CN1239033C - Discrete Fourier transform based space-time combined inspecting device and method for radio transmission - Google Patents
Discrete Fourier transform based space-time combined inspecting device and method for radio transmission Download PDFInfo
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Abstract
The present invention relates to discrete Fourier transformation based on a space-time combined inspecting device and a method for wireless transmission, particularly to a balanced method and a balanced device applied to the field of wireless mobile communication. The device has the following detection method that: a, after the space-time combination of an estimated impulse response sequence of channels is carried out, a new data sequence h (n) is obtained; b, after the space-time combination is carried out by making use of the estimated channel impulse response sequence of channels and the received data sequence, a new data sequence r#+<lambda>(n) is obtained; c, after the non-normalization discrete Fourier transformation of the r#+<lambda>(n) is carried out, a transformation coefficient R#+<lambda>(k) is obtained; d, the discrete Fourier transformation of the h (n) is carried out, the real part h (k) of the transformed coefficient is taken; e, after the h (k), the r#+<lambda>(k), and the estimated channel noise variance are processed by an equalizer, a new data sequence s#+<lambda> (k) is obtained; f, after the non-normalization inverse discrete Fourier transformation of the sequence S#+<lambda>(k) is carried out, a reconstituted data transmission sequence S#+<lambda>(n) is obtained.
Description
One, technical field:
The present invention relates to a kind of method and apparatus that is applied to the equilibrium in wireless mobile communications field, particularly relate to the method and apparatus of the equilibrium of a kind of spread spectrum radio communications system under the fading channel situation.
Two, background technology:
The mobile communication transmission system because the multipath transmisstion of wireless channel is subjected to its characteristic of channel to influence the as easy as rolling off a log intersymbol interference that causes, when interference causes when having a strong impact on, just must be proofreaied and correct system, and balancing technique mainly is the intersymbol interference that anti-multipath declines.In digital communication system, if the channel frequency response in the system bandwidth is a non-flat forms, on time domain, the impulse response of channel will have the time delay expansion so.This time delay expansion is called channel dispersion again, and all exist the time-division system of channel dispersion to descend with the systematic function that equalizer reduces to cause owing to intersymbol interference.
Two kinds of equilibrium of balanced branch time domain and frequency domain equalizations.Time domain equalization can be divided into linear equalization and nonlinear equalization again.Frequency domain equalization is at filter of receiving terminal serial connection, with the amplitude-frequency and the phase-frequency characteristic of compensate for channel.
Linear equalization algorithm commonly used has three kinds: based on the zero forcing algorithm of minimum peak distortion criterion, based on least mean-square error (MMSE) algorithm and based on the least-squares algorithm of minimal error sum-of-squares criterion.In addition, these three kinds of algorithms all have its non-linear change example-decision feedback equalization (DFE) algorithm, but the most frequently used DFE algorithm that is based on the MMSE criterion.The situation that becomes during for channel parameter the unknown or channel, above-mentioned equalization algorithm has adaptive algorithm separately again: self adaptation zero forcing algorithm, lowest mean square (LMS) algorithm, recurrence least square (RLS) algorithm and self adaptation DFE algorithm.
Though the zero forcing algorithm operand is little, poor-performing, and the restriction of peak distortion is arranged, be very restricted so use.Though LMS algorithm operand is little, performance is relatively good when channel frequency response is comparatively smooth, degradation when channel response is uneven.The characteristics of RLS algorithm are fast convergence rates, the convergence precision height, but computational complexity is higher.The characteristics of decision feedback equalization DFE are that feedback filter can be removed the interference from previous symbol fully so if the front judgement is correct.But if a certain mistake in judgment, propagation then might lead to errors.
Another kind of serves as to optimize the nonlinear equalizer algorithm of criterion to detect error probability.Most typical in such algorithm is maximum-likelihood sequence estimation (MLSE) algorithm and maximum a posteriori probability (MAP) algorithm.
Also there is the shortcoming of two aspects in the MAP algorithm: the one, and it need carry out the forward and backward recursive operation, owing to comprised a large amount of index summation operation in the recursive procedure, so the computing expense is very big; The second, the judgement time delay of MAP algorithm is bigger, has caused very big storage demand thus, and for long frame transmission system, huge memory space is totally unfavorable for reducing the receiver hardware spending.
