CN101127544A - SIR identification method for eliminating multi-path interference - Google Patents

Abstract

The utility model provides a signal-to-interference ratio determination method for eliminating multi-path interferences, which comprises the following steps: determining the average interference noise of each path of user terminal signals and the signal energy in a certain time slot according to the average interference noise; determining Beta value; determining and removing the multi-path interference energy, and also determining the external interference energy according to the signal energy and Beta value; determining the signal-to-interference ratio according to signal energy and external interference energy. The utility model has the advantages that: by eliminating the multi-path interference, the SIR estimation performance can be drastically improved, and power control failures and imprecise calculation of UE load due to inaccurate SIR estimation can be effectively avoided.

Description

Eliminate the signal interference ratio of multipath interference and determine method

Technical field

The present invention relates to field of wireless communication, more specifically, relate to a kind of signal interference ratio of eliminating the multipath interference and determine method.

Background technology

In code division multiple access (CDMA) system, the accuracy of inner loop power control depends on the accuracy that signal interference ratio (SIR) is estimated.

Wideband Code Division Multiple Access (WCDMA) (WCDMA) system that organizes to set up with 3GPP is an example, and in the business of R99 and R5 version, because up spreading gain is bigger, the required power of up channel demodulation (that is, antenna opening receive power) is often less than the power of interference noise.The interference noise that a user (UE) signal is subjected to mainly be by the end make an uproar and other sub-district in other user's interference cause that the interference between many footpaths of this UE signal itself is not in the highest flight.Therefore, the SIR algorithm for estimating in R99 and R5 as described below.

If the frequency pilot sign Pilot of the s time slot in the footpath of the p bar after the depolarization _{P, s}(k) always total Npilot the pilot tone of expression, each time slot, always total P bar multipath, then elder generation estimates the interference noise Inew of current time slots s _s, method of estimation normally averages the interference in each bar footpath.For example:

$\mathrm{Ine}{w}_s=\frac{1}{2*P*(\mathrm{Npilot}-1)}\underset{p=1}{\overset{p}{\mathrm{\Σ}}}\underset{k=1}{\overset{\mathrm{Npilot}-1}{\mathrm{\Σ}}}{\left|\right|\mathrm{Pilo}{t}_{p,s}\left(k\right)-\mathrm{Pilo}{t}_{p,s}(k-1)\left|\right|}^2---\left(b1\right)$

Carry out average (for example adopting IIR filtering) between time slot then, to obtain Noise Estimation.At last, interference noise I (s) estimated result of this slot s is:

I _s＝Alpha*I _s-1+(1-Alpha)*Inew _s (b2)

Wherein, Alpha can get more than 0.9, below 1.

For the estimation of signal energy, usually the energy accumulation in each bar footpath.For example, concrete computational methods can for:

$S_s=\frac{1}{\mathrm{<figure-callout\; id="2"\; label="Npilo\; t"\; filenames="A20071014535500161.png,A20071014535500171.png"\; state="\{\{state\}\}">Npilo</figure-callout>}{t}^{}{}^2}\underset{p=1}{\overset{p}{\mathrm{\&Sigma;}}}{\left|\right|\underset{k=1}{\overset{\mathrm{Npilot}}{\mathrm{\&Sigma;}}}\mathrm{Pilo}{t}_{p,s}\left(k\right)\left|\right|}^2-\frac{P}{\mathrm{Npilot}}{I}_s---\left(b3\right)$

So SIR of a time slot _sFor:

SIR _s＝S _s/I _s (b4)

With this SIR _sCompare with the desired value SIRtarget of signal interference ratio, just can determine to control power control (TPC) order of UE transmitting power.

In above-mentioned derivation, do not distinguish the phase mutual interference between each bar footpath of same UE, so only just approximate establishment under the interference I in each bar footpath prerequisite that other noise N is very little relatively.Yet, insert in (HSUPA) business, in order to support the high speed uplink business in the high speed uplink packet of R6 version, the power of a UE is bigger probably, even also bigger than interference noise N, each bar footpath phase mutual interference at this moment, the energy of interference is subjected to the multipath signal energy affect very big.

Fig. 1 is the schematic diagram of multipath signal phase mutual interference in the conventional method.

