Degrees-of-freedom and interference tradeoff for a mix-Gaussian cognitive radio channel

We explore the degrees-of-freedom and interference tradeoff for a simple cognitive radio system under an assumption that the secondary-user (SU) receiver operates incoherently with the primary-user (PU) transmitter. This assumption makes our system model practically more rigorous, as compared to the conventional studies where a coherent operation is assumed. Due to the incoherent operation of SU receiver, the resulting interference channel is mixture-Gaussian. Our objective is to find the optimal sensing threshold and sensing time, for the signal detector that is used by the SU, such that the SU performance is maximized while the PU performance degradation, caused by the interference due to SU, remains within a tolerable range. Also, we define the interference regimes for SU performances on the basis of PU transmission power level.