CN101807966B - Parity check code decoder and receiving system - Google Patents

Abstract

The invention relates to a parity check code decoder, which is suitable for receiving a channel quality ratio and at least N bits to be decoded. The parity check code decoder comprises a verification device, a reliability generating device, a bit exchanging device, an exchange checking device and a reliability updating device, wherein the verification device takes each bit to be decoded as a one-bit node and makes one matrix multiply an N-bit node to obtain an (N-K) checking node; the reliability generating device generates a reliable pointer, which is used as an abnormal check index transmitted to the checking node by the bit node, for each bit node; the bit exchanging device generates an abnormal bit pointer for each checking node so as to transmit to the bit node; the exchange checking device updates a plurality of abnormal check pointers, which are used to be transmitted to the checking nodes by the bit nodes, based on the abnormal bit pointers; and the reliability updating device updates the reliable pointer of each bit node according to the abnormal check pointer so as to determine an updating value of each bit node.

Description

Parity check (ldpc) decoders and receiving system

Technical field

The invention relates to a kind of decoding technique, be meant a kind of low density parity check code (low-density parity-check code, LDPC) decoder and receiving system especially.

Background technology

Low density parity check code (LDPC) is a kind of error correcting code.Because coding gain approaches shannon limit (Shannon limit); Recently also be employed in some communication standards gradually; For example: second generation satellite digital video broadcast (Digital Video Broadcast-Satellite version 2; DVB-S2), digital TV ground multimedia broadcasting (Digital Terrestrial Multimedia Broadcasting, DTMB) or IEEE 802.11.In receiving terminal, the LDPC decoder is that each position to be decoded of self-channel in the future is regarded as a node (bit node), and wherein N position node must satisfy (N-K) individual condition, just can obtain correct decoding.And these conditions promptly are called inspection node (check node).

In order to reduce channel disturbance, the LDPC decoder is checked with these inspection nodes and whether is accurately received these positions to be decoded.Thereby be under zero the prerequisite satisfying these inspection nodes; Make this equipotential node and these inspection node exchange possible the probability (that is: possibly be 0 or 1 probability) of this equipotential node each other, in the hope of restoring these to be decoded that do not receive channel disturbance with iterative manner.Therefore, be called the confidence level transmission (belief propagation, BP).

But the computation complexity of iterative process is quite high, minimumly approaches with (Min-sum) algorithm so adopt.And, more revising, that is skew confidence level transmission (off set-BP) with a side-play amount for fear of therefore excessively estimating the possibility probability.Yet side-play amount can't change with the channel quality, causes this equipotential node probability of iteration gained still accurate inadequately, and the confidence level of decoding output is not good yet jointly.

And Changzheng Ma and Boon Poh Ng are in the paper (LDPC DecodingAlgorithm with Estimation of Noise Variance) that was proposed in 2006; Though also advise carrying out iterative computation next time with the channel quality after upgrading; But computational process is quite complicated, so can cause the burden on the hardware.

Summary of the invention

Therefore; The object of the invention promptly is to provide a kind of parity check (ldpc) decoders and receiving system that can reduce computation complexity and improve the decoding confidence level, adds the consideration of channel quality in iterative process; Can make this equipotential node probability have more accuracy, and help to reduce iterations.

So receiving system of the present invention is applicable to through channel to receive N modulating data through low density parity check code (LDPC) coding at least that comprise: channel estimator calculates the channel quality ratio of reacting this channel quality according to these modulating datas; And LDPC decoder; Obtain N position node at least according to these modulating datas; Comprise: demo plant is multiplied by this N position node with low-density parity check (LDPC) matrix and obtains (N-K) individual inspection node, and each inspection node passes message mutually based on this matrix and at least two position nodes; The reliability generation device is for each node produces reliable indicator, to be used as the different inspection index that this node sends the inspection node that can pass message mutually to; Exchange position device is based on this channel quality ratio and these different inspection indexs, for each inspection node produces at least two dystopy pointers, to send the position node that can pass message mutually respectively to; The switching exam device upgrades a plurality of different inspection pointers based on this isotonic pointer, supplies each node to send the inspection node that can pass message mutually respectively to; And the reliability updating device, come the reliable indicator of Refreshing Every position node according to these different inspection pointers, and then determine the updating value of each node.

