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Channel estimating method

A technology of channel estimation and channel frequency domain response, applied in the field of wireless mobile communication, can solve the problems of obvious channel estimation error, large subcarrier error, large channel estimation error, etc., to reduce channel estimation error, weaken influence, and eliminate influence Effect

Active Publication Date: 2008-08-13
NTT DOCOMO INC
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Problems solved by technology

This scheme needs to assume that the timing synchronization is completely accurate in order to determine the position of zero complement in the time domain, but the timing synchronization in the actual OFDM communication system will inevitably have errors
And the channel estimation results obtained by this method still have large errors in the subcarriers near the virtual carrier
[0015] To sum up, since there must be a virtual carrier in the actual OFDM communication system, the channel estimation error obtained by the current DFT-based channel estimation method is relatively large, especially at the position of the subcarrier near the virtual carrier, the channel estimation error more obvious
However, the existing two improved methods still cannot solve the above problems well.

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Embodiment Construction

[0042] The solution of the present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments.

[0043] First, assume that the number of subcarriers in the OFDM system is K, the number of virtual carriers is V, the number of available subcarriers is D, and D is usually an even number, obviously K=V+D. If there is no virtual carrier, the number of equally spaced comb pilots is P, and the pilot interval I = K P , Among them, K, P and I are all powers of 2. If there is a virtual carrier, the number of pilots falling into the range of the virtual carrier and the available subcarriers are P V and P D , the subcarrier is subscripted as k, and k=0, 1, . . . , K-1. If the starting position of the pilot subcarrier is k 0 =0(0≤k0 0 = 2, then the obtained channel frequency domain response estimate needs to be cyclically shifted to the right by two b...

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Abstract

The invention discloses a channel estimation method, comprising: a. carrying out conventional channel estimation on usable pilot frequency located in usable sub-carrier scope, setting virtual channel frequency response estimation for virtual pilot frequency located in virtual carrier scope to assure smooth transition, thus acquiring channel frequency domain response estimations in all pilot frequency positions; b. carrying out inverse Fourier transform for the channel frequency domain response estimations got from step a, to get time domain response estimations; and c. cutting and interpolating zero to the time domain response estimations got from step b, and then carrying Fourier transform to get complete channel frequency domain response estimation. The invention solves the following problems in current technology: large channel estimation error, and obvious channel estimation error in sub-carrier position near virtual carrier. The inventive scheme can effectively reduce, even eliminate the effect of virtual carrier to channel estimation performance, and especially decrease the channel estimation error of sub-carrier position near virtual carrier.

Description

technical field [0001] The invention relates to the technical field of wireless mobile communication, in particular to a channel estimation method. Background technique [0002] Orthogonal frequency division multiplexing (OFDM) technology has the ability to resist inter-symbol interference (ISI) and can provide high spectral efficiency at the same time, so it is regarded as the most likely transmission technology for the next generation of wireless mobile communication systems. It has been widely used in many fields such as digital subscriber loop, digital audio / video broadcasting, wireless local area network and wireless metropolitan area network. [0003] In order to ensure good performance of OFDM communication system in wireless mobile channel environment, it is necessary to estimate the time-varying multipath fading channel as accurately as possible. The quality of channel estimation plays a key role in the performance of OFDM system. [0004] Currently, the channel e...

Claims

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Application Information

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IPC IPC(8): H04L27/26H04B7/04H04B17/00
Inventor 侯晓林张战加山英俊
Owner NTT DOCOMO INC
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