Exploration vs exploitation for distributed channel access in cognitive radio networks: A multi-user case study

Longwei Wang, Xianfu Chen, Zhifeng Zhao, Honggang Zhang

Research output: Chapter in Book/Report/Conference proceedingConference article in proceedingsScientificpeer-review

6 Citations (Scopus)

Abstract

In this paper, we consider the design of efficient strategies that allow multiple secondary users to choose channels with unknown idle probabilities to sense and access without centralized control. Due to the limited sensing capability of CR, the secondary user cannot sense all the channels simultaneously. How to design intelligent sensing strategy is crucial to track the varying spectrum opportunities. However, the availability probability of each channel is not known a prior. The need to learning the information creates a fundamental trade-off between exploration and exploitation. First, the scenario in which a single cognitive user wishes to opportunistically exploit the availability of idle spectrum is considered. An index based strategy from the classical multi-armed bandit problem is efficient to achieve asymptotically optimal performance. Then, the multiuser case is considered. However, the index based strategy for the single user cannot be applied to multiuser scenario directly. If so, collisions among secondary users degrade the overall network performance greatly. We find that randomized selection of the channel to sense is essential to avoid collisions. We extend the exploration and exploitation idea to the multiuser scenario and come up with a randomization based mixed strategy which takes the activity of other secondary users into consideration in the learning process and at the same time achieves exploration and exploitation tradeoff. Numerical simulation results show that the proposed scheme can achieve near optimal in terms of total network performance as the centralized scenario without any information exchange among cognitive users.

Original languageEnglish
Title of host publication11th International Symposium on Communications and Information Technologies, ISCIT 2011
PublisherIEEE Institute of Electrical and Electronic Engineers
Pages360-365
ISBN (Electronic)978-1-4577-1295-1
ISBN (Print)978-1-4577-1294-4
DOIs
Publication statusPublished - 26 Dec 2011
MoE publication typeA4 Article in a conference publication
Event11th International Symposium on Communications and Information Technologies, ISCIT 2011 - Hangzhou, China
Duration: 12 Oct 201114 Oct 2011

Conference

Conference11th International Symposium on Communications and Information Technologies, ISCIT 2011
CountryChina
CityHangzhou
Period12/10/1114/10/11

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    Wang, L., Chen, X., Zhao, Z., & Zhang, H. (2011). Exploration vs exploitation for distributed channel access in cognitive radio networks: A multi-user case study. In 11th International Symposium on Communications and Information Technologies, ISCIT 2011 (pp. 360-365). [6089953] IEEE Institute of Electrical and Electronic Engineers. https://doi.org/10.1109/ISCIT.2011.6089953