Idle Mode UE Positioning via OTDOA Reference Signals
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Solution Overview
Problem
In wireless networks, user equipment (UE) in RRC_idle or RRC_inactive states require significant power consumption and signaling overhead to perform positioning measurements, as they need to transition to RRC_connected mode for OTDOA calculations, which is inefficient for IoT devices with low power consumption requirements.
Innovation Solution
The method allows UE to perform OTDOA positioning measurements and reporting while remaining in RRC_idle or RRC_inactive mode by using a paging message with data transmission schemes like early data transmission (EDT) or small data transmission (SDT), eliminating the need for state changes and reducing signaling overhead.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If UE transitions to RRC_connected mode to perform positioning measurements, then positioning accuracy is improved, but power consumption increases
Solution Approach 1:
The network pre-configures positioning reference signals (PRS) and assistance information while the UE is in idle or inactive state, so that when positioning is needed, the UE can perform measurements immediately without needing to transition to connected state, thus maintaining positioning accuracy while reducing power consumption
Solution Approach 2:
The patent uses positioning reference signals (PRS) that are transmitted periodically and can be received and measured by the UE in idle state, effectively creating a copy of the positioning functionality that doesn't require full RRC connection establishment
2Measurement precision
If UE transitions to RRC_connected mode for positioning measurements, then positioning capability is improved, but signaling overhead increases
Solution Approach 1:
The patent extracts the essential positioning measurement functionality from the full RRC connection establishment process, allowing the UE to perform OTDOA measurements and report results while remaining in idle or inactive state, thereby eliminating the signaling overhead associated with state transitions while maintaining positioning capability
Solution Approach 2:
Assistance information including PRS configuration, neighbor cell lists, and timing advance values are provided to the UE in advance while it is in idle or inactive state, enabling the UE to perform positioning measurements without needing to establish a full RRC connection, thus reducing signaling overhead
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach decreases power consumption and signaling overhead, enabling IoT devices to perform positioning without entering the RRC_connected state, thus reducing power usage and network resource requirements.
Implementation Method 1
timing measurements are made at a UE and then reported to a location server (LS) for a positioning calculation... time of arrival (TOA) or time difference of arrival (TDOA) estimates are used to determine the distance between the transmitting and receiving nodes, based on the known speed of light
Data Source
AI summary
A method includes receiving positioning configuration information from a base station or location server while in an RRC_connected mode; transitioning to an RRC_idle or RRC_inactive mode, while saving the positioning configuration information; receiving a reference signal for positioning from the base station; performing positioning measurements, while in the RRC_idle or RRC_inactive mode; and sending a location report to the base station or location server while remaining in the RRC_idle or RRC_inactive mode. A related method includes sending positioning configuration information to a user equipment in an RRC_connected mode; sending the user equipment to RRC_idle or RRC_inactive mode by an RRC suspend procedure; sending a reference signal for positioning to the user equipment; receiving a location report from the user equipment in the RRC_idle or RRC_inactive mode; and forwarding the location report from the user equipment to a location server.