CN101112025A - Interference estimation in the presence of frequency errors - Google Patents

Abstract

Methods and apparatus for estimating interference level in a receiver are dominated by the receiver's residual frequency error when the interference is low. The interference estimation method can be changed when the interference is low such that it compensates for the effects of residual frequency errors. A method of estimating an interference level includes the steps of detecting an interference level of the received signal; determining whether the detected interference level is low; and if the detected interference level is low, estimating the interference level by at least one of estimating in only a radial direction and de-rotating the received signal before estimating the interference level.

Description

Interference when having frequency error is estimated

Technical field

The present invention relates to the electronic digit communication system, more particularly, relate to the receiver in the wireless communication system.

Background technology

Digital communication system comprises time division multiple access (TDMA) system and code division multiple access (CDMA) system, this time-division multiple address system for example has the cellular radiotelephone system that meets GSM telecommunication standard and enhancing standard (for example GSM/EDGE) thereof, and this code division multiple access system for example has the cellular radiotelephone system that meets IS-95, cdma2000 and wideband CDMA (WCDMA) telecommunication standard.Digital communication system also comprises the system of " mixing " TDMA and CDMA, the cellular radiotelephone system that for example meets Universal Mobile Telecommunications System (UMTS) standard, this Universal Mobile Telecommunications System (UMTS) standard specifies the third generation (3G) mobile system in the IMT-2000 of International Telecommunication Union framework, developed of ETSI (ETSI).Third generation partnership project (3GPP) has been issued UMTS and WCDMA standard.For the purpose of simplifying, the application focuses on the WCDMA system, but should be appreciated that, can realize the principle of describing among the application in other digital communication systems.

WCDMA wherein, separates base station and physical channel (terminal or user) by the pseudo noise scrambling code respectively based on direct sequence spread spectrum skill with the orthogonal channel sign indicating number on down link (base station is to terminal) direction.Because users all in cdma system share identical radio frequency (RF) resource, are important so every physical channel does not use the power more than necessity.This realizes that by through-put power control (TPC) mechanism wherein, the base station sends the TPC order to the user on down link (DL) direction, and the user realizes these orders on up link (UL) direction, and vice versa.The TPC order makes the user increase with a plurality of increments or reduces the power level that they transmit, and keeps the target signal interference ratio (SIR) of the DPCH (DPCH) between base station and the user thus.DPCH comprises Dedicated Physical Data Channel (DPDCH) and the Dedicated Physical Control Channel (DPCCH) among UL and the DL.DPDCH carrying upper layer network signaling, and may go back voice-bearer and/or Video service, and DPCCH carrying physical layer control signaling (for example, pilot symbols/signals, TPC order etc.).Used the WCDMA term here, but should be appreciated that, other system has corresponding term.Scramble and channel code and through-put power are controlled at known in the art.

Fig. 1 represents the communication system such as the WCDMA system, and this communication system comprises base station (BS) 100, and these base station 100 processing in this example are connected with four travelling carriages (MS) 1,2,3,4.In down link, BS 100 transmits to each travelling carriage with corresponding power level, and uses orthogonal code that the signal by BS 100 transmission is carried out spread spectrum (spead).In up link, MS 1-MS 4 transmits to BS 100 with corresponding power level.Each BS in this system (being called as Node B with the 3GPP term) is for being divided into the geographic area service of one or more sub-district.These BS are connected to corresponding wireless network controller (RNC, not shown among Fig. 1) by dedicated telephone line, optical fiber link, microwave link etc.RNC guiding MS or subscriber equipment (UE) are called out by suitable BS, and RNC is connected to the external network such as public switch telephone network (PSTN), the Internet etc. by one or more core network node (for example, mobile switching centre's (not shown) and/or packet radio service node (not shown)).

Therefore WCDMA is designed to operate with low signal-to-noise ratio (SNR), has designed WCDMA algorithm such as SIR estimator and automatic frequency control (AFC) algorithm at this situation.For example, use is designed to the SIR algorithm for estimating that obtains enough service quality (QoS) use under low SIR in through-put power control (TPC) scheme.Usually with block error rate (BLER) QoS is quantized.Should be appreciated that, in WCDMA system (and other adopts the communication system of direct sequence (DS) spread spectrum), noise (N) comprises thermal noise and interference, this is because of cause the spread spectrum of signal to make interference signal show to such an extent that be similar to noise (that is, the expansion of frequency and have the level of Noise Background (noise floor)) owing to interference signal " mistake " spreading code.

