CN103326967A - Channel estimating method and device - Google Patents
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Abstract
The invention relates to a channel estimating method and device. The method comprises the steps of carrying out initial channel estimation on a received signal to obtain an initial channel estimation value, wherein the initial channel estimation value comprises impulse response of a channel with K*W paths; carrying out active window detection on K windows within a time slot according to the initial channel estimation value to obtain N active windows within the time slot; carrying out progressive averaging on impulse response of channels, located at the same position, of each of the N active windows to obtain an average channel estimation value; taking the average channel estimation value instead of the initial channel estimation value corresponding to the same positions of the N active windows as a channel estimation value and outputting the channel estimation value. According to the channel estimating method and device, noise can be suppressed effectively and the performance of channel estimation of a system can be improved.
Description
Technical field
The present invention relates to the mobile communication technology field, relate in particular to a kind of channel estimation methods and device.
Background technology
Code division multiple access (Code Division Multiple Access, CDMA) is based on the wireless communication technology of spread spectrum.(Global System for Mobile Communications, GSM) compares with global system for mobile communications, and CDMA has the plurality of advantages such as broadband, large capacity, anti-fading and interference performance are strong, becomes the basic technology of 3G mobile communication.3G mobile communication commercial network based on CDMA is widely used in the whole world at present, have three technical standards: Wideband Code Division Multiple Access (WCDMA) (Wideband Code Division Multiple Access, WCDMA), CDMA2000 and TD SDMA (Time Division-Synchronous Code Division Multiple Access, TD-SCDMA).
Doing coherent demodulation in the cdma system need to estimate channel impulse response.Channel estimating is based on pilot tone carries out, and for WCDMA, there are pilot tone pattern separately in CDMA2000 and TD-SCDMA system, and for example in the TD-SCDMA system, pilot tone is called middle trained sequence (Midamble).The frame structure of TD-SCDMA system as shown in Figure 1.A 10ms radio frames is comprised of 2 5ms subframes, and 7 conventional time slots (TS0-TS6) and and 3 special time slots (DwPTS, GP, UpPTS) are arranged in each subframe.Conventional structure of time slot as shown in Figure 2.The middle trained sequence places 144 chips in centre of each conventional time slot, at the two ends of middle trained sequence 352 chips is arranged respectively, is used for placing data.The ending of conventional time slot has the protection interval (Gap Period, GP) of 16 chips.The middle trained sequence code that different user adopts in the same time slot is to be that 128 basic middle trained sequence code produces after cyclic shift by length.
Channel estimating in the TD-SCDMA system generally all is that the B.Steiner algorithm obtains initial channel estimation (list of references Steiner B, Baier P W.Low cost channel estimation in the uplink receiver of CDMA mobile radio systems.Frequenz, 1993,47 (11/12): 292-298.), obtain length and be 128 initial channel impulse response, formed by K window.Existing TD-SCDMA system generally all is that each activation window is independently processed after obtaining initial channel estimation, and shorter mention is the processing between the coactivation window not.
When in a time slot be user assignment more than 2 code channels, during namely more than a window, be difficult to the establishment noise, cause the performance of channel estimating to incur loss.And in a time slot, are common situation of TD-SCDMA system for the user assignment code channel number surpasses 2.
Summary of the invention
The purpose of this invention is to provide a kind of channel estimation methods and device, have good performance gain, when in a time slot, being a plurality of window of user assignment, can the establishment noise, can improve the performance that system channel is estimated.
For achieving the above object, first aspect present invention provides a kind of channel estimation methods, and described method comprises:
The signal that receives is carried out initial channel estimation, obtain channel estimation value, described channel estimation value comprises the channel impulse response in K * W bar footpath, and wherein, K represents the number of the window that comprises in the time slot, and W represents the number in the footpath that comprises in the window;
According to described channel estimation value, K window in the time slot activated window detect, N that obtains in the described time slot is activated window, and wherein, N is for activating the number of window, N≤K;
The channel impulse response that described N activation window is positioned at the footpath of same position carries out cumulative mean, obtains the average channel estimation value;
Replace described N channel estimation value that activates the corresponding described same position of window to export as channel estimation value with described average channel estimation value.
In conjunction with first aspect, in the possible execution mode of the first of first aspect, the channel impulse response that described N activation window is positioned at the footpath of same position carries out cumulative mean, obtains the average channel estimation value, comprising:
According to formula
The channel impulse response that described N activation window is positioned at the footpath of same position carries out cumulative mean, obtains the average channel estimation value in the footpath of same position;
Wherein, h
K, jBe the j bar channel impulse response directly of k window before the cumulative mean,
Be the average channel estimation value in j bar footpath, j=1 ..., W, k=1 ..., N.