And parity check (ldpc) decoders of the present invention; Be applicable to the channel quality ratio that receives the reaction channel quality with N encode through low density parity check code (LDPC) to be decoded at least; Comprise: demo plant; Looking each position to be decoded is a node, and is multiplied by this N position node with low-density parity check (LDPC) matrix and obtains (N-K) individual inspection node, and each inspection node passes message mutually based on this matrix and at least two position nodes; The reliability generation device is for each node produces a reliable indicator, to be used as the different inspection index that this node sends the inspection node that can pass message mutually to; Exchange position device is based on this channel quality ratio and these different inspection indexs, for each inspection node produces at least two dystopy pointers, to send the position node that can pass message mutually respectively to; The switching exam device upgrades a plurality of different inspection pointers based on this isotonic pointer, supplies each node to send the inspection node that can pass message mutually respectively to; And the reliability updating device, come the reliable indicator of Refreshing Every position node according to these different inspection pointers, and then determine the updating value of each node.

Description of drawings

Fig. 1 is a calcspar, and the preferred embodiment of receiving system of the present invention is described;

Fig. 2 is a calcspar, and the preferred embodiment of parity check (ldpc) decoders of the present invention is described;

Fig. 3 is the calcspar of the exchange position device of this preferred embodiment;

Fig. 4 is a sketch map, the corresponding relation that the detail bit node is cautious with inspection;

Fig. 5 (a), 5 (b) and 5 (c) are sketch mapes, and the detail bit node can pass message mutually with inspection is cautious;

Fig. 6 is a flow chart, and the decoding process of LDPC decoder is described;

Fig. 7 is a flow chart, and the execution in step of exchange position device is described;

Fig. 8 is a flow chart, and the execution in step of demo plant is described;

Fig. 9 is a calcspar, and another enforcement aspect of exchange position device is described; And

Figure 10 is a calcspar, and the another enforcement aspect of exchange position device is described.

[main element label declaration]

100 receiving systems

1 low-density odd-even check code decoder

11 reliability generation devices, 128,168,178 multiplex (MUX) unit

12,16,17 exchange position device 13 switching exam devices

121 symbol decision unit, 14 reliability updating devices

122 minimum value screening unit, 15 demo plants

123 product unit, 2 reflection love darts

124,164,174 first subtrator 3 remappers

125,165, second subtrator, 5 channel estimator

126,166,176 first sections value cell 7 channels

127,167,177 second sections value cell 61～65 steps

621～624,651～654 substeps

Embodiment

About aforementioned and other technology contents, characteristics and effect of the present invention, in the following detailed description that cooperates with reference to a graphic preferred embodiment, can clearly appear.

Consult Fig. 1, the preferred embodiment of receiving system 100 of the present invention is applicable to the carrier signal that receives through the LDPC coding through channel 7, and this carrier signal has many style system data.This preferred embodiment comprises LDPC decoder 1, reflection love dart 2 (de-mapper), remapper 3 (re-mapper) and channel estimator 5.In the present embodiment; Carrier signal adopts binary phase shift keying (Binary Phase ShiftKeying; BPSK) modulation system; But also can be two-dimentional phase shift keying (Quadrature Phase ShiftKeying, QPSK), the orthogonal frequency multiplex (MUX) (Orthogonal Frequency Division Multiplex, OFDM) or other.

Channel estimator 5 calculates show channel quality first according to these modulating datas and estimates channel variance σ _STARTAnd reflection love dart 2 adopts BPSK rectification mode to judge that these modulating datas are to obtain a plurality of positions to be decoded.For example: when judging that modulating data is 1, then evaluating position to be decoded is 1; And when judging that modulating data is-1, then evaluating position to be decoded is 0.Wherein, judgment principle can adopt rigid or soft.

It is a Node B that LDPC decoder 1 is looked each position to be decoded ₀, B ₁, B ₂..., and decode according to this.And in decoding simultaneously, upgrade this equipotential Node B ₀, B ₁, B ₂... possibly be 1 or 0 probability, and then determine this equipotential Node B ₀, B ₁, B ₂... updating value.Remapper 3 upgrades position, back Node B more according to the BPSK modulation system with these ₀, B ₁, B ₂... be mapped as a plurality of mapping (enum) datas again.Then, channel estimator 5 can be calculated these mapping (enum) data is average as channel variance σ after upgrading with the error between these modulating datas again _UPDATE, and the delivery channel mass ratio $V(=\frac{{{\mathrm{\σ}}_{\mathrm{UPDATE}}}^2}{{{\mathrm{\σ}}_{\mathrm{START}}}^2})$ Supply the decoding foundation of LDPC decoder 1.

