Modeling and analysis of channel transferability in mobile computing environments

Mobile computers use wireless channels to communicate with other computers. Ef-cient channel allocation is at the heart of an eecient mobile computing system. The nite number of channels should be eeciently allocated to maximize throughput and to avoid co-channel interference. Temporal variations in channel demand (load) require channel allocation to adapt dynamically to the changing demand. The presence of load imbalance does not automatically imply the usefulness of channel transfer. In this paper we present a probabilistic analysis of the temporal imbalance in channel demand. The eeectiveness of channel transfer depends on the duration for which the imbalance persists. This duration is innuenced in part by the velocity of mobile units. The wide variance in velocities of the mobile units can be handled by using a hierarchical cellular layout. Bulk channel transfers can be employed to reduce the overheads of channel transfer and to enable the system to quickly adjust to spatial variations in channel demand. The results of our analysis provide guidelines for the design of dynamic distributed channel allocation strategies.