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Channel modeling and analysis of OWC-massive MIMO systems
摘要： In this paper, we study the difference between the uplink and downlink channels of short-range slant free-space optical wireless between Ground - alpine base stations using massive MIMO linear arrays at both ends. The uplink and downlink atmospheric loss, scintillation, beam spreading and pointing error model of linear array slant range are constructed. The uplink and downlink atmospheric loss, spatial coherence length, receiver beamwidth, pointing error variance, relative mean square error (RMSE) and bit error rate (BER) are compared and analyzed under different distances of different wavelengths of light waves. After simulation analysis, it is concluded that the uplink and downlink atmospheric losses are the same, the uplink receiver beamwidth is larger than the downlink, and the downlink coherence length and the pointing error variance are larger than the uplink, and both monotonously change with the wavelength of the light wave and the propagation distance.
关键词： Optical wireless communication,MSE,Wavelength,Channel modeling,Massive MIMO
更新于2025-09-23 15:23:52
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[IEEE 2018 43rd International Conference on Infrared, Millimeter, and Terahertz Waves (IRMMW-THz2018) - Nagoya, Japan (2018.9.9-2018.9.14)] 2018 43rd International Conference on Infrared, Millimeter, and Terahertz Waves (IRMMW-THz) - Turning THz Communications into Reality: Status on Technology, Standardization and Regulation
摘要： Already a couple of years ago THz communications have not only become an attractive new research area on channel modeling but also triggered a couple of projects heading to develop appropriate technological solutions to enable the set-up of hardware demonstrators. Also discussions and activities in standardization and regulation already took off. In October 2017, IEEE published Std. IEEE 802.15.3d-2017 the worldwide first wireless communications standard operating in the 300 GHz frequency band. In parallel to the standardization process activities at the ITU-R level targeting on the provision of an appropriate regulatory framework at the World Radio Conference 2019 (WRC-2019) via a dedicated agenda item have taken off. This paper provides a brief overview on the current status of the development of THz Communication systems focusing on recent results on advanced channel characterization at 300 GHz, hardware demonstrators operating in this frequency range, the past and current activities at IEEE 802 and the WRC 2019 preparations.
关键词： channel modeling,standardization,THz communications,regulation,hardware demonstrators
更新于2025-09-23 15:21:01
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Wireless Energy Transmission Channel Modeling in Resonant Beam Charging for IoT Devices
摘要： Power supply for Internet of Things (IoT) devices is one of the bottlenecks in IoT development. To provide perpetual power supply for IoT devices, resonant beam charging (RBC) is a promising safe, long-range and high-power wireless power transfer solution. How long distance RBC can reach and how much power RBC can transfer? In this paper, we analyze the consistent and steady operational conditions of the RBC system, which determine the maximum power transmission distance. Then, we study the power transmission efficiency within the operational distance, which determines the deliverable power through the RBC energy transmission channel. Based on the theoretical model of the wireless energy transmission channel, we establish a testbed. According to the experimental measurement, we validate our theoretical model. The experiments verify that the output electrical power at the RBC receiver can be up to 2W. The maximum energy transmission distance is 2.6m. Both the experimental and theoretical performance of the RBC system are evaluated in terms of the transmission distance, the transmission efficiency, and the output electrical power. Our theoretical model and experimental testbed lead to the guidelines for the RBC system design and implementation in practice.
关键词： Wireless Power Transfer,Energy Transmission Channel Modeling,Experimental Testbed,Resonant Beam Charging
更新于2025-09-19 17:15:36
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Performance enhancement of high-capacity coherent DWDM free-space optical communication link using digital signal processing
摘要： In this paper, 1.28 Tbps (32 × 40 Gbps) high-capacity DWDM-FSO link has been investigated for performance enhancement using coherent detection and digital signal processing (DSP). The DP-16QAM-modulated proposed DWDM-FSO link has been analyzed for both adverse weather and turbulent atmospheric conditions. It is observed that when link is subjected to strong turbulence along with adverse weather conditions, the DSP-aided coherent DWDM-FSO receiver achieves target bit error rate (BER) of 10?4 at signal-to-noise ratio (SNR) of 36.4 dB, while for similar conditions, the SNR requirements for IM/DD-based DWDM-FSO link shoots by 12.8 dB to 49.2 dB. Also, in terms of operational link range, the proposed link even under strong turbulent conditions serves 1.88 km, whereas IM/DD link was restricted to mere 1.12 km for target of BER of 10?4, thus producing a decent range increment of 760 m. The proposed link has been designed and investigated using OptiSystem? 14.2.
