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Multistage time domain blind equalization method of OFDM signals

A technology of time-domain equalization and time-domain equalizer, which is applied in multi-frequency code systems, shaping networks in transmitters/receivers, baseband system components, etc., can solve deformation, signal constellation distortion, and affect subsequent signal processing And other issues

Inactive Publication Date: 2014-07-30
BEIJING INSTITUTE OF TECHNOLOGYGY
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Problems solved by technology

[0003] The purpose of the present invention is to solve the problem that the distortion and deformation of the received signal constellation diagram caused by the distortion of the signal in the wireless multipath fading channel environment will affect the subsequent processing of the signal. According to the characteristics of the OFDM signal frame format, a multi-level OFDM signal is proposed. Time Domain Blind Equalization Method

Method used

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  • Multistage time domain blind equalization method of OFDM signals
  • Multistage time domain blind equalization method of OFDM signals
  • Multistage time domain blind equalization method of OFDM signals

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Embodiment

[0065] Suppose the length L of an OFDM symbol S =80, where the cyclic prefix length L CP =16, the length of the frame synchronization symbol is 1 OFDM symbol, and each frame includes 20 OFDM symbols except the frame synchronization symbol, so the total length of a frame is L frm =1680. The wireless channel is a multipath fading channel.

[0066] The processing flow chart of the OFDM signal multistage time domain blind equalization method involved in the method of the present invention is as follows figure 2 as shown,

[0067] Step 1, determine OFDM signal frame format;

[0068] (a) Use the correlation peak search algorithm to search for the frame length L of the OFDM signal frm

[0069] Let the total length of the received signal complex sequence be N=100000, choose a step size τ 1 = 1500 and an estimated maximum frame length M 1 =2000, as formula (1) calculation correlation function is:

[0070] R ...

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Abstract

The invention relates to a multistage time domain blind equalization method of OFDM signals. The method comprises the following steps that the frame format of received signals of a receiving sequence is determined through the correlated peak searching method; frame synchronization symbol information of the OFDM signals is used for completing the first stage of time domain equalization on the received signals, a cyclic prefix sequence of the OFDM signals is used for completing the second stage of time domain equalization on the received signals, and signals after the second stage of time domain equalization are output signals which can be used for subsequent processing of signals. According to the method, in the process of determining equalizer coefficients, inherent repeatability of the frame format of the OFDM signals is fully utilized, and under the condition without prior information of the received signals, signal blind equalization is achieved, and the equalization effect is good; the method has the advantages of being simple in calculation and quick in processing to the OFDM signals with multiple sub carriers.

Description

technical field [0001] The invention relates to a blind equalization method, in particular to a multi-level time-domain blind equalization method for OFDM signals, which belongs to the technical field of communication signal processing. Background technique [0002] Orthogonal frequency-division multiplexing (OFDM: orthogonal frequency-division multiple), as a transmission technology for effectively realizing spectrum resource control, has good performance against narrowband interference and intersymbol interference (ISI). In order to achieve high spectrum utilization, the OFDM+MQAM communication system has become the mainstream of the next generation broadband mobile communication system. In a time-varying channel fading environment, the OFDM+MQAM system can not only adaptively adjust the number of subcarriers, but also dynamically adjust the transmission power, modulation method, and coding method used on each subchannel according to the fading situation. And the spectrum...

Claims

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Application Information

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IPC IPC(8): H04L25/03H04L27/26
Inventor 杨杰袁莹莹张徐绮职如昕
Owner BEIJING INSTITUTE OF TECHNOLOGYGY
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