CN101305575A - Method and apparatus for normalizing input metric to a channel decoder in a wireless communication system - Google Patents

Abstract

An apparatus and method are provided for normalizing input soft metric to a channel decoder in a wireless communication system. A demapper generates soft metric using an in-phase component (Xk) and a quadrature component (Yk) of a received modulated symbol (Rk), a channel fading coefficient (gk) and a constant value (c) defined by a modulation order of the received modulated symbol. A normalizer receives the soft metric, computes a normalized log likelihood ratio (LLR) by multiplying the soft metric by a ratio of the constant value to a noise variance value, transforms the normalized LLR into a desired range and a desired number of bits, and outputs an input LLR of the channel decoder.

Description

Normalize to the method and apparatus of the input tolerance of channel decoder in the wireless communication system

Technical field

The present invention relates generally to wireless communication system.More specifically, the present invention relates to be used to normalize to the method and apparatus of the input tolerance (metric) of channel decoder.

Background technology

CDMA 2000 (CDMA 2000), wideband CDMA (WCDMA) and Institute of Electrical and Electric Engineers (IEEE) 802.16 systems carry out Quadrature Phase Shift Keying (QPSK), 8PSK, 16 quadrature amplitude modulation (16-QAM), 64 quadrature amplitude modulation modulation systems such as (64-QAM).In addition, these systems carry out adaptive modulation and coding (AMC) in conjunction with the channel code such as the turbo code.This system obtains to be suitable for the optimal transmission rate of channel conditions.Receiver stage utilizes de-mapping device (demapper) to calculate the log-likelihood ratio (LLR) of every bit according to various modulation systems, and gets access to the input tolerance of channel decoder.This channel decoder receives and this tolerance of decoding.

Fig. 1 shows the structure of the transceiver in legacy wireless communication system.

With reference to Fig. 1, the binary data i (n) that coding will send in the channel encoder 110 within reflector 100.Channel encoder 110 produces a series of binary code symbol c (n).Mapper 120 produces the piece of several code signs of the code sign that is produced, and carries out the mapping of a point on the signal constellation (in digital modulation), and is transformed to the modulation symbol x (n) of complex values.Modulation symbol x (n) puts on the modulator 130.Modulator 130 is created in time continuous wave in code division multiple access (CDMA) or OFDM (OFDM) scheme according to modulation symbol x (n), and the ripple that is produced is sent to receiver 150 by channel 140.

In receiver 150, demodulator/channel-estimator 160 is carried out base band demodulating and channel estimation process to the received signal.Can realize this demodulator according to various technology.For example, this demodulator can be the ofdm demodulator of realizing with CDMA Rake receiver or invert fast fourier transformation (IFFT) processor and channel-estimator.After base band demodulating, the symbol y (n) that passes through QAM or PSK modulation that obtains channel estimation c (n) and receive.

De-mapping device 170 uses the symbol y (n) and the channel that receive to estimate that c (n) calculates the tolerance of the bit of the code word that constitutes channel code.The sequence Λ (n) corresponding with the metric that calculates in de-mapping device 170 is imported in the channel decoder 180, and is decoded into the binary data of original transmission.When channel decoder 180 was finished decode operation, receiver 150 was finished basic operation in physical layer.At this moment, channel decoder 180 can use Viterbi decoder for convolution code, for soft output Viterbi algorithm (SOVA) iterative decoder, logarithm maximum a posteriori probability (MAP) iterative decoder and the max log MAP iterative decoder etc. of turbo sign indicating number.

When the legacy wireless communication system that realizes working as mentioned above, when carrying out floating-point operation according to traditional approach, the dynamic range of tolerance that is input to decoder is unrestricted.Yet when realizing being used to carry out the hardware of fixed-point calculation, according to dynamic range, it is subjected to the influence of quantizing noise, clipped noise or the like.Therefore, each step of communication system all should be operated by the normalization that execution is suitable for measuring representation and be guaranteed that optimum performance has minimal hardware simultaneously.But because conventional method is not considered the normalization of the tolerance calculated in de-mapping device, therefore have a problem: the performance of high code rate and high order modulation is lower than the performance of traditional code rate and modulation.

Summary of the invention

Thereby particular exemplary embodiment of the present invention solves the above-mentioned and other problem that exists in the prior art.Exemplary aspect of the present invention provides the log-likelihood ratio (LLR) that utilizes a small amount of bit in a kind of wireless communication system when channel-decoding can obtain the method and apparatus of optimum performance.

In addition, one exemplary embodiment of the present invention provides a kind of method and apparatus that can improve decoding performance in wireless communication system by normalization as a small amount of bit of tolerance utilization of the input of channel decoder.

In addition, one exemplary embodiment of the present invention provide a kind of in wireless communication system according to the noise level of modulation order and current state suitably normalization be used as the method and apparatus of tolerance of the input of channel decoder.

In addition, one exemplary embodiment of the present invention provide a kind of in wireless communication system when lack as the input of channel decoder about the information of noise variable (noise variance) time can use about the information of modulation order, channel coding rate and chnnel coding frame length and carry out suitable normalized method and apparatus.

According to an exemplary aspect of the present invention, provide a kind of in wireless communication system normalization be input to the device of the soft metric of channel decoder.In exemplary enforcement, this device comprises: de-mapping device is used to use the modulation symbol (R that receives _k) in-phase component (X _k) and quadrature component (Y _k), channel fading coefficient (g _k) and produce soft metric by the constant value (c) of the modulation order of the modulation symbol that receives definition; And normalization device, be used to receive this soft metric, calculate normalized log likelihood ratio (LLR) by the ratio that this soft metric be multiply by this constant value and noise variate-value, this normalized LLR is transformed to the scope of expectation and the bit number of expectation, and the input LLR of delivery channel decoder.

According to another exemplary aspect of the present invention, provide a kind of in wireless communication system normalization be input to the device of the soft metric of channel decoder.In exemplary enforcement, this device comprises: de-mapping device is used to use the modulation symbol (R that receives _k) in-phase component (X _k) and quadrature component (Y _k), channel fading coefficient (g _k) and produce soft metric by the constant value (c) of the modulation order of the modulation symbol that receives definition; And normalization device, be used to receive this soft metric, calculate normalized log likelihood ratio (LLR) by the normalization coefficient that this soft metric be multiply by by adaptive modulation and coding (AMC) information calculations, this normalized LLR is transformed to the scope of expectation and the bit number of expectation, and the input LLR of delivery channel decoder.

According to another exemplary aspect of the present invention, provide a kind of in wireless communication system normalization be input to the method for the soft metric of channel decoder.In exemplary enforcement, this method comprises: use the modulation symbol (R that receives _k) in-phase component (X _k) and quadrature component (Y _k), channel fading coefficient (g _k) and produce soft metric by the constant value (c) of the modulation order of the modulation symbol that receives definition; Receive this soft metric, and calculate normalized log likelihood ratio (LLR) by the ratio that this soft metric be multiply by this constant value and noise variate-value; And this normalized LLR transformed to the scope of expectation and the bit number of expectation, and the input LLR of delivery channel decoder.

According to another exemplary aspect of the present invention, provide a kind of in wireless communication system normalization be input to the method for the soft metric of channel decoder.In exemplary enforcement, this method comprises: use the modulation symbol (R that receives _k) in-phase component (X _k) and quadrature component (Y _k), channel fading coefficient (g _k) and produce soft metric by the constant value (c) of the modulation order of the modulation symbol that receives definition; Receive this soft metric, and calculate normalized log likelihood ratio (LLR) by the normalization coefficient that this soft metric be multiply by by adaptive modulation and coding (AMC) information calculations; And this normalized LLR transformed to the scope of expectation and the bit number of expectation, and the input LLR of delivery channel decoder.

