RSTD Quantization for LTE Positioning Accuracy
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Solution Overview
Problem
Current RSTD measurement reporting in LTE positioning systems has limited resolution, restricting positioning accuracy due to quantization limitations and auto-correlation issues with PRS signals, which can be improved by enhancing the quantization method and signaling protocols.
Innovation Solution
The proposed solution involves an Enhanced RSTD Quantization Method (E-QM) that dynamically quantizes RSTD measurements using Network Assisted and UE-Assisted Quantization Information, allowing for optimized quantization functions based on measurement properties and scenarios, thereby improving the efficiency and accuracy of RSTD reporting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If current RSTD quantization method with fixed resolution is used, then device complexity is reduced and ease of operation is improved, but measurement precision and positioning accuracy deteriorate due to limited resolution (1 Ts or 5 Ts)
Solution Approach 1:
The patent implements dynamic quantization where the quantization resolution is adaptively adjusted based on measured signal properties. The UE determines quantization parameters (resolution, range, number of bits) dynamically according to the specific measurement scenario, transitioning from fixed to variable quantization characteristics to optimize precision while managing complexity.
Solution Approach 2:
The patent changes the quantization parameters (resolution, range, number of bits) based on measured signal conditions. The UE selects appropriate quantization parameters from predefined sets or determines them dynamically, allowing the system to adapt quantization characteristics to match measurement requirements, thereby improving precision without excessive complexity increase.
2Measurement precision
If finer RSTD measurement reporting resolution is implemented, then positioning accuracy is improved, but loss of information is reduced and signaling overhead increases
Solution Approach 1:
The patent employs adaptive parameter selection where the UE determines optimal quantization parameters (resolution, range, number of bits) based on measured signal properties. This allows the system to use finer resolution when needed for high accuracy while coarser resolution can be used when sufficient, thereby minimizing information loss while achieving required positioning accuracy.
Solution Approach 2:
The patent applies quantization at different resolutions selectively - using finer quantization only when measurement conditions require it, rather than uniformly applying high-resolution quantization to all measurements. This partial application of fine quantization reduces overall information loss while maintaining positioning accuracy where critical.
3Measurement precision
If dynamic quantization with Network Assisted and UE-Assisted Quantization Information is used, then measurement precision and positioning accuracy are improved, but device complexity and signaling overhead increase
Solution Approach 1:
The patent divides the quantization management function into two segments: Network Assisted Quantization Information (providing configuration and constraints from the network) and UE-Assisted Quantization Information (providing measured signal properties and selected parameters from UE). This segmentation allows complex dynamic quantization to be managed through coordinated but separate functions, reducing overall system complexity while maintaining precision.
Solution Approach 2:
The patent introduces quantization information messages as intermediaries between the UE and network. These messages carry quantization parameters and constraints, serving as a mediator that enables dynamic quantization without requiring complex direct coordination. The intermediary structure simplifies the interaction while enabling precise measurement reporting.
Data Source
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AI summary
The disclosed embodiments herein relate to a method performed by a UE (110); a UE (110), a method performed by a location server (120) and a location server (120) and computer programs respectively. The method performed by the UE (110) comprises: receiving (401) from a location server NetWork assisted Reference Signal Time Difference, RSTD, Quantization Information, NW-QI; performing (402) RSTD measurements by measuring or estimating a Time Of Arrival, TOA, of a Positioning Reference Signal, PRS, from respective base station of a plurality of base stations; encoding (403) the RSTD measurements by employing a Enhanced RSTD Quantization Method, E- QM, or by using the NW-QI while encoding the RSTD measurements; and sending (404) UE assisted RSTD Quantization Information, UE-QI, to the location server, the UE-QI including the encoded RSTD measurements.