UWB Receiver Filtering and Ranging With Low-Precision Clocking
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Solution Overview
Problem
Ultra-wideband (UWB) wireless communication systems face challenges in achieving low power consumption and precise range finding without the need for additional complex components like GPS or ultrasonic/laser range finding circuits, while maintaining robustness in noisy environments.
Innovation Solution
The implementation of an N-path filter using a low precision clock source in combination with an energy detector within a UWB receiver, allowing for synchronization and range calculation between UWB transceivers through synchronized pulse bundles and energy integration windows, eliminating the requirement for accurate carrier waves and additional hardware.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If GPS or ultrasonic/laser range finding circuits are added to achieve precise range finding, then measurement precision is improved, but device complexity and power consumption increase
Solution Approach 1:
The UWB transceiver is designed to perform both communication and range finding functions using the same hardware components. The bi-directional time of flight measurement mechanism enables the system to determine distance between devices while simultaneously establishing communication links, eliminating the need for separate GPS or ultrasonic range finding circuits.
Solution Approach 2:
The system uses its own transmitted UWB pulses as the measurement signal for range finding, rather than requiring external dedicated ranging signals. The transceiver measures the time of flight of its own signals reflected from or transmitted to other UWB-equipped devices, making the ranging capability self-sufficient and integrated into the communication function.
2Measurement precision
If additional hardware components are added for range finding, then measurement precision is improved, but power consumption increases
Solution Approach 1:
The same UWB transceiver hardware that communicates data is also used for range finding measurements. The bi-directional time of flight measurement uses the communication signals themselves as the measurement carrier, so no additional power-consuming ranging hardware is required.
Solution Approach 2:
The system performs range finding measurements periodically by exchanging UWB pulse bundles at specific intervals. This periodic measurement approach allows the system to maintain accurate distance information while keeping the ranging function dormant during non-measurement periods, reducing overall power consumption compared to continuous operation.
3Measurement precision
If high precision clock sources are used for accurate pulse timing, then measurement precision is improved, but power consumption and device complexity increase
Solution Approach 1:
The system changes the timing reference parameter from requiring high-precision clock synchronization to using time stamping at packet boundaries. By measuring the time of flight based on packet transmission and reception times rather than individual pulse timing, the system achieves accurate range finding using lower precision, lower power clock sources.
Solution Approach 2:
The system applies time stamping and time of flight measurement only to the necessary packet boundaries rather than requiring continuous high-precision timing throughout the communication. This partial application of precise timing measurement achieves sufficient ranging accuracy without the continuous power consumption of high-precision clock synchronization.
4Use of energy by moving object
If N-path filter with low precision clock is used, then power consumption is reduced, but filtering precision deteriorates
Solution Approach 1:
The system uses multiple parallel paths (N-path filter) that are simpler copies of basic filtering stages, each driven by a low-precision clock. By combining the outputs of these parallel simple paths, the system achieves the necessary filtering performance without requiring any single path to use high-precision, high-power clock sources.
Solution Approach 2:
The filtering function is divided into multiple parallel N-path filter stages, each handling a portion of the frequency spectrum. This segmentation allows each individual path to use low-precision clocking while the aggregate of all paths provides the overall filtering performance needed for the UWB receiver.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution enables low power consumption UWB systems to perform accurate range finding and communication with reduced complexity and power consumption, maintaining robustness in noisy environments without the need for additional hardware, thus enhancing the feasibility of self-powered wireless sensor networks.
Implementation Method 1
The implementation of an N-path filter using a low precision clock source in combination with an energy detector within a UWB receiver
Implementation Method 2
processing the received plurality of UWB pulse bundles upon the second UWB transceiver; synchronizing to a predetermined pulse within the UWB pulse bundles
Implementation Method 3
starting a first timer associated with the first UWB transceiver upon transmission of the last pulse bundle; starting a second timer associated with the second UWB transceiver upon determining detection of the predetermined pulse
Data Source
AI summary
Ultra-Wideband (UWB) technology exploits modulated coded impulses over a wide frequency spectrum with very low power over a short distance for digital data transmission. Such UWB systems through their receivers may operate in the presence of interfering signals and should provide for robust communications. Accordingly, an accurate and sharp filter that operates at low power is required and beneficially one that does not require a highly accurate power heavy clock. Further, many UWB applications require location and/or range finding of other elements and it would therefore be beneficial to provide a UWB based range finding and/or location capability removing the requirement to add additional device complexity and, typically significant, power consumption.