CN1780156A - Signalling dry-ratio estimation - Google Patents

Abstract

A method for evaluating the signal-interference-noise ratio (SINR) includes such steps as evaluating the signal power S by adding the evaluated channel powers of current frame on the paths provided by path search module, evaluating the interference and noise power N by adding the evaluated channel powers of current frame on the paths, and calculating the SINR by the equation SINRk=S/N/D, where D is the evaluated channel length.

Description

Signal to interference and noise ratio (SINR) estimating method

Technical field

The present invention relates to a kind of signal to interference and noise ratio (SINR) estimating method, particularly a kind ofly in the automatic frequency correction of time-division (TimeDivision) wireless communication system receiver, carry out the Signal to Interference plus Noise Ratio estimation approach.

Background technology

In typical wireless communication system, owing to have frequency departure between the local oscillator (LocalOscillator) of transmitter and receiver, can cause the serious decline of received signal quality, even the communications failure.Particularly, for (the User Equipment of the user terminal in the cell mobile communication systems, UE), consideration for economic factor etc., the normal lower local oscillator of frequency stability that adopts, its original frequency deviation (Initial Frequency Offset) can reach about 10ppm, and this is equivalent to the original frequency deviation about 20kHz to the system that adopts the 2GHz carrier wave.If do not take the frequency output of corresponding measure correcting local oscillator, make its output frequency consistent or, the failure that may cause signal to transmit very near (for example, deviation is in 0.1ppm) with transmitter.On the other hand, because local oscillator is used to transmit and receive simultaneously, the serious band of generation disturbs (out-of-bandinterference) outward so big frequency departure can cause transmitting equally.In receiver, be used to realize that the device of Frequency Synchronization often is called as automatic frequency correction (Automatic Frequency Correction is called for short " AFC ") device.

General, when initial frequency departure is big, the situation when for example reaching 10ppm, automatic frequency correction can be divided into coarse frequency correcting (Coarse AFC) and fine frequency is proofreaied and correct (Fine AFC) two stages.This be because:

(1) receiver is in when start, often will pass through steps such as a series of time, frequency, sign indicating number and frame structure be synchronous, finishes synchronous and system's access function.And for different synchronous phases, desired received signal quality and the target that can reach also are inconsistent usually.That is some stage only needs rough Frequency Synchronization to get final product, and other stages then require more accurate Frequency Synchronization; On the other hand, some stage can only reach rough Frequency Synchronization according to the information that can utilize, and other stages are because the available information increase can realize more accurate Frequency Synchronization;

(2) for a key modules in the automatic frequency correction (AFC), be that frequency departure is estimated (Frequency Offset Estimation, be called for short " FOE ") module, weigh its performance and mainly contain two indexs: be i.e. frequency departure estimated accuracy and maximum frequency deviation estimation range.If the actual frequency deviation surpasses this scope, serious deviation just might take place in the output of FOE module so.And various FOE methods often have a common characteristic: promptly the precision of Gu Jiing is high more, and its maximum frequency deviation scope of supporting is also just more little; Otherwise if will support bigger frequency departure scope, then its estimated accuracy will reduce.When having relatively high expectations (for example 0.1ppm) for the bigger situation of original frequency deviation (for example 10ppm) and final frequency deviation, generally need to adopt different frequency offset estimation algorithm of two covers and corresponding AFC strategy thereof, finish coarse frequency correcting and fine frequency respectively and proofread and correct two processes.

General, from the transmitting of transmitter, regular meeting continuous or periodically have pilot tone (Pilot) or (SYNC) code word synchronously, they are known or by detected someway at the receiver place.So the AFC module can utilize these code words as training sequence (Training Sequence), after a series of processing of corresponding received signal process, finish the work of frequency correction.Although AFC also can carry out under the pattern of training sequence the unknown, promptly so-called " blind " be mode (blind), and its performance particularly is lower than under the 0dB situation generally relatively poor in signal to noise ratio, general less application in the existing wireless communications system.

(Time-Division) system was meant the communication frequency resource was divided into a plurality of time slots (Timeslot) by time shaft time-division, and each logic channel (Logical Channel) takies one or more time slot and transmits.Time-division system comprise time division multiple access (Time Division Multiple Access, TDMA) system and time division duplex (Time Division Duplex) system etc.It is GSM and TD-SCDMA that two covers adopt the example of the typical cellular mobile system of time division technique.In these systems, certain part of each time slot usually has one section synchronization code word or training sequence, be used to help the receiver deadline synchronously, functions such as Frequency Synchronization and channel estimating.On the other side is that those adopt frequency or code word to separate the system of Different Logic channel, for example IS-95 and WCDMA, in these systems, generally have continuous pilot transmitted channel (Pilot Channel), may adopt relatively more flexible way to finish a series of synchronizing functions based on this continuous pilot channel, comprise Frequency Synchronization function etc.

