Matched Filter Bank Feedback for Sensitive Radio Symbol Decoding

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 requiring more filters, by feeding back earlier decoded symbols into the matched filter bank or decision unit.

Engineering Contradictions & Design Principles

VSEngineering 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

Engineering Contradiction:

ImprovesensitivityVSAvoidnumber of filters

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent segments the decoding process into two stages: first, a reduced matched filter bank with fewer filters performs initial correlation to produce soft bit decisions; second, a sequential decoder uses these soft decisions to progressively refine bit estimates by comparing against multiple possible bit sequences. This segmentation allows achieving high sensitivity (equivalent to long filter lengths) without implementing the full exponential number of filters required by a conventional long-K matched filter bank.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent performs preliminary decoding using a reduced filter bank to generate soft bit decisions before the final decoding stage. These preliminary soft decisions are then used to guide the sequential decoding process, effectively preparing the system in advance to achieve high sensitivity without requiring the full computational resources of a complete long-K filter bank.

Inventive Principle:

Principle #10Preliminary action

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 increases

Engineering Contradiction:

ImprovesensitivityVSAvoidpower consumption

Core Design Contradiction:

Measurement precisionVSUse of energy by moving object

Solution Approach 1:

The patent segments the decoding process into two stages: first, a reduced matched filter bank with fewer filters performs initial correlation to produce soft bit decisions; second, a sequential decoder uses these soft decisions to progressively refine bit estimates by comparing against multiple possible bit sequences. This segmentation allows achieving high sensitivity (equivalent to long filter lengths) without implementing the full exponential number of filters required by a conventional long-K matched filter bank.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent performs preliminary decoding using a reduced filter bank to generate soft bit decisions before the final decoding stage. These preliminary soft decisions are then used to guide the sequential decoding process, effectively preparing the system in advance to achieve high sensitivity without requiring the full computational resources of a complete long-K filter bank.

Inventive Principle:

Principle #10Preliminary action

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 increases

Engineering Contradiction:

ImprovesensitivityVSAvoidarea of demodulator

Core Design Contradiction:

Measurement precisionVSArea of stationary object

Solution Approach 1:

The patent segments the decoding process into two stages: first, a reduced matched filter bank with fewer filters performs initial correlation to produce soft bit decisions; second, a sequential decoder uses these soft decisions to progressively refine bit estimates by comparing against multiple possible bit sequences. This segmentation allows achieving high sensitivity (equivalent to long filter lengths) without implementing the full exponential number of filters required by a conventional long-K matched filter bank.

Inventive Principle:

Principle #1Segmentation

Data Source

PatentUS11863362B2Matched filter bank

Publication Date: 2024.01.02 NORDIC SEMICONDUCTOR

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.