Distributed Space-Time Block Coding for Two-Way Wireless Relaying Networks: Improved Performance under Imperfect Synchronization

Two-way Wireless Relaying Networks (TWRNs) have attracted interest recently due to the substantial bandwidth efficiency and performance they can achieve. So far, most research has assumed perfect timing synchronization within the network. Unfortunately, perfect synchronization is difficult (or impossible) to achieve as a timing misalignment between the received versions of the two-way transmitted signals will occur at both transmission phases. In this paper, an enhanced Parallel Interference Cancellation (PIC) detector for TWRNs employing a Space-time block code is proposed to mitigate efficiently the performance degradation caused by imperfect synchronization. In addition, a change in the transmission scheme of the TWRN is also introduced that will enable a symbol-wise decoding process at the receiving node. Unlike the previous PIC detector, 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.