CN101615986A - A data transmission method, device and communication system - Google Patents

Abstract

The embodiment of the present invention discloses a data transmission method, including: dividing the transmission block into at least one group, each group contains at least one coding block; adding a cyclic redundancy CRC check bit to each group; sending the added CRC check bit The post-check group. At the same time, the embodiment of the present invention discloses a data transmission device and a communication system based on the idea of grouping, and retransmits the group corresponding to the verification error, which greatly reduces the amount of data retransmission and obtains a large throughput gain at the same time.

Description

A data transmission method, device and communication system

technical field

The present invention relates to the communication field, in particular to a data transmission method, a data transmission device and a communication system.

Background technique

In the field of communication and computer, the data frame composed of "0" and "1" is generally used for transmission and storage, and the transmission channel is generally damaged. In order to check the correctness of received data, the current method is to add correctness check information in the transmitted data frame. This method is called Cyclic Redundancy Check (CRC check for short).

In the 802.16e protocol, when the number of bits of a burst burst is greater than 4800 bits after adding CRC check bits and padding bits, it will be divided into multiple coded blocks and encoded separately during encoding, and the coded blocks will be encoded before modulation Connect according to the order of division, see Figure 1.

If one or more encoded blocks are decoded incorrectly at the receiving end, the CRC check shows that an error occurred in the transmission block, the receiving end requests to resend the data through Automatic Repeat Request (ARQ), and the sending end receives the ARQ request to retransmit the entire The transmission block and the retransmission process are shown in Figure 2.

If any coding block in the transmission block is decoded incorrectly, it will appear as a decoding error of the entire transmission block during retransmission, and it is impossible to determine which coding block is wrong, and the entire transmission block needs to be retransmitted during retransmission, resulting in waste of resources and throughput performance Decline.

Contents of the invention

The embodiment of the present invention proposes a new data transmission method, device and system based on the deficiencies mentioned in the prior art.

A data transmission method comprising:

dividing the transport blocks into at least one group, each group containing at least one coded block;

Add a cyclic redundancy CRC check bit for each group;

Send the group after adding the CRC check digit.

Correspondingly, an embodiment of the present invention provides a data transmission device, including:

a segmentation module for dividing the transport block into at least one group, each group containing at least one coding block;

A preprocessing module, for adding a CRC check digit to each group divided into by the segmentation module;

A data sending module, configured to send the data preprocessed by the preprocessing module.

In addition, an embodiment of the present invention also provides a communication system, including a transmitter, communicating with a receiver, wherein:

The transmitter is used to divide the transmission block into at least one group, each group contains at least one coding block, add a CRC check bit to each group, encode, preprocess and send.

In the embodiment of the present invention, several coded blocks are formed into a coded block group, and CRC is added to each coded block group. When one or more coded block transmission errors occur, it is only necessary to retransmit the erroneous group instead of retransmitting the entire transmission block. The amount of data retransmission and feedback overhead are reduced.

Description of drawings

Fig. 1 is the schematic diagram of CRC addition method in existing 802.16 agreement;

Fig. 2 is a schematic diagram of the retransmission process in the existing 802.16 protocol;

FIG. 3 is a first schematic diagram of a segmentation method according to an embodiment of the present invention;

Fig. 4 is a second schematic diagram of the segmentation method of the embodiment of the present invention;

FIG. 5 is a structural block diagram of a data transmission device according to an embodiment of the present invention.

Detailed ways

Below in conjunction with accompanying drawing and embodiment, the specific embodiment of the present invention is described in further detail:

An embodiment of the present invention provides a data transmission method, the transmission block includes at least one group, and each group includes at least one coding block; a cyclic redundancy CRC check bit is added to each group, and the added CRC check bit is sent group after.

As shown in Figure 3, the transmission block is divided into multiple coding blocks (Code Block), and several coding blocks are formed into a group (group). The number of groups contained in one transport block is greater than or equal to 1, and the number of coding blocks contained in each group is greater than or equal to 1. A CRC is added to each group.

In addition, the transmission block can also be divided into multiple groups, CRC check bits are added to each group, and each group is divided into one or more coding blocks. As shown in Figure 4.

The length of each coding block in the above method includes the following situations: the numbers of coding blocks in different groups are the same/different, and the lengths of coding blocks in different groups are the same/different.