关键词： Atmospheric turbulence,Coherent detection,Digital signal processing,Free-space optical communication,Gamma–Gamma channel modeling,DWDM
更新于2025-09-16 10:30:52
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A Proposal to Improve Ray Launching Techniques
摘要： In this study, we demonstrate the implementation of an algorithm to model 3D-ray launching. A fixed-size reception sphere and cylinder is used in conjunction with numerical methods to simulate the multipath propagation in a reduced computational time while retaining accuracy. This approach was implemented in a two office environments that were validated previously by the authors in different simulations. The mathematical feasibility of this method in these applications is demonstrated and the obtained results are discussed. The proposed method has been previously validated by authors in different simulations shown in references.
关键词： Propagation,Ray Tracing,Channel modeling,Ray Launching
更新于2025-09-10 09:29:36
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Visible Light Communications (Theory and Applications) || Lighting and Communications: Devices and Systems
摘要： An important step in the design of a visible light communications (VLC) system is to comprehend the limitations arising from the optical wireless channel. Accurate channel characterization is an important prerequisite to set the system parameters appropriately in order to establish a high-quality link since it permits better exploitation of the available energy and spectral resources in view of optimizing the system design. An accurate channel model is also necessary to precisely predict the performance of VLC systems. In this chapter, we address channel modeling for VLC systems mainly focusing on indoor systems. We introduce different sources of impairment in VLC systems arising from beam propagation or transmitter (Tx)/receiver (Rx) devices. Indeed, the latter could be attributed to the “global channel” comprising the blocks between the signal Tx and signal detection at the Rx. After this introduction, we give an overview of different propagation modes in Section 3.2. In addition, we explain methods for numerical channel simulation. Analytical channel modeling for the cases of single- and multiple-source systems is presented in Section 3.3. Then, in Section 3.4, we outline the limitations arising from the aggregate channel while focusing on the problem of intersymbol interference (ISI) and how it affects the link performance particularly in the absence of a line of sight (LOS). This could be due to multipath-induced channel time dispersion, that is, multiple reflections from people and objects within an indoor environment, the lack of sufficient bandwidth of the transmitting device, most commonly a light-emitting diode (LED), the photodetector (PD), and the cabling used for lighting installations. Limitations due to the LED nonlinear characteristics could also be considered as an impairment of the global channel, which is the subject of Section 3.5 where channel distortion modeling is investigated. Finally, channel modeling for multiple-input multiple-output (MIMO) VLC systems will be presented next in Section 3.6.
关键词： Channel Modeling,Intersymbol Interference,Multiple-Input Multiple-Output,Optical Wireless Channel,Visible Light Communications
更新于2025-09-09 09:28:46
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Millimeter-Wave Channel Measurement and Modeling: A NIST Perspective
摘要： The exponential increase in wireless data transmission from smartphones has led to the saturation of the sub-6-GHz bands — where cellular networks have operated to date — forcing providers to migrate to the millimeter-wave (mmWave) regime for 5G. Although available channel bandwidths will grow from tens of megahertz to several gigahertz, propagation loss will be substantially higher. To compensate the link budget, phased array antennas with 20 dBi–40-dBi gain will be employed at the base and mobile stations. Since beamwidth is inversely proportional to gain, the resultant pencilbeams will be only 3°–15° wide and thus must be electronically steered to ensure that they are aligned between the stations. The high directionality of 5G systems will fundamentally change channel propagation models and channel sounding systems and techniques used to measure the model properties. The National Institute of Standards and Technology is on the forefront of defining that change. In this article, we provide an overview of mmWave channel sounding through three types of systems: switched array, virtual array, and phased array, at 28 GHz, 60 GHz, and 83 GHz. In addition, we describe how mmWave channel models, for path loss, dispersion, multipath tracking, Doppler spread, and blockage, differ from sub-6-GHz models, substantiated by some of our most recent results.
关键词： Doppler spread,path loss,millimeter-wave,dispersion,5G,multipath tracking,blockage,channel sounding,channel modeling
更新于2025-09-09 09:28:46
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[Institution of Engineering and Technology 12th European Conference on Antennas and Propagation (EuCAP 2018) - London, UK (9-13 April 2018)] 12th European Conference on Antennas and Propagation (EuCAP 2018) - Path loss model modification for various gains and directions of antennas
摘要： Emerging telecommunication technologies like 5G, green communications, and massive MIMO contribute to the use of directional antennas and beamforming. For this reason, modern propagation models consider directional antennas with different beam widths, gains and radiation pattern directions. Most of the available propagation models are based on omnidirectional or isotropic antennas. A proposition to solve this problem is an empirical path loss model that considers the different types of antennas. This model assumes that the transmitting and receiving antenna beams are directing each other. In this paper, we propose modifying this model by determining attenuation for any direction of the antenna patterns. For this aim, the multi-elliptic channel model is used.
关键词： gain,non-line-of-sight conditions,directional antenna,multipath propagation,multi-elliptical channel model,antenna pattern,channel modeling,path loss model
更新于2025-09-04 15:30:14