Local Oscillator Synchronization for Accurate Channel Sounding Ranging
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Solution Overview
Problem
Current network protocols face challenges in accurately determining the distance between network devices using Channel Sounding due to phase ambiguity between transmit and receive circuits, which can vary and complicate distance measurements.
Innovation Solution
A system and method that ensures a constant phase relationship between the transmit and receive circuits by using a clock generation circuit with a phase locked loop and dividers outside the phase locked loop, initialized to a predetermined state, to generate clocks with a guaranteed phase difference, thereby stabilizing the phase relationship for accurate distance calculations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If phase based ranging is used to determine distance between network devices, then distance measurement capability is provided, but phase ambiguity between transmit and receive circuits causes measurement inaccuracy
Solution Approach 1:
The clock generation is segmented into separate transmit and receive clock generation circuits, each with its own phase locked loop and divider. This segmentation allows independent control and initialization of each clock path, ensuring that the phase relationship between transmit and receive clocks can be maintained constant despite variations in individual circuit phases.
Solution Approach 2:
The dividers in both transmit and receive clock generation circuits are initialized to a predetermined state before operation begins. This preliminary initialization ensures that the phase relationship between transmit and receive clocks is established and maintained constant, eliminating phase ambiguity that would otherwise cause measurement inaccuracies.
2Adaptability or versatility
If the phase relationship between transmit and receive circuits is allowed to vary, then circuit flexibility is maintained, but distance measurement accuracy deteriorates
Solution Approach 1:
The phase relationship parameter is changed from variable to constant by initializing the dividers to a predetermined state. This parameter change ensures that while the circuits can still operate flexibly with different frequencies and configurations, the critical phase relationship between transmit and receive clocks remains constant, enabling accurate distance measurements.
3Device complexity
If dividers are placed inside the phase locked loop, then clock generation is simplified, but phase relationship between transmit and receive clocks becomes unpredictable
Solution Approach 1:
The dividers are extracted from inside the phase locked loop and placed outside it in both transmit and receive clock generation circuits. This extraction allows the phase locked loops to maintain frequency locking while the external dividers can be independently initialized to a predetermined state, ensuring predictable and constant phase relationships between transmit and receive clocks without significantly increasing overall system complexity.
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 approach ensures predictable and accurate distance measurements between network devices by maintaining a constant phase difference between transmit and receive clocks, enhancing the reliability of Channel Sounding applications.
Implementation Method 1
A system and method for accurately determining a distance between two network devices using a Channel Sounding application is disclosed. The network devices each guarantee a fixed phase relationship between the transmit circuit and the receive circuit.
Implementation Method 2
The first network device and the second network device each comprise a clock generation circuit having a phase locked loop and at least one divider disposed outside the phase locked loop to generate a receive clock and a transmit clock, such that a phase difference between the transmit clock and the receive clock is constant.
Implementation Method 3
at least one divider disposed outside the phase locked loop to generate a receive clock and a transmit clock, such that a phase difference between the transmit clock and the receive clock is constant
Data Source
AI summary
A system and method for accurately determining a distance between two network devices using a Channel Sounding application is disclosed. The network devices each guarantee a fixed phase relationship between the transmit circuit and the receive circuit. In one embodiment, this is achieved by disposing the divider outside the phase locked loop and using the output of the divider to create the clocks for both the transmit circuit and receive circuit. In another embodiment, one or more dividers are disposed outside the phase locked loop, each having a reset, such that they can be initialized to a predetermined state. Further, by utilizing a divider with a reset, the quadrature signal generator is guaranteed to output clocks for the transmit circuit and the receive circuit that have a constant phase relationship.