Some Blocking Bounds for Autonomous Channel Selection in Dynamic Spectrum Access

摘要

We consider a circuit-switched network model in which a channel can be utilized at a node if it is idle in all neighbors of the node. The model arises in cellular telephony and various channel assignment strategies have been studied. Motivated by cognitive radio technologies we revisit autonomous channel selection with local information. It is assumed that call chooses an eligible channel uniformly at random from such channels at the time of arrival, and it is blocked if no eligible channel exists. Upper and lower bounds for the blocking probabilities are determined via an auxiliary network process whose equilibrium distribution admits a convenient product form in tree topologies. By way of another approximate characterization, it is argued that random channel selection incurs vanishing loss of optimality as the number of channels and the traffic load increase in proportion.