Atul Sewaiwar

Color Clustered Multiple-input Multiple-output Visible Light Communication

A novel color clustered optical RGB multiple-input multiple-output (MIMO) system is presented. As visible light can be divided into three primary regions of red, green and blue, data can be modulated and transmitted separately using these three color clusters. Each color cluster comprised of 30 RGB LEDs is modulated using on-off-keying (OOK), and selection combining is performed at the receiver, producing a diversity effect within that color cluster. The simulations demonstrate that the proposed RGB MIMO VLC system provides high performance via a relatively simple design of MIMO. Moreover, the proposed system ensures sufficient illumination from LEDs and offers extended distance if more LEDs are applied.

Smart LED allocation scheme for efficient multiuser visible light communication networks

In a multiuser bidirectional visible light communication (VLC), a large number of LEDs or an LED array needs to be allocated in an efficient manner to ensure sustainable data rate and link quality. Moreover, in order to support an increasing or decreasing number of users in the network, the LED allocation is required to be performed dynamically. In this paper, a novel smart LED allocation scheme for efficient multiuser VLC networks is presented. The proposed scheme allocates RGB LEDs to multiple users in a dynamic and efficient fashion, while satisfying illumination requirements in an indoor environment. The smart LED array comprised of RGB LEDs is divided into sectors according to the location of the users. The allocated sectors then provide optical power concentration toward the users for efficient and reliable data transmission. An algorithm for the dynamic allocation of the LEDs is also presented. To verify its effective resource allocation feature of the proposed scheme, simulations were performed. It is found that the proposed smart LED allocation scheme provides the effect of optical beamforming toward individual users, thereby increasing the collective power concentration of the optical signals on the desirable users and resulting in significantly increased data rate, while ensuring sufficient illumination in a multiuser VLC environment.

Visible light communication based motion detection

In this paper, a unique and novel visible light communication based motion detection is presented. The proposed motion detection is performed based on white light LEDs and an array of photodetectors from existing visible light communication (VLC) links, thus providing VLC with three functionalities of illumination, communication and motion detection. The motion is detected by observing the pattern created by intentional obstruction of the VLC link. Experimental and simulation results demonstrate the validity of the proposed VLC based motion detection technique. The VLC based motion detection can benefit smart devices control in VLC based smart home environments.

3-Gbit/s Indoor Visible Light Communications Using Optical Diversity Schemes

A 3-Gb/s high-speed indoor visible light communication system using optical diversity schemes is presented. A double optical diversity (DOD) scheme in time and frequency is employed with selection combining (SC) on the basis of red, green, and blue (RGB) light-emitting diodes (LEDs). In the proposed scheme, the original data and the delayed versions of this data are transmitted simultaneously by multiplying with orthogonal frequency in order to create diversity effect over the transmission. In addition, RGB LEDs are used for parallel transmission of data, thus resulting in an increase in the data speed. At the receiver, color filters are used to filter out for the desired signal, and SC is performed to obtain the most probable bits. Simulation results demonstrate that the proposed scheme is robust and efficient to overcome the effect of multiple reflections with a link margin of approximately 10 dB, as compared with a conventional on-off keying (OOK) modulation scheme at a bit error rate (BER) of 10-6. Moreover, the scheme achieves a data rate of 3 Gb/s with a BER of 10-6 at a signal-to-noise ratio (SNR) value of 3.6 dB over most locations in an indoor visible light communication (VLC) environment.

Experimental Biomedical EEG Signal Transmission Using VLC

The proliferation of radio frequency (RF) communication technology in biomedical signal transmission is frequently flustered by electromagnetic interference. Even though the flexibility and mobility of RF-based communication have much attraction, the radiation brings damage to hospital equipments and even harm to humans. In this letter, we propose a novel scheme for transmission of electroencephalography (EEG) biomedical signal using a visible light communication (VLC) link. The data transmission is performed in line of sight (LOS) condition using ON-OFF keying nonreturn-to-zero modulation by utilizing all three components, red, green, and blue, of RGB LED. Experiments are carried out for transmitting EEG signals using the VLC link. The transmitter consists of RGB LEDs, and at the receiver side, three photodiodes with red, green, and blue color filters are installed. The experimental results show excellent reliability and accuracy of the proposed scheme.