Some are in the designed AFC method of DS-SS cdma system (comprising IS-95 and WCDMA etc.), suppose to have the existence of continuous pilot signal, adopted phase difference detection (DifferentialDetection) or discrete Fourier transform (DFT) methods such as (Discrete Fourier Transform) to carry out Frequency offset estimation, and realized that in conjunction with the RAKE receiver structure multipath merges.For example, at International Patent Application Publication No. WO9931816, denomination of invention is among " a kind of method and apparatus that carries out frequency acquisition and tracking in the DS-CDMA receiver " (Method and Apparatus for Frequency Acquisition andTracing for DS-SS CDMA Receiver), a kind of AFC structure based on RAKE receiver is disclosed, and can adopt the variable-length relevant treatment to carry out the frequency departure estimation approach adaptively in the different AFC stage, can in the DS-SS cdma system, obtain preferable performance.

Yet, for time-division system, TD-SCDMA system for example, its pilot signal generally is discontinuous, and may should not adopt the RAKE receiver structure because it adopts Multiuser Detection (Multi-User Detection) method.Therefore, many at DS-SS cdma system design automatic frequency correcting method and be not suitable for the time division multiple access connecting system.In addition, different with arrowband time-division system (as GSM) in the past is, in broadband time-division system (for example TD-SCDMA system), and Signal to Interference plus Noise Ratio (the Signal-to-Interference-and-Noise Ratio on each chip (chip), be called for short " SINR ") very low, its representative value is lower than 0dB.Therefore, just no longer suitable under this low SINR situation at some suitable AFC methods of arrowband time-division system in the past.Therefore, the AFC method and apparatus that design meets the demands at the broadband time-division system is one of key issue in these system designs.

For radio communication mobile communication system particularly, multipath fading be frequency diffusion (Frequency Dispersive) phenomenon to ubiquity in its propagation channel, can cause the SINR value of received signal bigger fluctuating can occur within a short period of time.On the other hand,, can life period spread (Time Dispersive) phenomenon again simultaneously, promptly produce serious intersymbol interference (Inter-Symbol Interference, ISI) problem for CDMA broadband communication systems such as (code division multiple accesss).Good receiver scheme at mobile communication system, must solve above two aspects problem---this is no exception for AFC Module Design in the receiver.

Often there are following one or several weak points in existing AFC method and apparatus at the time division communication system design:

(1) do not distinguish coarse frequency correcting and fine frequency and proofread and correct two processes, but adopt the unified AFC scheme of a cover: owing to above-mentioned reason, this scheme has often caused the contradiction between frequency departure estimation range and the frequency departure estimated accuracy, and/or the information that can utilize when failing effectively to utilize receiver to be in each stage.For example, route searching, tracking and channel estimation module generally just can obtain preferable performance after coarse frequency correcting is finished, and can be utilized by the fine frequency timing.On the other hand, in different phase, have different training sequences and can be used to the frequency departure correction.For example, at international monopoly WO0303040, denomination of invention is among " a kind of automatic frequency correcting method under the 3G radio communication TDD mode " (Automatic Frequency Correction Method and Apparatus for TimeDivision Duplex Modes of 3G Wireless Communications), a kind of method of carrying out frequency correction under 3G system time division duplex (TDD) pattern (HCR-TDD) is disclosed, but it is not distinguished coarse frequency correcting and fine frequency correction, but adopt the identical method and apparatus of a cover to realize frequency calibration function, and fail hour to utilize channel estimating and route searching in frequency deviation, the information of tracking module, thus therefore the convergence rate of its AFC loop is lost.

(2) ignored multipath fading (frequency diffusion) common in the radio communication channel to the influence that automatic frequency correcting method caused, perhaps ignored intersymbol interference (time diffusion) common in the broadband system influence that automatic frequency correcting method caused.For example, at United States Patent (USP) 2003099206, denomination of invention is among " automatic frequency correcting method and device " (Method and Arrangement for AutomaticFrequency Correction), frequency calibrating method under a kind of UTRA tdd mode is disclosed, but only having adopted the strongest propagation path to carry out frequency departure estimates, adopted the fixing AFC loop gain factor simultaneously, therefore performance can be received certain influence under the situation of decline and many strong propagation path existence fast, and its correction accuracy is also very limited.

