| Mobile cellular radio systems have been attracting great interests of industry and researchers. This thesis deals with a major issue in the systems, namely handoff scheme. Several new handoff schemes for the integrated voice/data mobile cellular systems, hierarchical mobile cellular systems and integrated multi-service mobile cellular systems are proposed, and their performance measures are analyzed.After brief introduction of mobile cellular systems, several conventional handoff schemes, namely, non-priority reservation, priority reservation, and queuing priority reservation schemes, are summarized in Chapter 2. Several existing traffic models are also discussed in this chapter.We first study the performance of a preemptive priority handoff scheme in voice/data integrated mobile cellular systems in Chapter 3. A two-dimensional Markov chain models the system. It is shown that, when the data traffic is not very light, the new scheme can provide lower blocking probability for originating voice calls, lower forced termination probability for ongoing voice calls, and shorter average queue length and less average transmission delay for data calls.Next, in Chapter 4, we propose a bandwidth efficient handoff scheme in hierarchical mobile cellular systems. It is shown through extensive comparisons with other candidate handoff strategies that if the total traffic-load of the system is not very heavy, our scheme has the best bandwidth efficiency and can provide better quality of service for mobile subscribers without bringing about too much processing expenses to the system.In Chapter 5, a channel assignment and handoff strategy for multimedia mobile cellular communication systems is proposed. The strategy is modeled and analyzed using a multi-dimensional Markov chain. Important performance measures are obtained. Numerical results show that better QoS can be obtained using the channel allocation and handoff strategy proposed.
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