, the ACK / NACK signal In addition to notifying the generation unit 166, the data is stored in the pre-stage buffer 16 2. On the other hand, if an error is detected in the data, the fact is notified to the ACKZNACK signal generation unit 166, and the data Is not stored in the first buffer 162.

The first-stage buffer 162 refers to the number previously assigned to the data accumulated by the error detection unit 160, and moves the data to the second-stage buffer 164 according to the order of the assigned numbers, and accumulates the data. The data stored in the subsequent buffer 164 is subjected to predetermined signal processing as received data. The / 0 signal generation unit 166 generates an ACKZNACK signal according to the error detection result notified from the error detection unit 160. That is, when it is notified that an error has been detected, a NACK signal is generated and input to the transmission RF section 168. On the other hand, when it is notified that no error is detected, an ACK signal is generated and input to the transmission RF section 168. Further, at this time, it is determined whether or not the data corresponding to the error detection result is data being continuously transmitted. If the result of this determination is that the data is data being continuously transmitted, the number of times of combining required until no error is detected is transmitted at the same time.

The transmission RF section 168 performs predetermined radio transmission processing including digital-to-analog conversion and up-conversion on the ACKZNACK signal output from the ACKZNACK signal generation section 166, and transmits the base station apparatus via an antenna 152. Send to 100.

Next, an operation when base station apparatus 100 having the above configuration performs data communication with communication terminal apparatus 150 will be described. FIG. 6 is a diagram illustrating an example of an operation when base station 100 performs data communication with communication terminal apparatus 150. In the example described here, the time required from data transmission to retransmission, that is, RTT (Round Trip Time) is 6 packets. Also, here, the description is given on the assumption that the number of times S is “3” determined by the continuous transmission number determination unit 136.

As shown in FIG. 6, base station apparatus 100 transmits transmission data sequence Tx, and communication terminal apparatus 150 receives reception data sequence Rx. In this data communication, for example, data # 1, # 3, and # 4 are correctly received without errors since the transmission is repeated three times in the initial transmission. Also, for example, for data # 2, although errors have been detected in the initial transmission even though transmission has been repeated three times, the error is eliminated by performing one retransmission.

That is, for data # 2, one transmission and three retransmissions conventionally Can be assumed to be needed. In this case, it is considered that the time required for the error to be resolved was 24 (= 6 packets X 4 times) packets. In contrast, in the example of Fig. 6, three consecutive transmissions and one retransmission were performed, so the time required for the error to be resolved was' 9 (3 packets + 6 packets X 1 Times) shortened to packets.

As described above, according to the present embodiment, the number of retransmissions is calculated, and the number of continuous transmissions in the initial transmission is determined based on the calculated distribution of the number of retransmissions. And the time required for the error to be eliminated can be reduced, and the increase in the capacity of the pre-stage buffer 162 provided in the communication terminal device 150 can be suppressed. An increase in the scale of 50 can be prevented.

In the present embodiment, the present invention is applied to a base station apparatus. However, the same operation and effect as described above can be achieved by applying the present invention to a communication terminal apparatus that performs data communication with the base station apparatus.

(Embodiment 2)

FIG. 7 is a block diagram showing a configuration of a base station apparatus according to Embodiment 2 of the present invention. The base station apparatus according to the present embodiment has the same basic configuration as base station apparatus 100 described in Embodiment 1, and the same components are denoted by the same reference numerals. And a detailed description thereof will be omitted.

Base station apparatus 200 shown in FIG. 7 includes transmission processing section 210 and transmission power determining section instead of transmission processing section 120 and continuous transmission count determining section 132 described in Embodiment 1. 2 2 0. The transmission processing unit 210 includes an ARQ processing unit 212 and a transmission RF unit 214 instead of the ARQ processing unit 126 and the transmission RF unit 128 of the transmission processing unit 120. Base station apparatus 200 performs data communication with communication terminal apparatus 150 described in the first embodiment.

The ARQ processing section 212 receives the ACK signal from the 1/800 signal extraction section 132 when the detection report is not received from the uncalculated detection section 1338. If notified, the new data output from the error correction encoding unit 124 is input to the transmission RF unit 214. Further, when notified of the NACK signal reception from the ACK / NACK signal extraction unit 13 2, the 10 processing unit 2 12 2 transmits data corresponding to the NACK signal output from the error correction coding unit 124. Is input to the transmission RF section 214.

