A New Multi-Attribute Base-Station Association Technique for Hybrid Wireless Networks

摘要

Handoff is the process of maintaining a user's active session(s) when an MS changes its Point of Attachment (PoA) to a different wireless Network Access Technology (NAT). A horizontal handoff occurs between PoAs supporting the same wireless NAT, while for Vertical Handoffs (VHOs), the PoAs involve different NATs. A handoff decision includes the selection of a new PoA among all other available candidates based on certain criteria. Thus, efficient handoff schemes need to be designed to select a target network that can fulfill the QoS requirements for a wide variety of applications while allowing seamless mobility among a multitude of NATs. This paper presents a multi-criteria VHO algorithm for heterogeneous wireless networks, which achieves seamless mobility while maximizing end-users' satisfaction. Two important modules are designed; the first module estimates the necessity of VHOs and the other module is developed to select the best network as the target of VHO. The target network selection algorithm is developed utilizing a weighting scheme that is based on the Analytic Hierarchy Process (AHP) and differentiates between different classes of traffic. Simulation results are provided and compared for four different traffic classes.