Receiver Circuit Co-Channel Interference Suppression
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Solution Overview
Problem
Current receiver systems face challenges in effectively mitigating co-channel interference (CIC) in In-band on-channel (IBOC) digital radio broadcasting, particularly due to strong interference from adjacent FM channels, which can distort digitally modulated sidebands and reduce signal quality.
Innovation Solution
The proposed receiver system employs multiple antennae to determine angles of arrival for different frequency bins, using weighting values to constructively or destructively combine antenna signals based on angle differences, thereby reducing interference and enhancing signal quality through spatial covariance matrix analysis and beamforming techniques.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If multiple antennae are used to determine angles of arrival and apply weighting values for signal combining, then co-channel interference suppression is improved, but device complexity increases
Solution Approach 1:
The receiver system segments the signal processing by separating different frequency bins (first-frequency-bin and second-frequency-bin) and processing them through different weighting determination blocks. Each frequency bin is handled independently with its own angle-of-arrival determination and weighting application, allowing selective interference suppression without processing the entire signal spectrum uniformly.
Solution Approach 2:
The patent introduces spatial dimension processing by using multiple antennae to determine angles of arrival. This adds a spatial domain dimension to the frequency domain processing, enabling the system to distinguish and suppress interference signals based on their directional characteristics while maintaining the original frequency bin structure.
2Reliability
If angle-of-arrival determination is performed for multiple frequency bins with selective weighting, then signal quality is improved, but processing time increases
Solution Approach 1:
The processing is segmented into parallel paths for different frequency bins. The first-AoA-block and second-AoA-block determine angles for their respective frequency bins simultaneously, and the first-weighting-determination-block and second-weighting-determination-block operate in parallel. This segmented parallel processing improves signal quality through selective combining while reducing overall processing time compared to sequential handling.
Solution Approach 2:
The system applies angle-of-arrival determination and selective weighting only to specific frequency bins where interference is present, rather than processing the entire signal spectrum. By identifying and processing only the affected first-frequency-bin and second-frequency-bin, the system achieves improved signal quality without the time cost of exhaustive full-spectrum processing.
3Object-affected harmful factors
If destructive combining is applied to suppress interference, then interference reduction is improved, but signal strength may be reduced
Solution Approach 1:
The weighting determination blocks apply different combining strategies to different frequency bins based on local conditions. The first-weighting-determination-block applies destructive combining to the first-frequency-bin where interference is present, while the second-weighting-determination-block applies constructive combining to the second-frequency-bin to maintain signal strength. This localized adaptive approach ensures interference suppression without unnecessary signal attenuation.
Solution Approach 2:
The system dynamically changes the weighting parameters applied to different frequency bins based on angle-of-arrival measurements. By adjusting the weighting values according to the spatial characteristics of signals in each frequency bin, the system can switch between destructive combining (for interference suppression in first-frequency-bin) and constructive combining (for signal enhancement in second-frequency-bin), optimizing both interference reduction and signal strength preservation.
Data Source
AI summary
A receiver system comprising: an input terminal configured to receive input signalling comprising a plurality of antenna-signals, wherein the plurality of antenna-signals each comprise information that corresponds to a first-frequency-bin and a second-frequency-bin. AoA-blocks can determine a first-angle-of-arrival and a second-angle-of-arrival associated with the first- and second-frequency-bins. A first-weighting-determination-block configured to, based on the first-angle-of-arrival and the second-angle-of-arrival, either: set first-weighting-values as values for constructively combining the information that corresponds to the first-frequency-bins of the plurality of antenna-signals; or set first-weighting-values as values for destructively combining the information that corresponds to the first-frequency-bins of the plurality of antenna-signals.