Consult Fig. 2 and Fig. 3, LDPC decoder 1 comprises reliability generation device 11, exchange position device 12, switching exam device 13, reliability updating device 14 and demo plant 15.And an exchange position device 12 has symbol decision unit 121, minimum value screening unit 122, product unit 123, first subtrator 124, second subtrator 125, first section value cell 126, second section value cell 127 and multiplex (MUX) unit 128.

And the demo plant 15 of LDPC decoder 1 is to upgrade a back Node B with matrix size for the low-density parity check (LDPC) matrix of (N-K) * N is multiplied by N ₀, B ₁, B ₂... B _N-1Obtain checking node C after (N-K) individual renewal ₀, C ₁, C ₂... C _N-K-1Upgrade back inspection node C if it should be noted that these ₀, C ₁, C ₂... C _N-K-1Be zero, then position, back Node B is upgraded in representative ₀, B ₁, B ₂... B _N-1Not disturbed by channel 7.

This matrix has (N-K) * N element (entry) (element value is 0 or 1), and (N-K)＞0.It is 1 that the m+1 of hypothesis matrix is listed as the n+1 row element, then definition inspection node C _mWith the position Node B _nCan pass message mutually, and same inspection node C _mCan pass message mutually with at least two position nodes, m=0 wherein, 1,2... (N-K-1), n=0,1,2...N-1.For instance, if matrix, this equipotential node and these inspection nodes shown in equation (1), then relationships between nodes can Fig. 4 explanation, and passes to same inspection node C ₂Message must come the self-alignment Node B ₁, B ₂, B ₄And pass to same position Node B ₄Message must come self-check node C ₂, C ₃

$\left[\begin{array}{cccccc}1& 0& 0& 1& 0& 0\\ 0& 0& 0& 1& 0& 1\\ 0& 1& 1& 0& 1& 0\\ 0& 0& 0& 0& 1& 1\end{array}\right]\·\left[\begin{array}{c}{B}_0\\ B_1\\ B_2\\ B_3\\ B_4\\ B_5\end{array}\right]=\left[\begin{array}{c}{C}_0\\ C_1\\ C_2\\ C_3\end{array}\right]---\left(1\right)$

Consult Fig. 2 and Fig. 6; In order to simplify calculating; All decoding processes of the LDPC decoder 1 of present embodiment are with logarithm similarity ratio (Log-likelihood ratio; LLR) with multiplying convert into better simply add operation (for example: Z=X * Y, get just be LLR (Z)=LLR (X)+LLR (Y) behind the LLR), and decoding step is following:

Step 61: demo plant 15 can a preset iteration metering be zero, and exchange position device 12 also can be preset the biased D of moving of one different (extrinsic).But in side circuit, also can change into based on just estimating channel variance σ _STARTProduce this dystopy skew D.

And, based on just estimating channel variance σ _START, reliability generation device 11 is the position Node B _nProduce like equation (2) first and estimate reliability index Q _{START_n}, to be used as a Node B _nSend the inspection node C that can pass message mutually to _mDifferent inspection index Q _Mn(like Fig. 5 (a)).Therefore, the confidence level of the accuracy of channel variance meeting profound influence reliability index.

$Q_{\mathrm{START}\_n}=\ln \left[\frac{\mathrm{Pr}(B_n=0)}{\mathrm{Pr}(B_n=1)}\right]=\frac{-2\sqrt{E_B}{\left|H\right|}^2\·B_n}{{{\mathrm{\σ}}_{\mathrm{START}}}^2}=Q_{\mathrm{mn}}---\left(2\right)$

Reliable indicator is meant a Node B _nMaybe for 0 probability with possibly be the ratio of 1 probability, and E _BBe each process LDPC coded data energy of place, transmission end, and | H| ²Change with modulation system and channel conditions.If the employing multi-carrier modulation, then different BPSK modulating datas the channel strength of process have difference.And present embodiment adopts single carrier, so | H| ²=1.Moreover, because reliability index is the result who gets LLR, so when the position Node B _nMaybe be higher for 0 probability, reliability index can be greater than 0.Otherwise reliability index is not more than 0.And maybe be high more for the probability of a particular value (0 or 1), the absolute value of reliability index is big more.

