CN101305575B - 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 QPSK (QPSK), 8PSK, 16 quadrature amplitude modulation (16-QAM), 64 quadrature amplitude modulation modulation systems such as (64-QAM).In addition, the channel code of these systems incorporate such as the turbo code carried out adaptive modulation and coding (AMC).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 implements 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 the 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 through 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.Be imported in the channel decoder 180 with the corresponding sequence Λ (n) of metric that in de-mapping device 170, calculates, and be decoded into the binary data of original transmission.When channel decoder 180 was accomplished decode operation, receiver 150 was accomplished 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 stated, 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 receives the influence of quantizing noise, clipped noise or the like.Therefore, each step of communication system all should be operated through the normalization that execution is suitable for measuring representation and guaranteed that optimum performance has minimal hardware simultaneously.But because the normalization of the tolerance that conventional method is not considered in de-mapping device, to calculate, 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 when channel-decoding, utilizes small number of bits in a kind of wireless communication system can obtain the method and apparatus of optimum performance.

In addition, example embodiment of the present invention provides a kind of and in wireless communication system, utilizes small number of bits can improve the method and apparatus of decoding performance through normalization as the tolerance of the input of channel decoder.

In addition, example 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, example 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; Ratio through this soft metric being multiply by this constant value and noise variate-value comes calculating normalization log-likelihood ratio (LLR), and this normalized LLR is transformed to the bit number of desired range and 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; Normalization coefficient through this soft metric being multiply by by adaptive modulation and coding (AMC) information calculations comes calculating normalization log-likelihood ratio (LLR); This normalized LLR is transformed to the bit number of desired range and 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 come calculating normalization log-likelihood ratio (LLR) through the ratio that this soft metric multiply by this constant value and noise variate-value; And the bit number that will this normalized LLR transforms to desired range and 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 come calculating normalization log-likelihood ratio (LLR) through the normalization coefficient that this soft metric multiply by by adaptive modulation and coding (AMC) information calculations; And the bit number that will this normalized LLR transforms to desired range and expectation, and the input LLR of delivery channel decoder.

Description of drawings

Through 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, characteristic 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 example embodiment of the present invention the structure of the transceiver of input tolerance normalization device;

Fig. 3 A shows QPSK (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 example embodiment of the present invention;

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

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

Fig. 8 has shown according to the application of second example 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 example embodiment of the present invention;

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

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

Embodiment

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

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

< first example embodiment >

First example 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 example 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 through 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 example 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 accomplished base band demodulating, symbol that receives and channel estimation are 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 through quadrature amplitude modulation (QAM) or phase shift keying (PSK), and exports the tolerance of every bit through 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 send the modulation back 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 QPSK (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 equality, from m binary character shown in equality (1), can obtain the homophase and the quadrature component of modulation symbol.

In equality (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.

Can find out the x of symbol that will be modulated from Fig. 3 A to 3C _kBy s _{K, m-1}, s _{K, m-2}..., s _{K, m/2}Confirm, and yk is by s _{K, m/2,1}..., s _{K, 0}Confirm.The constant c that can confirm each constellation point is defined by equality (2).This is that the average energy that is used for symbol is set to 1 value.

${\mathrm{<figure-callout\; id="4"\; label="c"\; filenames="S2006800421146E00081.png,S2006800421146E00141.png"\; state="\{\{state\}\}">c</figure-callout>}}_4=\frac{1}{\sqrt{2}}=0.70711$

${\mathrm{<figure-callout\; id="16"\; label="c"\; filenames="S2006800421146E00051.png,S2006800421146E00131.png"\; state="\{\{state\}\}">c</figure-callout>}}_{16}=\frac{1}{\sqrt{10}}=0.3162$

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

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 equality (3) is input in the de-mapping device 270.

R _k＝g _k(x _k+jy _k)+n _xk+jn _yk

＝X _k+jY _k......(3)

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 equality (4).