Description of drawings

By the detailed description below in conjunction with accompanying drawing, above-mentioned and further feature of the present invention and advantage will become and be more readily understood, and in the accompanying drawings, identical referenced drawings numeral will be understood that to refer to components identical, feature and structure, wherein:

Fig. 1 shows the structure of transceiver in legacy wireless communication system;

Fig. 2 has shown according to the application of first one exemplary embodiment of the present invention the structure of the transceiver of input tolerance normalization device;

Fig. 3 A shows Quadrature Phase Shift Keying (QPSK) constellation and mapping;

Fig. 3 B shows 16 quadrature amplitude modulation (16-QAM) constellation and mapping;

Fig. 3 C shows 64 quadrature amplitude modulation (64-QAM) constellation and mapping;

Fig. 4 shows the example of calculating soft metric;

Fig. 5 shows the work structuring according to the input tolerance normalization device of first one exemplary embodiment of the present invention;

Fig. 6 shows another work structuring according to the input tolerance normalization device of first one exemplary embodiment of the present invention;

Fig. 7 shows frame error rate (FER) performance of additive white Gaussian noise (AWGN) channel;

Fig. 8 has shown according to the application of second one exemplary embodiment of the present invention the structure of the transceiver of input tolerance normalization device;

Fig. 9 shows the work structuring according to the input tolerance normalization device of second one exemplary embodiment of the present invention;

Figure 10 shows another work structuring according to the input tolerance normalization device of second one exemplary embodiment of the present invention;

Figure 11 shows the another work structuring according to the input tolerance normalization device of second one exemplary embodiment of the present invention;

Figure 12 shows the performance that puts on according to the convolution turbo decoder of the 6 bits input tolerance of the tolerance normalization device of first and second one exemplary embodiment of the present invention; And

Figure 13 shows the performance that puts on according to the convolution turbo decoder of the 6 bits input tolerance of the tolerance normalization device of first and second one exemplary embodiment of the present invention.

Embodiment

Describe the operation principle of one exemplary embodiment of the present invention below with reference to accompanying drawings in detail.In the following description, clear for the sake of simplicity, will omit the detailed description that well known to a person skilled in the art function and structure that is herein incorporated.Term that should be appreciated that here to be adopted and term should not be considered to be used to limit the present invention only for purpose of description.

One exemplary embodiment of the present invention provides a kind of method and apparatus that utilizes log-likelihood ratio (LLR) the tolerance acquisition optimum solution code performance of a small amount of bit when encoding channel.Particular exemplary execution mode of the present invention utilizes the feasible decoding performance that improved of a small amount of bit by the input tolerance of normalization channel decoder.

＜the first one exemplary embodiment 〉

First one exemplary embodiment of the present invention provides a kind of utilization to carry out normalized structure and operating process as the information about the noise variable of the input of channel decoder.

Fig. 2 has shown according to the application of first one exemplary embodiment of the present invention the structure of the wireless communication transceiver of input tolerance normalization device.

With reference to Fig. 2, the binary data i (n) that coding will send in the channel encoder 210 within reflector 200.Channel encoder 210 produces a series of binary code symbol c (n).Mapper 220 produces the piece of several code signs of the code sign that is produced, and is mapped to a point on the signal constellation (in digital modulation), and is transformed to the modulation symbol x (n) of complex values.Sequence x (n) puts on the modulator 230.Modulator 230 is according to this symbol generation time continuous wave in code division multiple access (CDMA) or OFDM (OFDM) scheme, and the ripple that is produced is sent to receiver 250 by channel 240.

In receiver 250,260 pairs of signals through channel 240 of demodulator/channel-estimator are carried out base band demodulating and channel estimation process.Can realize this demodulator according to the various technology that are applied to base band.For example, this demodulator can be the ofdm demodulator of realizing with CDMA Rake receiver or invert fast fourier transformation (IFFT) processor and channel-estimator.

In one exemplary embodiment of the present invention, Institute of Electrical and Electric Engineers (IEEE) 802.16e and OFDM (OFDMA) system will be described mainly.After demodulator/channel-estimator 260 has been finished base band demodulating, symbol and the channel estimation that receives outputed in noise variable estimation device 265 and the de-mapping device 270.Noise variable estimation device 265 uses various algorithms to come estimated noise variate-value σ according to channel estimation _n ², and with the estimation the noise variate-value output to LLR normalization device 275.

De-mapping device 270 receive channel from demodulator/channel-estimator 260 is estimated c (n) and the symbol y (n) that receives that modulates by quadrature amplitude modulation (QAM) or phase shift keying (PSK), and exports the tolerance of every bit by separating mapping.De-mapping device 270 can use various algorithms to obtain this tolerance.De-mapping method uses the shortcut calculation that approaches optimal algorithm traditionally.One of this multiple algorithm is at list of references 1 (Y.Xu, H.-J.Su, E.Geraniotis, " Pilot symbol assisted QAM withinterleaved filtering and turbo decoding over Rayleigh flat-fading channel; " inProc.MILCOM ' 99, pp.86-91) the two minimum metric methods that propose in, its disclosure is incorporated in this by reference.

IEEE 802.16e system uses the high order modulation of 16 quadrature amplitude modulation (16-QAM) or 64 quadrature amplitude modulation (64-QAM).Because channel fading and noise, the signal that the modulation back sends may distortion.Owing to the reception of convolution turbo decoder and the decoding soft metric corresponding of in the receiver 250 of IEEE 802.16 systems, serving as channel decoder 280, therefore need from the signal that receives of distortion, calculate the process of soft metric in the prime of channel decoder 280 with the reliability information of every bit.This process is carried out by the de-mapping device in the receiver 250 270.Now, description is applied to the mapping algorithm of separating of the present invention.

IEEE 802.16 systems use the modulator approach of Quadrature Phase Shift Keying (QPSK), 16QAM or 64QAM.When the bit number of a modulation symbol in the output sequence of representing the binary channel encoder was m, the signal in the constellation was counted and is M=2 ^m, m=2 wherein, 4,6 or the like.This m bit is mapped as the signal specific point of signaling point.When expressing the M-QAM mapping with an equation, from m binary character shown in equation (1), can obtain the homophase and the quadrature component of modulation symbol.

$s_{k,m-1},s_{k,m-2},...,s_{k,0}\stackrel{M-\mathrm{QAM}}{\→}{x}_k,y_k......\left(1\right)$

In equation (1), s _{K i}(i=0,1 ..., m-1) be i the symbol of output sequence that is mapped to the binary channel encoder of k signaling point, x _kAnd y _kBe respectively the in-phase component and the quadrature component of k signaling point.Under the situation of 16QAM, m=4.

Fig. 3 A shows QPSK constellation, 16QAM constellation and 64QAM constellation respectively to 3C.

As can be seen, the x of modulated symbol from Fig. 3 A to 3C _kBy s _{K m-1}, s _{K, m-2}..., s _{K m/2}Determine, and y _kBy s _{K m/2 1}..., s _{K 0}Determine.The constant c that can determine each constellation point is defined by equation (2).This is that the average energy that is used for symbol is set to 1 value.

