Power allocation in multi-node cooperative network in Rician fading channels

Cooperative communications have been recommended to exploit the inherent spatial diversity gains in multiuser wireless systems without the need of multiple transceivers at each node. This is achieved when wireless nodes help to each other to send multiple independent transmission paths to the destination. The advantage of cooperation can be exploited significantly by allocating the power of the system optimally. Thus, in this paper we first derive the approximate symbol error rate (SER) for multi-node cooperative networks employing decode-and-forward (DF) protocol with a maximum ratio combining (MRC) at the receiving terminals in Racian fading channels. Using the approximated SER expression, optimal power allocation (OPA) scheme under different line-of-sight (LOS) scenarios is investigated. Numerical and simulation results are presented to illustrate the performance improvement due to OPA of the cooperative networks.