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

$=\log \frac{\underset{z_k}{\mathrm{\&Sigma;}}\exp \left\{\frac{-1}{{\mathrm{\&sigma;}}_{\mathrm{<figure-callout\; id="2"\; label="n"\; filenames="S2006800421146E00081.png,S2006800421146E00141.png"\; state="\{\{state\}\}">n</figure-callout>}}^2}{|R_k-z_k(s_{k,i}=0)|}^2\right\}}{\underset{z_k}{\mathrm{\&Sigma;}}\exp \left\{\frac{-1}{{\mathrm{\&sigma;}}_{\mathrm{<figure-callout\; id="2"\; label="n"\; filenames="S2006800421146E00081.png,S2006800421146E00141.png"\; state="\{\{state\}\}">n</figure-callout>}}^2}{|R_k-z_k(s_{k,i}=1)|}^2\right\}}$

$\&ap;\log \frac{\exp \left\{\frac{-1}{{\mathrm{\&sigma;}}_{\mathrm{<figure-callout\; id="2"\; label="n"\; filenames="S2006800421146E00081.png,S2006800421146E00141.png"\; state="\{\{state\}\}">n</figure-callout>}}^2}\min {|R_k-z_k(s_{k,i}=0)|}^2\right\}}{\exp \left\{\frac{-1}{{\mathrm{\&sigma;}}_{\mathrm{<figure-callout\; id="2"\; label="n"\; filenames="S2006800421146E00081.png,S2006800421146E00141.png"\; state="\{\{state\}\}">n</figure-callout>}}^2}\min {|R_k-z_k(s_{k,i}=1)|}^2\right\}}$

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

......(4)

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 equality (4), use logarithm maximum a posteriori probability (MAP) scheme and calculate LLR, use low computational effort can obtain highly reliable estimation.Equality (4) can be similar to shown in equality (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 equality (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 equality as shown in Figure 4 (6) ₃LLR.

$\widetilde{\mathrm{\&Lambda;}}\left(s_{k,3}\right)=\frac{1}{{\mathrm{\&sigma;}}_n^2}(-1)[{|X_k-3{\mathrm{<figure-callout\; id="16"\; label="g\; k\; c"\; filenames="S2006800421146E00051.png,S2006800421146E00131.png"\; state="\{\{state\}\}">g</figure-callout>}}_k{c}_{}{}_{16}|}^2-{\left|{X_k+{\mathrm{<figure-callout\; id="16"\; label="g\; k\; c"\; filenames="S2006800421146E00051.png,S2006800421146E00131.png"\; state="\{\{state\}\}">g</figure-callout>}}_{k}c}_{16}\right|}^2]$

$=\frac{{4\mathrm{<figure-callout\; id="16"\; label="c"\; filenames="S2006800421146E00051.png,S2006800421146E00131.png"\; state="\{\{state\}\}">c</figure-callout>}}_{16}}{{\mathrm{\&sigma;}}_n^2}(2{\left|g_k\right|}^2{X}_k-2{\left|g_k\right|}^2{c}_{16})$

......(6)

When the method for use shown in equality (6) calculated LLR, all having the part in coefficient

and the bracket under every kind of situation was 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 through estimating that from LLR the function that coefficient

produces soft metric is SMG (a; B), the equality (6) that then is used to calculate LLR can be rewritten as equality (7).

$\widetilde{\mathrm{\&Lambda;}}\left(s_{k,i}\right)=\frac{4c}{{\mathrm{\&sigma;}}_{\mathrm{<figure-callout\; id="2"\; label="n"\; filenames="S2006800421146E00081.png,S2006800421146E00141.png"\; state="\{\{state\}\}">n</figure-callout>}}^2}{\mathrm{SMG}}_i({{\left|g_k\right|}^{2}X}_k,{\left|g_k\right|}^{2}c)$

$=\frac{4c}{{\mathrm{\&sigma;}}_{\mathrm{<figure-callout\; id="2"\; label="n"\; filenames="S2006800421146E00081.png,S2006800421146E00141.png"\; state="\{\{state\}\}">n</figure-callout>}}^2}\mathrm{\&Lambda;}\left(s_{k,i}\right)$ ......(7)

Equality (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 equality (8).

