Dynamic Coded Cooperation Using Multiple Turbo Codes in Wireless Relay Networks

In this paper, we propose a dynamic coded cooperation using multiple turbo codes in wireless relay networks where both relay and destination are equipped with a sensing device and the relay is assumed to determine autonomously if it should cooperate or not. We first elucidate the fact that the puncturing patterns of the multiple turbo codes determine the achievable diversity order by deriving their pairwise error probabilities (PEP). This is followed by a derivation of a simple power detector at the destination that can estimate a precise duration of cooperation phase upon decoding information. Furthermore, we investigate the impact of process delay due to cognitive processing at the relay, which results in the loss of diversity gain, and propose a simple null padding as its countermeasure. Computer simulations show that our proposed approach is able to achieve a full diversity and the frame error rate (FER) performance superior to that of conventional cooperative communications that make use of turbo coding structure even in practical scenarios.