Relay assignment in multiuser cooperative radio networks with QoS guarantee

Adaptive cooperation with conflict-free relay assignment in a network setting is a challenging problem. The problem becomes even more difficult when users have quality-of-service (QoS) requirements but the available spectrum resource is limited, where admission control may be required. In this paper, we jointly study relay assignment and admission control in cooperative radio networks (CRNs). A one-stage optimization problem is formulated to integrate our multiple objectives. Since the problem in question is prohibitively difficult, we resort to an appropriate decomposition approach after a careful analysis on the structure of the formulated problem. A simple distributed algorithm is also proposed to overcome the inherent drawbacks of the centralized scheme. Numerical results demonstrate the benefits attained by jointly considering relay assignment and admission control, as well as the effectiveness of our proposed algorithms.