Joint optimal sensing threshold and subcarrier power allocation in wideband cognitive radio for minimising interference to primary user

Cognitive Radio (CR) can use the frequency band allocated to a Primary User (PU) on the premise that it will prevent significant of avoiding causing great interference to the PU. In this paper, we consider a wideband CR system where the Secondary User (SU) minimises its interference to the PU by jointly allocating the optimal sensing threshold and subcarrier power. A multi-parameter optimization problem is formulated to obtain the joint optimal allocation by alternating direction optimization, which minimises the total interference to the PU over all of the subcarriers subject to the constraints on the throughput, Bit Error Rate (BER) and maximal total power of the SU, the subcarrier rate and interference power of the PU, and the false alarm and mis-detection probabilities of each subcarrier. The simulation results show that the proposed joint allocation algorithm can achieve the desired mitigation on the interference to the PU at the different subcarrier gains.