Interference model for spectrum sensing with power control

This paper analyzes the aggregate interference in a cognitive radio network. We consider a model in which the secondary transmitters are geographically distributed according to a Poisson point process in a wireless environment subject to shadowing noise and path loss. The secondary transmitters may transmit simultaneously and consequently incur an aggregate interference level on the primary system. We derive the moment generating function and the expectation of the aggregate interference for this model using properties of the Poisson point process. Based on the interference analysis, a scheme is proposed to estimate the maximum transmission power for each of the active secondary transmitters so as to satisfy a constraint on the aggregate interference. Our numerical results show a significant gain in the achievable capacity for the secondary system relative to an earlier scheme in which only a single secondary transmitter was permitted to transmit at any given time.