A novel spectrum sensing and access algorithm for considering competitive second users in cognitive wireless networks

In this paper, the problem of determining the maximum throughput and minimum delay for ensuring the Quality of Service(QoS) of second users(SUs)is investigated for the cognitive network. A markov chain modeling working status of SU has been established. We analyze the special case of the competitive SUs to sense and access the available spectrum channel. We assign the idle channel to the user who has the largest packet first and carry more competitive users as much as possible during a time slot. Our algorithm is called LFCM(Largest First and Carry more). In terms of handling the competitive SU, the existed literatures select one randomly to access the channel. We call this scheme to RANDOM. We derive the higher throughput and shorter average delay than RANDOM through the presented simulation result.