Resource allocation for two source-destination pairs sharing a single relay with a buffer

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

Research output: Contribution to journalArticle

19 Citations (Scopus)


In this paper, we obtain the optimal resource allocation scheme in order to maximize the achievable rate region in a dual-hop system that consists of two independent source-destination pairs sharing a single half-duplex relay. The relay decodes the received information and possesses buffers to enable storing the information temporarily before forwarding it to the respective destination. We consider both non-orthogonal transmission with successive interference cancellation at the receivers and orthogonal transmission. Also, we consider Gaussian block-fading channels and we assume that the channel state information is known and that no delay constraints are required. We show that, with the aid of buffering at the relay, joint user-and-hop scheduling is optimal and can enhance the achievable rate significantly. This is due to the joint exploitation of multiuser diversity and multihop diversity in the system. We provide closed-form expressions to characterize the average achievable rates in a generic form as functions of the statistical model of the channels. Furthermore, we consider sub-optimal schemes that exploit the diversity in the system partially and we provide numerical results to compare the different schemes and demonstrate the gains of the optimal one.

Original languageEnglish
Article number6783948
Pages (from-to)1444-1457
Number of pages14
JournalIEEE Transactions on Communications
Issue number5
Publication statusPublished - May 2014



  • Optimal resource allocation
  • achievable rate region
  • block-fading channels
  • joint user-and-hop scheduling
  • relay with a buffer
  • shared relay

ASJC Scopus subject areas

  • Electrical and Electronic Engineering

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