Optimal Medium Access Control in Cognitive Radios: A Sequential Design Approach

TL;DR

This paper develops an optimal and asymptotically optimal medium access control strategy for cognitive radios that balances exploration and exploitation without prior knowledge of channel availability, enhancing spectrum utilization.

Contribution

It introduces a novel sequential design approach for cognitive radio MAC protocols that is both optimal and computationally feasible, requiring no prior traffic statistics.

Findings

Optimal strategy derived for unknown channel availability

Asymptotically optimal low-complexity strategy developed

Strategy performs well without prior traffic knowledge

Abstract

The design of medium access control protocols for a cognitive user wishing to opportunistically exploit frequency bands within parts of the radio spectrum having multiple bands is considered. In the scenario under consideration, the availability probability of each channel is unknown a priori to the cognitive user. Hence efficient medium access strategies must strike a balance between exploring the availability of channels and exploiting the opportunities identified thus far. Using a sequential design approach, an optimal medium access strategy is derived. To avoid the prohibitive computational complexity of this optimal strategy, a low complexity asymptotically optimal strategy is also developed. The proposed strategy does not require any prior statistical knowledge about the traffic pattern on the different channels.