RETRO: Retroreflector Based Visible Light Indoor Localization for Real-time Tracking of IoT Devices

Sihua Shao, Abdallah Khreishah, Issa Khalil

Research output: Chapter in Book/Report/Conference proceedingConference contribution

31 Scopus citations


Indoor localization is very important to enable Internet-of-things (IoT) applications. Visible light communication (VLC)-based indoor localization approaches enjoy many advantages, such as utilization of existing ubiquitous lighting infrastructure, high location and orientation accuracy, and no interruption to RF -based devices. However, existing VLC-based localization methods lack a real-time backward channel from the device to landmarks and necessitate computation at the device, which make them unsuitable for real-time tracking of small IoT devices. In this paper, we propose and prototype a retroreflector-based visible light localization system (RETRO), that establishes an almost zero-delay backward channel using a retroreflector to reflect light back to its source. RETRO localizes passive IoT devices without requiring computation and heavy sensing (e.g., camera) at the devices. Multiple photodiodes (i.e., landmarks) are mounted on any single unmodified light source to sense the retroreflected optical signal (i.e., location signature). We theoretically derive a closed-form expression for the reflected optical power related to the location and orientation of the retroreflector, and validate the theory by experiments. The characterization of received optical power is applied to a received signal strength indicator and trilateration based localization algorithm. Extensive experiments demonstrate centimeter-level location accuracy and single-digit angular error.

Original languageEnglish (US)
Title of host publicationINFOCOM 2018 - IEEE Conference on Computer Communications
PublisherInstitute of Electrical and Electronics Engineers Inc.
Number of pages9
ISBN (Electronic)9781538641286
StatePublished - Oct 8 2018
Event2018 IEEE Conference on Computer Communications, INFOCOM 2018 - Honolulu, United States
Duration: Apr 15 2018Apr 19 2018

Publication series

NameProceedings - IEEE INFOCOM
ISSN (Print)0743-166X


Other2018 IEEE Conference on Computer Communications, INFOCOM 2018
Country/TerritoryUnited States

All Science Journal Classification (ASJC) codes

  • General Computer Science
  • Electrical and Electronic Engineering


  • Indoor localization
  • Retroreflector
  • Visible light


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