Satellite Echo Noise Reduction via Dynamic Signal Replica
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Solution Overview
Problem
Conventional echo suppression techniques used in telephony are not applicable to satellite communications due to transponder distortion and large bandwidths, leading to a need for noise reduction methods that can scale, delay, and distort transmitted signals to compensate for echo noise effects.
Innovation Solution
A process that computes a scaled, delayed, and distorted replica of the transmit signal to compensate for satellite transponder nonlinearities and reduce echo noise in satellite communications, involving decimation through filters, Doppler tracking, and least mean square fractional sample delay to minimize bit error rate degradation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If conventional echo suppression techniques are used in satellite communications, then echo noise reduction is achieved, but the techniques cannot properly handle transponder distortion and large bandwidths
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting the echo canceller's scaling factors, delay elements, and distortion characteristics to match the actual transponder response. The system continuously adapts these parameters based on feedback signals to compensate for varying transponder distortion and maintain effective echo suppression across different bandwidth conditions.
Solution Approach 2:
The invention implements dynamics by making the echo canceller adaptable rather than fixed. The system dynamically adjusts its characteristics to match the transponder's time-varying response, enabling it to handle changing distortion conditions and bandwidth requirements in real-time satellite communications.
2Productivity
If the hub transmits high rate data to remote stations, then data transmission efficiency is improved, but the required C/N ratios become higher for hub signals
Solution Approach 1:
The patent employs feedback mechanisms where the hub receives echo signals from remote stations and uses these feedback signals to adjust the echo canceller parameters. This feedback loop enables the system to compensate for the higher C/N ratio requirements by continuously adapting to signal conditions, thereby maintaining reliable communication at high data rates.
3Object-affected harmful factors
If echo cancellation is performed at remote stations, then echo noise is reduced, but the returned transmit signals are much weaker and require complex processing
Solution Approach 1:
The invention extracts the echo cancellation function primarily to the hub station rather than distributing it to all remote stations. By concentrating the complex echo cancellation processing at the hub where the echo signals are strongest, the system reduces the processing burden on remote stations while still achieving effective echo noise reduction across the network.
Data Source
AI summary
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.