Power allocation schemes for OFDM-based Cognitive Radio networks

This paper deals with spectrum sharing scenario, wherein cognitive radio users (secondary) and primary users coexist in adjacent frequency bands. It is imperative that in such scenarios, the interference introduced by the cognitive radio users in primary user band must be below the prescribed limits. We have proposed sub-optimal schemes for power allocation to cognitive radio users that can achieve performance comparable to the optimal schemes but with lesser complexity. The optimal scheme is compared with three proposed sub-optimal power allocation schemes. Numerical results arrived at also prove that the proposed sub-optimal schemes can achieve performance equivalent to the optimal scheme and the interference introduced by the cognitive radio users is within valid threshold limits.