Accurate method for estimating frequency deviation of inseting constant pilot carrier in orthogonal frequency division multiplex system

Abstract

The invention features the following points: for SISO (single-input, single-output) OFDM system and MIMO (multi-input, multi-output) OFDM system, in case of already completing coarse frequency offset estimation and selecting the optimal cyclic prefix interception position, the frequency domain pilot frequency is inserted into the certain sub-carrier wave position of each OFDM symbol, by which the time domain waveform c*(n) is figured out in order to make the waveform correlate with the value of time domain corresponding to the no. j OFDM symbol in the no. i antenna; so the scalar phase angle after correlating can be figured out; combining the antenna combination for the phase angle to get the average phase angle by which the difference between two neighboring OFDM symbols can be acquired, and further more the instantaneous frequency offset estimation value can be acquired; making smoothed filter for the instantaneous value to the accurate frequency estimation value.

Description

technical field [0001] The invention relates to a method for estimating the subcarrier frequency deviation of fractional times between sending and receiving in a single sending and receiving or multiple sending and receiving orthogonal frequency division multiplexing system. Background technique [0002] With the increasing bandwidth requirement in wireless communication, Orthogonal Frequency Division Multiplexing (OFDM) multi-carrier transmission system is attracting a lot of attention in recent years. [0003] Since the Orthogonal Frequency Division Multiplexing OFDM system uses technologies such as inverse Fourier transform and cyclic prefix at the transmitting end and uses Fourier transform demodulation after discarding the cyclic prefix at the receiving end, thereby eliminating inter-symbol interference and making frequency selection Therefore, in practical applications, only a simple frequency domain equalization technique is required to allow high-speed data transmiss...

AI Technical Summary

Problems solved by technology

The frequency deviation between the transmitter and the receiver causes the received signal to shift in the frequency domain. If the frequency deviation is n times the subcarrier spacing, the subcarriers are orthogonal, but the frequency sampling values ​​have shifted by n subcarriers. carrier position

If the carrier deviation is not an integer multiple of the subcarriers, there will be energy "leakage" between the subcarriers, resulting in the destruction of the orthogonality between the subcarriers, thus introducing interference between the subcarriers, making the system The bit error rate performance deteriorates,

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