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One among the critical design issues in the case of heterogeneous wireless networks is regarding the vertical handoff support. Vertical handoff happens when a mobile terminal makes a switch from one network to another (e.g., from WLAN to CDMA 1xRTT). The aim of this work is about determining the circumstances during which the vertical handoff has to be performed. Typically, a mobile user can roam and achieve the vertical handover making use of single criteria, like the Received Signal Strength (RSS). However the decision of single criteria vertical handover, might lead to a handoff that is inefficient, imbalanced network load, and service disruption. For the purpose of improving the accuracy pertaining the vertical handoff decision for use in radio heterogeneous network, this paper presents a Hybrid Particle swarm optimization based Multi criteria Vertical Handoff (HPMVHO) decision algorithm employing multi criteria metrics in the heterogeneous network environment that consists of three network interfaces: (i) Wireless Local Area Network (WLAN), (ii) Wideband Code Division Multiple Access (WCDMA), and (iii) Worldwide Interoperability For Microwave Access (WiMAX). In vertical handover decision, the metrics including Received Signal Strength (RSS), Network Throughput, bandwidth available, Power consumption, Expenditure, Security and user choices are taken into consideration. In the HPMVHO decision algorithm proposed, Fuzzy logic is applied for representing the inaccurate information of some of the attributes and user preferences. The Fuzzy logic considers the crucial criteria of the vertical handoff in the form of the input variables and then the handoff decision is made on the basis of the weight values defined. The weight values to every service has to be assigned in accordance with the quality with respect to the services parameters to each of the sensor on the basis of the Hybrid Particle Swarm Optimization (HPSO). The Extreme Learning Machine (ELM) assists in making the prediction for the number-of-users belonging to the after-handoff network that plays the role of a pivotal variable of the HPSO. This algorithm renders precise decision by using reasonable inference for designing the crucial multi criteria and then deciding over efficient decision technique. Finally, examples illustrating the proposed techniques are given, and the sensitivity of the strategies are examined. |