Smart home technologies using Visible Light Communication

Smart home technologies using visible light data transmission are presented. For multiple devices, orthogonal code based time division duplexed bidirectional Visible Light Communication (VLC) link is employed. The proposed model for smart home is an efficient technology with superior BER performance, subject to locations in a typical smart home environment.

Optical bidirectional beacon based visible light communications

In an indoor bidirectional visible light communications (VLC), a line-of-sight (LOS) transmission plays a major role in obtaining adequate performance of a VLC system. Signals are often obstructed in the LOS transmission path, causing an effect called optical shadowing. In the absence of LOS, the performance of the VLC system degrades significantly and, in particular, at uplink transmission this degradation becomes severe due to design constraints and limited power at uplink devices. In this paper, a novel concept and design of an optical bidirectional beacon (OBB) is presented as an efficient model to counter the performance degradation in a non-line-of-sight (NLOS) VLC system. OBB is an independent operating bidirectional transceiver unit installed on walls, composed of red, green, and blue (RGB) light emitting diodes (LEDs), photodetectors (PDs) and color filters. OBB improves the coverage area in the form of providing additional or alternate paths for transmission and enhances the performance of the VLC system in terms of bit error rate (BER). To verify the effectiveness of the proposed system, simulations were carried out under optical shadowing conditions at various locations in an indoor environment. The simulation results and analysis show that the implementation of OBB improves the performance of the VLC system significantly, especially when the LOS bidirectional transmission paths are completely or partially obstructed.

Smart home multi-device bidirectional visible light communication

Driven by increase in automation, smart homes play an important role in today’s human life. This paper presents a new model for smart home technologies based on multi-device bidirectional visible light communication (VLC). For multiple devices and users, orthogonal code-based wavelength division (color beams) full-duplexed bidirectional VLC link is proposed. The color beams from RGB LEDs are utilized to transmit data and synchronize multi-device transmission. To enhance the performance of the proposed model, receiver diversity is also employed. Performance evaluation reveals that the proposed VLC-based model for smart homes is efficient with superior BER performance in a typical smart home environment except for the far corners. The maximum achievable data rate for each user up to four users is found to be 24xa0Mbps at both uplink and downlink transmissions.

Mobility Support for Full-Duplex Multiuser Bidirectional VLC Networks

In this paper, a novel and unique mobility support scheme for a color-clustered (CC) full-duplex multiuser (MU) bidirectional visible light communication (VLC) network is presented. Mobility is classified into two categories: intercluster and intracluster. In the proposed scheme, the mobility support is efficiently provided using a color filter array (CFA) at the downlink receiver. This CFA gives rise to receiver diversity in the form of selection combining yielding performance improvement. Simulations are conducted in terms of communication delay and frame loss rate relative to user speed and distance. In addition, the bit error rate (BER) performance and the data rate are analyzed in the CC MU VLC network. It is demonstrated that the proposed CFA and receiver diversity based mobility scheme in the CC MU VLC network offers superior performance in terms of BER and data rate in indoor environments.

EEG biomedical signal transmission using visible light communication

The proliferation of radio frequency communication technology in biomedical signal transmission is frequently flustered by electromagnetic interference (EMI). The impact of EMI radiation has the consequences of the reduction in accuracy and reliability. Even though its flexibility and mobility have wide attraction, the radiation brings damage to hospital equipment and even harm to the humans. Biomedical signals such as Electroencephalography (EEG) are most utilized signals, which measures the electrical brain rhythms and has huge capability to identify or determine the cause of diseases. In this paper, we propose a EEG signal transmission system using visible light communication. We employ On-Off Keying (OOK) modulation scheme for transmitting the data and RGB LEDs and photodiodes are used for uplink transmission. Computer simulations are carried out using 10 channels of raw EEG signals with the precision of signal values mainly focused. The results demonstrate that it achieves a Bit Error Rate (BER) better than 1.5×10-5 at a Signal to Noise Ratio (SNR) value of 7 dB, thus exhibiting robust reliability and accuracy compared with conventional transmission methods.