SIR is used to inner loop power control, has almost man-to-man mapping for BLER because suppose it.The exterior ring power control of operating with low responsiveness also is included among the WCDMA, with the remaining mismatch between compensation SIR and the BLER.It is known that power control and SIR to BLER are mapped in this area, and for example at Louay M.A.Jalloul etc. " SIREstimation and Closed-Loop Power Control for 3G ", IEEE pp.831-835 is described in (2003).

In this communication system, BS transmits predetermined frequency pilot sign on the DPCH of UE.This BS also goes up transmitted pilot symbol in Common Pilot Channel (CPICH), and UE uses the CPICH frequency pilot sign usually when estimating wireless channel to the impulse response (impulse response) of BS.Should be realized that,, estimate, that is, be used for the control of DL power but UE still mainly uses the DPCH pilot tone to carry out SIR because the common higher SNR of CPICH makes UE use the CPICH pilot tone to carry out channel estimating and do not use the DPCH pilot tone.

Be known that equally good more SIR estimator provides good more receiver performance, this receiver performance is measured as the required quantity of power of given BLER target, and the low more then performance of power demand is good more.In order to improve the SIR estimator among the WCDMA, can use CPICH to carry out I and estimate, and only use the DPCH pilot tone to estimate the S part of SIR.This for example is described in people's such as Lindoff US patent application publication NO.2005/0094816 " Interference Estimation in CDMASystems Using Alternative Scrambling Codes ".Below five The Representation Equation this SIR estimator.

For S, required signal is estimated S _i ^DPCHProvide by following formula:

$S_i^{\mathrm{DPCH}}={\left|{\hat{h}}_{\mathrm{DPCH},i}\right|}^2$

Equation 1

Wherein,

${\hat{h}}_{\mathrm{DPCH},i}=\frac{1}{n_p}\underset{k=1}{\overset{n_p}{\mathrm{\Σ}}}{u}_k^p{y}_{\mathrm{DPCH},i}^{*}\left(k\right)$

Equation 2

And n _pBe the DPCH frequency pilot sign u of every time slot _k ^PQuantity, y _{DPCH, i}(k) be to separate spread spectrum DPCH frequency pilot sign at what rake rake referred to (rake finger) i, and * refer to complex conjugate at moment k.

For I, interference signal is estimated I _i ^DPCHProvide by following formula:

$I_i^{\mathrm{DPCH}}=\frac{{\mathrm{SF}}_C}{{\mathrm{SF}}_D}{I}_i^{\mathrm{DPICH}}$

Equation 3

SF wherein _CBe at the spreading factor that is used to calculate I estimated channel (for example CPICH), and SF _DBe the spreading factor (is under the situation of different channel at the two) of estimating the channel (for example DPCH) that will be transformed at I, and:

$I_i^{\mathrm{CPICH}}=\frac{1}{N_C-1}\underset{k=1}{\overset{N_c}{\mathrm{\Σ}}}|y_{\mathrm{CPICH},i}\left(k\right)-{\hat{h}}_{\mathrm{CPICH},i}{u}_k^{\mathrm{CPICH}}{|}^2$

Equation 4

U wherein _k ^CPICHBe CPICH frequency pilot sign k,

Be CPICH channel estimating at tap i, y _{CPICH, i}(k) be to separate spread spectrum CPICH frequency pilot sign at what rake rake referred to i at moment k, and N _CBe quantity at the frequency pilot sign of the every time slot that is used for obtaining the I estimated channel.In the WCDMA communication system, SF _CBe generally 256, and the every time slot of CPICH have ten frequency pilot signs.In this example, the CPICH symbol (that is ten symbols) in time slot is used to determine that I estimates.Should be appreciated that, can use the symbol of varying number, and different communication systems can have the symbol of varying number in time slot.

Estimate SIR for SIR _EST:

${\mathrm{SIR}}_{\mathrm{EST}}=\underset{i=1}{\overset{n_f}{\mathrm{\Σ}}}\frac{S_i^{\mathrm{DPCH}}}{I_i^{\mathrm{DPCH}}}$ Equation 5

N wherein _fBe the quantity that the rake rake refers to.