The MLSE algorithm realizes that by the viterbi algorithm (VA) of classics the status number of VA is relevant with register usually, is fit to little memory span usually.Though in addition the size of channel disturbance how every amount of calculation of staying the routing footpath be constantly just to seem when channel disturbance is very little when that therefore the average computation amount of deciphering is too big
Frequency domain equalization is at filter of receiving terminal serial connection, with the amplitude-frequency and the phase-frequency characteristic of compensate for channel.Such as, be exactly to have adopted frequency domain equalization in OFDM (OFDM) system, so that estimate the frequency response of channel.Owing to adopt discrete Fourier transform (DFT) (DFT) to realize modulation and demodulation, so more responsive to carrier frequency shift, phase noise and non-linear amplification.If will avoid distorted signals and spread spectrum, then need the very big linear amplifier of dynamic range.The basis of OFDM is that subcarrier must satisfy quadrature, if orthogonality worsens, then the performance of whole system can seriously descend, and produces between the distinctive subcarrier of OFDM and crosstalks.In real work,, cause doppler shift effect, thereby influence the carrier frequency orthogonality because the time variation of wireless fading channel tends to cause frequency dispersal.
Three, summary of the invention:
1, technical problem
The objective of the invention is in order to overcome aforesaid problem, space-time joint checkout gear and method based on discrete fourier-transform are provided in a kind of wireless transmission that reduces required computation complexity.
2, technical scheme
Based on the space-time joint checkout gear of discrete fourier-transform, merge cells when this device comprises local pilot cell, pilot/data shunt, channel estimating unit, time-division merge cells, sky, be averaged unit, space merge cells, first discrete Fourier transform unit, second discrete Fourier transform unit, anti-discrete Fourier transform unit, equalizer, the despreading unit that deinterleaves in the wireless transmission of the present invention; Wherein local pilot cell and pilot/data output along separate routes connects the input of channel estimating unit respectively, the merge cells when output of channel estimating unit connects sky respectively, be averaged the unit, and corresponding and time-division merge cells joins, the input of the output termination space merge cells of time-division merge cells, the input of output termination second discrete Fourier transform unit of space merge cells, the input of output termination first discrete Fourier transform unit of merge cells when empty, be averaged the unit, the input of the output termination equalizer of discrete Fourier transform unit, the input of the anti-discrete Fourier transform unit of output termination of equalizer, the deinterleave input of unit of the output termination despreading of anti-discrete Fourier transform unit, the deinterleave output of unit of despreading is the output of this space-time joint checkout gear, the input termination timing signal of local pilot cell; Interactively is between each device: the pilot frequency sequence of exporting along separate routes from pilot/data and the output of the local pilot cell estimation unit of delivering letters respectively estimates channel parameter and noise variance; Merge cells when wherein 6 footpath channel parameter sequences are sent sky earlier send the time-division merge cells to carry out the merging of cross-correlation time with pilot/data data output along separate routes, again amalgamation result when the space merge cells obtains the cross-correlation sky more simultaneously; Merge cells and space merge cells obtain during with sky when empty, and amalgamation result is finished Fourier transform through discrete Fourier transform unit respectively, it exports the single-point equilibrium of sending the MMSE equalizer unit to carry out frequency domain simultaneously with the output that the noise variance that estimates is weighted average weighted average unit, balanced output send anti-discrete Fourier transform module to obtain the time domain data sequence, send subsequent module again.
Its detection method is as follows:
A, merge when the channel impulse response sequence that estimates is carried out sky and obtain autocorrelation sequence h (n),
n＝0，1，…，5；
B, utilize estimate the channel impulse response sequence and the data sequence of reception merge when carrying out sky and obtain cross-correlation sequence r^ (n), n=0,1 ..., L
d-1, L
dDetect the data block length of handling for carry out space-time joint at every turn;
C, r^ (n) is carried out non-normalized discrete Fourier transform (DFT), obtain conversion coefficient R^ (k), k=0,1 ..., L
d-1;
D, h (n) is carried out L
dThe point discrete Fourier conversion, and get the real part H (k) of coefficient after the conversion;
E, obtain a new data sequence S^ (k) through equalizer processes with H (k), R^ (k) and the interchannel noise variance that estimates;
F, new data sequence S^ (k) is carried out non-normalized anti-discrete Fourier transform (DFT), the transmission data sequence s^ (n) that obtains rebuilding, n=0,1 ..., L
d-1.
