An Improved OFDM Channel Estimation Based on CMMB

Abstract

In this paper, the OFDM channel estimate method based on China Mobile Multimedia Broadcasting (CMMB) system is investigated. Wireless communication systems incorporating coherent OFDM requires the estimation and tracking of the time-varying channel response for accurate demodulation of data at the receiver. In pilot-symbol-assisted (PSA) OFDM systems, the MMSE estimator is a good channel estimation technique given that channel statistics are known. However, the major drawback of the MMSE estimator is its high computational complexity, which grows with number of pilots. The LMMSE estimator has lower computational complexity than the MMSE, and better performance than the LS. However, the LMMSE estimator directly applied for CMMB system performances worse than the LS. In comprehensive consideration of performance and computational complexity, an improved method is proposed. Simultaneously, the improved DFT-based estimator is simplified. The simulation is based on CMMB system. Simulation results show that our improved channel estimator performs better than the original one.