${\mathrm{<figure-callout\; id="4"\; label="c"\; filenames="A20068004211400411.png"\; state="\{\{state\}\}">c</figure-callout>}}_4=\frac{1}{\sqrt{2}}=0.70711$

${\mathrm{<figure-callout\; id="16"\; label="c"\; filenames="A20068004211400321.png,A20068004211400351.png"\; state="\{\{state\}\}">c</figure-callout>}}_{16}=\frac{1}{\sqrt{10}}=0.3162$

$c_{64}=\frac{1}{\sqrt{42}}=0.1543......\left(2\right)$

Here, c ₄Be the reference value of QPSK, c ₁₆Be the reference value of 16QAM, c ₆₄Reference value for 64QAM.Symbol after the modulation has x _k+ jy _kComplex values.Symbol after modulation is through after channel 240 and the base band demodulator 260, and the signal shown in equation (3) is input in the de-mapping device 270.

R _k＝g _k(x _k+jy _k)+n _xk+jn _yk......(3)

＝X _K+jY _K

Here, g _kFor the channel fading coefficient and be expressed as g _k=g _Xk+ jg _YkN _XkAnd n _YkBe noise and interference components.The bit symbol s corresponding with the element of qam symbol _{K, i}Log-likelihood ratio (LLR) can be similar to shown in equation (4).

$\widetilde{\mathrm{\&Lambda;}}\left(s_{k,i}\right)=\log \frac{\mathrm{Pr}\{s_{k,i}=0|X_k,Y_k\}}{\mathrm{Pr}\{s_{k,i}=1|X_k,Y_k\}}$

$=\log \frac{\underset{z_k}{\mathrm{\&Sigma;}}\exp \left\{\frac{-1}{{\mathrm{\&sigma;}}_{\mathrm{<figure-callout\; id="2"\; label="n"\; filenames="A20068004211400351.png,A20068004211400411.png"\; state="\{\{state\}\}">n</figure-callout>}}^2}{|R_k-z_k(s_{k,i}=0)|}^2\right\}}{\underset{z_k}{\mathrm{\&Sigma;}}\exp \left\{\frac{-1}{{\mathrm{\&sigma;}}_{\mathrm{<figure-callout\; id="2"\; label="n"\; filenames="A20068004211400351.png,A20068004211400411.png"\; state="\{\{state\}\}">n</figure-callout>}}^2}{|R_k-z_k(s_{k,i}=1)|}^2\right\}}......\left(4\right)$

$\&ap;\log \frac{\exp \left\{\frac{-1}{{\mathrm{\&sigma;}}_{\mathrm{<figure-callout\; id="2"\; label="n"\; filenames="A20068004211400351.png,A20068004211400411.png"\; state="\{\{state\}\}">n</figure-callout>}}^2}\min {|R_k-z_k(s_{k,i}=0)|}^2\right\}}{\exp \left\{\frac{-1}{{\mathrm{\&sigma;}}_{\mathrm{<figure-callout\; id="2"\; label="n"\; filenames="A20068004211400351.png,A20068004211400411.png"\; state="\{\{state\}\}">n</figure-callout>}}^2}\min {|R_k-z_k(s_{k,i}=1)|}^2\right\}}$

$=\frac{1}{{\mathrm{\&sigma;}}_n^2}[\min {|R_k-z_k(s_{k,i}=1)|}^2-\min {|R_k-z_k(s_{k,i}=0)|}^2]$

Here, z _k(s _{K, i}=0) for passing through with s _{K, i}=0 symbol multiply by decline constant g _kThe constellation point of the change of calculating, σ _n ²Be noise and disturbance variable.

In equation (4), use logarithm maximum a posteriori probability (MAP) scheme and calculate LLR, use low computational effort can obtain highly reliable estimation.Equation (4) can be similar to shown in equation (5).

$\widetilde{\mathrm{\&Lambda;}}\left(s_{k,i}\right)=\frac{1}{{\mathrm{\&sigma;}}_n^2}({2n}_{k,i}-1)[{|R_k-z_k(s_{k,i}=n_{k,i})|}^2-\min {|R_k-z_k(s_{k,i}={\stackrel{\&OverBar;}{n}}_{k,i})|}^2]......\left(5\right)$

Here, n _{K, i}For being mapped to the symbol R that approaches to receive _kI information bit value of constellation point, n _{K, i}Be n _{K, i}Negate (negation).Constitute QPSK, the bit symbol s of 16QAM and 64QAM symbol _{K, i}Only relevant respectively with one of the homophase of the symbol that receives and quadrature component.R about equation (5) _kAnd z _k, according to s _{K, i}Estimate one of x and y axle component.

Fig. 4 shows and works as g _kCalculate the example of LLR during for real number value.

Suppose and receive R _k, can define s by equation (6) as shown in Figure 4 ₃LLR.

$\widetilde{\mathrm{\&Lambda;}}\left(s_{k,3}\right)=\frac{1}{{\mathrm{\&sigma;}}_n^2}(-1)[{|X_k-3{\mathrm{<figure-callout\; id="16"\; label="g\; k\; c"\; filenames="A20068004211400321.png,A20068004211400351.png"\; state="\{\{state\}\}">g</figure-callout>}}_k{c}_{}{}_{16}|}^2-{|X_k+{\mathrm{<figure-callout\; id="16"\; label="g\; k\; c"\; filenames="A20068004211400321.png,A20068004211400351.png"\; state="\{\{state\}\}">g</figure-callout>}}_k{c}_{}{}_{16}|}^2]......\left(6\right)$

$=\frac{4{\mathrm{<figure-callout\; id="16"\; label="c"\; filenames="A20068004211400321.png,A20068004211400351.png"\; state="\{\{state\}\}">c</figure-callout>}}_{16}}{{\mathrm{\&sigma;}}_n^2}(2{\left|g_k\right|}^2{X}_k-2{\left|g_k\right|}^2{c}_{16})$

When the method for use shown in equation (6) calculated LLR, all there is coefficient under every kind of situation

And the part in the bracket is the linear equality for input signal.In exemplary embodiment, can utilize the linear function of soft metric generator (SMG) to realize de-mapping device.Comprising fading coefficients g _kConstant when being input among the SMG, can handle this constant with suitable calibration (scale) method.Suppose and be used for by estimating coefficient from LLR The function that produces soft metric is that (a, b), the equation (6) that then is used to calculate LLR can be rewritten as equation (7) to SMG.

$\widetilde{\mathrm{\&Lambda;}}\left(s_{k,i}\right)=\frac{4c}{{\mathrm{\&sigma;}}_{\mathrm{<figure-callout\; id="2"\; label="n"\; filenames="A20068004211400351.png,A20068004211400411.png"\; state="\{\{state\}\}">n</figure-callout>}}^2}\mathrm{SM}{G}_i({\left|g_k\right|}^2{X}_k,{\left|g_k\right|}^{2}c)......\left(7\right)$

$=\frac{4c}{{\mathrm{\&sigma;}}_{\mathrm{<figure-callout\; id="2"\; label="n"\; filenames="A20068004211400351.png,A20068004211400411.png"\; state="\{\{state\}\}">n</figure-callout>}}^2}\mathrm{\&Lambda;}\left(s_{k,i}\right)$

Equation (7) only shows and in-phase component X _kRelevant LLR calculates.Certainly, only with quadrature component Y _kRelevant LLR calculates and can use | g _k| ²Y _kReplace | g _k| ²X _k

The input of SMG is | g _k| ²X _k, | g _k| ²Y _kWith | g _k| ²C, wherein g _kObtain by the channel estimation.Thereby, the input that can easily calculate SMG by symbol that receives and channel estimation.

