UL-PRS Scheduling Across DRX OFF Time for Low-Power 5G Positioning
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Solution Overview
Problem
The 5G wireless communication systems face challenges in optimizing the interaction between uplink positioning reference signals (UL-PRS), discontinuous reception (DRX), and wakeup signals (WUS) to enhance spectral efficiency and reduce latency, particularly in scenarios involving multiple carrier frequencies and beamforming techniques.
Innovation Solution
The proposed solution involves configuring the UE's DRX cycles to align with UL-PRS and WUS operations, ensuring efficient power management and reduced latency by optimizing the interaction between these signals, thereby enhancing the UE's power efficiency and reducing unnecessary wake-up times.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the UE wakes up frequently to monitor for UL-PRS transmission opportunities, then positioning accuracy is improved, but power consumption increases
Solution Approach 1:
The network configures the UE with advance information about upcoming UL-PRS transmission opportunities, including timing and frequency resources. This allows the UE to enter DRX mode and wake up only at predetermined moments to transmit positioning signals, rather than continuously monitoring, thereby reducing power consumption while maintaining positioning accuracy
Solution Approach 2:
The system implements periodic UL-PRS transmission opportunities aligned with DRX cycles. The UE transmits positioning reference signals at regular intervals configured by the network, ensuring positioning accuracy is maintained while the UE can sleep between periodic transmission opportunities, thus reducing overall power consumption
2Measurement precision
If the UE transmits UL-PRS frequently, then positioning accuracy is improved, but spectral efficiency deteriorates
Solution Approach 1:
The network configures UE-specific UL-PRS transmission parameters including frequency resources, time resources, and beam directions. Each UE transmits positioning signals on locally optimized resources tailored to its positioning requirements, rather than all UEs using the same resources, thereby improving spectral efficiency while maintaining positioning accuracy
Solution Approach 2:
The system divides the uplink spectrum into multiple frequency resources and time resources for UL-PRS transmissions. Different UEs are assigned different resource segments, allowing simultaneous positioning transmissions without interference, thus improving overall spectral efficiency while each UE maintains accurate positioning through dedicated resource allocation
3Loss of time
If DRX cycle length is shortened, then latency is reduced, but power consumption increases
Solution Approach 1:
The network provides advance configuration information about UL-PRS transmission opportunities, including multiple future occasions. The UE can then extend its DRX sleep periods knowing exactly when to wake up for positioning transmissions, reducing latency by having pre-known opportunities while minimizing power consumption through longer sleep intervals
Solution Approach 2:
The system dynamically adjusts DRX cycle lengths and UL-PRS transmission opportunities based on UE mobility state, positioning requirements, and network conditions. For high-mobility UEs or those requiring frequent positioning, shorter DRX cycles are configured; for stationary UEs, longer cycles reduce power consumption, thereby dynamically optimizing the latency-power tradeoff
Data Source
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AI summary
Disclosed are techniques for wireless communication. In an aspect, a user equipment (UE) configured to operate in discontinuous reception (DRX) mode switches to DRX active time of a DRX cycle of the DRX mode, and transmits one or more uplink positioning reference signal (UL-PRS) resources of an UL-PRS occasion based on the UL-PRS occasion at least partially overlapping DRX OFF time of the DRX cycle after the DRX active time.