Li-Fung Chang

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The Mobile IP (MIP) protocol for IP version 4 provides continuous Internet connectivity to mobile hosts. However, currently it has some drawbacks in the areas of survivability, performance, interoperability with protocols for providing QoS. We have proposed an alternative protocol, Mobile IP with Location Registers (MIP-LR), which overcomes some of these(More)
With the increased subscription rate in Internet services and wireless communications services, a significant amount of traffic for the future wireless communications will be from Internet applications. Therefore, it is important to design a bandwidth-efficient channel allocation scheme to support Internet traffic, which are packet-switched in nature.(More)
{ This paper evaluates the use of packet scheduling to provide multiple service classes for bursty data traac. In particular, we study the performance of the weighted fair queueing algorithm by simulating various scenarios in a packet cellular wireless network similar to an EDGE system. The results show that, due to the burstiness of data traac, traditional(More)
Performance enhancing proxies have drawn considerable interests from the network community as an e ective approach to improve user experience in cellular networks. However, previous research has been focusing on the design of proxy servers as well as the functions that these servers provide. In this paper, we study the placement of proxy servers, especially(More)
TDMA digital transmission is attractive for use in certain types of portable radio systems. A system using this scheme requires wide bandwidth for digital transmission. In multipath media, when delay spread is a significant fraction of the symbol period, the performance of wideband digital transmission systems is severely degraded by having an irreducible(More)