CN101060481A - A Turbo code transmission block segmenting method - Google Patents

Abstract

The disclosed segmenting method for Turbo code comprises: deciding whether the transmission block length over the system-set threshold; if equal or less than the threshold, using interlace device length KI for segmentation; or else, using near KI-1 and KI for segmentation. This invention ensures system performance, reduces filling-bit number, and decreases the complexity and time delay.

Description

A kind of segmentation method of Turbo code transmission block

Technical field

The present invention relates to chnnel coding and multiplexing method in a kind of digital communication system, the interleaver sizes that particularly relates to Turbo code employing in the communication system is the transmission block segmentation method under the situation about dispersing.

Background technology

In communication system, the reliability for raising information is transmitted in channel improves the antijamming capability of data on channel, needs to adopt corresponding channel coding technology.In many chnnel codings, the error correcting capability of Turbo code is stronger, can satisfy the requirement of high reliability data transmission.The Turbo coding is a kind of parallel cascade codes that has inner interleaver, and generally it is made of the identical recursive systematic convolutional code component code encoder of two structures of an interleaver parallel cascade.As shown in Figure 1.

In recent years along with the developing rapidly of high data rate, low delay, multiservice requirement, need satisfy high-throughput, low time delay, code length requirement flexibly as the Turbo decoder of critical component in the high speed multiservice system.

The Turbo decoder need adopt the decoding algorithm of high-speed parallel to improve processing speed.It is the multiple of degree of parallelism that the high-speed parallel decoding algorithm requires the length of Turbo code interleaver, that is to say that the length of Turbo code interleaver disperses.The discrete length set of establishing this length here and be the Turbo interleaver of degree of parallelism multiple is K _Table, K _TableMiddle element number is T, and minimum and maximum interleaver sizes is respectively Z _MinAnd Z _Max

Length for interleaver is the Turbo code of the multiple of degree of parallelism, if the length X of information block is not at interleaver sizes set K _TableIn, then need in information block " 0 " or " 1 " of filling some earlier, make total block length equal interleaver sizes, then could be by the Turbo encoder encodes.Need the system bits from code word directly to delete these filling bits behind the coding.And the filling bit corresponding check bit can also can need not be handled earlier directly by " (puncturing) punchinges " deletion, carries out the adjustment of code check and pass through " rate-matched (rate-matching) " unification.

During decoding, earlier insert the enough big value of an expression " 0 " or " 1 " in the systematic bits position of the correspondence of filling bit, the soft information of representing this place is 100% known.Pretreated like this received information sequence is admitted to decoder for decoding and deciphers by normal processes.At last, remove the information bit that corresponding dummy bits just obtains needs in the decode results.From decoder to the processing of filling bit as can be seen, filling bit has been equivalent to increase the length of information block, thereby can increase decoding complexity and decoding delay.

In the Base-Band Processing of wireless communication system, the form that physical layer collects with transmission block (Transport Block) receives the data flow from media access control sublayer, and these data flow after Base-Band Processing, provide the transmission service in physical layer on Radio Link.

General Base-Band Processing comprises the coding and the multiplex process of channel, and this process comprises as shown in Figure 1: CRC check, the segmentation of transmission block, chnnel coding, radio frames equilibrium, interweave for the first time, wireless frame segmentation, rate-matched, transmission channel is multiplexing, physical channel segmentation, interweave for the second time, subframe is cut apart, processing such as physical channel mapping.

Wherein, the segmentation of transmission block is divided into several sections and can be divided into groups by the channel encoder information encoded adding transmission block after the CRC check.If the transport block length after the interpolation CRC check is X, the maximum encoding block length of channel encoder is Z _Max(for example to 3GPP Turbo code, Z _Max=5114), if X＞Z _MaxThen need transmission block is cut apart.

For example, the dividing method in 3GPP Rel 6 versions is as follows:

Y＝CK-X (1)

Here C represents the code block quantity that transmission block is divided into, and K is the length of each code block, 40≤K≤Z _Max, Y is the number of filling bit.As seen this method code block of cutting apart generation has 40 to Z _MaxScope in length arbitrarily.

