Robust asynchronous STBC transceiver for multiple-access frequency-selective channels

In this paper, we propose a robust STBC transmission scheme to combat the timing synchronization errors over frequency-selective multiple-access channels. First, the equivalent channel model in the presence of timing synchronization errors is derived and we find that the synchronization errors result in an equivalent channel model with larger number of correlated channel taps. Based on this correlated equivalent channel model, the statistical power profile is analyzed and a robust statistical bit loading algorithm is proposed. At the receiver, by exploiting the algebraic structure of the Alamouti STBC, a closed-form expression of the QR receiver is derived which further simplifies computational complexity. Simulation results show that our proposed scheme is robust to timing synchronization errors.