Under the situation of laboratory tests and standard inspection (benchmark), suppose the good signal quality usually, terminal is operated with good SNR in other words.In addition, in this case, need good terminal behavior, this means that then required downlink power should be less if the SNR of CPICH is higher.The terminal behavior of " non-good " is described below, comprises long power control loop transition.In this case, residual frequency error (frequency error that stays after tuning correction of AFC to receiver) is bigger to the influence of I estimation effect comparison BLER.Should be appreciated that, depend critically upon other SIR of interference order and changed the SIR fiducial value of exterior ring power control, and because the slow-response of exterior ring power control has produced long transition, wherein the downlink power rank is set to too high to the mapping of BLER.Therefore, having obtained wrong SIR in these cases estimates.

Summary of the invention

Exist under the situation of residual frequency error, wishing by estimating that interference I's (and SIR) avoids the behavior of current SIR algorithm for estimating than good algorithm.The inventor has observed and has interfered under the lower situation, and I estimates that processing is controlled by residual frequency error.This can influence SIR estimates still can not influence BLER, therefore when detecting the situation with low interference, can change I and estimate tactful (it is a part of estimating this SIR), with the influence of compensating residual frequency error.

According to an aspect of the present invention, provide a kind of interference order method for distinguishing of estimating the signal that receives in the receiver.This method may further comprise the steps: the interference rank that detects the signal that receives; Determine whether detected interference rank is lower; And if detected interference rank is lower, then by only estimating diametrically and before estimate interfering rank, going at least a in the rotation (de-rotating) to estimate to interfere rank to the received signal.

According to a further aspect in the invention, provide a kind of other device of interference order of estimating the signal that receives in the receiver.This device comprises detector, and this detector is constructed to detect the interference rank of the signal that receives; And processor, this processor is constructed to determine whether detected interference rank is lower, if and detected interference rank is lower, then by only estimate diametrically and before estimate interfering rank, go to the received signal to rotate in at least aly estimate to interfere rank.

According to a further aspect in the invention, provide a kind of computer-readable recording medium, this computer-readable recording medium comprises other computer program of interference order of the signal that is used for estimating that receiver receives.This computer program is carried out following steps: the interference rank that detects the signal that receives; Determine whether detected interference rank is lower; And if detected interference rank is lower, then by only estimate diametrically and before estimate interfering rank, go to the received signal to rotate in at least aly estimate to interfere rank.

Description of drawings

Read this explanation in conjunction with the drawings and will understand various aspects of the present invention, feature and advantage, in the accompanying drawings:

Fig. 1 represents communication system;

Fig. 2 is the block diagram of the illustrative user device in the communication system;

Fig. 3 is a flow chart of estimating the interference order method for distinguishing; And

Fig. 4 is a flow chart of estimating other modified method of interference order.

Embodiment

Fig. 2 is the block diagram of the part of the receiver 200 (for example, the portable terminal in the WCDMA communication system) according to many aspects of the present invention.Radio signal is received by suitable antenna 202, and is changed and be sampled to baseband signal 204 times by front end receiver (FeRX).This time conversion hypothesis carrier frequency is f _CThen, the sampling of baseband signal is input to path-searcher 206, this path-searcher 206 makes the sampling that receives be associated with known pilot signal, and estimated path postpones overview, and this, overview was imported into rake combiner 208 and channel estimator and SIR estimator 210 in path delay.210 pairs of pilot channels of rake combiner 208 and channel estimator are separated spread spectrum, estimate the impulse response of wireless channel, and the echo that is received (echo) of the data that received is separated spread spectrum and combination with control character.Other pieces among Fig. 2 are described below, should be appreciated that, this receiver can be arranged by other of the functional block shown in Fig. 2 and realize.

Rake combination and channel estimating are known in the art.The various aspects of rake receiver: G.Turin " Introduction to Speed-SprectrumAntimultipath Techniques and Their Application to Urban Digital Radio " described in following document, Proc.IEEE, vol.68, pp.328-353 (in March, 1980); Authorize the United States Patent (USP) NO.5 of the title of Dent, 305,349 for " QuantizedCoherent Rake Receiver "; Authorize the patent No.6 of the title of Bottomley, 363,104 for " Method and Apparatus for Interference Cancellation in a RakeReceiver "; Authorize the patent No.6 of people's such as Wang title, 801,565 for " Multi-Stage RakeCombining Methods and Apparatus "; People's such as Wang title is the US patent application publication No.2001/0028677 of " Apparatus and Methods for Finger Delay Selection in Rake Receivers ".Channel estimating for example is described in following document: people's such as Wilhelmsson title is the US patent application publication No.2005/0105647 of " Channel Estimation by AdaptiveInterpolation ".

