QR (quick response) decomposition based orthogonal frequency division multiplexing (OFDM) system channel estimation method

Abstract

The invention relates to a QR (quick response) decomposition based orthogonal frequency division multiplexing (OFDM) system channel estimation method. Channel estimation (CE) is a key technology in the OFDM communication system, and CE accuracy directly influences the system communication performance. The invention provides a QR decomposition based channel impact response (CIR) update algorithm. The CIR update algorithm comprises a first step of determining the position of a pilot subcarrier by a list scheduling (LS) algorithm, and acquiring the channel estimation value of the pilot position by a pilot; a second step of reducing noise effect outside an L point by using a discrete fourier transform (DFT) time domain channel estimation algorithm and the characteristic that channel time domain impact response energy mainly focuses on the L point; and a third step of updating the CIR in the L point by using the time domain channel estimation algorithm based on QR decomposition, so as to further lower noise effect in the L point and improve CE accuracy. Under the circumstance of different Doppler frequency shift coefficients, compared with conventional DFT algorithms and linear interpolation algorithms, the improved algorithm lowers the error rate by (1-1.5) dB and improves the performance of the OFDM communication system.

Description

technical field [0001] The present invention relates to the technical field of communication, in particular to an OFDM system channel estimation method. Background technique [0002] OFDM is a wireless communication technology with high transmission rate, which has the advantages of high spectrum utilization rate, strong anti-interference ability, etc., and has good robustness in frequency-domain selective channels. OFDM can simply and effectively eliminate the ISI caused by signal multipath propagation by adding a cyclic prefix CP, and is considered to be one of the most suitable transmission technologies for broadband communications. Channel estimation is an important topic in OFDM communication technology research. Generally speaking, there are two kinds of channel estimation algorithms, one is pilot symbol-assisted channel estimation algorithm, and the other is blind estimation algorithm. Due to the large amount of computation and poor flexibility of the blind estimati...

AI Technical Summary

Problems solved by technology

Compared with the two-dimensional interpolation method, the one-dimensional interpolation method is simple to implement but the accuracy is not high; while the traditional two-dimensional interpolation method has a large amount of calculation, it is difficult to implement and the system delay is large, and it is also difficult Suppresses noise and inter-subcarrier interference

Due to the above reasons, the application of these methods in high-speed data transmission and harsh propagation conditions is limited.

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