Integral multiple frequency offset estimation method of OFDM (orthogonal frequency division multiplexing) system with residual time bias

An integer frequency offset and communication system technology, applied in the field of communication, can solve the problems of high system overhead, reduced spectrum utilization rate of the communication system, low accuracy and robustness of integer frequency offset estimation, etc. Frequency selective fading and residual time offset are very sensitive, and the effect of improving spectrum utilization

Inactive Publication Date: 2011-11-09
XIDIAN UNIV
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Problems solved by technology

The disadvantage of this method is that the system overhead caused by the training sequence is too large, which reduces the spectrum utilization of the communication system
The disadvantage of this method is that the channel frequency impulse response between a

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  • Integral multiple frequency offset estimation method of OFDM (orthogonal frequency division multiplexing) system with residual time bias
  • Integral multiple frequency offset estimation method of OFDM (orthogonal frequency division multiplexing) system with residual time bias
  • Integral multiple frequency offset estimation method of OFDM (orthogonal frequency division multiplexing) system with residual time bias

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[0032] The present invention will be further described below with reference to the drawings.

[0033] The present invention completes the process of estimating the integer frequency offset with the remaining time offset in the OFDM system as figure 1 As shown, the implementation steps are as follows:

[0034] Step 1. Generate training sequence

[0035] 1a) Generate random sequence: The signal processor of the communication system generates a binary random sequence of length 2N according to equal probability of 0, 1, where N is the number of points for the system to perform fast Fourier transform, which is set by the OFDM parameter of the 802.11e standard It is required to determine that the value of N in the embodiment of the present invention is 512;

[0036] 1b) Perform QPSK constellation mapping on the binary random sequence according to the mapping mode of [1+j, 1-j, -1-j, -1+j] to obtain a local frequency domain training sequence of length N, and train the local frequency domain ...

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Abstract

The invention discloses an integral multiple frequency offset estimation method of an OFDM (orthogonal frequency division multiplexing) system with residual time bias, which solves the problems of low utilization rate of channel frequency spectrum and low accuracy in integral multiple frequency offset estimation in the prior art. The method specifically comprises the following steps of: (1) generating a training sequence according to performance requirement of the system, and storing the training sequence in a transmitting terminal and a receiving terminal; (2) performing fast Fourier transform on a received signal of which cyclic prefix is removed, thus obtaining a frequency domain signal of the received signal; (3) generating a cross-ambiguity function according to the receiving end frequency domain signal and a local training sequence; (4) forming a two-dimensional moment matrix according to Doppler slices of the cross-ambiguity function; and (5) traversing the two-dimensional moment matrix in the whole time delay and the frequency offset range to obtain an integral multiple frequency offset estimation value and a residual time bias estimation value. The method provided by the invention has the advantages of low system overhead, high accuracy in integral multiple frequency offset estimation and strong capability in resisting frequency-selective fading.

Description

technical field [0001] The invention belongs to the field of communication technology, and further relates to an integer multiple frequency offset estimation method with residual time offset in an Orthogonal Frequency Division Multiplexing (OFDM) system in ultra-high-speed wireless mobile communication, which can be used for ultra-high-speed wireless In the time-frequency synchronization module of the mobile communication system, the integer multiple frequency offset estimation under the condition of remaining time offset in the synchronization system is realized. Background technique [0002] OFDM technology has the advantages of strong anti-multipath fading ability, high spectrum utilization rate and high data transmission rate, and has been widely used in military and civil communication systems. One of the main disadvantages of OFDM technology is that it is very sensitive to the frequency offset of the carrier, especially when the Doppler frequency offset generated by th...

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Application Information

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IPC IPC(8): H04L27/26H04L25/02H04L25/03
Inventor 李丹萍张海林李勇朝王晓元吴蕊琴
Owner XIDIAN UNIV
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