Asynchronous Power Control Game with Channel Outage Constraints in Cognitive Radio Networks

This study provides a general framework for distributed multi-user power control problems in cognitive radio (CR) networks over fading channels. Using a non-cooperative game with coupled constraints in CR and primary channel outages, the fundamental performance traits of power control for multiple CR users are analyzed in the present of multiple primary users (PUs) in fading environments for the first time. While the feasibility of target SINRs are always guaranteed in most studies for no-fading environments, the adopted channel outage model incorporates the probability that the SINR falls below a target threshold due to fast fading or interferences from other CR users. For the tractable analysis of the formulated problem, geometric programming approach is used to transfer it as a convex one. A dual decomposition approach is applied with layered structure for the constrained game, where each subproblem is full of economic interpretation. The properties of Nash Equilibrium (N.E.) for the proposed game are thoroughly investigated. An asynchronous distributed power control algorithm converging to the N.E. is designed, which ensures the robust implementation in fading environments. Finally, the simulation results and analysis are shown to enforce the effectiveness of the proposed algorithms for CR users over fading channels.