## 5 Conclusions  
In this work, we addressed two of the main concerns of modern smart home systems, namely the efficient and convenient management of a high density of smart home devices and the improvement of the security of the system. We presented a smart home system architecture that utilizes VLC-enabled LED lighting as location beacons and a smartphone with a camera as the receiver. The system also includes a control application running on the smartphone and a cloud server with a location and connection database of the smart home devices. The proposed system can accurately identify the user's location and orientation to control a smart home device precisely and securely. To address the practical deployment considerations of VLC, we presented the design of a 10 W AC-powered LED lightbulb that integrates VLC functionality with Bluetooth-based wireless control in a standard form factor with an E27 socket. The lightbulb achieves a VLC link distance of up to 3.4 m while maintaining illumination of over 300 lx at a distance of 1.5 m. In addition, we presented an algorithm for calculating the 3D position and orientation of the smartphone using the presented lightbulb and verified the positioning accuracy through measurements, where the system was shown to achieve an average PER of less than 7%.  
However, there are some limitations existing in our proposed VLC-enabled smart home control system which can be addressed in its future iterations. The first limitation is that this VLC lightbulb can be blocked by obstructions when the user is moving in the room. This blocking of visible light may result in incomplete captured patterns or even no patterns for the smartphone camera and lead to difficulty in the decoding process. To solve this limitation, we plan to adopt an image processing algorithm that can decode the transmitted signals with incomplete captured patterns in our future work. In addition, the use of multi-sensor fusion to solve the total blocking issue and further improve system performance is also a possible direction for the future iteration of this system. The second limitation is that the proposed smart home control system only combines Bluetooth-supported devices and lacks other types of communication methods such as Wi-Fi. At present, a large number of smart devices in the market support Wi-Fi-based communication networks. Therefore, combining Wi-Fi-supported devices into our proposed control system is a significant direction for increasing the possibility of real-world application. Moreover, we plan to expand the scope of the proposed system to include robots as autonomous SHS monitoring agents, utilizing the highly accurate locations from the LED lights to help the robots with navigation and control planning.  
Conceptualization, C.P.Y., B.H. and B.X.; methodology, B.H., B.X. and Y.W.; software, B.H. and H.C.C.; validation, B.X., Y.W. and H.C.C.; writing--original draft preparation, B.X. and B.H.; writing--review and editing, C.P.Y. and B.H.; supervision, C.P.Y.; project administration, C.P.Y. and B.H.; funding acquisition, C.P.Y. All authors have read and agreed to the published version of the manuscript.  
This work was funded by the Foshan-HKUST Projects under the Government of Foshan Municipal City, grant number FSUST20-SHCIRI05C; the Project of Hetao Shenzhen-Hong Kong Science and Technology Innovation Cooperation Zone, grant number HZQB-KCZYB-2020083; the Hong Kong Research Grants Council under General Research Fund (GRF) project, grant number 16215620; and the HKUST-Qualcomm Joint Innovation and Research Laboratory.  
Not applicable.  
\begin{table}
\begin{tabular}{c c c c c c} \hline \hline
**Location** & **Direction Angles** & **x0 (cm)** & **y0 (cm)** & **z0 (cm)** & **PER** \\ \hline Position 1 & \(\varphi_{\text{x}}=40^{\circ}\), \(\varphi_{\text{y}}=0^{\circ}\), \(\varphi_{\text{z}}=0^{\circ}\) & \(-151\) & \(0\) & \(81\) & \(6.72\%\) \\ \hline Position 2 & \(\varphi_{\text{x}}=-23^{\circ}\), \(\varphi_{\text{y}}=-39^{\circ}\), \(\varphi_{\text{z}}=90^{\circ}\) & \(-117\