Document Type
Dissertation
Date of Award
12-31-2022
Degree Name
Doctor of Philosophy in Electrical Engineering - (Ph.D.)
Department
Electrical and Computer Engineering
First Advisor
Roberto Rojas-Cessa
Second Advisor
Nirwan Ansari
Third Advisor
Abdallah Khreishah
Fourth Advisor
Xuan Liu
Fifth Advisor
Nattapong Kitsuwan
Abstract
Nondirect Line-of-Sight Free-Space Optical Communications (NLoS-FSOC) uses diffuse reflected light to establish communication between two or more stations that are with or without line-of-sight (LoS) to each other. Different from free-space optical communications (FSOC), NLoS-FSOC uses a diffuse reflector (DR) between a transmitter and a receiver so that LoS is not required between them but between the station and the DR. Unlike a mirror, the DR reflects the incident light to all directions and except to itself. That multidirectional reflection broadcast the optical transmission to all receivers with LoS to the DR. The optical broadcast channel establishes a true optical local area network (OLAN) where an optical transmission is detectable to the stations in the OLAN and all stations in the OLAN are able to communicate with the others without re-pointing and re-alignment of their transceiver. NLoS-FSOC is capable of achieving transmissions at high data rates that are common to optical signals and with low power consumption. Therefore, learning more from this novel paradigm is of interest.
This work analyzes the different properties of NLoS-FSOC and shows how those properties facilitate communications between stations and a ground optical base station (OBS) that connects them to the Internet or other stations in the OLAN. The challenges to realizing NLoS-FSOC are identified and a model of an OLAN that can overcome those challenges is proposed. The robustness of NLoS-FSOC allows extending its application to a mix of Local and Wide-Local Area Networks for the first time. As examples of the analysis of the properties of NLoS-FSOC, this research shows how the angle of incidence in the OLAN and the orientation of the DR determine different properties and the performance of the network. The model is used to estimate the different metrics that characterize the OLAN and its performance, such as range, data rates, and coverage. This work also shows that the properties of NLoS-FSOC demand the design of new medium access control mechanisms for an OLAN as such paradigm also has different properties from radio-frequency (RF) wireless LAN. The end of this dissertation presents experimental results of fundamental tests of NLoS-FSOC.
Recommended Citation
Esubonteng, Paa Kwesi Affir, "Nondirect line-of-sight free-space optical communications and networks" (2022). Dissertations. 1918.
https://digitalcommons.njit.edu/dissertations/1918
