CN100499448C - Low density odd-even check coding control method, system and terminal device - Google Patents

Abstract

This low density odd-even check coding control method, system and terminal device are used to solve how to raise the system throughput in the existed self-adapting control mode based on the low density odd-even check coding. This technique scheme considers fully that the decoding of LDPC is an iterative decoding, where there is a max iterative number. When the channel situation is good, only a few iterative number is enough to do decoding well. Thus some properly punching on the good channel can still keep the correct decoding with the iterative number less than the max value. Thus system throughput and frequency spectrum utilization are raised. This scheme considers that the LDPC feature of different code ratio is much different. Under the situation of punching and wrong decoding, the decoding correctness can be raised via retransmission of a few punched out data.

Description

Low density odd-even check coding control method, system and terminal equipment

Technical field

The present invention relates to data communication technology, particularly a kind of low density odd-even check coding control method, system and terminal equipment.

Background technology

Along with the fast development of present mobile communication technology, more and more higher to the requirement of system spectrum utilance, this just needs system to realize high as far as possible spectrum efficiency in limited frequency resource.AMC (Adaptive Modulation Coding, adaptive coding and modulating) technology can be according to the situation of fading channel, code rate and modulation system by regulating system, thereby under the good situation of channel condition, adopt high order modulation and high-rate coded mode with the very high availability of frequency spectrum of acquisition, and under the situation of bad channel conditions, adopt low-order-modulated and low rate coding mode to guarantee communication quality.This adaptivity that this technology had has improved the capacity and the availability of frequency spectrum of wireless communication system greatly.

LDPC (Low Density Parity Check, low-density checksum) is a kind of error correcting code of rising in recent years, and it can bring the performance better than Turbo code, and has become present many systems alternative of (comprising 802.16 systems).Because the complexity of its decoding reduces greatly, therefore can carry out iterative decoding of more times number and improve performance.Because the LDPC sign indicating number is a kind of linear block codes, can whether know correct decoding by check matrix after the decoding.The premium properties of LDPC and multifrequency nature make that its application is more and more wider.

At present similar with traditional AMC technology based on the AMC technology of LDPC sign indicating number, be that AMC and LDPC coding independently carries out, at first determine suitable MCS (ModulationCoding Scheme, modulation coding mode), adopt the LDPC of selected code check to encode then according to channel condition.Though can bring bigger performance improvement than the system of fixed modulation mode and code rate, inabundant advantage in conjunction with the LDPC sign indicating number further improves the availability of frequency spectrum.

Summary of the invention

The invention provides a kind of low density odd-even check coding control method, system and terminal equipment, in order to solve the problem that how to improve throughput of system in the existing adaptive control mode based on the low-density checksum coding realization.

For solving the problems of the technologies described above, the invention provides following technical scheme:

A kind of low density odd-even check coding control method comprises the steps:

The decoding iterations of the adaptive block that decoding is correct in the previous frame low-density checksum coding data under the statistics same-code modulation system; Adjust the punching rate of this adaptive block in the adjacent next frame low-density checksum coding data according to described decoding iterations, wherein: under each code modulation mode, 0 between the maximum iteration time decoding iterations of adaptive block being divided into several scopes, and for each scope is provided with the punching rate of appropriate level, the punching rate of the high more corresponding level of decoding iterations is low more; And the concrete method of adjustment of described adaptive block punching rate comprises:

When transfer of data begins or after retransmitting generation, start initial phase, the punching rate of the described adaptive block that comprises in the first frame low-density checksum coding data after this initial phase begins is set at 0, when reaching the setting number first, finishes the sum of continuous this adaptive block of correct decoding initial phase then, according to the average decoding iterations of the correct adaptive block of all decodings or the residing scope of decoding iterations of last adaptive block wherein, determine that initial phase finishes the punching rate rank of this adaptive block correspondence of comprising in the first frame low-density checksum coding data of back; In the transmission course of follow-up maintenance same-code modulation system, if surpassing, the decoding iterations of the adaptive block that decoding is correct in the previous frame low-density checksum coding data sets the thresholding number of times, then the punching rate of this adaptive block in the next frame coded data is turned down a rank, wherein:, then start initial phase if the current punching rate of this adaptive block is minimum rank; Otherwise then the punching rate of this adaptive block in the next frame coded data is heightened a rank, wherein:, then keep this highest level punching rate if the current punching rate of this adaptive block is a highest level.

Also comprise in the described method: if described adaptive block coding mistake then retransmits the redundant bit of being struck off in this adaptive block.

Also comprise in the described method: the channel status that begins the correspondence of the described adaptive block in back according to initial phase is determined the code modulation mode that this adaptive block uses in initial phase; In the subsequent transmission process after initial phase finishes, determine the code modulation mode of this adaptive block in the adjacent next frame low-density checksum coding data according to the channel conditions of adaptive block in the previous frame low-density checksum coding data.

In the described method: transmitting terminal is respectively according to each adaptive block corresponding codes modulation system and punching rate of comprising in each frame data, source bits encoded, punches and modulate the back generates corresponding adaptive block, and all adaptive blocks are formed Frames sends to receiving terminal; Receiving terminal carries out each adaptive block demodulation, separates punching and decoding back reduction source bits according to each adaptive block corresponding codes modulation system and punching rate of comprising in each frame data.

