Abstract:  

The emerging IEEE 802.21 standard aims to create a framework to support protocols for enabling seamless handovers among various wired and wireless access technologies such as the third-generation (3G) wide area cellular telephony networks, IEEE 802.11 Wireless Local Area Networks (WLANs), IEEE 802.16 Worldwide Interoperability for Microwave Access (WiMAX), as well as wired links like IEEE 802.3.

 

The framework will also play an important role towards the creation of Fourth-Generation (4G) wireless systems. Handsets with multiple interfaces will be able to choose the most advantageous link among available alternatives. By having this, mobile users will be able to get higher data rates in cost effective ways. But, in order to enjoy these benefits, new algorithms are needed to make the 802.21 to work efficiently, otherwise the emergent architectural complexity will diminish or cancel the potential benefits. A critical part of this framework is the decision algorithms to minimize, or whenever possible to eliminate the unnecessary vertical handovers, as every handover activity consumes network resources and may degrade the quality of existing connections.

 

In this report, the author provides the outline of a handover architecture, summarizes the research work done as part of the proposed architecture, presents the results obtained so far, and plans for the future research activities. In the method developed, received signal strength (RSS) measurements are used to reduce the number of handovers. The traveling distance inside a WLAN cell is estimated through the successive RSS measurements, and compared against a distance threshold which is calculated from various network parameters. The results obtained show that significant number of handovers can be avoided when a mobile terminal (MT) travels through WLAN and cellular network cells.

About the Speaker: Iris is a postgraduate research student with the Department of Electrical and Computer Systems Engineering at Monash University