Secondary User Aggressiveness Optimization in Sensing-Transmission Scheduling for Cognitive Radio Networks

Abstract

The constraint of limited frequency spectrum for wireless communication is very daunting. The radio spectrum licensed to permanent users is wasted at times when not used continuously. Cognitive radio technology involves a change in regulation of radio spectrum. In cognitive radio networks a secondary user network is designed for efficiently using gaps in spectrum and not causing at the same time harmful interference to license holding primary users. There is a continuous tradeoff between the opposing goals of Primary User transmission protection and Secondary User throughput maximization. For a Secondary User, both sensing and transmitting is important so as to avoid collisions, packet loss and improve throughput. This paper presents optimization of Secondary User packet length in sensing-transmission scheduling for dynamically accessing the spectrum in cognitive radios. The need to maximize the Secondary User access is achieved by optimizing its packet length with respect to collision cost in a threshold based sensing-transmission structure using Matlab simulations. The results are presented in the form of traces of thresholds for different packet lengths and collision costs. This scheme optimizes Secondary User aggressiveness and throughput while safeguarding Primary User interests