Channel response estimation method of OFDM system and correcting system

Abstract

The invention discloses an OFDM system channel response estimation method and a correction system thereof, belonging to wireless communication technical field. The method includes the following steps: calculating to obtain the channel response estimation value Hest(k1) according to the frame prior to the current data frame, processing FFT treatment to the short training sequence of the data frame to obtain the frequency domain sequence Rsync(k2) of the data frame, and removing the magnitudes and the phase information of the frequency domain sequence Rsync(k2) at each frequency point to obtain the channel response estimation value Hsync(k2); according to the channel response estimation value Hest(k1) and the channel response estimation value Hsync(k2), calculating the sampling start time deviation difference Delta Epsilon<1,2>sto,est and the carrier wave start phase deviation difference Delta Phi<1,2>cpo,est of the Hest(k1) and the Hsync(k2), and conducting phase correction to the channel response estimation value Hest(k1) by using the deviation difference Delta Epsilon<1,2>sto,est and the deviation difference Delta Phi<1,2>cpo,est to obtain a channel response estimation value H`est(k1)which is used in balanced calculation of the current frame. The OFDM system channel response estimation method and the correction system enable the channel response estimation values obtained by all the frames to be used by each other, and can effectively improve the bit error rate performance of the system and enable the transmission efficiency of the system to be improved by a large margin.

Description

technical field [0001] The present invention relates to OFDM (Orthogonal Frequency Division Multiplexing, Orthogonal Frequency Division Multiplexing) technology in the field of wireless communication, in particular to a channel response estimation method and correction system of an OFDM system. Background technique [0002] In recent years, in order to adapt to the two-way transformation of cable TV network and the application requirements of broadband communication network, digital TV network and next-generation Internet "triple play", communication system technology solutions based on coaxial cable transmission have become one of the research hotspots, such as high System solutions such as performance network over coax (HiNOC), WiFi frequency reduction, and multimedia over coax alliance (MoCA) have been proposed one after another. Compared with the wireless communication environment, the wired channel has the characteristics of insignificant time-varying characteristics. ...

AI Technical Summary

Problems solved by technology

However, in an actual communication system, the D / A converter at the sending end and the A / D converter at the receiving end use their own clocks, and the clock edges of the two clocks are not aligned, so that there is a sampling gap between the sending signal and the receiving signal. start time deviation

In addition, the modulator at the transmitting end and the demodulator at the receiving end use different carrier generators, and the starting phases of the two carriers are also inconsistent, thus introducing a carrier starting phase deviation in the transmission signal

Since the physical layer frames transmitted at different times have different sampling start time deviations and carrier start phase deviations, the channel response estimates obtained at the receiving end of the OFDM system cannot be directly used for each other.

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