Integrated service model in heterogeneous wireless networks

The development of Next Generation Network (NGN) will integrate various different networks and services into one single All-IP based architecture. IMS promises a cost-effective evolution path to NGN service convergence. Great effort has been expended to integrate fixed and mobile network services. A variety of wireless technologies are being deployed to provide IP based services. Heterogeneity is becoming the norm of future wireless world. We propose and evaluate the architectures and algorithms that enable a rich set of services to be offered efficiently in widely heterogeneous next generation mobile networks. We address user and device mobility across multiple network types, open service architectures that support user privacy and control algorithms to protect the network from transient overload that may affect its processing resources.;We propose a framework and implement a modular mobile access router system. The Multiple Backhaul Mobile Access Router aims to provide high capacity and high performance Internet access for emerging mobile wireless applications. A set of backhaul interface monitoring APIs are provided to support flexible handover policies. We present the experimental results to validate the performance of our mobile access router and illustrate tradeoffs when designing handover policies. In addition, we extend the framework to support application configurable striping protocols and implement the per user striping protocol on the MAR. The experimental results validate the performance of our mobile access router and different switching policies integration. With the above enhancements, the MAR is able to provide aggregated communication channels to the users, and enhance reliability by switching wireless interfaces when it is necessary.;Location based services are becoming increasingly important to the success and attractiveness of next generation wireless systems. However, a natural tension arises between the need for user privacy and the flexible use of location information. We present a framework to support privacy enhanced location based services and a practical LBS system implementation. The key idea behind the system is to hierarchically encrypt location information under different keys, and distribute the appropriate keys only to group members with the necessary permission. Furthermore, the intrinsic hierarchical property of location information motivates the design to exploit the advantages of hierarchical key distribution. Hierarchical location information coding offers flexible location information access which enables a rich set of location based services. We propose a key tree rebalancing algorithm to maintain the re-keying performance of the group key management. Our load tests show such a system is highly practical with good efficiency and scalability.;The signaling in IMS is based on the SIP which is already widely used for signaling in VoIP networks. IMS networks are expected to have a significant increase in their signaling loads, and a corresponding higher computational cost on network elements. In the mean time, by introducing IP connectivity, 3G networks are vulnerable to new adversaries. In order to maintain the service requirements of future integrated wireless networks, while reducing the cost of the network, we have to protect the processing servers from overload in the core network. We design, analyze and implement overload control algorithms at different layers. We show the performance results in an experimental SIP network and provide practical suggestions for deploying such systems in all IP based networks. We propose a framework to design overload control in kernel when IPSec is used to protect the signaling exchange. In addition we evaluate the system under malicious traffic injection with IPSec. Our results show the different performance aspects under real SIP networks which is applicable for all IP based networks in the future.