Feedback-iteration-based OFDM/OQAM (orthogonal frequency division multiplexing/offset quadrature amplitude modulation) system as well as time-frequency synchronization method thereof

Abstract

The invention discloses a feedback-iteration-based OFDM / OQAM (orthogonal frequency division multiplexing / offset quadrature amplitude modulation) system and a time-frequency synchronization method thereof. The system and the method provided by the invention extend a one-step synchronization method of a frequency domain pilot frequency based time-frequency joint estimation method in the traditionalOFDM / OQAM system into a feedback iteration decision method. An initial time offset estimated value is firstly obtained by using time offset estimation; a pilot frequency bit error rate is compared with a preset decision threshold, if the pilot frequency bit error rate is no less than the preset decision threshold, a time offset trial value at the proximity of the initial time offset estimated value is selected to conduct iteration decision value by value until the bit error rate of the pilot frequency data part is less than the decision threshold value, the time offset trial value can be acted as a time offset estimated value for precise timing, and a frequency offset estimated value corresponding to the time offset trial value can be acted as a frequency offset estimated value for precise estimation; and the demodulated data are output in a bit mode, thus the acquisition probability of the time offset estimation in multipath channels can be effectively improved by the processing method.

Description

technical field [0001] The invention belongs to the technical field of mobile communication, and particularly relates to an Orthogonal Frequency Division Multiplexing (OFDM / OQAM, Orthogonal Frequency Division Multiplexing / Offset Quadrature Amplitude Modulation) system and a time-frequency synchronization method thereof. Background technique [0002] Due to the continuous improvement of wireless users' requirements for transmission rate, multi-carrier modulation technology has become the mainstream modulation method of wireless communication, such as traditional Orthogonal Frequency Division Multiplexing (CP-OFDM, Cyclic Prefix-Orthogonal Frequency Division Multiplexing) based on cyclic prefix technology is selected as the key technology in the LTE standard. Compared with CP-OFDM, OFDM / OQAM has higher spectral efficiency and better time-frequency focusing characteristics, and is useful for overcoming inter-symbol interference (ISI, Inter-Symbol Interference) and inter-carrier...

AI Technical Summary

Problems solved by technology

[0034] The purpose of the present invention is to solve the problem that the acquisition probability of the time offset estimation of the existing OFDM / OQAM system based on the time-frequency joint estimation method based on the frequency domain pilot is low, and propose a OFDM / OQAM system based on feedback iteration and its time-frequency synchronization method

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