Multiband channel restoration scheme for opportunistic spectrum access in cognitive radio

Cognitive Radio (CR) is an approach for efficient spectrum utilization by the secondary user. But as the channel quality degrades due to environmental effects such as fading or the primary users´ reaccess of the channel, the secondary user has to vacate the channel. After that secondary user has to start restoration by searching and sensing other channels. Restoration is done with an objective of finding the best channel in shortest possible time to enhance the CR users´ throughput. In this paper, we propose a multiband restoration scheme so that the throughput of the CR is increased and the number of channels to be sensed get reduced to a great extent as compared to single channel restoration scheme and the Threshold First (TF) scheme as well. In this scheme, two or more channels are sensed at a time for the implementation of restoration scheme. Simulation results are showing the improvements in throughput as well as the reduction of the number of channels to be sensed with the multiband restoration scheme.