Space-Time Coding Scheme for Time-Frequency Asynchronous Two-Way Relay Networks

In this paper, we develop a distributed space-time coding scheme to cope with both time and frequency asynchronism in two-way relay network (TWRN). The convolutional coding is employed to handle multiple timing errors in the networks. We prove that both the cooperative and the multipath diversities can be achieved by linear receivers, e.g., linear zero-forcing (ZF) or minimum mean square error (MMSE) receivers. Moreover, the diversity can be guaranteed almost surely under frequency asynchronism. Numerical results are then provided to corroborate the proposed studies.