In the said method among the step a:
(1) the channel impulse response sequence that at every turn estimates is the channel parameter in 6 footpaths;
Merge when (2) the channel impulse response sequence that estimates being carried out sky autocorrelation sequence h (n);
(3) h (n) is the sequence about initial point conjugation symmetry;
(4) channel estimating is the channel estimation methods that adopts based on the cyclic orthogonal experiment pilot frequency sequence
(5) obtain channel estimating for the first time according to criterion of least squares in the channel estimating;
(5) to the first time channel estimating adopt fitting of a polynomial promptly to obtain channel estimating for the second time by the polynomial method that the solving equation group obtains meeting these discrete points by some discrete points;
(7) utilize the channel estimating that obtains for the second time that noise variance is estimated;
(8) above-mentioned channel estimating is carried out at each pilot;
(9) second time that obtains each pilot after the channel estimating, the channel estimating of each sub-slots can on average obtaining by the channel estimating second time of data former and later two pilots adjacent with the control information section;
(10) noise variance of each sub-slots can on average obtaining by the interchannel noise variance that estimates on data former and later two pilots adjacent with the control information section.
The structure of time slot that transmitting terminal adopts is made of one or more sub-slots, and each time slot is by one or more sub-slots G+P+D﹠amp; C and afterbody G+P form, and each sub-slots has recycling-guard G respectively, pilot tone P, user data D, control information C, data and control information section D﹠amp; C, sub-slots afterbody G+P.
The method that merges when empty is:
(3) the 6 footpath channel parameters that respectively each each sub-slots of root antenna estimated are earlier done auto-correlation and are obtained time auto-correlation 6 point sequences;
(4) the 6 new point sequences of 4 corresponding sub-slots of antenna being carried out the space merges and obtains the new autocorrelation sequence h (n) that merges when empty.
The method that merges when empty is:
(1) 6 channel impulse response sequences that at first each sub-slots utilization estimates to every antenna and the pilot/data that the receives data of (201,201,203,204) are along separate routes carried out the time cross-correlation and are merged;
(2) to after the above-mentioned merging respectively 4 sequences of corresponding 4 antennas to carry out addition be that the space merges, obtain new merging cross-correlation sequence r^ (n) when empty, length is L
d, L wherein
dFor sending the length of data sequence.
R^ (n) is carried out non-normalized discrete Fourier transform (DFT), and the step that obtains conversion coefficient R^ (k) is:
(3) r^ (n) is carried out L
dThe discrete Fourier transform (DFT) that point is non-normalized;
(4) non-normalizedly be meant that to add up when summation its value of discrete Fourier transform sequence be not unit 1.
Autocorrelation sequence h (n) is expanded to L
dPoint carries out discrete Fourier transform (DFT) again, and gets the real part H (k) of coefficient after the conversion.
When obtaining a new data sequence S^ (k) through equalizer processes with H (k), R^ (k) and the interchannel noise variance that estimates:
(6) equalizer of Cai Yonging is the least mean-square error equalizer;
(7) equilibrium is carried out at the frequency domain single-point;
Process is when (8) balanced: R^ (k)/(H (k)+N
0), N
0It is the noise variance that estimates;
(9) length of sequence S^ (k) is L
d
Sequence S^ (k) is carried out non-normalized anti-discrete Fourier transform (DFT), during the transmission data sequence s^ (n) that obtains rebuilding, non-normalizedly be meant that its value was not a unit 1 when the anti-discrete Fourier transform sequence that adopts added up summation.
The feature of described equalization methods also is:
Carry out in a sub-slots based on DFT territory single-point equalization methods.
In the said apparatus, the pilot/data branching unit is used for the data that receive are carried out shunt; Channel estimating partly is the channel estimation methods that adopts based on the cyclic orthogonal experiment pilot frequency sequence.At first each pilot is carried out the channel estimating first time of least square, obtain each pilot channel estimating of whole time slot after, utilize the method for fitting of a polynomial to obtain secondary channel estimating to the parameter of estimating again; Utilize secondary channel estimating that noise variance is estimated; Send channel estimating that obtains for the second time and Noise Variance Estimation follow-up unit to use.Local pilot cell is used to store local pilot frequency sequence; The MMSE equalizer unit carries out at the frequency domain single-point.