Work as g _kWhen being plural number, the input that is mapped to the SMG of in-phase signal component and quadrature signal component can define shown in equation (8).

$R_k{g}_k^{*}=({X_k}^{\&prime;}+j{Y}_k)(g_{\mathrm{xk}}-j{g}_{\mathrm{yk}})$

$=(X_k{g}_{\mathrm{xk}}+Y_k{g}_{\mathrm{yk}})+j(Y_k{g}_{\mathrm{xk}}-X_k{g}_{\mathrm{yk}})......\left(8\right)$

$={\left|g_k\right|}^2{X}_k+j{\left|g_k\right|}^2{Y}_k$

That is to say that the input of SMG can easily use equation (9) to calculate by the signal that receives in the equation (8).

(X _kg _xk+Y _kg _yk，|g _k| ²c)＝(I _k，a _k)

(Y _kg _xk-Y _kg _yk，|g _k| ²c)＝(Q _k，a _k)......(9)

Coefficient between the output that is attached to SMG jointly In, value 4 is QPSK, the common coefficient of 16QAM and 64QAM, and therefore reflection quantizes.Be provided with

Thereby make and after producing soft output, carry out normalization, and the LLR that quantizes has suitable scope and resolution.

Then, will can be reduced to shown in equation (10) SMG in the tolerance of calculating in the de-mapping device 270 _iThe function of () is simple linear calculating of only utilizing shifting function and adder to implement.

$\mathrm{\&Lambda;}\left(s_{k,i}\right)={\mathrm{SMG}}_i(I_k,a_k)$

$=\frac{{2n}_{k,i}-1}{4c}[{|R_k-z_k(s_{k,i}=n_{k,i})|}^2-\min {|R_k-z_k(s_{k,i}={\stackrel{\&OverBar;}{n}}_{k,i})|}^2]......\left(10\right)$

Here, a _kFor | g _k| ²C.Equation (10) is used to calculate the soft metric relevant with in-phase component.SMG _i(Q _k, a _k) be used for calculating and the relevant soft metric of quadrature component shown in the equation (7).

As shown in the table, by function S MG _iThe tolerance of the 16QAM that () obtains can be according to the in-phase signal component I by the sign computation that receives _kWith quadrature signal component Q _kAnd the territory under the channel fading coefficient obtains.In order to calculate soft metric, only consider I _k, Q _kAnd a _k

Table 1

I kCondition	Λ(s k，3)	Λ(s k，2)
			I k＞2a k	2I k-2a k	2a k-I k
0＜I k≤2a k	I k	2a k-I k
			-2a k＜I k≤0	I k	I k+2a k
I k≤-2a k	2I k+2a k	I k+2a k

Table 2

Q kCondition	Λ(s k，1)	Λ(s k，0)
			Q k＞2a k	2Q k-2a k	2a k-Q k
0＜Q k≤2a k	2Q k-2a k	2a k-Q k
			-2a k＜Q k≤0	Q k	Q k+2a k
Q k≤-2a k	2Q k+2a k	Q k+2a k

Table 1 shows by I _kThe tolerance of the 16QAM that produces, table 2 shows by Q _kThe tolerance of the 16QAM that produces.In an identical manner, can calculate the Λ (s relevant with 64QAM _{K, 5}), Λ (s _{K, 4}) and Λ (s _{K, 3}) soft bit metric, as shown in table 3.In addition, can be by Q _kCalculate Λ (s _{K, 2}), Λ (s _{K, 1}) and Λ (s _{K, 0}).To describe below and I _kRelevant soft output.

Table 3

I kCondition	Λ(s k，5)	Λ(s k，4)	Λ(s k，3)
				I k＞6a k	4I k-12a k	10a k-2I k	6a k-I k
4a k＜I k≤6a k	3I k-6a k	4a k-I k	6a k-I k
				2a k＜I k≤4a k	2I k-2a k	4a k-I k	I k-2a k
0＜I k≤-2a k	I k	6a k-2I k	I k-2a k
				-2a k＜I k≤0	I k	6a k+2I k	-I k-2a k
-4a k＜I k≤-2a k	2I k+2a k	4a k+I k	-I k-2a k
				-6a k＜I k≤-4a k	3I k+6a k	4a k+I k	6a k+I k
I k≤-6a k	4I k+12a k	10a k+2I k	6a k+I k

Table 3 shows by I _kThe soft metric of the 64QAM that produces.Make in this way, can calculate the soft output of QPSK, 16QAM and 64QAM.But soft output value itself is to remove 4c/ σ by the equation (7) from the original input LLR that is used for expressing decoder _n ²Calculate.

In the exemplary hardware execution mode, the dynamic range of the input of decoder tolerance may additionally increase, and perhaps its performance may be degenerated.Therefore, c/ σ _n ²Be reflected in the normalization.

Fig. 5 shows the exemplary embodiment according to the work structuring of the input tolerance normalization device of first one exemplary embodiment of the present invention.

Fig. 5 shows and is used to reflect c/ σ _n ²The example of tolerance normalization device of value.Because " c " value is stored according to QPSK, 16QAM and 64QAM modulation scheme, so normalization device 275 can be provided with " c " value when receiving the modulation order or being mapped to the modulation intelligence mod_order that modulates order.In order to calculate the noise variable σ corresponding with the summation variable of interference with noise _n ², need noise variable estimation device (as indicated) by the reference number 265 of Fig. 2.Noise variable estimation device 265 can use various algorithm estimated noise variate-value σ _n ²

In normalization device 275, multiplier 520 receives the c/ σ that the variate-value conversion is calculated by the map table 510 that uses the reflection division _n ²When multiplier 520 will multiply by c/ σ from the tolerance Λ (n) of de-mapping device 270 _n ²The time, normalization LLR.After normalization LLR, round off/truncation part 530 will have expected range and the expectation bit number LLR Λ ' (n) be input in the decoder.According to modulation order or the code rate that system supports, the bit number M of input tolerance is approximately 24～26, and normalized output bit number is 6～8.

In Fig. 5, can make in all sorts of ways the estimated noise variable.For example, can use list of references 1 (T.A.Summers and S.G.Wilson, " SNR mismatch and online estimation inturbo decoding; " IEEE Trans.Commun.vol.46, no.4, Apr.1998) disclosed method in, its disclosed content is herein incorporated by application.In addition, can estimate the variable (that is, noise variable) relevant with interference by the pilot channel of cdma system or the pilot tone of ofdm system with noise.

Fig. 6 shows another exemplary embodiment according to the work structuring of the input tolerance normalization device of first one exemplary embodiment of the present invention.

Fig. 6 shows the example of the normalization device of realizing Fig. 5.Utilize two shift units 630 and 640 and adders 650 to realize normalization.This normalization structure can be carried out suitable normalization minimise power consumption simultaneously.

In Fig. 6, modulation order (mod_order) and noise variable are input in the normalization index calculation device 610, make to calculate normalization index (norm_index).

