Downlink PRS Phase Difference for Wireless Distance Measurement
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Solution Overview
Problem
Current wireless communication systems face inefficiencies in measuring distance between a terminal and a base station, particularly when the terminal is moving, as they require continuous transmission and reception of positioning reference signals (PRS) to accurately calculate the changing distance, leading to increased overhead.
Innovation Solution
A method where a terminal receives a downlink PRS with sinusoidal components of different angular frequencies, acquires the phase difference, and transmits uplink PRSs indicating this phase difference without receiving additional downlink PRSs, allowing for distance measurement between the terminal and base station even when the terminal has changed location, thereby reducing the need for continuous PRS transmission and reception.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If continuous downlink PRS transmission and reception is performed to accurately measure changing distance when terminal is moving, then measurement precision is improved, but overhead increases
Solution Approach 1:
The terminal acquires and stores phase difference information from downlink PRS in advance. When needing to measure distance, it uses this pre-acquired phase difference information to calculate distance without requiring fresh downlink PRS transmission, thus reducing overhead while maintaining measurement capability.
Solution Approach 2:
The terminal transmits uplink PRS that contains copied phase difference information obtained from downlink PRS. This copied information allows the base station to measure distance without requiring the terminal to continuously receive and retransmit fresh downlink PRS, reducing overall system overhead.
2Measurement precision
If additional downlink PRS is received for distance measurement when terminal moves to changed location, then measurement precision is improved, but use of energy increases
Solution Approach 1:
The terminal performs downlink PRS reception and phase difference acquisition in advance, storing this information for later use. When the terminal moves and needs distance measurement, it utilizes the pre-acquired phase difference information combined with uplink PRS transmission, avoiding the need for additional downlink PRS reception and thus conserving energy.
3Reliability
If continuous PRS transmission and reception is performed to measure distance at changed location, then reliability is improved, but device complexity increases
Solution Approach 1:
The terminal acquires phase difference information from downlink PRS in advance and stores it. When distance measurement is needed at a new location, it uses this pre-acquired information combined with uplink PRS transmission, simplifying the device operations while maintaining reliable distance measurement capability.
Solution Approach 2:
The terminal transmits uplink PRS containing copied phase difference information. This approach allows the base station to perform distance measurement without requiring complex continuous downlink PRS transmission and reception protocols, thereby reducing device complexity while maintaining measurement reliability.
Data Source
AI summary
A method whereby a user equipment transmits/receives a reference signal for distance measurement in a wireless communication system according to an embodiment of the present invention comprises: a step of receiving, from a base station, a downlink (DL) positioning reference signal (PRS) including sinusoidal components of different angular frequencies; a step of acquiring a phase difference between the sinusoidal components of the DL PRS; a step of transmitting a first uplink (UL) PRS indicating the phase difference, so as to measure a first distance between the user equipment and the base station at a first point of time; and a step of transmitting a second UL PRS so as to measure a second distance between the user equipment, the position of which has changed after the first point of time, and the base station, wherein the user equipment may configure the same phase difference, acquired via the DL PRS before the first point of time, for the second UL PRS, without receiving an additional DL PRS for measuring the second distance. The user equipment is capable of communicating with at least one of another user equipment, a user equipment related to an autonomous driving vehicle, the base station or a network.