Joint Overlay-Underlay Optimal Power Allocation in Cognitive Radio

摘要

In this paper a novel cognitive radio system model is proposed in which secondary user transmitter (SU-Tx) operates under two modes underlay and overlay, based on the channel sensing information it receives. This is an effort to maximize transmission data rate based on the threshold which decides the mode of operation. In this paper, the resources are utilized efficiently by making them operate in both the modes. It provides the optimal power allocation to the CR user in a way that it should not provide interference to its neighbouring users, specifically the most prioritized primary/licensed users. The performance of each mode is analyzed with attainable ergodic and outage capacity.