A Cellular Wireless Local Area Network with QoSGuarantees for

A wireless local area network (WLAN) or a cell with quality-of-service (QoS) guarantees for various types of traac is considered. A centralized (i.e., star) network is adopted as the topology of a cell which consists of a base station and a number of mobile clients. Dynamic Time Division Duplexed (TDD) transmission is used, and hence, the same frequency channel is time-shared for downlink and uplink transmissions under the dynamic control of the base station. We divide traac into two classes: class I (real-time) and II (non-real-time). Whenever there is no eligible class-I traac for transmission, class-II traac which requires no delay-bound guarantees is transmitted, while uplink transmissions are controlled with a reservation scheme. Class-I traac which requires a bounded delay and guaranteed throughput is handled with the framing strategy 1] which consists of a smoothness traac model and the stop-and-go queueing scheme. We also establish the admission test for adding new class-I connections. We present a modiied framing strategy for class-I voice uplink transmissions which utilizes the wireless link eeciently at the cost of some packet losses. Finally, we present the performance (average delay and throughput) evaluation of the reservation scheme for class-II traac using both analytical calculations and simulations. Any opinions, ndings, and conclusions or recommendations expressed in this publication are those of the authors and do not necessarily reeect the views of the funding agency.