CN1355630A

CN1355630A - Method based on mixed turbo code for automatically receiving retry request

Info

Publication number: CN1355630A
Application number: CN 00127597
Authority: CN
Inventors: 苏宁
Original assignee: Huawei Technologies Co Ltd
Current assignee: Huawei Technologies Co Ltd
Priority date: 2000-11-28
Filing date: 2000-11-28
Publication date: 2002-06-26
Anticipated expiration: 2020-11-28
Also published as: CN1114297C

Abstract

A receiving method based on a turbo code hybrid automatic retransmission request: judge whether the received data packet is a data packet requesting retransmission; if not, the prior information is initially 0, and the normal data is decoded; if it is, it is judged whether to and Combination of failed data packets: if not combined, same as above; if combined, set a priori information as the decoding output soft information of the failed data packet, and decode it together with the retransmitted data packet; learn from it whether the decoding is correct: if it is correct, the identification is successful, and the feedback End; if it fails, judge whether to combine it with the retransmission data packet next time: if it is, keep the decoding output soft information of the failed data packet; otherwise, discard it; mark failure, feedback, request retransmission, and end.

Description

A kind of based on spy's yard method of reseptance of mixed automatic retransmission request of fighting

The present invention relates to a kind of method of reseptance of automatic re-send request may, relate in particular to a kind of based on spy's yard method of reseptance of mixed automatic retransmission request of fighting.

Radio communication is owing to the inhomogeneities and the unsteadiness of transmission medium, and the signal of transmission can be subjected to interference effects such as time diffusion, decline, causes the mistake of the peculiar randomness of ratio of reception.Therefore need to come the opposing interference effect by certain methods.

Method commonly used is to add channel coding/decoding, and the decoding that increases redundant and recipient by the coding in emission side reaches the error correction purpose.For example, Turbo code (spy fight sign indicating number) is the very strong sign indicating number of a kind of error correcting capability.Its encoder is to be made of the mode of two or more sub-encoders by serial or parallel connection, usually more general Turbo code encoder is to be formed in parallel by two convolution code sub-encoders, sub-encoders is directly sent in input information position one tunnel, another road is through sending into another sub-encoders coding behind the interleaver, punching is modulated to suitable code check output to the data after having compiled through card punch again.The Turbo code encoder of advising in WCDMA (WCDMA) and CDMA2000 (CDMA 2000) motion is made of two encoders parallel connections.

Fig. 1 is the structure of the Turbo code encoder in the CDMA2000 motion, it comprises two sub-encoders 14,16, interleaver 12 and card punch 18 up and down, its effect is that the order of input data is carried out layout again, purpose is to adjust the distribution of weight, make weight distribution and another sub-encoders 14 different of a sub-encoders 16 incoming bit streams, and to six road bits of two sub-encoders outputs punch sampling and and string conversion.

The decoding of Turbo code can be adopted maximum likelihood method decoding (for example SOVA algorithm), also can adopt maximum posteriori decoding (MAP) algorithm, and these two kinds of methods all are used for the recursive iteration mode in the Turbo decoding.Fig. 2 is the structure of Turbo code decoder, and it comprises soft inputting and soft output decoder (SISO) 23,24, separate perforating device 21, two deinterleavers 22, two interleavers 26 and symbol judgement devices 25.Separate the inverse operation of perforating device 21 corresponding to card punch 18, deinterleaver 22 is corresponding to the inverse operation of interleaver 26, the order before reduction interweaves, symbol judgement device 25, when the input data more than or equal to 0 the time, output 1; When the input data less than 0 the time, output 0.

Turbo code causes time delay bigger owing to need interweave and iterative decoding, therefore is applied in usually in the real-time less demanding data transmission service.All adopted the channel coding/decoding mode of the Turbo code of parallel cascade in WCDMA and the CDMA2000 standard as data service.

