A Simulation Analysis for LED Spatial Distribution for Indoor Visible Light Communication

Abstract Visible light communication (VLC) is a promising technology that can jointly be used to accomplish the typical lighting functionalities of the light-emitting diodes (LEDs) and data transmission, where light intensity can be modulated on a high rate that cannot be noticed by the human eye. In this paper, a VLC simulation framework to study the effect of LEDs’ distributions on different room dimensions is proposed by considering the performance metrics such as light intensity quality in accordance with the International Organization for Standardization (ISO) recommendation, and data transmission efficiency measured in terms of bit error rate (BER). To achieve the abovementioned performance metrics, a VLC communication system is designed that modulates the data, transmits it over the room utilizing the communication channel that is modeled using an accurate ray-tracing algorithm, and receives it by exploiting different receivers that are uniformly distributed in the room. Our work is different from the other published works which either studied the data transmission efficiency or lighting quality but not both. Consequently, this study can be used as a methodological foundation to design an efficient VLC that satisfies the ISO lighting requirement, application-specific BER and quality. Furthermore, a video transmission use case has been demonstrated which shows how the video quality can be significantly improved when increasing the number of transmitters, thus justifying the need for increasing the number of transmitters in scenarios that involves video transmission in an indoor VLC environment.

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A Novel Coding Based Dimming Scheme with Constant Transmission Efficiency in VLC Systems

Applied Sciences ◽

10.3390/app9040803 ◽

2019 ◽

Vol 9 (4) ◽

pp. 803 ◽

Cited By ~ 4

Author(s):

Yu Zuo ◽

Jian Zhang

Keyword(s):

Visible Light ◽

Data Transmission ◽

Visible Light Communication ◽

Transmission Efficiency ◽

Reliable Data ◽

Error Performance ◽

Block Coding ◽

Dimming Control ◽

Transmitted Signal ◽

Simulation Results

Visible light communication (VLC) has attracted tremendous attention due to two functions: communication and illumination. Both reliable data transmission and lighting quality need to be considered when the transmitted signal is designed. To achieve the desired levels of illumination, dimming control is an essential technology applied in VLC systems. In this paper, we propose a block coding-based dimming scheme to construct the codeword set, where dimming control can be achieved by changing the ratio of two levels (ON and OFF) based on on-off keying (OOK) modulation. Simulation results show that the proposed scheme can maintain good error performance with constant transmission efficiency under various dimming levels.

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Research on Secure Debugging Interaction of Sensor Nodes Based on Visible Light Communication

Sensors ◽

10.3390/s21030953 ◽

2021 ◽

Vol 21 (3) ◽

pp. 953 ◽

Cited By ~ 1

Author(s):

Yuanchu Yin ◽

Jiefan Qiu ◽

Zhiqiang Li ◽

Mingsheng Cao

Keyword(s):

Visible Light ◽

Channel Coding ◽

Sensor Node ◽

Source Coding ◽

Visible Light Communication ◽

Propagation Characteristic ◽

Transmission Efficiency ◽

Sensor Nodes ◽

Pulse Interval ◽

Inaccessible Area

When a wireless sensor node’s wireless communication fails after being deployed in an inaccessible area, the lost node cannot be repaired through a debugging interaction that relies on that communication. Visible light communication (VLC) as a supplement of radio wave communication can improve the transmission security at the physical layer due to its unidirectional propagation characteristic. Therefore, we implemented a VLC-based hybrid communication debugging system (HCDS) based on VLC using smartphone and sensor node. For the system’s downlink, the smartphone is taken as the VLC gateway and sends the debugging codes to the sensor node by the flashlight. To improve the transmission efficiency of the downlink, we also propose a new coding method for source coding and channel coding, respectively. For the source coding, we analyze the binary instructions and compress the operands using bitmask techniques. The average compression rate of the binary structure reaches 84.11%. For the channel coding, we optimize dual-header pulse interval (DH-PIM) and propose overlapped DH-PIM (ODH-PIM) by introducing a flashlight half-on state. The flashlight half-on state can improve the representation capability of individual symbols. For the uplink of HCDS, we use the onboard LED of the sensor node to transmit feedback debugging information to the smartphone. At the same time, we design a novel encoding format of DH-PIM to optimize uplink transmission. Experimental results show that the optimized uplink transmission time and BER are reduced by 10.71% and 22%, compared with the original DH-PIM.

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