Channel Estimation Technology For OFDM Systems Based On Compressed Sensing

This paper mainly studies the channel estimation technology for OFDM system. Main contributions are as follows.(1)Researches on channel time delay estimation algorithms for OFDM system. This paper proposes an improved time delay estimation algorithm, where the advantages of conventional PARK algorithm and REN algorithm are combined. The proposed algorithm has better performance and significantly eliminates the sidelobes interference, compared with the conventional symbol synchronization algorithms through simulations.(2)This paper proposes an improved compressed sensing channel estimation algorithm based on Cyclic Difference Sets (CDS) pilot. The algorithm further utilizes the channel delay distribution property to improve the performance of channel estimation. Simulation results show that the improved algorithm has better performance.(3)Through taking the channel sparsity and time correlation into consideration, this paper proposes an OFDM compressed sensing channel estimation scheme based on Joint Sparse Model (JSM). The key idea of this scheme is to estimate the channel parameters through pilots in multiple OFDM symbols, where the channel parameters are assumed to change slowly. We investigate the estimation performance under different channel Doppler frequency through simulations. Simulation results show that the proposed JSM-based CS channel estimation scheme has better channel estimation performance than the conventional LS based channel estimation algorithm and single OFDM symbol based CS channel estimation algorithm.