Energy distribution on the antenna as shown in Figure 1: interference noise N=1, article one, Jing energy is S1ant=2, the energy in second footpath is S2ant=3, then the actual value of SIR should be SF* (2+3)/Beta/1=5*SF/Beta, the SF here is the spreading factor of DPCCH, be 256 in the WCDMA system, Beta is the ratio of all physical channel gross powers of UE and DPCCH channel power.In demodulating process, the interference in article one footpath is I1ant=S2ant+N=4, and the interference in second footpath is I2ant=S1ant+N=3.This moment, interference ratio noise N was big, and the interference in two footpaths varies in size.With above-mentioned SIR algorithm for estimating, the measured value that obtains is that SIR=SF* (2+3)/Beta/ ((3+4)/2)=1.43*SF/Beta and actual value ratio differ greatly, and well below actual value.

Measured value well below the consequence that actual value brought is, real SIR has surpassed SIRtarget, but measured SIR is still less than SIRtarget, thereby send the TPC order that makes UE continue lifting power, reach SIRtarget up to measured SIR, thereby cause the transmitting power of UE too high, cause serious interference, worsen systematic function other UE.In addition, need to use SIR to calculate the load of UE in the R6 version, be used for the scheduling of HSUPA business.If it is on the low side that SIR calculates, the UE load is also on the low side, will cause the HSUPA scheduling performance to descend like this, also systematic function is caused deterioration.

This shows, at R99, among R5 and the R6 usually use do not consider that the SIR method of estimation of disturbing between multipath carries out power control, when signal energy is big, can bring bigger error, thus the severe exacerbation systematic function.

Summary of the invention

In order to solve above-mentioned the problems of the prior art, the present invention proposes a kind of signal interference ratio of eliminating the multipath interference and determine method, this method comprises: step 1, determine user terminal signal each bar footpath the average interference noise and according to the signal energy of average interference noise calculation signal at certain time slot; Step 2 is determined the Beta value; Step 3 according to signal energy and Beta value, is determined the multipath interfering energy of signal, removes the multipath interfering energy, and definite external disturbance energy; And step 4, determine signal interference ratio according to signal energy and external disturbance energy.

Signal interference ratio according to the present invention is determined method, and the average interference noise in each bar footpath is determined by following formula:

$\mathrm{Ine}{w}_s=\frac{1}{2*P*(\mathrm{Npilot}-1)}\underset{p=1}{\overset{P}{\mathrm{\&Sigma;}}}\underset{k=1}{\overset{\mathrm{Npilot}-1}{\mathrm{\&Sigma;}}}{\left|\right|\mathrm{Pilo}{t}_{p,s}\left(k\right)-\mathrm{Pilo}{t}_{p,s}(k-1)\left|\right|}^2$ , and

I _s＝Inew _s

Wherein, Pilot _p, the frequency pilot sign of the s time slot in p bar footpath on antenna of s (k) expression, Npilot represents the total number of the pilot tone of each time slot, and P represents the total number of multipath on this antenna, and s represents the s time slot, and I _sExpression average interference noise.

Further comprising the steps of in step 3:

It is average according to following formula the average interference noise to be carried out filtering in time, obtaining the average interference noise,

I _s＝AlphaI*I _s-1+(1-AlphaI)*Inew _s，

Wherein, AlphaI is more than or equal to 0 and smaller or equal to 1 coefficient, I _sIt is the average interference noise of s time slot.

Signal energy in the inventive method is determined by following formula:

$S_s=\frac{1}{\mathrm{<figure-callout\; id="2"\; label="Npilo\; t"\; filenames="A20071014535500161.png,A20071014535500171.png"\; state="\{\{state\}\}">Npilo</figure-callout>}{t}^{}{}^2}\underset{p=1}{\overset{P}{\mathrm{\&Sigma;}}}[{\left|\right|\underset{k=1}{\overset{\mathrm{Npilot}}{\mathrm{\&Sigma;}}}\mathrm{Pilo}{t}_{p,s}\left(k\right)\left|\right|}^2-\frac{P}{\mathrm{Npilot}}{I}_s],$

Wherein, S _sThe signal energy of representing the s time slot.