In conjunction with first aspect, in the possible execution mode of the second of first aspect, when the code channel number of configuration was odd number, the described channel impulse response that described N activation window is positioned at the footpath of same position carried out cumulative mean, obtain the average channel estimation value, comprising:
According to formula
The channel impulse response that front N-1 activation window is positioned at the footpath of same position carries out cumulative mean, obtains front N-1 average channel estimation value that activates the footpath of same position in the window;
According to formula
Obtain N average channel estimation value that activates each bar footpath in the window;
Wherein, h
K, jBe the j bar channel impulse response directly of k window before the cumulative mean,
Be the average channel estimation value in j bar footpath, j=1 ..., W, k=1 ..., N.
In conjunction with first aspect, in the third possible execution mode of first aspect, when the code channel number of configuration was odd number, the described channel impulse response that described N activation window is positioned at the footpath of same position carried out cumulative mean, obtain the average channel estimation value, comprising:
According to formula
The channel impulse response that front N-1 activation window is positioned at the footpath of same position carries out cumulative mean, obtains front N-1 average channel estimation value that activates the footpath of same position in the window;
According to formula
Obtain N average channel estimation value that activates each bar footpath in the window;
Wherein, h
K, jBe the j bar channel impulse response directly of k window before the cumulative mean, hj is the average channel estimation value in j bar footpath, j=1 ..., W, k=1 ..., N.
In conjunction with the first of first aspect possible execution mode or possible execution mode or the third the possible execution mode of the second, in the 4th kind of possible execution mode of first aspect, described obtain the average channel estimation value after, also comprise:
According to formula
The average channel estimation value that described N activation window is positioned at the footpath of same position is weighted processing, wherein, i=1 ..., N, Factor
I, jBe i weighted factor that activates window j bar footpath,
Be the average channel estimation value in j bar footpath,
Be i average channel estimation value that activates window j bar footpath after the weighting;
The described average channel estimation value of described usefulness replaces described N channel estimation value that activates the corresponding described same position of window to export as channel estimation value, comprising:
Replace described N channel estimation value that activates the corresponding described same position of window to export as channel estimation value the average channel estimation value after the weighting processing.
In conjunction with the 4th kind of possible execution mode of first aspect, in the 5th kind of possible execution mode of first aspect, described weighted factor Factor
I, jBe i footpath signal to noise ratio that activates window j bar footpath;
Perhaps, described weighted factor Factor
I, jCarry out value according to default effective diameter interval.
In conjunction with first aspect, in the 6th kind of possible execution mode of first aspect, described method also comprises:
Detect the physical channel type in the described time slot;
When comprising polytype physical channel in the described time slot, the described channel impulse response that described N activation window is positioned at the footpath of same position carries out cumulative mean, obtain the average channel estimation value, comprise: respectively for dissimilar physical channel, the channel impulse response that described N activation window is positioned at the footpath of same position carries out cumulative mean, obtains the average channel estimation value.
In conjunction with first aspect, in the 7th kind of possible execution mode of first aspect, after the activation window in obtaining described time slot, also comprise:
Testing result, the window that activates window is activated the window sign for arranging;
The described channel impulse response that described N activation window is positioned at the footpath of same position carries out cumulative mean, obtains the average channel estimation value, comprising:
According to described activation window sign, the channel impulse response that described N activation window is positioned at the footpath of same position carries out cumulative mean, obtains the average channel estimation value.
Second aspect, the present invention also provides a kind of channel estimating apparatus, and described device comprises: initial channel estimation unit, activation window detecting unit, cumulative mean unit and output unit;
Described initial channel estimation unit, be used for the signal that receives is carried out initial channel estimation, obtain channel estimation value, described channel estimation value comprises the channel impulse response in K * W bar footpath, wherein, K represents the number of the window that comprises in the time slot, and W represents the number in the footpath that comprises in the window;
Described activation window detecting unit for the described channel estimation value that obtains according to described initial channel estimation unit, activates window to K window in the time slot and detects, and N that obtains in the described time slot is activated window, and wherein, N is the number of activation window, N≤K;
Described cumulative mean unit, the channel impulse response that described N of being used for described activation window detecting unit is obtained activation window is positioned at the footpath of same position carries out cumulative mean, obtains the average channel estimation value;
Described output unit is used for replacing described N channel estimation value that activates the corresponding described same position of window to export as channel estimation value with the described average channel estimation value that described cumulative mean unit obtains.
In conjunction with second aspect, in the possible execution mode of the first of second aspect, described cumulative mean unit is according to formula
The channel impulse response that described N the activation window that described activation window detecting unit is obtained is positioned at the footpath of same position carries out cumulative mean, obtains the average channel estimation value in the footpath of same position; Wherein, h
K, jBe the j bar channel impulse response directly of k window before the cumulative mean,
Be the average channel estimation value in j bar footpath, j=1 ..., W, k=1 ..., N.