For data service, on above-mentioned channel, increase Turbo code and resist the interference as error correcting code, also can pass through arq (ARQ, Auto Repeat Request) method and guarantee the reliability transmitted.

This ARQ method is: the sign that feeds back to success of transmit leg or failure after the recipient judges through the solution code check the packet of each reception, when being designated failure, transmit leg need to resend the packet that is designated bust this (calling the mistake bag).The sign failure realizes by add CRC (CRC) check information in coded message.Come the judgment data bag whether to decode correctly by CRC check information during decoding.

Example in wireless communication system, for example in the WCDMA system, that adopt for data service is mixed automatic retransmission request (HAQR, Hybrid Auto Repeat Request), and following several mode is arranged:

1. according to the decoded packet data of retransmitting, the miss data bag abandons;

2. do not abandon the miss data bag, the packet of repeating transmission is the same with the transmission information that previous miss data bag comprises, and retransmission data bag and miss data bag maximize merging according to signal to noise ratio, the decoded packet data after being combined;

3. increment is retransmitted, and compares with mode 2, and the packet of repeating transmission contains more redundancy than the packet of the previous failure of sending out.The packet combining that this mode does not need and fails;

4. the part increment is retransmitted, and compares with mode 3, and a repeating transmission increases redundant part, and therefore the packet of repeating transmission is common littler than the previous packet of sending out, need be by decoding with the combination of miss data bag during decoding.

By HARQ, can guarantee the transmission quality of data.Mode 2,3,4 can benefit time diversity by merging, and becomes decline during opposing.

Need to keep the before packet of failure but merge, for example, frame length is the information source data of L, through after the chnnel coding, for the R=1/3 code check, needs to keep the soft value of information of the individual miss data bag of 3L, can cause like this anxiety of memory space resource.

The object of the present invention is to provide a kind of method of reseptance based on the request of Turbo code mixed automatic retransmission that can improve systematic function, reduce memory space.

To achieve these goals, a kind of method of reseptance based on the request of Turbo code mixed automatic retransmission provided by the present invention, included step is: for the packet that comprises Turbo code coding and other control information that receives, judge at first whether this packet belongs to the packet of request repeat, to determine Turbo code prior information and decoded data packets: if not, then, the Turbo code prior information is initially 0, and the data that normally receive enter decoding as decoded data packets; If, then further judge whether according to a preconcerted arrangement to require with the previous miss data inclusion that keeps of retransmission data bag and correspondence also: if do not require merging, then, the Turbo code prior information is initially 0, and the data that normally receive enter decoding as decoded data packets; If require to merge, then, put the Turbo code prior information and export soft information for the decoding of retransmitting miss data bag corresponding to packet, and this Turbo code prior information and retransmission data bag are together entered decoding as decoded data packets; The decoded data packets of determining is decoded, and learn according to the CRC that contains in the decoded data packets whether decoded data packets decoding is correct: if this decoded packet data is correct, then identify the decoded data packets transmission success, and after transmit leg feedback sign, finish; If the failure of this decoded packet data, then further judge according to a preconcerted arrangement whether need next time with the retransmission data inclusion also: if soft information is exported in the decoding that then keeps the packet of current failure; If not, soft information is exported in the decoding that then abandons the packet of current failure; Simultaneously, the bust this of sign decoded data packets, and to transmit leg feedback sign, request repeat finishes.

Owing to utilized the soft information of output of miss data bag as the prior information of retransmission data bag decoding, can improve the performance of Turbo decoding.Under same decoding iterations restriction, the introducing of prior information roughly has been equivalent to increase again the iterations that equates on original iterations, thereby has improved performance.And if system's capable of regulating iterations, then decoding to reach by less iteration the error code requirement under the help of prior information, thereby has reduced decode time.Simultaneously on memory space, have to merge the information that the HARQ mechanism that requires needs to keep length behind the data packet coding, and the R that the reservation of prior information only has data packet length doubly (R is code check, for example 1/3).And as prior information, the reservation of its precision can be no more than the precision of receive data bag.Compare with the memory space that keeps the miss data bag, keep the needed memory space of the soft information of decoding and want little several times, can solve and retransmit the most irritating storage problem in the merging mechanism among the HARQ.

