Matched Filter Bank Using Symbol Feedback for Receiver Sensitivity
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Solution Overview
Problem
Digital radio receivers face challenges in increasing sensitivity without exponentially increasing complexity and power consumption due to the need for longer bit-length filters, which is undesirable for power-constrained devices.
Innovation Solution
A method and apparatus that uses previously decoded symbols to influence the decoding of current symbols, effectively increasing the demodulation length without adding more filters, by applying a matched filter bank to a sampled radio signal and utilizing a decision unit to generate decoded symbols based on earlier decoded symbols.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the bit-length of each filter is increased to increase sensitivity, then the sensitivity of the receiver is improved, but the number of filters and computational complexity increases exponentially
Solution Approach 1:
The patent implements feedback by using previously decoded symbols to influence the decoding of current symbols. The decision unit generates decoded symbols and feeds them back to the matched filter bank, where they are used to update the filter sequences for subsequent decoding operations. This feedback mechanism allows the system to effectively increase the bit-length used for sensitivity without adding more filters, as the same filters are reused with updated sequences based on decoded information.
2Measurement precision
If the bit-length of each filter is increased to increase sensitivity, then the sensitivity of the receiver is improved, but the power consumption increases
Solution Approach 1:
By using feedback to update filter sequences with previously decoded symbols, the system achieves higher sensitivity without increasing the number of filters or computational operations. The same hardware resources are reused more efficiently, avoiding the exponential increase in power consumption that would result from adding more filters for increased bit-length.
Solution Approach 2:
The patent changes the parameter of filter sequences by updating them with previously decoded symbols rather than increasing the number of filters. This parameter change approach allows the system to achieve higher sensitivity through better utilization of existing filters with updated sequences, rather than through hardware expansion that would increase power consumption.
3Measurement precision
If the bit-length of each filter is increased to increase sensitivity, then the sensitivity of the receiver is improved, but the hardware complexity increases
Solution Approach 1:
The feedback mechanism updates the filter sequences using previously decoded symbols, allowing the same hardware filters to achieve higher sensitivity through intelligent reuse. This avoids the need for additional hardware filters that would be required if sensitivity were increased by extending filter bit-length directly, thereby maintaining hardware complexity at acceptable levels.
Data Source
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AI summary
A radio receiver (1) comprises a matched filter bank (5) and a decision unit (6). The matched filter bank (5) has a plurality of filter modules for generating correlation-strength data from a sampled radio signal, each filter module being configured to cross-correlate the sampled signal with data representing a respective filter sequence. Each filter sequence comprises a respective constant portion and a respective variable portion, the variable portion being positioned before the constant portion. The decision unit (6) is configured to use the correlation-strength data to generate a sequence of decoded symbols from the sampled signal. The matched filter bank (5) and/or decision unit (6) are configured to determine the value of each symbol in the sequence in part based on the value of a respective earlier decoded symbol from the sequence of decoded symbols, wherein each constant portion is constant over time, and wherein each variable portion depends on the earlier decoded symbol.