PRS Muting Patterns for LTE Positioning Interference
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Solution Overview
Problem
Current positioning solutions in LTE networks face challenges such as poor hearability of PRS, inflexible muting patterns, lack of interference coordination, and incompatibility with distributed antenna systems and LTE Advanced deployment scenarios, leading to suboptimal positioning accuracy and increased UE complexity.
Innovation Solution
The method involves dynamically determining muting patterns for PRS transmission in LTE networks, allowing cells to transmit or mute PRS at different intervals, and providing assistance information to UEs, enabling optimal PRS orthogonality and interference minimization through cell grouping and signaling enhancements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If PRS are transmitted continuously to improve positioning accuracy, then positioning accuracy is improved, but interference between cells increases
Solution Approach 1:
The patent applies periodic action by implementing discontinuous PRS transmission with muting patterns. Cells transmit PRS in specific subframes according to a periodic pattern rather than continuously, which reduces interference between cells while maintaining positioning accuracy. The muting pattern configures which cells transmit PRS in which subframes, creating a periodic transmission schedule that balances coverage and interference reduction.
Solution Approach 2:
The patent implements dynamics by making PRS transmission configurable and adaptable through muting patterns. The transmission behavior is not fixed but can be dynamically adjusted based on network conditions, cell geometry, and positioning requirements. This allows the system to optimize the balance between positioning accuracy and interference reduction adaptively.
2Object-generated harmful factors
If muting patterns are made flexible to reduce interference, then interference coordination is improved, but device complexity increases
Solution Approach 1:
The patent applies preliminary action by providing muting pattern information to the UE in advance through assistance data. The UE receives pre-configured information about which cells will transmit PRS and when, allowing it to prepare for measurements efficiently. This preliminary provision of information reduces the computational complexity during actual positioning operations.
Solution Approach 2:
The patent uses an intermediary approach by introducing a standardized muting pattern configuration mechanism that mediates between network interference coordination requirements and UE complexity. The muting pattern acts as an intermediary parameter that the network configures to reduce interference while the UE simply follows the pre-configured pattern without complex real-time decisions.
3Object-generated harmful factors
If PRS transmission is made discontinuous to reduce interference, then interference is reduced, but hearability of PRS deteriorates
Solution Approach 1:
The patent applies local quality by making PRS transmission cell-specific through muting patterns. Different cells have different transmission patterns tailored to their local interference conditions and geometry. This allows cells in different locations to transmit PRS at different times, reducing overall interference while ensuring that each cell maintains sufficient hearability in its local area.
Solution Approach 2:
The patent implements continuity of useful action by ensuring that while individual cells mute PRS transmission at times, the network as a whole maintains continuous positioning capability. The muting patterns are coordinated so that positioning measurements can continue using PRS from other cells during muted periods, maintaining the continuity of the positioning service.
Data Source
AI summary
GPS and A-GPS based positioning methods can be used to determine UE locations to enable location based services to be provided. However, if a UE does not have such receivers or the wireless network is not able to provide assistance, these methods will not be applicable. An alternative is to use OTDOA measurements using positioning reference signals transmitted by cells of the network. By optimizing the set of cells transmitting their positioning reference signals on different positioning occasions and properly configuring the muting patterns, interference can be minimized and the UE location can be readily determined.