3, beneficial effect
DFT territory single-point equalization scheme as shown in Figure 1.The main cost that realizes is 2 plural DFT and 1 anti-DFT of plural number (IDFT).Utilize the short characteristics of channel impulse response (estimating 6 footpath channel parameters) simultaneously, the wherein reduction that 1 DFT computing cost can be by a relatively large margin helps hardware and realizes and improve arithmetic speed.Emulation shows: when signal to noise ratio is 6-12dB, adopt DFT territory single-point balancing combine detection method, the performance of BER of native system is better than one of ofdm system more than the magnitude.With reference to figure 5
Four, description of drawings:
Fig. 1 be the low speed mobile object is adopted intermittence the pilot time slot structure schematic diagram.Recycling-guard G is wherein arranged, pilot tone P, user data D, control information C.
Fig. 2 be the middling speed mobile object is adopted intermittence the pilot time slot structure schematic diagram.
Fig. 3 be the high-speed mobile object is adopted intermittence the pilot time slot structure schematic diagram.
Fig. 4 is a concrete device block diagram of the present invention.Wherein have local pilot cell 1, pilot data along separate routes 201,202,203,204, channel estimating unit 301,302,303,304, time-division merge cells 401,402,403,404, space-time merge 503, be averaged unit 502, space merge cells 501, discrete Fourier transform unit 601,602,603, equalizer 701, despreading deinterleave unit 801.
Fig. 5 is the error performance The simulation experiment result figure of the balanced space-time joint detector of DFT territory single-point.
Fig. 6 is the application drawing of the present invention in a kind of baseband transmission system.
Five, embodiment:
The space-time joint checkout gear of discrete fourier-transform in the piecemeal wireless transmission of the present invention, it is characterized in that this device comprise local pilot cell 1, pilot data along separate routes 201,202,203,204, channel estimating unit 301,302,303,304, time-division merge cells 401,402,403,404, space-time merge 503, be averaged unit 502, discrete Fourier transform unit 601,602,603, equalizer 701, despreading deinterleave unit 801; Wherein local pilot cell 1 and pilot data shunt 201,202,203,204 output connects channel estimating unit 301 respectively, 302,303,304 input, channel estimating unit 301,302,303,304 output connects space-time respectively and merges 503, be averaged unit 502, and corresponding and time-division merge cells 401,402,403,404 join, time-division merge cells 401,402,403, the input of 404 output termination space merge cells 501, the input of the output termination discrete Fourier transform unit 602 of space merge cells 501, the input of the output termination discrete Fourier transform unit 601 of space-time merging 503, be averaged unit 502, discrete Fourier transform unit 601, the input of 602 output termination equalizer 701, the input of the output termination discrete Fourier transform unit 603 of equalizer 701, the deinterleave input of unit 801 of the output termination despreading of discrete Fourier transform unit 603, the deinterleave output of unit 801 of despreading is the output of this device, the input termination timing signal of local pilot cell 1.
The purpose, technical solutions and advantages of the present invention are clearer to be described in further detail below in conjunction with the enforcement of accompanying drawing to technical scheme in order to make:
Provided the corresponding structure of time slot that at a slow speed, is adopted when middling speed and high-speed mobile object among Fig. 1, Fig. 2 and Fig. 3 respectively.Each time slot is divided into 1056 chips for long 0.825 millisecond.Each time slot is by one or more sub-slots (D﹠amp; C+P+G) and afterbody form, G represents recycling-guard among the figure, P represents pilot tone, D representative of consumer data, C represent control information.Each G forms by 8 chips among the figure, and each P forms by 24 chips, is not both D﹠amp among Fig. 1; C has 992 chips, each D﹠amp among Fig. 2; C has 480 chips, each D﹠amp among Fig. 3; C has 224 chips.
