Synchronous acquisition method and receiving end equipment of OFDM (orthogonal frequency division multiplexing) signal

Abstract

The invention provides a synchronous acquisition method and receiving end equipment of an OFDM (orthogonal frequency division multiplexing) signal. The synchronous acquisition method comprises the following steps of multiplying the front or rear half of the OFDM signal, which has a length of N, by a pseudo noise sequence at a receiving terminal to calculate a timing metric function; multiplying the radication of a power factor by a splicing sequence to obtain a training sequence in the OFDM signal, wherein a front son sequence multiplies by the pseudo noise sequence to obtain the splicing sequence; searching the maximum value when the timing metric function exceeds a reserved threshold, wherein a sampling point which corresponds to the maximum value is a timing estimation point; determining a decimal frequency deviation estimated value at the timing estimation point, and carrying out decimal frequency deviation compensation on the sequence which is behind the timing estimation point and has the length of N in the OFDM signal; and carrying out circulating shift cross-correlation on the sequence subjected to decimal frequency deviation compensation and the training sequence in a time domain, searching for a maximum value to obtain an integer frequency offset estimated value. The synchronous acquisition method and the receiving end equipment provided by the invention have the advantages that the exact and rapid synchronous acquisition is realized.

Description

technical field [0001] The invention relates to the communication field, in particular to a method for synchronous acquisition of an orthogonal frequency division multiplexing signal and a receiving end device. Background technique [0002] Orthogonal frequency division multiplexing (OFDM) is a multi-carrier technology. The entire wireless channel is divided into multiple sub-channels. Each sub-channel transmits a carrier signal, and each sub-carrier carries information about the carrier. It has high spectrum utilization rate, simple implementation, adaptive modulation method, and strong anti-multipath fading ability, and is being used more and more widely in modern wireless communication. Many wireless standards, such as digital audio broadcasting (DAB), digital video broadcasting (DVB-T), local area network standard (IEEE802.11), dedicated short-range communication technology (DSRC), etc., all use OFDM as the physical layer communication technology, and because of its The...

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Literature [1] (F.Wu, M.A.Abu-Rgheff, Time and Frequency Synchronization Techniques for OFDM Systems operating in Gaussian and Fading Channels: A Tutorial, Proc. of the 8th Annual Postgraduate Symposium on the Convergence of Telecommunications, Networking a Broadcasting (PGNET ), June2007) used the timing algorithm proposed by Seung, which has a sharp peak and fewer side lobes, but the frequency offset estimation is performed in the frequency domain, which requires FFT transformation, which increases the complexity of the algorithm

Literature [2] (Zhu Yan, Zhang Huisheng, Luo Yanbu. OFDM time-frequency synchronization algorithm based on CAZAC sequence [J]. Computer Simulation, 2009, v.2611:130-133) uses CAZAC (Const Amplitude Zero Auto-Correlation, Constant envelope zero autocorrelation) sequence of strong correlation, using the weighted method, accurate timing, but the integer frequency offset estimation method is affected by the hardware quantization process

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