Exploiting microscopic spectrum opportunities in cognitive radio networks via coordinated channel access

Tao Shu, Marwan Krunz

Research output: Contribution to journalArticlepeer-review

12 Scopus citations


Under the current opportunistic spectrum access (OSA) paradigm, a common belief is that a cognitive radio (CR) can use a channel only when this channel is not being used by any neighboring primary radio (PR). Therefore, the existence of a spectrum opportunity hinges on the absence of active cochannel PRs in a macroscopic region. In this paper, we propose the concept of microscopic spectrum opportunity and show that CRs can still utilize this type of opportunities without interfering with active cochannel PRs, even when these PRs are close to them. As a result, a channel may at the same time present different levels of availability to different CRs. Channel access needs to be carefully coordinated between these CRs to avoid collisions, and more importantly, ensure efficient utilization of the spectrum opportunity from a network's standpoint. In this paper, we formulate the coordinated channel access as a joint power/rate control and channel assignment optimization problem, with the objective of maximizing the sum-rate achieved by the cognitive radio network (CRN). We develop both centralized and distributed algorithms to solve this problem. Our simulation results show that even when accounting for the implementation overhead, significant throughput gain is achieved under our designs.

Original languageEnglish (US)
Article number5499473
Pages (from-to)1522-1534
Number of pages13
JournalIEEE Transactions on Mobile Computing
Issue number11
StatePublished - Nov 2010


  • Cognitive radio networks
  • opportunistic spectrum access
  • power/rate control
  • spectrum leasing.

ASJC Scopus subject areas

  • Software
  • Computer Networks and Communications
  • Electrical and Electronic Engineering


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