An optimized QoS scheme for IMS-NEMO in heterogeneous networks

The network mobility (NEMO) is proposed to support the mobility management when users move as a whole. In IP Multimedia Subsystem (IMS), the individual Quality of Service (QoS) control for NEMO results in excessive signaling cost. On the other hand, current QoS schemes have two drawbacks: unawareness of the heterogeneous wireless environment and inefficient utilization of the reserved bandwidth. To solve these problems, we present a novel heterogeneous bandwidth sharing (HBS) scheme for QoS provision under IMS-based NEMO (IMS-NEMO). The HBS scheme selects the most suitable access network for each session and enables the new coming non-real-time sessions to share bandwidth with the Variable Bit Rate (VBR) coded media flows. The modeling and simulation results demonstrate that the HBS can satisfy users' QoS requirement and obtain a more efficient use of the scarce wireless bandwidth

Survivability, Scalability and Security of Mobility Protocols

Today mobile computing has become a necessity and we are witnessing explosive growth in the number of mobile devices accessing the Internet. To facilitate continuous Internet connectivity for nodes and networks in motion, mobility protocols are required and they exchange various signaling messages with the mobility infrastructure for protocol operation. Proliferation in mobile computing has raised several research issues for the mobility protocols. First, it is essential to perform cost and scalability analysis of mobility protocols to find out their resource requirement to cope with future expansion. Secondly, mobility protocols have survivability issues and are vulnerable to security threats, since wireless communication media can be easily accessible to intruders. The third challenge in mobile computing is the protection ofsignaling messages against losses due to high bandwidth requirementof multimedia in mobile environments. However, there is lack of existing works that focus on the quantitative analysis of cost, scalability, survivability and security of mobility protocols.In this dissertation, we have performed comprehensive evaluation ofmobility protocols. We have presented tools and methodologies required for the cost, scalability, survivability and security analysis of mobilityprotocols. We have proposed a dynamic scheduling algorithm to protect mobility signaling message against losses due to increased multimedia traffic in mobile environments and have also proposed a mobile networkarchitecture that aims at maximizing bandwidth utilization. The analysis presented in this work can help network engineers compare different mobility protocols quantitatively, thereby choose one that is reliable, secure, survivable and scalable