RTT Positioning Resource Scheduling for Beamformed mmWave Links
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Solution Overview
Problem
Propagation loss and timing inaccuracies in mmW band and MIMO systems affect the precision of position estimation, particularly when beamforming results in longer propagation delays due to non-line-of-sight paths.
Innovation Solution
Implementing a network node and user equipment exchange of round trip time (RTT) signals using downlink and uplink positioning reference signals, with a quasi-colocation relationship, to accurately determine the RTT between the network node and user equipment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If beamforming is used to extend RF signal coverage in mmW band systems, then signal coverage and data rate are improved, but propagation delay increases due to non-line-of-sight paths
Solution Approach 1:
The patent segments the positioning measurement process into multiple independent RTT measurements using different beams. Instead of relying on a single beam path, the system performs separate timing measurements for each beam direction, allowing the UE to identify and select measurements from optimal paths (e.g., line-of-sight) while excluding measurements from suboptimal paths (e.g., reflected or diffracted paths).
Solution Approach 2:
The patent implements dynamic beam selection and measurement optimization where the UE adapts its positioning strategy based on real-time channel conditions. The system dynamically identifies which beams provide the most accurate timing measurements by analyzing signal characteristics such as timing advance values and signal strength, and adjusts the set of beams used for positioning accordingly.
2Reliability
If multiple beams are used for RTT measurements to improve positioning accuracy, then measurement reliability is improved, but device complexity and processing overhead increase
Solution Approach 1:
The patent applies partial action by selecting and processing only a subset of beams that are most relevant for positioning accuracy. Instead of uniformly processing all transmitted beams, the system identifies and focuses computational resources on beams that provide the most reliable timing measurements, based on criteria such as signal strength, timing advance consistency, and path characteristics. This reduces processing overhead while maintaining positioning reliability.
Solution Approach 2:
The patent performs preliminary beam evaluation and selection before final positioning calculation. The UE pre-processes received beams to identify which ones are suitable for RTT measurement based on initial signal quality assessments and timing characteristics. This preliminary filtering reduces the number of beams that require detailed processing, thereby reducing overall device complexity while ensuring that only high-quality measurements are used for positioning.
3Adaptability or versatility
If traditional timing measurement methods are used in MIMO systems, then system compatibility is maintained, but position estimation precision deteriorates due to multipath propagation
Solution Approach 1:
The patent implements feedback mechanisms where the UE provides timing advance information and measurement results back to the network. The network uses this feedback to refine beam selection and adjust positioning parameters. This closed-loop approach allows the system to learn from measurement outcomes and improve positioning precision over time while maintaining compatibility with existing MIMO operations.
Solution Approach 2:
The patent changes key positioning parameters such as the set of beams used for measurement, the timing reference points, and the processing weights assigned to different measurement results. By dynamically adjusting these parameters based on channel conditions and beam characteristics, the system achieves higher positioning precision in MIMO environments while maintaining compatibility with existing protocols and procedures.
Data Source
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AI summary
Disclosed are techniques for scheduling uplink (UL) and downlink (DL) physical layer resources for a serving node and a user equipment (UE) for round trip time (RTT) and observed time difference of arrival (OTDOA) based positioning. In an aspect, a serving node and/or a network entity configure the UL and DL physical layer resources, and inform the UE. A network node transmits RTT measurement (RTTM) signal to the UE and receives RTT response (RTTR) signals from the UE. The network node measures the times the RTTM signals are transmitted and the times the RTTR signals are received. The UE provides to serving node processing times indicating a duration between the UE receiving the RTTM signals and the UE transmitting the RTTR signals. The RTTs are calculated from the times measured by the network node and the processing times provided by the UE.