We investigate a wireless system of multiple cells, each having a downlink shared channel in support of high-speed packet data services. In practice, such a system consists of hierarchically organized entities including a central server, Base Stations (BSs), and Mobile Stations (MSs). Our goal is to improve global resource utilization and reduce regional congestion given asymmetric arrivals and departures of mobile users. For this purpose, we propose a scalable cross-layer framework to

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... e packet-level scheduling, call-level cell-site selection and handoff, and system-level loading balancing based on load, throughput, and channel measurements at different layers. In this framework, an opportunistic scheduling algorithm-the weighted Alpha-Rule-exploits multiuser diversity gain in each cell independently, trading aggregate (mean) downlink throughput for fairness and minimum rate guarantees among MSs. Each MS adapts to its channel dynamics and the load fluctuations in neighboring cells, in accordance with MSs' mobility and their arrivals or departures, by initiating load-aware handoff and cellsite selection. The central server adjusts the scheduling parameters of each cell to coordinate cells' coverage, or cell breathing, by prompting distributed MS handoffs. Across the whole system, BSs and MSs constantly monitor their load, throughput, or channel quality in order to facilitate the overall system coordination. Our specific contributions in such a framework are highlighted by the minimum-rate guaranteed Weighted Alpha-Rule scheduling, the load-aware MS handoff/cell-site selection, and the Media Access Control (MAC)-layer cell breathing. Our evaluations show that the proposed framework can improve the global resource utilization and load balancing, which translates into a smaller blocking rate of MS arrivals without extra resources, while the aggregate throughput remains roughly the same or improved around the hotspots. Our tests also show that the coordinated system is robust to Permission to make digital or hard copies of all or part of this work for personal or classroom use is granted without fee provided that copies are not made or distributed for profit or commercial advantage and that copies bear this notice and the full citation on the first page. To copy otherwise, to republish, to post on servers or to redistribute to lists, requires prior specific permission and/or a fee.