When grouping, the scheme of using the same length of each coding block is as follows:

Let the transmission block size be B, divide the transmission block into N _Cblock coding blocks, the number of groups is N _group , the number of CRC check bits added to each group is N _CRC , and the number of coding blocks in each coding block group is the same, If the size of the coding block is the same, the average number of bits per coding block can be obtained as follows:

$\mathrm{<span\; class="notranslate">\; N</span>}<span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; B</span>}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; N</span>}}_{\mathrm{<span\; class="notranslate">\; group</span>}}<span\; class="notranslate">\; \&CenterDot;</span>{\mathrm{<span\; class="notranslate">\; N</span>}}_{\mathrm{<span\; class="notranslate">\; CRC</span>}}}{{\mathrm{<span\; class="notranslate">\; N</span>}}_{\mathrm{<span\; class="notranslate">\; C\; block</span>}}}$

N may be a decimal instead of an integer. According to the limitation of the encoder, padding bits are added. Taking the CTC encoder as an example, the actual encoding block size is:

N _b =ceil(N)+paddingbit=8*M, M is an integer

Wherein, ceil represents rounding up, and N _b is an integer multiple of 8.

In a Hybrid Automatic Repeat (HARQ) channel, if one or more coded block groups are decoded incorrectly at the receiving end, based on group feedback ACK/NACK, the sending end only needs to retransmit the error group.

Similarly, the number of groups is N _group , and the number of CRC check bits added by each group is N _CRC . The number of coded blocks in each coded block group can be different, and the size of the coded blocks is inconsistent. The size of each coded block varies with the actual It depends.

In grouping, the principle of unequal number of groups can be adopted. As shown in Table 1 below, different groups can be used to obtain different gains for different transport block lengths. When grouping, the most reasonable gain can be obtained by using different numbers of groups according to different transport block sizes. The following grouping scheme can be made in advance:

TBsize(bit) 1～4800 4801～9600 9601～14400 14401～19200 19201～24000 24001～28800 28801～33600 33601～38400 38401～43200 43201～48000 groups 1 2 3 3 3 3 3 4 4 4

Table 1 Schemes with different numbers of packets of different transport block lengths

For example, if the length of the transmission block is 20000 bits, the transmission block is divided into 3 groups; if the length of the transmission block is 40000 bits, the transmission block is divided into 4 groups.

Since the probability of multiple retransmissions is relatively small, the retransmission gain mainly comes from the first retransmission, so the throughput of the present invention can be analyzed by only considering the first transmission and the first retransmission.

Assuming that the error probability of transmission block transmission is _Pe , the transmission block is divided into N _Cblock coding blocks, and the length of each coding block is N _b . Divide the transmission block into N _groups , and the CRC check bits added to each group have N _CRC check bits, then each group has $N_{\mathrm{cpg}}=\frac{N_{\mathrm{C\; block}}}{N_{\mathrm{group}}}$ coded blocks with N _{b_group} =N _b ·N _cpg bits.

Then the probability of error for each group is: $P_{e\_\mathrm{group}}=1-{(1-P_e)}^{\frac{1}{N_{\mathrm{group}}}}$

For the grouping scheme in the existing 802.16e protocol, in one transmission and one retransmission, the number of correctly transmitted information per resource unit is: $\frac{N_{b\_\mathrm{group}}\&Center\; Dot;N_{\mathrm{group}}-N_{\mathrm{CRC}}}{(N_{b\_\mathrm{group}}\&Center\; Dot;N_{\mathrm{group}})\&Center\; Dot;(1+P_e)}.$

In one transmission and one retransmission in the embodiment of the present invention, the number of correctly transmitted information on each resource unit is: $\frac{N_{b\_\mathrm{group}}\&Center\; Dot;N_{\mathrm{group}}-N_{\mathrm{CRC}}\&Center\; Dot;N_{\mathrm{group}}}{(N_{b\_\mathrm{group}}\&CenterDot;N_{\mathrm{group}})\&CenterDot;(1+P_{\text{e\_group}})}$

Compared with the grouping scheme in the existing 802.16e protocol, the throughput gain obtained is:

