Secondary Node Positioning via Packet Interception
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Solution Overview
Problem
Current methods for positioning devices in wireless communications networks, such as RTT and one-way ToF measurements, face challenges due to non-deterministic processing times and limitations in transmission exchanges, which affect precision and accuracy.
Innovation Solution
A secondary node intercepts positioning data packets from a primary node and determines the transmitting time by subtracting the known time difference between the nodes' positions, allowing for relative synchronization without actual time synchronization, thereby reducing the number of transmissions required for device positioning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If RTT measurements are used for positioning, then the processing time can be accounted for, but the precision deteriorates due to non-deterministic processing time variations
Solution Approach 1:
A secondary node is introduced as an intermediary between the primary node and the device. The secondary node intercepts positioning data packets, determines transmitting time based on known position differences, and enables positioning without requiring the device to perform time synchronization or provide precise timing information. This mediator approach eliminates the need for direct timing measurements from the device while maintaining positioning reliability.
Solution Approach 2:
The system performs preliminary actions by having the secondary node determine the transmitting time of positioning data packets before the device responds. By pre-calculating the transmitting time based on the known time difference between primary and secondary node positions, the system eliminates the need for the device to process timing information, thereby avoiding non-deterministic processing time variations that would degrade precision.
2Measurement precision
If one-way ToF measurement is used for positioning, then processing time is excluded, but clock synchronization between node and device is required
Solution Approach 1:
The secondary node acts as a mediator that performs time synchronization indirectly. Instead of requiring the device to synchronize its clock with the primary node, the secondary node uses its known position relationship with the primary node to determine transmitting times. This eliminates the need for direct clock synchronization between the primary node and device while maintaining precise timing information for positioning.
Solution Approach 2:
The secondary node copies the positioning data packets from the primary node and processes them independently. By intercepting and replicating the positioning data packets, the secondary node can determine transmitting times without requiring the device to participate in time synchronization procedures, thereby simplifying the overall system complexity while maintaining measurement precision.
3Measurement precision
If multiple request-response signal exchanges are performed for positioning, then positioning accuracy improves, but the number of transmissions increases
Solution Approach 1:
The secondary node intercepts positioning data packets and determines transmitting times that can be used for positioning calculations. By having the secondary node perform these determinations, the system can reduce the number of direct transmissions between the primary node and device while still achieving accurate positioning, as the secondary node's timing information can be used for multiple positioning calculations.
Solution Approach 2:
The secondary node serves multiple functions: it intercepts positioning data packets, determines transmitting times, and enables positioning without requiring additional transmissions from the device. This multi-functional approach allows a single packet exchange to serve multiple positioning purposes, thereby improving transmission efficiency while maintaining positioning accuracy.
Data Source
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AI summary
A method performed by a secondary node (111, 112) for enabling positioning of a device (121) in a wireless communications network (100). First, the secondary node (111, 112) receives a positioning data packet from a primary node (110) to the device (121). The secondary node (111, 112) then determines the transmitting time of the positioning data packet based on the reception time of the positioning data packet in the secondary node (111, 112) and the position of the primary node (110) and the secondary node (111, 112). The secondary node (111, 112) also receives a request response from the device (121) to the primary node (110). The secondary node (111, 112) then enables positioning of the device (121) based on the determined transmitting time of the positioning data packet and the reception time of the received request response. A secondary node (111, 112) for enabling positioning of a device (121) in a wireless communications network (100) is also provided. Furthermore, a central node and a method therein for positioning a device (121) in a wireless communications network (100)) are also provided.