Novel Design of Sensing and Transmission Duration in Cognitive Radios for Energy Efficiency

This paper proposes a novel method for improving the energy efficiency in Cognitive Radio based wireless networks through optimisation of sensing duration and transmission duration. We analyse three different cases of allocating sensing time and transmission duration with in a Cognitive frame. The first case corresponds to optimising with respect to sensing duration alone, while keeping the transmission duration as decided by the frame duration or as decided by the transmit power constraints. Second case deals with optimization with respect to the transmit duration while the sensing duration is constant and the third case corresponds to optimising jointly with respect to both. Here, we consider the ratio of the sensing duration to the transmission duration. The problems are formulated as quasi-concave fractional programming problem. Results indicate that the third method is better compared to existing methods. Further, the computational complexity of this method is less compared to many existing methods.