Based On The Ieee802.16a Ofdm System Channel Estimation Algorithm

Channel estimation technique is one of the key techniques in OFDM systems. Communication systems can enhance their BER performance by using coherence detection only when they could make precise and real-time estimation in fading multipath channel. Recently, more and more researches are focused on channel estimation techniques of OFDM systems. According to the characteristics of various algorithms, we can classify them into three types: pilot-assited channel estimation, blind and semi-blind estimation.This paper mainly on the research of channel estimation algorithms which are suitable for IEEE802.16a OFDM systems. Firstly, this paper set up a baseband link of IEEE802.16a OFDM physical layer. Then get the channel estimation with long preamble in IEEE802.16a OFDM system, and improve the method by suppressing the effect of additive noise, respectively in time domain and frequency domain, thus improve the system performance.As the channel impulse response estimated by DFT-based channel estimation approach appears a spectral leakage, which results in an error floor for the MSE performance. This paper proposed two enhanced DFT interpolation-based channel estimation methods which is based on the Wiener filtering, and can eliminate most of the leakage effect and error floor. The analysis and simulation results show that the proposed methods can achieve a better performance with small complexity increase. At last, this paper designed a new interpolator based on DCT, and this method is applied in channel estimation for IEEE802.16a OFDM system. The simulation result show that the proposed algorithms have simpler implement, better performance than traditional algorithms.