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

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

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

......(8)

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

In the coefficient between the output that is attached to SMG jointly

; Value 4 is QPSK; The common coefficient of 16QAM and 64QAM, therefore reflection quantizes.

is set thereby makes 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 equality (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.

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

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

Here, a _kFor | g _k| ²C.Equality (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 equality (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)	A(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 calculate through removing

from the equality (7) of the original input LLR that is used for expressing decoder.

In the exemplary hardware execution mode, the extra increase of dynamic range possibility of the input of decoder tolerance, perhaps its performance possibly degenerated.Therefore,

is reflected in the normalization.

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

Fig. 5 shows the example of the tolerance normalization device of the value that is used for reflection

.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.Need noise variable estimation device (as indicated) in order to calculate the noise variable corresponding with the summation variable of interference

by the reference number 265 of Fig. 2 with noise.Noise variable estimation device 265 can use various algorithm estimated noise variate-values

In normalization device 275; Multiplier 520 receives

that the map table 510 through using the reflection division calculates the variate-value conversion when multiplier 520 will multiply by

from the tolerance Λ (n) of de-mapping device 270, normalization LLR.After normalization LLR, round off/truncation part 530 will have expected range with 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 through 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 example 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, with the example of describing method for normalizing in detail.This normalization index calculation device 610 has the temp_norm_index that is mapped to the estimated value that can from noise variable estimation device 265, receive.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 $\left[(\mathrm{Temp}\_\mathrm{Norm}\_\mathrm{Index})\left(\mathrm{DB}\right)\right]+\left[{\mathrm{\&sigma;}}_n^2\left(\mathrm{DB}\right)\right]+a=0.$ 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 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, possibly regulate the LLR normalization of about 3dB.Only when can regulating more accurately and 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, through 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 with truncation part 660 output expected range with 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 in the channel decoder of the system that uses QPSK, 16QAM and 64QAM, to implement normalized example.Certainly, the present invention includes all possible method of using noise estimation and the output LLR of the SMG of modulation order.

< second example embodiment >

Exist to be difficult to calculate in the communication system situation of noise variate-value accurately, this is different from first example 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 FER 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 through 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 basically, 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.

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

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

${\widehat{\mathrm{\&sigma;}}}_{\mathrm{<figure-callout\; id="2"\; label="n"\; filenames="S2006800421146E00081.png,S2006800421146E00141.png"\; state="\{\{state\}\}">n</figure-callout>}}^2=\frac{\mathrm{<figure-callout\; id="10"\; label="P"\; filenames="S2006800421146E00032.png,S2006800421146E00051.png"\; state="\{\{state\}\}">P</figure-callout>}}{{10}^{0.15}}......\left(12\right)$

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 example 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 receive almost independently decline.Compare 1% the FER that the system that when higher CINR, reaches is required 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 with 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 example 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 the time continuous wave in CDMA or the OFDM scheme according to this symbol, and the ripple that is produced is sent to receiver 850 through 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 through 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 the also 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 example 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 with the modulation order by the predetermined noise level of AMC information.

In normalization device 875, multiplier 930 receives the c/ σ that the map table 920 through 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 with 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 example 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 with 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 example embodiment of the present invention.

Figure 11 shows the structure that obtains through 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, possibly regulate the LLR normalization of about 3dB.Only when can regulating more accurately and 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, through 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 with the expectation bit number LLR Λ ' (n).

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

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

[0145]?

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 equality to calculate norm_index.

In equality (13), increasing unit is dB, and [a] expression is rounded to immediate integer.In addition, norm_index has the value in given range [024] scope.Use the method, more general 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.Can find out that 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 ").

