A meter-scale 600-Mb/s 2×2 imaging MIMO OOK VLC link using commercial LEDs and Si p-n photodiode array

Abstract

This paper presents a free-space 4-channels imaging multiple-input multiple-output (MIMO) system for On-Off-Keying (OOK) Visible-Light-Communication (VLC) links. An aggregate data-rate of 600 Mb/s is measured over 6 meters link distance with a bit-error-rate (BER) below 10−3 with the 4-channels simultaneously modulated. While the majority of published VLC works to date use components-off-the-shelf (COTS) PIN or Avalanche PDs that require both non-standard and/or higher cost fabrication processes as well as high reverse bias potential, the presented receiver in this paper employs a 2×2 on-chip Nwell/Psub photodiodes (PD) array fabricated in a low cost CMOS-compatible process. To extract high data rate performance out of the proposed CMOS low speed PD array, a 2nd-order LCR equalization is used to compensate for the stringent bandwidth limitation of the PD, measured around 20 MHz and push the speed up to 150 Mbps/channel. With a red light-emitting-diode (LED) array at 650 nm, the 4-channels MIMO setup DC power consumption is 1.38 W, which represents to our knowledge an energy-per-bit record performance for OOK VLC systems of 2.3 nJ/bit.