Though the part automatic frequency correcting method also is divided into several stages with AFC, and adopt the different AFC loop gain factors to control convergence and the tracking performance of AFC under the different phase in each, but its AFC stage switches often and to judge by certain convergence and to carry out in stage.For example, adopt the mean value of recent Frequency offset estimation output valve to be used as the estimation of current frequency offseting value, and by comparing the switching judging criterion that is used as different phase with several thresholdings that set in advance (threshold) value.But, in these schemes, because the inaccuracy that convergence is judged, perhaps owing to needing the long period just can obtain convergence judgement comparatively accurately, so under the low signal-to-noise ratio condition, often need the long time to reach the convergence of AFC loop.On the other hand,, can not dynamically adjust, so the performance under some communication environment may be relatively poor according to actual channel condition because the relevant AFC parameter in these methods generally is to establish in advance.

Summary of the invention

The object of the present invention is to provide a kind of signal to interference and noise ratio (SINR) estimating method, thereby can under the low SINR condition, and communication channel life period diffusion and frequency spread condition under, quickly and accurately the local oscillator frequencies and the oscillator frequency in the transmitter of receiver are carried out synchronously.

For achieving the above object, technical scheme of the present invention is as follows:

A kind of signal to interference and noise ratio (SINR) estimating method comprises the steps:

The signal power estimating step, the active path positional information according to path searcher module provides with the average estimated channel power addition of present frame on these paths, obtains signal power estimated value S;

Disturb and the noise power estimating step, the noise path information that provides according to path searcher module obtains interference and noise power estimated value N with the average estimated channel power addition of present frame on these paths;

Calculate the Signal to Interference plus Noise Ratio estimated value of present frame: SINR according to following formula _k=S/N/D, wherein D is the channel estimating correlation length.

Adopt said method, can be under very low SINR condition, the simple Signal to Interference plus Noise Ratio estimation that also realizes exactly in the time-division system.Especially, the present invention is directed to two kinds of common in the wide-band mobile communication system abominable channel conditions, be i.e. under frequency diffusion and the time spread condition, can keep good performance equally.

Description of drawings

Fig. 1 is for carrying out the structured flowchart that fine frequency is proofreaied and correct in the TD-SCDMA system;

Fig. 2 is in fine frequency trimming process as shown in Figure 1, a kind of schematic diagram that carries out the method for Path selection based on the time delay envelope;

Fig. 3 is a schematic diagram of the present invention, shows a kind of flow chart that utilizes channel estimating and route searching result to carry out the SINR estimation approach in fine frequency trimming process as shown in Figure 1;

Fig. 4 carries out the flow chart of Kalman (Kalman) gain factor Calculation Method in fine frequency trimming process as shown in Figure 1; And

The implementation structure block diagram of the first-order loop filter of Fig. 5 in fine frequency correcting structure as shown in Figure 1.

Embodiment

According to Fig. 1 to Fig. 5, provide better embodiment of the present invention, and described in detail below, enable to understand better function of the present invention, characteristics.

Fig. 1 carries out the structured flowchart that fine frequency is proofreaied and correct in the TD-SCDMA system according to the present invention.Described fine frequency trimming process is based on that Kalman (Kalman) filter theory realizes by a first-order loop.At first, received RF signal is through down-conversion demodulator 1010 and through being converted into digital baseband signal behind ADC, AGC and the RRC filter, follow the sampled data in the Midamble receiving unit that signal data extractor 1011 is 144 chips according to length in the last P-CCPCH channel of frame synchronization information extraction TS0, corresponding to 2 times of over-sampling situations, extracted 144 * 2=288 Midamble data sampling altogether.This segment data sampling plays an important role for system synchronization, will be used in channel estimating, route searching, SINR estimation and the frequency offset estimation module.Corresponding length is that 144 Midamble training sequence is produced by Midamble codeword generator 1012, and its codewords indexes is detected by the previous search of initial zone second step Step 2.

