DMCA
Optimality of Myopic Sensing in Multichannel Opportunistic Access (2008)
Cached
Download Links
| Citations: | 110 - 37 self |
BibTeX
@MISC{Ahmad08optimalityof,
author = {Sahand Haji Ali Ahmad and Mingyan Liu and Tara Javidi and Qing Zhao and Bhaskar Krishnamachari},
title = {Optimality of Myopic Sensing in Multichannel Opportunistic Access},
year = {2008}
}
Share
 |
 |
 |
 |
||
OpenURL
Abstract
We consider opportunistic communication over multiple channels where the state (“good ” or “bad”) of each channel evolves as independent and identically distributed Markov processes. A user, with limited channel sensing and access capability, chooses one channel to sense and subsequently access (based on the sensed channel state) in each time slot. A reward is obtained whenever the user senses and accesses a “good ” channel. The objective is to design an optimal channel selection policy that maximizes the expected total (discounted or average) reward accrued over a finite or infinite horizon. This problem can be cast as a Partially Observable Markov Decision Process (POMDP) or a restless multi-armed bandit process, to which optimal solutions are often intractable. We show in this paper that a myopic policy that maximizes the immediate one-step reward is always optimal when the state transitions are positively correlated over time. When the state transitions are negatively correlated, we show that the same policy is optimal when the number of channels is limited to 2 or 3, while presenting a counterexample for the case of 4 channels. This result finds applications in opportunistic transmission scheduling in a fading environment, cognitive radio networks for spectrum overlay, and resource-constrained jamming and anti-jamming.
Keyphrases
myopic sensing multichannel opportunistic access state transition opportunistic transmission scheduling optimal solution partially observable markov decision process good channel user sens myopic policy time slot expected total access capability restless multi-armed bandit process immediate one-step reward optimal channel selection policy limited channel sensing cognitive radio network resource-constrained jamming fading environment spectrum overlay infinite horizon sensed channel state multiple channel opportunistic communication
