Multicarrier Phase Localization Using Existing OFDM Signals
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Solution Overview
Problem
Existing radio frequency localization methods face challenges in achieving accurate localization of user devices without occupying additional bandwidth, requiring hardware modifications, or protocol changes, especially in communication networks like 4G and 5G.
Innovation Solution
A method utilizing multicarrier phase-based localization that calculates time-of-arrival (TOA) and time-differences-of-arrival (TDOA) by extracting phase information from subcarrier signals, adjusting for frequency-dependent phase offsets, and leveraging existing communication protocols like OFDM and 5G NRPPa/LTE/LPPe to enhance localization accuracy without additional bandwidth or hardware modifications.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional radio frequency localization methods are used, then hardware modifications and additional bandwidth are required, but this increases device complexity and network resource consumption
Solution Approach 1:
The system uses existing multicarrier communication signals (such as OFDM signals in 4G/5G networks) that are already being transmitted for data communication purposes. The localization function is achieved by extracting phase information from these existing signals without requiring separate dedicated localization signals, thus making the system self-serving and avoiding additional bandwidth consumption.
Solution Approach 2:
The multicarrier communication signals serve dual purposes: both data transmission and localization. By utilizing the same signal infrastructure for both communication and positioning functions, the system eliminates the need for separate hardware modifications and additional bandwidth allocation, achieving multi-functionality from a single signal system.
2Measurement precision
If phase information from multiple subcarriers is extracted and adjusted, then localization accuracy improves to within one meter, but calculation complexity increases
Solution Approach 1:
The system extracts phase information from multiple subcarriers within the multicarrier signal and applies frequency-dependent phase offset adjustments. By changing and optimizing the parameter selection (which subcarriers to use and how to adjust their phases), the system achieves high localization accuracy while managing calculation complexity through intelligent parameter management rather than brute-force processing.
Solution Approach 2:
The patent replaces traditional time-based measurement methods with phase-based measurements. By using phase information from frequency domain subcarriers instead of time domain signal arrivals, the system achieves higher accuracy and enables parallel processing of multiple frequency components, reducing overall computational burden despite the complexity of phase adjustments.
3Measurement precision
If frequency-dependent phase offsets are adjusted using calibration functions, then measurement accuracy improves, but system complexity and calibration requirements increase
Solution Approach 1:
The system performs calibration to determine frequency-dependent phase offsets in advance, before actual localization measurements are taken. By pre-characterizing the phase response of the receiver across different subcarrier frequencies and storing these calibration parameters, the system eliminates the need for real-time complex calculations during localization operations, thereby reducing operational complexity while maintaining high accuracy.
4Quantity of substance
If existing communication protocols like OFDM are utilized, then additional bandwidth occupation is avoided, but protocol adaptation complexity increases
Solution Approach 1:
The system leverages the existing multicarrier signal structure already present in 4G/5G communication protocols for data transmission. By extracting localization information from these existing signals without requiring separate dedicated positioning signals, the system avoids additional bandwidth occupation while the protocol adaptation is handled through software-based signal processing of the existing communication waveform.
Solution Approach 2:
The existing multicarrier communication protocol serves dual purposes: data communication and localization. The same OFDM signal structure, subcarrier frequencies, and transmission mechanisms are used for both communication and positioning functions, achieving universality and eliminating the need for separate protocol implementations.
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.