Low-Complexity Buffer-Aided Link Selection with Outdated CSI and Feedback Errors

Nikolaos Nomikos, Themistoklis Charalambous, Demosthenes Vouyioukas, George K. Karagiannidis

Research output: Contribution to journalArticleScientificpeer-review

25 Citations (Scopus)
223 Downloads (Pure)


Buffer-aided relays can improve the diversity of multi-hop networks, however, they increase packet delays. Thus, various delay-aware protocols have been developed, but without considering the transmission diversity. Moreover, most works adopt ideal assumptions, such as symmetric links, perfect Channel State Information (CSI) and error-free feedback channels. So, we propose a Low-Complexity (LoCo) link selection algorithm, herein called LoCo - Link. The proposed algorithm may experience delays during CSI updates, and hence, by using outdated CSI its performance may deteriorate. To alleviate this issue, we next propose a distributed version of LoCo - Link (d - LoCo - Link) dealing with outdated CSI. In both algorithms, the source performs broadcasting towards multiple relays; when the packets are transmitted by a relay to the destination, they are discarded from all other relays. This coordination relies on feedback channels. For non error-free feedback channels, we propose a scheme in which the relays listen to the transmission of the best relay and drop duplicate packets. Results show that LoCo - Link surpasses other algorithms, by decreasing the delay in asymmetric networks. Moreover, d - LoCo - Link avoids diversity losses due to outdated CSI, while the effect of non error-free feedback channels is mitigated by taking advantage of the inter-relay channels.

Original languageEnglish
Pages (from-to)3694 - 3706
Number of pages13
JournalIEEE Transactions on Communications
Issue number8
Early online date29 Mar 2018
Publication statusPublished - Aug 2018
MoE publication typeA1 Journal article-refereed


  • asymmetric links
  • Broadcasting
  • buffer-aided relaying
  • delay
  • Delays
  • diversity
  • Diversity reception
  • low-complexity
  • Markov chains
  • non error-free feedback
  • outdated CSI
  • Protocols
  • Relay networks (telecommunications)
  • Relay selection
  • Signal to noise ratio


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