Pejman Khadivi - Department of ECE Isfahan University of Technology Isfahan, Iran
Shadrokh Samavi - Department of ECE Isfahan University of Technology Isfahan, Iran
Hossein Saidi - Department of ECE Isfahan University of Technology Isfahan, Iran
Terence D. Todd - Department of ECE McMaster University Hamilton, Canada

Blocking and dropping probabilities are two important performance parameters in cellular systems. In near future multi-mode mobile handsets will be popular all over the world. These handsets contain WLAN and cellular air interfaces, specifically designed for hybrid networking. When a multi-mode handset is within a WLAN, it is served by WLAN’s resources. When this handset moves outside the WLAN’s coverage area, it must be served by the cellular system. Therefore, vertical handoffs are necessary between different wireless networks. Traditional methods for dropping rate reduction can not be employed easily in loosely coupled WLAN/Cellular systems. This is because the system administrator of WLAN is different from the cellular one. In this paper, we propose a method for dropping rate reduction by using ad hoc relaying. We show that the ad hoc relaying can dramatically reduce dropping probability. Two-hop and multi-hop relaying methods with a number of routing strategies are suggested and compared through simulations.

Hybrid Wireless Networks, Ad hoc Relaying, Handoff, Dropping Probability