In conjunction with second aspect, in the possible execution mode of the second of second aspect, when the code channel number of configuration was odd number, described cumulative mean unit was according to formula
The channel impulse response that front N-1 the activation window that described activation window detecting unit is obtained is positioned at the footpath of same position carries out cumulative mean, obtains front N-1 average channel estimation value that activates the footpath of same position in the window; And according to formula
Obtain N the average channel estimation value that activates each bar footpath in the window that described activation window detecting unit obtains; Wherein, h
K, jBe the j bar channel impulse response directly of k window before the cumulative mean,
Be the average channel estimation value in j bar footpath, j=1 ..., W, k=1 ..., N.
In conjunction with second aspect, in the third possible execution mode of second aspect, when the code channel number of configuration was odd number, described cumulative mean unit was according to formula
The channel impulse response that front N-1 the activation window that described activation window detecting unit is obtained is positioned at the footpath of same position carries out cumulative mean, obtains front N-1 average channel estimation value that activates the footpath of same position in the window; And according to formula
Obtain N the average channel estimation value that activates each bar footpath in the window that described activation window detecting unit obtains; Wherein, h
K, jBe the j bar channel impulse response directly of k window before the cumulative mean,
Be the average channel estimation value in j bar footpath, j=1 ..., W, k=1 ..., N.
In conjunction with the first of second aspect possible execution mode or possible execution mode or the third the possible execution mode of the second, in the 4th kind of possible execution mode of second aspect, described device also comprises: weighted units, described weighted units is connected with described cumulative mean unit, is used for according to formula
The average channel estimation value that described N the activation window that described cumulative mean unit is obtained is positioned at the footpath of same position is weighted processing, wherein, i=1 ..., N, Factor
I, jBe i weighted factor that activates window j bar footpath,
Be the average channel estimation value in j bar footpath,
Be i average channel estimation value that activates window j bar footpath after the weighting;
Average channel estimation value after described output unit will be processed through described weighted units weighting replaces described N channel estimation value that activates the corresponding described same position of window to export as channel estimation value.
In conjunction with the 4th kind of possible execution mode of second aspect, in the 5th kind of possible execution mode of second aspect, the weighting Factor in the described weighted units
I, jBe i footpath signal to noise ratio that activates window j bar footpath;
Perhaps, described weighted factor Factor
I, jCarry out value according to default effective diameter interval.
In conjunction with second aspect, in the 6th kind of possible execution mode of second aspect, described device also comprises: the channel type detecting unit, and described channel type detecting unit is connected with described cumulative mean unit, for detection of the physical channel type in the described time slot; When described channel type detecting unit detects when comprising polytype physical channel in the described time slot, described cumulative mean unit is respectively for dissimilar physical channel, the channel impulse response that described N activation window is positioned at the footpath of same position carries out cumulative mean, obtains the average channel estimation value.
In conjunction with second aspect, in the 7th kind of possible execution mode of second aspect, after the activation window of described activation window detecting unit in obtaining described time slot, also be used for testing result is activated the window sign for the window that activates window arranges;
Described cumulative mean unit is according to described activation window sign, and the channel impulse response that described N activation window is positioned at the footpath of same position carries out cumulative mean, obtains the average channel estimation value.
Channel estimation methods provided by the invention and device, for in a time slot, being the situation of a plurality of windows of user assignment, process rear in order to substitute the original channel estimated value by the footpath of same position in a plurality of activation windows of same time slot being carried out cumulative mean, can the establishment noise, can improve the performance that the TD-SCDMA system channel is estimated.
Description of drawings
Fig. 1 is the frame structure schematic diagram of TD-SCDMA system;
Fig. 2 is the conventional structure of time slot schematic diagram of TD-SCDMA system;
The channel estimation methods flow chart that Fig. 3 provides for the embodiment of the invention one;
The channel estimating apparatus schematic diagram that Fig. 4 provides for the embodiment of the invention two.
Embodiment
Below by drawings and Examples, technical scheme of the present invention is described in further detail.
The channel estimation methods flow chart that the embodiment of the invention provides is applicable to the TD-SCDMA system, also possesses in the system of training sequence cyclic shift characteristic applicable to similar TD-SCDMA system.
Embodiment one
Fig. 3 is the channel estimation methods flow chart that the present embodiment provides, and as shown in Figure 3, method of the present invention comprises:
S101, the signal that receives is carried out initial channel estimation, obtain channel estimation value.
