Mobility management and multihoming in heterogeneous networks

Abstract

Heterogeneous networks become popular nowadays with wireless technologies such as WiMax, 3G/UMTS, WiFi, in which all could be deployed in a single device. The combination of multiple interfaces enables mobile devices to use either one or all of the interfaces at the same time. However, the support for mobility raises new issues not only in handoff management but also in the quality of service (QoS). Various research works have focused on how to manage QoS requirements in heterogeneous networks where delay sensitive real-time applications need low delay-tolerance and high bandwidth links. A novel framework to support mobility in heterogeneous network for multihomed devices with QoS support is proposed. Based on a cross-layer handoff approach, we make use of SIP protocol to ensure seamless connection during handover across networks. The solution employs multiple interfaces to take advantage of the multihoming capability of the device thus enhances QoS support for data transfer, especially in multimedia streaming. Unlike many current proposals, the framework can support both UDP and TCP transmissions where UDP is less reliable while TCP incurs extra delay and overhead. The framework has been implemented in a testbed. Experimental results collected from real-time streaming show that the framework can provide seamless mobility support and optimized flow distribution for heterogeneous multihomed mobile nodes. The seamless mobility idea is further extended. An application framework to support seamless handoff between 3G/UMTS and WLAN for VoIP applications on the Symbian iii ATTENTION: The Singapore Copyright Act applies to the use of this document. Nanyang Technological University Library platform is proposed. VoIP applications require high quality and low latency transmissions. Unlike other approaches, the proposed framework lies in the application layer of the mobile devices and hence does not require a change in network infrastructure. Neither is modification required in the kernel layer. Hence it is portable among mobile devices and is easily customized for different VoIP systems. We further apply the multihoming concept to Delay Tolerant Networks (DTN) and modify the DTN routing protocol MaxProp to exploit multiple network interfaces. Simulation results show that the multihomed MaxProp improves delivery rate and reduces message latency compared to the original MaxProp. The improvement is even more prominent when buffer space is limited in the DTN node. The DTN simulator, ONE (Opportunistic Network Environment) has also been modified to support the simulation of DTN with multiple interfaces.