Répéteur

Résumé

thumb|Un répéteur sans-fil Un répéteur désigne un couple de fréquences modulées ou un équipement électronique combinant un récepteur et un émetteur; ce dispositif est notamment censé compenser les pertes de transmission d'un média (ligne, fibre, radio, télédiffusion, en traitant et en amplifiant éventuellement le signal, sans en modifier le contenu, ni les données. Dans le domaine de la télédiffusion ou des télécommunications, un répéteur ou en anglais transponder, désigne un canal de modulation exploité dans les transmissions radio, de télévision et de données numériques qui véhicule des signaux exploités dans d'autres fréquences d'émission. Ainsi, pour la télédiffusion par satellite, le signal de montée ou en anglais « uplink » exploite une fréquence différente du signal de réception ou en anglais, « downlink ». Répéteur dans un réseau télécommunications numériques Le répéteur, encore appelé répéteur-régénérateur est un équipement électronique servant à dupliquer et à

Source officielle

https://fr.wikipedia.org/wiki/R%C3%A9p%C3%A9teur

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Mobile network operators constantly have to upgrade their cellular network to satisfy the public's hunger for increasing data capacity. However, regulatory limits regarding allowed electromagnetic field strength on existing cell sites often limit or prevent the installation of new cells on additional frequency bands. Further densifying the radio access infrastructure by means of new cell sites takes time because of the site acquisition, the need for permissions, and the civil construction. To this end, amplify-and-forward repeaters are a cost-efficient method to provide mobile wireless data capacity to concealed areas outdoors, inside buildings, or vehicles, where low signal levels drastically limit the achievable capacity or even prevent communication with distant base stations. Repeaters with high-gain beamforming antennas can be used to decrease the path loss and thereby offer a higher capacity than user equipment otherwise could achieve. Since those highly directional beams must be constantly adjusted, we propose methods to align and track the beam even without having access to in-band beam control mechanisms. Numerical analyses with measurement data show that such non-invasive (system data-agnostic) methods are feasible and only incur a few percent in throughput reduction.

IEEE2022

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Increasing Cellular Network Energy Efficiency for Railway Corridors

Andreas Peter Burg, Ruben Merz, Adrian Schumacher

Modern trains act as Faraday cages making it challenging to provide high cellular data capacities to passengers. A solution is the deployment of linear cells along railway tracks, forming a cellular corridor. To provide a sufficiently high data capacity, many cell sites need to be installed at regular distances. However, such cellular corridors with high power sites in short distance intervals are not sustainable due to the infrastructure power consumption. To render railway connectivity more sustainable, we propose to deploy fewer high-power radio units with intermediate low-power support repeater nodes. We show that these repeaters consume only 5% of the energy of a regular cell site and help to maintain the same data capacity in the trains. In a further step, we introduce a sleep mode for the repeater nodes that enables autonomous solar powering and even eases installation because no cables to the relays are needed.

IEEE2022

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Reconfigurable Pixel-Layer Isolator for Frequency-Tunable On-Frequency Repeaters

Daniel Rodrigo Lopez

The maximum gain in on-frequency repeaters is limited by the isolation level between their two antennas due to close-loop stability conditions. In this letter, a novel pixel-layer isolator for tunable on-frequency repeaters is presented. The scattered field of the reconfigurable pixel layer is used to dynamically minimize the mutual coupling between the antennas. Insight is given on the linkage between coupling and reflection coefficients, and a useful design procedure is proposed. The optimized pixel repeater can tune the operating frequency over a 40% range, with tunable instantaneous bandwidth (1%-3%) and achieving a reliable isolation of 50 dB. The repeater has a radiation efficiency of 93% and a constant radiation pattern for the different configurations. Good agreement is obtained between simulations and measurements.

Institute of Electrical and Electronics Engineers2014

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