Then, the example of method for normalizing will be described in detail.This normalization index calculation device 610 has the temp_norm_index that is mapped to the estimated value that can receive from noise variable estimation device 265.Owing to should reflect divided by the noise variable, therefore should select the temp_norm_index that is inversely proportional to the noise variate-value.For example, should select temp_norm_index so that $\left[\mathrm{Gain}(\mathrm{temp}\_\mathrm{norm}\_\mathrm{index})\left(\mathrm{dB}\right)\right]+\left[{\mathrm{\&sigma;}}_n^2\left(\mathrm{dB}\right)\right]+a=0.$ Only, " a " is relevant with the working range of noise and data channel value and constant definition.Gain and noise estimation need carry out the logarithmic function computing and be expressed by the dB scale.In addition, [.] expression is transformed into the integer that approaches to import most.Multiply by the constant c that changes along with the modulation order in order to reflect, the calculating below using obtains the norm_index value.

norm_index＝temp_norm_index， (QPSK)

norm_index＝temp_norm_index-2，(16QAM)

norm_index＝temp_norm_index-4，(64QAM)

In normalization table 620, the norm_index value is transformed into the normalized gain value that multiply by the normalization coefficient shown in the table 4.In a step-length (step) of table 4, may regulate the LLR normalization of about 3dB.Only can more accurate adjusting and when the LLR bit number will be reduced, the normalization coefficient of table 4 can be divided into more accurate step-length and can use a plurality of adders.

Then, by the norm_index value that calculates with normalization coefficient on duty is imported in shift unit 630 and 640, and be used for the tolerance Λ (n) from de-mapping device 270 is carried out shifting function.The value addition that in adder 650, will be shifted, thus LLR calculated.Normalized LLR is imported into and rounds off/truncation part 660 in.From round off and truncation part 660 output expected range and the expectation bit number LLR Λ ' (n).

Table 4

NORM_INDEX	Gain
		‘0’00000	96
‘1’00001	64
		‘2’00010	48
‘3’00011	32
		‘4’00100	24
‘5’00101	16
		‘6’00110	12＝8+4
‘7’00111	8
		‘8’01000	6＝4+2
‘9’01001	4
		‘10’01010	3＝2+1
‘11’01011	2
		‘12’01100	1.5＝1+1/2
‘13’01101	1
		‘14’01110	0.75＝1/2+1/4
‘15’01111	0.5
		‘16’10000	0.375＝1/4+1/8
‘17’10001	0.25
		‘18’10010	0.1875＝1/8+1/16
‘19’10011	0.125
		‘20’10100	0.09375＝1/16+1/32
’21’10101	0.0625
		‘22’10110	0.046875＝1/32+1/64
‘23’10111	0.03125
		‘24’-‘31’	-

Above-mentioned method for normalizing is to implement normalized example in the channel decoder of the system that uses QPSK, 16QAM and 64QAM.Certainly, the present invention includes all possible method of the output LLR of the SMG that uses noise estimation and modulation order.

＜the second one exemplary embodiment 〉

Exist to be difficult to calculate in the communication system situation of noise variate-value accurately, this is different from first one exemplary embodiment.Inerrably under the situation near the shannon limit of channel capacity, when predetermined signal to noise ratio (snr), having noise threshold, when higher SNR, can errorlessly transmit such as the chnnel coding of turbo sign indicating number and low-density checksum (LDPC) sign indicating number.That is to say that if modulation order, code rate and frame size are set, then the SNR of operating area is defined as those SNR of the required frame error rate of the system that can reach (FER) in the communication system of using multiple modulator approach and code rate.When this SNR of predefine in system, it can be used for the normalization of LLR.

In exemplary embodiment, in the time in system, modulation system and code rate can being set, can obtain desired value by system emulation.

Fig. 7 shows in IEEE 802.16e system and reaches for QPSK ¹/ ₂Coding, QPSK reach ³/ ₄Coding and 16QAM reach ¹/ ₂The FER performance of additive white Gaussian noise (AWGN) channel of coding.

With reference to Fig. 7, when the required FER of system is approximately 1%, reach at QPSK ¹/ ₂Carrier-in-interference noise ratio (CINR) zone of static state operation is approximately 2～3dB under the situation of coding.Even because when the normalization of LLR is not the best, the CINR in surpassing the SNR zone of about 2～3dB is enough height also, so FER fully reduced, so the performance of whole system is unaffected.Under the situation of low CINR, FER has the value that approaches " 1 ", and no matter LLR normalization how.

Therefore, even use the predefine value and during without the noise variable of actual measurement, the normalized performance of LLR also can be degenerated hardly in system.When knowing the signal power that obtains by automatic gain control substantially, defined SNR, thereby also can detect the noise variate-value.Reach at QPSK ¹/ ₂Under the situation of coding, suppose that the basic operation band has 3dB.In addition, suppose that application automatic gain loop and signal power P are constants, the noise variable that is mapped to the CINR of signal power P and 3dB has the relation shown in the equation.

$20{\log }_{10}\left(\frac{P}{{\widehat{\mathrm{\&sigma;}}}_n^2}\right)=3......\left(11\right)$

That is to say that the noise variable is by defining shown in the equation.

${\widehat{\mathrm{\&sigma;}}}_{\mathrm{<figure-callout\; id="2"\; label="n"\; filenames="A20068004211400351.png,A20068004211400411.png"\; state="\{\{state\}\}">n</figure-callout>}}^2=\frac{\mathrm{<figure-callout\; id="10"\; label="P"\; filenames="A20068004211400302.png,A20068004211400321.png"\; state="\{\{state\}\}">P</figure-callout>}}{{10}^{0.15}}......\left(12\right)$

Reach at QPSK ¹/ ₂Under the situation of coding,, also can access optimum performance when using the noise variate-value of pre-stored to carry out the normalization of LLR even then do not calculate actual noise variate-value at every turn if the noise variable that calculates is pre-stored in the receiver.

In second one exemplary embodiment of the present invention, based on AWGN, CINR is fixed to about 3dB.Under exemplary case, the qam symbol that constitutes a frame is because staggered etc. former thereby be subjected to almost independently declining.Compare 1% the FER that the system that reaches is required when higher CINR with AWGN.Thereby, when exemplary case, should consider that FER is provided with the noise variate-value in the system of being pre-stored in.Having described QPSK reaches ¹/ ₂The example of coding.Certainly, even also can be in a like fashion when selecting other modulation order and other code rate.

In exemplary embodiment, the automatic gain controller of system (AGC) operate as normal under the situation of above-mentioned configuration, and little apart from the variation of ideal value.

Fig. 8 has shown according to the application of second one exemplary embodiment of the present invention the structure of the wireless communication transceiver of tolerance normalization device.

With reference to Fig. 8, the binary data i (n) that coding will send in the channel encoder 810 within reflector 800.Channel encoder 810 produces a series of binary code symbol c (n).Mapper 820 produces the piece of several code signs of the code sign that is produced, and is mapped to a point on the signal constellation (in digital modulation), and is transformed to the modulation symbol x (n) of complex values.Sequence x (n) puts on the modulator 830.Modulator 830 produces time continuous wave in CDMA or the OFDM scheme according to this symbol, and the ripple that is produced is sent to receiver 850 by channel 840.

In receiver 850,860 pairs of signals through channel 840 of demodulator/channel-estimator are carried out base band demodulating and channel estimation process.Can realize this demodulator according to the various technology that are applied to base band.For example, this demodulator can be the ofdm demodulator of realizing with CDMA Rake receiver or IFFT processor and channel-estimator.

