On the target channel sequence selection for multiple handoffs in cognitive radio-based wireless regional area networks

In cognitive radio networks, handoff occurs when an unlicensed spectrum user has to switch to a new target channel from its current operating channel which a secondary user was using opportunistically. This situation raises whenever either the licensed primary user appears again or the channel's condition get worst. Substantial sensing time can be saved if a secondary user can make a proactive decision about selecting the future vacant target channel to resume the unfinished transmission before starting its transmission. This paper proposes a novel target channel sequence selection scheme for cognitive radio networks, which minimises the estimated service time of a secondary user by reducing the multiple handoffs. A non-iterative algorithm is implemented, which does not require the use of an exhaustive search technique as usual to determine the target channel sequence. Simulation results show that the proposed scheme outperforms both the random scheme and a considered benchmark scheme in terms of service time, cumulative handoff delay and throughput achieved by the secondary user.