The embodiment of the invention can but be not limited to obtain initial channel estimation by the B.Steiner algorithm, thereby obtain the initial channel impulse response that length is P=128, formed by K window.
In general, middle trained Sequence reception signal model is:
y=Gh+n
Wherein, matrix G is the P*KW rank matrix that K user's middle trained sequence code cyclic shift obtains:
H=[h
1,1, h
1,2, h
1, W, h
2,1, h
2,2, h
2, W..., h
K, 1, h
K, 2, h
K, W]
TBe the vector of K user's channel impulse response formation arranged together, W is each user's channel impulse response length, and P=128 is the length of basic middle trained sequence among the TD-SCDMA.Common P=KW, then G is 128*128 rank circular matrixes.According to the B.Steiner algorithm, the least-squares estimation of h is h
Because the cyclic shift characteristic of middle trained sequence code in the TD-SCDMA system,
Can be reduced to:
Wherein: m is matrix G first row.
K subscriber channel impulse response can be expressed as
K=1 wherein ..., K, K are the number (maximum numbers of users) of the window that comprises in the time slot, obtained by the high-level signaling configuration,
Usually claim h
(k)It is the channel impulse response of k window.
The task of channel estimating estimates all K window (a corresponding K user's) channel impulse response exactly from receive signal, therefore, the channel estimation value that obtains by the B.Steiner algorithm comprises K * W bar channel impulse response directly, wherein, K represents the number of the window that comprises in the time slot, W represents the number in the footpath that comprises in the window, and namely the window of channel estimating is long.
S102, according to described channel estimation value, K window in the time slot activated window detects, N that obtains in the described time slot is activated window, wherein, N is the number of activation window, N≤K.
Activate window detection can but be not limited to detect by a threshold value is set, arranging of this threshold value can be first calculates the power in 128 footpaths by delivery (be real part square add imaginary part square) computing etc., from 128 footpaths, select a strongest footpath of power, the power of this most powerful path be multiply by a factor (for example 1/16) as the threshold value of setting, judge the quantity that has in the window above the footpath of this threshold value, the window that quantity is met certain requirements detects as activating window again.
Perhaps, select a strongest window of power from 128 footpaths, the power of this window be multiply by a factor as the threshold value of setting, the window that power is surpassed threshold value detects as activating window, etc.
Optionally, the N in S102 obtains described time slot is activated window, also comprises: testing result is activated the window sign for the window that activates window arranges.
S103, the channel impulse response that described N activation window is positioned at the footpath of same position carry out cumulative mean (namely averaging), obtain the average channel estimation value.
Optionally, according to the described activation window sign that S102 arranges, the channel impulse response that described N activation window is positioned at the footpath of same position carries out cumulative mean, obtains the average channel estimation value.
Particularly, according to formula
The channel impulse response that described N activation window is positioned at the footpath of same position carries out cumulative mean, obtains the average channel estimation value in the footpath of same position.
Wherein, h
K, jBe the j bar channel impulse response directly of k window before the cumulative mean,
Be the average channel estimation value in j bar footpath, j=1 ..., W, k=1 ..., N.
In the typical scene of TD-SCDMA system, if high-level signaling is that user configured code channel number M is odd number, front (M-1)/2 window all distributes full 2 code channels so, and last window distributes a code channel.
Optionally, be the situation that user configured code channel number is odd number for high-level signaling, can be according to formula
The channel impulse response that front N-1 activation window is positioned at the footpath of same position carries out cumulative mean, obtains front N-1 average channel estimation value that activates the footpath of same position in the window; And according to formula
Obtain N average channel estimation value that activates each bar footpath in the window; Wherein, h
K, jBe the j bar channel impulse response directly of k window before the cumulative mean,
Be the average channel estimation value in j bar footpath, j=1 ..., W, k=1 ..., N.That is to say, last activates window and does not participate in the process that cumulative mean is processed.
Perhaps, be the situation that user configured code channel number is odd number for high-level signaling, also can be according to formula
The channel impulse response that front N-1 activation window is positioned at the footpath of same position carries out cumulative mean, obtains front N-1 average channel estimation value that activates the footpath of same position in the window; According to formula
Obtain N average channel estimation value that activates each bar footpath in the window; Wherein, h
K, jBe the j bar channel impulse response directly of k window before the cumulative mean,
Be the average channel estimation value in j bar footpath, j=1 ..., W, k=1 ..., N.That is to say, last activates window and also participates in the process that cumulative mean is processed.
In addition, consider in the same time slot to comprise polytype physical channel, in this case, the method for the embodiment of the invention can also comprise: the step that detects the physical channel type in the described time slot.
When comprising polytype physical channel in the described time slot, S103 is then respectively for dissimilar physical channel, and the channel impulse response that described N activation window is positioned at the footpath of same position carries out cumulative mean, obtains the average channel estimation value.
