Power allocation for OFDM-based cognitive radio systems under average interference constraint

Power loading algorithms discussed in literature assume a static spectrum scenario where number of primary users remains constant in transmission period of cognitive user. In practice, new primary users can arrive or active primary users can depart at any time. In this paper we propose a new centralized power allocation technique taking into consideration arrival and departure of primary users that maximizes total capacity of cognitive user while honoring an average interference constraint. We also present numerical results to show that for known arrival and departure probabilities, the proposed method provides better primary protection than other static scenario based methods.