Step 62: exchange position device 12 produces by inspection node C _mSend the position Node B that can pass message mutually to _nA dystopy pointer R _MnIts definition is to satisfy inspection node C _mBe under zero the prerequisite, for the position node that can pass message mutually exchange each other maybe probability (that is: possibly maybe possibly be 1 probability for 0 probability) message; And exchange is meant dystopy pointer R _MnContained message only comprise from other can with inspection node C _mPass the position Node B of message mutually _{N '}And do not comprise a Node B _nItself.With Fig. 5 (b) is example, at inspection node C ₂Be that exchange position device 12 can be with the position Node B under zero the prerequisite ₁, B ₂The message of possible probability inform a Node B ₄

Quite complicated in view of the calculating that exchanges messages, so the exchange position device 12 of this preferred embodiment adopts one to simplify describing mode, and be aided with channel quality ratio V and approach dystopy pointer R _Mn, shown in equation (3).

$R_m\≈\left[\underset{n^{\′}\∈N\left(m\right)\backslash n}{\mathrm{\Π}}\mathrm{sign}\left(Q_{{\mathrm{mn}}^{\′}}\right)\right]\·\left\{\underset{n^{\′}\∈N\left(m\right)\backslash n}{\min }\right|Q_{{\mathrm{mn}}^{\′}}|-D\·V\}---\left(3\right)$

In the aforesaid equation, | x| is the absolute value of x, N (m) n the representative except the position Node B _nOuter other can with inspection node C _mPass the position Node B of message mutually _{N '},

Refer to the minimum value of G in the x set, and sgn (x) is meant the symbol (plus or minus) of x.

And step 62 comprises like the following substep of Fig. 7 and tries to achieve equation (3):

Substep 621: minimum value screening unit 122 from can with inspection node C _mPass the position node (B of message mutually _nAnd B _{N '}) different inspection index absolute value | Q _Mn|, | Q _{Mn '}| in choose reckling and be used as first set point value, and choose time little person and be used as second set point value.

Substep 622: product unit 123 multiplies each other dystopy skew D and channel quality ratio V and obtains upgrading the back skew.And first subtrator 124 makes first set point value deduct this renewal back skew and obtains first subtraction value.Then, export according to the symbol of first subtraction value by first section value cell 126 and be not less than zero first bit pointer.That is to say, when first subtraction value is not less than zero, be first bit pointer with first subtraction value; When less than zero, be first bit pointer with null value.In like manner, second subtrator 125 is also made a concerted effort to export corresponding second set point value with second section value cell 127 and is not less than zero second bit pointer.

Substep 623: symbol decision unit 121 will belong to N (m) n the position Node B _{N '}Different inspection index Q _{Mn '}Symbol (plus or minus) multiply each other and export symbol indication, then continue substep 624.And the execution sequence of this substep 623 is not limited thereto, as long as before substep 624, accomplish.

Substep 624: wherein one of first bit pointer and second bit pointer chosen in multiplex (MUX) unit 128, and it is multiplied by symbol indication of substep 623 and obtains dystopy pointer R _MnThe mode of choosing is: for inspection node C _m, when first set point value is to be selected from a Node B _nDifferent inspection index absolute value | Q _Mn|, then multiplex (MUX) unit 128 is the position Node B _nChoose second bit pointer and be used as dystopy pointer R _MnAnd be all the other relevant bits Node B _{N '}Choose first bit pointer and be used as dystopy pointer R _{Mn '}

This is because send a Node B to _nDystopy pointer R _MnThe different inspection index absolute value that does not comprise itself | Q _Mn|.So when different inspection index absolute value | Q _Mn| be the minimum value of selecting, send a Node B so to _nDystopy pointer R _MnCan only select time little person to calculate.

And step 62 and known offset confidence level are transmitted the difference of (offset-BP) and be: exchange position device 12 also is multiplied by dystopy skew D with channel quality ratio V, makes dystopy pointer R _MnCan be along with upgrading back channel variance σ _UPDATEAdjust, but the channel quality of effecting reaction estimation at present and raising decoding confidence level.And when misestimating channel variance σ _STARTSo that when adopting excessive dystopy skew D, if not in good time to upgrade back channel variance σ _UPDATEAdjust, will procrastinate decoding speed.

