Handoff Between a Wireless Local Area Network (WLAN) and a Wide Area Network (UMTS)

Abstract

WITH THE APPEARANCE OF WIRE LESS DATA NETWORKS WITH VARIABLE COVE RAGE, BAND WIDTH AND HANDOFF STRATEGIES, IN ADDITION TO THE GROWING NEED OF MOBILE NODES TO FREELY ROAM AMONG THESE NETWORKS, THE SUPPORT OF AN INTEROPERABLE HANDOFF STRATEGY FOR HYBRID WIRE LESS DATA NETWORKS IS A REQUIREMENT THAT NEEDS TO BE ADDRESSED. THE CURRENT TREND IN WIRE LESS DATA NETWORKS IS TO OFFER MULTI MEDIA ACCESS TO MOBILE USERS BY EMPLOYING THE WIRE LESS LOCAL AREA NETWORK (WLAN) STANDARD IEEE802.11 WHILE THE USER IS LOCATED INDOORS; ON THE OTHER HAND, 3RD GENERATION WIRELESS NETWORKS (WAN) ARE BEING DEPLOYED TO PROVIDE COVE RAGE WHILE THE USER IS LOCATED OUTDOORS. AS A RESULT, THE MOBILE NODE WILL REQUIRE A HANDOFF MECHANISM TO ALLOW THE USER TO ROAM BETWEEN WLAN AND WAN ENVIRONMENTS; UP TO THIS DATE SEVERAL STRATEGIES HAVE BEEN PROPOSED (SATTARI ET AL., 2004 AND HYOJIN, 2007) IN THE LITERATURE, HOWEVER, NONE OF THESE HAVE BEEN STANDARDIZED TO DATE. TO SUPPORT THIS INTEROPERABILITY, THE MOBILE NODE MUST BE EQUIPPED WITH CONFIGURABLE WIRE LESS INTER FACES TO SUPPORT THE HANDOFF BETWEEN THE WLAN AND THE WAN NETWORKS. IN THIS WORK A NEW ALGORITHM IS PROPOSED TO ALLOW A MOBILE NODE TO ROAM BETWEEN A WIRE LESS LOCAL AREA NETWORK (IEEE802.11) AND A WAN BASE STATION (UMTS), WHILE EMPLOYING IP MOBILITY SUPPORT. THE ALGORITHM IS IMPLEMENTED IN SIMULATION, USING THE NETWORK SIMULATOR 2.