Yuanchen Ma

Intelligent seamless vertical handoff algorithm for the next generation wireless networks

With the rapid development of wide variety of wireless technologies, it is envisioned that the future network will be a convergence of various wireless access technologies providing users with the best anywhere, anytime connections to the Internet. In such environment, it is a critical problem to enable a mobile node to intelligently select wireless access networks and achieve seamless handoff performance. This paper proposes a vertical handoff algorithm which enables a mobile node to intelligently select wireless access network among multiple access technologies, synthetically considering network characteristics and status, such as access bandwidth, response time, data loss, network congestion status, etc, along with access cost and received signal strength (RSS). With the proposed algorithm, wireless network utilization can be optimized according to users strategy and network conditions, and real-time applications can be maintained without packet loss during handoff process. A prototype system is implemented and experimental results are analyzed.

Seamless integration of 3G and 802.11 wireless network

Recently, the interworking of 3G and 802.11 wireless data networks has become a very hot topic. These two kinds of networks have relatively mutual complementary features. The seamless integration of these two networks can surely improve the service availability and flexibility if the end users could do roaming across heterogeneous networks with simple multiple-interface terminals. In this paper, our solution of 3G/802.11integration is expatiated in detail. The solution includes four main nodes: a smart home agent, an 802.11 gateway called PDIF, a 3G gateway called PDSN and a multiple-interface terminal without mobile IP stack. The mobility scheduling module inside the home agent could do the packets scheduling and mobility notification in accord with the handover situations and local policies. The enhanced Mobile IP stack in PDIF and PDSN could work in proxy mode, which could provide mobility support for mobile terminals without mobile IP stack. The detailed description is made on home agent, PDIF, PDSN and mobile terminals. We also present the system performance testing result.

SIP-based Group Service Improvement in CDMA2000 Network

SIP-based multi-party conference service (MFCS) of IETF is adopted by 3GPP2 as conferencing solution. In MFCS, the service content received by multiple participants is the same. So, it is better to use multicast to support MFCS in 3G network, where air resources are limited. In 3GPP2, broadcast multicast service (BCMCS) is standardized allowing optimization of air resources for delivery of uniform content to multiple access terminals in CDMA2000 communication system. In this paper, a new solution is proposed, wherein service mapping is set up between BCMCS and MPCS in CDMA2000 network. By utilizing BCMCS, the radio and access networks resources of the CDMA systems could be saved for MPCS.