41 research outputs found
Non-Orthogonal Multiple Access for FSO Backhauling
We consider a free space optical (FSO) backhauling system which consists of
two base stations (BSs) and one central unit (CU). We propose to employ
non-orthogonal multiple access (NOMA) for FSO backhauling where both BSs
transmit at the same time and in the same frequency band to the same
photodetector at the CU. We develop a dynamic NOMA scheme which determines the
optimal decoding order as a function of the channel state information at the CU
and the quality of service requirements of the BSs, such that the outage
probabilities of both BSs are jointly minimized. Moreover, we analyze the
performance of the proposed NOMA scheme in terms of the outage probability over
Gamma-Gamma FSO turbulence channels. We further derive closed-form expressions
for the outage probability for the high signal-to-noise ratio regime. Our
simulation results confirm the analytical derivations and reveal that the
proposed dynamic NOMA scheme significantly outperforms orthogonal transmission
and existing NOMA schemes.Comment: This paper has been submitted to IEEE WCNC 201
Opportunities of Optical Spectrum for Future Wireless Communications
The requirements in terms of service quality such as data rate, latency,
power consumption, number of connectivity of future fifth-generation (5G)
communication is very high. Moreover, in Internet of Things (IoT) requires
massive connectivity. Optical wireless communication (OWC) technologies such as
visible light communication, light fidelity, optical camera communication, and
free space optical communication can effectively serve for the successful
deployment of 5G and IoT. This paper clearly presents the contributions of OWC
networks for 5G and IoT solutions.Comment: 2019 International Conference on Artificial Intelligence in
Information and Communication (ICAIIC
A VLC Smartphone Camera based Indoor Positioning System
We present a real-time indoor visible light positioning system based on the optical camera communication, where the coordinate data in the ON–OFF keying format is transmitted via light-emitting diode-based lights and captured using a smartphone camera. The position of the camera is estimated using a novel perspective- n -point problem algorithm, which determines the position of a calibrated camera from n 3D -to-2D point correspondences. The experimental results show that the proposed system offers mean position errors of 4.81 and 6.58 cm for the heights of 50 and 80 cm, respectively
OFDM-PWM scheme for visible light communications
In this paper, we propose an improved hybrid optical orthogonal frequency division multiplexing (O-OFDM) and pulse-width modulation (PWM) scheme for visible light communications. In this scheme, a bipolar O-OFDM signal is converted into a PWM format where the leading and trailing edges convey the frame synchronization and modulated information, respectively. The proposed scheme is insensitive to the non-linearity of the light emitting diode (LED) as LEDs are switched ‘on’ and ‘off’ between two points. Therefore, the tight requirement on the high peak-to-average-power-ratio (PAPR) in O-OFDM is no longer a major issue. The simulation and experimental results demonstrate that the proposed scheme offers an improved bit error rate performance compared to the traditional asymmetrically clipped O-OFDM (ACO-OFDM)
Optical wireless communication systems
The emerging field of optical wireless communication (OWC) systems is seen as potential complementary technology to the radio frequency wireless communications in certain applications. It is deemed as a possible technology in the future 5th Generation communication networks to address the spectrum congestion and improve the system's capacity. More research and developments in OWC is still needed in order for it to be adopted in current and future communication systems. This special issue brings together research papers on OWC covering free space optic, visible communications and ultraviolet communications