In addition, because exchange of the present invention position device 12 is with channel quality ratio $V(=\frac{{{\mathrm{\σ}}_{\mathrm{UPDATE}}}^2}{{{\mathrm{\σ}}_{\mathrm{START}}}^2})$ Be multiplied by dystopy skew D and come the effecting reaction channel quality, only need to calculate during iteration in the first time Be multiplied by σ afterwards again _UPDATE ²Get final product.And known way normally is multiplied by equation (2) But the σ of iteration each time _UPDATE ²All different, so must carry out division calculation again.Therefore, compared to known technology, the present invention adopts multiplication to calculate and (is multiplied by σ _UPDATE ²) realize, obviously simply many.

Step 63: switching exam device 13 upgrades by the position Node B _nSend the inspection node C that can pass message mutually to _mDifferent inspection index Q _MnIts definition is: satisfying except inspection node C _mOuter other can with the position Node B _nPass the inspection node C of message mutually _{M '}Be under zero the prerequisite, to be inspection node C _mWith C _{M '}Exchange dystopy pointer R each other _Mn, R _{M ' n}And exchange is meant different inspection index Q _MnContained message only comprise from other can with the position Node B _nPass the inspection node C of message mutually _{M '}And do not comprise inspection node C _mWith Fig. 5 (c) is example, through the position Node B ₄, switching exam device 13 can will satisfy inspection node C ₃Be that zero dystopy pointer is informed inspection node C ₂

This different inspection index Q _MnShown in equation (4), wherein M (n) m representative except inspection node C _mOuter other can with the position Node B _nPass the inspection node C of message mutually _{M '}

$Q_{\mathrm{mn}}=Q_{\mathrm{START}\_n}+\underset{m^{\′}\∈M\left(n\right)\backslash m}{\mathrm{\Σ}}{R}_{m^{\′}n}---\left(4\right)$

Step 64: reliability updating device 14 is with different inspection pointer Q _MnAdd and satisfy inspection node C _mDystopy pointer R when being zero _Mn, think a Node B _nReappraise just like the reliability index Q of equation (5) _n, wherein M (n) represent all can with the position Node B _nPass the inspection node C of message mutually _mWith Fig. 5 (c) is example, and reliability updating device 14 can set satisfy inspection node C ₂, C ₃Be that zero dystopy pointer is used as a Node B ₄Reliability index.

$Q_n=\ln \left[\frac{\mathrm{Pr}(B_n=0)}{\mathrm{Pr}(B_n=1)}\right]=Q_{\mathrm{START}\_n}+\underset{m\∈M\left(n\right)}{\mathrm{\Σ}}{R}_{\mathrm{mn}}---\left(5\right)$

In addition, observation equation formula (3) can be known dystopy pointer R _MnCan be along with channel quality ratio the V (=σ that estimates _UPDATE ²/ σ _START ²) adjust, and combine from other can with inspection node C _mPass the position Node B of message mutually _{N '}Institute's message transmitted.So equation (5) is adding dystopy pointer R _MnAfter, the reliability index Q that reappraises _nMust estimate reliability index Q than just _{START_n}Have more confidence level.

Step 65: demo plant 15 is based on this equipotential Node B _nReliability index Q _nWhether decision continues iterative computation.

And step 65 comprises the following substep like Fig. 8:

Substep 651: demo plant 15 is based on these reliability indexs Q _nUpgrade this equipotential Node B _n, and will upgrade position, back Node B _nSend remapper 3 to upgrade channel quality ratio V.As reliability index Q _nGreater than 0, demo plant 15 is with the position Node B _nBe updated to 0.As reliability index Q _nBe not more than 0, demo plant 15 is with the position Node B _nBe updated to 1.And with the increase of iteration metering, reliability index Q _nConfidence level high more, this is representing reliability index Q _nHave bigger absolute value.Because reliable indicator is with the position Node B _nMaybe for 0 probability with maybe be for the result of the ratio of 1 probability after taking the logarithm, so reliability index Q _nAbsolute value big more, upgrade position, back Node B _nMight be particular value (0 or 1) more.

Substep 652: demo plant 15 is multiplied by these (N) with low-density parity check (LDPC) matrix and upgrades position, back Node B ₀～B _N-1Obtain checking node C after (N-K) individual renewal ₀～C _N-K-1

Substep 653: whether demo plant 15 inspection iteration meterings are greater than an iteration critical value.If then finish decoding process; If not, continue substep 654.