Then, this section Midamble data sampling is admitted to channel estimating and path searcher module 1013.This module is relevant by Midamble data sampling and corresponding Midamble training sequence are carried out (circulation), obtains one group of channel estimation value.The average estimated channel power value that calculates in the present frame, constituted the time delay envelope (Delay Profile) of present frame, and route searching is according to the time delay envelope of present frame and in conjunction with the time delay envelope of former some frames, and, judge which paths is an active path according to some default Path selection threshold value.Note owing to adopted 2 samplings, so the resolving accuracy in path is 1/2 chip width.Because channel estimating and route searching particularly mobile communication system extensive use of wireless communication system in each are so the relevant technologies personnel are very familiar to its related algorithm and implementation method in this area, so repeat no more here.Here channel estimating will be exported the amplitude and the phase value in all paths in so-called " channel estimation window ", for example, the channel estimating window width can be decided to be 16 chips, and corresponding to 2 times of over-samplings, common property is given birth to the amplitude and the phase value of 16 * 2=32 paths in this estimating window.Wherein, described every paths is represented a time delay tap (Delay Tap).Simultaneously, channel estimating also can be exported channel estimating all channel estimation values outside window in the correlation length, offers when module such as measurement is estimated parameter such as SINR to use.On the other hand, the path searcher module positional information of active path in the delivery channel estimating window then.Here suppose that path searcher module produces L bar active path positional information at most.Other module in the receiver comprises demodulation (Demodulation) module, synchronous (Synchronization) module and measurement (Measurement) module etc., will utilize these active path positional informations and channel estimation value to carry out relevant work.

With reference to figure 2, be depicted as a kind of schematic diagram that carries out the method for Path selection based on the time delay envelope.Wherein, the time delay envelope in the present frame is to obtain by (perhaps similar approach) after the channel estimation results in the present frame being asked mould.With the time delay envelope in the time delay envelope of present frame and the some frames before by certain mode carried out average after, the time delay envelope of gained is used to carry out Path selection.In the example as shown in Figure 2, on average the length of the time delay envelope after is 16, that is contains 16 time delay tap.When carrying out Path selection, at first need to determine a Path selection thresholding, this threshold value can add that a fixing deviant obtained afterwards based on the maximum path power in this time delay envelope or based on the average power in all paths in this time delay envelope.Certainly, also can adopt other method to obtain this Path selection threshold value.After determining this Path selection thresholding, just can carry out Path selection: in the time delay envelope, every performance number is higher than the Path selection thresholding, all select as " active path ", otherwise then as " noise path ".For example, in example shown in Figure 2, relative time delay is that 3,4,5,10 and 11 path is selected as active path, and remaining path is all by as noise path.

Again with reference to figure 1, the path merges and correlator (module) 1014 utilizes described routing information and corresponding channel estimation value, merge (Maximum Ratio Combining by maximum ratio, be called for short " MRC ") mode carry out the merging of mulitpath, and finish multipath and merge the relevant of back data sequence and training sequence.

Then, with reference to figure 1, the Midamble after this batch merges through multipath receives data and is admitted to frequency offset estimator 1015 with the local Midamble code word that produces through after relevant, and the output frequency skew is estimated

With reference to figure 1, the routing information and the channel estimation results of channel estimating and path searcher module 1013 outputs are admitted in the SINR estimator module 1016, produce present frame SINR estimated value.This SINR estimator also is based on TS0 and goes up the SINR estimated value that Midamble sign indicating number in the P-CCPCH channel obtains present frame.Fig. 3 represents according to the present invention in fine frequency trimming process as shown in Figure 1, a kind of flow chart that utilizes channel estimating and route searching result to carry out the SINR estimation approach.

Wherein, in step 130, according to the active path positional information that path searcher module provides, the SINR estimator just can obtain signal power estimated value S with the average estimated channel power addition of present frame on these paths.Suppose that the set that comprises all paths represents with A, wherein the set P of active path _EExpression, the set P of noise path _NExpression then has A=P _E+ P _NSimultaneously, suppose that channel estimation results can use h={h _i, i ∈ A} represents, and channel estimation results does not carry out normalization according to the channel estimating correlation length.Then signal power estimated value S can calculate with following formula:

$S=\underset{i\∈P_E}{\mathrm{\Σ}}\left|h_i\right|$

On the other hand, in step 131, according to the noise path positional information (being all the non-active paths in the associated window) that path searcher module provides, the SINR estimator just can obtain the average estimated channel power addition of present frame on these paths disturbing and noise power estimated value N.Still continue to use above-mentioned mark, then interference and noise power estimated value N can calculate with following formula:

$N=\underset{i\∈P_N}{\mathrm{\Σ}}\left|h_i\right|$

At last, in step 132, the SINR estimated value of present frame is calculated as follows:

SINR _k＝S/N/D

Wherein, D represents " channel estimating correlation length ", when channel estimating is carried out in representative, and the length of the training sequence that adopts; For preferred embodiment described here, it is the situation in the TD-SCDMA system, this value can be taken as and equals 128---and this is the interior data sampling of back 128 chips that has adopted 144 chip Midamble data because of channel estimating, and the SINR value that will estimate is meant received power and the ratio of being with interior interference noise power spectrum density in each chip.Variable SINR _kSubscript k to represent this be the SINR estimated value that obtains in the k frame.

