Cloud radio access networks: Uplink channel estimation and downlink precoding

Osvaldo Simeone, Jinkyu Kang, Joonkhyuk Kang, Shlomo Shamai Shitz

Research output: Chapter in Book/Report/Conference proceedingChapter


This chapter explores the problem of optimal functional split between remote radio heads (RRHs) and baseband unit (BBU) at the physical (PHY) layer by focusing on the two key baseband operations of channel estimation and channel encoding/precoding. It recalls that alternative functional splits are envisaged to be potentially advantageous in the presence of significant fronthaul capacity constraints. For the uplink, the chapter compares the standard implementation in which all baseband processing, including channel estimation, is performed at the BBU, with an alternative architecture in which channel estimation, along with the necessary frame synchronization and resource demapping, is instead implemented at the RRHs. The chapter discusses the downlink, where one can contrast the standard cloud radio access network (C-RAN) implementation with an alternative one in which channel encoding and precoding are applied at the RRHs, while the BBU retains the function of designing the precoding matrices based on the available channel state information.

Original languageEnglish (US)
Title of host publicationSignal Processing for 5G
Subtitle of host publicationAlgorithms and Implementations
PublisherWiley-IEEE Press
Number of pages25
ISBN (Electronic)9781119116493
ISBN (Print)9781119116462
StatePublished - Jan 1 2017

All Science Journal Classification (ASJC) codes

  • General Engineering
  • General Computer Science


  • Channel encoding
  • Channel precoding
  • Cloud radio access networks
  • Downlink precoding
  • Remote radio heads
  • Uplink channel estimation


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