Distributed coordinated transmission with forward-backward training for 5g radio access

Antti Tolli, Hadi Ghauch, Jarkko Kaleva, Petri Komulainen, Mats Bengtsson, Mikael Skoglund, Michael Honig, Eeva Lahetkangas, Esa Tiirola, Kari Pajukoski

Research output: Contribution to journalArticlepeer-review

10 Scopus citations


CoMP transmission and reception have been considered in cellular networks for enabling larger coverage, improved rates, and interference mitigation. To harness the gains of coordinated beamforming, fast information exchange over a backhaul connecting the cooperating BSs is required. In practice, the bandwidth and delay limitations of the backhaul may not be able to meet such stringent demands. These impairments motivate the study of cooperative approaches based only on local CSI that require minimal or no information exchange between the BSs. To this end, several distributed approaches are introduced for CB-CoMP. The proposed methods rely on the channel reciprocity and iterative spatially precoded over-the-air pilot signaling. We elaborate how F-B training facilitates distributed CB by allowing BSs and UEs to iteratively optimize their respective transmitters/receivers based on only locally measured CSI. The trade-off due to the overhead from the F-B iterations is discussed. We also consider the challenge of dynamic TDD where the UE-UE channel knowledge cannot be acquired at the BSs by exploiting channel reciprocity. Finally, standardization activities and practical requirements for enabling the proposed F-B training schemes in 5G radio access are discussed.

Original languageEnglish (US)
Article number8613276
Pages (from-to)58-64
Number of pages7
JournalIEEE Communications Magazine
Issue number1
StatePublished - Jan 2019

ASJC Scopus subject areas

  • Computer Science Applications
  • Computer Networks and Communications
  • Electrical and Electronic Engineering

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