Shown in the flow chart of Fig. 3, whether estimation interference order method for distinguishing can comprise or can interfere the step (step 302) of Grade I and definite subsequently (step 304) detected I rank to be hanged down and improve by comprising detection.For example, quality of signals that can be by estimating to receive (the ratio E of chip energy (chip energy) and interference energy for example _C/ I ₀), determine then whether this quality surpasses (cross) threshold value and detect the situation with low interference.For example, the suitable estimation of the quality of received signal is to use the intensity index (RSSI) of the sign indicating number power (RSCP) of the signal that receives divided by the signal that receives, for example E _C/ I ₀=RSCP/RSSI, wherein RSCP=E _CIt is the signal code power of CPICH.Signal quality estimation and RSCP value and RSSI value are preferably generated by path-searcher 206, and one or more in them (for example is provided for high-rise processing, be used for handover measurement), and be provided for control unit (CU) 212 according to the embodiment of the present invention.The signal quality that the operation of software programming that can be by control unit is provided with is estimated can or even be carried out by suitable comparator by the processor CU 212 of suitable configuration or programming with the comparison of threshold value.About the suitable value of threshold value or the scope of value,, think at present and work as E for the WCDMA communication system _C/ I ₀Be approximately-during 8dB the signal rank begin enough good.

Should be appreciated that, also can detect and have other situation of low interference order with other modes.For example,, can consider the SIR of CPICH, rather than consider the E of aforesaid CPICH according to following formula _C/ I ₀:

${\mathrm{SIR}}_{\mathrm{EST}}=\underset{i=1}{\overset{n_f}{\mathrm{\Σ}}}\frac{S_i^{\mathrm{CPICH}}}{I_i^{\mathrm{CPICH}}}$ Equation 6

Use SIR rather than E _C/ I ₀Advantage be that sir measurement does not comprise that quadrature interferes, this quadrature is interfered the performance that does not influence terminal.

Be also to be understood that in the WCDMA communication system if use SIR, SIR then described herein estimates and the preferably every time slot of other steps of these methods is carried out once, if perhaps use E _C/ I ₀Ratio, then every 30-100 millisecond is carried out once.In other communication systems, these methods are to carry out with the method that depends on system.

If detected I rank is not low, then can uses above equation 3 and 4 to generate I and estimate (step 306) with conventional method.If the I rank is lower, i.e. E _C/ I ₀Higher (for example greater than-8dB), then this information (be represented as in Fig. 2 and be/deny signal) is imported into channel and SIR estimator 210, and channel and SIR estimator 210 generate I estimation (step 308) by carrying out with the corresponding I method of estimation of information that is described in more detail below.These estimators 210 also generate the estimation of channel filter taps h with any means in the several different methods as known in the art.Then, rake combiner 208 uses h and I to estimate to decode to the received signal, and is created on the SIR estimation of using in the subsequent treatment that is included in the power control loop in mode as known in the art.

The I method of estimation

Residual frequency error is generally 0-50Hz, and is considered to estimate by I the main contributor of the interference that quantizes at present.Usually, when having (less) residual frequency error between the frequency of the frequency of the carrier signal that receives and the local oscillator of receiver (LO) 214, the CPICH symbol of separating spread spectrum can be written as:

$y_{\mathrm{CPICH},i}\left(k\right)=e^{\mathrm{j\Δk}}{\stackrel{\‾}{y}}_{\mathrm{CPICH},i}\left(k\right)$ Equation 7

That is to say that the phase shift that frequency error can be regarded as between continuous symbol k, the k+1 is Δ=2 π f _e/ R _CSymbol rotation, f wherein _eBe residual frequency error, R _CThe is-symbol rate, and y-bar is the zero error symbol.For WCDMA system, R _C=(spreading rate)/SF _C=(3.84MHz)/SF _C, therefore SF for example _CThe symbol rate of=256 CPICH is R _C=15000 symbol per seconds, and N _CThe every time slot of=10CPICH frequency pilot sign.For low E _C/ I ₀Situation, carry out S and I routinely according to above equation 1-4 and estimate, but for high E _C/ I ₀Therefore and interfering situation by residual frequency error control, any one that preferably will be in the following modified method or both are used for the I estimation.