Preferable, described setting number is 1; And/or described setting thresholding number of times is less than maximum iteration time.

The present invention also provides a kind of low-density checksum coding control system, comprises the transmitting terminal and the receiving terminal of low-density checksum coding data, and wherein, described receiving terminal comprises:

Statistical module, the decoding iterations of the adaptive block that decoding is correct in the previous frame low-density checksum coding data under the statistics same-code modulation system;

Memory module, under each code modulation mode of corresponding stored, the appropriate level punching rate that each scope that marks off for the decoding iterations is provided with, the punching rate of the high more corresponding level of decoding iterations is low more;

First adjusting module, connect described memory module, adjust the punching rate of this adaptive block in the adjacent next frame low-density checksum coding data according to described decoding iterations, wherein: when transfer of data begins or after retransmitting generation, start initial phase, the punching rate of the described adaptive block that comprises in the first frame low-density checksum coding data after this initial phase begins is set at 0, when reaching the setting number first, finishes the sum of continuous this adaptive block of correct decoding initial phase then, according to the average decoding iterations of the correct adaptive block of all decodings or the residing scope of decoding iterations of last adaptive block wherein, determine that initial phase finishes the punching rate rank of this adaptive block correspondence of comprising in the first frame low-density checksum coding data of back; In the transmission course of follow-up maintenance same-code modulation system, if surpassing, the decoding iterations of the adaptive block that decoding is correct in the previous frame low-density checksum coding data sets the thresholding number of times, then the punching rate of this adaptive block in the next frame coded data is turned down a rank, wherein:, then start initial phase if the current punching rate of this adaptive block is minimum rank; Otherwise then the punching rate of this adaptive block in the next frame coded data is heightened a rank, wherein:, then keep this highest level punching rate if the current punching rate of this adaptive block is a highest level.

Described receiving terminal also comprises: second adjusting module, and the channel status that begins the correspondence of the described adaptive block in back according to initial phase is determined the code modulation mode that this adaptive block uses in initial phase; In the subsequent transmission process after initial phase finishes, determine the code modulation mode of this adaptive block in the adjacent next frame low-density checksum coding data according to the channel conditions of adaptive block in the previous frame low-density checksum coding data; And code modulation mode is adjusted the result send to described first adjusting module; The feedback information sending module connects described first adjusting module and second adjusting module respectively, code modulation mode is adjusted the result and the punching rate adjustment information feeds back to transmitting terminal.

Described transmitting terminal also comprises: feedback information receiver module and Frame sending module, the code modulation mode of receiving terminal feedback is adjusted the result to described feedback information receiver module and the punching rate adjustment information sends to the Frame sending module, this Frame sending module is respectively according to each adaptive block corresponding codes modulation system and punching rate of comprising in each frame data, source bits encoded, punches and modulate the back generates corresponding adaptive block, and all adaptive blocks are formed Frames sends to receiving terminal;

Described receiving terminal also comprises: the Frame receiver module, according to each adaptive block corresponding codes modulation system and punching rate of comprising in each frame data, carry out each adaptive block demodulation, separate punching and decoding back reduction source bits.

The present invention provides the terminal equipment as above-mentioned transmitting terminal and receiving terminal simultaneously.

Beneficial effect of the present invention is as follows: the decoding that technical solution of the present invention fully takes into account LDPC is iterative decoding, therefore there is maximum iteration time, when channel conditions is good, only need just can decipher correctly with less iteration, therefore carry out suitable punching for the good situation of channel conditions, can guarantee in being lower than the decode procedure of maximum iteration time that decoding is correct, and improve the throughput of system simultaneously, improve the availability of frequency spectrum; Technical solution of the present invention further utilizes the LDPC performance of different code checks to differ bigger, and under the situation of punching and decoding error, the data seldom by re-transmission is struck off have improved the decoding correctness.

Description of drawings

Fig. 1 is the main schematic flow sheet of low density odd-even check coding control method of the present invention;

Fig. 2 is the BER simulation performance schematic diagrames of three kinds of alternative MCS under AWGN;

Fig. 3 is the primary structure schematic diagram of low-density checksum coding control system of the present invention;

The throughput performance of Fig. 4 invention technical scheme and conventional AMC scheme is schematic diagram relatively.

Embodiment

The decoding of LDPC is iterative decoding, therefore there is maximum iteration time, when channel conditions is good, only need just can decipher correctly with less iteration, therefore if carry out suitable punching for the good situation of channel conditions, can guarantee in being lower than the decode procedure of maximum iteration time that then decoding is correct, and improve the throughput of system simultaneously.Utilize the LDPC performance of different code checks to differ bigger, under the situation of punching and decoding error, by the data seldom that re-transmission is struck off, just can bigger raising decoding correctness.The present invention is fully in conjunction with the above-mentioned characteristic of LDPC, for reaching the higher availability of frequency spectrum, propose a kind of method of carrying out low-density checksum coding control according to LDPC decoding iterations self adaptation, hereinafter referred to as the LDPC-AMC method, the technical conceive of this method comprises the following aspects:

1, the decoding iterations of the adaptive block that decoding is correct in the previous frame low-density checksum coding data under the statistics same-code modulation system; Adjust the punching rate of this adaptive block in the adjacent next frame low-density checksum coding data then according to the decoding iterations;

