CNS Core: Medium: Communication and Networking with Diffused Laser Light

Technological advances have driven an unprecedented acceleration of mobile bandwidth demand, with examples including 4K video streaming, virtual/augmented reality, and autonomous vehicles. It exacerbates the pressure on the rapidly-dwindling radio frequency (RF) spectrum. Visible light communication (VLC) emerges as a promising wireless technology to mitigate the pressure on the RF spectrum. It turns ubiquitous sources of artificial light into wireless access points, promising unparalleled communication bandwidth. Existing VLC research, however, is fundamentally shackled by the limits of light-emitting diodes (LEDs). Their slow response time and low spectral efficiency have resulted in either moderate data rates or centimeter-level transmission distances. The project aims to overcome this limit. It studies the use of diffused laser light as the next-generation transmission medium while qualitatively boosting practical VLC performance to the next level. The project envisions that future indoor (e.g., offices, homes) and outdoor (e.g., car headlights, street lamps) illumination will gradually take advantage of laser diodes because of their superior illumination efficiency. Multiple collocated laser diodes emit light at different wavelengths that are mixed and diffused to generate diffuse white light. The same diffused white light is reused to transmit data at ultra-high speeds, thanks to laser diode's unique properties of high modulation bandwidth and spectrum efficiency. Diffusing laser light not only makes laser light safe for illumination but also mitigates the alignment issues faced by conventional free-space laser communication. Proposed research tackles networking, systems, and optics issues in jointly utilizing diffused laser light for both normal illumination and high-speed, reliable communication, which sets a key departure from prior works that study laser light communication and illumination in isolation. It addresses key research questions including how to build efficient and robust communication link with diffused laser light, how to reconcile the illumination and communication functionality of laser light, and how to leverage links with diffuse laser light for expanded coverage and support of user mobility. The proposed work, if successful, will represent a major paradigm shift in VLC and establish crucial systems pieces to overcome key barriers in systems, networking, and optics to bring VLC links in gigabit data rate range to practical systems. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.