Ingress noise reduction in a digital receiver
AssigneeJuniper Networks, Inc.
InventorsAmbroise Popper, Fabien Buda, Hikmet Sari
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Abstract
The invention provides a device (D2) for reducing ingress noise in a digital signal, comprising a noise predictor (20) for predicting an amount of ingress noise in the digital signal (sn) based on past samples of the ingress noise, and a subtractor (21) for subtracting the predicted amount of ingress noise from the digital signal. Channel distortion is compensated for by a noise-independent equalizer (25), such as a ZF equalizer, placed upstream of the noise predictor (20). The device (D2) may be incorporated, for example, in a cable modem termination system (CMTS) of an hybrid fiber/coax (HFC) network.
Claims25
A device for reducing ingress noise in a digital signal, characterized in that it comprises:
- noise predicting means for predicting an amount of ingress noise in the digital signal, and
- first subtracting means for subtracting the predicted amount of ingress noise from the digital signal.
A communication system for use as a termination system for a plurality of transmitters in a TDMA network, said communication system comprising:
- a modulator;
- a demodulator including a linear noise predicting filter;
- and
- a control unit,
- wherein the demodulator reduces ingress noise in a digital signal received from at least one of said transmitters and
- the control unit is arranged to control the demodulator so that the coefficients of the linear noise predicting filter in the demodulator are adapted at least during reserved time slots in which no transmitter is allowed to transmit towards the communication system.
A communication system for use as a termination system for a plurality of transmitters in a TDMA network, said communication system comprising:
- a modulator;
- a demodulator including a linear noise predicting filter;
- and
- a control unit,
- wherein the demodulator reduces ingress noise in a digital signal received from at least one of said transmitters and
- the control unit is arranged to control the demodulator so that coefficients of the linear noise predicting filter in the demodulator are adapted at least during reserved time slots in which no transmitter is allowed to transmit towards the communication system and to control the demodulator so that said demodulator outputs decision symbols (dn) which are systematically equal to zero during the reserved time slots.
A cable modem termination system for a hybrid fiber/coax network, comprising
- a modulator;
- a demodulator;
- and
- a control unit connected to the modulator and the demodulator,
- wherein said demodulator comprises noise predicting means for predicting an amount of ingress noise in the digital signal and subtracting means for subtracting the predicted amount of ingress noise from the digital signal.
A method for reducing ingress noise in a digital signal, comprising:
- predicting an amount of ingress noise in the digital signal;
- and
- subtracting the predicted amount of ingress noise from the digital signal.
Dependencies are inferred from the claim text.