If 2 adaptive block coding mistakes then retransmit the redundant bit of being struck off in this adaptive block;

3, under each code modulation mode, 0 between the maximum iteration time decoding iterations of adaptive block being divided into several scopes, and for each scope is provided with the punching rate of appropriate level, the punching rate of the high more corresponding level of decoding iterations is low more; Like this, the concrete method of adjustment of the punching rate of adaptive block can be:

When transfer of data begins or after retransmitting generation, start initial phase, the punching rate of the adaptive block that comprises in the first frame low-density checksum coding data after this initial phase begins is set at 0, when reaching the setting number first, finishes the sum of continuous this adaptive block of correct decoding initial phase then, according to the average decoding iterations of the correct adaptive block of all decodings or the residing scope of decoding iterations of last adaptive block wherein, determine that initial phase finishes the punching rate rank of this adaptive block correspondence of comprising in the first frame low-density checksum coding data of back;

In the transmission course of follow-up maintenance same-code modulation system, if surpassing, the decoding iterations of the adaptive block that decoding is correct in the previous frame low-density checksum coding data sets the thresholding number of times, then the punching rate of this adaptive block in the next frame coded data is turned down a rank, wherein:, then start initial phase if the current punching rate of this adaptive block is minimum rank; Otherwise then the punching rate of this adaptive block in the next frame coded data is heightened a rank, wherein:, then keep this highest level punching rate if the current punching rate of this adaptive block is a highest level;

4, the channel status of correspondence that begins the back adaptive block according to initial phase is determined the code modulation mode that this adaptive block uses in initial phase; In the subsequent transmission process after initial phase finishes, determine the code modulation mode of this adaptive block in the adjacent next frame low-density checksum coding data according to the channel conditions of adaptive block in the previous frame low-density checksum coding data.

Behind the correct adaptive block of decoding, channel status according to this adaptive block determines whether to change code modulation mode earlier, if then carry out initial phase, otherwise determine whether to adjust the punching rate of corresponding adaptive block in the adjacent next frame according to the decoding iterations of this adaptive block.

According to above-mentioned technical conceive, transmitting terminal is respectively according to each adaptive block corresponding codes modulation system and punching rate of comprising in each frame data, source bits encoded, punches and modulate the back generates corresponding adaptive block, and all adaptive blocks are formed Frames sends to receiving terminal; Receiving terminal carries out each adaptive block demodulation, separates punching and decoding back reduction source bits according to each adaptive block corresponding codes modulation system and punching rate of comprising in each frame data.

Further specify above-mentioned technical conceive below in conjunction with accompanying drawing, consider a LDPC-AMC system, total K adaptive block in the frame, each adaptive block comprises M modulated unit.

If i (i=1,2 ..., K) j in the individual adaptive block (j=1,2 ..., M) modulated signal of individual unit transmission is S _{I, j}, its average power is P _s, receiving terminal AWGN noise variance is σ ², S _{I, j}The channel fading that is subjected to is H _{I, j}S _{I, j}Through the decline of channel and to be superimposed with the signal that AWGN (Adding White Gaussian Noise, additive white Gaussian noise) receives at receiving terminal afterwards be R _{I, j}That is:

R _i，j＝S _i，j×H _i，j+N _i，j

Wherein, N _{I, j}Expression AWGN, E (| N _{I, j}| ²)=σ ²

Suppose always to have the alternative MCS of T kind, be numbered MCS respectively ₁, MCS ₂..., MCS _T, and t (1≤t＜T) plants the throughput of the throughput of MCS less than t+1 kind MCS.If Modulation and Coding Scheme MCS _tCorresponding modulation system is Mod _t, code rate is Rate _t, based on code rate Rate _tThe punching scheme L is arranged _tKind, punching rate is respectively Punc _{T, 1}, Punc _{T, 2}..., Punc _{T, L}, Punc wherein _{T, l}＜Punc _{T, l+1}(l=1,2 ..., L _t-1), Punc _{T, 1}=0 expression is not punched, and system is according to decoding iterations decision punching rate, punching rate scheme Punc _{T, l}And Punc _{T, l+1}(l=1,2 ..., decoding iterations handoff threshold Lt-1) is U _{T, l}(U _{T, l}U _{T, l+1}), the maximum iteration time of LDPC is U _Max

As shown in Figure 1, describe at one of them adaptive block below, all adaptive blocks carry out same operation.Design PuncFlag is the punching flag bit.One variable W is set selects the correct decoding number of times of adaptive block down, and maximum correct decoding number of times W is set for fine tuning to be recorded in identical MCS ₀, initialization W=0.

