RSSI Pattern Detection Without OOK Demodulation
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Solution Overview
Problem
Connected objects in the Sigfox network face challenges in detecting digital patterns within modulated beacon signals without using an OOK demodulator, due to the complexity and bulk associated with implementing such demodulators, especially in simple sensor architectures.
Innovation Solution
The method employs circularly addressable memory means to store RSSI values indicative of signal intensity at the modulation frequency, accumulating these values to identify patterns by detecting cumulative peaks, which allows for the detection of digital patterns within modulated signals using 'soft bits' and signal-to-noise analysis, eliminating the need for an OOK demodulator.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an OOK demodulator is implemented to detect digital patterns in modulated signals, then detection reliability is improved, but device complexity and surface bulk increase
Solution Approach 1:
The patent extracts only the essential detection functionality needed for pattern recognition, eliminating the need for a complete OOK demodulator. By using circularly addressable memory means to accumulate RSSI values and detect patterns through peak identification, the solution separates the detection function from the full demodulation process, reducing device complexity while maintaining detection reliability for the specific application of identifying digital patterns in beacon signals
Solution Approach 2:
The patent uses circularly addressable memory means that replicate the pattern structure in memory, allowing the system to compare received signal characteristics against stored pattern templates. This copying approach enables pattern detection through accumulation and comparison rather than full demodulation, simplifying the device architecture while preserving detection capability
2Reliability
If an OOK demodulator is implemented to detect digital patterns in modulated signals, then detection reliability is improved, but surface bulk increases
Solution Approach 1:
The patent extracts only the essential detection functionality needed for pattern recognition, eliminating the need for a complete OOK demodulator. By using circularly addressable memory means to accumulate RSSI values and detect patterns through peak identification, the solution separates the detection function from the full demodulation process, reducing surface bulk while maintaining detection reliability for the specific application of identifying digital patterns in beacon signals
Solution Approach 2:
The patent applies local quality by using specialized circularly addressable memory structures optimized for pattern detection rather than general-purpose demodulation components. The memory means are configured with specific sizes matching the digital patterns being detected, creating a localized, efficient detection mechanism that reduces overall device surface area compared to a full OOK demodulator
3Device complexity
If circularly addressable memory means are used to accumulate RSSI values for pattern detection, then device complexity is reduced, but detection precision may be affected
Solution Approach 1:
The patent applies preliminary action by pre-configuring circularly addressable memory means with sizes matching the expected digital pattern lengths and pre-establishing the accumulation process. The memory structures are prepared in advance with the correct addressing scheme, allowing RSSI values to be accumulated over complete pattern periods. This preliminary setup ensures that detection precision is maintained through proper synchronization and complete pattern coverage, while the overall device complexity remains reduced compared to full demodulation
4Reliability
If acquisition time is extended to improve pattern detection accuracy, then detection reliability is improved, but productivity decreases
Solution Approach 1:
The patent applies periodic action by using the natural periodicity of the beacon signal and the circular addressing of memory means to accumulate RSSI values over complete pattern periods. The acquisition time is set to integer multiples of the pattern period, allowing detection to occur at regular intervals without requiring excessively long observation times. This periodic approach maintains detection reliability through sufficient signal samples while improving productivity by enabling detection at predictable, regular intervals rather than requiring continuous long-term monitoring
Data Source
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AI summary
We use as many circularly addressable memory units (MMA, MMB, MMC) as there are possible modulating digital patterns, each with a size corresponding to the pattern size. These sizes are coprime. These memory units are addressed circularly, at the rate of a timing signal with the modulation frequency. Indicative values of the signal intensity (VRSSIk) are extracted at the rate of this timing signal. Each extracted value is stored in parallel in the addressed memory locations of the memory units, by accumulating this value with the contents of the corresponding memory location. These operations are repeated for an acquisition time much longer than the time required to fully address the largest memory unit. An analysis of the contents of the memory locations of the memory units allows us to detect the possible presence of a pattern within the signal.