Simultaneously, the Beta value is determined by following formula:

$\mathrm{Beta}=\frac{S_s+\underset{i=2}{\overset{k}{\mathrm{\&Sigma;}}}[\underset{p=1}{\overset{P}{\mathrm{\&Sigma;}}}{A_{p,i}}^2-P*I_s*\mathrm{<figure-callout\; id="1"\; label="S\; F"\; filenames="A20071014535500161.png,A20071014535500171.png"\; state="\{\{state\}\}">S</figure-callout>}{F}_{}{}_1/S{F}_i]}{S_s},$

Wherein, K represents to have on the user terminal K bar uplink physical channel, A _{P, i}The signal averaging amplitude of the i bar physical channel of expression user terminal behind the descrambling and de-spreading of p bar footpath, and SF _iBe the employed spreading factor of descrambling and de-spreading, wherein, the spreading factor SF of DPCCH in the WCDMA system ₁Be 256.

Signal interference ratio according to the present invention is determined method, and the Beta value can also be determined by following formula:

$\mathrm{Beta}=\frac{\underset{i=1}{\overset{K}{\mathrm{\&Sigma;}}}{B_i}^2}{{{\mathrm{<figure-callout\; id="1"\; label="B"\; filenames="A20071014535500161.png,A20071014535500171.png"\; state="\{\{state\}\}">B</figure-callout>}}_1}^2}$

Wherein, Bi represents the emission amplitude adjustment factor of all up channel i, and B ₁For the amplitude of DPCCH is adjusted the factor.

In the present invention, the multipath interfering energy of signal is determined by following formula:

$\mathrm{Nne}{w}_s=I_s-\frac{P-1}{P}*\mathrm{Beta}*S_s/\mathrm{<figure-callout\; id="1"\; label="S\; F"\; filenames="A20071014535500161.png,A20071014535500171.png"\; state="\{\{state\}\}">S</figure-callout>}{F}_{}{}_1$

Wherein, Nnew _sThe multipath interfering energy of expression signal.

In step 3, the external disturbance energy is determined by following formula:

N _s＝AlphaN*N _s-1+(1-AlphaN)*Nnew _s

Wherein, AlphaI is more than or equal to 0 and smaller or equal to 1 coefficient, and N _sExpression external disturbance energy.

Thereby, adopt the present invention can estimate SIR exactly, thereby can carry out power control exactly.

Other features and advantages of the present invention will be set forth in the following description, and, partly from specification, become apparent, perhaps understand by implementing the present invention.Purpose of the present invention and other advantages can realize and obtain by specifically noted structure in the specification of being write, claims and accompanying drawing.

Description of drawings

Accompanying drawing is used to provide further understanding of the present invention, and constitutes the part of specification, is used from explanation the present invention with embodiments of the invention one, is not construed as limiting the invention.In the accompanying drawings:

Fig. 1 is the schematic diagram of multipath signal phase mutual interference in the conventional method;

Fig. 2 is a flow chart of determining method according to the signal interference ratio that elimination multipath of the present invention disturbs;

Fig. 3 is the comparison diagram (the Beta value is according to calculation of parameter) of the estimation average of the present invention and conventional method;

Fig. 4 is the comparison diagram (the Beta value is according to calculation of parameter) of the evaluated error of the present invention and conventional method;

Fig. 5 is the comparison diagram (Beta estimates to obtain) of the estimation average of the present invention and conventional method; And

Fig. 6 is the comparison diagram (Beta estimates to obtain) of the evaluated error of the present invention and conventional method.

Embodiment

Below in conjunction with accompanying drawing the preferred embodiments of the present invention are described, should be appreciated that preferred embodiment described herein only is used for description and interpretation the present invention, and be not used in qualification the present invention.

Though below be that example describes with WCDMA, principle of the inventive method and step are equally applicable to other cdma system.

Fig. 1 is the schematic diagram of multipath signal phase mutual interference in the conventional method.

