Multi-Cell Positioning via Serving Cell Relay
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Solution Overview
Problem
In multi-cell RTT based positioning methods, the hearability of uplink signals is challenged due to low transmit power and link budget differences between downlink and uplink signals, especially when proper beam management is lacking between user equipment (UE) and neighbor cells, leading to decreased positioning accuracy.
Innovation Solution
The method involves a serving network device acting as a relay for RTT estimation between a terminal device and a neighboring network device, transmitting reference signals to determine time differences, which are then used by a location server to estimate positioning information without requiring the terminal device to transmit directly to the neighbor cell, thereby increasing the number of hearable network devices and improving accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the terminal device transmits uplink reference signals directly to the neighbor cell for RTT estimation, then the positioning accuracy can be improved, but the hearability of the uplink signal decreases due to low transmit power and link budget differences
Solution Approach 1:
The serving cell acts as an intermediary to relay reference signals between the terminal device and the neighbor cell. The serving cell transmits downlink reference signals to the terminal device and receives uplink reference signals from the terminal device, then forwards them to the neighbor cell for RTT estimation, enabling accurate positioning without requiring direct uplink transmission from the terminal to the distant neighbor cell
Solution Approach 2:
The patent introduces a new dimension to the RTT estimation process by involving the serving cell as an active participant in the signal exchange. Instead of a direct terminal-to-neighbor cell measurement, the measurement path is extended through the serving cell, adding an intermediate measurement point that improves signal hearability while maintaining positioning accuracy
2Measurement precision
If beam management is implemented between the terminal device and the neighbor cell to improve hearability, then the positioning accuracy improves, but the device complexity and signaling overhead increase
Solution Approach 1:
The patent extracts the beam management function from the terminal device and relocates it to the network side (serving cell and/or neighbor cell). The network devices handle beamforming and beam management for reference signal transmission and reception, eliminating the need for complex beam management at the terminal device while still achieving improved hearability and positioning accuracy
3Measurement precision
If the terminal device transmits additional uplink signals to improve neighbor cell hearability, then the positioning accuracy improves, but the use of energy and device complexity increase
Solution Approach 1:
The patent makes the existing uplink reference signals serve multiple functions: they are used both for normal uplink communication and for RTT estimation at the neighbor cell. By configuring the serving cell to forward these existing signals to the neighbor cell, the patent achieves improved positioning accuracy without requiring additional dedicated uplink transmissions from the terminal device
Data Source
AI summary
Embodiments of the present disclosure relate to methods, devices, apparatuses and computer readable storage media for multi-cell positioning. In example embodiments, a method is provided. The method comprises transmitting, from a first network device, a first reference signal to a terminal device served by a second network device. The method further comprises receiving a second reference signal from the second network device. The method further comprises determining a first time difference between a time at which the first RS is transmitted and a time at which the second reference signal is received. In addition, the method comprises transmitting information on the first time difference to a location server. As such, the location server can determine positioning information about the terminal device.