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Channel Estimation Method for Ofdm System

A channel estimation and channel gain technology, applied in the direction of multi-frequency code system, baseband system components, etc., can solve the problem of low estimation accuracy, achieve the effect of eliminating influence and improving accuracy

Inactive Publication Date: 2014-10-15
UNIV OF ELECTRONICS SCI & TECH OF CHINA
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  • Application Information

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Problems solved by technology

[0005] The purpose of the present invention is to solve the problem that the existing channel estimation methods only eliminate the influence of inter-symbol interference or inter-carrier interference on channel estimation in multi-path channels with fast time and large delay, and propose A Channel Estimation Method for OFDM System

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  • Channel Estimation Method for Ofdm System
  • Channel Estimation Method for Ofdm System
  • Channel Estimation Method for Ofdm System

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Embodiment Construction

[0016] The specific implementation examples of the present invention are given below. It should be noted that the parameters in the examples do not affect the generality of the present invention.

[0017] In the present invention, the data structure sent by the sending end is as figure 1 (a) shown. At the sending end, the time-domain block known sequence is used instead of the cyclic prefix as the guard interval, and the pilot length is greater than the channel normalized maximum delay. Since there is no cyclic prefix protection before the added pilot data and the transmitted OFDM data, the received pilot signal and OFDM data will be subject to inter-symbol interference from adjacent OFDM data or pilot data, such as figure 1 (b) is shown in the shaded part. against figure 1 The data model of the present invention proposes an effective channel estimation method.

[0018] In the system model of the present invention, it is assumed that a multipath channel h=[h with L+1 path...

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Abstract

The invention discloses a channel estimation method of an OFDM system, which specifically includes the steps of initializing, reconstructing a received pilot signal, estimating the mean value of channel gain, estimating channel slope, estimating interference and cyclic iteration. In the method of the present invention, the channel impulse response is modeled as a linear model of fast time-varying large-delay multi-path channel. Firstly, inter-symbol interference is eliminated for the received pilot data, and circular convolution reconstruction is completed. Then, iterative inter-carrier Estimate channel gain mean value and channel slope in the way of interference cancellation. The channel estimation method proposed by the invention can effectively eliminate the influence of inter-carrier interference caused by time-varying and inter-symbol interference caused by multipath time delay on received pilot data, and improve the accuracy of channel estimation.

Description

technical field [0001] The invention belongs to the technical field of mobile communication, and in particular relates to a channel estimation method of an Orthogonal Frequency Division Multiplexing (OFDM) system in which a block pilot is used to replace a cyclic prefix under a fast time-varying channel. Background technique [0002] In the future wireless communication, it is required that the communication system can provide high transmission rate, good mobility, be able to effectively resist large multipath delay, and have high spectral efficiency. However, such a transmission environment usually leads to Time-selective and frequency-selective fading produces inter-symbol interference (Inter-Symbol Interference, ISI) and inter-carrier interference (Inter-Carrier Interference, ICI), which destroys the transmission characteristics of the OFDM system and reduces system performance. Therefore, in order to counteract the impact of fast-changing channels on OFDM systems, effect...

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H04L27/26H04L25/02
Inventor 左海雷霞宋亚敏刘吉张亘
Owner UNIV OF ELECTRONICS SCI & TECH OF CHINA