Impact of Transmit Power Control and Receiver Association on Interweave Network Interference

Erroneous beacon detection by interweave secondary nodes generates interference on the primary system. This paper analyzes how the aggregate interference behaves when secondary nodes use transmit power control and receiver association schemes. For this purpose, secondary transmitter nodes and receiver nodes are assumed to be distributed over a circular region and over the entire 2-D plane respectively. Two independent Poisson point processes model these distributions. We propose a receiver association scheme where each secondary transmitter attempts to connect to the closest available receiver. If it is not available, the transmitter attempts to connect with the next closest. This process continues until the M-th closest receivers are scanned. If no receiver is available, the transmitter remains silent. Moreover, a per-user transmit power control scheme is considered in which the transmit power is based on the distance between the transmitter and the associated receiver subject to a cut-off power level. All links are assumed to undergo path-loss and Rayleigh fading. The exact moment generating function (MGF) of the aggregate interference, the outage probability of the primary system, and the average probability of concurrent transmission are derived. Validated by simulations, our results show how the aggregate interference is affected by secondary power thresholds, receiver densities, and availability of the secondary receiver.