Method and arrangement to synchronize a multi-carrier transmission system
AssigneeAlcatel
InventorsPhilippe Antoine, Wim Andre Paula De Wilde
Life of this patent
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Abstract
The invention relates to a method to synchronise a multi-carrier transmission system wherein a time misalignment between a transmitter and a receiver is determined through an average of at least two pilot tones phase errors (Øi) weighted in accordance with the noise affecting each pilot tone transmission. Such method is characterised in that, when the noise affecting a pilot tone (38, 40) reaches a predetermined level, the pilot tone function is reallocated from this pilot tone (38, 40) to another carrier (42, 44) and/or this pilot tone weight is reduced.
Claims16
A method to synchronise a multi-carrier transmission system wherein a time misalignment (Δt) between a transmitter and a receiver is determined through an average of at least two pilot tones phase errors (Øi) weighted (Ai) in accordance with the noise (Ni) affecting each pilot tone transmission, characterised in that, when the noise (Ni) affecting a pilot tone (38, 40) reaches a predetermined level, the pilot tone function is reallocated from this pilot tone (38, 40) to another carrier (42, 44) and/or this pilot tone weight (Ai) is reduced.
A method according to any of the previous claims characterised in that, for determining the noise affecting each carrier, the signal to noise ratio value of each carrier is determined.
A method according to any of the previous claims characterised in that, for determining the noise affecting each carrier, a phase angle dispersion is determined.
A method according to any of the previous claims characterised in that the communications system is an Asymmetric Digital Subscriber Line (ADSL) system, wherein data is modulated on sets of carriers and constitutes Discrete Multi Tone (DMT) symbols.
An arrangement to determine, in a multi-carrier system, a time misalignment (Δt) between a transmitter clock and a receiver clock through an average of at least two pilot tones phase errors (Øi) weighted (Ai) in accordance with the noise (Ni) affecting each pilot tone transmission, characterised in that it comprises means for allocating the pilot tone function of a pilot tone (38, 40) to another carrier (42, 44) and/or to reduce the weight (Ai) of a pilot tone (38, 40) when the noise (Ni) affecting such pilot tone (38, 40) reaches a predetermined level.
Dependencies are inferred from the claim text.