215 research outputs found

    Wideband channel modeling for mm-wave inside trains for 5G-related applications

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    Passenger trains and especially metro trains have been identified as one of the key scenarios for 5G deployments. The wireless channel inside a train car is reported in the frequency range between 26.5GHz and 40GHz. These bands have received a lot of interest for high-density scenarios with a high-traffic demand, two of the most relevant aspects of a 5G network. In this paper we provide a full description of the wideband channel estimating Power-Delay Profiles (PDP), Saleh-Valenzuela model parameters, time-of-arrival (TOA) ranging, and path-loss results.Moreover, the performance of an automatic clustering algorithm is evaluated. The results show a remarkable degree of coherence and general conclusions are obtained.Enabling 5G TEC2014-55735-C3-2-R is funded by the Spanish Ministry of Economy and Competitiveness and also is funded by the Chinese Strategic International Cooperative Project of National key R&D Plan, 2016YFE0200200

    Millimeter Wave Channel Measurements in an Intra-Wagon Environment

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    © 2019 IEEE. Personal use of this material is permitted. Permissíon from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertisíng or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works."[EN] In this correspondence, useful measurement results of the propagation channel characteristics in an intra-wagon environment at millimeter wave (mmWave) frequencies are presented. The measurements were collected inside an underground convoy from 25 to 40 GHz in the frequency domain. A broadband radio over fiber (RoF) link was used in order to avoid the high losses introduced by cables at these frequencies, thus allowing long distances between the transmitter and receiver antennas. Values of the path loss exponent and delay spread are reported at the potential 26, 28 and 38 GHz bands to deploy the future fifth-generation (5G) systems. These results allow us to have a better knowledge of the path loss and time dispersion characteristics of the propagation channel in this particular environment, characterized by rich-scattering with long delays.This work was supported by the Ministerio de Economia, Industria y Competitividad of the Spanish Government under the National Projects TEC2016-78028-C3-2-P and TEC2017-86779-C2-2-R, through the Agencia Estatal de Investigacion (AEI) and the Fondo Europeo deDesarrollo Regional (FEDER). The review of this article was coordinated by Prof. J. F. Paris. The authors would like to thank the staff of FGV who have facilitated the realization of the measurements campaing, in particular J. Iserte Villalba and F. M. Brox López.Rubio Arjona, L.; Rodrigo Peñarrocha, VM.; Molina-García-Pardo, JM.; Juan Llacer, L.; Pascual Garcia, J.; Reig, J.; Sanchis Borrás, C. (2019). Millimeter Wave Channel Measurements in an Intra-Wagon Environment. IEEE Transactions on Vehicular Technology. 68(12):12427-12431. https://doi.org/10.1109/TVT.2019.2947205S1242712431681

    6G Enabled Advanced Transportation Systems

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    The 6th generation (6G) wireless communication network is envisaged to be able to change our lives drastically, including transportation. In this paper, two ways of interactions between 6G communication networks and transportation are introduced. With the new usage scenarios and capabilities 6G is going to support, passengers on all sorts of transportation systems will be able to get data more easily, even in the most remote areas on the planet. The quality of communication will also be improved significantly, thanks to the advanced capabilities of 6G. On top of providing seamless and ubiquitous connectivity to all forms of transportation, 6G will also transform the transportation systems to make them more intelligent, more efficient, and safer. Based on the latest research and standardization progresses, technical analysis on how 6G can empower advanced transportation systems are provided, as well as challenges and insights for a possible road ahead.Comment: Submitted to an open access journa

    Performance analysis of massive multiple input multiple output for high speed railway

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    This paper analytically reviews the performance of massive multiple input multiple output (MIMO) system for communication in highly mobility scenarios like high speed Railways. As popularity of high speed train increasing day by day, high data rate wireless communication system for high speed train is extremely required. 5G wireless communication systems must be designed to meet the requirement of high speed broadband services at speed of around 500 km/h, which is the expected speed achievable by HSR systems, at a data rate of 180 Mbps or higher. Significant challenges of high mobility communications are fast time-varying fading, channel estimation errors, doppler diversity, carrier frequency offset, inter carrier interference, high penetration loss and fast and frequent handovers. Therefore, crucial requirement to design high mobility communication channel models or systems prevails. Recently, massive MIMO techniques have been proposed to significantly improve the performance of wireless networks for upcoming 5G technology. Massive MIMO provide high throughput and high energy efficiency in wireless communication channel. In this paper, key findings, challenges and requirements to provide high speed wireless communication onboard the high speed train is pointed out after thorough literature review. In last, future research scope to bridge the research gap by designing efficient channel model by using massive MIMO and other optimization method is mentioned