Can know that from top description the exemplary embodiment of specific embodiment of the present invention has following effect.

According to example embodiment of the present invention, in wireless communication system, through 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 the small number of bits that is input to the turbo decoder to obtain to expect.

Although example 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 the four corner of appended claims and equivalent.

Claims (20)

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

   De-mapping device is used to use k the modulation symbol R that receives _kIn-phase component X _kWith quadrature component Y _kIn at least one, channel fading coefficient g _kProduce the soft metric of every bit of the modulation symbol of reception with constant value c by the definition of the modulation order of the modulation symbol that receives, wherein k is a natural number; And

   The normalization device; Be used to receive this soft metric; Come calculating normalization log-likelihood ratio LLR through this soft metric being multiply by

   

   ; Should transform to a bit number by normalized LLR; And the LLR of output transform is as the input LLR of channel decoder, and wherein is the noise variate-value that is calculated by the channel estimation of the modulation symbol that receives.
2. 2. device as claimed in claim 1, wherein, this soft metric Λ () 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, s _{K, i}(i=0,1 ..., m-1) being i the symbol of output sequence that is mapped to the binary channel encoder of k signaling point, m is the bit number of a modulation symbol that is used for representing the output sequence of binary channel encoder.
3. 3. 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 received modulation symbol, and the ratio of output constant value and noise variate-value;

   Multiplier is used to export the normalization LLR through 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 through normalized LLR being transformed to the input LLR of the channel decoder that this bit number obtains.
4. 4. device as claimed in claim 1, 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 through the predetermined value that from selected interim normalization index, deducts according to the modulation order;

   The normalization table is used for this normalization index is transformed to through this normalization index 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 through the value addition after will being shifted; And

   Round off/truncation part, be used to export through normalized LLR being transformed to the input LLR of the channel decoder that this bit number obtains.
5. One kind in wireless communication system normalization be input to the device of the soft metric of channel decoder, comprising:

   De-mapping device is used to use k the modulation symbol R that receives _kIn-phase component X _kWith quadrature component Y _kIn at least one, channel fading coefficient g _kProduce the soft metric of every bit of the modulation symbol of reception with constant value c by the definition of the modulation order of the modulation symbol that receives, wherein k is a natural number; And

   The normalization device; Be used to receive this soft metric; Normalization coefficient through this soft metric being multiply by by the normalization index setting of adaptive modulation and coding AMC information calculations comes calculating normalization log-likelihood ratio LLR; Should transform to a bit number by normalized LLR, and the LLR of output transform is as the input LLR of channel decoder.
6. 6. device as claimed in claim 5, wherein, this soft metric Λ () 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

   Or

   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, s _{K, i}(i=0,1 ..., m-1) being i the symbol of output sequence that is mapped to the binary channel encoder of k signaling point, m is the bit number of a modulation symbol that is used for representing the output sequence of binary channel encoder.
7. 7. device as claimed in claim 5, wherein, this normalization device comprises:

   The noise argument table, be used for according to increase from storage AMC information and burst or many information that the reception controller of regional increase information is imported at least one be provided with and output noise variate-value and constant value;

   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 through 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 through normalized LLR being transformed to the input LLR of the channel decoder that this bit number obtains.
8. 8. device as claimed in claim 5, wherein, this normalization device comprises:

   Normalization index calculation device, be used for based on increase from storage AMC information and burst or many information that the reception controller of regional increase information is imported at least one produce the normalization index that wherein reflects noise variate-value and constant value;

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

   Multiplier is used to export through 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 through normalized LLR being transformed to the input LLR of the channel decoder that this bit number obtains.
9. 9. device as claimed in claim 5, wherein, this normalization device comprises:

   Normalization index calculation device, be used for based on increase from storage AMC information and burst or many information that the reception controller of regional increase information is imported at least one produce the normalization index that wherein reflects noise variate-value and constant value;

   The normalization table is used for this normalization index is transformed to through this normalization index 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 through the value addition after will being shifted; And

