Dedicated Measurement Gaps for Dense PRS RSTD Accuracy
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Solution Overview
Problem
Existing methods for User Equipment (UE) location determination, particularly for enhanced Machine Type Communication (eMTC) and Further enhanced Machine Type Communication (FeMTC) UEs, face challenges in providing accurate location services in environments with dense PRS configurations and increased PRS transmission frequencies, leading to potential data loss.
Innovation Solution
The method involves a UE requesting dedicated gaps with a specified configuration for performing Reference Signal Time Difference (RSTD) measurements. The UE transmits a dedicated gap request to a Base Station (BS), which responds with a message containing the dedicated gap configuration. This allows the UE to perform PRS measurements during dedicated gaps, which can be longer or more frequent than conventional measurement gaps, without risking data loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional measurement gaps are used for RSTD measurements, then the UE can perform positioning measurements, but the measurement gaps are insufficient in length and frequency for dense PRS configurations, leading to potential data loss
Solution Approach 1:
The patent implements dynamic measurement gap configuration where the gap length and frequency are adjusted based on the specific PRS configuration and positioning requirements. The network can configure different gap patterns (e.g., gap pattern 0 with 6ms length, gap pattern 1 with 10ms length) and the UE can request specific gap configurations suitable for dense PRS scenarios, making the measurement gap system flexible and adaptive rather than fixed.
Solution Approach 2:
The patent changes the parameters of measurement gaps (length, frequency, pattern) to match the dense PRS configuration requirements. By modifying the gap duration from conventional 6ms to extended 10ms or longer, and adjusting the gap frequency to align with increased PRS transmission frequencies, the system ensures complete PRS signal capture without data loss while maintaining measurement accuracy.
2Measurement precision
If measurement gaps are extended or increased in frequency to support dense PRS configurations, then RSTD measurement accuracy improves, but network resource overhead and complexity increase
Solution Approach 1:
The patent employs preliminary configuration where the network pre-defines multiple measurement gap patterns with different characteristics (gap pattern 0, 1, 2, etc. with varying lengths and frequencies). The UE can indicate its preferred pattern based on positioning requirements, and the network configures the appropriate pattern in advance before actual measurements begin, avoiding complex real-time adjustments during measurement operations.
3Measurement precision
If dedicated gaps are configured for eMTC/FeMTC UEs to perform RSTD measurements, then positioning accuracy in dense PRS environments improves, but the configuration process becomes more complex
Solution Approach 1:
The patent implements a self-service mechanism where the UE autonomously determines its positioning requirements and sends a measurement gap indication to the network, requesting specific gap patterns suitable for its needs. The network then configures the appropriate dedicated gaps based on the UE's indication, allowing the UE to actively participate in its own measurement configuration rather than passively receiving generic configurations.
Data Source
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AI summary
Disclosed embodiments facilitate UE location determination in systems with dense PRS configurations, reduced PRS periodicity, frequency hopping, and involving UE inter-frequency measurements. The techniques may be applied to Bandwidth reduced-Low complexity (BL) UEs, or enhanced Machine Type Communication (eMTC) UEs or Further enhanced MTC (FeMTC) UEs and/or in LTE-M systems. A method on a UE may comprise: receiving a Reference Signal Time Difference (RSTD) measurement request; transmitting, in response to the RSTD measurement request, a dedicated gap request comprising a requested configuration of dedicated gaps; and receiving, in response to the dedicated gap request, a message comprising a dedicated gap configuration. The dedicated gap request may comprise a request for dedicated measurement gaps and the message may comprise a dedicated measurement gap configuration. In some embodiments, the dedicated gap request may comprise a request for dedicated autonomous gaps and the message may comprise a dedicated autonomous gap configuration.