Then, with reference to figure 1, kalman gain factor calculator 1017 utilizes the SINR of present frame to estimate, carries out the renewal of described first-order loop gain factor.Institute's updated parameters comprises: measure noise variance R _k, estimate variance P _kWith the kalman gain factor K _k, wherein subscript k represents the sequence number of present frame.

Figure 4 shows that the flow chart that in fine frequency trimming process as shown in Figure 1, carries out kalman gain factor Calculation Method according to the present invention.(promptly enter before the fine frequency trimming process) under the initial condition, in step 1501, P ₀Be endowed an initial value, general, P ₀Should be provided with according to the variance that enters fine frequency correction frequency deviation before.According to the present invention, P ₀Should determine that recommendation is P according to the variance of the output frequency deviation of coarse frequency correcting ₀=(2000) ²In addition, P ₀Also can determine according to the SINR value of being surveyed at that time.

Next, the fine frequency means for correcting is started working, and in step 1502, the initial value of frame counter k is made as 1.Then in step 1503, the frequency offset estimating variance R of present frame _kWill be based on the SINR estimated value SINR of present frame _kCalculate, concrete computing formula is:

$R_k=K_R\×\frac{1}{{\mathrm{SINR}}_k}$

This formula obtains at the TD-SCDMA system according to improved Wayne Kramer-La Ao (Cramer-Rao) boundary.Wherein, according to Wayne Kramer-La Ao circle, constant K _RValue should determine according to relevant system parameters:

$K_R=\frac{3}{2{\mathrm{\π}}^2{T}_c^2}\·\frac{1}{N(N^2-1)}$

Wherein, T _cRepresented system's chip width, and N has represented the length of used training data sequence.For TD-SCDMA system, 1/T _c=1.28Mcps, and the length N of used Midamble code word=144 can get K in view of the above _R=(288.8) ²The specifying information of relevant improved Wayne Kramer-La Ao circle, can be outstanding with reference to peace people such as (A.N.D ' Andrea) delivered on the IEEE Transaction on Communication magazine in 1994, name is called the paper of " The Modified Cramer-Rao Bound and Its Applications toSynchronization Parameters ", and one of ordinary skill in the art is easy to grasp.

Follow in step 1504 the kalman gain factor K _kR by present frame calculating _kP with former frame calculating _K-1Try to achieve, according to kalman filtering theory, calculating K _kFormula be:

K _k＝P _k-1(P _k-1+R _k) ^-1

Then in step 1505, judge the K that is calculated _kWhether value is less than a preset value K _LOWIf, K _k＜K _LOW, then enter step 1507, change K _kMake it equal K _LOW, with seasonal P _k=P _K-1Otherwise, if K _k＞=K _LOW, then enter step 1506, according to kalman filtering theory, calculate the K of gained by present frame _kValue and former frame calculate P _K-1Value is calculated P _kValue:

P _k＝(1-K _k)P _k-1

Here, to K _kThe purpose of following amplitude limit is: when loop gain is too small, be difficult to follow the tracks of very fast frequency drift; Therefore, need be to loop gain K _kFollowing amplitude limit is to guarantee to follow the tracks of the upper frequency skew.The Lower Limit Amplitude K that recommends _LOWBe 1/64 or 1/128---K _LOWPreferred value should determine by specific implementation and operational environment.

Then, in step 1508, the output kalman gain factor K that present frame calculated _kTo loop filter.Then in step 1509, frame counter k adds 1, prepares to carry out having in the next frame renewal of related parameter.

Then, with reference to figure 1, first-order loop filter 1018 will be according to input

(Frequency offset estimation that present frame calculates) and K _k(the kalman gain factor that present frame calculates) carries out first-order filtering, and the Frequency offset estimation value that adds up of output present frame

With reference to figure 5, be depicted as the implementation structure block diagram of the first-order loop filter in fine frequency correcting structure as shown in Figure 1 according to the present invention.Wherein, input

At first with the kalman gain factor K _kMultiply each other by a multiplier 161, then with former frame in output

By adder 162 additions, obtain output and can be represented by the formula:

${\hat{f}}_k={\hat{f}}_{k-1}+K_k\mathrm{\Δ}{\hat{f}}_k$

The effect of delayer 163 is the output of preserving present frame

And feedback is used in next frame.