$\mathrm{<span\; class="notranslate">\; r</span>}<span\; class="notranslate">\; =</span>\frac{\frac{{\mathrm{<span\; class="notranslate">\; N</span>}}_{\mathrm{<span\; class="notranslate">\; b</span>}<span\; class="notranslate">\; \_</span>\mathrm{<span\; class="notranslate">\; group</span>}}<span\; class="notranslate">\; \&Center\; Dot;</span>{\mathrm{<span\; class="notranslate">\; N</span>}}_{\mathrm{<span\; class="notranslate">\; group</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; N</span>}}_{\mathrm{<span\; class="notranslate">\; CRC</span>}}<span\; class="notranslate">\; \&Center\; Dot;</span>{\mathrm{<span\; class="notranslate">\; N</span>}}_{\mathrm{<span\; class="notranslate">\; group</span>}}}{<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; N</span>}}_{\mathrm{<span\; class="notranslate">\; b</span>}<span\; class="notranslate">\; \_</span>\mathrm{<span\; class="notranslate">\; group</span>}}<span\; class="notranslate">\; \&Center\; Dot;</span>{\mathrm{<span\; class="notranslate">\; N</span>}}_{\mathrm{<span\; class="notranslate">\; group</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; \&Center\; Dot;</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; e</span>}<span\; class="notranslate">\; \_</span>\mathrm{<span\; class="notranslate">\; group</span>}}<span\; class="notranslate">\; )</span>}}{\frac{{\mathrm{<span\; class="notranslate">\; N</span>}}_{\mathrm{<span\; class="notranslate">\; b</span>}<span\; class="notranslate">\; \_</span>\mathrm{<span\; class="notranslate">\; group</span>}}<span\; class="notranslate">\; \&Center\; Dot;</span>{\mathrm{<span\; class="notranslate">\; N</span>}}_{\mathrm{<span\; class="notranslate">\; group</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; N</span>}}_{\mathrm{<span\; class="notranslate">\; CRC</span>}}}{<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; N</span>}}_{\mathrm{<span\; class="notranslate">\; b</span>}<span\; class="notranslate">\; \_</span>\mathrm{<span\; class="notranslate">\; group</span>}}<span\; class="notranslate">\; \&Center\; Dot;</span>{\mathrm{<span\; class="notranslate">\; N</span>}}_{\mathrm{<span\; class="notranslate">\; group</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; \&Center\; Dot;</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; e</span>}}<span\; class="notranslate">\; )</span>}}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; =</span>\frac{{\mathrm{<span\; class="notranslate">\; N</span>}}_{\mathrm{<span\; class="notranslate">\; b</span>}<span\; class="notranslate">\; \_</span>\mathrm{<span\; class="notranslate">\; group</span>}}<span\; class="notranslate">\; \&Center\; Dot;</span>{\mathrm{<span\; class="notranslate">\; N</span>}}_{\mathrm{<span\; class="notranslate">\; group</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; N</span>}}_{\mathrm{<span\; class="notranslate">\; CRC</span>}}<span\; class="notranslate">\; \&CenterDot;</span>{\mathrm{<span\; class="notranslate">\; N</span>}}_{\mathrm{<span\; class="notranslate">\; group</span>}}}{{\mathrm{<span\; class="notranslate">\; N</span>}}_{\mathrm{<span\; class="notranslate">\; b</span>}<span\; class="notranslate">\; \_</span>\mathrm{<span\; class="notranslate">\; group</span>}}<span\; class="notranslate">\; \&Center\; Dot;</span>{\mathrm{<span\; class="notranslate">\; N</span>}}_{\mathrm{<span\; class="notranslate">\; group</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; N</span>}}_{\mathrm{<span\; class="notranslate">\; CRC</span>}}}<span\; class="notranslate">\; \&CenterDot;</span>\frac{\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; e</span>}}}{\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; e</span>}<span\; class="notranslate">\; \_</span>\mathrm{<span\; class="notranslate">\; group</span>}}}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; .</span>$

The specific assignment of the above formula results in the following table:

N _{b_group} N _group r(%)for2groups r(%)for3groups r(%)for4groups 4800 4.1049 \ \ 9600 4.3685 5.7975 \ 14400 4.456 5.9754 6.6759 19200 4.4997 6.0643 6.8103 24000 4.526 6.1176 6.8909 28800 4.5434 6.1531 6.9446 33600 4.5559 6.1785 6.983 38400 4.5653 6.1975 7.0117

43200 4.5725 6.2123 7.0341 48000 4.5784 6.2241 7.052

Table 2 Gains obtained by using different grouping schemes for different transport block lengths

It can be seen from the above table that the grouping method of the embodiment of the present invention has improved throughput performance, and the number of groups can be set to 2, 3 or 4 groups according to different encoding block sizes, which can be achieved without increasing the complexity. get higher gain.