    Millimeter Wave MISO-OFDM Transmissions in an Intra-Wagon Environment

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    [EN] In this paper, the maximum achievable throughput is analyzed in the intra-wagon channel when multiple-input single-output (MISO) and orthogonal frequency division multiplexing (OFDM), MISO-OFDM, techniques are used. This analysis is performed from real wideband propagation channel measurements at 28 and 37 GHz, two potential frequency bands to deploy the future fifth-generation (5G) wireless communications networks. Four different scenarios in terms of the access point (AP) and user equipment (UE) positions inside the wagon have been considered, using 4 and 8 antennas at the AP. The performance of both quasi-orthogonal space-time block code (QSTBC), combined with Hadamard matrices, and transmit beamforming techniques is studied and evaluated from simulation results. The simulation results take into account the signal-to-noise ratio (SNR) and the antenna correlation for each antenna array configuration at the AP. These results provide useful insight to better understand the intra-wagon channel properties and deploy the future 5G wireless networks in this particular scenario at mmWave frequencies, where high-data-rates are expected to support different types of digital applications.This work was supported in part by the Ministerio de Economia y Competitividad MINECO, Spain, under Grant TEC2016-78028C3-2-P and Grant TEC2017-86779-C2-2-R and in part by the European FEDER Funds.Sanchis Borrás, C.; Molina-García-Pardo, J.; Rubio Arjona, L.; Pascual-García, J.; Rodrigo Peñarrocha, VM.; Juan Llacer, L.; Reig, J. (2021). Millimeter Wave MISO-OFDM Transmissions in an Intra-Wagon Environment. IEEE Transactions on Intelligent Transportation Systems. 22(8):4899-4908. https://doi.org/10.1109/TITS.2020.2983028S4899490822

    1-D broadside-radiating leaky-wave antenna based on a numerically synthesized impedance surface

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    A newly-developed deterministic numerical technique for the automated design of metasurface antennas is applied here for the first time to the design of a 1-D printed Leaky-Wave Antenna (LWA) for broadside radiation. The surface impedance synthesis process does not require any a priori knowledge on the impedance pattern, and starts from a mask constraint on the desired far-field and practical bounds on the unit cell impedance values. The designed reactance surface for broadside radiation exhibits a non conventional patterning; this highlights the merit of using an automated design process for a design well known to be challenging for analytical methods. The antenna is physically implemented with an array of metal strips with varying gap widths and simulation results show very good agreement with the predicted performance

    Beam scanning by liquid-crystal biasing in a modified SIW structure

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    A fixed-frequency beam-scanning 1D antenna based on Liquid Crystals (LCs) is designed for application in 2D scanning with lateral alignment. The 2D array environment imposes full decoupling of adjacent 1D antennas, which often conflicts with the LC requirement of DC biasing: the proposed design accommodates both. The LC medium is placed inside a Substrate Integrated Waveguide (SIW) modified to work as a Groove Gap Waveguide, with radiating slots etched on the upper broad wall, that radiates as a Leaky-Wave Antenna (LWA). This allows effective application of the DC bias voltage needed for tuning the LCs. At the same time, the RF field remains laterally confined, enabling the possibility to lay several antennas in parallel and achieve 2D beam scanning. The design is validated by simulation employing the actual properties of a commercial LC medium

    Analysis of wideband phased array beamforming at millimeter wave frequencies

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    Abstract. Industries are undergoing an information and communication technology-driven transformation as the world becomes increasingly digitally and globally linked. 5G technology provides a common basis for providing the multiple vertical sectors with a more cost-effective, open, and wide ecosystem solutions. Due to the generally large attainable bandwidths, high frequency technologies have emerged as a promising solution for future wireless communications and attracted great interest in the literature. The millimeter wave (mmWave), i.e., the frequency range 30–300 GHz, would enable the exploitation of tens of gigahertz transmission bands, resulting in a massive channel capacities of even over one Tbps. However, one of the most challenging issues in high-frequency communication connections is the significant channel losses that require highly directional antennas and, in most cases, line-of-sight link between the transmitter and receiver. In this thesis, we study the beamforming design for wideband systems with different bandwidths. The simulation results show that with a larger bandwidth, the power loss increases with the beamforming angle. The loss of power behavior due to beam squinting effect is quite similar over different distances

    Antennas and Propagation Aspects for Emerging Wireless Communication Technologies

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    The increasing demand for high data rate applications and the delivery of zero-latency multimedia content drives technological evolutions towards the design and implementation of next-generation broadband wireless networks. In this context, various novel technologies have been introduced, such as millimeter wave (mmWave) transmission, massive multiple input multiple output (MIMO) systems, and non-orthogonal multiple access (NOMA) schemes in order to support the vision of fifth generation (5G) wireless cellular networks. The introduction of these technologies, however, is inextricably connected with a holistic redesign of the current transceiver structures, as well as the network architecture reconfiguration. To this end, ultra-dense network deployment along with distributed massive MIMO technologies and intermediate relay nodes have been proposed, among others, in order to ensure an improved quality of services to all mobile users. In the same framework, the design and evaluation of novel antenna configurations able to support wideband applications is of utmost importance for 5G context support. Furthermore, in order to design reliable 5G systems, the channel characterization in these frequencies and in the complex propagation environments cannot be ignored because it plays a significant role. In this Special Issue, fourteen papers are published, covering various aspects of novel antenna designs for broadband applications, propagation models at mmWave bands, the deployment of NOMA techniques, radio network planning for 5G networks, and multi-beam antenna technologies for 5G wireless communications
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