IAB Node Positioning via Location Server Collaboration
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Solution Overview
Problem
Wireless communication systems face challenges in determining the position of base stations with unknown locations, particularly mobile Integrated Access and Backhaul (IAB) nodes, which are essential for accurate user equipment (UE) positioning but often lack GPS receivers or have inaccurate site surveys, rendering them unreliable for positioning services.
Innovation Solution
An Integrated Access Backhaul (IAB) node with a mobile terminated (MT) function and distributed unit (DU) function engages in positioning sessions with multiple base stations and user equipment (UEs) to send or receive reference signals, allowing a location server to determine its position using positioning measurements, and provides mobility indications to exclude mobile IAB nodes from UE positioning calculations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If IAB nodes are deployed to extend network coverage and support mobile backhaul, then network flexibility and coverage are improved, but positioning accuracy deteriorates because IAB nodes lack GPS receivers or have inaccurate site surveys
Solution Approach 1:
The patent introduces location servers as intermediary entities that collect positioning measurements from multiple IAB nodes and compute their positions indirectly. Instead of requiring each IAB node to have direct GPS capability, the location server acts as a mediator that aggregates measurement data from multiple sources (IAB nodes, base stations, UEs) and determines positions through collaborative positioning algorithms, thereby resolving the contradiction between network flexibility and positioning accuracy
Solution Approach 2:
The patent enables IAB nodes to perform multiple functions: they serve as both access points for UEs and as positioning measurement sources for other IAB nodes and base stations. The MT and DU functions of IAB nodes are utilized universally for both communication and positioning purposes, allowing the same infrastructure to support both network extension and positioning accuracy requirements
2Adaptability or versatility
If mobile IAB nodes are used to provide dynamic network coverage, then network adaptability is improved, but reliability of positioning information deteriorates due to mobility rendering previously known locations invalid
Solution Approach 1:
The patent implements continuous feedback loops where IAB nodes periodically transmit positioning measurements to location servers, which compute updated positions and feed back this information to the network. This feedback mechanism ensures that positioning information remains current and reliable even for mobile IAB nodes, as the system continuously updates location data based on recent measurements rather than relying on stale stored information
Solution Approach 2:
The patent transitions from static positioning assumptions to dynamic positioning by enabling IAB nodes to continuously update their position measurements and by having the location server compute real-time positions based on current measurements. The system adapts to mobility by making positioning a dynamic, ongoing process rather than a one-time static determination, allowing the network to track and utilize the changing positions of mobile IAB nodes
3Area of stationary object
If IAB nodes participate in UE positioning calculations, then positioning coverage is improved, but accuracy deteriorates when IAB node positions are unknown or inaccurate
Solution Approach 1:
The patent performs preliminary positioning of IAB nodes before they are used for UE positioning calculations. The location server first determines the positions of IAB nodes using measurements from base stations and other IAB nodes, storing this preliminary position information. Only after this preliminary positioning is complete are the IAB nodes incorporated into UE positioning calculations, ensuring that the positioning coverage is extended while maintaining accuracy by using pre-validated position data
Data Source
AI summary
An integrated access backhaul (IAB) node with an unknown position may use the mobile terminated (MT) function to send or receive reference signals to or from multiple base stations in one or more positioning sessions for positioning of the IAB node. The distributed unit (DU) function may be used additionally, or alternatively, to send or receive reference signals to or from multiple nodes, e.g., user equipments (UEs) or MT functions of downstream IAB nodes. Positioning measurements from the reference signals may be sent to a location server, which may determine the position of the IAB node. The location server may further receive an indication of the mobility of the IAB node, which may be used for positioning of UEs, e.g., by excluding information about a mobile IAB node during positioning.