Correlator-Based Radio Receiver for Low-Power Movement Detection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current radio receivers with high current consumption, such as those using PLL-based technology, limit the operational duration of battery-powered devices and introduce latency issues in polling methods, making them unsuitable for energy-saving applications that require long-term operation and precise movement detection.
Innovation Solution
A method and radio device that demodulate modulated radio signals using a correlator unit to determine the quality constant of received field strength, allowing for long-term movement detection without complex computing operations, using a correlator unit and a low-power receiver design that can operate for extended periods with minimal current consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If PLL-based standard radio receivers with RSSI signal are used, then the quality of received signal can be monitored, but the current consumption increases above 10 mA limiting operational duration
Solution Approach 1:
The patent extracts only the essential function of signal quality monitoring by using a simplified correlation-based receiver that determines reception quality through correlation values rather than implementing a full RSSI signal chain with logarithmic amplifiers. This extraction of the core monitoring function reduces current consumption from above 10 mA to below 100 μA while maintaining the ability to detect signal quality changes for movement detection
Solution Approach 2:
The patent employs a simplified receiver design that sacrifices some measurement precision compared to standard PLL-based receivers but achieves sufficient performance for movement detection. The correlation-based approach uses simpler circuitry with lower current consumption, accepting that the measurement is less precise than full RSSI but adequate for detecting significant movements
2Use of energy by moving object
If polling method is used to save current, then operational duration can be extended, but reaction time increases and radio channel becomes constantly occupied
Solution Approach 1:
The patent enables the receiver to continuously monitor signal quality without external polling by using the correlation-based measurement that can be performed autonomously at very low current consumption. The receiver independently determines reception quality and detects movements without requiring periodic activation by a master node, thus eliminating polling-induced latency while maintaining energy efficiency
Solution Approach 2:
The patent uses periodic transmission of location sequences by the master node at defined time intervals, which the passive receiver processes continuously. This periodic stimulation approach allows the receiver to remain in a low-power state between measurements while still providing timely movement detection, as the receiver is always ready to process incoming signals without requiring full activation
3Use of energy by moving object
If current-saving receiver with low current consumption is used, then operational duration extends to one year, but sensitivity and selectivity are reduced
Solution Approach 1:
The patent changes the measurement parameter from amplitude-based RSSI to correlation-based signal quality assessment. By using correlation values between received location sequences and expected sequences, the system achieves adequate measurement precision for movement detection with much lower current consumption. The correlation approach is more robust to noise and provides sufficient sensitivity for detecting significant movements without requiring high-gain amplifiers
4Measurement precision
If multiple distance estimates are required for positioning, then position can be determined in one plane, but the complexity of the system increases
Solution Approach 1:
The patent makes the passive receiver multi-functional by enabling it to perform both signal quality monitoring and movement detection using the same correlation-based measurement mechanism. The receiver processes location sequences to determine reception quality and simultaneously detects movements through quality changes, eliminating the need for separate positioning algorithms and reducing overall system complexity while maintaining positioning capability
Data Source
AI summary
The invention relates to a method and a radio device for detecting a movement of at least one receiver, wherein the radio signals are sent from at least one stationary transmitter to the at least one receiver and the received signals are evaluated for determining a movement. The radio signals are designed as a specified bit sequence modulated onto a high-frequency carrier and are demodulated by the receiver to form a receiving sequence that is correlated to determine correspondence with the specified bit sequences stored as a reference sequence. Dependent on the correspondence or errors that can be determined by the correlation, quality indicators for the receiving field strength of the received radio signals are determined, wherein the radio signals having the specified bit sequence are sent from the transmitter having at least two different transmission powers in a series. The series is repeated at temporal intervals and the quality indicators of the received sequences of the series are evaluated to determine a movement of the receiver in relation to the transmitter.