(1) Fig. 4 is above-mentioned channel estimation methods and DFT territory single-point equalization methods device block diagram, the pattern that adopts 4 antennas of 1 antenna transmission to receive in this installation drawing,
Below in conjunction with structured flowchart, equalization methods is described, step is as follows:
(1) channel estimating part:
Pilot frequency sequence P from pilot/data shunt 201,202,203,204 outputs
m(n) and the output of local pilot frequency sequence unit 1 estimation unit 301,302,303,304 of delivering letters respectively.Wherein channel estimating partly is to adopt aforesaid channel estimation methods based on the cyclic orthogonal experiment pilot frequency sequence.Method to the channel estimating employing fitting of a polynomial first time (being obtained meeting the multinomial of these discrete points by some discrete points by the solving equation group) obtains channel estimating for the second time; The second time that obtains each pilot is after the channel estimating, and the channel estimating of each sub-slots can on average obtaining by the channel estimating second time of data former and later two pilots adjacent with the control information section; Utilize the channel estimating that obtains for the second time that noise variance is estimated; The noise variance of each sub-slots can on average obtaining by the interchannel noise variance that estimates on data former and later two pilots adjacent with the control information section.Each channel estimating unit estimates 6 footpath channel parameter sequences h respectively like this
1(n), h
2(n), h
3(n), h
4(n) and corresponding interchannel noise variance N
01, N
02, N
03, N
04
What adopt in the structured flowchart is the mode of 4 antenna parallel processings, also can adopt time-multiplexed mode in the process that realizes, promptly handles the serial mode of an antenna at every turn and carries out.
Merge the 6 footpath channel parameter sequences h that obtain when (2) channel parameter that estimates being carried out sky
1(n), h
2(n), h
3(n), h
4Merge when (n) sending sky to merge when module 501 is carried out sky and obtain one 6 point sequence
And be conversion h (n)=2*h (n) (n ≠ 0)
(3) rebuild the data sequence that sends:
The argument sequence h of channel transfer functions
1(n), h
2(n), h
3(n), h
4(n) and the data of pilot/data unit 201,202,203,204 output send time merge cells 401,402,403,404 time of carrying out respectively to merge H respectively
1* r
1, H
2* r
2, H
3* r
3, H
4* r
4Computing.R wherein
1, r
2, r
3, r
4It is the data sequence of each antenna reception of pilot/data unit output.Hx (m=1 wherein, 2,3,4 respectively corresponding each antennas) is the circular matrix of following form:
Interchannel noise variance N
01, N
02, N
03, N
04Send and be averaged unit 305 and be averaged computing.
(4) the transmission data sequence of rebuilding being carried out the space merges:
Time merges the output r of module 401,402,403,404
1^ (n), r
2^ (n), r
3^ (n), r
4^ (n) send space merge cells 501 to obtain sequence
Wherein, (()) L
dExpression mould L
dComputing, n=0,1 ..., L
d-1 L wherein
dFor sending the sub-slots length of data sequence, P is channel multi-path number (being taken as 6 herein).
Channel parameter after merging during (5) to sky carries out discrete Fourier transform (DFT):
The output sequence h (n) that merges module 503 when empty send DFT unit 601, also can adopt FFT to realize in specific implementation.
(6) the data reconstruction sequence after the merging of space is carried out discrete Fourier transform (DFT):
The output r^ (n) of space merge cells 501 send DFT unit 602, also can adopt FFT to realize in specific implementation;
(7) the single-point equilibrium of frequency domain:
Get real part H (k) and the output R^ (k) of DFT unit 602 and the output N that is averaged unit 305 of the output factor of DFT unit 601
0Send MMSE equalizer unit 701 to carry out the single-point equilibrium of frequency domain; R^ (k)/(H (k)+N
0),
(8) obtaining of time domain data sequence:
The output S^ (k) of MMSE equalizer send non-normalized anti-discrete Fourier transform module 603 to obtain time domain data sequence s^ (k); In specific implementation, also can adopt IFFT to realize;
(9) subsequent treatment of time domain data sequence
Send subsequent module 801 etc. with s^ (k) sequence.
Fig. 5 is the error performance The simulation experiment result of the balanced space-time joint detector of DFT territory single-point.As can be seen from the figure when signal to noise ratio is 6 one 12dB, adopt DFT territory single-point balancing combine detection method, the bit-rate performance of native system is better than one of ofdm system more than the magnitude.
Fig. 6 is the application of the present invention in a kind of baseband transmission system.
This equalization methods main FPGA that adopts in application realizes.
