Multicarrier Phase Localization for Accurate OFDM Time-of-Arrival
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Solution Overview
Problem
Existing radio frequency localization methods face challenges in achieving high accuracy localization without occupying additional bandwidth, requiring hardware modifications, or additional communication protocol overhead.
Innovation Solution
A multicarrier phase-based localization method that utilizes orthogonal frequency division multiplexing (OFDM) in 4G or 5G networks to extract phase information from multicarrier signals, canceling out phase offsets through statistical estimation and multilateration, enabling accurate time-of-arrival calculations without additional bandwidth or hardware modifications.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If phase-based localization methods are implemented, then localization accuracy is improved, but additional bandwidth occupation occurs
Solution Approach 1:
The patent reuses existing multicarrier reference signals (such as CRS or PSS/SSS in LTE/5G) for dual purposes: both for channel estimation and for phase-based time-of-arrival measurement. This eliminates the need for dedicated localization bandwidth while achieving sub-meter accuracy through clever signal processing of existing signals.
Solution Approach 2:
The patent extracts phase information from existing reference signals and uses statistical estimation techniques to cancel phase offsets. By changing the measurement parameter from amplitude-based to phase-based detection and applying multilateration algorithms, the system achieves high accuracy without requiring additional signal bandwidth.
2Measurement precision
If hardware modifications are made to achieve high accuracy localization, then localization accuracy is improved, but device complexity increases
Solution Approach 1:
The patent replaces hardware-based localization solutions (such as dedicated localization antennas or specialized RF components) with software-based signal processing techniques. By using phase extraction and statistical estimation algorithms on existing received signals, the system achieves high accuracy without modifying the physical hardware architecture.
3Adaptability or versatility
If additional communication protocol overhead is added for localization, then localization functionality is improved, but network efficiency deteriorates
Solution Approach 1:
The patent enables the network to simultaneously perform channel estimation and time-of-arrival measurement using the same reference signals. This multi-functional approach allows localization functionality to be added without requiring separate protocol messages or additional overhead, as existing signaling resources are leveraged for dual purposes.
4Device complexity
If phase offset cancellation is not performed, then processing complexity is reduced, but localization accuracy deteriorates
Solution Approach 1:
The patent employs statistical estimation techniques that use feedback from multiple reference signal measurements to cancel phase offsets. By accumulating phase information across multiple subcarriers and applying estimation algorithms, the system removes the harmful effects of phase offsets while maintaining computational feasibility through efficient statistical processing.
Data Source
AI summary
A method for calculating a time-of-arrival of a multicarrier uplink signal includes: accessing a multicarrier reference signal including a subcarrier reference signal for each subcarrier frequency in a set of subcarrier frequencies; receiving the multicarrier uplink signal transmitted from a user device, the multicarrier uplink signal including a subcarrier uplink signal for each subcarrier frequency in the set of subcarrier frequencies; for each subcarrier frequency in the set of subcarrier frequencies, calculating a phase difference, in a set of phase differences, between the subcarrier reference signal for the subcarrier frequency and a subcarrier uplink signal for the subcarrier frequency; calculating a time-of-arrival of the multicarrier uplink signal at the transceiver based on the set of adjusted phase differences; and transmitting the time-of-arrival of the multicarrier uplink signal to a remote server.