Maximizing Expected Achievable Rates for Block-Fading Buffer-Aided Relay Channels

Mohammad Shaqfeh, Ammar Zafar, Hussein AlNuweiri, Mohamed-Slim Alouini

Research output: Contribution to journalArticlepeer-review

12 Scopus citations


In this paper, the long-term average achievable rate over block-fading buffer-aided relay channels is maximized using a hybrid scheme that combines three essential transmission strategies, which are decode-and-forward, compress-and-forward, and direct transmission. The proposed hybrid scheme is dynamically adapted based on the channel state information. The integration and optimization of these three strategies provide a more generic and fundamental solution and give better achievable rates than the known schemes in the literature. Despite the large number of optimization variables, the proposed hybrid scheme can be optimized using simple closed-form formulas that are easy to apply in practical relay systems. This includes adjusting the transmission rate and compression when compress-and-forward is the selected strategy based on the channel conditions. Furthermore, in this paper, the hybrid scheme is applied to three different models of the Gaussian block-fading buffer-aided relay channels, depending on whether the relay is half or full duplex and whether the source and the relay have orthogonal or non-orthogonal channel access. Several numerical examples are provided to demonstrate the achievable rate results and compare them to the upper bounds of the ergodic capacity for each one of the three channel models under consideration.
Original languageEnglish (US)
Pages (from-to)5919-5931
Number of pages13
JournalIEEE Transactions on Wireless Communications
Issue number9
StatePublished - May 25 2016

Bibliographical note

KAUST Repository Item: Exported on 2020-10-01
Acknowledgements: This work was supported by the National Priorities Research Program through the Qatar National Research Fund (a member of Qatar Foundation) under Grant 8-1531-2-651. The work of M.-S. Alouini was supported by the King Abdullah University of Science and Technology.


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