Claims (10)
1, based on the space-time joint checkout gear of discrete fourier-transform, it is characterized in that this device comprises local pilot cell (1) in a kind of wireless transmission, pilot/data shunt (201,202,203,204), channel estimating unit (301,302,303,304), time-division merge cells (401,402,403,404), merge cells (503) when empty, be averaged unit (502), space merge cells (501), first discrete Fourier transform unit (601), second discrete Fourier transform unit (602), anti-discrete Fourier transform unit (603), equalizer (701), the despreading unit (801) that deinterleaves; Wherein local pilot cell (1) and pilot/data shunt (201,202,203,204) output connects channel estimating unit (301 respectively, 302,303,304) input, channel estimating unit (301,302,303, merge cells when output 304) connects sky respectively (503), be averaged unit (502), and corresponding and time-division merge cells (401,402,403,404) join, time-division merge cells (401,402,403, the input of output termination space merge cells (501) 404), the input of output termination second discrete Fourier transform unit (602) of space merge cells (501), the input of output termination first discrete Fourier transform unit (601) of merge cells (503) when empty, be averaged unit (502), discrete Fourier transform unit (601, the input of output termination equalizer (701) 602), the input of the anti-discrete Fourier transform unit of output termination (603) of equalizer (701), the deinterleave input of unit (801) of the output termination despreading of anti-discrete Fourier transform unit (603), the deinterleave output of unit (801) of despreading is the output of this space-time joint checkout gear, the input termination timing signal of local pilot cell (1); Interactively is between each device: from the pilot/data output of the pilot frequency sequence of (201,202,203,204) output and local pilot cell (1) estimation unit (301,302,303,304) of delivering letters respectively along separate routes, estimate channel parameter and noise variance; Merge cells (503) when wherein 6 footpath channel parameter sequences are sent sky earlier, send time-division merge cells (401,402,403,404) to carry out the merging of cross-correlation time simultaneously with the data output of pilot/data shunt (201,202,203,204) again, again amalgamation result when space merge cells (501) obtains the cross-correlation sky; Merge cells during with sky (503) and space merge cells (501) obtain when empty, and amalgamation result is finished Fourier transform through discrete Fourier transform unit (601,602) respectively, its output send MMSE equalizer unit (701) to carry out the single-point equilibrium of frequency domain with the output that the noise variance that estimates is weighted average weighted average unit (502) simultaneously, balanced output send anti-discrete Fourier transform module (603) to obtain the time domain data sequence, send subsequent module (801) again.
2, a kind of being applicable in the described wireless transmission of claim 1 based on the detection method of the space-time joint checkout gear of discrete fourier-transform is characterized in that its detection method is as follows:
A, merge when the channel impulse response sequence that estimates is carried out sky and obtain autocorrelation sequence h (n),
B, utilize estimate the channel impulse response sequence and the data sequence of reception merge when carrying out sky and obtain cross-correlation sequence r^ (n), n=0,1 ..., L
d-1, L
dDetect the data block length of handling for carry out space-time joint at every turn;
C, r^ (n) is carried out non-normalized discrete Fourier transform (DFT), obtains conversion coefficient R^ (k),
D, h (n) is carried out L
dThe point discrete Fourier conversion, and get the real part H (k) of coefficient after the conversion;
E, obtain a new data sequence S^ (k) through equalizer processes with H (k), R^ (k) and the interchannel noise variance that estimates;
F, new data sequence S^ (k) is carried out non-normalized anti-discrete Fourier transform (DFT), the transmission data sequence s^ (n) that obtains rebuilding, n=0,1 ..., L
d-1.
3, in the wireless transmission according to claim 2 based on the space-time joint detection method of discrete fourier-transform, it is characterized in that in the described said method among the step a:
(1) the channel impulse response sequence that at every turn estimates is the channel parameter in 6 footpaths;
Merge when (2) the channel impulse response sequence that estimates being carried out sky autocorrelation sequence h (n);
(3) h (n) is the sequence about initial point conjugation symmetry;
(4) channel estimating is the channel estimation methods that adopts based on the cyclic orthogonal experiment pilot frequency sequence
(5) obtain channel estimating for the first time according to criterion of least squares in the channel estimating;
(6) to the first time channel estimating adopt fitting of a polynomial promptly to obtain channel estimating for the second time by the polynomial method that the solving equation group obtains meeting these discrete points by some discrete points;
(7) utilize the channel estimating that obtains for the second time that noise variance is estimated;
(8) above-mentioned channel estimating is carried out at each pilot;
(9) second time that obtains each pilot after the channel estimating, the channel estimating of each sub-slots can on average obtaining by the channel estimating second time of data former and later two pilots adjacent with the control information section;
(10) noise variance of each sub-slots can on average obtaining by the interchannel noise variance that estimates on data former and later two pilots adjacent with the control information section.
