Resource assignment for adaptively modulated interconnected WLANs

Deployment of large wireless local area network (WLAN) in outdoor environment to provide broadband wireless access (BWA) is gaining more attention. Although several standards have been developed for this purpose numerous research and development is going on to improve the performance of the standards. Management of the wireless resource is one of the key ingredients for providing BWA to the users and total number of serviceable users in a certain area. In this thesis we investigate WLANs performance in a metropolitan area using HiperLAN type 2 standard. Inside the LANs user can move from one place to another and user rates are dynamically adjusted based on their distance from the Access Points. To manage the wireless resources of the network we propose resource allocation schemes and evaluate their performance. We develop a generic simulation software for the network and use it for three resource allocation policies namely Minimum Overhead Round Robin (MORR), which does not depend on user's buffer condition, Weighted Minimum Overhead Round Robin (WMORR) which is a function of user buffer as well as the waiting time for transmission opportunity and Weighted Round Robin (WRR) which is a function of user buffer only. We evaluate average buffer occupancy, packet delivery time, buffer packet drop probability, overhead in downlink and uplink phases for performance comparison of the new allocation schemes. Our results show that the second adaptive resource allocation technique i.e. WMORR outperforms the other tw

Performance evaluation of capacity request and allocation mechanisms for HiperLAN2 wireless LANs

This paper introduces the various capacity request and allocation mechanisms defined for the European Telecommunications Standards Institute (ETSI) high performance radio local area networks (HiperLAN) 2 wireless LANs. Possible policies for operating these mechanisms are proposed and a performance evaluation is carried out in order to assess their suitability for managing delay sensitive (voice and video) and bursty data traffic (Web traffic). The analysis is carried out by simulating different scenarios with single or mixed traffic and different combinations of these mechanisms, and shows that they are sufficiently flexible to accommodate different types of traffic with different quality of service (QoS) requirements. (C) 2001 Elsevier Science B.V. All rights reserved