3,924 research outputs found

    Maximising the system spectral efficiency in a decentralised 2-link wireless network

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    <p>Abstract</p> <p>This paper analyses the system spectral efficiency of a 2-link wireless network. The analysis reveals that there exist three operating points that possibly maximise the system spectral efficiency: either both links transmit with maximum power simultaneously or one single link transmits with maximum power while the other is silent. The impact of the chosen multiple access scheme on the system spectral efficiency is also studied: simultaneous transmission or sequential access where the two links share the medium by dedicated time/frequency slots without causing interference. An exhaustive numerical search over a wide range of channel realisations quantifies the gains in system spectral efficiency when choosing either the optimal, single, simultaneous, or sequential medium access. Furthermore, issues regarding the power efficiency are addressed. Finally, the restriction to a 2-link network is relaxed by introducing background interferers, reflecting a multiple link scenario with one dominant interferer. Simulation results indicate that increasing background interference reduces the advantage of sequential over simultaneous transmission.</p

    Cognitive node selection and assignment algorithms for weighted cooperative sensing in radar systems

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    Proceedings of the Second International Mobile Satellite Conference (IMSC 1990)

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    Presented here are the proceedings of the Second International Mobile Satellite Conference (IMSC), held June 17-20, 1990 in Ottawa, Canada. Topics covered include future mobile satellite communications concepts, aeronautical applications, modulation and coding, propagation and experimental systems, mobile terminal equipment, network architecture and control, regulatory and policy considerations, vehicle antennas, and speech compression

    Multi-antenna 3D pattern design for millimeter-wave vehicular communications

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    The transformation of the automotive industry towards ubiquitous connection of vehicles with all kind of external agents (V2X) motivates the use of a wide range of frequencies for several applications. Millimeter-wave (mmWave) connectivity represents a paramount research field in which adequate geometries of antenna arrays must be provided to be integrated in modern vehicles, so 5G-V2X can be fully exploited in the Frequency Range 2 (FR2) band. This paper presents an approach to design mmWave vehicular multi-antenna systems with beamforming capabilities considering the practical limitations of their usage in real vehicular environments. The study considers both the influence of the vehicle itself at radiation pattern level and the impact of the urban traffic on physical layer parameters. Connectivity parameters such as Signal-to-Interference-plus-Noise Ratio (SINR) and outage probability are optimized based on the array topology. A shaped beam in the vertical plane based on three preset radiating elements is proven to be robust enough against self-scattering effects on the vehicle body. Regarding the horizontal geometry, four panels on the roof's edges provide good coverage and link quality. The number of horizontal antennas per panel tightly depends on the required values of the link quality metrics, potentially leading to a non-uniform geometry between sides and front or back panels.This work was partly funded by the Spanish Ministerio de Economía y Competitividad under the projects PID2019-107885GB- C31 and MDM2016-0600, the Catalan Research Group 2017 SGR 219, and “Industrial Doctorate” programme (2018-DI-084). The Spanish Ministry of Education contributes via a predoctoral grant to the first author (FPU17/05561).Peer ReviewedPostprint (published version
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