S104, replace described N channel estimation value that activates the corresponding described same position of window to export as channel estimation value with described average channel estimation value.
Optionally, after S103 obtains the average channel estimation value, also comprise:
According to formula
The average channel estimation value that described N activation window is positioned at the footpath of same position is weighted processing, wherein, i=1 ..., N, Factor
I, jBe i weighted factor that activates window j bar footpath,
Be the average channel estimation value in j bar footpath,
Be i average channel estimation value that activates window j bar footpath after the weighting.
And then, replace described N channel estimation value that activates the corresponding described same position of window to export as channel estimation value the average channel estimation value after the weighting processing.
Wherein, described weighting Factor
I, jBe i footpath signal to noise ratio that activates window j bar footpath; Perhaps, described weighted factor Factor
I, jCarry out value according to default effective diameter interval.For example, can define an effective diameter interval, the footpath within the effective diameter interval, weighted factor is 1; Footpath outside the effective diameter interval, weighted factor are 0.
Need to prove, before with channel estimation value output, can also carry out other subsequent treatment to the channel estimation value that will export among the S104, described subsequent treatment comprises normalization or filters processing such as channel estimation value less than predetermined threshold value, exports the channel estimation value of realistic application requirements.
Channel estimation methods provided by the invention, process rear in order to substitute the original channel estimated value by the footpath of same position in a plurality of activation windows of same time slot being carried out cumulative mean, especially in a time slot, being the situation of a plurality of windows of user assignment, can the establishment noise, can improve the performance that the TD-SCDMA system channel is estimated.
More than be the detailed description that channel estimation methods provided by the present invention is carried out, the below is described in detail channel estimating apparatus provided by the invention.
Embodiment two
Fig. 4 is the channel estimating apparatus schematic diagram that the present embodiment provides, and as shown in Figure 4, channel estimating apparatus of the present invention comprises: initial channel estimation unit 10, activation window detecting unit 20, cumulative mean unit 30 and output unit 40.
Initial channel estimation unit 10 is used for the signal that receives is carried out initial channel estimation, obtains channel estimation value.
The initial channel estimation unit 10 of the embodiment of the invention can but be not limited to obtain initial channel estimation by the B.Steiner algorithm, thereby obtain the initial channel impulse response that length is P=128, formed by K window.
The task of channel estimating estimates all K window (a corresponding K user's) channel impulse response exactly from receive signal, therefore, the channel estimation value that initial channel estimation unit 10 obtains by the B.Steiner algorithm comprises the channel impulse response in K * W bar footpath, wherein, K represents the number of the window that comprises in the time slot, W represents the number in the footpath that comprises in the window, and namely the window of channel estimating is long.
Activate window detecting unit 20 for the described channel estimation value that obtains according to initial channel estimation unit 10, K window in the time slot activated window detect, N that obtains in the described time slot is activated window.Wherein, N is for activating the number of window, N≤K.
Activate window detecting unit 20 can but be not limited to detect by a threshold value is set, arranging of this threshold value can be first calculates the power in 128 footpaths by delivery (be real part square add imaginary part square) computing etc., from 128 footpaths, select a strongest footpath of power, the power of this most powerful path be multiply by a factor (for example 1/16) as the threshold value of setting, judge the quantity that has in the window above the footpath of this threshold value, the window that quantity is met certain requirements detects as activating window again.
Perhaps, activate window detecting unit 20 and select a strongest window of power from 128 footpaths, the power of this window be multiply by a factor as the threshold value of setting, the window that power is surpassed threshold value detects as activating window, etc.
Optionally, activate after the activation window of window detecting unit 20 in obtaining described time slot, also be used for testing result is activated the window sign for the window that activates window arranges.
Cumulative mean unit 30 is used for the channel impulse response that described N the activation window that activation window detecting unit 20 obtains is positioned at the footpath of same position is carried out cumulative mean, obtains the average channel estimation value.
Optionally, cumulative mean unit 30 is according to the described activation window sign that activates 20 settings of window detecting unit, and the channel impulse response that described N activation window is positioned at the footpath of same position carries out cumulative mean, obtains the average channel estimation value.
Particularly, cumulative mean unit 30 is according to formula
The channel impulse response that described N the activation window that activation window detecting unit 20 is obtained is positioned at the footpath of same position carries out cumulative mean, obtains the average channel estimation value in the footpath of same position.
Wherein, h
K, jBe the j bar channel impulse response directly of k window before the cumulative mean,
Be the average channel estimation value in j bar footpath, j=1 ..., W, k=1 ..., N.
