Ranging Method Resolving Phase Ambiguity
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Solution Overview
Problem
Narrowband and multi-carrier phase difference methods for radio signal transceiver ranging are susceptible to 180-degree phase ambiguity, affecting the accuracy of one-way frequency domain channel response reconstruction and direction of arrival estimation in multiple-antenna setups.
Innovation Solution
A method that utilizes measurement results from multiple antenna combinations to calculate a corrected estimate of the one-way frequency domain channel response by leveraging spatial phase information, eliminating the phase ambiguity through comparison values and metric distances, allowing for more reliable distance and angle calculations between radio signal transceivers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If two-way phase measurements are used to estimate one-way frequency domain channel response, then phase measurement offsets between transceivers cancel out, but 180-degree phase ambiguity remains in the reconstructed channel response
Solution Approach 1:
The patent introduces an intermediary reference signal with known phase characteristics that mediates between the two transceivers. This reference signal serves as a common reference frame that allows resolution of the 180-degree phase ambiguity while maintaining the offset cancellation benefit of two-way measurements
Solution Approach 2:
The patent changes the parameter being measured by introducing additional measurement dimensions (e.g., measuring both in-phase and quadrature components, or using multiple frequencies). This parameter expansion provides enough information to disambiguate the 180-degree phase uncertainty
2Adaptability or versatility
If multiple antennas with spatial configuration are used for phase-based ranging, then direction of arrival reconstruction is enabled, but 180-degree phase ambiguity affects spatial domain reconstruction
Solution Approach 1:
The patent resolves the spatial domain phase ambiguity by transitioning to another dimension - using temporal dimension (multiple time samples) or frequency dimension (multiple frequencies) to provide additional constraints that resolve the spatial 180-degree ambiguity
Solution Approach 2:
The patent segments the channel response estimation into multiple independent estimates from different antenna pairs or different time/frequency instances. By combining these segmented estimates, the system can resolve the phase ambiguity that affects individual estimates
Data Source
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AI summary
A method of ranging between a first and a second radio signal transceiver, comprises calculating (4a) a preliminary estimate of a value proportional to a one-way frequency domain channel response, for a frequency of a plurality of frequencies and for each of a first antenna combination and a second antenna combination of a plurality of antenna combinations, based on, from a first set of measurement results, the measurement results for said frequency and the respective said antenna combination, and, from said second set of measurement results, said phase value for said frequency and the respective said antenna combination, or, optionally, the measurement results for said frequency and the respective said antenna combination; calculating (4b) a comparison value for said preliminary estimate, for said frequency and for each of said first antenna combination and said second antenna combination, based on, from one of said first set or said second set of measurement results, the phase value for said frequency and the respective said antenna combination, or, optionally, the measurement results for said frequency and the respective said antenna combination; and determining (6), for said frequency and said first antenna combination, a corrected estimate of said value proportional to said one-way frequency domain channel response, based on said preliminary estimate and said comparison value, for said first antenna combination and said second antenna combination; and performing (8) a ranging calculation between said first and said second radio signal transceiver based on a plurality of such corrected estimates.