Narrow-band Interference Cancellation via Adaptive Filtering and Variable Gain Amplification
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Solution Overview
Problem
Wireless receivers face challenges in recovering modulated signals due to narrow-band interference, which can be present in broadcast systems operating in the UHF region and caused by interactions with other channels, leading to IM2 and IM3 interferers that are difficult to filter effectively.
Innovation Solution
A receiver system incorporating an interference canceller with an adaptive filter and a digital variable gain amplifier (DVGA) to filter and amplify digital samples, using a least means squared algorithm to minimize interference and maintain signal power, while also including a bypass circuit to conserve power when interference is weak.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If narrow-band interference filtering is applied to recover modulated signals, then signal recovery capability is improved, but signal power may be reduced and additional processing complexity is introduced
Solution Approach 1:
The system uses a feedback mechanism where the output of the adaptive filter is fed back through the DVGA with variable gain. The DVGA adjusts its gain based on the filtered signal characteristics to compensate for power loss while maintaining the interference cancellation effect, thus resolving the contradiction between signal recovery and power maintenance
Solution Approach 2:
The DVGA dynamically changes its gain parameter to compensate for signal power reduction caused by filtering. By adjusting the gain parameter in response to the filtered signal conditions, the system maintains adequate signal power levels while preserving the interference cancellation benefits
2Object-affected harmful factors
If adaptive filtering is used to cancel narrow-band interference, then interference cancellation performance is improved, but device complexity and power consumption increase
Solution Approach 1:
The interference cancellation function is segmented into two distinct components: an adaptive filter for interference cancellation and a DVGA for power compensation. This segmentation allows each component to be optimized independently and provides flexibility to bypass either component when conditions permit, reducing overall system complexity in certain operating scenarios
3Reliability
If adaptive filtering and variable gain amplification are continuously applied, then signal quality in interference is improved, but power consumption increases
Solution Approach 1:
The system implements dynamic control where the DVGA gain is continuously adjustable based on signal conditions. This dynamic adaptation allows the system to use full processing power only when interference is present and signal quality degradation is detected, while reducing or bypassing processing when conditions are favorable, thus optimizing the trade-off between signal quality and power consumption
Data Source
AI summary
The disclosure is directed to a receiver. The receiver includes an interference canceller configured to filter digital samples produced from a modulated signal transmitted over a wireless channel, and a digital variable gain amplifier (DVGA) configured to amplify the filtered digital samples.