Energy distribution on the antenna as shown in Figure 1 is: noise N=1, and the energy in article one footpath is S1ant=2, and the energy in second footpath is S2ant=3, and then the actual value of SIR should be SF* (2+3)/Beta/1=5*SF/Beta.In demodulating process, the interference in article one footpath is I1ant=S2ant+N=4, and the interference in second footpath is I2ant=S1ant+N=3.N is big for the interference ratio noise, and the interference in two footpaths varies in size.Be SIR=SF* (2+3)/Beta/ ((3+4)/2)=1.43*SF/Beta with what the algorithm for estimating of the SIR of conventional method obtained, itself and actual value ratio differ greatly, and relative error surpasses 70%.

Fig. 2 is a flow chart of determining method according to the signal interference ratio that elimination multipath of the present invention disturbs.As shown in Figure 2, may further comprise the steps:

S202, determine user terminal signal each bar footpath the average interference noise and according to the signal energy of average interference noise calculation signal at certain time slot;

S204 determines the Beta value;

S206 according to signal energy and Beta value, determines the multipath interfering energy of signal, removes the multipath interfering energy, and definite external disturbance energy; And

S208 determines signal interference ratio according to signal energy and external disturbance energy.

Signal interference ratio according to the present invention is determined method, and the average interference noise in each bar footpath is determined by following formula:

$\mathrm{Ine}{w}_s=\frac{1}{2*P*(\mathrm{Npilot}-1)}\underset{p=1}{\overset{P}{\mathrm{\&Sigma;}}}\underset{k=1}{\overset{\mathrm{Npilot}-1}{\mathrm{\&Sigma;}}}{\left|\right|\mathrm{Pilo}{t}_{p,s}\left(k\right)-\mathrm{Pilo}{t}_{p,s}(k-1)\left|\right|}^2$ , and

I _s＝Inew _s

Wherein, Pilot _{P, s}(k) frequency pilot sign of the s time slot in p bar footpath on antenna of expression, Npilot represents the total number of the pilot tone of each time slot, and P represents the total number of multipath on this antenna, and s represents the s time slot, and I _sExpression average interference noise.

Further comprising the steps of in S206:

It is average according to following formula the average interference noise to be carried out filtering in time, obtaining the average interference noise,

I _s＝AlphaI*I _s-1+(1-AlphaI)*Inew _s，

Wherein, AlphaI is more than or equal to 0 and smaller or equal to 1 coefficient, I _sIt is the average interference noise of s time slot.

Signal energy in this method is determined by following formula:

$S_s=\frac{1}{\mathrm{<figure-callout\; id="2"\; label="Npilo\; t"\; filenames="A20071014535500161.png,A20071014535500171.png"\; state="\{\{state\}\}">Npilo</figure-callout>}{t}^{}{}^2}\underset{p=1}{\overset{P}{\mathrm{\&Sigma;}}}[{\left|\right|\underset{k=1}{\overset{\mathrm{Npilot}}{\mathrm{\&Sigma;}}}\mathrm{Pilo}{t}_{p,s}\left(k\right)\left|\right|}^2-\frac{P}{\mathrm{Npilot}}{I}_s],$

Wherein, S _sThe signal energy of representing the s time slot.

Simultaneously, the Beta value is determined by following formula:

$\mathrm{Beta}=\frac{S_s+\underset{i=2}{\overset{K}{\mathrm{\&Sigma;}}}[\underset{p=1}{\overset{P}{\mathrm{\&Sigma;}}}{A_{p,i}}^2-P*I_s*\mathrm{<figure-callout\; id="1"\; label="S\; F"\; filenames="A20071014535500161.png,A20071014535500171.png"\; state="\{\{state\}\}">S</figure-callout>}{F}_{}{}_1/S{F}_i]}{S_s},$

Wherein, K represents to have on the user terminal K bar uplink physical channel, A _{P, i}The signal averaging amplitude of the i bar physical channel of expression user terminal behind the descrambling and de-spreading of p bar footpath, and SF _iBe the employed spreading factor of descrambling and de-spreading, wherein, the spreading factor SF of DPCCH in the WCDMA system ₁Be 256.

