Vertical Handoff Algorithms for Heterogeneous 3G Networks

One of main challenges of fourth generation wireless networks (4G) will be the integration of various mobile technologies such as CDMA 1xEV-DO RA, UMTS/HSDPA and WiMAX. In this paper, the interoperability between the CDMA 1xEV-DO RA and the UMTS/HSDPA in the 4G context is investigated. New algorithms for vertical handoff traffic acceptance are proposed considering the link occupation, the buffer occupation, the radio signal strength (RSS) or the quantum size (DRR) of each 3G system, taken individually or in combination of them, as inputs for decision of vertical handoff process. Different algorithms are evaluated through QoS metrics such as the average packet delay and the loss percentage in function of vertical handoff traffic load. The results showed that depending on the chosen algorithm it is possible to assure the QoS of 1xEV-DO RA and UMTS/HSDPA systems and still to accept a good amount of vertical handoff traffic.