Local rerouting and channel recovery for robust multi-hop cognitive radio networks

Due to the dynamic interruptions from the primary users (PUs), the secondary user (SU) (i.e., cognitive radio) network is highly dynamic with fast varying radio resources. Once a PU requests to occupy the licensed spectrum, all of affected SUs (i.e., those SUs who opportunistically access the licensed spectrum) are mandated to immediately terminate the spectrum usage and switch their data transmissions to other unoccupied spectra to avoid interference with PUs. During the spectrum transition phase, the severe throughput degradation may occur in SU networks. In this paper, we proposed a local rerouting and channel recovery (LRCR) scheme to dynamically search the rerouting paths and available channels for those affected SUs. When a channel is occupied due to the request of a PU, the SUs who use the same spectrum as the PU instantly perform the proposed LRCR scheme to find an unoccupied path for data rerouting. The proposed LRCR scheme can be combined with the existing robust topology control approach. Simulation results demonstrate that the proposed scheme can be effectively applied to the existing robust topology control approach and efficiently enhance robustness and network throughput.