Yong-Hwan Son

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.

Three-Dimensional Visible Light Indoor Localization Using AOA and RSS With Multiple Optical Receivers

A novel concept is proposed for integrating optical wireless visible light communications with 3-D indoor positioning using a single transmitter and multiple tilted optical receivers. We modeled a channel link, which was based on the transmitter and receiver characteristic data obtained in this experiment. The proposed 3-D positioning algorithm is based on gain difference, which is a function of the angle of arrival and the received signal strength. Our demonstration shows that the proposed algorithm can determine accurate positions, including height, without intercell interference.

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.

Full Colorless WDM-Radio Over Fiber Access Network Supporting Simultaneous Transmission of Millimeter-Wave Band and Baseband Gigabit Signals by Sideband Routing

A new wavelength division multiplexed-radio over fiber (WDM-RoF) access network scheme supporting the simultaneous transmission of a 1.25-Gb/s wired data as well as a 1.25-Gb/s wireless data is proposed in this paper. An optical carrier suppression effect and sideband routing using the multiplexing of arrayed waveguide grating (AWG) with 50-GHz channel spacing are utilized to generate a millimeter wave band carrier. These techniques make the proposed architecture transmit both a wired data and a wireless one at the same time. A reflective semiconductor optical amplifier (RSOA) is employed at both central office and base station so that this architecture is operated colorlessly. Error free transmissions (BER of 10-9 ) of both downlink and uplink are achieved simultaneously. A rare impact of downlink transmission on the performance of uplink data is observed due to the usage of the unmodulated light.

Channel Assignment Technique for RF Frequency Reuse in CA-VLC-Based Accurate Optical Indoor Localization

We propose a novel method of frequency assignment for the purpose of efficient RF frequency reuse in an indoor positioning system based on carrier allocation visible light communication. We investigate the performance characteristics of hexagonal, square, and rectangular cell layouts. We experimentally demonstrate a real-time indoor positioning system and make analytical comparisons between different cell layouts to determine the optimum frequency assignment for LED-based coverage.

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.

Colorless two different gigabit data access transmissions using optical double sideband suppressed carrier and optical sideband slicing

A wavelength division multiplexed (WDM) radio over fiber access network architecture, capable of simultaneously transmitting both 63 GHz wireless and 2.5 Gb/s wired data, is proposed in this paper. An optical carrier suppression effect and multiplexing of a 50 GHz spaced arrayed waveguide grating are employed to generate a 63 GHz millimeter-wave signal based on WDM. These techniques allow the proposed scheme to simultaneously transmit both wireless and wired data. For full colorless operation, a reflective semiconductor optical amplifier is used at the central office and base station. Error-free simultaneous transmissions [wired data: bit error rate (BER) of 10-12, wireless data: BER of 10-9] of 2.5 Gb/s wired data and 1.25 Gb/s wireless data are achieved. Various impacts of the downlink transmission on the performance of uplink data are investigated with the proposed scheme.

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.