Fuzzy logic based spectrum handoff decision for prioritized secondary users in cognitive radio networks

Recent studies have revealed that due to the increasing number of wireless users, spectrum scarcity problem has arisen. In order to alleviate this problem, cognitive radio technology has emerged with the aim of using available spectrum in an opportunistic manner by secondary users. While utilizing licensed spectrum, it is inevitable for secondary users not to cause any interference to the primary users. Once the primary user activity is detected on the licensed channel at the time of on-going transmission of secondary user, secondary user must either change the licensed spectrum or stop its transmission. This case of changing spectrum by secondary user is known as spectrum handoff. In this paper, fuzzy logic based spectrum handoff decision is carried out by using data rate, channel usage, and priority. Different data traffics such as audio, and video are considered for secondary users. In order to simulate data traffics, two different simulation scenarios are realized. Besides, several priority classes are taken into account for urgent and real-time communications. In the proposed system, it is seen that accurate spectrum handoff decisions are made for different traffic types.