One, initial phase

PuncFlag=0 at first carries out coarse adjustment to Modulation and Coding Scheme, determines that according to the channel fade condition of this adaptive block the preliminary MCS that adopts of this adaptive block is MCS _t, when channel situation satisfies condition t, select t kind MCS, that is:

${\mathrm{MCS}}_t=\left\{\begin{array}{c}{\mathrm{<figure-callout\; id="1"\; label="MCS"\; filenames="C200610141024E00201.png,C200610141024E00221.png"\; state="\{\{state\}\}">MCS</figure-callout>}}_1,{\mathrm{<figure-callout\; id="1"\; label="case"\; filenames="C200610141024E00201.png,C200610141024E00221.png"\; state="\{\{state\}\}">case</figure-callout>}}_1\\ {\mathrm{<figure-callout\; id="2"\; label="MCS"\; filenames="C200610141024E00211.png"\; state="\{\{state\}\}">MCS</figure-callout>}}_2,{\mathrm{<figure-callout\; id="2"\; label="case"\; filenames="C200610141024E00211.png"\; state="\{\{state\}\}">case</figure-callout>}}_2\\ \&CenterDot;\&CenterDot;\&CenterDot;\\ {\mathrm{MCS}}_T,{\mathrm{case}}_T\end{array}\right.$

Wherein, case _tThe expression channel conditions satisfies condition t (for the AMC system that carries out MCS selection principle based on signal to noise ratio, case _tThe signal to noise ratio of expression adaptive block is in the situation of a certain scope, with SNR _kThe signal to noise ratio of expression adaptive block, Th _tRepresent the signal to noise ratio handoff threshold of t and t+1 kind MCS, following formula just becomes:

${\mathrm{MCS}}_t=\left\{\begin{array}{c}{\mathrm{<figure-callout\; id="1"\; label="MCS"\; filenames="C200610141024E00201.png,C200610141024E00221.png"\; state="\{\{state\}\}">MCS</figure-callout>}}_1,{\mathrm{SNR}}_k<{\mathrm{<figure-callout\; id="1"\; label="Th"\; filenames="C200610141024E00201.png,C200610141024E00221.png"\; state="\{\{state\}\}">Th</figure-callout>}}_1\\ {\mathrm{<figure-callout\; id="2"\; label="MCS"\; filenames="C200610141024E00211.png"\; state="\{\{state\}\}">MCS</figure-callout>}}_2,{\mathrm{<figure-callout\; id="1"\; label="Th"\; filenames="C200610141024E00201.png,C200610141024E00221.png"\; state="\{\{state\}\}">Th</figure-callout>}}_1\&le;{\mathrm{SNR}}_k<{\mathrm{<figure-callout\; id="2"\; label="Th"\; filenames="C200610141024E00211.png"\; state="\{\{state\}\}">Th</figure-callout>}}_2\\ \&CenterDot;\&CenterDot;\&CenterDot;\\ {\mathrm{MCS}}_T,{\mathrm{SNR}}_k\&GreaterEqual;{\mathrm{Th}}_{T-1}\end{array}\right.;$

For the system based on other MCS selection principles, case _tOther lays down a definition.

MCS _tCorresponding modulation system is Mod _t, code rate is Rate _t, MCS _tFeedback information is returned transmitting terminal, and transmitting terminal is according to this MCS _tThe source bits of this adaptive block is encoded and modulated, send after all at last adaptive block component frames; Receiving terminal is received signal, the symbol of corresponding adaptive block is taken out, according to Mod _tThis adaptive block is carried out demodulation, according to Rate _tDecipher, recover the original bit signal at last.

When W=0, if the decoding of encoding block is incorrect in this adaptive block, the W=0 that then resets, this adaptive block or retransmit to guarantee that decoding is correct or abandon these encoding block data and carry out the transmission of next frame; If decoding is correct, then W=W+1, and record LDPC correct decoding iterations U _W

As 0＜W＜W ₀The time, if the decoding of encoding block is incorrect in this adaptive block, perhaps MCS _tDifferent with previous frame, the W=0 that then resets, this adaptive block or retransmit to guarantee that decoding is correct or abandon these encoding block data and carry out the transmission of next frame; If decoding is correct and MCS _tIdentical with previous frame, then W=W+1, and record LDPC correct decoding iterations U _W

Work as W=W ₀The time Modulation and Coding Scheme carried out fine tuning.It is all W that U is set ₀The average iterations of inferior correct decoding $U=\frac{1}{{\mathrm{<figure-callout\; id="0"\; label="W"\; filenames="C200610141024E00201.png,C200610141024E00221.png"\; state="\{\{state\}\}">W</figure-callout>}}_0}\underset{W=1}{\overset{W_0}{\mathrm{\&Sigma;}}}{U}_W$ Perhaps W ₀The iterations of inferior decoding $U={\mathrm{<figure-callout\; id="0"\; label="U\; W"\; filenames="C200610141024E00201.png,C200610141024E00221.png"\; state="\{\{state\}\}">U</figure-callout>}}_{W_{}},$ And according to the punching rate Punc of U according to the employing of following formula decision next frame _{T, l}:

${\mathrm{Punc}}_{t,l}=\left\{\begin{array}{c}{\mathrm{Punc}}_{t,1}=0,U_{t,1}<U\&le;U_{\max }\\ {\mathrm{Punc}}_{t,2},U_{t,2}<U\&le;U_{t,1}\\ \&CenterDot;\&CenterDot;\&CenterDot;\\ {\mathrm{Punc}}_{t,L_t-1},U_{t,L_t-1}<U\&le;U_{t,L_t-2}\\ {\mathrm{Punc}}_{t,L_t},U\&le;U_{t,L_t-1}\end{array}\right.$

Work as Punc _{T, l}Entered the punching stage at ≠ 0 o'clock, Punc _{T, l}Feedback information is returned transmitting terminal, and PuncFlag=1 is set, otherwise this adaptive block still is in the transmission that initial phase carries out next frame.

