Efficient Vertical Handoff Algorithm for improved QoS in Heterogeneous Networks

Abstract

Fourth Generation computing environment is a revolution not only to move beyond the limitations and problems of 3G but also to enhance seamless mobility and promote ubiquitous computing. Growing consumer demand, to access always best connected communication services, is driving an accelerated technological development towards the integration of various wireline and wireless access technologies. The mobile user newlineexperience and Quality of Service (QoS) is of prime importance across such diverse access networks. Thus, to ensure seamless mobility across disparate heterogeneous newlinenetworks, efficient handoff schemes need to be implemented which in turn enhance QoS and offer reliable ubiquitous computing environment. newline newlineThe present work focuses on improving the user experience and QoS across the overlay network of two different technologies, i.e. WLAN and cellular network. A novel approach to vertical handoff has been proposed in this thesis based on multiple parameters. The enhanced Vertical Handoff Decision Algorithm (VHDA) proposed in this thesis considers six parameters like Received Signal Strength (RSS), velocity of mobile terminal, bandwidth available, number of users, coverage area, battery level and applies rule based neuro-fuzzy approach for handoff decision. The number of unnecessary vertical handoffs and correct vertical handoffs are measured in a simulated environment for the proposed algorithm and the results are compared with RSS based classical technique and fuzzy based approach. The simulation based performance evaluation demonstrates that the average number of vertical handoffs for the proposed vertical handoff algorithm is reduced by 13.3% than the existing fuzzy technique and 29.8% than the classical technique. Further, the reduction in the number of unnecessary vertical handoffs in the proposed algorithm is shown to reduce pingpong effect by 15.9%, improve the End-point Service Accessibility (ESA) by 16.57% and throughput by 5.97% with respect to existing fuzzy technique, leading towards improved QoS.