In the typical scene of TD-SCDMA system, if high-level signaling is that user configured code channel number M is odd number, front (M-1)/2 window all distributes full 2 code channels so, and last window distributes a code channel.
Optionally, be the situation that user configured code channel number is odd number for high-level signaling, cumulative mean unit 30 can be according to formula
The channel impulse response that front N-1 the activation window that activation window detecting unit 20 is obtained is positioned at the footpath of same position carries out cumulative mean, obtains front N-1 average channel estimation value that activates the footpath of same position in the window; And according to formula
Obtain activating N the average channel estimation value that activates each bar footpath in the window that window detecting unit 20 obtains.Wherein, h
K, jBe the j bar channel impulse response directly of k window before the cumulative mean,
Be the average channel estimation value in j bar footpath, j=1 ..., W, k=1 ..., N.
Perhaps, be the situation that user configured code channel number is odd number for high-level signaling, cumulative mean unit 30 also can be according to formula
The channel impulse response that front N-1 the activation window that activation window detecting unit 20 is obtained is positioned at the footpath of same position carries out cumulative mean, obtains front N-1 average channel estimation value that activates the footpath of same position in the window; And according to formula
Obtain activating N the average channel estimation value that activates each bar footpath in the window that window detecting unit 20 obtains.Wherein, h
K, jBe the j bar channel impulse response directly of k window before the cumulative mean,
Be the average channel estimation value in j bar footpath, j=1 ..., W, k=1 ..., N.
In addition, consider in the same time slot and might comprise polytype physical channel, in this case, channel estimating apparatus in the present embodiment can also comprise: channel type detecting unit (not shown), described channel type detecting unit is connected with cumulative mean unit 30, for detection of the physical channel type in the described time slot.
When described channel type detecting unit detects when comprising polytype physical channel in the described time slot, cumulative mean unit 30 is respectively for dissimilar physical channel, the channel impulse response that described N activation window is positioned at the footpath of same position carries out cumulative mean, obtains the average channel estimation value.
Optionally, the channel estimating apparatus of the embodiment of the invention also comprises: the weighted units (not shown), described weighted units is connected with cumulative mean unit 30, is used for according to formula
The average channel estimation value that described N the activation window that cumulative mean unit 30 is obtained is positioned at the footpath of same position is weighted processing, wherein, i=1 ..., N, Factor
I, jBe i weighted factor that activates window j bar footpath,
Be the average channel estimation value in j bar footpath,
Be i average channel estimation value that activates window j bar footpath after the weighting.
Average channel estimation value after output unit 40 will be processed through described weighted units weighting replaces described N channel estimation value that activates the corresponding described same position of window to export as channel estimation value.
Wherein, the weighting Factor in the described weighted units
I, jBe i footpath signal to noise ratio that activates window j bar footpath; Perhaps, described weighted factor Factor
I, jCarry out value according to default effective diameter interval.For example, can define an effective diameter interval, the footpath within the effective diameter interval, weighted factor is 1; Footpath outside the effective diameter interval, weighted factor are 0.
Need to prove, output unit 40 can also carry out other subsequent treatment to the channel estimation value that will export before with channel estimation value output, described subsequent treatment comprises normalization or filters processing such as channel estimation value less than predetermined threshold value, exports the channel estimation value of realistic application requirements.
Channel estimation methods provided by the invention and device can improve the performance of cdma system (particularly TD-SCDMA system) channel estimating.Especially, when in a time slot, distributing more than 2 code channels, during namely more than a window, can the establishment noise, have obvious performance gain.The improvement of channel estimating performance shows as following aspect for cdma system: 1) for Dedicated Traffic Channel, can reduce Block Error Rate; 2) for the Traffic Channel of HSPA/HSPA+, can improve throughput of system; 3) for control channel, can reduce Block Error Rate, improve the reliability of signaling.
Unit in the device that the present embodiment is mentioned can be realized by logical integrated circuit, and be integrated on the integrated circuit substrate.
The professional should further recognize, unit and the algorithm steps of each example of describing in conjunction with embodiment disclosed herein, can realize with electronic hardware, computer software or the combination of the two, for the interchangeability of hardware and software clearly is described, composition and the step of each example described in general manner according to function in the above description.These functions are carried out with hardware or software mode actually, depend on application-specific and the design constraint of technical scheme.The professional and technical personnel can specifically should be used for realizing described function with distinct methods to each, but this realization should not thought and exceeds scope of the present invention.
The method of describing in conjunction with embodiment disclosed herein or the step of algorithm can use the software module of hardware, processor execution, and perhaps the combination of the two is implemented.Software module can place the storage medium of any other form known in random asccess memory (RAM), internal memory, read-only memory (ROM), electrically programmable ROM, electrically erasable ROM, register, hard disk, moveable magnetic disc, CD-ROM or the technical field.
