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Dynamic Load Balancing Through Coordinated Scheduling in Packet Data Systems

01 January 2003

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Thid generation code-division multiple access (CDMA) systems propose to provide packet data service through a high speed shared channel with intelligent and fast scheduling at the base stations. In the current approach base stations schedule independently of other base stations. We consider scheduling schemes in which scheduling deicisons are made jointly for a cluster of cells thereby enhancing performance through interference avoidance and dynamic load balancing. We consider algorithms that assume complete knowledge at the centralized scheduler of the channel quality information from each of the basestations to the terminals as well as a two-tier-scheduling strategy that assumes only the knowledge of the long term channel conditions at the centralized scheduler. We demonstrate that in the case of asymmetric traffic distribution, where load balancing is most pronounced, significant throughput gains can be obtained while the gains in the symmetric case are modest. Since the load balancing is achieved through centralized scheduling, our scheme can adapt to time-varying traffic patterns dynamically.