Channel estimation that obtains after the baseband modulation and the symbol that receives output to the de-mapping device 870 from demodulator/channel-estimator 860.De-mapping device 870 receives from the channel of demodulator/channel-estimator 860 estimates c (n) and the symbol y (n) that passes through QAM or PSK modulation that receives, and by separating the tolerance of the every bit of mapping output.De-mapping device 870 can use multiple algorithm to obtain tolerance.Can use the mapping algorithm of separating with reference to Fig. 2 description.

Owing to the reception of convolution turbo decoder and the decoding soft metric corresponding of in the receiver 850 of IEEE 802.16 systems, serving as channel decoder 880, therefore need from the signal that receives of distortion, calculate the process of soft metric in the prime of channel decoder 880 with the reliability information of every bit.This process is carried out by the de-mapping device in the receiver 850 870.

According to from the tolerance Λ (n) of de-mapping device 870 output and come the above-mentioned modulation system of self-controller 865 and adaptive modulation and coding (MAC) information of code rate, LLR normalization device 875 receives and the predefined noise variate-values of normalization.Channel decoder 880 receives normalized value Λ ' (n) and export i (n) then.

Fig. 9 shows the exemplary embodiment according to the work structuring of the input tolerance normalization device of second one exemplary embodiment of the present invention.

In Fig. 9, use predefined noise argument table according to the AMC information of modulation system and code rate.With reference to Fig. 9, noise argument table 910 storages of normalization device 875 are according to " c " value of the modulation scheme of QPSK, 16QAM and 64QAM.When receiving such as AMC information such as modulation order, code rate, frame sizes, normalization device 875 can be according to being provided with reference to " c " value by AMC information predetermined noise level and modulation order.

In normalization device 875, multiplier 930 receives the c/ σ that the map table 920 by using the reflection division calculates noise variate-value and reference " c " value transform _n ²When multiplier 930 will multiply by c/ σ from the tolerance Λ (n) of de-mapping device 870 _n ²The time, normalization LLR.After normalization LLR, round off/truncation part 940 will have expected range and the expectation bit number LLR Λ ' (n) be input in the decoder.

Figure 10 shows another exemplary embodiment according to the work structuring of the input tolerance normalization device of second one exemplary embodiment of the present invention.

In Figure 10, one group of normalization coefficient of normalization device predefine replaces the map table 920 of Fig. 9, only receives the normalization index, and normalization coefficient is set.

Normalization index receiver 1010 receives the information about modulation order, code rate, frame size etc., and the normalization index that wherein can reflect " c " value and noise variate-value is set, and the normalization of exporting this setting indexes in the normalization table 1020.Can use predefined table that the normalization index value is set.

When receiving set normalization index, can one group of possible normalization coefficient of predefine in normalization table 1020.When receiving the normalization index, normalization coefficient is set.When multiplier 930 will be from the tolerance Λ (n) of de-mapping device 870 when multiply by normalization coefficient, LLR is by normalization.After normalization LLR, round off/truncation part 1040 will have expected range and the expectation bit number LLR Λ ' (n) be input in the decoder.

Figure 11 shows the another exemplary embodiment according to the work structuring of the input tolerance normalization device of second one exemplary embodiment of the present invention.

Figure 11 shows the structure that obtains by the structure of simplifying Figure 10.Utilize two shift units 1130 and 1140 and adders 1150 to realize normalization.This normalization structure can be carried out suitable normalization minimise power consumption simultaneously.

Information about modulation system and code rate (or forward error correction (FEC) type of coding) is imported in the normalization index calculation device 1110, makes to calculate normalization index (norm_index).In normalization table 1120, the norm_index value of calculating is transformed into the normalized gain value that multiply by the normalization coefficient shown in the table 4.In a step-length of table 4, may regulate the LLR normalization of about 3dB.Only can more accurate adjusting and when the LLR bit number will be reduced, the normalization coefficient of table 4 can be divided into more accurate step and can use a plurality of adders.

Then, by the norm_index value that calculates with normalization coefficient on duty is imported in shift unit 1130 and 1140, and be used for the tolerance Λ (n) from de-mapping device 870 is carried out shifting function.The value addition that in adder 1150, will be shifted, thus LLR calculated.Normalized LLR is imported into and rounds off/truncation part 1160 in.Output have expected range and the expectation bit number LLR Λ ' (n).

The example of the method for normalizing of use table 4 is as follows.

This example is used for being difficult to estimate the situation of noise variable accurately in IEEE 802.16e system.Used such fact: the code in same modulation scheme during same-code speed has 1% FER when essentially identical SNR.In each modulation scheme, calculating FER is 1% o'clock SNR, and the norm_index that wherein reflects virtual (virtual) noise index is provided.IEEE 802.16e system has for the following modulation code of having used the burst of convolution turbo coded data.In this embodiment, norm_index_basic is used for actual norm_index.Table 5 shows the normalized example of IEEE 802.16e when implementing the structure of Fig. 8.

Table 5

The FEC type of code	Modulation system	Code rate	Gain	Norm_index_basic
						0	QPSK	1/ 2	2.0	11
1	QPSK	3/ 4	6.0	8
					2	16QAM	1/ 2	3.0	10
3	16QAM	3/ 4	8.0	7
					4	64QAM	1/ 2	8.0	7

5	64QAM	2/3	12.0	6
					6	64QAM	3/ 4	16.0	5
7	64QAM	5/6	24.0	4

In table 5, norm_index_basic is used for reflecting that the burst that IEEE 802.16e system defines increases (boosting) or zone increase.In the burst power control concept, the increase of the IEEE 802.16e support-12dB of system～9dB.When frequency re-use factor is 1/3, support the zone of 4.77dB to increase.In this case, because therefore the influence that the LLR value is increased need compensate feasible effective working region that can reduce LLR to it.For example, can utilize following equation to calculate norm_index.

......(13)

In equation (13), increasing unit is dB, and [a] expression is rounded to immediate integer.In addition, norm_index has the value in given range [0 24] scope.Use the method, more generally LLR normalization is possible.

Above-mentioned implementation method of the present invention is to use normalization coefficient and AMC information to come the example of the method for the normalization LLR corresponding with the tolerance that is input to decoder.The present invention uses normalization to the output of the soft output generator that serves as de-mapping device, and comprises and use normalized all execution modes of AMC information and executing.

Figure 12 and 13 shows under the situation of using the soft input tolerance of 6 or 8 bits and under the situation of execution floating-point operation, the performance of the convolution turbo sign indicating number that defines in the IEEE 802.16e system.The Turbo decoder uses max log MAP method.As can be seen, basic nonexistence can be poor between exemplary embodiment of the present invention for the normalization LLR of use 6 or 8 bits (by " decline, 6 bits " or " AWGN; 6 bits " and " decline; 8 bits " expression) and floating-point operation (being represented by " decline, Ft " and " AWGN, Ft ").

As can be known, the exemplary embodiment of specific embodiment of the present invention has following effect from top description.

According to one exemplary embodiment of the present invention, in wireless communication system, by the soft output of normalization from de-mapping device, channel all has different value in each symbol.Equally under the situation of the ofdm system of the higher tolerance resolution of needs, the performance of utilizing a small amount of bit of being input to the turbo decoder to obtain to expect.

Although one exemplary embodiment of the present invention is disclosed for illustrative purposes, it will be appreciated by those skilled in the art that without departing from the scope of the invention, can carry out various modifications, increase and replacement.Therefore, the invention is not restricted to the foregoing description, but limit by the four corner of appended claims and equivalent.

