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Channel estimation method for MIMO OFDM system

A technology of orthogonal frequency division and channel estimation, applied in orthogonal multiplexing system, multi-frequency code system, multiplexing communication, etc., can solve the problems of high algorithm complexity and poor performance

Inactive Publication Date: 2009-01-07
ZTE CORP
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The LS channel estimation algorithm is simple, but it is greatly affected by Gaussian white noise and Inter Carrier Interference (ICI), and its performance is worse than that of MMSE channel estimation; MMSE channel estimation has a good suppression effect on Gaussian white noise and ICI. It is better than LS channel estimation, but the algorithm complexity is high, and accurate channel statistical characteristics need to be known, which is impossible to achieve in practice

Method used

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  • Channel estimation method for MIMO OFDM system
  • Channel estimation method for MIMO OFDM system
  • Channel estimation method for MIMO OFDM system

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Embodiment 1

[0035] In an embodiment of the present invention, a MIMO OFDM channel estimation method is provided, wherein ideal synchronization or correct synchronization is assumed, and the time domain LS algorithm of Discrete Hartley Transform (DHT) is used to implement the present invention.

[0036] In the present embodiment, do DHT to the received time-domain signal, instead of commonly used discrete Fourier transform (DFT), utilize the mapping relation of DHT and DFT, construct the orthogonal matrix (matrix D hereinafter) of real number, and It is not the complex unitary matrix (matrix B in the above) in the traditional algorithm, and the channel state information is calculated by using the transpose of the D matrix and the signal output of the Hartley field.

[0037] Specifically, such as figure 2 As shown, the MIMO OFDM channel estimation method according to the embodiment of the present invention includes:

[0038]Step S202 (step 1), after the received signal is synchronized, a ...

Embodiment 2

[0054] In the process of channel estimation using the pilot, it is necessary to perform a difference algorithm on the pilot points, and the DHT-based interpolation algorithm is a non-linear difference.

[0055] Such as image 3 As shown, the DHT-based interpolation process according to this embodiment includes:

[0056] Step S302 (step A), obtain the channel frequency response H of the pilot point p ;

[0057] Step S304 (step B), the discrete Hartley transform of M point is done to the channel frequency response of pilot point:

[0058] H ^ p ( m ) = 1 N Σ k = 0 M - 1 H p ( k ) cas ...

example 1

[0065] First, insert the pilot signal in the transmitted data, and for the channel that changes slowly, use Figure 4 In the shown block pilot insertion, the insertion method on each antenna is the same (assuming that there are two transmitting antennas).

[0066] The pilot sequence in this example selects PSP, and the design method is as follows: Suppose there is a pilot sequence with a length of M, then X n ( p ) = exp ( - 2 πj · p · n / N t ) , Wherein, n=0,..., M-1, p=0,..., Nt-1, and j represents a complex number symbol.

[0067] The pilot frequency and data enter the channel after OFDM modulation, and the time domain signal Y is obtained at the receiving end. Acc...

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Abstract

The invention provides a channel estimation method of an MIMO OFDM system, and the channel estimation method comprises the following steps: step one, a received signal is synchronized, and a time-domain signal after the synchronization is generated; step two, discrete Hartley transformation is carried out on the time-domain signal, and a Hartley-domain signal is output; step three, a real number orthogonal matrix is constructed by utilizing the mapping relationship between discrete Fourier transformation and the discrete Hartley transformation; step four, the time-domain channel shock response is estimated through the transpose of the constructed real number orthogonal matrix and the output Hartley-domain signal. The invention further provides a method for interpolating pilot frequency points based on the discrete Hartley transformation. The contradiction which exists between the estimation precision and the realization complexity of the existing channel estimation method of the MIMO OFDM communication system can be overcome through the invention.

Description

technical field [0001] The present invention relates to the information wireless transmission technology in the mobile communication system, more specifically, relates to the multiple input multiple output (Multiple Input Multiple Output, referred to as MIMO) orthogonal frequency division multiplexing (Orthogonal Frequency Division Multiplexing, referred to as OFDM) in the field of communication Systematic channel estimation method. Background technique [0002] OFDM technology is widely used in many broadband data communication systems (for example, DAB (Digital Audio Broadcast, digital audio broadcasting), DVB (Digital Video Broadcast, Digital Video Broadcasting), and HDTV (High Definition Television, high-definition digital television)) and wireless local area network standard WLAN IEEE802.11a / g, on the other hand, under flat fading channel conditions, MIMO technology can provide diversity gain and multiplexing gain , can increase the system capacity. Since OFDM technol...

Claims

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Application Information

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IPC IPC(8): H04L25/02H04L27/26H04B1/707H04J11/00
Inventor 王衍文郝东来郭阳
Owner ZTE CORP
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