Noise reduction system and method thereof
First Claim
Patent Images
1. A method for reducing echo noise in satellite communications, the method comprising the steps of:
- transmitting a transmit signal from a hub to multiple remote stations, where the transmit signal contains at least one carrier;
storing a replica of the transmit signal;
distorting the replica according to satellite transponder nonlinearities;
determining a scaled, delayed and distorted replica of the transmit signal to provide a compensated distorted replica of the transmit signal;
using the compensated distorted replica to compensate for satellite transponder nonlinearities and reduce echo noise from a received aggregate signal received by the hub from the multiple remote stations;
wherein the determining step further comprises applying a block conversion to the transmit signal to form the distorted replica occupying a predetermined frequency range;
wherein the determining step further comprises correcting means for correcting for distortion in the aggregate signal by determining normalized gain and phase error in the aggregate signal to compute the replica of an echo noise signal; and
wherein the determining step further comprises second means for determining a delay in the aggregate signal by computing a least mean square fractional sample of the aggregate signal and tracking changes therein to determine the delay.
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Abstract
The reduction of echo noise in satellite communications includes receiving an aggregate signal from multiple remote stations, where the aggregate signal includes a transmit signal, whose bandwidth is in the range of 0.1 MHz to 66 MHz, is previously sent from a hub to the multiple receiving stations, computing a scaled, delayed and distorted replica of the transmit signal and using the replica to compensate for satellite transponder nonlinearities and reduce echo noise interference from a received aggregate signal received by the hub from the multiple remote stations.
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Citations
16 Claims
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1. A method for reducing echo noise in satellite communications, the method comprising the steps of:
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transmitting a transmit signal from a hub to multiple remote stations, where the transmit signal contains at least one carrier; storing a replica of the transmit signal; distorting the replica according to satellite transponder nonlinearities; determining a scaled, delayed and distorted replica of the transmit signal to provide a compensated distorted replica of the transmit signal; using the compensated distorted replica to compensate for satellite transponder nonlinearities and reduce echo noise from a received aggregate signal received by the hub from the multiple remote stations; wherein the determining step further comprises applying a block conversion to the transmit signal to form the distorted replica occupying a predetermined frequency range; wherein the determining step further comprises correcting means for correcting for distortion in the aggregate signal by determining normalized gain and phase error in the aggregate signal to compute the replica of an echo noise signal; and wherein the determining step further comprises second means for determining a delay in the aggregate signal by computing a least mean square fractional sample of the aggregate signal and tracking changes therein to determine the delay. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A system for reducing echo noise in satellite communications comprising:
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receiving means for receiving an aggregate signal from multiple remote stations, where the aggregate signal includes a distorted version of a transmit signal previously sent from a hub to the multiple remote stations; storing a replica of the transmit signal; distorting the replica according to satellite transponder nonlinearities; determining means for determining a scaled, delayed and distorted replica of the transmit signal to provide a compensated distorted replica of the transmit signal; echo noise reduction means for using the compensated distorted replica to compensate for satellite transponder nonlinearities and reduce echo noise from a received aggregate signal received by the hub from the multiple remote stations; wherein the determining means further comprises means for applying a block conversion to the transmit signal to form the distorted replica occupying a predetermined frequency range; wherein the determining means further comprises correcting means for correcting for distortion in the aggregate signal by determining normalized gain and phase error in the aggregate signal to compute the replica of an echo noise signal; and wherein the determining means further comprises second means for determining a delay in the aggregate signal by computing a least mean square fractional sample of the aggregate signal and tracking changes therein to determine the delay. - View Dependent Claims (9, 10, 11)
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12. An article of manufacture, comprising a non-transitory computer-readable medium having stored thereon instructions for echo noise in satellite communications, said instructions which, when performed by a processor, cause the processor to execute the steps comprising the steps of:
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receiving an aggregate signal from multiple remote stations, where the aggregate signal includes a distorted version of a transmit signal previously sent from a hub to the multiple remote stations; storing a replica of the transmit signal; distorting the replica according to satellite transponder nonlinearities; determining a scaled, delayed and distorted replica of the transmit signal to provide a compensated distorted replica of the transmit signal; using the compensated distorted replica to compensate for satellite transponder nonlinearities and reduce echo noise from a received aggregate signal received by the hub from the multiple remote stations; wherein the determining step further comprises applying a block conversion to the transmit signal to form the distorted replica occupying a predetermined frequency range; wherein the determining step further comprises correcting means for correcting for distortion in the aggregate signal by determining normalized gain and phase error in the aggregate signal to compute the replica of an echo noise signal; and wherein the determining step further comprises second means for determining a delay in the aggregate signal by computing a least mean square fractional sample of the aggregate signal and tracking changes therein to determine the delay. - View Dependent Claims (13, 14, 15, 16)
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Specification