Orange

France Telecom

Fabienne Moulin

Alain Cario

Rabah Tarafi

Mohamed Tlich

Eric Debeau

Ahmed Zeddam

Bastien Lamer

A method of estimating a noise present on a 2-wire line connected to a modem using a plurality of frequency bands is implemented by a noise estimation device connected to the 2-wire line. The method comprises obtaining a first voltage value of a differential mode voltage at the two wires of the secondary side of the differential mode circuit, the first voltage value measured on the plurality of frequency bands and a second voltage value of a common mode image voltage corresponding to a voltage at the two wires of the secondary side of the common mode circuit, resulting from said differential mode voltage, the second voltage value being measured on the plurality of frequency bands and transmitting the first voltage value and the second voltage value to a calculating module configured to provide a noise estimate based on the first and second voltage values.

Method and device for cancelling noise for 2-wire transmission systems

A method of cancelling noise present in a data signal received on an electrical bifilar line, is implemented by a sender-receiver device comprising a first transformer, termed the differential mode circuit, the primary side of the first transformer connected by two wires to the bifilar line, a second transformer, termed the common mode circuit, the primary side of the second transformer connected to the primary side of the differential mode circuit, and to ground. The method comprises during an adjustment phase: obtaining a first voltage value on the bifilar line, termed the differential mode voltage; obtaining a second voltage value at the common mode circuit, termed the image voltage, resulting from the differential mode voltage; calculating the ratio between the second and first voltage values, termed the conversion ratio. The method comprising during a cancellation phase, subsequent to the adjustment phase; receiving the data signal and simultaneously obtaining a third value corresponding to the image voltage; cancelling the noise in the data signal, by subtracting an estimation of the noise, calculated by dividing the third value by the conversion ratio.

The invention relates in particular to a method of adjusting power spectral densities of a plurality of telecommunications lines sending data in a plurality of frequency sub-bands, a power spectral density being assigned to each sub band sending data. The method comprises the following steps: selecting at least one line, called the donor line, whose capacity for sending data is higher than a predetermined reference capacity, selecting at least one sub band of said donor line, and reducing the power spectral density assigned to the selected sub band to a predefined minimum power level in said sub band.

Device and a method for adjusting power spectral densities of a plurality of telecommunications lines

A method of allocating a plurality of subbands to a plurality of streams of a multichannel link in a multicarrier modulation communications system, each stream being successively defined in a communications frame of said multichannel link by a number Mof bits to be transmitted and a noise margin &#x393;. Each subband is associated with a normalized signal-to-noise ratio on the multichannel link. The subbands are classified in a specific order of the normalized signal-to-noise ratios. An energy Eper subband is determined by a binary allocation algorithm. For each stream taken in the order of said frame, a number Nof consecutive subbands taken in the order of normalized signal-to-noise ratios is allocated so that the sum of the numbers nof bits in each subband allocated to each stream is equal to Mwhere: and n=log(1+E&#xb7;(SNR)/&#x393;).

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Trevou Treguignec, France

Fabienne Moulin