Impact of mobility on traffic distribution in seamless interworking environments

In future systems beyond IMT-2000, macrocell cellular systems such as the 3G systems and high bandwidth wireless systems such as wireless LAN will complement one another. Routing in the systems beyond IMT-2000 supports seamless inter- and intra-system handover among the cellular and WLAN systems by maintaining active connections. Consequently, the time scales of mobility and bandwidth-sharing behavior cannot he easily separated. It is not obvious what fraction of traffic is accommodated by each cellular and WLAN system, i.e. the traffic distribution is unknown. This paper shows the considerable impacts the mobility of users has on the capacities of the systems beyond IMT-2000 with roaming capability between different bit rate systems. Especially, this paper demonstrates that the traffic distribution among different systems is a major factor in defining total network throughput. We also provide an analytical method to determine the traffic distribution based on the theory of queueing networks.