Signal interference ratio according to the present invention is determined method, and the Beta value can also be determined by following formula:

$\mathrm{Beta}=\frac{\underset{i=1}{\overset{K}{\mathrm{\&Sigma;}}}{B_i}^2}{{{\mathrm{<figure-callout\; id="1"\; label="B"\; filenames="A20071014535500161.png,A20071014535500171.png"\; state="\{\{state\}\}">B</figure-callout>}}_1}^2},$

Wherein, Bi represents the emission amplitude adjustment factor of all up channel i, and B ₁For the amplitude of DPCCH is adjusted the factor.

In the present invention, the multipath interfering energy of signal is determined by following formula:

$\mathrm{Nne}{w}_s=I_s-\frac{P-1}{P}*\mathrm{Beta}*S_s/\mathrm{<figure-callout\; id="1"\; label="S\; F"\; filenames="A20071014535500161.png,A20071014535500171.png"\; state="\{\{state\}\}">S</figure-callout>}{F}_{}{}_1$

Wherein, Nnew _sThe multipath interfering energy of expression signal.

According to signal interference ratio computational methods of the present invention, the external disturbance energy is determined by following formula:

N _s＝AlphaN*N _s-1+(1-AlphaN)*Nnew _s

Wherein, AlphaI is more than or equal to 0 and smaller or equal to 1 coefficient, and N _sExpression external disturbance energy.

Fig. 3 is the comparison diagram (the Beta value is according to calculation of parameter) of the estimation average of the present invention and conventional method.

Fig. 3 is on the basis of example shown in Figure 1, and keeping the energy ratio between two footpaths is 3: 2, keeps noise energy N constant simultaneously, adjusts the gross energy in two footpaths.By the different antenna opening Ec/IO of emulation (ratio of chip energy and interference noise energy), compare the performance difference of the inventive method and conventional method.The parameter of emulation is set to:

Multipath number P=2;

Number of pilots Npilot=6; And

UE has two physical channels, the amplitude factor B1=Bc=15 of article one physical channel DPCCH, and the amplitude factor B2=Bd=11 of the 2nd physical channel DPDCH, Beta can calculate by B1 and B2, is 1.5378.

For each Ec/IO point, ask average by the data of emulation 100 frames.

From Fig. 3, no matter SIR is much, and method of the present invention is all more near real SIR, and SIR is big more, and the evaluated error of conventional method is just big more.

Fig. 4 is the comparison diagram (the Beta value is according to calculation of parameter) of the evaluated error of the present invention and conventional method.

Fig. 4 has further embodied the difference of the inventive method and conventional method, and when antenna opening Ec/IO from 1 to 5, the SIR Estimation of Mean error of conventional method reaches 30%～70%.And the evaluated error of the inventive method remains essentially in a very little scope, and relative error is substantially below 10%.

Fig. 5 is the comparison diagram (Beta estimates to obtain) of the estimation average of the present invention and conventional method.

Fig. 6 is the comparison diagram (Beta estimates to obtain) of the evaluated error of the present invention and conventional method.

Fig. 5 and Fig. 6 and Fig. 3 and Fig. 4 are similar, and just the Beta value does not calculate by B1 and B2, but according to $\mathrm{Beta}=\frac{\underset{i=1}{\overset{K}{\mathrm{\&Sigma;}}}{B_i}^2}{{{\mathrm{<figure-callout\; id="1"\; label="B"\; filenames="A20071014535500161.png,A20071014535500171.png"\; state="\{\{state\}\}">B</figure-callout>}}_1}^2}$ Estimation obtains.From the result, the relative error of the inventive method is still below 15%, and is more much better than conventional method.

In sum, the signal interference ratio that adopts elimination multipath of the present invention to disturb determines that method has improved the SIR estimation performance significantly, has avoided effectively owing to SIR estimates the inaccurate power control fails that causes, thereby has further caused the phenomenon of system performance degradation.

Be the preferred embodiments of the present invention only below, be not limited to the present invention, for a person skilled in the art, the present invention can have various changes and variation.Within the spirit and principles in the present invention all, any modification of being done, be equal to replacement, improvement etc., all should be included within protection scope of the present invention.

Claims (8)

1. a signal interference ratio of eliminating the multipath interference is determined method, it is characterized in that, comprising:

Step 1, determine user terminal signal each bar footpath the average interference noise and determine the signal energy of described signal according to described average interference noise at certain time slot;

Step 2 is determined the Beta value;

Step 3 according to described signal energy and described Beta value, is determined the multipath interfering energy of described signal, removes described multipath interfering energy, and definite external disturbance energy; And

Step 4 is determined signal interference ratio according to described signal energy and described external disturbance energy.