Above-described embodiment; purpose of the present invention, technical scheme and beneficial effect are further described; institute is understood that; the above only is the specific embodiment of the present invention; the protection range that is not intended to limit the present invention; within the spirit and principles in the present invention all, any modification of making, be equal to replacement, improvement etc., all should be included within protection scope of the present invention.
Claims (14)
1. a channel estimation methods is characterized in that, described method comprises:
The signal that receives is carried out initial channel estimation, obtain channel estimation value, described channel estimation value comprises the channel impulse response in K * W bar footpath, and wherein, K represents the number of the window that comprises in the time slot, and W represents the number in the footpath that comprises in the window;
According to described channel estimation value, K window in the time slot activated window detect, N that obtains in the described time slot is activated window, and wherein, N is for activating the number of window, N≤K;
The channel impulse response that described N activation window is positioned at the footpath of same position carries out cumulative mean, obtains the average channel estimation value;
Replace described N channel estimation value that activates the corresponding described same position of window to export as channel estimation value with described average channel estimation value.
2. method according to claim 1 is characterized in that, the channel impulse response that described N activation window is positioned at the footpath of same position carries out cumulative mean, obtains the average channel estimation value, comprising:
According to formula
The channel impulse response that described N activation window is positioned at the footpath of same position carries out cumulative mean, obtains the average channel estimation value in the footpath of same position;
Wherein, h
K, jBe the j bar channel impulse response directly of k window before the cumulative mean,
Be the average channel estimation value in j bar footpath, j=1 ..., W, k=1 ..., N.
3. method according to claim 1 is characterized in that, when the code channel number of configuration was odd number, the described channel impulse response that described N activation window is positioned at the footpath of same position carried out cumulative mean, obtains the average channel estimation value, comprising:
According to formula
The channel impulse response that front N-1 activation window is positioned at the footpath of same position carries out cumulative mean, obtains front N-1 average channel estimation value that activates the footpath of same position in the window;
According to formula
Obtain N average channel estimation value that activates each bar footpath in the window;
Wherein, h
K, jBe the j bar channel impulse response directly of k window before the cumulative mean,
Be the average channel estimation value in j bar footpath, j=1 ..., W, k=1 ..., N.
4. method according to claim 1 is characterized in that, when the code channel number of configuration was odd number, the described channel impulse response that described N activation window is positioned at the footpath of same position carried out cumulative mean, obtains the average channel estimation value, comprising:
According to formula
The channel impulse response that front N-1 activation window is positioned at the footpath of same position carries out cumulative mean, obtains front N-1 average channel estimation value that activates the footpath of same position in the window;
According to formula
Obtain N average channel estimation value that activates each bar footpath in the window;
Wherein, h
K, jBe the j bar channel impulse response directly of k window before the cumulative mean,
Be the average channel estimation value in j bar footpath, j=1 ..., W, k=1 ..., N.
5. each described method is characterized in that according to claim 1-4, described obtain the average channel estimation value after, also comprise:
According to formula
The average channel estimation value that described N activation window is positioned at the footpath of same position is weighted processing, wherein, i=1 ..., N, Factor
I, jBe i weighted factor that activates window j bar footpath,
Be the average channel estimation value in j bar footpath,
Be i average channel estimation value that activates window j bar footpath after the weighting;
The described average channel estimation value of described usefulness replaces described N channel estimation value that activates the corresponding described same position of window to export as channel estimation value, comprising:
Replace described N channel estimation value that activates the corresponding described same position of window to export as channel estimation value the average channel estimation value after the weighting processing.
6. method according to claim 5 is characterized in that, described weighted factor Factor
I, jBe i footpath signal to noise ratio that activates window j bar footpath;
Perhaps, described weighted factor Factor
I, jCarry out value according to default effective diameter interval.
7. each described method is characterized in that according to claim 1-6, and described method also comprises:
Detect the physical channel type in the described time slot;
When comprising polytype physical channel in the described time slot, the described channel impulse response that described N activation window is positioned at the footpath of same position carries out cumulative mean, obtain the average channel estimation value, comprise: respectively for dissimilar physical channel, the channel impulse response that described N activation window is positioned at the footpath of same position carries out cumulative mean, obtains the average channel estimation value.
