Superposition network coding for wireless cooperative communication

Cooperative diversity is an innovative approach to improve the reliability of communication. However, this technology is challenging in practice. Time and frequency synchronization of relay nodes in simultaneous based cooperative diversity protocols are very important. Hence, realization of such requirement is difficult. Although separation in transmission time of terminals in traditional time division multiple access (TDMA) method can solve the synchronization problems, but it leads to lower spectral efficiency. In this paper a cooperative strategy is proposed for asymmetric wireless networks that improves overall wireless communication performance in comparison with non-cooperative protocols with high spectral efficiency and non synchronization problems. In this technique, we use a combination of superposition coding and network coding to achieve incremental diversity in asymmetric wireless networks; hence the name superposition network coded cooperation (SNCC). The receiver structure is presented as simple as possible. The error performance of SNCC is analyzed by appropriate approximations and the analytical results are compared with simulation results. The results demonstrate improvement in error performance and the network lifetime.