1,010 research outputs found
Enhanced Optical Wireless Channel For Indoor And Intravehicle Communications: Power Distribution And Signal To Noise Ratio Analysis
Visible light communication—(VLC) provides wide bandwidth and high security
capabilities for free space optical communication. This thesis presents the key concepts,
underlying principles and practical applications of visible light communications. In
particular, this thesis focuses on the received power distribution pattern and signal to noise
ratio for line-of-sight indoor and vehicular applications. Several methods are used to
modify the SNR and power distribution levels. It is shown that in the absence of
obstruction, the optical footprint is nearly circular and offers a platform for large- scale
deployment in commercial environments, which is similar to micro and Pico cells.
By studying various kinds of commonly used VLC channel analysis: diffuse and
line of sight channels, a simple improved indoor and intra-vehicular VLC transmission
model for power distribution and SNR is presented. Employing optical wireless
communications within the vehicle not only enhances user mobility, but also alleviates
radio frequency interference, and lowers system cost through the utilization of license free
spectrum. Moreover, a solution to increase the received power by changing the semi angle
at half power is presented. The simulation results show the improved received power
distribution and SNR. A VLC system, based on color-shift-keying (CSK) modulation and
code-division multiple-access (CDMA) is presented. CSK–CDMA VLC system is used to
enhance the VLC system capacity and mitigate single color light interference, which allows
multiple users to access the network
Employing VLC technology for transmitting data in biological tissue
Abstract. With the development in wireless communication methods, visible light communication (VLC), a subset of Optical Wireless Communication (OWC) has garnered much attention to employ the technology for a secure short-range wireless communication. We present a feasibility study to determine the performance of VLC in short range wireless transmission of data through biological tissue. VLC is a cost efficient and secure means of transmitting high volume of data wirelessly which can considerably reduce the interference issues caused by electromagnetic pulses and external electric fields.
We present a simple measurement approach based on Monte Carlo simulation of photon propagation in tissue to estimate the strength of wireless communication with body implant devices. Using light for communication brings inherent security against unauthorized access of digital data which could be acquired from the low energy body implant devices used for medical diagnosis and other studies.
This thesis discusses the typical components required to establish VLC such as, transmitter, receiver and the channel mediums. Furthermore, two cases of Monte Carlo simulation of photon-tissue interaction are studied to determine a possibility if VLC is a suitable substitute to radio frequency (RF) for a more wireless communication with the body implants. The process of theoretical measurement begins with conversion of light intensity into an electrical signal and an estimation of achievable data rate through a complex heterogeneous biological tissue model.
The theoretically achieved data rates of the communication were found to be in the order of megabits per second (Mbps), ensuring a possibility to utilize this technology for short range reliable wireless communication with a wider range and application of implant medical devices. Biophotonics.fi presents a computational simulation of light propagation in different types of computational tissue models comprehensively validated by comparison with the team’s practical implementation of the same setup. This simulation is also used in this thesis (5.2.2) to approximate more accurate data rates of communication in case of a practical implementation
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