Receiver Interference Detection Using AGC Settling Windows
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Solution Overview
Problem
Communication systems face interference issues due to co-channel and adjacent channel interference, leading to data distortion and system malfunction, as receivers often misinterpret interference signals as data, causing false alarms and data loss.
Innovation Solution
A system and method that utilize a control module in a receiver to generate signals based on the automatic gain control module's settling behavior, distinguishing between data and interference signals by monitoring the ADC output within a predetermined time period, thereby preventing false alarms and resetting the receiver to prevent data loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the peak detector module generates a peak-detect signal when the input signal exceeds the RSSI threshold, then data reception is activated, but false alarms occur when interference signals are mistaken for data
Solution Approach 1:
The system performs preliminary actions by generating a first signal when the AGC gain settles at a non-nominal value, and then monitors for a second signal within a predetermined time window before making the final interference determination. This preliminary monitoring phase allows the system to distinguish between actual data packets and interference signals by checking whether valid data processing occurs within the expected time frame.
Solution Approach 2:
The system uses feedback from the data processing module to determine whether interference is present. If the data processing module fails to generate the expected second signal within the predetermined time period, this feedback indicates that the initial peak-detect signal was triggered by interference rather than valid data, allowing the system to reset and prevent false alarm propagation.
2Loss of information
If the receiver processes all signals exceeding the threshold, then no data is lost, but system performance degrades due to processing interference signals
Solution Approach 1:
The system performs preliminary validation by checking whether the data processing module generates the expected second signal within a predetermined time window after the AGC gain settles. This preliminary check occurs before full data processing is committed, allowing the system to identify and discard interference signals early without wasting extensive processing resources.
Solution Approach 2:
The system performs a partial processing action by monitoring for the second signal within a limited time window rather than fully processing all signals that exceed the threshold. This partial action is sufficient to distinguish between valid data and interference, preventing excessive processing of false alarms while maintaining adequate data detection capability.
3Adaptability or versatility
If the AGC gain is dropped in response to a peak-detect signal, then the receiver adapts to strong signals, but the gain may not return to normal when the signal is interference
Solution Approach 1:
The system uses feedback from the data processing module to determine whether to restore the AGC gain. If the data processing module successfully generates the second signal within the predetermined time period, this feedback confirms that the input was valid data and the AGC gain is restored. If no second signal is generated, the feedback indicates interference was detected and the AGC gain remains dropped, preventing false recovery that would lead to repeated false alarms.
Solution Approach 2:
The system performs a preliminary check by monitoring for the second signal within a predetermined time window before committing to AGC gain recovery. This preliminary validation ensures that the AGC gain is only restored when valid data is confirmed, not when interference is present, thereby maintaining reliable gain adaptation.
Data Source
AI summary
A receiver including an automatic gain control module, a digital signal processor module, and a control module. The automatic gain control module has a gain that varies from a nominal value in response to the receiver receiving an input signal. The automatic gain control module is configured to generate a first signal in response to the gain settling at a value different from the nominal value. In response to the input signal not being an interference signal, the digital signal processor module is configured to process the input signal and generate a second signal. Subsequent to the first signal being generated and prior to the second signal being generated, the control module is configured to determine whether the input signal is an interference signal based on whether the second signal is generated within a predetermined time period subsequent to the first signal being generated.