For the Turbo code of high-speed parallel decoding, the length of its interleaver is the multiple of degree of parallelism, and above-mentioned length continually varying transmission block segmentation method is also improper.Each code block after cutting apart all can not be needed to fill earlier " 0 " or " 1 " bit of some by Turbo encoder direct coding in each information block, and then coding.This is not the simplest and the most direct mode undoubtedly.

Summary of the invention

The technical problem to be solved in the present invention is the characteristics that take into full account the block transmission system that adopts the Turbo coding, a kind of new Turbo code piece group technology is provided, promptly judge and adopt different segmentation methods according to the transmission block size, described group technology can fully guarantee the overall performance of system and reduce the number of filling bit to greatest extent, thereby lower the complexity of Turbo decoder and reduce decoding delay.

For reaching above purpose, the invention provides a kind of segmentation method of Turbo code transmission block, described method comprises:

Judge that transport block length whether greater than the transport block length threshold value of default, if transport block length is less than or equal to the threshold value of default, then adopts interleaver sizes K _ITransmission block is carried out segmentation; If transport block length, then adopts adjacent two interleaver sizes K greater than the threshold value of default _I-1And K _ITransmission block is carried out segmentation.

Wherein, when transport block length is less than or equal to the threshold value of default, adopt described interleaver sizes KI, comprise following the transmission block segmentation method:

Here, X is the length of transmission block, Z _MaxExpression Turbo interleaver lengths table K _TableIn the longest interleaver sizes, C represents the code block number that transmission block is divided into; I represents K _TableIn the index of i interleaver sizes, 1≤i≤T, T are K _TableThe number of middle element,

K is selected in expression _TableIn more than or equal to

The interleaver sizes K of minimum _ITransmission block is carried out segmentation, and final, it is K that the transmission block of length X is divided into the C segment length _IInformation block.

Wherein, transport block length is during greater than the threshold value of default, described adjacent two interleaver sizes K _I-1And K _ITo the method for transmission block segmentation, described method comprises:

C _I＝C-C _I-1

Here X is the length of transmission block, Z _MaxExpression Turbo interleaver lengths table K _TableIn the longest interleaver sizes, C represents the code block number that transmission block is divided into; I is Turbo interleaver lengths table K _TableIn the index of i interleaver sizes, 1≤i≤T, T are K _TableThe number of middle element,

Expression K _TableIn more than or equal to

The interleaver sizes K of minimum _IIndex, C _I-1And C _IRepresent that respectively it is K that transmission block is divided into length _I-1And K _IGrouping number.

Wherein, described adjacent two interleaver sizes K _I-1And K _ITo the method for transmission block segmentation, described method comprises:

C _I-1＝C-C _I

Here X is the length of transmission block, Z _MaxExpression Turbo interleaver lengths table K _TableIn the longest interleaver sizes, C represents the code block number that transmission block is divided into; I is Turbo interleaver lengths table K _TableIn the index of i interleaver sizes, 1≤i≤T, T are K _TableThe number of middle element,

Expression K _TableIn more than or equal to

The interleaver sizes K of minimum _IIndex, C _I-1And C _IRepresent that respectively it is K that transmission block is divided into length _I-1And K _IGrouping number.

Wherein, the interleaver of Turbo code adopts group length interleaver discrete, that be fit to high-speed parallel decoding, and this group interleaver shows definite justice by an interleaver in system.

The present invention takes into full account the characteristics of the block transmission system that adopts the Turbo coding, a kind of new Turbo code piece group technology is proposed, new group technology is judged the segmentation method that employing is different according to the transmission block size, can under the prerequisite of the overall performance that keeps system, reduce the number of filling bit to greatest extent like this.And the quantity that reduces filling bit can reduce the decoding computation complexity, reduces the decoder power consumption, and reduces decoding delay, improves decoding speed.

Description of drawings

Fig. 1 is a general T urbo code coder structure chart;

Fig. 2 is the flow chart of Turbo encoding block method of partition of the present invention.

