EFFICIENT WEIGHTED-SUM-RATE MAXIMIZATION FOR A CLASS OF HALF-DUPLEX COOPERATIVE SYSTEMS

In many half-duplex cooperative systems, the direct formulation of the problem of finding the jointly optimal power and channel resource allocation that maximizes a weighted sum of the achievable rates can be difficult to solve. In this paper, we provide an efficient algorithm to solve this problem for a class of systems with convex achievable rate regions. For those systems, we show that the weighted-sum-rate problem can be solved using a bisection-based search in which a “target rate” problem is solved at each step. The target rate problem involves maximizing one of the achievable rates subject to target values for the other rates, and can be efficiently solved in a number of cases. We show that the proposed technique can be applied to orthogonal multiple access relay systems and that joint optimization can result in significantly larger weighted sum rates than optimization over the powers alone with a fixed channel resource allocation.