Citation
Niranjini Rajagopal, Patrick Lazik, Anthony Rowe. "Hybrid Visible Light Communication for Cameras and Low-Power Embedded Devices". ACM Workshop on Visible Light Communication Systems in Conjunction with MobiCom, 7, September, 2014.

Abstract
Visible light communication (VLC) between LED light bulbs and smart-phone cameras has already begun to gain trac- tion for identification and indoor localization applications. To support detection by cameras, the frequencies and data rates are typically limited to below 1kHz and tens of bytes per second (Bps). In this paper, we present a technique for transmitting data from solid-state luminaries, used for inte- rior ambient lighting, simultaneously to both cameras and low-power embedded devices in a manner that is impercep- tible to occupants. This allows the camera communication VLC channel to also act as a higher speed downstream link and low-power wakeup mechanism for energy-constrained devices. Our approach uses Manchester encoding and Bi- nary Frequency Shift Keying (BFSK) to modulate the high- speed data stream and applies duty-cycle adjustment to gen- erate the slower camera communication signal. We explore the trade-off between the performance of the two communi- cation channels. Our hybrid communication protocol is also compatible with existing IR receivers. This allows lights to communicate with low-cost commodity chipsets and control home appliances such as TVs, AV receivers, AC window units, etc. We show that we are able to reliably simultane- ously transmit low-speed data at 1.3 Bps to camera enabled devices and higher-speed data at 104 Bps to low-power em- bedded devices. Since the majority of energy in many RF communication protocols often goes towards media access and receiving, VLC-triggered wakeup can significantly de- crease system energy consumption. We also demonstrate a proof-of-concept wakeup circuit that consumes less then 204uA and can be triggered in less then 10ms.

Electronic downloads

• http://dx.doi.org/10.1145/2643164.2643173
• https://www.src.org/library/publication/p071318/. (Link to paper on SRC website.)

• HTML

  Niranjini Rajagopal, Patrick Lazik, Anthony Rowe. <a
  href="http://www.terraswarm.org/pubs/345.html"
  >Hybrid Visible Light Communication for Cameras and
  Low-Power Embedded Devices</a>, ACM Workshop on
  Visible Light Communication Systems in Conjunction with
  MobiCom, 7, September, 2014.

• Plain text

  Niranjini Rajagopal, Patrick Lazik, Anthony Rowe.
  "Hybrid Visible Light Communication for Cameras and
  Low-Power Embedded Devices". ACM Workshop on Visible
  Light Communication Systems in Conjunction with MobiCom, 7,
  September, 2014.

• BibTeX

  @inproceedings{RajagopalLazikRowe14_HybridVisibleLightCommunicationForCamerasLowPowerEmbedded,
      author = {Niranjini Rajagopal and Patrick Lazik and Anthony
                Rowe},
      title = {Hybrid Visible Light Communication for Cameras and
                Low-Power Embedded Devices},
      booktitle = {ACM Workshop on Visible Light Communication
                Systems in Conjunction with MobiCom},
      day = {7},
      month = {September},
      year = {2014},
      abstract = {Visible light communication (VLC) between LED
                light bulbs and smart-phone cameras has already
                begun to gain trac- tion for identification and
                indoor localization applications. To support
                detection by cameras, the frequencies and data
                rates are typically limited to below 1kHz and tens
                of bytes per second (Bps). In this paper, we
                present a technique for transmitting data from
                solid-state luminaries, used for inte- rior
                ambient lighting, simultaneously to both cameras
                and low-power embedded devices in a manner that is
                impercep- tible to occupants. This allows the
                camera communication VLC channel to also act as a
                higher speed downstream link and low-power wakeup
                mechanism for energy-constrained devices. Our
                approach uses Manchester encoding and Bi- nary
                Frequency Shift Keying (BFSK) to modulate the
                high- speed data stream and applies duty-cycle
                adjustment to gen- erate the slower camera
                communication signal. We explore the trade-off
                between the performance of the two communi- cation
                channels. Our hybrid communication protocol is
                also compatible with existing IR receivers. This
                allows lights to communicate with low-cost
                commodity chipsets and control home appliances
                such as TVs, AV receivers, AC window units, etc.
                We show that we are able to reliably simultane-
                ously transmit low-speed data at 1.3 Bps to camera
                enabled devices and higher-speed data at 104 Bps
                to low-power em- bedded devices. Since the
                majority of energy in many RF communication
                protocols often goes towards media access and
                receiving, VLC-triggered wakeup can significantly
                de- crease system energy consumption. We also
                demonstrate a proof-of-concept wakeup circuit that
                consumes less then 204uA and can be triggered in
                less then 10ms.},
      URL = {http://terraswarm.org/pubs/345.html}
  }
  

Posted by Barb Hoversten on 14 Aug 2014.
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