Power allocation for single secondary user in OFDM-based cognitive networks with comprehensive interference considerations

Conflict-free power allocation for secondary user (SU) in cognitive networks is a challenging problem since the accessible spectrum of the SU is shared with the primary user (PU); the problem becomes to be especially difficult when it is wanted to achieve the maximum network capacity considering the mutual interference between PU and SU. In this paper, specifying the single SU case with multiple PUs, the power allocation for the subcarriers of the SU is modeled into a single user water-filling framework, where the mutual interference between the PUs and the SU is comprehensively formulated into the restrictions on the SU´s transmission power. As a result, proposed modeling scheme restrains the interference to the PUs as well as maximizes the capacity of the SU. Simulation results illustrate the influence of the mutual interference on the power allocation and the network capacity.