关键词: 认知无线电，非连续正交频分复用，功率分配

Abstract: This paper investigated power allocation algorithms for NC-OFDM based cognitive radio system, which access the spectrum originally licensed to an OFDM primary system. According to transfer status of primary users, there will be different constraint strategies:A new criterion referred to power leakage interference factor is proposed to constraint leakage power to primary users in the cognitive users’working channels; meanwhile, on the primary users’working channels, primary users are protected by keeping the interference introduced to primary users' rate loss below a threshold. Power allocation algorithm maximizes the rate of the cognitive radio system based on the hybrid constraint strategics. hhen the numerical result show that, compared with the conventional interference power constraint, the cognitive system can achieve a significant rate gain under the proposed constraint.

Key words: Cognitive radio, NC-OFDM, Power allocation