2. signal interference ratio according to claim 1 is determined method, it is characterized in that, the average interference noise in described each bar footpath is determined by following formula:

${\mathrm{Inew}}_s=\frac{1}{2*P*(\mathrm{Npilot}-1)}\underset{p=1}{\overset{P}{\mathrm{\&Sigma;}}}\underset{k=1}{\overset{\mathrm{Npilot}-1}{\mathrm{\&Sigma;}}}{\left|\right|{\mathrm{Pilot}}_{p,s}\left(k\right)-{\mathrm{Pilot}}_{p,s}(k-1)\left|\right|}^2,$ And

I _s＝Inew _s

Wherein, Pilot _{P, s}(k) frequency pilot sign of the s time slot in p bar footpath on antenna of expression, Npilot represents the total number of the pilot tone of each time slot, and P represents the total number of multipath on this antenna, and s represents the s time slot, and I _sExpression average interference noise.

3. signal interference ratio according to claim 2 is determined method, it is characterized in that, and is further comprising the steps of in the step of determining described average interference noise:

It is average according to following formula described average interference noise to be carried out filtering in time, obtaining described average interference noise,

I _s＝AlphaI*I _s-1+(1-AlphaI)*Inew _s，

Wherein, AlphaI is more than or equal to 0 and smaller or equal to 1 coefficient, I _sIt is the described average interference noise of s time slot.

4. determine method according to claim 2 or 3 described signal interference ratios, it is characterized in that described signal energy is determined by following formula:

$S_s=\frac{1}{{\mathrm{Npilot}}^2}\underset{p=1}{\overset{P}{\mathrm{\&Sigma;}}}[{\left|\right|\underset{k=1}{\overset{\mathrm{Npilot}}{\mathrm{\&Sigma;}}}{\mathrm{Pilot}}_{p,s}\left(k\right)\left|\right|}^2-\frac{P}{\mathrm{Npilot}}{I}_s],$

Wherein, S _sThe signal energy of representing described s time slot.

5. signal interference ratio according to claim 4 is determined method, it is characterized in that, described Beta value is determined by following formula:

$\mathrm{Beta}=\frac{S_s+\underset{i=2}{\overset{K}{\mathrm{\&Sigma;}}}[\underset{p=1}{\overset{P}{\mathrm{\&Sigma;}}}{A_{p,i}}^2-P*I_s*{\mathrm{SF}}_1/{\mathrm{SF}}_i]}{S_s},$

Wherein, K represents to have K bar uplink physical channel, A on the described user terminal _{P, i}The signal averaging amplitude of i bar physical channel behind the descrambling and de-spreading of p bar footpath of representing described user terminal, and SF _iBe the employed spreading factor of descrambling and de-spreading, wherein, the spreading factor SF of DPCCH in the WCDMA system ₁Be 256.

6. signal interference ratio according to claim 4 is determined method, it is characterized in that, described Beta value is determined by following formula:

$\mathrm{Beta}=\frac{\underset{i=1}{\overset{K}{\mathrm{\&Sigma;}}}{B_i}^2}{{B_1}^2},$

Wherein, Bi represents the emission amplitude adjustment factor of all up channel i, and B ₁For the amplitude of DPCCH is adjusted the factor.

7. determine method according to claim 5 or 6 described signal interference ratios, it is characterized in that the multipath interfering energy of described signal is determined by following formula:

${\mathrm{Nnew}}_s=I_s-\frac{P-1}{P}*\mathrm{Beta}*S_s/{\mathrm{SF}}_1,$

Wherein, Nnew _sThe multipath interfering energy of representing described signal.

8. signal interference ratio according to claim 7 is determined method, it is characterized in that, described external disturbance energy is determined by following formula:

N _s＝AlphaN*N _s-1+(1-AlphaN)*Nnew _s，

Wherein, AlphaI is more than or equal to 0 and smaller or equal to 1 coefficient, and N _sRepresent described external disturbance energy.

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