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A Multi-ofdm Symbol Channel Estimation Method

A channel estimation and symbol technology, which is applied in the field of channel estimation, can solve problems such as limited performance improvement, subcarrier orthogonality destruction, and channel time-varying is not particularly obvious, so as to improve time-varying, improve estimation performance, and reduce modeling error Effect

Inactive Publication Date: 2017-05-31
UNIV OF ELECTRONICS SCI & TECH OF CHINA
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Problems solved by technology

[0002] The Doppler effect brought about by high-speed movement will seriously reduce the performance of the mobile communication system, resulting in the destruction of the orthogonality between the subcarriers of the Orthogonal Frequency Division Multiplexing (OFDM) system, resulting in subcarriers. Inter Carrier Interference (ICI): Channel estimation is an important part of the front end of the receiver. If the channel information can be accurately estimated, ICI can be suppressed. However, the fast time-varying nature of the channel makes it necessary to acquire channel information Re-discuss
[0003] In high-speed railway wireless communication, the time-varying channel is usually estimated through the equivalent modeling of the base extension model. At present, the channel estimation of the OFDM system with comb pilot structure is based on a single symbol, but when the speed of the mobile terminal decreases In the case of , the time variation of the channel within a single symbol is not particularly obvious. At this time, the base extension model is selected to approximate the channel. Compared with the traditional linear model, the performance improvement is limited, especially when the normalized maximum Doppler frequency shift of the channel is slightly greater than 0.1 Time

Method used

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  • A Multi-ofdm Symbol Channel Estimation Method
  • A Multi-ofdm Symbol Channel Estimation Method
  • A Multi-ofdm Symbol Channel Estimation Method

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Embodiment 1

[0057] The parameters of the OFDM system are set as follows: it is assumed that the OFDM signal modulation mode adopts QPSK modulation, the total number of subcarriers is N=256, and the subcarrier numbers are [1,2...,256]. The cyclic prefix length is set to 10, and digital simulation is carried out on the proposed M (M>1) OFDM symbol joint channel estimation algorithm, where M=4 is assumed. And the example takes a single-path Ricean channel as an example.

[0058] The NMSE(m) of the mth OFDM symbol channel can be expressed as:

[0059]

[0060] The NMSE of a transport block channel consisting of M OFDM symbols can be expressed as:

[0061]

[0062] figure 1 It means that when the signal-to-noise ratio is 30db, single-symbol (M=1) and multi-symbol (M=4) are respectively used as the basic channel estimation unit, and the normalized mean square error of channel estimation increases with the normalized maximum Doppler frequency Situation of shift change. When the normali...

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Abstract

The technical field of mobile communication of the present invention relates in particular to a method for jointly performing channel estimation on a plurality of OFDM symbols under a time-varying channel: establishing a frequency-domain reception vector expression, using MCE-BEM to perform time-domain modeling, and deriving the frequency domain Domain receiving expression, deriving the pilot observation equation of M OFDM symbols per block, using LS criterion to obtain band estimation parameters, and simultaneous equations to obtain the time domain channel matrix. In the method of the present invention, M OFDM symbols are formed into a symbol block for channel estimation. Firstly, time domain modeling is performed to obtain the expression of the time domain channel, and the pilot observation equation derivation of M symbols for each block is completed, and then the LS estimation method is adopted. Estimate the estimated parameters, and finally obtain the time domain channel matrix to complete the estimation. Since multiple symbols are only approximated by rounding up the dimension of the basic model, the modeling error is small, and the number of parameters to be estimated is reduced, and the estimation performance is improved with the same number of pilots.

Description

technical field [0001] The invention relates to the technical field of mobile communication, in particular to a method for jointly performing channel estimation on a plurality of OFDM symbols under a time-varying channel. Background technique [0002] The Doppler effect brought about by high-speed movement will seriously reduce the performance of the mobile communication system, resulting in the destruction of the orthogonality between the subcarriers of the Orthogonal Frequency Division Multiplexing (OFDM) system, resulting in subcarriers. Inter Carrier Interference (ICI): Channel estimation is an important part of the front end of the receiver. If the channel information can be accurately estimated, ICI can be suppressed. However, the fast time-varying nature of the channel makes it necessary to acquire channel information Re-discuss in depth. [0003] In high-speed railway wireless communication, the time-varying channel is usually estimated through the equivalent modeli...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H04L25/02H04L27/26
Inventor 雷霞王崇涵张平平陈帅毛江涛曹海波
Owner UNIV OF ELECTRONICS SCI & TECH OF CHINA
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