CN100568760C - Downlink channel estimating processing method under the multi-antenna multi-user TDD mode - Google Patents

Abstract

The invention discloses the downlink channel estimating processing method under a kind of multi-antenna multi-user TDD mode, step comprises: carry out channel estimating, obtain each user's multipath channel information; Calculate the energy information of the channel impulse response tap that each user obtains respectively, and these energy informations and threshold value are for the first time compared; If greater than the threshold value first time, then think useful multipath, write down and keep this footpath data, to channel estimating tap zero clearing less than the threshold value first time; The energy of each user's that will obtain channel impulse response tap summation respectively compares each channel impulse response gross energy of obtaining respectively with threshold value for the second time, user's the channel impulse response zero setting less than the threshold value second time; Send into the joint-detection module according to the channel estimation value judgement joint-detection activated code channel number that obtains together with the channel estimation value that the second time, the threshold value judgement obtained and carry out the subscriber signal detection.

Description

Downlink channel estimating processing method under the multi-antenna multi-user TDD mode

Technical field

The present invention relates to the reception of the down link in a kind of mobile communication system, specifically, relate to the downlink channel estimating processing method under a kind of multi-antenna multi-user TDD mode.

Background technology

In the relatively shorter TDD mobile communcations system of spreading code, can use joint detection algorithm to receive at the UE end, in common joint detection algorithm, each user's channel estimation value all can be by increasing the method for reprocessing thresholding, remove the false-alarm tap that exists in some channel estimating, in ordinary circumstance, add this thresholding and all can take down the major part of the false-alarm tap of this user's channel impulse response.When base station down uses beam form-endowing method to launch, if other users' position and targeted customer's position is different, targeted customer's downlink forming weights can provide figuration gain to this subscriber signal, and the effect that other subscriber signals are suppressed, like this, the targeted customer is except receiving the signal of oneself, also receive being suppressed of other users signal, spatial separation effect that down beam shaping method brings that Here it is.

With reference to shown in Figure 1, the processing gain of the training sequence in the TDD system is than higher, channel estimating post-processing approach according to the common adding thresholding first time (being signal-noise ratio threshold), can obtain other users' more much lower channel estimating than targeted customer's channel estimating power, prove through emulation, the lower channel estimating of these power is equivalent to the false-alarm tap for targeted customer's joint-detection, and the joint-detection that these false-alarm taps participate in the targeted customer can exert an influence to the detection performance of targeted customer's signal.

At publication number CN1731887A, denomination of invention is in " CDMA system random access threshold multi-path selection method ", propose a kind of secondary thresholding that adds and improved the method that inserts detection probability at random, in this method, utilize a fixing secondary thresholding that the signal power that is inserted is judged.Because thresholding is fixed, and can not adapt to different scenes, thereby can not reach optimum performance.

Summary of the invention

Technical problem solved by the invention provides the downlink channel estimating processing method under a kind of multi-antenna multi-user TDD mode, in the descending receiving course of antenna system, by increasing the constraint that other subscriber channels are estimated, provide the raising of targeted customer's combined detection performance.

Technical scheme is as follows:

Downlink channel estimating processing method under the multi-antenna multi-user TDD mode, step comprises:

(1) carries out channel estimating, obtain each user's multipath channel information;

(2) calculate the energy information of the channel impulse response tap that each user obtains respectively, and these energy informations and threshold value are for the first time compared; If greater than the threshold value first time, then think useful multipath, write down and keep this footpath data, if less than the threshold value first time, then think the interference footpath that noise produces, with the channel impulse response tap zero clearing in this footpath;

(3) energy of each user's that will obtain respectively channel impulse response tap summation, each channel impulse response gross energy of obtaining is compared with threshold value for the second time respectively, of user's the channel impulse response tap zero setting of channel impulse response gross energy less than the threshold value second time;

(4) judge joint-detection activated code channel number according to the channel estimation value that obtains, with described joint-detection activated code channel number and for the second time threshold value judge that the channel estimation value that obtains sends into the joint-detection module together and carry out subscriber signal and detect.