Method 1: estimation I diametrically only

In an embodiment of the invention, estimate to interfere a kind of modified method of I (eliminating) to use following equation for little residual frequency error (that is, in the WCDMA system less than 50Hz) because the interference of frequency error:

Equation 8

And

$I_i^{\mathrm{DPCH}}=\frac{{\mathrm{SF}}_C}{{\mathrm{SF}}_D}{I}_i^{\mathrm{CPICH}}$ Equation 9

Wherein φ is

Angle, the real part of the plural x of Re (x) expression, other are measured as hereinbefore defined.Therefore, this modified method (step 308 among Fig. 3) comprises that calculating I according to equation 8 and 9 estimates.Utilize this I to estimate, can calculate SIR according to above equation 5 and estimate.

Should be appreciated that,, make " radially " be parallel to real reference axis because the angle of channel estimating compensates.Be also to be understood that in many receivers,, make residual frequency error in the scope of 10-60Hz owing to quantize.In the WCDMA communication system, for using method 1 obtains good estimation, residual frequency error should be less than about 100Hz.

Method 2: before calculating I, signal is gone rotation

According to another embodiment of the present invention, a kind of modified method of estimating to interfere I comprises that the estimation based on the residual frequency error of correspondence compensates symbol or the sampling that receives.AFC device 216 from the receiver of operating in mode well known in the art 200 can easily obtain the estimation of residual frequency error.For example, authorize people's such as Atarius U.S. Patent No. 6,606,363 have described the method and apparatus that is used for coming by combined pilot symbol and data symbol estimated frequency skew, and people's such as Dent the open No.WO 02/29978A2 in the world has described and is used for automatic frequency control method and device in the cdma receiver.The step of this modified method is described in the flow chart of Fig. 4 and comprises:

For example estimate residual frequency error f by obtaining this from AFC device 216 _e(step 402); And

For each symbol, use corresponding phase shift that the CPICH symbol that receives is gone rotation according to following formula:

${\tilde{y}}_{\mathrm{CPICH},i}\left(k\right)=e^{-\mathrm{j\&Delta;k}}{y}_{\mathrm{CPICH},i}=e^{-\mathrm{<figure-callout\; id="2"\; label="j"\; filenames="A20068000342500161.png"\; state="\{\{state\}\}">j</figure-callout>}2\mathrm{\&pi;}{f}_{e}k/R_C}{y}_{\mathrm{CPICH},i},k=1,...,N_C$ Equation 10

Wherein

Be symbol through going to rotate, Δ=2 π f _e/ R _CWith other parameters as mentioned above.

Then, can use symbol through going to rotate

Estimate to interfere Grade I and SIR according to above equation 1-5.Should be appreciated that equation 10 can be used for CPICH channel in addition (for example, DPCH).

Usually because before calculate interfering, proofreaied and correct (estimation) residual frequency error, so from the angle method 2 " good " of performance in method 1, but method 2 may more difficult realization.Method 1 only goes up estimating noise in a direction (radially); Because it is identical that the noise on the orthogonal direction is assumed to be, so total interference is estimated as the twice of the interference that directly makes progress.In addition, method 1 has good being similar to for little residual frequency error.Think that at present in some implementations, method 1 ratio method 2 is simple and easy, but in other were realized, method 2 ratio method 1 were simple and easy.Certainly, should be appreciated that in other were realized, method 1 and 2 can be used in combination.

Should be appreciated that above-mentioned process is carried out as required repeatedly, respond with for example time variation matter to the communication channel between the transmitter and receiver.In addition, this explanation still should be appreciated that other channels also can be suitable at writing such as the channel of DPCH and CPICH.Because CPICH has covered the whole zone and the pilot tone of the sub-district in the WCDMA system and sent continuously, be favourable so use the CPICH frequency pilot sign.Yet, can on another channel, (for example directly on DPCH) estimate I, in this case, equation 8 uses the DPCH parameter and ignores the conversion of equation 9.

For the ease of understanding, according to action sequence many aspects of the present invention are described, these action sequences can be carried out by the unit of for example programmable computer system.Should be realized that exercises can be by the program command of special circuit (for example, interconnecting to carry out the discrete logic gate of dedicated functions, perhaps application-specific integrated circuit (ASIC)), one or more processor execution, perhaps both combinations are carried out.The wireless receiver of realizing embodiments of the present invention for example can be included in mobile phone, beep-pager, earphone, laptop computer and other portable terminals etc.

