| Popis: |
Cognitive radio technology allows the secondary users to utilize the spectrum, when it is not occupied by the primary users. Whenever a primary user wants to utilize a channel which is occupied by a secondary user, the secondary user should perform a proactive spectrum handoff to another channel and vacate the selected channel before the primary user utilizes it. This scheme avoids collision between the primary users and secondary users; moreover, increases the throughput of the primary and secondary users. In this paper, a novel proactive spectrum hand protocol based on the Greedy Channel Selection (GCS) is proposed which avoids collision between secondary users, as well as, collision between primary and secondary users. In the proposed scheme, proactive spectrum handoff is based on the SRV (Single Rendezvous) coordination scheme; therefore, the secondary users perform proactive spectrum handoff without using the common control channel. Moreover, the channel selection is distributed which leads to the higher throughput, and lower average service time. The proposed proactive spectrum handoff protocol is compared with the other proactive spectrum handoff protocols. Simulation results illustrate that the proposed protocol outperforms the other protocols regarding higher average throughput and lower average service time. |
