We investigate into the potentiality of an enhanced Power and Location-based Vertical Handover (PLB-VHO) approach, based on a combination of physical parameters (i.e., location and power attenuation information), for mobile-controlled connectivity across UMTS and WLAN networks. We show that the location information in a multiparameter vertical handover can significantly enhance communication performance. In the presented approach a power attenuation map for the visited area is built and kept updated by exploiting the information sharing of power measurements with other cooperating mobile devices inside the visited networks. Such information is then used for connectivity switching in handover decisions. The analytical model for the proposed technique is first presented and then compared with a traditional Power-Based approach and a simplified Location-Based technique. Simulation results show the effectiveness of PLB-VHO approach, in terms of (i) network performance optimization and (ii) limitation of unnecessary handovers (i.e., mitigation of ping-pong effect). 1. Introduction Current heterogeneous wireless networking scenarios include multimode Mobile Terminals (MTs) equipped with multiple wireless Network Interface Cards (NICs) and providing Vertical Handover (VHO) capability to autonomously select the best access. VHO allows switching from one access technology to another thus offering additional functionalities with respect to horizontal handover, where MTs move from an Access Point (AP) to another without changing the serving access network [1, 2]. A VHO process aims to guarantee seamless connectivity between heterogeneous wireless networks inside areas where simultaneous coverage from multiple networks is provided [3, 4]. Selection of the serving network can be based on optimality criteria which balance different factors including, for instance, monetary cost, energy consumption and end-user Quality-of-Service (QoS) [5]. In order to obtain an optimal tradeoff among these factors, while assuring high service continuity, fast and reliable procedures for the selection of the serving network have to be designed in the case of link degradation or loss of connectivity. Various wireless networks exhibit quite different data rates, link errors, transmission range and transport delay. As a consequence, a direct comparison between heterogeneous wireless links in order to select the best network to attach to is not always straightforward. In general, a VHO strategy requires a preliminary definition of performance metrics for all the networks providing access
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