Deok-Rae Kim

An Indoor Visible Light Communication Positioning System Using a RF Carrier Allocation Technique

We propose a new indoor positioning system utilizing visible light communication. Intensity modulation/direct detection and carrier allocation methods are utilized in the proposed system. Simultaneous three channel transmissions were applied to calculate the receivers position. The characteristics of the proposed positioning system were investigated through simulation based on the experimental results, and the feasibility of the proposed system was verified by experimentation. The experimental result shows that the average error of estimated positions is reduced to 2.4 cm using adjustment process by normalizing method, which is compared with 141.1 cm without adjustment process.

Outdoor Visible Light Communication for inter- vehicle communication using Controller Area Network

In this paper, we implemented the outdoor Visible Light Communication (VLC) system based on Controller Area Network (CAN) which is normally used in a car, plane, ship, product line control system, medical device and industrial device. For vehicle to vehicle (V2V) or indoor vehicle communication, we used common use device such as head light and back light. We made an application circuit and explained the principle. Also, we found an outdoor VLC problem which is sun light noise and photo detector (PD) saturation problem. Circuits pulse features were demonstrated by signal. Total communication distance was 20 m in the daytime outdoor condition and its experimental transmission performance is presented.

Mitigation of Inter-Cell Interference Utilizing Carrier Allocation in Visible Light Communication System

It is necessary in visible light communication where different information from adjacent cells is distinguishable without inter-cell interference for indoor localization-based services and positioning systems. In order to mitigate inter-cell interference, a carrier allocation-visible light communication system, adopting various carriers among the systems respective cells, is suggested. The effects of inter-cell interference for a single channel and the proposed systems are investigated by experimentation with simultaneous transmissions of QPSK signals.

Inter-cell interference mitigation and indoor positioning system based on carrier allocation visible light communication

A visible light communication system including various signal types transmitted among the systems respective cells needs to be considered as a viable option for indoor localization-based services and positioning systems. In order to mitigate inter-cell interference, a carrier allocation-visible light communication system (CA-VLC), adopting various carriers among the systems respective cells, is suggested. The effects of inter-cell interference for a single channel and the proposed systems are investigated by experimentation with simultaneous transmissions of QPSK signals. Finally, the positioning system based on the CA-VLC is implemented by experimentation with theoretical analysis.

Indoor positioning system based on visible light using location code

In this paper, location estimation algorithm was researched for location based service. In order to mitigate interference, location code was sent by using time division multiplexing. Surface equation can be made by using signal feature distribution. We present experimental results that demonstrate the feasibility of proposed system to estimate local position with a high accuracy.

Indoor positioning system based on carrier allocation visible light communication

The indoor optical positioning system utilizing visible light communication with the modulation method of carrier allocation is proposed. Trilateration method is adopted for determining an estimated position. Even though an inaccurate estimation of distance between transmitter and receiver is caused due to the radiation pattern of LED and incidence angle to receiver, an accuracy of 6-cm positioning error is experimentally achieved using normalization method.

Three-dimensional localization based on visible light optical wireless communication

A novel concept for integrating free space VLC with three-dimensional positioning is presented using RSS. Our demonstration shows that the proposed algorithm can resolve a users position accurately without flickering and inter-cell interference between LED transmitters.

Performance Analysis of Indoor/Outdoor Visible Light Communication System Influenced by External Noise Light

We analyzed the noise effect from artificial light and sunlight on the signal performance in visible light communication systems based on Intensity Modulation/Direct Detection(IM/DD). System performance was experimentally demonstrated by transmitting 50ksysmbol/s QPSK signals at 2MHz sub-carrier. And received signals were analyzed using EVM and RF spectrum. Finally, the system performance was improved by utilizing a visor and we confirm that the outdoor visible light communication was possible using IM/DD method.

Implement of VLC System Based on CAN Communication

In this paper, we implement the VLC system based on CAN communication which is usually used in car, plane, ship, product line control system, medical device and industrial device. We implement the application circuit which is VLC and CAN communication and explain the principle. Circuit`s pulse features are demonstrated by each part`s signal. Total communication distance is 3m and it`s transmission performance is error free.

Transmission performance variation by dimming control in carrier allocation based visible light communication

Signal transmission performance by the variation of bias current to LED is investigated for the purpose of dimming control in carrier allocation based visible light communication system.