The optimal power allocation policies with perfect channel side information and buffer state information

In the multi-user wireless communication systems, the dynamic allocation of transmit power is an important means to deal with the time-varying nature at the physical layer and at network layer. Optimal power allocation with perfect channel and buffer state information is studied in this paper. We first build up the cross-layer model by integrating that of physical layer and network layer, and then formulate the optimization problem on power and rate allocations. We prove that the optimal solution to the power allocation problem can be regarded as an extension of the traditional water-filling technique. The corresponding dynamic programming algorithm is presented. Finally, rate allocation problem is solved as an inverse problem to the power allocation.