In addition, can consider in addition the present invention is completely contained in the computer-readable recording medium of arbitrary form, wherein store suitable instruction set for using or and instruction executive system, device or equipment (for example computer based system, comprise the system of processor or can obtain instruction and the other system of execution command from medium) are connected.As used herein, " computer-readable medium " can be can comprise, storage, transmission, propagation or transmission procedure be for any device of using or and instruction executive system, device or equipment are connected.Computer-readable medium for example can be but be not limited to electronics, magnetic, light, electromagnetism, infrared or semiconductor system, device, equipment or propagation medium.The example more specifically of computer-readable medium (non exhaustive tabulation) comprises electrical connection, portable computer diskette, random-access memory (ram), read-only memory (ROM), Erasable Programmable Read Only Memory EPROM (EPROM or flash memory) and the optical fiber with one or more leads.

Therefore, the present invention can implement in many different forms, and is not only above-described form of ownership, and all these forms is considered within the scope of the invention.For each aspect in the multiple aspect of the present invention, this arbitrarily form can be called as " logic " that " being constructed to " carries out described action, perhaps alternatively is called as " logic " of carrying out described action.

Should emphasize, when using in this application, term " comprises (comprises) " and " comprising (comprising) " expression exists described feature, integral body, step or assembly, but does not get rid of existence or increase one or more feature, integral body, step, assembly or their combination.

Above-mentioned embodiment only is exemplary and should not be considered as the restriction that is subjected to any way.Scope of the present invention is determined by following claim, and is intended to contain all changes and the equivalent that falls in the claim scope.

Claims (20)

1. interference order method for distinguishing of estimating the signal that receives in the receiver, this method may further comprise the steps:

The interference rank of the signal that detection receives;

Determine whether detected interference rank is lower; And

If detected interference rank is lower, then by only estimate diametrically and before estimate interfering rank, go to the received signal to rotate in at least aly estimate to interfere rank.

2. method according to claim 1 wherein, detects the interference rank by estimating the quality of signals that receives, and determines whether lower step comprises whether definite described quality surpasses predetermined threshold value to detected interference rank.

3. method according to claim 2, wherein, described quality is a chip energy and the ratio of interference energy.

4. method according to claim 3, wherein, described quality is the intensity index of the sign indicating number power of the signal that receives divided by the signal that receives.

5. method according to claim 1, wherein, described radial parallel is in real reference axis.

6. method according to claim 5, wherein, only estimate to interfere rank diametrically according to following equation:

And

$I_i^{\mathrm{DPCH}}=\frac{{\mathrm{SF}}_C}{{\mathrm{SF}}_D}{I}_i^{\mathrm{CPICH}}$

Wherein, I _i ^DPCHBe other estimation of interference order on the first channel DPCH at receiver tap i, I _i ^CPICHBe other estimation of the interference order on second channel CPICH at this tap i, k is a time index, SF _CBe spreading factor at described second channel, SF _DBe spreading factor at described first channel, N _CBe the symbol quantity of the every time slot on the described second channel, φ is

Angle, y _{CPICH, i}(k) be at tap i state second channel in moment k place separate the spread spectrum frequency pilot sign,

Be channel estimating at the described second channel of tap i, and u _k ^CPICHIt is the frequency pilot sign that second channel is stated in moment k place.

7. method according to claim 1, wherein, by estimating residual frequency error, and use the symbol in the corresponding phase shift to the received signal to go rotation at each symbol, go to the received signal rotation, the phase shift of described correspondence provides by following equation:

${\tilde{y}}_{\mathrm{CPICH},i}\left(k\right)=e^{-j2\mathrm{\&pi;}{f}_{e}k/R_C}{y}_{\mathrm{CPICH},i},k=1,...,N_C$

Wherein,

Be the symbol through going to rotate of channel CPICH, k is an index, f _eBe residual frequency error, N _CBe the symbol quantity of the every time slot on this channel, and R _CBe the symbol rate on this channel, and use symbol through going to rotate

Estimate to interfere rank.

8. method according to claim 1, wherein, described receiver is operated in the wide band CDMA radio communication system.

9. other device of interference order of a signal that is used for estimating that receiver receives, this device comprises:

Detector, this detector are constructed to detect the interference rank of the signal that receives; And

Processor, this processor is constructed to determine whether detected interference rank is lower, if and detected interference rank is lower, then by only estimate diametrically and before estimate interfering rank, go to the received signal to rotate in at least aly estimate to interfere rank.