Substep 654: these upgrade back inspection node C demo plant 15 inspections ₀～C _N-K-1Whether be zero entirely.If then finish decoding process, and get wherein k and upgrade position, a back node and be used as decoding output; If not, then demo plant 15 makes the iteration metering add 1, and rebound step 62 iteration calculates.

The reason of execution in step 65 is: demo plant 15 is reaffirmed these inspection nodes C with low-density parity check (LDPC) matrix ₀～C _N-K-1Whether be zero, and then infer this equipotential Node B ₀～B _N-1Can be similar in appearance to the transmission end output of LDPC encoder, to guarantee to reduce the interference of channel 7.And the consideration of channel quality ratio V also helps quicken these inspection nodes C in the step 62 ₀～C _N-K-1Converge to zero, reduce iterations simultaneously.

It should be noted that and also can exchange step 63,64 execution sequence.Be in the step 64, satisfy all can with the position Node B _nPass the inspection node C of message mutually _mBe under the zero prerequisite, reliability updating device 14 is earlier a position Node B _nProduce reliability index Q _n Switching exam device 13 again in step 63 with reliability index Q _nDeduction satisfies inspection node C _mDystopy pointer R when being zero _Mn, and the Node B that must put in place _nGive inspection node C _mDifferent inspection index Q _Mn

And it should be noted that in the present embodiment that reliability generation device 11 is based on just estimates channel variance σ _STARTProduce and just estimate reliability index Q _{START_n}, channel estimator 5 is based on channel variance σ _START, σ _UPDATEProduce channel quality ratio V.Yet, also can be based on other parameter that can represent channel quality during design circuit and come computing, for example: signal noise ratio (Signal-to-Noise Ration, SNR).

And exchange position device 16 is implemented in the aspect (like Fig. 9) at another, also can change the execution sequence of these subtrators 164,165 and section value cell 166,167.That is: after 122 screenings of minimum value screening unit, first section value cell 166 retrodeviates the first intercepting value that in-migration output one is not less than this renewal back skew according to first set point value and this renewal.That is to say that skew is the first intercepting value with first set point value after first set point value is not less than this renewal; Skew after upgrading less than this is the first intercepting value with this renewal back skew.In like manner, the second intercepting value of second section corresponding second set point value of value cell 167 outputs.Then, first subtrator 164 makes the first intercepting value deduct this renewal back skew and obtains first bit pointer; Second subtrator 165 makes the second intercepting value deduct this renewal back skew and obtains second bit pointer.At last, multiplex (MUX) unit 168 is again based on first bit pointer and second bit pointer output dystopy pointer R _Mn

And the another enforcement aspect (like Figure 10) of exchange position device 17 different with above-mentioned enforcement aspect be: the outputs (i.e. first bit pointer and second bit pointer) that multiplex (MUX) unit 178 directly receives these sections value cells 176,177 choose wherein one, deduct for first subtrator 174 and squint after this renewal and obtain first subtraction value.Then, multiplex (MUX) unit 178 is multiplied by symbol with first subtraction value again and indicates and produce dystopy pointer R _Mn

In addition, note that more the LDPC decoder 1 in the foregoing description is independently to start from receiving system 100.

In sum; Parity check (ldpc) decoders of the present invention and receiving system are utilized the channel quality ratio V after channel estimator 5 calculates each iteration, utilize multiplication to calculate by exchange position device 12,16,17 again and adjust dystopy pointer R with channel quality ratio V appositely _Mn, can effectively channel quality be reacted on decode procedure, improve confidence level, reduce iterations simultaneously and reduce computational complexity, so can reach the object of the invention really.

The above person of thought; Be merely preferred embodiment of the present invention; When not limiting the scope that the present invention implements with this, the simple equivalent of promptly doing according to claim scope of the present invention and invention description generally changes and modifies, and all still belongs in the scope that claim of the present invention contains.