Two, the punching stage

Transmitting terminal is according to Rate _tEncode, according to Punc _{T, l}Punching also exists a redundant bit of destroying in the buffer memory, and according to Mod _tModulate, form adaptive block, and send with other adaptive blocks formation frames.Receiving terminal is received signal, the symbol of corresponding adaptive block is taken out, according to Mod _tThis adaptive block is carried out demodulation and demodulation result is stored in the buffer memory, according to Punc _{T, l}Separate punching, and according to Rate _tDecipher.

If the LDPC decoding error, then entering the re-transmission stage carries out the transmission of next frame;

If LDPC decoding is correct, illustrate that then channel conditions is good, judge that at first whether current channel situation satisfies the condition that t+1 kind MCS selects, and when channel situation satisfies the condition of t+1 kind MCS selection, then selects t+1 kind MCS to enter the transmission that initial phase carries out next frame.When channel situation does not satisfy the condition of t+1 kind MCS selection, then write down the iterations U ' of correct decoding process.One depression of order thresholding U is set _Down, if U '≤U _Down, then continue to keep the punching stage, and parameter constant; If U '〉U _Down, then explanation decoding iterations is near maximum iteration time, as l〉and 1 the time, the renewal punching rate is Punc _{T, l-1}, remain in the punching stage; When l=1, enter initial phase.

Three, the re-transmission stage

Receiving terminal feeds back to transmitting terminal with retransmission instructions, and transmitting terminal is being stored in redundant bit in the buffer memory according to Mod _tModulate, form adaptive block, and send with other adaptive blocks formation frames.Receiving terminal is received signal, the symbol of corresponding adaptive block is taken out, according to Mod _tThis adaptive block is carried out demodulation, the demodulation result in the previous frame is taken out from buffer memory, decipher once more with the demodulation result merging of this frame.System enters the transmission that initial phase carries out next frame.

Describe in detail once more with a specific embodiment, the ofdm system parameter of LDPC-AMC is as shown in table 1:

The relevant parameter of table 1 AMC-OFDM system

Carrier frequency	2.5GHz
		Bandwidth	10MHz
Subcarrier spacing	11.16kHz

Useful sub-carrier number	840
		FFT length	1024
CP length	64(5.6us)
		The OFDM symbol lengths	95.236us
Sample rate	11.424MHz

A frame of this Adaptable System comprises 20 OFDM symbols, according to channel relevancy per 15 adjacent sub-carriers are divided into a subband, then obtain 56 subbands, stipulate that an adaptive block comprises 15 subcarriers in 20 OFDM symbols, adopts a kind of MCS at each adaptive block.In this AMC system, initial alternative MCS (not punching) always has 3 kinds, three kinds of corresponding respectively three kinds of female sign indicating numbers of code check, each female sign indicating number can be realized various code rate by punching, thereby obtain different efficiencies of transmission, as shown in table 2, listed parameter is determined by experience.This system adopts ideal communication channel to estimate, the maximum iteration time of LDPC decoding is 50 times.

The alternative Modulation and Coding Scheme of table 2

By calculating the signal to noise ratio snr of k adaptive block _k, select preliminary MCS according to following formula:

${\mathrm{MCS}}_t=\left\{\begin{array}{c}{\mathrm{<figure-callout\; id="1"\; label="MCS"\; filenames="C200610141024E00201.png,C200610141024E00221.png"\; state="\{\{state\}\}">MCS</figure-callout>}}_1,{\mathrm{SNR}}_k<10\\ {\mathrm{<figure-callout\; id="2"\; label="MCS"\; filenames="C200610141024E00211.png"\; state="\{\{state\}\}">\; <figure-callout\; id="10"\; label="MCS"\; filenames="C200610141024E00211.png,C200610141024E00221.png"\; state="\{\{state\}\}">MCS</figure-callout>\; </figure-callout>}}_2,10\&le;{\mathrm{SNR}}_k<16.7\\ {\mathrm{<figure-callout\; id="3"\; label="MCS"\; filenames="C200610141024E00211.png"\; state="\{\{state\}\}">MCS</figure-callout>}}_3,{\mathrm{SNR}}_k\&GreaterEqual;16.7\end{array}\right.---\left(10\right)$

Parameter in the formula (1) is to obtain by the bit error rate BER performance simulation of all MCS under AWGN, simulation result as shown in Figure 2, wherein, curve 201 is for code modulation mode is 1/2, the simulation result of QPSK, curve 202 is for code modulation mode is 2/3, the simulation result of 16QAM, curve 203 is for code modulation mode is 3/4, the simulation result of 64QAM, and the standard that threshold value is determined is to make the BER of scheme performance keep below 10 ^-3Principle.

One, initial phase

At first Modulation and Coding Scheme is carried out coarse adjustment, select MCS according to channel conditions _tBe preliminary Modulation and Coding Scheme, the corresponding modulating mode is Mod _t, code rate is Rate _t, MCS _tFeedback information is returned transmitting terminal, and transmitting terminal is according to Rate _tSource bits to this adaptive block is encoded, according to Mod _tModulate, send after all at last adaptive block component frames; Receiving terminal is received signal, and the symbol of corresponding adaptive block is taken out, and separates accordingly to be in harmonious proportion and deciphers, and recovers the original bit signal at last.

