Game theory based distributed approach for power and rate allocation to secondary users in cognitive radio networks

We consider a multi-channel cognitive radio network (CRN) where multiple secondary users share a single channel and multiple channels are simultaneously used by a single secondary user (SU) to satisfy its rate requirement. For such an environment, we develop a user-based distributed approach based on a game theoretic formulation. The overall objective is to determine the optimal power and rate (modulation order) distribution choices that each secondary user has to make in order to maintain their quality of service (QoS). Our measure for QoS include bit error rate (BER) and minimum rate requirement. First, we present the resource allocation problem assuming a centralized architecture. Next, we formulate a game considering distributed approach and show that the game has at least one Nash Equilibrium (NE). We present an algorithm to reach NE. Simulation results demonstrate that optimal transmit power follows “reverse water filling” process and rate allocation is proportional to signal to interference plus noise ratio (SINR). We illustrate that the solution from the distributed formulation conforms the centralized solution.