Claims (16)

1. a receiving system is applicable to through channel to receive N modulating data through low density parity check code LDPC coding at least, comprises:

Channel estimator calculates the channel quality ratio of reacting this channel quality according to these modulating datas; And

The LDPC decoder obtains N position node at least according to these modulating datas, comprising:

Demo plant is multiplied by this N position node with low-density parity check (LDPC) matrix and obtains (N-K) individual inspection node, and each inspection node passes message mutually based on this matrix and at least two position nodes;

The reliability generation device for each node produces a reliable indicator, sends the different inspection index that can pass the inspection node of message with this node mutually to be used as this node;

Exchange position device based on this channel quality ratio and these different inspection indexs, for each inspection node produces at least two dystopy pointers, can check that node passes the position node of message mutually with this to send to respectively;

The switching exam device upgrades a plurality of different inspection pointers based on this isotonic pointer, supplies each node to send the inspection node that can pass message with this node mutually respectively to; And

The reliability updating device comes the reliable indicator of Refreshing Every position node according to these different inspection pointers, and then determines the updating value of each node,

Wherein, the reliable indicator after this demo plant upgrades based on these is upgraded this equipotential node, and is multiplied by these with this low-density parity check (LDPC) matrix and upgrades back position nodes and obtain checking node after (N-K) individual renewal; Afterwards, whether these renewal back inspection nodes of this demo plant inspection continue iterative computation with decision.

2. receiving system according to claim 1; Wherein, This exchange position device has the product unit and first subtrator; This product unit is multiplied by dystopy skew with this channel quality ratio and obtains a renewal back skew, and this first subtrator retrodeviates whole this isotonic pointer of transposition according to this renewal again.

3. based on the described receiving system of claim 2, wherein, this exchange position device also has:

The symbol decision unit will multiply each other except the symbol of different inspection pointer that a certain bits node external enwergy and an inspection node wherein pass other node of message mutually and export symbol indication;

The minimum value screening unit, from can with this wherein an inspection node pass mutually the different inspection index absolute value of position node of message, choose reckling and be used as first set point value, and choose time little person and be used as second set point value;

Second subtrator makes this second set point value deduct the skew of this renewal back and obtains second bit pointer, and this first subtrator makes this first set point value deduct this renewals back squinting and obtain first bit pointer; And

The multiplex (MUX) unit, that chooses this first bit pointer and this second bit pointer wherein one is multiplied by this symbol indication, wherein one checks that node sends the dystopy pointer of this certain bits node to obtain this.

4. receiving system according to claim 3; Wherein, This exchange position device also has first section value cell and second section value cell; This first section value cell is the symbol after subtracting each other according to this first subtrator and make this first bit pointer be not less than zero, and this second section value cell is the symbol after subtracting each other according to this second subtrator and make this second bit pointer be not less than zero.

5. receiving system according to claim 3; Wherein, This exchange position device also has first section value cell and second section value cell, and this first section value cell is to retrodeviate the in-migration adjustment according to this renewal to make this first set point value be not less than this renewal back skew, just is sent to this first subtrator; This second section value cell is to retrodeviate the in-migration adjustment according to this renewal to make this second set point value be not less than this renewal back skew, just is sent to this second subtrator.

6. based on the described receiving system of claim 2, wherein, this exchange position device also has:

The symbol decision unit will multiply each other except the symbol of different inspection pointer that a certain bits node external enwergy and an inspection node wherein pass other node of message mutually and export symbol indication;

The minimum value screening unit, from can with this wherein an inspection node pass mutually the different inspection index absolute value of position node of message, choose reckling and be used as first bit pointer, and choose time little person and be used as second bit pointer; And

The multiplex (MUX) unit, that chooses this first bit pointer and this second bit pointer wherein one is sent to this first subtrator;

And this first subtrator makes this wherein one deduct the skew of this renewal back and obtain first subtraction value, this multiplex (MUX) unit again with this first subtraction value be multiplied by this symbol indicate obtain this wherein an inspection node send the dystopy pointer of this certain bits node to.

7. receiving system according to claim 6; Wherein, This exchange position device also has first section value cell and second section value cell, and this first section value cell is to retrodeviate the in-migration adjustment according to this renewal to make this first bit pointer be not less than this renewal back skew, just is sent to this multiplex (MUX) unit; This second section value cell is to retrodeviate the in-migration adjustment according to this renewal to make this second bit pointer be not less than this renewal back skew, just is sent to this multiplex (MUX) unit.

8. receiving system according to claim 1 also comprises the reflection love dart, carries out just being sent to this channel estimator after rectification handles according to these modulating datas.

9. receiving system according to claim 1; Also comprise remapper; Reception is from the updating value of this equipotential node of LDPC decoder, and shines upon a plurality of mapping (enum) datas more according to this, cooperates these modulating datas to calculate this channel quality ratio for this channel estimator.