In this example, can maximum correct decoding number of times W be set for fine tuning ₀=1.If the decoding of encoding block is incorrect in this adaptive block, then abandon the data of this adaptive block, carry out the transmission of next frame; If decoding is correct, the LDPC iterations of supposing the correct decoding process is U, and system carries out according to table 2 according to the punching rate that U decision present frame adopts.Work as Punc _{T, l}Entered the punching stage at ≠ 0 o'clock, Punc _{T, l}Feed back to transmitting terminal, PuncFlag=1, otherwise adaptive block still is in initial phase.

Two, the punching stage

Transmitting terminal is according to Rate _tEncode, according to Punc _{T, l}Punching also exists a redundant bit of destroying in the buffer memory, and according to Mod _tModulate, form adaptive block, and send with other adaptive blocks formation frames.Receiving terminal is received signal, the symbol of corresponding adaptive block is taken out, according to Mod _tThis adaptive block is carried out demodulation and demodulation result is stored in the buffer memory, according to Punc _{T, l}Separate punching, and according to Rate _tDecipher, recover the original bit signal at last, according to decode results:

1,, guarantees the decoding correctness by retransmitting if the LDPC decoding error then enters the re-transmission stage;

2,, judge at first that then whether current channel situation satisfies the condition that t+1 kind MCS selects, and promptly judges SNR if LDPC decoding is correct _kWhether satisfy the condition that t+1 kind MCS selects in (1) formula, when channel situation satisfies, then select t+1 kind MCS to enter the transmission that initial phase carries out next frame.When channel situation does not satisfy, then write down the iterations U ' of correct decoding process.One depression of order thresholding U is set _Down=45, then:

If U '≤45 then continue to keep the punching stage, and parameter constant;

If U '〉45, then explanation decoding iterations is near maximum iteration time, as l〉1 the time, the renewal punching rate is Punc _{T, l-1}, remain in the punching stage; When l=1, enter initial phase and reselect MCS.

Three, the re-transmission stage

Retransmission instructions is fed back to transmitting terminal, and transmitting terminal is being stored in redundant bit in the buffer memory according to Mod _tModulate, form adaptive block, and send with other adaptive blocks formation frames.Receiving terminal is received signal, the symbol of corresponding adaptive block is taken out, according to Mod _tThis adaptive block is carried out demodulation, the demodulation result in the previous frame is taken out from buffer memory, decipher once more with the demodulation result merging of this frame.

System enters initial phase, carries out the transmission of next frame.

As shown in Figure 3, a kind of low-density checksum coding control system of realization technical solution of the present invention comprises: the transmitting terminal 301 of low-density checksum coding data and receiving terminal 302;

Wherein, receiving terminal 302 comprises:

Statistical module 3021, the decoding iterations of the adaptive block that decoding is correct in the previous frame low-density checksum coding data under the statistics same-code modulation system;

First adjusting module 3022 is adjusted the punching rate of this adaptive block in the adjacent next frame low-density checksum coding data according to deciphering iterations;

Memory module 3023 connects first adjusting module 3022, under each code modulation mode of corresponding stored, and the appropriate level punching rate that each scope that marks off for the decoding iterations is provided with, the punching rate of the high more corresponding level of decoding iterations is low more;

The concrete grammar that first adjusting module 3022 is adjusted the adaptive block punching rate comprises:

When transfer of data begins or after retransmitting generation, start initial phase, the punching rate of the adaptive block that comprises in the first frame low-density checksum coding data after this initial phase begins is set at 0, when reaching the setting number first, finishes the sum of continuous this adaptive block of correct decoding initial phase then, according to the average decoding iterations of the correct adaptive block of all decodings or the residing scope of decoding iterations of last adaptive block wherein, determine that initial phase finishes the punching rate rank of this adaptive block correspondence of comprising in the first frame low-density checksum coding data of back;

In the transmission course of follow-up maintenance same-code modulation system, if surpassing, the decoding iterations of the adaptive block that decoding is correct in the previous frame low-density checksum coding data sets the thresholding number of times, then the punching rate of this adaptive block in the next frame coded data is turned down a rank, wherein:, then start initial phase if the current punching rate of this adaptive block is minimum rank; Otherwise then the punching rate of this adaptive block in the next frame coded data is heightened a rank, wherein:, then keep this highest level punching rate if the current punching rate of this adaptive block is a highest level.

Second adjusting module 3024, the channel status that begins the correspondence of back adaptive block according to initial phase is determined the code modulation mode that this adaptive block uses in initial phase; In the subsequent transmission process after initial phase finishes, determine the code modulation mode of this adaptive block in the adjacent next frame low-density checksum coding data according to the channel conditions of adaptive block in the previous frame low-density checksum coding data; And code modulation mode is adjusted the result send to first adjusting module, 3023, the first adjusting modules 3023 when code modulation mode changes, restart initial phase;

Feedback information sending module 3025 connects first adjusting module 3023 and second adjusting module 3024 respectively, code modulation mode is adjusted the result and the punching rate adjustment information feeds back to transmitting terminal 301;

Frame receiver module 3026 according to each adaptive block corresponding codes modulation system and punching rate of comprising in each frame data, carries out each adaptive block demodulation, separates punching and decoding back reduction source bits.

