Uplink Positioning via Inter-Cell Interference Coordination
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Solution Overview
Problem
Current positioning techniques in LTE systems, such as OTDOA, A-GNSS, and E-CID, face limitations in accuracy and failure rates due to high intercell interference in next-generation wireless communication systems, particularly in urban environments where GPS signal penetration is poor.
Innovation Solution
A method where a serving eNodeB shares positioning scheduling information with cooperating eNodeBs to mitigate interference by re-allocating uplink transmission resources, allowing for high accuracy positioning without an adjunct measurement system, even in scenarios with high bandwidth reuse across adjacent cells.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If uplink-based TOA or TDOA positioning techniques are used in next-generation systems with high bandwidth reuse, then positioning accuracy can be improved, but intercell interference increases significantly causing unacceptably high failure rates
Solution Approach 1:
The system performs preliminary interference coordination by sharing positioning scheduling information between eNodeBs before the positioning signal transmission occurs. The serving eNodeB provides information about the positioning signal's time, frequency, and other parameters to neighboring eNodeBs in advance, allowing them to proactively avoid scheduling conflicting uplink transmissions from other UEs that would cause interference.
Solution Approach 2:
The patent introduces an intermediary mechanism where the serving eNodeB acts as a coordinator that collects positioning scheduling information and distributes it to neighboring eNodeBs. This intermediary information exchange enables the network to coordinate interference avoidance without requiring direct communication between all pairs of eNodeBs, reducing signaling overhead while achieving reliable interference mitigation.
2Productivity
If positioning signals are transmitted in high-traffic scenarios with bandwidth reuse across adjacent cells, then network resource utilization improves, but signal-to-interference ratio decreases making accurate positioning difficult
Solution Approach 1:
The system applies local quality by providing differentiated treatment to positioning signals versus regular data transmissions. Neighboring eNodeBs receive specific positioning scheduling information and apply targeted interference avoidance measures only for the positioning signal time-frequency resources, while maintaining normal bandwidth reuse for other uplink transmissions. This ensures high signal-to-interference ratio for positioning without sacrificing overall network resource utilization.
3Ease of manufacture
If GPS signal reception is used for positioning, then positioning can be implemented with simple mobile unit equipment, but GPS signal penetration is poor in urban environments leading to high failure rates
Solution Approach 1:
The patent replaces the GPS satellite-based positioning mechanism with a terrestrial network-based positioning system using uplink TOA or TDOA measurements. Instead of relying on line-of-sight GPS signals from space, the system uses the existing cellular network infrastructure and uplink transmissions from the UE to neighboring eNodeBs for positioning, eliminating the signal penetration problem in urban environments while keeping the UE equipment simple.
Data Source
AI summary
Methods, devices and systems for determining positions of user equipments (UEs) based on uplink position signals are described. Cooperating base stations measure received positioning signals and report measurements to serving base stations. Cooperating base stations can also adapt resource allocation to mitigate interference on the uplink to positioning signals. Cooperation between base stations can be coordinated via inter-base station links, e.g., X2 interfaces in LTE systems.