Adaptive PRS for Indoor Location Accuracy
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Solution Overview
Problem
Existing indoor positioning methods, such as OTDOA in LTE networks, face challenges in achieving accurate location determination for user equipment (UE) indoors due to signal attenuation and multipath issues, which affects emergency services and other location-based applications.
Innovation Solution
Adaptive Positioning Reference Signal (PRS) transmissions are enhanced by switching to an emergency PRS mode, which increases bandwidth, frequency, and coding, and adjusts transmission schedules to improve signal acquisition and measurement accuracy for UE positioning, particularly in indoor environments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional PRS transmissions are used for indoor positioning, then network resource consumption is reduced, but positioning accuracy deteriorates due to signal attenuation and multipath issues
Solution Approach 1:
The system dynamically switches between traditional PRS mode and emergency PRS mode based on positioning requirements. In emergency mode, PRS transmissions are activated with enhanced parameters (higher bandwidth, increased power, more frequent transmissions) to improve indoor positioning accuracy when needed, while returning to traditional mode during normal operations to conserve network resources.
Solution Approach 2:
The patent changes key transmission parameters of PRS signals when switching to emergency mode, including increasing bandwidth allocation, adjusting transmission power levels, and modifying transmission frequency. These parameter changes enable the system to overcome signal attenuation and multipath effects in indoor environments, achieving better positioning accuracy without permanently increasing network resource consumption.
2Measurement precision
If PRS transmission frequency is increased to improve indoor signal acquisition, then positioning accuracy improves, but network interference increases
Solution Approach 1:
The system implements periodic PRS transmissions with optimized timing patterns. During emergency positioning mode, PRS signals are transmitted more frequently with specific periodicity to enhance signal acquisition accuracy for indoor UEs. The periodic transmission schedule is carefully designed to distribute interference over time and frequency resources, preventing continuous high-level interference while maintaining adequate signal acquisition capability.
Solution Approach 2:
The network pre-configures multiple PRS transmission schedules with different parameters (bandwidth, power, frequency) and selectively activates appropriate schedules based on positioning requirements. This preliminary preparation allows the system to quickly switch to high-frequency transmissions when indoor positioning is needed, while maintaining lower transmission frequencies during normal operations to minimize network interference.
Data Source
AI summary
Methods and systems for adapting positioning reference signal (PRS) transmissions are disclosed. A server receives a request to support an emergency call associated with a user equipment (UE) and sends a first PRS schedule to a first base station, the first PRS schedule configured to enable the first base station to switch to a first emergency PRS mode and to transmit PRS signals according to the first PRS schedule. The base station establishes a PRS schedule, switches to an emergency PRS mode, and transmits PRS signals in accordance with the PRS schedule. A UE initiates an emergency call, receives positioning assistance data from a server, performs terrestrial radio location positioning measurements based on the received positioning assistance data, and provides the terrestrial radio location positioning measurements or a location computed from these measurements to the server.