CN1829206B - A channel estimation method for TD-SCDMA system - Google Patents

A channel estimation method for TD-SCDMA system Download PDF

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Publication number
CN1829206B
CN1829206B CN2005101377504A CN200510137750A CN1829206B CN 1829206 B CN1829206 B CN 1829206B CN 2005101377504 A CN2005101377504 A CN 2005101377504A CN 200510137750 A CN200510137750 A CN 200510137750A CN 1829206 B CN1829206 B CN 1829206B
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channel
pilot
characteristic
pilot frequency
code matrix
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CN2005101377504A
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Chinese (zh)
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CN1829206A (en
Inventor
李立华
杨晓辉
陶小峰
张平
王毅
何丹丹
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北京邮电大学
Lg电子株式会社
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Abstract

The present invention discloses a channel estimation method used in time division synchronous code division multiple access system. It contains equally dividing a time slot to number of time quantum, postulating channel property being constant unaltered in each time quantum, dividing whole pilot frequency sequence to several section having same length, changing intermediate code matrix listing mode, new matrix consisting of divided pilot frequency sequence subsection, utilizing zero forcing algorithm or minimum mean square error algorithm to obtain channel impulse responding estimated value in every time quantum. Said invention matches pilot frequency partial channel estimated value in plurality of continue time slot to calculate non-pilot frequency partial channel property, thereby to obtain channel precise information in whole transmitting data period. Said invention improves system performance in variation channel condition based current TD-SCDMA system.

Description

A kind of channel estimation methods that is used for TDS-CDMA system

Technical field

The present invention relates to a kind of channel estimation methods that is used for TD SDMA (TD-SCDMA) system.

Background technology

TD SDMA (TD-SCDMA) system is based on the 3-G (Generation Three mobile communication system) of time division duplex (TDD) mode, it has used series of key techniques such as uplink synchronous, smart antenna, joint-detection, and the realization of these technology all depends on the rapid and precise estimation to radio channel response.The TD-SCDMA system is provided with the pilot frequency sequence part that is used for carrying out channel estimating in burst (Burst) structure, according to signal that receives and known pilot frequency sequence, can estimate channel impulse response.The channel estimation scheme hypothesis channel of TD-SCDMA system employing at present is invariable in a time slot.Yet continuous increase along with mobile station speed, the envelope correlation of an interior channel fading of time slot descends, and the TDD time slot is used for the pilot frequency sequence of channel estimating, can't accurately reflect this channel variation, this channel estimation value is used for whole time slot, then brings the very big decline of systematic function undoubtedly.

Summary of the invention

At in the existing TD-SCDMA system quick variation channel being difficult to the accurately shortcoming of estimation, the present invention is under the prerequisite that does not change existing TD-SCDMA system frame structure and pilot data, the channel estimation methods of a kind of TD-SCDMA of being used for system has been proposed, to tackle the technical problem that the terminal high-speed motion is brought in the present TDD system.

According to the present invention, a kind of channel estimation methods that is applicable to TDS-CDMA system is provided, comprise step:

(1) time slot is divided into a plurality of time periods, wherein the characteristic of channel remained unchanged in each time period;

(2) pilot portion is divided into a plurality of sections, constructs following intermediate code matrix with equal length:

A m nThe intermediate code matrix that the m section pilot tone that sends for the nth user constitutes:

n=1,2;m=1,...,M

Wherein P is the length of pilot frequency sequence, p (n, and k) (k=1+ (m-1) * Q ..., Q+ (m-1) * Q) be nth user's k frequency pilot sign, M is the maximum quantity of pilot tone segmentation, and W is a channel footpath number, and Q is the length of each section pilot data, wherein Q=P/M;

(3), obtain the channel estimating of pilot portion according to the characteristic of channel of above-mentioned intermediate code Matrix Estimation in each time period;

(4) according to the channel estimating of the described pilot portion that obtains, calculate the characteristic of channel of non-pilot portion, thus the channel estimating in obtaining during the whole transmission data.

According to one embodiment of present invention, set the maximum quantity M of pilot tone segmentation according to the characteristic of channel and system requirements.

Basic design of the present invention is, change the conventional channel algorithm for estimating to the constant hypothesis of channel during transmitting whole pilot tone, proposition is divided into several time periods with a time slot, suppose that the characteristic of channel is invariable in each time period, whole pilot frequency sequence also is divided into the plurality of sections with equal length accordingly, change the arrangement mode of intermediate code (midamble) matrix, new matrix is made of the pilot frequency sequence segment that obtains after cutting apart, utilize zero forcing algorithm or least-mean-square error algorithm, can obtain the channel impulse response estimation value in each time period.Channel estimation value to pilot portion in a plurality of continuous slots carries out the characteristic of channel that The Fitting Calculation goes out non-pilot portion, thus the channel precise information in obtaining during the whole transmission data.

The present invention is based on existing TD-SCDMA system, exchange the very big raising of accuracy of channel estimation for, thereby improved system in the performance that changes fast under the channel condition with the complexity cost of minimum.

Description of drawings

Further describe the present invention with reference to the accompanying drawings and in conjunction with example, wherein:

Fig. 1 illustrates the illustraton of model of the TD-SCDMA system of present employing;

Fig. 2 has compared under the 150km/h speed of a motor vehicle, the characteristic of channel of continuous four time slots is estimated the result who obtains according to channel estimation methods of the present invention and existing channel estimation methods;

Fig. 3 illustrates the illustraton of model of multiaerial system;

Fig. 4 shows Uplink MIMO (many antennas)-JD (joint-detection) link of employing channel estimation methods of the present invention and the performance curve of descending MIMO-JT (uniting transmission) link system's bit error rate under different signal to noise ratio conditions respectively.For the ease of relatively, also show the MIMO-JD/JT performance that adopts the existing channel method of estimation among the figure simultaneously.Hypothesis is in the conventional time slot of TD-SCDMA in the emulation, and except that TS0 was used for broadcast message, TS1, TS2, TS3 were configured to the uplink service time slot, and TS4, TS5, TS6 are configured to the downlink business time slot.The characteristic of channel of 3 ascending time slots channel estimation methods according to the present invention obtains, and the characteristic of channel of 3 descending time slots then utilizes the channel estimation results prediction of ascending time slot to draw.

Embodiment

The present invention adopts existing TD-SCDMA system pilot sequence.In order to improve channel estimated accuracy, revise the constant hypothesis of the whole time slot channel of conventional estimated device, a time slot is divided into a plurality of time periods, suppose what the characteristic of channel remained unchanged in each time period, establishing channel footpath number is W.At first, whole pilot frequency sequence is divided into M segment, utilizes each segment reconstruct intermediate code matrix, the channel impulse response in each time period of part according to ZF or least mean-square error method estimating pilot frequency.Then, utilize the channel estimation value of adjacent a plurality of time-multiplexed pilot parts to carry out the characteristic of channel that the LSM The Fitting Calculation goes out data division, thereby obtain the response characteristic of whole channel.

According to reality and performance requirement, the pilot tone segmentation can be adopted different sizes.Can adopt less M when channel variation is very slow; Adopt bigger M during fast change of channel.

Illustrate the application in the TD-SCDMA system below.

Being without loss of generality, is example with two users in the following analysis, i.e. M among Fig. 1 t=2.Channel maximum diameter number is made as W=8; The hop count that pilot tone is divided is M=8.The length of data is in each section intermediate code sign indicating number: Q=P/M, P=128 are the length of pilot frequency sequence.

The pilot frequency sequence that user side 1 sends be M (1)=[p (1,0), p (1,1) ..p (1, P-1)] T, the pilot frequency sequence that user side 2 sends be M (2)=[p (2,0), p (2,1) ... p (2, P-1)] T, wherein (n k) is nth user's k frequency pilot sign to p, and total number of pilot symbols is P=128.

The signal that the recipient receives can be expressed as:

R=AH+n

R=[r wherein 1, r 2..., r P+W-1] T, r kK symbol representing the recipient to receive.

Channel matrix is:

H = [ h 1,1 1 h 2,1 1 · · · h W , 1 1 · · · h 1 , M 1 h 2 , M 1 · · · h W , M 1 , h 1,1 2 h 2,1 2 · · · h W , 1 3 · · · h 1 , M 2 h 2 , M 2 · · · h W , M 2 ]

h W, m nThe channel response value in expression nth user m section pilot frequency sequence w bar footpath.For example represent first section the channel impulse response of first user, suppose that the value of channel on each footpath remains unchanged h when transmitting this section pilot frequency sequence at pilot frequency sequence 1,1 1h 2,1 1H W, 1 1Be respectively first footpath, second footpath is until the W footpath.

Consider multipath channel, each that receives section pilot frequency sequence all can be added in next section pilot frequency sequence.

The intermediate code matrix that sends can be write as:

A=[A 1A 2]

Wherein: A 1, A 2The intermediate code matrix of difference representative of consumer 1,2

A m nThe intermediate code matrix that the m section pilot tone that sends for the nth user constitutes:

n=1,2;m=1,...,M

Q=P/M is the length of each section pilot data.Matrix A m nIn, each row non-zero equates, all is this section intermediate code pilot data.

Can obtain channel estimating according to the ZF principle is:

H=A +R

A wherein +The pseudoinverse of expression A.

Can get channel estimating according to the MMSE principle is:

H=A T(AA T2I)R

A wherein TThe conjugate transpose of expression A, σ 2Be noise variance, I is the unit diagonal matrix.

Use this algorithm, can obtain the channel estimation value that a plurality of continuous ascending time slots send the pilot frequency sequence time period, these estimated values are carried out match, obtain sending the channel estimating on the data time section between the pilot frequency sequence according to different principles.

Fig. 2 carries out channel estimating to continuous 4 time slots.

The square mean error amount of channel estimating can be calculated by following formula:

E [ | e ( τ ) | 2 ] = E [ | c ( τ ) - c ^ ( τ ) | 2 ]

Wherein c (τ) represents the actual channel value, The expression channel estimation value.Can get through simulation calculation, all square evaluated error of conventional method is E_org=0.0035, and the mean square error of new channel estimation methods is E_est1=3.1038e-004.As seen, adopt new method of estimation that the accuracy of channel estimating is significantly improved.

Above method explanation is all at two one receipts systems, as shown in Figure 1.

In fact this algorithm also can be applicable to mimo system, only need this moment the base station single antenna is expanded to the many antennas in base station, be example with two two receipts systems (referring to Fig. 3):

Two two receipts systems among the figure can regard as by two two one receipts systems and constitute, and system 1 and system 2 are respectively shown in solid line among the figure and dotted line.Two systems carry out channel estimating according to explanation above respectively, then can estimate respectively the channel response H between two transmitting antennas and first reception antenna (1)=[H (1,1), H (2,1)] and two transmitting antennas and second reception antenna between channel response H (2)=[H (1,2), H (2,2)].

When utilizing channel estimation results to carry out joint-detection, channel matrix H can be expressed as

H = H ( 1,1 ) H ( 2,1 ) . . . H ( M t , 1 ) H ( 1,2 ) H ( 2,2 ) . . . H ( M t , 2 ) . . . . . . . . . . . . H ( 1 , M r ) H ( 2 , M r ) . . . H ( M t , M r )

Wherein

Be n unit wherein, n=1 ..., N, m t=1 ..., M t, m r=1 ..., M rN is the symbol numbers of each time slot, M tWith M rRepresent number of transmit antennas and reception antenna number respectively, K is each user's a code channel number, and S is a spreading factor.For if adopt traditional algorithm estimate the result, then have C wherein kBe the frequency expansion sequence of k code channel, Be k code channel m tIndividual transmitting antenna and m rChannel impulse response between the individual reception antenna: And if, then have with new channel estimation method Be k code channel m tIndividual transmitting antenna and m rChannel impulse response between the individual reception antenna on n data character position: Here n represents the position of data symbol, and N is the data symbol number that each time slot of each user transmits.This shows, traditional algorithm supposition channel impulse response is constant in a time slot, and in new algorithm, the channel impulse response in time slot on each data symbol positions is different, will be more accurate so the channel estimation results that the employing new algorithm obtains carries out joint-detection; But the dimension of the channel matrix H in the detection algorithm does not change, and therefore new channel estimation method can not increase the complexity of joint detection algorithm.

The present invention is described in conjunction with instantiation.Yet for those skilled in the art, obviously can be under the situation that does not depart from instruction of the present invention, design of the present invention is applied in the different instantiations goes.The description here is just illustrative, and should not think restrictive fully.Scope of patent protection of the present invention is limited by appended claims, rather than the explanation of front.Therefore all various modification and equivalents that drop in the claim scope all should belong within protection scope of the present invention.

Claims (5)

1. channel estimation methods that is used for TDS-CDMA system comprises step:
(1) time slot is divided into a plurality of time periods, wherein the characteristic of channel remained unchanged in each time period;
(2) pilot portion is divided into a plurality of sections, constructs following intermediate code matrix with equal length:
A m nThe intermediate code matrix that the m section pilot tone that sends for the nth user constitutes:
Wherein P is the length of pilot frequency sequence, p (n, and k) (k=1+ (m-1) * Q ..., Q+ (m-1) * Q) be nth user's k frequency pilot sign, W is a channel footpath number, and M is the maximum quantity of pilot tone segmentation, and Q=P/M is the length of each section pilot data;
(3), obtain the channel estimating of pilot portion according to the characteristic of channel of above-mentioned intermediate code Matrix Estimation in each time period;
(4) according to the channel estimating of the described pilot portion that obtains, calculate the characteristic of channel of non-pilot portion, thus the channel estimating in obtaining during the whole transmission data.
2. method according to claim 1, wherein step (3) also comprises step:
According to the characteristic of channel of above-mentioned intermediate code Matrix Estimation in each time period, utilize the ZF principle to obtain the channel impulse response of pilot portion.
3. method according to claim 1, wherein step (3) also comprises step:
According to the characteristic of channel of above-mentioned intermediate code Matrix Estimation in each time period, utilize the least mean-square error principle to obtain the channel impulse response of pilot portion.
4. method according to claim 1, wherein step (4) also comprises step:
Utilize the channel estimating of the pilot portion in a plurality of continuous slots, carry out the multi-slot match and obtain the characteristic of channel of non-pilot portion.
5. method according to claim 1 is wherein set the maximum quantity M of described pilot tone segmentation according to the characteristic of channel and system requirements.
CN2005101377504A 2005-12-19 2005-12-19 A channel estimation method for TD-SCDMA system CN1829206B (en)

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Families Citing this family (4)

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CN101785208A (en) * 2007-09-18 2010-07-21 Lm爱立信电话有限公司 Reduced interference in an mbms enabled system
CN101505286B (en) * 2009-03-10 2011-10-26 华为技术有限公司 Channel estimation method and apparatus
CN102075220B (en) * 2009-11-23 2013-10-16 中兴通讯股份有限公司 Channel estimating device and method based on time domain noise reduction
CN104426817B (en) * 2013-08-19 2017-11-10 联芯科技有限公司 A kind of channel estimation methods and its device

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN1384627A (en) * 2002-06-10 2002-12-11 北京邮电大学 Channel estimation method for wide-band CDMA system
CN1533191A (en) * 2003-03-21 2004-09-29 乐金电子(中国)研究开发中心有限公司 Adaptive channel evaluating method and device based on expected medium code of construction
CN1567762A (en) * 2003-06-10 2005-01-19 北京邮电大学 A channel estimation method adapted for OFDMA system

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN1384627A (en) * 2002-06-10 2002-12-11 北京邮电大学 Channel estimation method for wide-band CDMA system
CN1533191A (en) * 2003-03-21 2004-09-29 乐金电子(中国)研究开发中心有限公司 Adaptive channel evaluating method and device based on expected medium code of construction
CN1567762A (en) * 2003-06-10 2005-01-19 北京邮电大学 A channel estimation method adapted for OFDMA system

Non-Patent Citations (2)

* Cited by examiner, † Cited by third party
Title
雷鸣, 徐月善, 刘宝玲, 张平.一种提高TDD 系统在快衰落信道中性能的新型时隙结构.北京邮电大学学报26 4.2003,26(4),94-98.
雷鸣, 徐月善, 刘宝玲, 张平.一种提高TDD 系统在快衰落信道中性能的新型时隙结构.北京邮电大学学报26 4.2003,26(4),94-98. *

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