Distributed MAC Based on Adaptive Sensing Period Adjustment in Overlay Cognitive Radio Networks
Su Min Kim, Junsu Kim · 2013
In this paper, we propose distributed MAC protocols based on adaptive sensing period adjustment in overlay cognitive radio (CR) networks. The proposed MAC protocols adjust the sensing period based on both primary sensing and secondary data channel information at each CR user. A user with the shortest adjusted sensing period accesses to the channel in a distributed manner through an exchange of RTS/CTS messages. We propose two kinds of sensing period adjustment (SPA) protocols: logarithmic SPA (LSPA) and exponential SPA (ESPA) protocols. Through Monte-Carlo simulations, we evaluate the performance of the proposed protocols in terms of spectral efficiency and collision probability. Numerical results show that the collision probability is the most dominant factor to determine the spectral efficiency. The proposed ESPA protocol efficiently reduces the collision probability with a moderate increase of the sensing period.