   Round off/truncation part, be used to export through normalized LLR being transformed to the input LLR of the channel decoder that this bit number obtains.
10. 10. device as claimed in claim 5, wherein, this AMC information comprises at least one in modulation order time, code rate and the frame size.
11. 11. one kind in wireless communication system normalization be input to the method for the soft metric of channel decoder, comprising:

    K the modulation symbol R that use receives _kIn-phase component X _kWith quadrature component Y _k, channel fading coefficient g _kProduce the soft metric of every bit of the modulation symbol of reception with constant value c by the definition of the modulation order of the modulation symbol that receives, wherein k is a natural number;

    Receive this soft metric; And come calculating normalization log-likelihood ratio LLR through this soft metric being multiply by

    

    , wherein

    

    is the noise variate-value that is calculated by the channel estimation of the modulation symbol that receives;

    Should transform to a bit number by normalized LLR; And

    The LLR of output transform is as the input LLR of channel decoder.
12. 12. method as claimed in claim 11, wherein, the step of said generation soft metric Λ () 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

    Or

    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, s _{K, i}(i=0,1 ..., m-1) being i the symbol of output sequence that is mapped to the binary channel encoder of k signaling point, m is the bit number of a modulation symbol that is used for representing the output sequence of binary channel encoder.
13. 13. method as claimed in claim 11, wherein, the step of the normalized LLR of said output 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; With

    The normalization LLR that output obtains through the ratio with this soft metric multiplication by constants value and noise variate-value.
14. 14. method as claimed in claim 11, wherein, the step of the input LLR of said delivery channel decoder comprises:

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

    Value through from selected interim normalization index, deducting based on the modulation order produces the normalization index;

    This normalization index is transformed to through this normalization index 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 based on this normalized gain value;

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

    Output is through the input LLR of the channel decoder that normalized LLR transformed to this bit number and obtain.
15. 15. one kind in wireless communication system normalization be input to the method for the soft metric of channel decoder, comprising:

    K the modulation symbol R that use receives _kIn-phase component X _kWith quadrature component Y _k, channel fading coefficient g _kProduce the soft metric of every bit of the modulation symbol of reception with constant value c by the definition of the modulation order of the modulation symbol that receives, wherein k is a natural number;

    Receive this soft metric, and come calculating normalization log-likelihood ratio LLR through the normalization coefficient that this soft metric multiply by by the normalization index setting of adaptive modulation and coding AMC information calculations; And

    Should transform to a bit number by normalized LLR, and the LLR of output transform is as the input LLR of channel decoder.
16. 16. method as claimed in claim 15, wherein, the step of said generation soft metric Λ () 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

    Or

    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, s _{K, i}(i=0,1 ..., m-1) being i the symbol of output sequence that is mapped to the binary channel encoder of k signaling point, m is the bit number of a modulation symbol that is used for representing the output sequence of binary channel encoder.
17. 17. method as claimed in claim 15, wherein, the step of the input LLR of said delivery channel decoder comprises:

    According at least one in many information of from the reception controller of storage AMC information and burst increase or regional increase information, importing noise variate-value and constant value are 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 through the ratio with this soft metric multiplication by constants value and noise variate-value; And

    Output is through the input LLR of the channel decoder that normalized LLR transformed to this bit number and obtain.
18. 18. method as claimed in claim 15, wherein, the step of the input LLR of said delivery channel decoder comprises:

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

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

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

    Output is through the input LLR of the channel decoder that normalized LLR transformed to this bit number and obtain.
19. 19. method as claimed in claim 15, wherein, the step of the input LLR of said delivery channel decoder comprises:

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

    This normalization index is transformed to through this normalization index 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 based on this normalized gain value;

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

    Output is through the input LLR of the channel decoder that normalized LLR transformed to this bit number and obtain.
20. 20. method as claimed in claim 15, wherein, this AMC information comprises at least one in modulation order time, code rate and the frame size.

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