Study And Improvement Of OFDM System Channel Estimation Based On DCT

As a new generation of mobile communications technologies, Orthogonal frequency division multiplexing (OFDM) technology support high speed data transmission business and efficient spectrum efficiency, It has strong resistance to channel frequency selective decline performance, and can effectively resist multipath interference. If you want to demodulate the original signal accurately at the receiving end, it needs accurate dynamic estimate to channel. Therefore, channel estimation is one of key techniques of OFDM systems. The technology on the OFDM system channel estimation algorithm based on Pilot assistant has become one of the effective ways to channel estimation in a new generation of mobile communication system.In this paper, the OFDM systems principle and channel estimation techniques are studied. Based on the traditional channel estimation algorithm in transform domain of DFT and DCT, an improved DCT transform channel estimation algorithm is put forward based on pilot assistant. Symmetric characteristics of DCT transform is used to eliminate edge effects. It eliminates high frequency noise through the low-pass filter in the DCT transform domain. The pilot quantity can be reduced and the utilization of channel can be improved because the energy of DCT transform is more concentrative than DFT transform; More, the computing complexity can be reduced because DCT transform is a real operator. At the same time algorithm firstly estimates the noise variance, further eliminate noise interference. The simulation results show that the algorithm is superior to the traditional channel estimation algorithm based on DFT and FFT transform in the multi-path fading channel which is available and effective channel estimation algorithm.