The filter bank multicarrier (FBMC) modulation format is considered as a potential candidate for future wireless 5G due to its feature of high suppression for out-of-band emissions, which allows combining multiple sub-bands with very narrow band-gaps, and hence increases the overall wireless transmission capacity. In this paper, we experimentally demonstrate the generation of multi sub-bands FBMC signals at millimeter-wave (mm-wave) for radio-over-fiber (RoF) systems. The designed multi sub-bands FBMC system consists of 5 sub-bands of 800 MHz with inter sub-band gaps of 781.25 kHz. The composite 5 sub-bands FBMC signal is generated with no band-gap between dc to the first sub-band to preserve the bandwidth of the system. Each FBMC sub-band consists of 1024 sub-carriers and is modulated with uncorrelated data sequences. The aggregate FBMC signal is carried optically by externally modulating a free running laser and is converted to millimeter waves (mm-waves) by photomixing with another free running laser at a frequency offset of 53 GHz. At the receiver, the received electrical mm-wave signal is down-converted to an intermediate frequency (IF) and then post-processed using digital signal processing (DSP) techniques. With the use of the simple recursive least square (RLS) equalizer in the DSP receiver, the achieved aggregate data rate is 8 Gbps and 12 Gbps for 16 quadrature amplitude modulation (QAM), and 64 QAM, respectively with a total bandwidth of 4.2 GHz. The system performance is evaluated by measuring error vector magnitude (EVM) and bit error rate (BER) calculations.
Communication applying visible light technology is a novel approach. Visible Light Communication (VLC) development is motivated by the increasing demand for wireless communication technologies. It has the potential to provide highspeed data communication with good security and improved energy efficiency. The rapid evolution of VLC was sustained by the LEDs performances. The Light-Emitting-Diode (LED) luminaires are capable of switching to the different light intensity at a fast rate. This function can be used for data transmission. This article focuses on the physical layer of the VLC links. It reviews the technology, the topology of the proposed connection, and the benefits of this approach. The main research trends are identified emphasizing state of the art in this area. It shows how VLC technology evolved and what are the performances achieved at this time. Various structures of the transmitter and receiver are studied, and different modulation schemes are investigated. Finally, numerous applications of VLC technology are presented.
Abstract-This paper demonstrates a hybrid radio over multimode fibre and free space optics (RoMMF-FSO) system that can be used to extend the transmission range of the 4 th generation longterm evolution (4G-LTE) signal in access networks. A single mode filtering technique (SMFT) is used to enhance 4G-LTE performance. The proposed scheme is evaluated in terms of the system transfer function, laser beam profile, and error vector magnitude (EVM). We show that using SMFT increases the RoMMF-FSO system bandwidth by 2 GHz and improves the received optical power by 13.6 dB. Moreover, the proposed system enhances the EVM by 4%. The measured results show that using a 1 km MMF instead of a 1 km SMF will marginally increase the measured EVM from ~6.6% to ~7% with a 0.2 dB power penalty with respect to the LTE EVM limit of 12.5% as is specified for 16-quadrature amplitude modulation. The proposed system is validated practically under atmospheric turbulence conditions to mimic the outdoor environment. Measured EVM results are verified theoretically through transmitting LTE signals with turbulent using log-normal model. We also show that for a FSO link span of 500 m to meet the EVM target of 12.5% the SNR power penalties are ~2 dB and ~11 dB for σ R 2 of 1.2×10 -4 and 0.1, respectively compared with no turbulence.Index Terms-Free space optics, long term evolution, multimode optical fibres, radio-over-fibre.
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