Overlay cognitive radios with channel-aware adaptive link selection and buffer-aided relaying

Mohammad Shaqfeh, Ammar Zafar, Hussein Alnuweiri, Mohamed Slim Alouini

Research output: Contribution to journalArticle

11 Citations (Scopus)


The aim of this work is to maximize the long-term average achievable rate region of a primary and a secondary source-destination pairs operating in an overlay setup over block-fading channels. To achieve this objective, we propose an opportunistic strategy to grant channel access to the primary and secondary sources based on the channel conditions in order to exploit the available multiple-link diversity gains in the system. The secondary source has causal knowledge of the primary messages and it acts as a relay of the primary source in return for getting access to the channel. To maximize the gains of relaying, the relay and destination are equipped with buffers to enable the use of channel-aware adaptive link selection. We propose and optimize different link selection policies and characterize their expected achievable rates. Also, we provide several numerical results to demonstrate the evident mutual benefits of buffer-aided cooperation and adaptive link selection to the primary and the secondary source-destination pairs.

Original languageEnglish
Article number7130604
Pages (from-to)2810-2822
Number of pages13
JournalIEEE Transactions on Communications
Issue number8
Publication statusPublished - 1 Aug 2015


  • Adaptive link selection
  • Blockfading channels
  • Buffer-aided relaying
  • Opportunistic communication
  • Overlay cognitive radios

ASJC Scopus subject areas

  • Electrical and Electronic Engineering

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