Optical Wireless Communication (OWC) technology is considered to be a potential paradigm in communication area.
In fact, compared to Radio Frequency (RF)-based communication systems, OWC is able to provide high security, low cost and high data rates. Although OWC is more commonly used than most of the classical communication techniques, an inherent challenge that limits this technology, is to establish and maintain close-to-line-of-sight links, as the light signals are highly directional. Specifically, maintaining a line-of-sight (LOS) is very difficult due to the fact that when the signal is exposed to the atmosphere or underwater ambient, it is expected to get distorted in its power and hence affects the quality of the transmission. To overcome this, Pointing, Acquisition and Tracking (PAT) has been proposed to maintain the Line of sight (LOS) for the wireless communication. In general sense, the PAT system can be seen as a closed-loop control system where sensing devices, controllers and actuators are deployed.
Pointing errors caused by atmospheric effects or vibrations are particularly harmful to an optical communication link because of the increase in the fade probability of the signal level. The impact of these phenomena leads to the misalignment between the transmitter and the receiver, decrease in the received signal and increase in Bit Error Rate (BER). Therefore, our goal is to study these effects and propose efficient control strategies algorithms that can reduce the misalignment.
- Al-Alwan, A., Guo, X., N’Doye, I., & Laleg-Kirati, T.-M. (2017). Laser beam pointing and stabilization by fractional-order PID control: Tuning rule and experiments. 2017 IEEE Conference on Control Technology and Applications (CCTA).
- Wenqi Cai, Ibrahima N’Doye, Xiaobin Sun, Asem Alalwan,Wael Alheadary, Mohamed- Slim Alouini, Boon Ooi, Taous-Meriem Laleg-Kirati, “Robust H-infinty pointing error control of free-space optical communication systems", 2nd IEEE Conference on Control Technology and Applications, 2018.
- Ibrahima N’Doye, Sharefa Asiri, Adil Aloufi, Asem Alalwan, and Taous-Meriem Laleg-Kirati, “Intelligent PID based modulating functions for laser beam pointing and stabilization platform: comparison and experimental results", IEEE Transactions on Control Systems Technology. (Accepted)
Keywords: FSO, Optical alignment system, Robust control, Control Design , OWC, PAT