Distributed Closed-Loop Extended Orthogonal STBC: Improved performance in imperfect synchronization

Substantial performance gain and a full coding rate can be achieved by utilizing a Closed-Loop Extended-Orthogonal Space-Time Block Coding (CL-EO-STBC) scheme in wireless relaying networks, referred to as D-CL-EO-STBC. So far, most research has focused on the perfect synchronization case and for only two-nodes wireless relaying networks. Unfortunately, perfect synchronization is difficult (or impossible) to achieve in wireless relaying networks, as a timing misalignment between the received versions of the transmitted signals from the relaying nodes will occur. In this paper, an improved detection scheme, based on a PIC detector which was previously introduced, is proposed to mitigate the performance degradation due to imperfect synchronization in four-nodes wireless relaying networks employing CL-EO-STBC. Numerical simulations show that the proposed detection scheme can achieve performance close to that of perfect synchronization even under severe imperfect synchronization conditions in just two iterations while maintaining a low-level of computational complexity.