An embodiment of the present invention provides a data transmission device based on the above grouping idea, as shown in FIG. 5 , including:

a segmentation module for dividing the transport block into at least one group, each group containing at least one coding block;

A preprocessing module, for adding a CRC check digit to each group divided into by the segmentation module;

A data sending module, configured to send the data preprocessed by the preprocessing module.

Further, the data sending module may include a retransmission module, configured to retransmit the error group when the data transmission error occurs.

It should be noted that the preprocessing here may include but not limited to interleaving, modulation processing, and precoding.

The embodiment of the present invention also provides a communication system based on the above-mentioned grouping idea, including a transmitter, communicating with a receiver, wherein:

a transmitter for dividing transport blocks into at least one group, each group containing at least one coded block, adding a CRC check bit to each group, encoding, preprocessing and sending said preprocessing including but not limited to interleaving , modulation processing, precoding.

The receiver is used to receive the data sent by the transmitter, check the correctness of the data, and feed back ACK or NACK instructions to the transmitter according to the group. Feed back one instruction per group instead of one instruction per encoding block.

When the transmitter receives a NACK command for each group, it retransmits the wrong group; when it receives an ACK command, it does not retransmit the corresponding group data.

The data transmission device in the embodiment of the present invention divides the data block to be transmitted into multiple groups, each group includes at least one data block, and when a transmission error occurs and needs to be retransmitted, the error group is retransmitted instead of the entire transmission block.

In the embodiment of the present invention, the transmission block is divided into at least one group, and a CRC is added to each group. When there are one or more coded block transmission errors, only the wrong group is retransmitted without retransmitting the entire transmission block, which greatly reduces data transmission. retransmission while obtaining a large throughput gain.

The modules in the embodiment of the present invention may be distributed in one device, or may be distributed in multiple devices. The above modules can be combined into one module, or can be further split into multiple sub-modules.

Those skilled in the art can understand that the drawing is only a schematic diagram of a preferred embodiment, and the modules in the drawing are not necessarily necessary for implementing the present invention.

The solutions described in the claims are also the scope of protection of the embodiments of the present invention.

Those skilled in the art can understand that all or part of the processing in the methods of the above embodiments can be completed by instructing related hardware through a program, and the program can be stored in a computer-readable storage medium.

The description of the above embodiments is only used to help understand the method and thought of the present invention; meanwhile, for those of ordinary skill in the art, according to the thought of the present invention, there will be changes in the specific implementation and scope of application. As mentioned above, the contents of this specification should not be construed as limiting the present invention.

Claims (9)

1, a kind of data transmission method is characterized in that, comprising:

Transmission block is divided at least one group, and each group comprises at least one encoding block;

For each group is added cyclic redundancy CRC check position;

Send the group behind the described interpolation CRC check position.

2, data transmission method according to claim 1 is characterized in that, the number of interior encoding block is not identical or different on the same group, and the length of each encoding block is identical or different.

3, data transmission method according to claim 1 is characterized in that, the group number that described transmission block is divided into is according to the preset amount of transmission block.

4, data transmission method according to claim 1 is characterized in that, during data transmission fault, retransmits the group of makeing mistakes.

5, a kind of data transmission device is characterized in that, comprising:

Segmentation module is used for transmission block is divided at least one group, and each group comprises at least one encoding block;

Pretreatment module, each group that is used for described segmentation module is divided into is added the CRC check position;

Data transmission blocks is used to send the group after described pretreatment module is added the CRC check position.

6, device according to claim 5 is characterized in that, described data transmission blocks further comprises: retransmission module when being used for data transmission fault, retransmits the group of makeing mistakes.

7, a kind of communication system comprises transmitter, communicates with receiver, it is characterized in that,

Described transmitter is used for transmission block is divided at least one group, and each group comprises at least one encoding block, for described each group is added CRC check position and transmission.

8, communication system according to claim 7 is characterized in that,

Described receiver is used for the data that receiver/transmitter sends, the correctness of the described data of verification, and correctly reply ACK or wrong responses NACK instructs to transmitter according to the group feedback.

9, communication system according to claim 8 is characterized in that, when described transmitter receives the NACK instruction, retransmits the group of makeing mistakes.

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