In this proposal the principal investigators (PIs) study intercellular coordination schemes for the efficient utilization of the wireless network capacity incorporating QoS constraints. The framework that the PIs assume throughout is a cellular mobile system in which each cell contains a base station that communicates with mobile users in that cell. This communication is done over a given set of channels, where a channel is defined to be a generic network resource (e.g., time-slots, frequency bands, etc.). The PIs then propose to develop intercellular coordination schemes for managing channels in two categories:
Inter-cellular coordination for Incomplete Reuse: The PIs will study dynamic channel allocation schemes that involve localized coordination between neighboring cells. Specifically, they will investigate a novel scheme called channel sharing, where mobile users have access to channels that are preassigned to groups of cells called meta-cells. This scheme relies only on localized information and hence has significant practical value. The PIs describe their proposed sharing scheme in some detail, and show preliminary results which indicate that the scheme has the potential for significantly improving network performance, and can be used to help reduce QoS violations of existing users in the network.
Inter-cellular coordination for complete reuse: Since the problem of globally scheduling all transmission requests with complete success in a cellular system is in general intractable, the PIs propose to tackle the problem by developing a simple intercellular coordination technique. In this technique, they propose to make a priori coordination arrangements between cells, so that a certain set of carrier frequencies in each cell are assigned to communicate at full power, while others communicate at a predetermined reduced power level. The PIs call this scheme a primary-secondary coordination scheme. For this scheme, they have shown preliminary work that the optimal scheduling solution based on user location, is in the form of a simple bang-bang control, which makes the scheme practically appealing. They propose to study joint optimization problems that maximize the network throughput under both location and QoS based constraints. Finally, the PIs propose to investigate the possibility of combining the ideas of sharing and primary-secondary coordination, to increase further the network utilization.
This award includes a subcontract to Mischa Schwartz, Columbia University.
