Effects of opportunistic relay selection on the performance of distributed Turbo coded cooperative systems

In this work, the error performance of the distributed Turbo coded cooperative systems in a multi-relay environment is investigated based on the number of relays and relay selection. First, one of two selected relays having best paths among M relays uses Amplify and Forward (AF) protocol, and the other one uses Decode and Forward (DF) protocol. Then, the component codes of the distributed parallel concatenated (Turbo) code are sent to receiver by these two relays. This type of a system is called Distributed Turbo Coded Cooperative Systems (DTCS). In addition, this system is compared with another system having a similar structure but only uses convolutional codes. Numerical results show that the DTSC outperforms the system including only convolutional code, with the increment of the total number of relays. On the other hand, the use of DF protocol rather than AF for the better relay among the two best relays gives a better performance in the DTSC system.