The multiple backhaul mobile access router (MAR) can provide high capacity and high performance Internet access for emerging mobile wireless applications. In this paper we improve the MAR with the capability to stripe traffic from clients over multiple available network devices. The MAR allows different backhauls to be used simultaneously and accommodates diverse policies. We present experimental results to validate the per user striping performance of our MAR and explore trade-offs when integrating switching policies. 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(LBS) 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. In this paper we present a framework to support privacy enhanced location based services. We classify the services according to several basic criteria and we propose a hierarchical key distribution method to support these services. 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. Four methods are proposed to deliver hierarchical location information while maintaining privacy. We propose a key tree rebalancing algorithm to maintain the re-keying performance of the group key management. Furthermore, we present a practical LBS system implementation. Hierarchical location information coding offers flexible location information access which enables a rich set of location based services. Our load tests show such a system is highly practical with good efficiency and scalability.

The multiple backhaul mobile access router aims to provide high capacity and high performance Internet access for emerging mobile wireless applications. In this paper we describe the framework and implementation of a modular mobile access router system. 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.

Location based services are becoming increasingly important to the success and attractiveness of next generation wireless systems. Service providers will use location information to introduce new services and greatly enhance many existing services. Maintaining location privacy is an important requirement that must be met for these services to be widely deployed. It is a challenge to maintain location privacy while still providing the flexible access to location information required to enable a rich set of location based services. In this paper we define a high-level architecture for providing LBS and classify services according to several basic criteria. To support these services we propose a hierarchical key distribution method. Four methods are proposed to deliver hierarchical location information while maintaining privacy. We evaluate the efficiency of the system in terms of message delivery and key management overhead