Each adaptive block corresponding codes modulation system that Frame receiver module 3026 uses and punching rate can be transmitted by feedback information sending module 3025, as shown in Figure 3, also can directly be sent by first adjusting module 3022 and second adjusting module 3024.

Transmitting terminal 301 comprises:

Feedback information receiver module 3011 and Frame sending module 3012, the code modulation mode of receiving terminal feedback is adjusted the result to feedback information receiver module 3011 and the punching rate adjustment information sends to Frame sending module 3012, this Frame sending module 3012 is respectively according to each adaptive block corresponding codes modulation system and punching rate of comprising in each frame data, source bits encoded, punches and modulate the back generates corresponding adaptive block, and all adaptive blocks are formed Frames sends to receiving terminal.

The concrete processing details of said system no longer repeats here referring to describing in the method.

Technical solution of the present invention compared with prior art throughput simulation result as shown in Figure 4, comprising:

1, only adopts the conventional AMC throughput of system result of three kinds of MCS, shown in curve 401;

2, adopted the throughput result of the conventional AMC system with the totally 8 kind MCSs of trimming scheme in being also included within as shown in table 2, shown in curve 402;

3, adopt the throughput result of invention technical scheme, shown in curve 403, the statistical method of this throughput is based on the encoding block of correct decoding, and presentation of results the present invention can improve throughput of system greatly.

Consider that for signaling consumption in the specific embodiment of the invention, the transmission of signaling is undertaken by special signaling channel, and the transmission of signaling hypothesis is errorless.Three kinds of AMC schemes in the comparison diagram, the signaling consumption of every kind of AMC scheme is basic identical, and therefore for the lifting of the throughput shown in the figure, signaling consumption is all ignored.

Obviously, those skilled in the art can carry out various changes and modification to the present invention and not break away from the spirit and scope of the present invention.Like this, if of the present invention these are revised and modification belongs within the scope of claim of the present invention and equivalent technologies thereof, then the present invention also is intended to comprise these changes and modification interior.

Claims (11)

1, a kind of low density odd-even check coding control method is characterized in that, comprises the steps:

The decoding iterations of the adaptive block that decoding is correct in the previous frame low-density checksum coding data under the statistics same-code modulation system;

Adjust the punching rate of this adaptive block in the adjacent next frame low-density checksum coding data according to described decoding iterations, wherein: under each code modulation mode, 0 between the maximum iteration time decoding iterations of adaptive block being divided into several scopes, and for each scope is provided with the punching rate of appropriate level, the punching rate of the high more corresponding level of decoding iterations is low more; And the concrete method of adjustment of described adaptive block punching rate comprises:

When transfer of data begins or after retransmitting generation, start initial phase, the punching rate of the described adaptive block that comprises in the first frame low-density checksum coding data after this initial phase begins is set at 0, when reaching the setting number first, finishes the sum of continuous this adaptive block of correct decoding initial phase then, according to the average decoding iterations of the correct adaptive block of all decodings or the residing scope of decoding iterations of last adaptive block wherein, determine that initial phase finishes the punching rate rank of this adaptive block correspondence of comprising in the first frame low-density checksum coding data of back; In the transmission course of follow-up maintenance same-code modulation system, if surpassing, the decoding iterations of the adaptive block that decoding is correct in the previous frame low-density checksum coding data sets the thresholding number of times, then the punching rate of this adaptive block in the next frame coded data is turned down a rank, wherein:, then start initial phase if the current punching rate of this adaptive block is minimum rank; Otherwise then the punching rate of this adaptive block in the next frame coded data is heightened a rank, wherein:, then keep this highest level punching rate if the current punching rate of this adaptive block is a highest level.

2, the method for claim 1 is characterized in that, also comprises in the described method: if described adaptive block coding mistake then retransmits the redundant bit of being struck off in this adaptive block.

3, method as claimed in claim 2 is characterized in that, also comprises in the described method:

The channel status that begins the correspondence of the described adaptive block in back according to initial phase is determined the code modulation mode that this adaptive block uses in initial phase;

In the subsequent transmission process after initial phase finishes, determine the code modulation mode of this adaptive block in the adjacent next frame low-density checksum coding data according to the channel conditions of adaptive block in the previous frame low-density checksum coding data.

4, method as claimed in claim 3 is characterized in that, in the described method:

Transmitting terminal is respectively according to each adaptive block corresponding codes modulation system and punching rate of comprising in each frame data, source bits encoded, punches and modulate the back generates corresponding adaptive block, and all adaptive blocks are formed Frames sends to receiving terminal;

Receiving terminal carries out each adaptive block demodulation, separates punching and decoding back reduction source bits according to each adaptive block corresponding codes modulation system and punching rate of comprising in each frame data.

5, the method for claim 1 is characterized in that, described setting number is 1; And/or described setting thresholding number of times is less than maximum iteration time.