Further, step (1) is specially: the training sequence that target UE end UE is received carries out channel estimating, estimates the channel estimation value in all channel estimation windows in the time slot.

Further, in the step (3), with the energy summation of targeted customer's channel impulse response tap of obtaining, the value that the energy summation is obtained deducts a definite value then, produces described second time of threshold value.

Further, in the step (3), described definite value receives code channel power and disturbs code channel dynamically to determine according to UE.

Adopt the method for the invention, compared with prior art, reduced the number of users of participating in joint-detection, reduced the complexity of system's computing, save operation time for the user equipment (UE) chip in realization, and improved the performance that the targeted customer receives data, reduced the error rate.

Description of drawings

Fig. 1 is the flow chart of prior art;

Fig. 2 is a main flow chart of the present invention;

Fig. 3 is the flow chart of the preferred embodiment of the present invention.

Embodiment

In the TDD system, a kind of figuration gain dynamic adjusted threshold that can provide according to many antennas need be provided, thereby reduce the method that subscriber channel is estimated false-alarm, can improve the receptivity of user in the multiaerial system like this, mainly be to adopt the method that adds the secondary thresholding to improve user's receptivity at receiving terminal.In the descending receiving course of antenna system, by increasing the constraint that other subscriber channels are estimated, provide the raising of targeted customer's combined detection performance, the inventive method is particularly useful for using associated detecting method to receive the subscriber equipment of detection.

With reference to the accompanying drawings, the preferred embodiments of the present invention are described in detail.

With reference to shown in Figure 2, the downlink channel estimating processing method under the multi-antenna multi-user TDD mode is specific as follows:

Step S201:UE receives downlink data, and this downlink data comprises training sequence.

Step S202: carry out channel estimating, obtain each user's multipath channel information.

The training sequence that target UE end UE is received carries out channel estimating, estimates the channel estimation value in all channel estimation windows in the time slot.

Step S203: calculate the energy information of the channel impulse response tap that each user obtains respectively, and these energy informations and threshold value (note is made T1) are for the first time compared.

For greater than thresholding T1, think useful multipath, write down and keep this footpath data; For less than thresholding T1, think the interference footpath that noise produces, with this footpath channel estimating tap zero clearing.

Step S204: carry out the thresholding judgement second time.

The energy of each user's that will obtain channel impulse response tap summation respectively, each channel impulse response gross energy of obtaining is compared with threshold value (note is made T2) for the second time respectively, of user's the channel impulse response zero setting of channel impulse response gross energy less than the threshold value second time.

Step S205: the channel estimation value that obtains according to step S204 rejudges joint-detection activated code channel number, with it with send into the joint-detection module together through the channel estimation value of threshold judgement for the second time and carry out subscriber signal and detect.

Step S206: obtain target user data.

With reference to shown in Figure 3, be example with the TD-SCDMA communication system of descending employing intelligent antenna beam shaping method, the preferred embodiments of the present invention are carried out concrete description.

Step S301:UE receives training sequence.

Step S302: the user carries out channel estimating to the training sequence that receives.

If the number of users of the time slot at targeted customer's received signal place is 8,, be designated as respectively: H so can from training sequence, estimate 8 users' channel impulse response ₁, H ₂..., H ₈, establish H ₁Channel impulse response for user self.

Step S303: carry out the thresholding judgement first time.

If H _iGreater than thresholding T1, execution in step S304; Otherwise execution in step S305.

If i user's channel estimating is H _i, H _i=[h _1i, h _2i..., h _Wi], wherein w represents that channel estimation window is long.If j tap h _JiPower less than thresholding T1, then this tap zero setting, obtain i user's channel post-processing channel estimation value H ' like this _i, all users' channel post-processing channel estimation value is designated as: H ' ₁, H ' ₂..., H ' ₈

Step S304: obtain threshold value (note is made T2) for the second time according to object UE channel estimating gross energy.