Embodiment

The present invention is described in detail below in conjunction with drawings and the specific embodiments.

Please refer to Fig. 2, Fig. 2 is the handling process of Turbo encoding block method of partition of the present invention.

At first, judge transport block length whether greater than the transport block length threshold value of default, wherein, the transport block length threshold value clearly defines in system, and note is made X _Threshold

(1) if the length of transmission block is less than or equal to threshold X _Threshold, then adopt a kind of interleaver sizes K _ITransmission block is carried out segmentation, and promptly transmission block only can be divided into a kind of length K _IGrouping, concrete grammar is as follows:

Here, C is the code block number that transmission block is divided into, and i is K _TableIn the index of i interleaver sizes, 1≤i≤T.

K is selected in expression _TableIn more than or equal to

The interleaver sizes K of minimum _ITransmission block is carried out segmentation.Finally, to be divided into the C segment length be K to the transmission block of length X _IInformation block.

Therefore,

Here 0≤δ＜K _I-K _I-1, and

(note K when I=1 _I-1=0).In this case, the number of the filling bit of transmission block is

$Y={\mathrm{CK}}_1-X$

When δ and C were bigger, filling bit number Y was bigger.For example, if K _TableZ _Min=40, Z _Max=5114, T=100 and hypothesis interleaver sizes are evenly distributed, and then the Zui Da bit number that fills out approximates 50 * C greatly.

These filling bits can be concentrated and be filled in the grouping, also can be evenly distributed in each grouping.

(2) if the length of transmission block greater than preset threshold X _Threshold, then adopt two adjacent interleaver sizes K _I-1And K _ITransmission block is carried out segmentation, wherein K _I-1And K _IBe K _TableIn element (note K when I=1 _I-1=0), K _I-1＜K _I, 1≤I≤T, D _I=K _I-K _I-1, represent two interleaver sizes K _I-1And K _IDifference, wherein, concrete segmentation method have following two kinds as follows:

First method: ask C earlier _I-1Ask C again _I, concrete grammar is as follows:

C _I＝C-C _I-1

Second method: ask C earlier _IAsk C again _I-1, concrete grammar is as follows:

C _I-1＝C-C _I

In above-mentioned two kinds of methods, C is the code block number that transmission block is divided into, and i is K _TableIn the index of i interleaver sizes, 1≤i≤T.

Expression K _TableIn more than or equal to The interleaver sizes K of minimum _IIndex.C _I-1And C _IRepresent that respectively it is K that transmission block is divided into length _I-1And K _IGrouping number.

Though the starting point difference that above-mentioned two kinds of methods are derived causes the fragmentation procedure difference, but two kinds of C that method draws _I-1And C _IValue is consistent.

Work as CK _I-X＜D _IThe time, second method is identical with the result that first method draws.

Work as CK _I-X＞=D _IThe time, the bit number that second method need be filled lacks than first method.In addition, no matter how many C values is, the upper bound of the filling bit number Y of each transmission block is D _I, that is: 0≤Y≤K _I-K _I-1

Therefore, if two adjacent lengths K of Turbo code _I-1And K _IThe performance of interleaver very approaching, then second method can significantly reduce in each transmission block because the quantity of the filling bit that piecemeal causes under the prerequisite that guarantees the transmission block performance.

At last, the information block of segmentation generation is given Turbo encoder encodes.

Below adopt a kind of concrete concrete instance that Turbo encoding block method of partition of the present invention is described:

The Turbo code interleaver adopts one group of " twice replaced polynomial (quadratic permutation polynomial QPP) " interleaver as shown in table 1 in the communication system, and wherein i represents the index of interleaver, K _IThe length of representing i interleaver, f1, f2 are twice replaced polynomial f (x)=f2*x ²The coefficient of+f1*x.To the Z that should show _Min=40, Z _Max=6114, T=188.The transport block length threshold X that communication system is set _Threshold=8192.

