Iterative frequency-domain channel estimation and equalization for single-carrier cooperative transmissions

Cooperative diversity is an effective transmission technique allowing multiple users to create a virtual antenna array although each of them is equipped with single antenna. In this paper, an iterative channel estimation and equalization (ICEE) scheme for single-carrier transmissions is proposed, realizing space-time block code (STBC) with amplify-and-forward (AF) relaying in a distributed fashion. Most existing researchers assume perfect channel information available at the receiver, however, the effect of imperfect channel estimation should be considered for practical applications. In the proposed algorithm, pilot-aided channel estimation (CE) and soft inter-symbol interference (ISI) cancelation with minimum mean squared error (MMSE) filtering are performed iteratively to suppress interferences. An implementation that accounts for imperfect channel estimation is also investigated. The bit error rate (BER) performances and extrinsic information transfer (EXIT) charts are presented for Rayleigh fading channels. Simulation results demonstrate the effectiveness of the proposed algorithm.