10. parity check (ldpc) decoders, be applicable to the channel quality ratio that receives the reaction channel quality with N encode through low density parity check code LDPC to be decoded at least, this decoder comprises:

Demo plant, looking each position to be decoded is a node, and is multiplied by this N position node with low-density parity check (LDPC) matrix and obtains (N-K) individual inspection node, and each inspection node passes message mutually based on this matrix and at least two position nodes;

The reliability generation device for each node produces a reliable indicator, sends a different inspection index that can pass the inspection node of message with this node mutually to be used as this node;

Exchange position device based on this channel quality ratio and these different inspection indexs, for each inspection node produces at least two dystopy pointers, can check that node passes the position node of message mutually with this to send to respectively;

The switching exam device upgrades a plurality of different inspection pointers based on this isotonic pointer, supplies each node to send the inspection node that this node of ability passes message mutually respectively to; And

The reliability updating device comes the reliable indicator of Refreshing Every position node according to these different inspection pointers, and then determines the updating value of each node,

Wherein, the reliable indicator after this demo plant upgrades based on these is upgraded this equipotential node, and is multiplied by these with this low-density parity check (LDPC) matrix and upgrades back position nodes and obtain checking node after (N-K) individual renewal; Afterwards, whether these renewal back inspection nodes of this demo plant inspection continue iterative computation with decision.

11. decoder according to claim 10; Wherein, This exchange position device has the product unit and first subtrator; This product unit is multiplied by dystopy skew with this channel quality ratio and obtains a renewal back skew, and this first subtrator retrodeviates whole this isotonic pointer of transposition according to this renewal again.

12. based on the described decoder of claim 11, wherein, this exchange position device also has:

The symbol decision unit will multiply each other except the symbol of different inspection pointer that a certain bits node external enwergy and an inspection node wherein pass other node of message mutually and export symbol indication;

The minimum value screening unit, from can with this wherein an inspection node pass mutually the different inspection index absolute value of position node of message, choose reckling and be used as first set point value, and choose time little person and be used as second set point value;

Second subtrator makes this second set point value deduct the skew of this renewal back and obtains second bit pointer, and this first subtrator makes this first set point value deduct this renewals back squinting and obtain first bit pointer; And

The multiplex (MUX) unit, that chooses this first bit pointer and this second bit pointer wherein one is multiplied by this symbol indication, wherein one checks that node sends the dystopy pointer of this certain bits node to obtain this.

13. decoder according to claim 12; Wherein, This exchange position device also has first section value cell and second section value cell; This first section value cell is the symbol after subtracting each other according to this first subtrator and make this first bit pointer be not less than zero, and this second section value cell is the symbol after subtracting each other according to this second subtrator and make this second bit pointer be not less than zero.

14. decoder according to claim 12; Wherein, This exchange position device also has first section value cell and second section value cell, and this first section value cell is to retrodeviate the in-migration adjustment according to this renewal to make this first set point value be not less than this renewal back skew, just is sent to this first subtrator; This second section value cell is to retrodeviate the in-migration adjustment according to this renewal to make this second set point value be not less than this renewal back skew, just is sent to this second subtrator.

15. based on the described decoder of claim 11, wherein, this exchange position device also has:

The symbol decision unit will multiply each other except the symbol of different inspection pointer that a certain bits node external enwergy and an inspection node wherein pass other node of message mutually and export symbol indication;

The minimum value screening unit, from can with this wherein an inspection node pass mutually the different inspection index absolute value of position node of message, choose reckling and be used as first bit pointer, and choose time little person and be used as second bit pointer; And

The multiplex (MUX) unit, that chooses this first bit pointer and this second bit pointer wherein one is sent to this first subtrator;

And this first subtrator makes this wherein one deduct the skew of this renewal back and obtain first subtraction value, this multiplex (MUX) unit again with this first subtraction value be multiplied by this symbol indicate obtain this wherein an inspection node send the dystopy pointer of this certain bits node to.

16. decoder according to claim 15; Wherein, This exchange position device also has first section value cell and second section value cell, and this first section value cell is to retrodeviate the in-migration adjustment according to this renewal to make this first bit pointer be not less than this renewal back skew, just is sent to this multiplex (MUX) unit; This second section value cell is to retrodeviate the in-migration adjustment according to this renewal to make this second bit pointer be not less than this renewal back skew, just is sent to this multiplex (MUX) unit.

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