Claims (28)

1, a kind of in wireless communication system normalization be input to the device of the soft metric of channel decoder, comprising:

De-mapping device is used to produce soft metric; And

The normalization device, be used to receive this soft metric, calculate normalized log likelihood ratio LLR by ratio, should transform to a scope and a bit number by normalized LLR this soft metric multiplication by constants value and noise variate-value, and the input LLR of delivery channel decoder.

2, device as claimed in claim 1, wherein, this de-mapping device uses the modulation symbol R that receives _kIn-phase component X _kWith quadrature component Y _kIn at least one, channel fading coefficient g _kProduce soft metric with constant value c by the definition of the modulation order of the modulation symbol that receives.

3, device as claimed in claim 1, wherein, this normalization device is by multiply by this soft metric Carry out normalization, wherein σ _n ²It is the noise variate-value that calculates by the channel estimation of the modulation symbol that receives.

4, device as claimed in claim 3, wherein, this soft metric is produced by following table:

I _kCondition Λ(s _k，3) Λ(s _k，2) I _k＞2a _k 2I _k-2a _k 2a _k-I _k 0＜I _k≤2a _k I _k 2a _k-I _k -2a _k＜I _k≤0 I _k I _k+2a _k I _k≤-2a _k 2I _k+2a _k I _k+2a _k

With

Q _kCondition Λ(s _k，1) Λ(s _k，0) Q _k＞2a _k 2Q _k-2a _k 2a _k-Q _k 0＜Q _k≤2a _k 2Q _k-2a _k 2a _k-Q _k -2a _k＜Q _k≤0 Q _k Q _k+2a _k Q _k≤-2a _k 2Q _k+2a _k Q _k+2a _k

, wherein, I _k, Q _kAnd a _kBe respectively | g _k| ²X _k, | g _k| ²Y _kWith | g _k| ²C.

5, device as claimed in claim 1, wherein, this normalization device comprises:

Map table is used to receive the noise variate-value that is calculated by the channel estimation of the modulation symbol that receives, and the ratio of output constant value and noise variate-value;

Multiplier is used to export the normalization LLR by obtaining from the ratio of the soft metric multiplication by constants value of de-mapping device output and noise variate-value; And

Round off/truncation part, be used to export by normalized LLR being transformed to the input LLR of the channel decoder that this scope and this bit number obtain.

6, device as claimed in claim 2, wherein, this normalization device comprises:

Normalization index calculation device, be used to receive the noise variate-value that calculates by the channel estimation of the modulation symbol that receives, selection is mapped to the interim normalization index divided by this noise variate-value, and produces the normalization index by the predetermined value that deducts from selected interim normalization index according to the modulation order;

The normalization table is used for this normalization index is transformed to by this normalization index be multiply by the normalized gain value that normalization coefficient calculates;

Shift unit is used for the in-phase component and the quadrature component of the modulation symbol that displacement receives according to this normalized gain value;

Adder is used to export the normalization LLR that obtains by the value addition after will being shifted; And

Round off/truncation part, be used to export by normalized LLR being transformed to the input LLR of the channel decoder that this scope and this bit number obtain.

7, a kind of in wireless communication system normalization be input to the device of the soft metric of channel decoder, comprising:

De-mapping device is used to produce soft metric; And

The normalization device, be used to receive this soft metric, calculate normalized log likelihood ratio LLR by the normalization coefficient that this soft metric be multiply by by adaptive modulation and coding AMC information calculations, this normalized LLR is transformed to the scope of expectation and expects bit number, and the input LLR of delivery channel decoder.

8, device as claimed in claim 7, wherein, this de-mapping device uses the modulation symbol R that receives _kIn-phase component X _kWith quadrature component Y _kIn at least one, channel fading coefficient g _kProduce soft metric with constant value c by the definition of the modulation order of the modulation symbol that receives.

9, device as claimed in claim 7, wherein, this normalization device is carried out normalization by this soft metric be multiply by this normalization coefficient, and this normalization coefficient is that the normalization index by this AMC information calculations is provided with.

10, device as claimed in claim 9, wherein, this soft metric is produced by following table:

I _kCondition Λ(s _k，3) Λ(s _k，2) I _k＞2a _k 2I _k-2a _k 2a _k-I _k 0＜I _k≤2a _k I _k 2a _k-I _k -2a _k＜I _k≤0 I _k I _k+2a _k

I _k≤-2a _k 2I _k+2a _k I _k+2a _k

With

I _kCondition Λ(s _k，5) Λ(s _k，4) Λ(s _k，3) I _k＞6a _k 4I _k-12a _k 10a _k-2I _k 6a _k-I _k 4a _k＜I _k≤6a _k 3I _k-6a _k 4a _k-I _k 6a _k-I _k 2a _k＜I _k≤4a _k 2I _k-2a _k 4a _k-I _k I _k-2a _k 0＜I _k≤-2a _k I _k 6a _k-2I _k I _k-2a _k -2a _k＜I _k≤0 I _k 6a _k+2I _k -I _k-2a _k -4a _k＜I _k≤-2a _k 2I _k+2a _k 4a _k+I _k -I _k-2a _k -6a _k＜I _k≤-4a _k 3I _k+6a _k 4a _k+I _k 6a _k+I _k I _k≤-6a _k 4I _k+12a _k 10a _k+2I _k 6a _k+I _k

, wherein, I _k, Q _kAnd a _kBe respectively | g _k| ²X _k, | g _k| ²Y _kWith | g _k| ²C.

11, device as claimed in claim 7, wherein, this normalization device comprises:

The noise argument table is used for according at least one being provided with and exporting this noise variate-value and constant value many information of importing from the reception controller of the storage AMC information and the information of increase;

Map table is used to receive this noise variate-value and this constant value, and the ratio of output constant value and noise variate-value;

Multiplier is used to export the normalization LLR by obtaining from the ratio of the soft metric multiplication by constants value of de-mapping device output and noise variate-value; And

Round off/truncation part, be used to export by normalized LLR being transformed to the input LLR of the channel decoder that this scope and this bit number obtain.

12, device as claimed in claim 7, wherein, this normalization device comprises:

Normalization index calculation device is used for according at least one producing the normalization index that wherein reflects this noise variate-value and constant value many information of importing from the reception controller of the storage AMC information and the information of increase;

The normalization table is used to be provided with the normalization coefficient that is mapped to this normalization index;

Multiplier is used to export by multiply by the normalization LLR that set normalization coefficient obtains from the soft metric of this de-mapping device output; And

Round off/truncation part, be used to export by normalized LLR being transformed to the input LLR of the channel decoder that this scope and this bit number obtain.

13, device as claimed in claim 7, wherein, this normalization device comprises:

Normalization index calculation device is used for according at least one producing the normalization index that wherein reflects this noise variate-value and constant value many information of importing from the reception controller of the storage AMC information and the information of increase;

The normalization table is used for this normalization index is transformed to by this normalization index be multiply by the normalized gain value that normalization coefficient calculates;

Shift unit is used for the in-phase component and the quadrature component of the modulation symbol that displacement receives according to this normalized gain value;

Adder is used to export the normalization LLR that obtains by the value addition after will being shifted; And

Round off/truncation part, be used to export by normalized LLR being transformed to the input LLR of the channel decoder that this scope and this bit number obtain.

14, device as claimed in claim 7, wherein, this AMC information comprises at least one in modulation order time, code rate and the frame size.

