A Novel Channel Estimation Scheme on Amplify-and-Forward Cooperative OFDM-Based Wireless LAN Systems

In this paper, we propose a channel estimation scheme on amplify-and-forward (AF) cooperative orthogonal frequency division multiplexing (OFDM)-based wireless local area network (LAN) systems with one relay. The proposed scheme exploits an Hadamard matrix-based training structure and a maximum ratio combining (MRC)-based estimator for received training signals in two subslots of relaying transmission. The scheme improves estimation accuracy in spite of almost no increase of complexity. We analyze normalized mean square errors (NMSEs) of the scheme and derive its analytical expressions for Rayleigh fading channels. We simulate the NMSE and packet error rate (PER) performance of the conventional and proposed schemes in typical relay location scenarios. The simulation results show that the proposed scheme has better performance than the conventional one in each of the scenarios.