PC5 Link Establishment with UE Identification to Prevent Duplicate Links
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Solution Overview
Problem
Existing PC5 link establishment methods in V2X communications result in the establishment of multiple links for the same service, leading to resource waste and failure to identify accepting UEs, thereby hindering effective link establishment.
Innovation Solution
The method involves sending a direct communication request message carrying a unique identifier of the first UE and receiving a direct communication accept message with a corresponding identifier of the second UE, ensuring successful and unique link establishment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If UE 1 broadcasts a direct communication request message with a changed layer 2 address to establish another PC5 link, then UE 2 can establish another PC5 link with UE 1, but multiple PC5 links for the same service are established between UE 1 and UE 2, resulting in waste of air interface resources
Solution Approach 1:
The patent applies preliminary action by having UE 1 pre-generate and store multiple request message copies with different layer 2 addresses before broadcasting. When establishing PC5 links, UE 1 can directly use these pre-prepared messages rather than generating new ones each time, preventing duplicate link establishment while maintaining the ability to connect with multiple UEs. This resolves the contradiction by preparing link establishment capabilities in advance without actually creating redundant links.
Solution Approach 2:
The patent implements feedback mechanisms where UEs exchange acceptance information in response to direct communication request messages. When UE 1 broadcasts a request message, receiving UEs can send back acceptance indications, allowing UE 1 to identify which UEs have successfully established links. This feedback loop prevents wasteful re-broadcasting and ensures that multiple links are only established when actually needed and accepted, thereby avoiding air interface resource waste while maintaining adaptability.
2Adaptability or versatility
If the direct communication request message carries identifiers of a plurality of UEs, then multiple UEs can potentially accept the request, but only some of the UEs may reply with direct communication accept messages, leading to PC5 link establishment failure
Solution Approach 1:
The patent applies segmentation by dividing the multi-UE link establishment process into individual one-to-one interactions. Instead of attempting to establish links with multiple UEs simultaneously through a single broadcast, UE 1 segments the process by maintaining separate request message copies for different target UEs, each with appropriate identifiers. This segmentation ensures that each link establishment attempt is independent and can be reliably tracked, resolving the contradiction between multi-UE adaptability and link establishment reliability.
Solution Approach 2:
The patent implements comprehensive feedback mechanisms where each receiving UE sends back acceptance information specifically indicating whether it accepts the direct communication request. This feedback allows UE 1 to reliably identify which specific UEs have successfully established links among the plurality of targeted UEs. The feedback loop ensures that even when multiple UEs are targeted, the system can reliably determine actual link establishment status, thereby maintaining both adaptability and reliability.
Data Source
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AI summary
Embodiments of this disclosure provide a method for PC5 link establishment, a device, and a system. The method includes: sending, by first UE, a direct communication request message, where the direct communication request message carries an identifier of the first UE, and is used to request establishment of a PC5 link; and receiving, by the first UE, a direct communication accept message sent by second UE, where the direct communication accept message carries an identifier of the second UE, and is used to accept the establishment of the PC5 link with the first UE.