In addition, as a kind of simplification, also can be fixed as loop gain among several particular values, for example { 1.0,0.5,0.1,0.05,0.01} gets the output K of the most approaching above-mentioned kalman gain factor calculator in this set then _kThat value, as present frame control loop yield value.Can simplify relevant operation like this, performance does not have big loss simultaneously.

At last, with reference to figure 1, the output of first-order loop filter 1018 is converted into control voltage according to the voltage-controlled characteristic of local oscillator 1019, and controls local voltage controlled oscillator 1019 through DAC, thereby has finished the fine frequency trimming process in the present frame.In next frame, above-mentioned fine frequency trimming process will repeat.Like this, along with the increase of handling frame number, the output of loop filter control constantly obtains upgrading, and makes 1019 outgoing carrier frequency of local oscillator Constantly approach the practical carrier frequency f of input signal _k, and making difference between them, promptly residual frequency offseting value reaches the desired value (for example, the 0.1ppm of standard defined or lower) that guarantees other module operate as normal in the receiver.

So far, described a kind of preferred forms of the present invention in conjunction with the accompanying drawings in detail.Those of ordinary skill in the art should recognize, here be used to describe various logical units of the present invention, module, circuit and algorithm steps etc., can adopt electronic hardware (electronic hardware), computer software (computer software) or their combination to put into effect.Here all being to describe according to their function usually to various elements, unit, module, circuit and step, adopting hardware or software during realization actually, is that concrete application and the design constraint by whole system decides.Those of ordinary skill in the art should recognize the interchangeability of hardware and software under specific circumstances, and can adopt best mode to realize that a class described in the invention carries out the Signal to Interference plus Noise Ratio estimation approach in the automatic frequency correction of receiver of time-division wireless communication system at concrete application.

For example, here be used to describe various logical units of the present invention, module, circuit and algorithm steps etc., can be in the following ways or their combination realize, comprising: digital signal processor (DSP), special purpose integrated circuit (ASIC), field programmable gate array (FPGA) or other programmable logic device, (discrete) gate (gate) or transistor (transistor) logic of separating, the hardware component (for example register and FIFO) that separates, carry out the processor of a series of firmwares (firmware) instruction, traditional programming software (programmable software) and relevant processor (processor) etc.Wherein, processor can be microprocessor (microprocessor), also can be traditional processor, controller (controller), microcontroller (microcontroller) or state machine (state machine) etc.; Software module can be present in RAM memory, flash memory (flash memory), ROM memory, eprom memory, eeprom memory, register, hard disk, moveable magnetic disc, CD-ROM or any existing known storage medium.

The obviously clear and understanding of those of ordinary skill in the art, the most preferred embodiment that the present invention lifted only in order to explanation the present invention, and is not limited to the present invention, the present invention for the technical characterictic among each embodiment, can combination in any, and do not break away from thought of the present invention.According to carrying out the Signal to Interference plus Noise Ratio estimation approach in a kind of automatic frequency correction that is applied in the time-diviional radiocommunication system disclosed by the invention, can there be many modes to revise disclosed invention, and except the above-mentioned optimal way that specifically provides, the present invention can also have other many embodiment.Therefore, all genus are conceived getable method of institute or improvement according to the present invention, all should be included within the interest field of the present invention.Interest field of the present invention is defined by the following claims.

Claims (3)

1, a kind of signal to interference and noise ratio (SINR) estimating method comprises the steps:

The signal power estimating step, the active path positional information according to path searcher module provides with the average estimated channel power addition of present frame on these paths, obtains signal power estimated value S;

Disturb and the noise power estimating step, the noise path information that provides according to path searcher module obtains interference and noise power estimated value N with the average estimated channel power addition of present frame on these paths;

Calculate the Signal to Interference plus Noise Ratio estimated value SINR of present frame according to following formula _k=S/N/D, wherein D is the channel estimating correlation length.

2, signal to interference and noise ratio (SINR) estimating method as claimed in claim 1 is characterized in that, described channel estimating correlation length D is 128.

3, signal to interference and noise ratio (SINR) estimating method as claimed in claim 1 is characterized in that, described channel estimation results does not carry out normalization according to the channel estimating correlation length.

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