Evaluation Model for Vertical Handoff Algorithms

Evaluation Model for Vertical Handoff Algorithms

Alexander Garcia D. (Alexander Garcia D.Universidad Autonoma de Occidente, Colombia), Lina Escobar P. (Lina Escobar P.Universidad Autonoma de Occidente, Colombia), Andres Navarro C. (Andres Navarro C.Universidad ICESI, Colombia), Fabio G. Guerrero (Universidad del Valle, Colombia) and Enrique Stevens-Navarro (Universidad Autonoma de San Luis Potosi, Mexico)
DOI: 10.4018/978-1-4666-0191-8.ch003


This chapter begins by introducing the problem of vertical handoff in heterogeneous wireless networks and illustrates the lack of a proper evaluation model to compare the different Vertical Handoff Algorithms (VHAs) that have been proposed in the literature over the last few years. In the following sections, a novel evaluation model for VHAs is introduced and described. The design of the new evaluation model is based on the multi-criteria evaluation methodology and criticality analysis, which permitted the model to be developed as a software component. The new proposed evaluation model is flexible in terms of the number of evaluation parameters and facilitates the analysis of VHAs by researchers. A specific case study considering some VHAs is presented, analyzed, and discussed in detail. The case study is used to compare the proposed evaluation model with another evaluation model (Ordinal Model) for VHAs. The comparison of the new evaluation model with an alternative evaluation model was an important exercise because it gave feedback on both models, enabling the authors to refine them and to propose extensions to their capabilities and features. The obtained results show that both models are valid and effective for the evaluation of the VHAs and each one has his advantages and disadvantages.
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Vertical Handoff

A vertical handoff is the process of changing the mobile connection between access points that support different wireless technologies (i.e. heterogeneous networks). Alternatively, in a horizontal handoff the connection just moves from one base station to another within the same access network. The vertical handoff process consists of three phases (Stevens-Navarro & Wong, 2006): network discovery, handoff decision and handoff execution. In the first phase, the Mobile Terminal (MT) discovers its available neighboring networks. In the decision phase, the MT determines whether it has to redirect its connection based on comparing the decision factors offered by the available networks and required by the mobile user, which is based on the information gathered in the first phase. The last phase is responsible for the establishment and release of the connections according to the vertical handoff decision.

The vertical handoff issue between heterogeneous networks has been much studied by a number of researchers and several solutions have been proposed (Garcia & Jimenez, 2008; Hong, Kang, & Kim, 2005; Kassar, Kervella, & Pujolle, 2008; Lee, et al., 2009; Nasser, et al., 2006; Yan, Sekercioglu, & Narayanan, 2010). However, there is still a lack of a proper evaluation model to compare the vast of VHAs in the literature.

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