8. a channel estimating apparatus is characterized in that, described device comprises: initial channel estimation unit, activation window detecting unit, cumulative mean unit and output unit;
Described initial channel estimation unit, be used for the signal that receives is carried out initial channel estimation, obtain channel estimation value, described channel estimation value comprises the channel impulse response in K * W bar footpath, wherein, K represents the number of the window that comprises in the time slot, and W represents the number in the footpath that comprises in the window;
Described activation window detecting unit for the described channel estimation value that obtains according to described initial channel estimation unit, activates window to K window in the time slot and detects, and N that obtains in the described time slot is activated window, and wherein, N is the number of activation window, N≤K;
Described cumulative mean unit, the channel impulse response that described N of being used for described activation window detecting unit is obtained activation window is positioned at the footpath of same position carries out cumulative mean, obtains the average channel estimation value;
Described output unit is used for replacing described N channel estimation value that activates the corresponding described same position of window to export as channel estimation value with the described average channel estimation value that described cumulative mean unit obtains.
9. device according to claim 8 is characterized in that, described cumulative mean unit is according to formula
The channel impulse response that described N the activation window that described activation window detecting unit is obtained is positioned at the footpath of same position carries out cumulative mean, obtains the average channel estimation value in the footpath of same position; Wherein, h
K, jBe the j bar channel impulse response directly of k window before the cumulative mean,
Be the average channel estimation value in j bar footpath, j=1 ..., W, k=1 ..., N.
10. device according to claim 8 is characterized in that, when the code channel number of configuration was odd number, described cumulative mean unit was according to formula
The channel impulse response that front N-1 the activation window that described activation window detecting unit is obtained is positioned at the footpath of same position carries out cumulative mean, obtains front N-1 average channel estimation value that activates the footpath of same position in the window; And according to formula
Obtain N the average channel estimation value that activates each bar footpath in the window that described activation window detecting unit obtains; Wherein, h
K, jBe the j bar channel impulse response directly of k window before the cumulative mean,
Be the average channel estimation value in j bar footpath, j=1 ..., W, k=1 ..., N.
11. device according to claim 8 is characterized in that, when the code channel number of configuration was odd number, described cumulative mean unit was according to formula
The channel impulse response that front N-1 the activation window that described activation window detecting unit is obtained is positioned at the footpath of same position carries out cumulative mean, obtains front N-1 average channel estimation value that activates the footpath of same position in the window; And according to formula
Obtain N the average channel estimation value that activates each bar footpath in the window that described activation window detecting unit obtains; Wherein, h
K, jBe the j bar channel impulse response directly of k window before the cumulative mean,
Be the average channel estimation value in j bar footpath, j=1 ..., W, k=1 ..., N.
12. each described device is characterized in that according to claim 8-11, described device also comprises: weighted units, described weighted units is connected with described cumulative mean unit, is used for according to formula
The average channel estimation value that described N the activation window that described cumulative mean unit is obtained is positioned at the footpath of same position is weighted processing, wherein, i=1 ..., N, Factor
I, jBe i weighted factor that activates window j bar footpath,
Be the average channel estimation value in j bar footpath,
Be i average channel estimation value that activates window j bar footpath after the weighting;
Average channel estimation value after described output unit will be processed through described weighted units weighting replaces described N channel estimation value that activates the corresponding described same position of window to export as channel estimation value.
13. device according to claim 12 is characterized in that, the weighting Factor in the described weighted units
I, jBe i footpath signal to noise ratio that activates window j bar footpath;
Perhaps, described weighted factor Factor
I, jCarry out value according to default effective diameter interval.
14. each described device according to claim 8-13, it is characterized in that, described device also comprises: the channel type detecting unit, and described channel type detecting unit is connected with described cumulative mean unit, for detection of the physical channel type in the described time slot; When described channel type detecting unit detects when comprising polytype physical channel in the described time slot, described cumulative mean unit is respectively for dissimilar physical channel, the channel impulse response that described N activation window is positioned at the footpath of same position carries out cumulative mean, obtains the average channel estimation value.
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| CN101098208A (en) * | 2006-06-27 | 2008-01-02 | 大唐移动通信设备有限公司 | TD-SCDMA associated detection technology based channel estimation method |
| CN101159445A (en) * | 2007-11-08 | 2008-04-09 | 重庆重邮信科（集团）股份有限公司 | Window accumulation based channel swash response post-processing method and apparatus |
| CN101651466A (en) * | 2008-07-18 | 2010-02-17 | 俊茂微电子（上海）有限公司 | Multi-path tracking method and multi-path tracking device |
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| CN101098208A (en) * | 2006-06-27 | 2008-01-02 | 大唐移动通信设备有限公司 | TD-SCDMA associated detection technology based channel estimation method |
| CN101159445A (en) * | 2007-11-08 | 2008-04-09 | 重庆重邮信科（集团）股份有限公司 | Window accumulation based channel swash response post-processing method and apparatus |
| CN101651466A (en) * | 2008-07-18 | 2010-02-17 | 俊茂微电子（上海）有限公司 | Multi-path tracking method and multi-path tracking device |
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