Spectrum sharing based on spectrum heterogeneity and multi-hop handoff in centralized cognitive radio networks

Most previous work on spectrum sharing in the cognitive radio (CR) networks did not take into account the influence of node mobility on link available time as well as the spectrum heterogeneity. In this paper, a spectrum sharing algorithm based on spectrum heterogeneity is presented for centralized CR network, meanwhile the individual CR users are free to be mobile. A prediction model of channel usage time is proposed, which is based on the mobility of CR users and spectrum transmission range. The channel predicted usage time is main metrics for the spectrum sharing. In order to decrease channel handoffs resulting from short channel usage time, a usage threshold time is set for the channel allocation. When channel handoff cannot be implemented in a single hop, the multi-hop routing will be established to keep the communication. Simulation results reveal that the amount of channel handoffs can be considerably reduced after using the predicted channel usage time, the channel utilization is enhanced and the handoff blocking probability is also dramatically decreased simultaneously. In addition, the further simulation results show that apart from the PU activity, CR node´s mobility is also vital to the channel handoffs and link available time.