RF Chain Reduction for MIMO Systems: A Hardware Prototype

Tierui Gong, Nir Shlezinger, Shahar Stein Ioushua, Moshe Namer, Zhijia Yang, Yonina C. Eldar

Research output: Contribution to journalArticlepeer-review

31 Scopus citations


Radio frequency (RF) chain circuits play a major role in digital receiver architectures, allowing passband communication signals to be processed in baseband. When operating at high frequencies, these circuits tend to be costly. This increased cost imposes a major limitation on future multiple-input-multiple-output (MIMO) communication technologies. A common approach to mitigate the increased cost is to utilize hybrid architectures, in which the received signal is combined in analog into a lower dimension, thus reducing the number of RF chains. In this article we study the design and hardware implementation of hybrid architectures via minimizing channel estimation error. We first derive the optimal solution for complex-gain combiners and propose an alternating optimization algorithm for phase-shifter combiners. We then present a hardware prototype implementing analog combining for RF chain reduction. The prototype consists of a specially designed configurable combining board as well as a dedicated experimental setup. Our hardware prototype allows us evaluating the effect of analog combining in MIMO systems using actual communication signals. The experimental study, which focuses on channel estimation accuracy in MIMO channels, demonstrates that using the proposed prototype, the achievable channel estimation performance is within a small gap in a statistical sense from that obtained using a costly receiver in which each antenna is connected to a dedicated RF chain.

Original languageEnglish
Article number9050842
Pages (from-to)5296-5307
Number of pages12
JournalIEEE Systems Journal
Issue number4
StatePublished - 1 Dec 2020
Externally publishedYes


  • Channel estimation
  • hybrid receivers
  • multiple-input-multiple-output (MIMO) communications

ASJC Scopus subject areas

  • Control and Systems Engineering
  • Information Systems
  • Computer Science Applications
  • Computer Networks and Communications
  • Electrical and Electronic Engineering


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