Optimum power allocation by using sub-gradient algorithm in Orthogonal Frequency Division Multiple Access Systems

Muti-user resource allocation for cooperative OFDM systems is proposed for use in multi-user situations. The objective is to minimize the total two-stage transmission power for each user for a given transmission rate, formulate the optimization problem and proposes several algorithms for the allocation of various resources. The main aim is to allocate sub-channels for minimizing the total power of transmission.