4, according in claim 2 or the 3 described wireless transmission based on the space-time joint detection method of discrete fourier-transform, it is characterized in that the structure of time slot that transmitting terminal adopts is made of one or more sub-slots, each time slot is by one or more sub-slots G+P+D﹠amp; C and afterbody G+P form, and each sub-slots has recycling-guard G respectively, pilot tone P, user data D, control information C, data and control information section D﹠amp; C, sub-slots afterbody G+P.
5, in the wireless transmission according to claim 2 based on the space-time joint detection method of discrete fourier-transform, the method that merges when it is characterized in that sky is:
(1) the 6 footpath channel parameters that respectively each each sub-slots of root antenna estimated are earlier done auto-correlation and are obtained time auto-correlation 6 point sequences;
(2) the 6 new point sequences of 4 corresponding sub-slots of antenna being carried out the space merges and obtains the new autocorrelation sequence h (n) that merges when empty.
6, according in claim 2 or the 5 described wireless transmission based on the space-time joint detection method of discrete fourier-transform, the method that merges when it is characterized in that sky is:
(1) 6 channel impulse response sequences that at first each sub-slots utilization estimates to every antenna and the pilot/data that the receives data of (201,201,203,204) are along separate routes carried out the time cross-correlation and are merged;
(2) to after the above-mentioned merging respectively 4 sequences of corresponding 4 antennas to carry out addition be that the space merges, obtain new merging cross-correlation sequence r^ (n) when empty, length is L
d, L wherein
dFor sending the length of data sequence.
7, in the wireless transmission according to claim 2 based on the space-time joint detection method of discrete fourier-transform, it is characterized in that r^ (n) is carried out non-normalized discrete Fourier transform (DFT), the step that obtains conversion coefficient R^ (k) is:
(1) r^ (n) is carried out L
dThe discrete Fourier transform (DFT) that point is non-normalized;
(2) non-normalizedly be meant that to add up when summation its value of discrete Fourier transform sequence be not unit 1.
8, in the wireless transmission according to claim 2 based on the space-time joint detection method of discrete fourier-transform, it is characterized in that autocorrelation sequence h (n) is expanded to L
dPoint carries out discrete Fourier transform (DFT) again, and gets the real part H (k) of coefficient after the conversion.
9, in the wireless transmission according to claim 2 based on the space-time joint detection method of discrete fourier-transform, it is characterized in that passing through equalizer processes when obtaining a new data sequence S^ (k) with H (k), R^ (k) and the interchannel noise variance that estimates:
(1) equalizer of Cai Yonging is the least mean-square error equalizer;
(2) equilibrium is carried out at the frequency domain single-point;
Process is when (3) balanced: R^ (k)/(H (k)+N
0), N
0It is the noise variance that estimates;
(4) length of sequence S^ (k) is L
d
10, in the wireless transmission according to claim 2 based on the space-time joint detection method of discrete fourier-transform, it is characterized in that sequence S^ (k) is carried out non-normalized anti-discrete Fourier transform (DFT), during the transmission data sequence s^ (n) that obtains rebuilding, non-normalizedly be meant that its value was not a unit 1 when the anti-discrete Fourier transform sequence that adopts added up summation.
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| CNB031528570A CN1239033C (en) | 2003-08-28 | 2003-08-28 | Discrete Fourier transform based space-time combined inspecting device and method for radio transmission |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN100373840C (en) * | 2005-04-01 | 2008-03-05 | 东南大学 | Method and apparatus for detecting normalized iterative soft interference cancelling signal |
| CN1819569B (en) * | 2006-03-02 | 2011-05-18 | 上海宣普实业有限公司 | Merging and normalizing method and device with down channel estimation in default distributing mode |
| CN100444543C (en) * | 2006-03-31 | 2008-12-17 | 东南大学 | Airspace filter detecting method for multiple antenna radio communication system |
| CN103138854B (en) * | 2011-11-30 | 2014-12-10 | 福建联拓科技有限公司 | Method of detecting subaudio frequency signals and device using the same |
| CN102624659B (en) * | 2012-01-09 | 2015-01-07 | 河南科技大学 | Method for estimating signal-to-noise ratio of multi-antenna ultra-broadband system |
| CN104852879B (en) * | 2015-04-07 | 2017-11-03 | 湖南大学 | A kind of dynamic suppressing method of power line impulsive noise and system |
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