Matched Filter Bank Decoding Using Earlier Symbols for Higher 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 filter lengths in matched filter banks, which is undesirable for power-constrained devices.
Innovation Solution
The method involves using the value of previously decoded symbols to influence the decoding of current symbols, effectively increasing the length of the signal used for demodulation without increasing the number of filters, by feeding back earlier decoded symbols into the matched filter bank or decision unit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the bit-length K of each filter is increased to improve sensitivity, then the sensitivity of the receiver is improved, but the number of filters and multiply-accumulate operations increases exponentially
Solution Approach 1:
The patent applies preliminary action by using previously decoded symbols to inform current symbol decoding. The decision unit stores past decoded symbols and uses them to select subsets of filters or adjust correlation thresholds, effectively preparing decoding information in advance to reduce the need for exhaustive filter comparisons.
Solution Approach 2:
The patent segments the full set of filters into multiple subsets based on previously decoded symbol values. Instead of applying all filters to every symbol, the system divides the filter bank into manageable groups and selectively applies only relevant subsets, reducing the computational burden from exponential to linear complexity.
2Measurement precision
If the bit-length K of each filter is increased to improve sensitivity, then the sensitivity of the receiver is improved, but the power consumption significantly increases
Solution Approach 1:
The decision unit prepares decoding information in advance by storing previously decoded symbols and using them to pre-select relevant filter subsets before correlation operations. This preliminary preparation avoids the need to execute exhaustive filter comparisons, significantly reducing the number of multiply-accumulate operations and associated power consumption.
Solution Approach 2:
The patent applies partial action by using only a subset of available filters for each decoding operation rather than all filters. By leveraging previously decoded symbols to identify and apply only the necessary filter subsets, the system achieves adequate sensitivity with reduced computational effort and lower power consumption.
3Measurement precision
If the bit-length K of each filter is increased to improve sensitivity, then the sensitivity of the receiver is improved, but the area of the demodulator significantly increases
Solution Approach 1:
The patent segments the filter bank into multiple subsets organized according to previously decoded symbol values. This segmentation allows the system to physically implement fewer active filter circuits at any given time, reducing the overall demodulator area while maintaining the capability to achieve high sensitivity through selective filter application.
Solution Approach 2:
The decision unit stores previously decoded symbols in advance and uses this information to pre-determine which filter subsets will be needed. This preliminary action enables the system to configure only the necessary filter circuits for current decoding operations, minimizing the active hardware area while preserving sensitivity performance.
Data Source
AI summary
A radio receiver comprises a matched filter bank and a decision unit. The matched filter bank 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. The decision unit is configured to use the correlation-strength data to generate a sequence of decoded symbols from the sampled signal. The matched filter bank and/or decision unit 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.