Spectrum Handoff Scheme Based on Recommended Channel Sensing Sequence

We consider the spectrum handoff delay of a Secondary User (SU) in cognitive radio networks. We propose a spectrum handoff scheme based on Recommended Channel Sensing Sequence (RCSS), which aims to optimise the spectrum handoff delay subject to the sensing reliability and link maintenance constraints. There are two cases that should be considered: 1) the SU performs spectrum handoff successfully during the current frame, and 2) the SU successfully performs the spectrum handoff using several frames. We develop a dynamic programming algorithm for RCSS to identify the optimal sensing sequence for the first case, and an updating algorithm for RCSS to improve the handoff performance for the second case. The numerical results confirm that the proposed RCSS handoff scheme can achieve better handoff delay performance than others when the received signal-to-noise ratios of the Pus' signals on different channels are non-identical.