Adaptive power allocation for secondary users in Cognitive Radio networks

In a Cognitive Radio spectrum sharing scenario, the side-lobe interference from an OFDM-based secondary user (SU) causes unwanted interference to the primary user (PU) of the spectrum. The objective of this work is to allocate power in the SU sub-carriers such that it maximizes its throughput, within a power budget, while ensuring that the interference to the PU is within a specified threshold. We assume a more realistic and effective solution by mitigating the interference to each of the sub-bands of the PU. Assuming knowledge of the instantaneous channel gains on the SU to SU link, as well as those of the SU to PU link, an iterative algorithm is proposed to achieve the aforementioned objective. Simulation results are provided, which indicate that the proposed algorithm outperforms those which have been previously presented in literature.