OFDM carrier frequency offset estimation method suitable for packet transmission

A technology of carrier frequency offset and packet transmission, applied in multi-carrier systems, multi-frequency code systems, shaping networks in transmitters/receivers, etc., can solve problems such as limited estimation range, no improvement in estimation accuracy, and expansion of estimation range

CN101588338BInactive Publication Date: 2011-08-17SHANDONG UNIV
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Patent Information

Authority / Receiving Office
CN · China
Patent Type
Patents(China)
Current Assignee / Owner
Publication Date
2011-08-17
Estimated Expiration
Not applicable · inactive patent

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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.
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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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Embodiment Construction

[0067] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0068] Aiming at the contradiction between estimation accuracy and estimation range in carrier frequency offset estimation, the invention proposes an effective carrier frequency offset estimation scheme.

[0069] In the fine frequency offset estimation, the present invention additionally uses the redundant information of the cyclic prefix, that is, the correlation between the cyclic prefix and the corresponding sequence of the first part in the training symbol, which obviously improves the estimation accuracy of the carrier frequency offset. And the combined use of the fine frequency offset estimation in the time domain and the coarse frequency offset estimation in the frequency domain makes the estimation range of the carrier frequency offset expand to the whole signal bandwidth. Therefore, the contradiction between estimation accuracy and estimation r...