Two schemes of orthogonal space-time block codes for relay networks

In current cooperative communication schemes, to achieve cooperative diversity, synchronization between terminals is usually assumed, which may not be practical. In this paper, shift-orthogonal space-time block codes (SOSTBC) for relay networks without the assumption of synchronization is described. Then based on the set of zero correlation zone (ZCZ) sequence, the definitions of zero cross-correlation zone (ZCCZ) and zero nonperiodic cross-correlation zone (ZNCCZ) sequence set (matrix) were given out, based on which two schemes of SOSTBC are proposed, respectively. Furthermore, systematic constructions and properties of SOSTBC are presented. We also present some simulation results to illustrate the performances of SOSTBC in asynchronous cooperative communications.