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We report the effect of fog over a free space optical (FSO) communications system employing quadrature phase-shift keying (QPSK) and operating within three carrier wavelengths (0.65 μm, 1.55 μm, and 10 μm). We analyze the power losses on the receiver side and the link performance in terms of the received power level and the Q factor under clear and fog-attenuated atmosphere conditions. Moreover, we...
This paper presents a theoretical investigation and experimental implementation of indoor radio-over-fibre (RoF) using polymer optical fibre. We characterise the system based on the error vector magnitude (EVM), bit error rate (BER), and the signal-to-noise ratio (SNR). We consider three modulation formats of quadrature phase shift keying (QPSK), 16-quadrature amplitude modulation (QAM) and 64-QAM...
This paper reveals that nonlinear propagation is a critical problem for the long term evolution (LTE) technology based on the radio-over-fibre (RoF) system. Therefore, a direct modulation based frequency dithering (DMFD) method is proposed for nonlinear propagation compensation, namely the self phase modulation (SPM) and stimulated brillouin scattering (SBS). We found that DMFD method operates substantially...
This papers investigates the performance of the fast Fourier transform (FFT) sizes- 64, 128, 256, 512 and 1024 for the orthogonal frequency division multiplexing (OFDM) scheme in 3rd generation partnership program (3GPP)-long term evolution (LTE) and LTE-Advanced (LTE-A). This paper aims to optimize the FFT sizes with respect to quadrature phase shift keying (QPSK), 16, 64 and 256-quadrature amplitude...
This paper experimentally investigates and compares the performance of the free space optics system employing three different modulation schemes, on-off keying (OOK) with non-return-to-zero (NRZ) and return-to-zero (RZ) and the binary phase shift keying (BPSK) operating under the turbulent atmosphere. The received average signal is measured and used to characterize the strength of the turbulence....
Free-space optical communications (FSO) propagated over a clear atmosphere suffers from irradiance fluctuation caused by small but random atmospheric temperature fluctuations. This results in decreased signal-to-noise ratio (SNR) and consequently impaired performance. In this paper, the error performance of the FSO using a subcarrier intensity modulation (SIM) based on a binary phase shift keying...
Visible light LEDs are being used for indoor optical wireless systems as well as room lighting. In indoor diffuse optical wireless links multipath dispersion limits the maximum transmission data rates. In this paper we investigate OFDM system where multipath induced intersymbol interference (ISI) is reduced, enabling higher data rates. Pilot signals are uniformly inserted into data symbols (subcarriers)...
Free-space optical communications (FSO) propagated over a clear atmosphere suffers from irradiance fluctuation caused by small but random atmospheric temperature fluctuations. This results in decreased signal- to-noise ratio and consequently impaired error performance. In this paper, the error performance of the FSO using a subcarrier intensity modulation (SIM) based on a binary phase shift keying...
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