Mobile Networks and Applications

, Volume 11, Issue 4, pp 625–640

Signal threshold adaptation for vertical handoff in heterogeneous wireless networks


  • Ahmed H. Zahran
    • Department of Electrical and Computer EngineeringUniversity of Toronto
  • Ben Liang
    • Department of Electrical and Computer EngineeringUniversity of Toronto
  • Aladdin Saleh
    • Bell Canada/Wireless Technology

DOI: 10.1007/s11036-006-7326-7

Cite this article as:
Zahran, A.H., Liang, B. & Saleh, A. Mobile Netw Appl (2006) 11: 625. doi:10.1007/s11036-006-7326-7


The convergence of heterogeneous wireless access technologies has been envisioned to characterize the next generation wireless networks. In such converged systems, the seamless and efficient handoff between different access technologies (vertical handoff) is essential and remains a challenging problem. The heterogeneous co-existence of access technologies with largely different characteristics results in handoff asymmetry that differs from the traditional intra-network handoff (horizontal handoff) problem. In the case where one network is preferred, the vertical handoff decision should be carefully executed, based on the wireless channel state, network layer characteristics, as well as application requirements. In this paper, we study the performance of vertical handoff using the integration of 3G cellular and wireless local area networks as an example. In particular, we investigate the effect of an application-based signal strength threshold on an adaptive preferred-network lifetime-based handoff strategy, in terms of the signalling load, available bandwidth, and packet delay for an inter-network roaming mobile. We present an analytical framework to evaluate the converged system performance, which is validated by computer simulation. We show how the proposed analytical model can be used to provide design guidelines for the optimization of vertical handoff in the next generation integrated wireless networks.


Heterogeneous wireless networksSeamless integrationVertical handoffApplication signal strength threshold3G cellularWireless LAN

Copyright information

© Springer Science + Business Media, LLC 2006