Selection relaying in coded cooperation with delayed CSI over Rayleigh fading channels

Cooperation with channel coding also known as coded cooperation has been shown to be an efficient scheme for providing significant performance gains. However, relay selection in coded cooperation systems is seldom available in the existing literature. It is widely known that relay selection schemes in cooperative communications are dependent on the quality of the channel state information (CSI). In this paper, we study the impact of using outdated channel state information (CSI) for opportunistic relay selection (ORS) in turbo-coded cooperation over Rayleigh fading channels. A closed-form expression for the exact outage probability as a function of the correlation between the actual and delayed or outdated CSI is derived. Furthermore, diversity analysis is presented and it is noted that the diversity order is reduced to two regardless of the number of available relays, when the correlation factor is not equal to unity.