Optical Wireless Localization Research Articles

Indoor infrared optical wireless localization system with background light power estimation capability.

The indoor user localization function is in high demand for high-speed wireless communications, navigations and smart-home applications. The optical wireless technology has been used to localize end users in indoor environments. However, its accuracy is typically very limited, due to the ambient light, which is relatively strong. In this paper, a novel high-localization-accuracy optical wireless based indoor localization system, based on the use of the mechanism that estimates background light intensity, is proposed. Both theoretical studies and demonstration experiments are carried out. Experimental results show that the accuracy of the proposed optical wireless indoor localization system is independent on the localization light strength, and that an average localization error as small as 2.5 cm is attained, which is 80% better than the accuracy of previously reported optical wireless indoor localization systems.

Experimental demonstration of a novel indoor optical wireless localization system for high-speed personal area networks.

In this Letter, we propose a novel indoor localization system based on optical wireless technology. By using the same architecture as the high-speed full-duplex indoor optical wireless communication system, the "search and scan" process, and the added transmission power and beam footprint information in the "search and scan" message, indoor localization functionality is achieved. Proof-of-concept experiments are carried out, and results show that an average error of <15 cm is achieved with a localization beam size of 1 m. In addition, the major localization-accuracy-limiting factors are analyzed both theoretically and experimentally. When incorporated with the optical wireless communication system, high-speed indoor wireless personal area networks can be achieved.

Experimental Demonstration of a Full-Duplex Indoor Optical Wireless Communication System

In this letter, a high-speed full-duplex indoor optical wireless communication system for both down-link and up-link is experimentally demonstrated. The feasibility of simultaneous error-free (bit-error-rate or BER <; 10-9) operation of both a 10-Gbps down-link and a 500-Mbps up-link with a beam footprint of ~1 m has been demonstrated. Negligible power penalty due to the crosstalk is observed. When this full-duplex system is incorporated with our recently proposed novel optical wireless localization system, error-free operation can be provided over the entire room.

Optical wireless localization

In this paper, we explore the possibility of using directionality of free-space-optical (a.k.a. optical wireless) communications for solving the 3-D localization problem in ad-hoc networking environments. Range-based localization methods either require a higher node density (i.e., at least three other localized neighbors must exist) than required for assuring connectedness or a high-accuracy power-intensive ranging device such as a sonar or laser range finder which exceeds the form factor and power capabilities of a typical ad-hoc node. Our approach exploits the readily available directionality information provided by a physical layer using optical wireless and uses a limited number of GPS-enabled nodes, requiring a very low node density (2-connectedness, independent of the dimension of space) and no ranging technique. We investigate the extent and accuracy of localization with respect to varying node designs (e.g., increased number of transceivers with better directionality) and density of GPS-enabled and ordinary nodes as well as messaging overhead per re-localization. Although denser deployments are desirable for higher accuracy, our method still works well with sparse networks with little message overhead and small number of anchor nodes (as little as 2). We also present a proof-of-concept prototype of our FSO-based localization techniques and show the validity of our approach even with three transceivers per node.