Cooperate-and-access spectrum sharing with ARQ-based primary systems

Qiang Li, See Ho Ting, Ashish Pandharipande, Mehul Motani

Research output: Contribution to journalArticleAcademicpeer-review

25 Citations (Scopus)


We consider spectrum sharing in a cognitive radio network where a secondary system co-exists with an automatic repeat-request (ARQ)-based primary system. A cooperate-and-access spectrum sharing protocol is proposed where the secondary system alternates between cooperation and access modes. In the cooperation mode, the secondary system serves as a relay to assist the primary transmission, and in return accumulates credits. The credits allow the secondary system to gain spectrum access by exploiting the ARQ retransmissions of the primary system. We show analytically that through the proposed credit system, as long as the credits accumulated in cooperation mode compensate for the degradation in primary performance during access mode, an equal or higher average throughput is achieved for the primary system than in the case without spectrum sharing, while providing spectrum access opportunities for the secondary system.

Original languageEnglish
Article number6253215
Pages (from-to)2861-2871
Number of pages11
JournalIEEE Transactions on Communications
Issue number10
Publication statusPublished - 2012
Externally publishedYes


  • ARQ
  • cognitive radios
  • Cooperative spectrum sharing
  • relay


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