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Proceedings Paper

Indoor communications networks realized through hybrid free-space optical and Wi-Fi links
Author(s): Spencer Liverman; Qiwei Wang; Yu-Chung Chu; Anindita Borah; Songtao Wang; Arun Natarajan; Thinh Nguyen; Alan X. Wang
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Paper Abstract

Recently, free-space optical (FSO) networks have been investigated as a potential replacement for traditional WiFi networks due to their large bandwidth potentials. However, FSO networks often suffer from a lack of mobility. We present a hybrid free-space optical and radio frequency (RF) system that we have named WiFO, which seamlessly integrates free-space optical links with pre-existing WiFi networks. The free-space optical link in this system utilizes infrared LEDs operating at a wavelength of 850nm and is capable of transmitting 50Mbps over a three-meter distance. In this hybrid system, optical transmitters are embedded periodically throughout the ceiling of a workspace. Each transmitter directs an optical signal downward in a diffuse light cone, establishing a line of sight optical link. Line of sight communications links have an intrinsic physical layer of security due to the fact that a user must be directly in the path of transmission to access the link; however, this feature also poses a challenge for mobility. In our system, if the free-space optical link is interrupted, a control algorithm redirects traffic over a pre-existing WiFi link ensuring uninterrupted transmissions. After data packets are received, acknowledgments are sent back to a central access point via a WiFi link. As the demand for wireless bandwidth continues to increase exponentially, utilizing the unregulated bandwidth contained within optical spectrum will become necessary. Our fully functional hybrid free-space optical and WiFi prototype system takes full advantage of the untapped bandwidth potential in the optical spectrum, while also maintaining the mobility inherent in WiFi networks.

Paper Details

Date Published: 29 January 2018
PDF: 5 pages
Proc. SPIE 10559, Broadband Access Communication Technologies XII, 105590H (29 January 2018); doi: 10.1117/12.2292292
Show Author Affiliations
Spencer Liverman, Oregon State Univ. (United States)
Qiwei Wang, Oregon State Univ. (United States)
Yu-Chung Chu, Oregon State Univ. (United States)
Anindita Borah, Oregon State Univ. (United States)
Songtao Wang, Oregon State Univ. (United States)
Arun Natarajan, Oregon State Univ. (United States)
Thinh Nguyen, Oregon State Univ. (United States)
Alan X. Wang, Oregon State Univ. (United States)

Published in SPIE Proceedings Vol. 10559:
Broadband Access Communication Technologies XII
Benjamin B. Dingel; Katsutoshi Tsukamoto; Spiros Mikroulis, Editor(s)

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