Selective ACI Suppression via Energy Detection
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Solution Overview
Problem
Existing radio communication systems face challenges in effectively suppressing adjacent channel interference (ACI) without degrading receiver sensitivity, as current methods either compromise on interference suppression or suffer from suboptimal performance due to limited sample sizes and computational complexity.
Innovation Solution
Implementing a selective ACI suppression system that uses pre-determined narrow bandpass/lowpass filters only when necessary, combined with an energy detector to determine the presence of ACI, and optional additional processing such as adaptive filtering and blind detection to enhance interference suppression.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If preset bandpass or lowpass filters are used to suppress ACI, then ACI suppression is improved, but receiver sensitivity deteriorates
Solution Approach 1:
The filter bandwidth is made dynamic rather than fixed. The system adapts the filter bandwidth based on the detected signal characteristics and interference conditions, allowing narrow bandwidth for ACI suppression when needed and wider bandwidth for maintaining sensitivity when interference is absent or minimal.
Solution Approach 2:
The filter parameters (bandwidth, cutoff frequencies) are changed based on operating conditions. The system adjusts filter characteristics dynamically to match the actual interference environment, optimizing both ACI suppression and signal reception performance under different conditions.
2Object-affected harmful factors
If narrow bandpass/lowpass filters are used to suppress ACI, then ACI suppression is improved, but co-channel interference suppression deteriorates
Solution Approach 1:
The filter bandwidth dynamically adapts to the interference scenario. When ACI is detected, the bandwidth narrows to suppress adjacent channels. When co-channel interference is present, the bandwidth widens to maintain suppression capability, allowing the system to handle different interference types appropriately.
Solution Approach 2:
The system periodically evaluates the interference environment and adjusts filter parameters accordingly. This continuous adaptation allows the filter to respond to changing interference conditions, maintaining effectiveness against both ACI and co-channel interference over time.
3Reliability
If wider filters are used for 8PSK modulation to reduce ISI, then receiver sensitivity is improved, but ACI suppression deteriorates
Solution Approach 1:
The filter bandwidth dynamically adapts based on modulation type and interference conditions. For 8PSK modulation, the system uses wider filters to reduce ISI and maintain sensitivity, but when ACI is detected, it narrows the bandwidth to suppress adjacent channel interference, balancing both requirements.
Solution Approach 2:
The filter parameters are changed based on the modulation scheme being used. The system optimizes filter characteristics for different modulations (e.g., wider for 8PSK to reduce ISI) while maintaining the ability to suppress ACI when present through adaptive parameter adjustment.
4Object-affected harmful factors
If adaptive ACI suppression algorithms are used, then ACI suppression is improved when interference is present, but computational complexity increases
Solution Approach 1:
The ACI suppression function is segmented into distinct processing stages: signal detection, interference analysis, filter parameter selection, and filtering. This modular approach allows efficient computation by breaking down the complex adaptive algorithm into manageable steps that can be executed sequentially with optimized computational resources.
Data Source
AI summary
Adjacent channel interference (ACI) suppression is achieved by selectively applying one or more pre-calculated fixed filters only when necessary, thereby preserving the sensitivity of the receiver. An energy detector accurately detects adjacent channel interference in the frequency band of the desired signal so that the likelihood of a false detection of ACI is very low. If the energy detector detects adjacent channel interference is present in the band of the desired signal, then the received signal is selected to be filtered by the pre-calculated filter, e.g., a low pass filter. Otherwise, the pre-calculated filter is bypassed. In either case, additional ACI suppression processing may be employed.