The present invention is further illustrated below in conjunction with accompanying drawing.

Fig. 1 is the structure chart of existing Turbo code encoder;

Fig. 2 is the structure chart of existing Turbo code decoder;

Fig. 3 is a flow chart of the present invention.

As shown in Figure 3, of the present invention a kind of based on spy's yard method of reseptance of mixed automatic retransmission request of fighting, comprise the fight packet of sign indicating number coding and other control information of spy for what receive, at first judge whether it is the packet of request repeat, if not, then the Turbo code prior information is initially 0, and the data that normally receive are sent into decoder decode; If then whether require retransmission data bag and the corresponding previous miss data inclusion that keeps also according to the HARQ judgment mechanism: if do not require merging, then the Turbo code prior information is initially 0, and the data that normally receive are sent into decoder decode; If HARQ mechanism requires retransmission data bag and miss data inclusion also, the soft information of output of the miss data bag of the previous reservation of taking-up retransmission data bag correspondence is sent into the Turbo code decoder decode as the prior information and the retransmission data bag of Turbo code decoder;

The Turbo code decoder is decoded to each packet (no matter whether merged, and whether contained prior information) of input.Contain CRC check information in the information of decoding, can know by CRC check information whether packet decodes correctly, if this decoded packet data is correct, then the identification data packet transmission success finishes after the correct information of emission side's feedback decoding; If this packet belongs to the packet of failure, require to judge whether that according to the merging of HARQ mechanism the decoding that needs keep the miss data bag exports soft information, if need to be when retransmitting and the retransmission data inclusion also, soft information is exported in the decoding that then keeps current miss data bag; Otherwise soft information is exported in the decoding that abandons the miss data bag.Packet for failure needs the identification data packet bust this, retransmits to the transmit leg feedback request.

In sum, the present invention is directed to the Turbo code encoding and decoding under the HARQ mechanism, when the decoding of retransmission data bag, the soft value of information of utilizing the decoding of previous miss data bag to obtain is as the prior information of the increase of retransmission data bag decoding.This method can improve decoding performance and reduce decode time in the situation of not utilizing the miss data bag, and only increases limited amount memory space.

Claims

1. one kind based on spy's yard method of reseptance of mixed automatic retransmission request of fighting, and it is characterized in that, comprises the following steps:

Comprise the fight packet of sign indicating number coding and other control information of spy for what receive, judge at first whether this packet belongs to the packet of request repeat, to determine spy fight yard prior information and decoded data packets:

If not, then, spy's yard prior information of fighting is initially 0, and the data that normally receive enter decoding as decoded data packets;

If then further judge whether according to a preconcerted arrangement to require also with the previous miss data inclusion that keeps of retransmission data bag and correspondence:

If do not require merging, then, spy's yard prior information of fighting is initially 0, and the data that normally receive enter decoding as decoded data packets;

If require to merge, then, put spy's yard prior information of fighting and export soft information for the decoding of retransmitting miss data bag corresponding to packet, and fight yard prior information and retransmission data bag of this spy together entered decoding as decoded data packets;

The decoded data packets of determining is decoded, and learns according to the CRC that contains in the decoded data packets whether the decoded data packets decoding is correct:

If this decoded packet data is correct, then identifies the decoded data packets transmission success, and finish to transmit leg feedback sign back;

If the failure of this decoded packet data, then further judge according to a preconcerted arrangement whether need next time with the retransmission data inclusion also:

If so, soft information is exported in the decoding that then keeps the packet of current failure;

If not, soft information is exported in the decoding that then abandons the packet of current failure;

Simultaneously, the bust this of sign decoded data packets, and to transmit leg feedback sign, request repeat finishes.