15, a kind of in wireless communication system normalization be input to the method for the soft metric of channel decoder, comprising:

Produce soft metric;

Receive this soft metric, and calculate normalized log likelihood ratio LLR by ratio with this soft metric multiplication by constants value and noise variate-value;

Should transform to a scope and a bit number by normalized LLR; And

The input LLR of delivery channel decoder.

16, method as claimed in claim 15, wherein, the step of described generation soft metric comprises uses the modulation symbol R that receives _kIn-phase component X _kWith quadrature component Y _k, channel fading coefficient g _kProduce soft metric with constant value c by the definition of the modulation order of the modulation symbol that receives.

17, method as claimed in claim 15, wherein, by this soft metric be multiply by

Calculate normalized LLR, wherein σ _n ²It is the noise variate-value that calculates by the channel estimation of the modulation symbol that receives.

18, method as claimed in claim 17, wherein, the step of described generation soft metric comprises by following table and produces soft metric:

I _kCondition Λ(s _k，3) Λ(s _k，2) I _k＞2a _k 2I _k-2a _k 2a _k-I _k 0＜I _k≤2a _k I _k 2a _k-I _k -2a _k＜I _k≤0 I _k I _k+2a _k I _k≤-2a _k 2I _k+2a _k I _k+2a _k

With

I _kCondition Λ(s _k，5) Λ(s _k，4) Λ(s _k，3) I _k＞6a _k 4I _k-12a _k 10a _k-2I _k 6a _k-I _k 4a _k＜I _k≤6a _k 3I _k-6a _k 4a _k-I _k 6a _k-I _k 2a _k＜I _k≤4a _k 2I _k-2a _k 4a _k-I _k I _k-2a _k 0＜I _k≤-2a _k I _k 6a _k-2I _k I _k-2a _k -2a _k＜I _k≤0 I _k 6a _k+2I _k -I _k-2a _k -4a _k＜I _k≤-2a _k 2I _k+2a _k 4a _k+I _k -I _k-2a _k -6a _k＜I _k≤-4a _k 3I _k+6a _k 4a _k+I _k 6a _k+I _k I _k≤-6a _k 4I _k+12a _k 10a _k+2I _k 6a _k+I _k

, wherein, I _k, Q _kAnd a _kBe respectively | g _k| ²X _k, | g _k| ²Y _kWith | g _k| ²C.

19, method as claimed in claim 15, wherein, the step of the input LLR of described delivery channel decoder comprises:

The noise variate-value that reception is calculated by the channel estimation of the modulation symbol that receives, and the ratio of output constant value and noise variate-value;

The normalization LLR that output obtains by the ratio with this soft metric multiplication by constants value and noise variate-value; And

Output is by the input LLR of the channel decoder that normalized LLR transformed to this scope and this bit number and obtain.

20, method as claimed in claim 15, wherein, the step of the input LLR of described delivery channel decoder comprises:

The noise variate-value that reception is calculated by the channel estimation of the modulation symbol that receives, and selection is mapped to the interim normalization index divided by this noise variate-value;

Produce the normalization index by the value that from selected interim normalization index, deducts according to the modulation order;

This normalization index is transformed to by this normalization index be multiply by the normalized gain value that normalization coefficient calculates;

The in-phase component and the quadrature component of the modulation symbol that displacement receives according to this normalized gain value;

The normalization LLR that output obtains by the value addition after will being shifted; And

Output is by the input LLR of the channel decoder that normalized LLR transformed to this scope and this bit number and obtain.

21, a kind of in wireless communication system normalization be input to the method for the soft metric of channel decoder, comprising:

Produce soft metric;

Receive this soft metric, and calculate normalized log likelihood ratio LLR by the normalization coefficient that this soft metric be multiply by by adaptive modulation and coding AMC information calculations; And

Should transform to a scope and a bit number by normalized LLR, and the input LLR of delivery channel decoder.

22, method as claimed in claim 21, wherein, the step of described generation soft metric comprises uses the modulation symbol R that receives _kIn-phase component X _kWith quadrature component Y _k, channel fading coefficient g _kProduce soft metric with constant value c by the definition of the modulation order of the modulation symbol that receives.

23, method as claimed in claim 21, wherein, by this soft metric be multiply by

Calculate normalized LLR, wherein σ _n ²It is the noise variate-value that calculates by the channel estimation of the modulation symbol that receives.

24, method as claimed in claim 23, wherein, the step of described generation soft metric comprises by following table and produces soft metric:

I _kCondition Λ(s _k，3) Λ(s _k，2) I _k＞2a _k 2I _k-2a _k 2a _k-I _k 0＜I _k≤2a _k I _k 2a _k-I _k -2a _k＜I _k≤0 I _k I _k+2a _k I _k≤-2a _k 2I _k+2a _k I _k+2a _k

With

I _kCondition Λ(s _k，5) Λ(s _k，4) Λ(s _k，3) I _k＞6a _k 4I _k-12a _k 10a _k-2I _k 6a _k-I _k 4a _k＜I _k≤6a _k 3I _k-6a _k 4a _k-I _k 6a _k-I _k

2a _k＜I _k≤4a _k 2I _k-2a _k 4a _k-I _k I _k-2a _k 0＜I _k≤-2a _k I _k 6a _k-2I _k I _k-2a _k -2a _k＜I _k≤0 I _k 6a _k+2I _k -I _k-2a _k -4a _k＜I _k≤-2a _k 2I _k+2a _k 4a _k+I _k -I _k-2a _k -6a _k＜I _k≤-4a _k 3I _k+6a _k 4a _k+I _k 6a _k+I _k I _k≤-6a _k 4I _k+12a _k 10a _k+2I _k 6a _k+I _k

, wherein, I _k, Q _kAnd a _kBe respectively | g _k| ²X _k, | g _k| ²Y _kWith | g _k| ²C.

25, method as claimed in claim 21, wherein, the step of the input LLR of described delivery channel decoder comprises:

According at least one in many information of from the reception controller of the storage AMC information and the information of increase, importing this noise variate-value and constant value is set;

Receive this noise variate-value and this constant value, and the ratio of output constant value and noise variate-value;

The normalization LLR that output obtains by the ratio with this soft metric multiplication by constants value and noise variate-value; And

Output is by the input LLR of the channel decoder that normalized LLR transformed to this scope and this bit number and obtain.

26, method as claimed in claim 21, wherein, the step of the input LLR of described delivery channel decoder comprises:

Produce the normalization index that wherein reflects this noise variate-value and constant value according at least one in many information of from the reception controller of the storage AMC information and the information of increase, importing;

Setting is mapped to the normalization coefficient of this normalization index;

Output is by multiply by this soft metric the normalization LLR that set normalization coefficient obtains; And

Output is by the input LLR of the channel decoder that normalized LLR transformed to this scope and this bit number and obtain.

27, method as claimed in claim 21, wherein, the step of the input LLR of described delivery channel decoder comprises:

Produce the normalization index that wherein reflects this noise variate-value and constant value according at least one in many information of from the reception controller of the storage AMC information and the information of increase, importing;

This normalization index is transformed to by this normalization index be multiply by the normalized gain value that normalization coefficient calculates;

The in-phase component and the quadrature component of the modulation symbol that displacement receives according to this normalized gain value;

The normalization LLR that output obtains by the value addition after will being shifted; And

Output is by the input LLR of the channel decoder that normalized LLR transformed to this scope and this bit number and obtain.

28, method as claimed in claim 21, wherein, this AMC information comprises at least one in modulation order time, code rate and the frame size.

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