Delay optimal multichannel opportunistic access

Abstract

The problem of minimizing queueing delay of opportunistic access of multiple continuous time Markov channels is considered. A new access policy based on myopic sensing and adaptive transmission (MS-AT) is proposed. Under the framework of risk sensitive constrained Markov decision process with effective bandwidth as a measure of queueing delay, it is shown that MS-AT achieves simultaneously throughput and delay optimality. It is shown further that both the effective bandwidth and the throughput of MS-AT are two-segment piece-wise linear functions of the collision constraint (maximum allowable conditional collision probability) with the effective bandwidth and throughput coinciding in the regime of tight collision constraints. Analytical and simulations comparisons with the myopic sensing and memoryless transmission (MS-MT) policy which is throughput optimal but delay suboptimal in the regime of tight collision constraints. Index terms-Delay optimal medium access, effective bandwidth, opportunistic access, and constrained risk sensitive Markov decision process. * S. Chen and L. Tong are with the

Spectrum Assignment and Sharing for Delay Minimization in Multi-Hop Multi-Flow CRNs

“…With the consideration of effective channel bandwidth, Chen et. al [15] pointed out that the delay and throughput optimality can be simultaneously achieved under the framework of risk sensitive constrained Markov decision process as a measure of queueing delay. In order to examine whether there is indeed an advantage in using dynamic multi-channel MAC in CRNs, Liu et.…”