Sidelink LPP Transport for Out-of-Coverage UE Positioning
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Solution Overview
Problem
Existing wireless communication networks face challenges in determining the geographical position of user equipment (UE) when UEs are out of coverage, as the Long Term Evolution Positioning Protocol (LPP) cannot be used without a connection to the wireless communication network.
Innovation Solution
Enhancements to the sidelink protocol stack are introduced to enable LPP transport over PC5-RRC, PC5-S, and Packet Data Convergence Protocol (PDCP) interfaces, supporting capability transfer, assistance data transfer, and location information transfer between UEs over sidelink.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If LPP is used for positioning, then positioning functionality is provided, but it requires a connection to the wireless communication network which is not available when UEs are out of coverage
Solution Approach 1:
The patent introduces a positioning server as an intermediary entity that enables LPP positioning functionality to operate between UEs even when direct network connection is unavailable. The positioning server mediates the positioning protocol exchange, allowing UEs to perform positioning operations through the server's coordination rather than requiring direct Uu interface connectivity.
Solution Approach 2:
The patent extends the positioning architecture from a traditional two-dimensional UE-to-network connection model to a three-dimensional UE-to-positioning-server-to-UE communication path. This dimensional expansion allows positioning functionality to persist in out-of-coverage scenarios by routing messages through the positioning server rather than requiring direct network attachment.
2Adaptability or versatility
If sidelink protocol stack is enhanced to support LPP, then positioning over sidelink is enabled, but protocol complexity increases
Solution Approach 1:
The patent makes the sidelink protocol stack universal by enabling it to handle both traditional sidelink communications and LPP positioning protocols through the same infrastructure. The PC5 interface and existing sidelink mechanisms are enhanced to serve dual purposes: general V2X communication and positioning protocol exchange, eliminating the need for separate dedicated positioning infrastructure.
Solution Approach 2:
The patent reuses and adapts existing sidelink protocol mechanisms (PC5-RRC, PC5-S, PDCP) to carry LPP messages, rather than creating entirely new positioning protocols. By copying and repurposing existing protocol elements, the solution avoids the complexity of designing a completely new positioning infrastructure from scratch.
3Adaptability or versatility
If LPP messages are transported over PC5-RRC, PC5-S, and PDCP, then positioning messages can be exchanged between UEs out of coverage, but message transmission reliability may be affected
Solution Approach 1:
The patent implements feedback mechanisms within the LPP protocol exchange where UEs confirm receipt and processing of positioning messages. The positioning server receives feedback from UEs about message delivery status, enabling it to retransmit or adjust messaging strategies to ensure reliable positioning data exchange even over the less reliable sidelink interface.
Solution Approach 2:
The patent prepares for potential message transmission failures by implementing error handling and retry mechanisms in advance. The positioning server and UEs pre-configure fallback procedures and redundancy strategies that activate only when transmission issues are detected, cushioning against reliability problems without impacting normal operation.
Data Source
AI summary
This disclosure relates to techniques for positioning protocol enhancements for sidelink positioning. In an example, a method to be performed by a first user equipment (UE) includes receiving a positioning message over a sidelink interface between the first UE and a second UE, generating, by the first UE, a response to the positioning message, and transmitting the response to the second UE over the sidelink interface.