Bandwidth allocation schemes in cellular and wireless local area networks

We discuss a variety of bandwidth allocation schemes in cellular and wireless local area networks. The schemes discussed take the form of call admission control, bandwidth partitioning or channel assignment policies in a cellular network, or the system parameter setting in a wireless local area network. We first discuss how to partition the fixed bandwidth in a cell of a cellular network, to its voice and data users conditioned on a fixed number of admitted voice calls. A linear programming problem is set up for optimizing voice packet delay and data bandwidth, with the constraint on a maximum tolerable voice packet loss and delay. An ad hoc scheme called Adaptive Round-robin with Threshold is also proposed and analyzed. It is found the two systems have comparable performances. Furthermore, these bandwidth partitioning schemes are also effective in translating packet-level capacity (e.g. number of time slots per frame) to the call-level capacity (e.g. maximum number of calls allowed). We then extend this model to incorporate call-level decisions and optimize both voice call blocking probability and data bandwidth by minimizing a weighted sum of them. The results show that the optimized behavior is either in favor of voice call blocking performance, or in favor of the data bandwidth, based on the weighting factor and the constraint on the handoff dropping probability. We generalize the optimized system as one which has two guard-band thresholds, one for blocking new voice calls and one for dropping handoff calls. Then we move to the topic of the wireless local area networks to discuss the service differentiation in such environment. A p-persistent CSMA/CA MAC protocol is proposed. It combines the features of other service differentiation schemes previously proposed, and has the virtue that the system can be more accurately analyzed for the purpose of parameter setting. Finally, we discuss the channel assignment policies in a hybrid DCA/FCA cellular system. We compare several of this type of systems with two types of traffic and different channel assignment policies, such as buffering new or handoff calls and with channel reservation for handoff calls. The effect on changing the size of DCA and FCA tiers under different traffic loads is also discussed.