6, a kind of low-density checksum coding control system comprises the transmitting terminal and the receiving terminal of low-density checksum coding data it is characterized in that described receiving terminal comprises:

Statistical module, the decoding iterations of the adaptive block that decoding is correct in the previous frame low-density checksum coding data under the statistics same-code modulation system;

Memory module, under each code modulation mode of corresponding stored, the appropriate level punching rate that each scope that marks off for the decoding iterations is provided with, the punching rate of the high more corresponding level of decoding iterations is low more;

First adjusting module, connect described memory module, adjust the punching rate of this adaptive block in the adjacent next frame low-density checksum coding data according to described decoding iterations, wherein: when transfer of data begins or after retransmitting generation, start initial phase, the punching rate of the described adaptive block that comprises in the first frame low-density checksum coding data after this initial phase begins is set at 0, when reaching the setting number first, finishes the sum of continuous this adaptive block of correct decoding initial phase then, according to the average decoding iterations of the correct adaptive block of all decodings or the residing scope of decoding iterations of last adaptive block wherein, determine that initial phase finishes the punching rate rank of this adaptive block correspondence of comprising in the first frame low-density checksum coding data of back; In the transmission course of follow-up maintenance same-code modulation system, if surpassing, the decoding iterations of the adaptive block that decoding is correct in the previous frame low-density checksum coding data sets the thresholding number of times, then the punching rate of this adaptive block in the next frame coded data is turned down a rank, wherein:, then start initial phase if the current punching rate of this adaptive block is minimum rank; Otherwise then the punching rate of this adaptive block in the next frame coded data is heightened a rank, wherein:, then keep this highest level punching rate if the current punching rate of this adaptive block is a highest level.

7, system as claimed in claim 6 is characterized in that, described receiving terminal also comprises:

Second adjusting module, the channel status that begins the correspondence of the described adaptive block in back according to initial phase is determined the code modulation mode that this adaptive block uses in initial phase; In the subsequent transmission process after initial phase finishes, determine the code modulation mode of this adaptive block in the adjacent next frame low-density checksum coding data according to the channel conditions of adaptive block in the previous frame low-density checksum coding data; And code modulation mode is adjusted the result send to described first adjusting module, described first adjusting module restarts initial phase when code modulation mode changes;

The feedback information sending module connects described first adjusting module and second adjusting module respectively, code modulation mode is adjusted the result and the punching rate adjustment information feeds back to transmitting terminal.

8, system as claimed in claim 7 is characterized in that,

Described transmitting terminal also comprises: feedback information receiver module and Frame sending module, the code modulation mode of receiving terminal feedback is adjusted the result to described feedback information receiver module and the punching rate adjustment information sends to the Frame sending module, this Frame sending module is respectively according to each adaptive block corresponding codes modulation system and punching rate of comprising in each frame data, source bits encoded, punches and modulate the back generates corresponding adaptive block, and all adaptive blocks are formed Frames sends to receiving terminal;

Described receiving terminal also comprises: the Frame receiver module, according to each adaptive block corresponding codes modulation system and punching rate of comprising in each frame data, carry out each adaptive block demodulation, separate punching and decoding back reduction source bits.

9, a kind of terminal equipment based on low-density checksum coding comprises the feedback information sending module, it is characterized in that, described terminal equipment also comprises:

Statistical module, the decoding iterations of the adaptive block that decoding is correct in the previous frame low-density checksum coding data under the statistics same-code modulation system;

Memory module, under each code modulation mode of corresponding stored, the appropriate level punching rate that each scope that marks off for the decoding iterations is provided with, the punching rate of the high more corresponding level of decoding iterations is low more;

First adjusting module, connect described memory module, adjust the punching rate of this adaptive block in the adjacent next frame low-density checksum coding data according to described decoding iterations, and by described feedback information sending module transmission punching rate adjustment information, wherein: when transfer of data begins or after retransmitting generation, start initial phase, the punching rate of the described adaptive block that comprises in the first frame low-density checksum coding data after this initial phase begins is set at 0, when reaching the setting number first, finishes the sum of continuous this adaptive block of correct decoding initial phase then, according to the average decoding iterations of the correct adaptive block of all decodings or the residing scope of decoding iterations of last adaptive block wherein, determine that initial phase finishes the punching rate rank of this adaptive block correspondence of comprising in the first frame low-density checksum coding data of back; In the transmission course of follow-up maintenance same-code modulation system, if surpassing, the decoding iterations of the adaptive block that decoding is correct in the previous frame low-density checksum coding data sets the thresholding number of times, then the punching rate of this adaptive block in the next frame coded data is turned down a rank, wherein:, then start initial phase if the current punching rate of this adaptive block is minimum rank; Otherwise then the punching rate of this adaptive block in the next frame coded data is heightened a rank, wherein:, then keep this highest level punching rate if the current punching rate of this adaptive block is a highest level.

10, terminal equipment as claimed in claim 9 is characterized in that, described terminal equipment also comprises:

Second adjusting module, the channel status that begins the correspondence of the described adaptive block in back according to initial phase is determined the code modulation mode that this adaptive block uses in initial phase; In the subsequent transmission process after initial phase finishes, determine the code modulation mode of this adaptive block in the adjacent next frame low-density checksum coding data according to the channel conditions of adaptive block in the previous frame low-density checksum coding data, and send code modulation mode by described feedback information sending module and adjust the result; Simultaneously code modulation mode is adjusted the result and sent to described first adjusting module, described first adjusting module restarts initial phase when code modulation mode changes.

11, terminal equipment as claimed in claim 10 is characterized in that, described terminal equipment also comprises:

The Frame receiver module according to each adaptive block corresponding codes modulation system and punching rate of comprising in each frame data of receiving, carries out each adaptive block demodulation, separates punching and decoding back reduction source bits.

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