10. device according to claim 9, wherein, described detector detects the interference rank by estimating the quality of signals that receives, and described processor determines whether described quality surpasses predetermined threshold value.

11. device according to claim 10, wherein, described quality is a chip energy and the ratio of interference energy.

12. device according to claim 11, wherein, described quality is to use the intensity index of the sign indicating number power of the signal that receives divided by the signal that receives.

13. device according to claim 9, wherein, described radial parallel is in real reference axis.

14. device according to claim 13, wherein, described processor is constructed to only estimate to interfere rank diametrically according to following equation:

And

$I_i^{\mathrm{DPCH}}=\frac{{\mathrm{SF}}_C}{{\mathrm{SF}}_D}{I}_i^{\mathrm{CPICH}}$

Wherein, I _i ^DPCHBe other estimation of interference order on the first channel DPCH at receiver tap i, I _i ^CPICHBe other estimation of the interference order on second channel CPICH at this tap i, k is a time index, SF _CBe spreading factor at described second channel, SF _DBe spreading factor at described first channel, N _CBe the symbol quantity of the every time slot on the described second channel, φ is

Angle, y _{CPICH, i}(k) be at tap i state second channel in moment k place separate the spread spectrum frequency pilot sign,

Be channel estimating at the described second channel of tap i, and u _k ^CPICHIt is the frequency pilot sign that second channel is stated in moment k place.

15. device according to claim 9, wherein, described processor is constructed to by estimating residual frequency error, and use the symbol in the corresponding phase shift to the received signal to go rotation at each symbol, go to the received signal rotation, the phase shift of described correspondence provides by following equation:

${\tilde{y}}_{\mathrm{CPICH},i}\left(k\right)=e^{-j2\mathrm{\&pi;}{f}_{e}k/R_C}{y}_{\mathrm{CPICH},i},k=1,...,N_C$

Wherein,

Be the symbol through going to rotate of channel CPICH, k is an index, f _eBe residual frequency error, N _CBe the symbol quantity of the every time slot on this channel, and R _CBe the symbol rate on this channel, and use symbol through going to rotate

Estimate to interfere rank.

16. device according to claim 9, wherein, described receiver is operated in the wide band CDMA radio communication system.

17. a computer-readable recording medium that comprises other computer program of interference order of the signal that is used for estimating that receiver receives, wherein, described computer program is carried out following steps:

The interference rank of the signal that detection receives;

Determine whether detected interference rank is lower; And

If detected interference rank is lower, then by only estimate diametrically and before estimate interfering rank, go to the received signal to rotate in at least aly estimate to interfere rank.

18. medium according to claim 17 wherein, detects the interference rank by estimating the quality of signals that receives, and determines whether lower step comprises whether definite described quality surpasses predetermined threshold value to detected interference rank.

19. medium according to claim 17 wherein, only estimates to interfere rank diametrically according to following equation:

And

$I_i^{\mathrm{DPCH}}=\frac{{\mathrm{SF}}_C}{{\mathrm{SF}}_D}{I}_i^{\mathrm{CPICH}}$

Wherein, I _i ^DPCHBe other estimation of interference order on the first channel DPCH at receiver tap i, I _i ^PICHBe other estimation of the interference order on second channel CPICH at this tap i, k is a time index, SF _CBe spreading factor at described second channel, SF _DBe spreading factor at described first channel, N _CBe the symbol quantity of the every time slot on the described second channel, φ is

Angle, Y _{CPICH, i}(k) be at tap i state second channel in moment k place separate the spread spectrum frequency pilot sign, Be channel estimating at the described second channel of tap i, and u _k ^CPICHIt is the frequency pilot sign that second channel is stated in moment k place.

20. medium according to claim 17, wherein, by estimating residual frequency error, and use the symbol in the corresponding phase shift to the received signal to go rotation at each symbol, go to the received signal rotation, the phase shift of described correspondence provides by following equation:

${\tilde{y}}_{\mathrm{CPICH},i}\left(k\right)=e^{-j2\mathrm{\&pi;}{f}_{e}k/R_C}{y}_{\mathrm{CPICH},i},k=1,...,N_C$

Wherein,

Be the symbol through going to rotate of channel CPICH, k is an index, f _eBe residual frequency error, N _CBe the symbol quantity of the every time slot on this channel, and R _CBe the symbol rate on this channel, and use symbol through going to rotate

Estimate to interfere rank.

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