(note is made P to calculate the gross power of each subscriber channel impulse response respectively _i), with H ' ₁, H ' ₂..., H ' ₈Substitution P _iIn, that is:

$P_i=\underset{j=1}{\overset{w}{\mathrm{\Σ}}}{h}_{\mathrm{ji}}^{\′}\·h_{\mathrm{ji}}^{\′*}$

Obtain P ₁, P ₂..., P ₈, according to P ₁Calculate thresholding T2 for the second time with A, wherein, A is received code channel power and is disturbed code channel dynamically to determine by UE.So just make T2 according to the power of targeted customer's channel impulse response.With T2 and P ₁, P ₂..., P ₈Send into step S306 together.

Step S305: the false-alarm tap to each user's channel impulse response is got rid of.

For H less than thresholding T1 _i(H _i＜T ₁) think the interference footpath that noise produces, with this footpath channel estimating tap zero clearing.

If j tap h _JiPower less than thresholding T1, then this tap zero setting.

Step S306: carry out the thresholding judgement second time.

According to thresholding T2 and P ₁, P ₂..., P ₈To the H ' that obtains among the step S303 ₁, H ' ₂..., H ' ₈Carry out as acting.If P _iMore than or equal to thresholding T2, execution in step S307; Otherwise execution in step S308.

With the channel estimation value H that finally obtains " ₁, H " ₂..., H " ₈Send into step S307 and step S308 respectively.

Step S307: if P _i〉=T ₂, make H " _i=H ' _i

According to efficient channel estimated value excited users code channel, promptly according to H " ₁, H " ₂..., H " ₈Value judge excited user number, if H " _iBe not 0, remember that then this user activates, the total number of users N that statistics activates sends into N among the step S309.

Step S308: if P _i＜T ₂, H then " _i=0.

A little less than thinking that this interference user signal energy is too, the channel estimation value zero clearing.

Step S309: carry out joint-detection.

According to user's received signal, H " ₁, H " ₂..., H " ₈Carry out joint-detection with N, export user data to be demodulated.

Step S310: obtain target user data.

In sum, the inventive method is by the further judgement to the subscriber channel estimated value, the spatial separation characteristic of utilizing beamforming algorithm to provide, remove the channel estimation value of the more weak interference user of signal, make it not participate in targeted customer's joint-detection, can improve the user like this and detect performance, and reduce the complexity of subscriber equipment.

Claims (4)

1, the downlink channel estimating processing method under a kind of multi-antenna multi-user TDD mode, step comprises:

(1) carries out channel estimating, obtain each user's multipath channel information;

(2) calculate the energy information of the channel impulse response tap that each user obtains respectively, and these energy informations and threshold value are for the first time compared; If greater than the threshold value first time, then think useful multipath, write down and keep this footpath data, if less than the threshold value first time, then think the interference footpath that noise produces, with the channel impulse response tap zero clearing in this footpath;

(3) energy of each user's that will obtain respectively channel impulse response tap summation, each channel impulse response gross energy of obtaining is compared with threshold value for the second time respectively, of user's the channel impulse response tap zero setting of channel impulse response gross energy less than the threshold value second time;

(4) judge joint-detection activated code channel number according to the channel estimation value that obtains, with described joint-detection activated code channel number and for the second time threshold value judge that the channel estimation value that obtains sends into the joint-detection module together and carry out subscriber signal and detect.

2, the downlink channel estimating processing method under the multi-antenna multi-user TDD mode according to claim 1, it is characterized in that, step (1) is specially: the training sequence that target UE end UE is received carries out channel estimating, estimates the channel estimation value in all channel estimation windows in the time slot.

3, the downlink channel estimating processing method under the multi-antenna multi-user TDD mode according to claim 1, it is characterized in that, in the step (3), energy summation with targeted customer's channel impulse response tap of obtaining, the value that energy summation is obtained deducts a definite value then, produces described second time of threshold value.

4, the downlink channel estimating processing method under the multi-antenna multi-user TDD mode according to claim 3 is characterized in that, in the step (3), described definite value receives code channel power and disturbs code channel dynamically to determine according to UE.

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