Efficient Vertical Handover Decision Algorithm using Multi- criteria Metrics

Abstract

The ever-increasing data and services demand of the users has been catered well by the remarkable development of the heterogeneous network. A ubiquitous seamless connection between architecturally different networks requires an efficient vertical handoff mechanism. Considering only the received signal strength (RSS) to decide when and where handover initiates is an inefficient approach to determine the target network. Multiple criteria have to be taken into account as not all the available networks have similar capacity, availability and services as that of users’ requirement. In an integrated network environment consisting of WiMAX, WCDMA and WLAN, RSS method of handover is performed and multicriteria Technique for Order Preferences by Similarity to an Ideal Solution (TOPSIS) method of handover decision algorithm is analyzed. A multicriteria fuzzy rule based handover decision algorithm is developed where the number of rules for four inputs and three memberships function is reduced by using Iterative Dichotomizer 3 (ID3) method. The number of handoffs seen in fuzzy rule base algorithm is higher than in RSS and TOPSIS method but fuzzy method showed a better load balancing property in the analysis. The load balance index of fuzzy method is 25% better than RSS method and 41% better than TOPSIS method using random waypoint mobility. Using Manhattan mobility, the load balancing property of fuzzy method is 21% better than RSS method and 17% better than TOPSIS method. The percentage of blocked requests with respect to successful handoff request varies between 2.07 - 4.8%.