Resource allocation for wireless relay channels

Resource allocation for a fading orthogonal relay channel model is investigated, where the source transmits to the relay and destination in one channel, and the relay transmits to the destination in an orthogonal channel. Separate power constraints at the source and relay are assumed. The fading state information is assumed to be known at both the transmitter and receiver. The source and relay can allocate their power adaptively according to the instantaneous channel state information. An achievable rate for this model is derived, and is optimized over the power allocation at the source and relay. This optimization is a max-min problem. A general technique for solving this max-min problem is introduced and applied to derive the optimal power allocation. The analysis is extended to the joint optimization of power and channel resource (time and bandwidth) allocations. In these scenarios, the maximum capacity of the channel (optimized over all possible power and channel resource allocations) is obtained for some special cases.