  This paper presents a relay selection for decode-and-forward based on network
coding (DF-NC) and analog-NC protocols in general scheme of cellular network
system. In the propose scheme the two source node simultaneously transmit their
own information to all the relays as well as the destination node, and then, a
single relay i.e. best with a minimum symbol error rate (SER) will be selected
to forward the new version of the received signal. Simulation results show
that, the DF-NC scheme with considerable performance has exactness over
analog-NC scheme. To improve the system performance, optimal power allocation
between the two sources and the best relay is determined based on the
asymptotic SER. By increasing the number of relays node, the optimum power
allocation achieve better performance than asymptotic SER.
