Optimal Sensing and Power Allocation in Pilot-Aided Shared Access Systems: A BER Minimization Approach

Abstract

We investigate the performance of a hybrid, opportunistic/underlay Licensed Shared Access (LSA) system, in the presence of Spectrum Sensing (SS) and Channel Estimation (CE) uncertainties, and derive a simple closed form expression for the system's Bit Error Rate (BER). Based on the derived expression, we introduce an optimization problem for optimally selecting the time allocated to the SS and CE tasks, as well as the transmit power allocation, such as to minimize the BER of the LSA licensee system, given an average transmit power constraint. It is interestingly observed that the optimal SS time is a decreasing function of the duty cycle of incumbent communication and increases as the system becomes more interference-prone.