Isofrequency Retransmission Coupling Echo Cancellation
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Solution Overview
Problem
Current isofrequency retransmission techniques in digital terrestrial broadcasting suffer from coupling echoes between receiving and transmitting antennas, leading to signal disturbances and reduced coverage, as existing echo cancellation methods are inefficient due to adaptive algorithms requiring heavy computing resources and providing only partial echo cancellation.
Innovation Solution
A method involving precise extraction and processing of coupling echoes to generate a correction signal, which is then subtracted from the received signal, allowing for complete digital regeneration and cancellation of coupling echoes, along with other distortions like phase noise and fading, using deformation parameters such as gain, delay, and phase.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If isofrequency retransmission is used to extend coverage area, then coverage area is improved, but coupling echoes between receiving and transmitting antennas cause signal disturbances and reduce transmission quality
Solution Approach 1:
The patent extracts the harmful coupling echo signal from the received signal by identifying it as a distinct component that can be separated and eliminated through digital signal processing, allowing the useful signal to be recovered without distortion
Solution Approach 2:
The patent changes the parameters of the coupling echo signal (amplitude, phase, delay) to match the actual measured coupling characteristics, then uses these adjusted parameters to generate a correction signal that accurately cancels the echo interference
2Object-affected harmful factors
If conventional echo cancellation methods using adaptive algorithms are used, then some echo suppression is achieved, but heavy computing resources are required and only partial echo cancellation is provided
Solution Approach 1:
The patent replaces complex adaptive filtering algorithms with a direct measurement and subtraction approach, using the measured coupling parameters to directly compute and subtract the echo signal without requiring iterative adaptive processing
Solution Approach 2:
The patent performs preliminary measurement of the coupling parameters (amplitude, phase, delay) between transmitting and receiving antennas before normal operation, storing these parameters for use in real-time echo cancellation without requiring complex processing during signal transmission
3Stability of the object's composition
If coupling echo level is reduced to prevent system locking, then transmission stability is improved, but transmission power must be reduced limiting coverage area
Solution Approach 1:
The patent converts the harmful coupling echo into a useful measurement tool by using the echo signal itself to determine the coupling parameters, then applying these parameters to generate a correction signal that eliminates the harmful effects while maintaining full transmission power
Data Source
Figure 1~2
Figure 3
Figure 4A~4B
AI summary
The method involves extracting a coupling echo using a coupling echo extraction module (33) and processing the echo so as to generate a correction signal. The correction signal is subtracted from a source signal to generate an improved signal, and the improved signal is regenerated, using a digital regeneration module (36), by demodulation/modulation so as to be retransmitted on a transmitting antenna (32). The extraction of the echo implements a determination of a deformation parameter of signal to be re-emitted on the antenna. Independent claims are also included for the following: (1) a device for isofrequency retransmission of a digital signal (2) a computer program product comprising program code instructions for implementing steps of a digital signal retransmission method.