Power and rate allocation to secondary users in competitive cognitive radio networks

In this paper, we study a resource allocation problem, specifically allocation of power and rate (modulation order) to secondary users in a competitive cognitive radio network (CRN). In a competitive CRN, multiple secondary users share a single channel and multiple channels are simultaneously used by a single secondary user (SU) to satisfy their rate requirements [1]. In such an environment, we compute optimal power and rate distribution choices that each secondary user needs to make in order to maintain their quality of service (QoS). Our measures for QoS include bit error rate (BER) and minimum rate requirement. We consider M-ary amplitude shift keying (M-ary ASK) modulation scheme and following the concept in [1], we work on transforming the BER constraint into a convex constraint in order to guarantee optimality of the resulting solutions. Simulation results demonstrate that optimal transmit power follows “reverse water filling” process and rate allocation follows signal to interference plus noise ratio (SINR).