Superposition Network Coding for Wireless Cooperative Communication

Spatial diversity can be exploited by the use of cooperative communication technology. However, most of the well known cooperative protocols have some practical challenges. In this paper we introduce two disadvantages of several important cooperative diversity protocols including low spectral efficiency and requirement for perfect time and frequency synchronization of relay nodes. Then, a cooperative strategy is proposed that improves overall 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 cooperative diversity in asymmetric wireless networks; hence the name superposition network coded cooperation (SNCC). The SNCC scheme is applied to a special but generalizable case of three users. In this case the receiver structure and error performance analysis of SNCC are presented. The results demonstrate performance improvement of wireless communication.