Vertical Handoff Decision Algorithm Based on Predictive RSS and Reduced Fuzzy System Using Rough Set Theory

摘要

This paper proposes a novel vertical handoff decision algorithm in heterogeneous environment based on predictive RSS and reduced fuzzy system using rough set theory. To reduce Ping-Pong effect as well as call dropping probability, a predictive RSS with dwell time scenario is proposed in this paper. Many factors such as received signal strength, coverage area, cost of networks, security as well as network delay should be considered in vertical handoff decision. As fuzzy logic has the advantage of dealing with imprecise data and incorporating with human expertise, fuzzy system with multi-inputs should be applied in vertical handoff decision. However, the computational complexity of fuzzy system follows an exponential increase with the number of input parameters which limits its practicability. Consequently, an attributes reduction method based on rough set theory is further studied in this paper. Simulation results show that this fuzzy-based algorithm is able to reduce lots of Ping-Pong effect, besides, the reduced rules base using rough set theory has similar performance compared with complete rules base which makes fuzzy-based algorithm more practical in vertical handoff decision.