OFDM carrier frequency offset estimation method suitable for packet transmission

Abstract

The present invention provides an OFDM carrier frequency offset estimation method for packet transmission, which comprises the following steps: 1) performing IFFT conversion on frequency domain symbols to obtain time domain training symbols of two same repetition modules; 2) adding cyclic prefixes with the length of L on the front of the time domain training symbols to form integral OFDM symbols, and obtaining received OFDM signals carrying frequency offset epsilon through a multipath channel; 3) rotating phases with pi epsilon by N / 2 spaced received sample values in the received OFDM signals to obtain fine frequency offset estimation; 4) performing fine frequency offset compensation on the received OFDM signals to obtain OFDM signals after the compensation; 5) performing FFT conversion on training symbol parts of the compensated OFDM symbols after the cyclic prefixes are removed so as to obtain receiving end modulation frequency domain symbols; 6) detecting peaks of cyclic shift of the receiving end frequency domain symbols and sending end frequency domain symbols to obtain coarse frequency offset estimation; and 7) performing coarse frequency offset compensation on the receiving end modulation frequency domain symbols in a receiving end frequency domain, and summing up the coarse frequency offset estimation and the fine frequency offset estimation to obtain the carrier frequency offset estimation.

Description

technical field [0001] The invention relates to an OFDM carrier frequency offset estimation method suitable for packet transmission in an orthogonal frequency division multiplexing OFDM system, which belongs to the technical field of broadband wireless communication and can be applied to the next generation mobile communication system. Background technique [0002] Orthogonal Frequency Division Multiplexing (OFDM) technology has been extensively studied due to its good anti-multipath interference ability and high spectrum utilization efficiency [document [1] Van Nee R, Prasad R.OFDM for Wireless Multi-media Communications[ M]. Boston, London: Artech House, 2000: 73-93.]. But the OFDM system is very sensitive to frequency offset [literature [2] Moose P H.A technique for orthogonal frequency division multiplexing frequency offset correction [J]. IEEE Trans. on Communications, 1994, 42(10): 2908-2914.]. Because when there is a frequency deviation, the orthogonality between sub...

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Problems solved by technology

Literature [9] Yu Z H, Chen K, Huang Y M, Zhang Yang. OFDM Timing and Frequency Offset Estimation Based on Repeated Training Sequence [C]. International Conference on Wireless Communications, Networking and Mobile Computing, Shanghai, Sep.21-25, 2007 , 264-266] designed a frequency offset estimation algorithm suitable for multipath channels, which improved the estimation accuracy, but the estimation range was still limited

Frequency offset estimation proposed in [[10]Guo Y, Liu G, Ge J H.A novel time and frequency synchronization scheme for OFDMsystems[J].IEEE Trans.on Consumer Electronics, 2008,54(2):321-325.] method, which expands the estimation range, but does not improve the estimation accuracy

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