Process for synchronization of communication involving multiple user equipments with a head-end equipment by means of OFDM modulation in the upstream channel

Where synchronization in time and frequency in the downstream channel has been previously carried out, and determined by the sending of synchronization sequences (3) in a communication between a head-end (1) and user equipment (2); the present invention is characterized because it corrects sampling...

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Bibliographische Detailangaben
Hauptverfasser:	GAVILLERO MARTIN JUAN MIGUEL, IRANZO MOLINERO SALVADOR, RIVEIRO INSUA JUAN CARLOS, BLASCO CLARET JORGE VICENTE
Format:	Patent
Sprache:	eng
Schlagworte:	BLASTING CHEMICAL SURFACE TREATMENT CHEMISTRY COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATIONOR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY IONIMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL COATING MATERIAL WITH METALLIC MATERIAL COATING METALLIC MATERIAL COMBUSTION ENGINES DIFFUSION TREATMENT OF METALLIC MATERIAL ELECTRIC COMMUNICATION TECHNIQUE ELECTRICITY HEATING HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION INGENERAL JET-PROPULSION PLANTS LIGHTING MECHANICAL ENGINEERING METALLURGY SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THESURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHICCOMMUNICATION WEAPONS
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Beschreibung
Zusammenfassung:	Where synchronization in time and frequency in the downstream channel has been previously carried out, and determined by the sending of synchronization sequences (3) in a communication between a head-end (1) and user equipment (2); the present invention is characterized because it corrects sampling frequency in the user equipments (2) by starting from the estimation carried out during frequency synchronization in the downstream channel, to synchronize the upstream channel in frequency, removing the need for the head-end to make corrections in reception in the upstream channel. The user equipment (2) estimates (9) the moment the OFDM symbols (7) should be sent to the head-end (1) so that these are received by it at previously fixed moments in time. Furthermore, this invention includes interrogation of the user equipment (2), which allows them to place requests for access to the upstream channel with the head-end then making the distribution between the requests received. It is applicable to sending of data in bi-directional communication over the electric network.