Table 1 twice replaced polynomial (QPP) interleaver table

According to transmission block segmentation method of the present invention, if transport block length X=8000, then X＜X _Threshold, therefore adopt a kind of interleaver sizes K _ITransmission block is carried out segmentation, and concrete grammar is as follows:

In this method option table more than or equal to

The interleaver sizes K of minimum ₁₅₅=4032 pairs of transmission blocks carry out segmentation.Be that length is that to be divided into 2 segment length be 4032 information block for 8000 transmission block.

If the length X of transmission block=12300, then X＞X _Threshold, then adopt two adjacent interleaver sizes K _I-1And K _ITransmission block is carried out segmentation, and concrete segmentation method is as follows:

C ₁₅₇＝3-C ₁₅₆＝1

Perhaps

C ₁₅₆＝C-C ₁₅₇＝2

Here C _I-1And C _IRepresent that respectively it is K that transmission block is divided into length ₁₅₆=4096 and K ₁₅₇=4160 grouping number.As seen the result of two kinds of methods is consistent.

At last, the information block behind the piecemeal is given the Turbo encoder and is encoded.

In a word, the present invention has taken into full account the characteristics of the block transmission system that adopts the Turbo coding, the fast method of partition of a kind of new transmission is proposed, this method can cooperate the Turbo code of only supporting the discrete code collection better, as adopt the Turbo code of twice replaced polynomial (QPP), the overall performance that can keep block transmission system, and reduce the filling bit number that piecemeal causes to greatest extent.

Claims (5)

1, a kind of segmentation method of Turbo code transmission block, described method comprises:

Judge that transport block length whether greater than the transport block length threshold value of default, if transport block length is less than or equal to the threshold value of default, then adopts interleaver sizes K _ITransmission block is carried out segmentation; If transport block length, then adopts adjacent two interleaver sizes K greater than the threshold value of default _I-1And K _ITransmission block is carried out segmentation.

2, method according to claim 1 is characterized in that: when transport block length is less than or equal to the threshold value of default, adopt described interleaver sizes K _ITo the transmission block segmentation method, comprise following:

Here, X is the length of transmission block, Z _MaxExpression Turbo interleaver lengths table K _TableIn the longest interleaver sizes, C represents the code block number that transmission block is divided into; I represents K _TableIn the index of i interleaver sizes, 1≤i≤T, T are K _TableThe number of middle element,

K is selected in expression _TableIn more than or equal to

The interleaver sizes K of minimum _ITransmission block is carried out segmentation, and final, it is K that the transmission block of length X is divided into the C segment length _IInformation block.

3, method according to claim 1 is characterized in that: transport block length adopts described adjacent two interleaver sizes K during greater than the threshold value of default _I-1And K _ITo transmitting the method for the segmentation of determining, described method comprises:

C _I＝C-C _I-1

Here, X is the length of transmission block, Z _MaxExpression Turbo interleaver lengths table K _TableIn the longest interleaver sizes, C represents the code block number that transmission block is divided into; I is Turbo interleaver lengths table K _TableIn the index of i interleaver sizes, 1≤i≤T, T are K _TableThe number of middle element,

Expression K _TableIn more than or equal to

The interleaver sizes K of minimum _IIndex, C _I-1And C _IRepresent that respectively it is K that transmission block is divided into length _I-1And K _IGrouping number.

4, method according to claim 1 is characterized in that: described adjacent two interleaver sizes K _I-1And K _ITo the method for transmission block segmentation, described method comprises:

C _I-1＝C-C ₁

Here, X is the length of transmission block, Z _MaxExpression Turbo interleaver lengths table K _TableIn the longest interleaver sizes, C represents the code block number that transmission block is divided into; I is Turbo interleaver lengths table K _TableIn the index of i interleaver sizes, 1≤i≤T, T are K _TableThe number of middle element,

Expression K _TableIn more than or equal to

The interleaver sizes K of minimum _IIndex, C _I-1And C _IRepresent that respectively it is K that transmission block is divided into length _I-1And K _IGrouping number.

5, method according to claim 1 is characterized in that: the interleaver of Turbo code adopts group length interleaver discrete, that be fit to high-speed parallel decoding, and this group interleaver shows definite justice by an interleaver in system.

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