In addition, when the ARQ processing unit 212 performs the initial transmission during the period in which the detection report is received from the uncalculated detection unit 1338, the ARQ processing unit 212 inputs the target data to the transmission RF unit 214 continuously for a predetermined number of times. By this means, even in a situation where an appropriate distribution of the number of retransmissions has not been calculated, for example, at the start of data communication, the probability of continuously receiving NACK signals from communication terminal apparatus 150 can be reduced, and the number of distributions of retransmission number calculation section 134 The retransmission count distribution can be calculated by using, and the time required until the error is eliminated can be shortened.

Transmission power determination section 220 determines transmission power, which is one of the information indicating the radio resources, in the initial transmission based on the retransmission number distribution calculated by retransmission number distribution calculating section 134, and determines the determined transmission power. Is input to the transmission RF section 214.

For example, it is assumed that the retransmission count distribution calculation section 134 has calculated the retransmission count distribution shown in FIG. In this example of the distribution of the number of retransmissions, the rate of 1 retransmission and the rate of 7 retransmissions are 5%, respectively, the rate of 2 retransmissions and the rate of 6 retransmissions are 15%, respectively, and the rate of 3 retransmissions is 3%. The ratio, the ratio of 4 times and the ratio of 5 times are each 20%. In this example, the average number of retransmissions is 4, and the standard deviation is 1.58. In this case, the transmission power determination unit 220 determines that the minimum integer greater than the difference “2.42” between the average number of retransmissions “4” and the standard deviation “1.58” is “3”. Is determined to be "3" times the normal value.

The transmission RF section 214 performs predetermined radio transmission processing including digital-to-analog conversion and up-comparison on the data output from the ARQ processing section 212, and performs radio transmission via the antenna 110. I do. The transmission power determination unit 220 The data is amplified so that the wireless transmission of data is performed at the transmission power determined by.

As described above, according to the present embodiment, an error is detected in communication terminal apparatus 150 because the distribution of the number of retransmissions is calculated and the transmission power in the initial transmission is determined based on the calculated distribution of the number of retransmissions. It is possible to reduce the probability and reduce the time required for the error to be eliminated, to suppress the increase in the capacity of the pre-stage buffer 162 provided in the communication terminal device 150, and to reduce the capacity of the communication terminal device 150. An increase in scale can be prevented.

As described above, according to the present invention, an increase in the buffer capacity of a communication partner device can be suppressed, and an increase in the scale of the communication partner device can be prevented.

The present specification is based on Japanese Patent Application No. 2003-278391 filed on July 23, 2003. All this content is included here. Industrial applicability

A data communication device and a data communication method according to the present invention have an effect of suppressing an increase in buffer capacity of a communication partner device and preventing an increase in the size of the communication partner device, and a wireless communication system to which the hybrid ARQ scheme is applied. The present invention is useful as a data communication device and a data communication method used for the communication.

Claims

The scope of the claims

1. A data communication device used in a wireless communication system to which the hybrid ARQ method is applied,

Transmission processing means for performing initial transmission of packet data addressed to the communication partner device, and retransmitting the packet data when an error is detected in the packet data at the communication partner device;

Calculating means for calculating a distribution of the number of times the packet data is retransmitted by the transmission processing means;

Control for reducing the probability that an error is detected in the other bucket data at the communication partner device with respect to the initial transmission of another bucket data addressed to the communication partner device performed by the transmission processing means, or Control means for performing control to reduce the time required until the error of the other packet data is eliminated in the communication partner device based on the calculated retransmission count distribution,

A data communication device having:

2. The control means includes:

2. The data communication device according to claim 1, wherein in the initial transmission of the other packet data by the transmission processing unit, the number of times of continuously transmitting the other packet data is determined.

3. The control means includes:

2. The data communication device according to claim 1, wherein the transmission processing unit adjusts transmission power when the other packet data is initially transmitted.

4. It further comprises a detecting means for detecting that the retransmission number distribution is not calculated by the calculating means,

The transmission processing means,

When it is detected that the distribution of the number of retransmissions has not been calculated, the bucket data is transmitted a predetermined number of times continuously in the initial transmission of the bucket data. The data communication device according to claim 1.

5. A data communication method in a data communication device used in a wireless communication system to which the hybrid ARQ scheme is applied,

An initial transmission step of performing initial transmission of bucket data addressed to the communication partner device; and a retransmission step of retransmitting the packet data when an error is detected in the packet data at the communication partner device.

A calculating step of calculating a distribution of the number of times the packet data is retransmitted in the retransmitting step;

Control for reducing the probability of detecting an error in the other bucket data at the communication partner device with respect to the initial transmission of the other bucket data in the transmission processing step; or A control step of reducing the time required until the error of the other packet data is eliminated based on the retransmission count distribution calculated in the calculation step,

A data communication method comprising: