CN101547180A - Distributed channel estimation method - Google Patents
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- CN101547180A CN101547180A CN200910082985A CN200910082985A CN101547180A CN 101547180 A CN101547180 A CN 101547180A CN 200910082985 A CN200910082985 A CN 200910082985A CN 200910082985 A CN200910082985 A CN 200910082985A CN 101547180 A CN101547180 A CN 101547180A
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Abstract
The invention discloses a distributed channel estimation method, which belongs to the field of digital communication. The method comprises the following steps: 1) intermittently sending a training sequence by a sending end; 2) converting a received time domain training sequence into a frequency domain training sequence by a receiving end; 3) removing modulation information from the frequency domain training sequence; and 4) performing joint estimation on the module of the frequency domain training sequence after removing the modulation information to obtain the module responding to a frequency domain channel, and performing joint estimation on the phase of the frequency domain training sequence after removing the modulation information to obtain the phase responding to the frequency domain channel. Compared with the prior art, by the method, not only the complexity of the channel estimation is greatly simplified, but also the estimation result has high reliability, stability and precision.
Description
Technical field
The invention belongs to digital communicating field, be specifically related to the distributed channel estimation method under the inapparent channel condition of a kind of time-varying characteristics.
Background technology
Traditional channel estimation methods generally adopted before data message and to insert training sequence or pilot tone is carried out channel estimating, and was the balanced single frame of channel result that estimates with single frame mostly, and this is very effective to the significant wireless channel of time-varying characteristics.Ignored the inapparent channel of time-varying characteristics yet do like this, for example under the wire message way condition, different frames are constantly united the possibility of estimating channel.
Present communication system generally adopts the continuous many groups training sequence of transmission in same frame by channel in order accurately to estimate.Directly addition is average for the real part of the channel that the many groups training sequence in the same frame estimates and imaginary part, and directly addition is average for the real part of the channel that the training sequence of different frame estimates and imaginary part.In the digital communication system, the initial moment deviation of sampling is to cause different channel estimation results constantly can not carry out direct average weighted basic reason with carrier wave start-phase deviation.
For difference channel estimation results is constantly united use, a kind of processing method is: select wherein sometime channel estimation results as the reference point, respectively other channel estimation results are constantly got rid of with respect to initial moment deviation of the sampling of reference point and carrier wave start-phase deviation, at last each result constantly is weighted on average.This different method of channel estimation results Combined Treatment constantly relies on the reliability of reference point very much, there is mistake in case be chosen for the channel estimation results of reference point, then should mistake can spread to each channel estimation results constantly, thereby cause the mistake of last channel estimation results, reliability is low.
Summary of the invention
The objective of the invention is to propose a kind of distributed channel estimation method, it promptly intermittently sends training sequence by distributed channel estimating, and receiving terminal is handled domain channel response respectively according to mould and phase place.Under the inapparent situation of channel time-varying characteristics, it is average that the mould of the domain channel response that different estimations constantly obtain and phase place all can directly be carried out addition, to improve channel estimated accuracy.The method that the present invention proposes has not only been simplified the complexity of channel estimating greatly, and has high estimation accuracy.
The technical scheme of channel estimation methods of the present invention is as follows:
A) transmitting terminal intermittently sends training sequence T (n).The frequency domain presentation of transmitting terminal training sequence is Tf (n)
B) receiving terminal is with the time-domain training sequence Tr that receives
t(n) carry out FFT (Fast-Fourier-Transformation, fast Fourier transform) or DFT (Discrete Fourier Transform, discrete Fourier transform) and obtain receiving terminal frequency domain training sequence Trf
t(n).
C) with receiving terminal frequency domain training sequence Trf
t(n), obtain removing the frequency domain sequence Hf behind the modulation intelligence divided by Tf (n)
t(n).
D) get Hf
t(n) mould obtains R
t(n), be the mould of domain channel response; Get Hf
t(n) phase place obtains θ
t(n), be the phase place of domain channel response.
E) with difference R constantly
T1(n), R
T2(n) ... R
Tk(n) average and obtain R
H(n), promptly different training sequences are constantly united the mould of the domain channel response of estimation; With difference θ constantly
T1(n), θ
T2(n) ... θ
Tk(n) average and obtain
(n), promptly different training sequences are constantly united the phase place of the domain channel response of estimation.Here average is the weighted average of scalar, also can be index filtering, rolling average and other averaging methods.The coefficient of exponent filtering and the length of rolling average can be regulated.
Advantage of the present invention and technique effect are:
1, unites the channel estimation results that has used the different moment, the accuracy of channel estimation height
2, in the channel estimation process, the mould of domain channel response and the phase place of channel all are the scalar weighted averages, realize simple.
3, can adjust average module (coefficient of exponent filtering or the length of rolling average) according to actual needs, between the accuracy of speed of following the tracks of time dependent channel and channel estimation results, compromise.
Description of drawings
The distributed channel that Fig. 1 the present invention proposes estimates that training sequence sends schematic diagram;
The different training sequences constantly that Fig. 2 the present invention proposes are united estimation channel flow chart.
Embodiment
Describe the distributed channel estimation method that is applicable under the inapparent channel condition of time-varying characteristics of the present invention in detail below in conjunction with accompanying drawing, but be not construed as limiting the invention.
As shown in Figure 1, the present invention propose at transmitting terminal, intermittently send training sequence T (n).
Fig. 2 has described the method for the sequence association estimation channel in the different moment.Idiographic flow is:
The 1--transmitting terminal intermittently sends training sequence T (n).The frequency domain presentation of transmitting terminal training sequence is Tf (n)
The 2--receiving terminal is with the time-domain training sequence Tr that receives
t(n) carry out FFT (Fast-Fourier-Transformation, fast Fourier transform) or DFT, obtain frequency domain training sequence Trf
t(n).
3--is with receiving terminal frequency domain training sequence Trf
t(n), obtain removing the frequency domain sequence Hf behind the modulation intelligence divided by Tf (n)
t(n).
4--gets Hf
t(n) mould obtains R
t(n), be the mould of domain channel response; Get Hf
t(n) phase place obtains θ
t(n), the phase place of domain channel response.
5--is with difference R constantly
T1(n), R
T2(n) ... R
Tk(n) average and obtain R
H(n), promptly different training sequences are constantly united the mould of the domain channel response of estimation; With difference θ constantly
T1(n), θ
T2(n) ... θ
Tk(n) average and obtain
(n), promptly different training sequences are constantly united the phase place of the domain channel response of estimation.Here average is the weighted average of scalar, can be index filtering, rolling average and other averaging methods.Here different estimated results are constantly done average prerequisite and are, different scopes constantly are in the inapparent scope of channel variation.
Enumerate a specific embodiment below, the distributed channel estimation approach that the present invention proposes is described.This embodiment unites the estimation channel with the training sequence in four moment and describes.
Transmitting terminal intermittently sends training sequence T (n).The frequency domain presentation of transmitting terminal training sequence is Tf (n).If moment t
1The training sequence that receives is Tr
T1(n), moment t
2The training sequence that receives is Tr
T2(n), moment t
3The training sequence that receives is Tr
T3(n), moment t
4The training sequence that receives is Tr
T4(n).
The receiving sequence in four moment is FFT respectively, obtains Trf
T1(n), Trf
T2(n), Trf
T3(n), Trf
T4(n).
With Trf
T1(n), Trf
T2(n), Trf
T3(n), Trf
T4(n), obtain removing the sequence Hf behind the modulation intelligence respectively divided by Tf (n)
T1(n), Hf
T2(n), Hf
T3(n), Hf
T4(n).
Suppose that average module employing length is four rolling average.
The mould of then uniting the domain channel response of estimation is:
The phase place of the domain channel response of associating estimation is:
Although disclose specific implementation method of the present invention and accompanying drawing for the purpose of illustration, its purpose is to help to understand content of the present invention and implement according to this, but it will be appreciated by those skilled in the art that: without departing from the spirit and scope of the invention and the appended claims, various replacements, variation and modification all are possible.The present invention should not be limited to this specification and the disclosed content of accompanying drawing, and the scope of protection of present invention is as the criterion with the scope that claims define.
Claims (10)
1. a distributed channel estimation method the steps include:
1) transmitting terminal intermittently sends training sequence;
2) receiving terminal is converted to frequency domain training sequence with the time-domain training sequence that receives;
3) modulation intelligence of removal frequency domain training sequence;
4) mould of the frequency domain training sequence behind the removal modulation intelligence is united the mould of estimating to obtain domain channel response; Phase place to the frequency domain training sequence behind the removal modulation intelligence is united the phase place of estimating to obtain domain channel response.
2. the method for claim 1 is characterized in that adopting the fast Fourier transform method that time-domain training sequence is converted to frequency domain training sequence.
3. the method for claim 1 is characterized in that adopting the discrete Fourier transform method that time-domain training sequence is converted to frequency domain training sequence.
4. as claim 1 or 2 or 3 described methods, the method that it is characterized in that removing the modulation intelligence of described frequency domain training sequence is: with the receiving terminal frequency domain training sequence divided by the frequency domain presentation that sends training sequence.
5. the method for claim 1 is characterized in that the mould computational methods of described domain channel response are: for the frame that current time receives, at first remove except that the mould of the frequency domain training sequence behind the modulation intelligence mould as this moment domain channel response; To uniting estimation, obtain the mould of domain channel response then by the mould of each different domain channel response that frame obtained that receive constantly.
6. the method for claim 1, the phase calculation method that it is characterized in that described domain channel response is: for the frame that current time receives, at first remove except that the phase place of the frequency domain training sequence behind the modulation intelligence phase place as this moment domain channel response; To uniting estimation, obtain the phase place of domain channel response then by the phase place of each different domain channel response that frame obtained that receive constantly.
7. as claim 1 or 5 or 6 described methods, it is characterized in that described the associating is estimated as the average or scalar weighted average of direct scalar.
8. as claim 1 or 5 or 6 described methods, it is characterized in that described the associating is estimated as rolling average or exponent filtering.
9. method as claimed in claim 8 is characterized in that the adjustable length of described rolling average.
10. method as claimed in claim 8 is characterized in that the coefficient of described exponent filtering is adjustable.
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| CN2009100829856A CN101547180B (en) | 2009-04-28 | 2009-04-28 | Distributed channel estimation method |
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101867389A (en) * | 2010-04-28 | 2010-10-20 | 复旦大学 | Down link secondary synchronous channel (S-SCH) detection method of 3GPP-LTE (3rd Generation Partner Project-Long Term Evolution) system |
| CN104202282A (en) * | 2014-06-12 | 2014-12-10 | 北京大学 | Method and system of distributed channel estimation based on phase compensation |
| CN107276930A (en) * | 2016-04-08 | 2017-10-20 | 深圳超级数据链技术有限公司 | Channel estimation methods and device |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1791077A (en) * | 2005-12-29 | 2006-06-21 | 上海贝豪通讯电子有限公司 | Time-domain and frequency-domain combined channel estimating method |
| CN101312597B (en) * | 2008-05-08 | 2011-11-16 | 北京创毅视讯科技有限公司 | Channel estimation unit and channel estimation method |
-
2009
- 2009-04-28 CN CN2009100829856A patent/CN101547180B/en active Active
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101867389A (en) * | 2010-04-28 | 2010-10-20 | 复旦大学 | Down link secondary synchronous channel (S-SCH) detection method of 3GPP-LTE (3rd Generation Partner Project-Long Term Evolution) system |
| CN101867389B (en) * | 2010-04-28 | 2013-07-31 | 复旦大学 | Down link secondary synchronous channel (S-SCH) detection method of 3GPP-LTE (3rd Generation Partner Project-Long Term Evolution) system |
| CN104202282A (en) * | 2014-06-12 | 2014-12-10 | 北京大学 | Method and system of distributed channel estimation based on phase compensation |
| CN107276930A (en) * | 2016-04-08 | 2017-10-20 | 深圳超级数据链技术有限公司 | Channel estimation methods and device |
| CN107276930B (en) * | 2016-04-08 | 2021-08-03 | 深圳光启合众科技有限公司 | Channel estimation method and device |
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| Publication number | Publication date |
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| CN101547180B (en) | 2012-04-25 |
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Application publication date: 20090930 Assignee: BEIJING HANNUO SEMICONDUCTOR TECHNOLOGY CO., LTD. Assignor: Peking University|Beijing three ladder network technology Co., Ltd. Contract record no.: 2017990000150 Denomination of invention: Distributed channel estimation method Granted publication date: 20120425 License type: Exclusive License Record date: 20170425 |