UE PDCP Duplication Switching After LBT Failure in Shared Spectrum
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Solution Overview
Problem
Existing wireless communication systems lack a flexible and dynamic mechanism for user equipment (UE) to autonomously activate or deactivate PDCP duplication in shared spectrum environments, leading to potential LBT failures and exceeding survival time limits for critical applications like URLLC.
Innovation Solution
A UE apparatus and method that initiates a listen before talk (LBT) procedure for MAC PDUs and selectively enables PDCP duplication based on LBT success or failure, allowing dynamic activation/deactivation of PDCP duplication to maintain transmission reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If PDCP duplication is deactivated and LBT is performed in shared spectrum, then spectrum sharing efficiency is improved, but transmission reliability deteriorates due to potential LBT failures
Solution Approach 1:
The patent implements dynamic switching between PDCP duplication modes based on LBT outcomes. When LBT succeeds, single transmission mode is used for spectral efficiency; when LBT fails, the system dynamically switches to PDCP duplication mode to ensure reliable delivery, thus adapting transmission strategy to real-time channel conditions
Solution Approach 2:
The patent changes the operational parameter of PDCP duplication status from a static network-configured state to a dynamically adjustable state based on LBT results. This parameter change enables the system to transition between duplication-active and duplication-inactive states, optimizing the trade-off between spectrum efficiency and transmission reliability
2Reliability
If PDCP duplication is always activated, then transmission reliability is improved, but device complexity and overhead increase
Solution Approach 1:
Instead of always activating PDCP duplication, the patent implements a dynamic activation mechanism triggered by LBT failure detection. The duplication function remains inactive under normal conditions and is only activated when necessary, reducing overall system complexity while maintaining reliability when needed
Solution Approach 2:
The UE autonomously determines when to activate PDCP duplication based on its own LBT performance without requiring continuous network control signaling. This self-service approach reduces signaling overhead and simplifies network-UE coordination while ensuring reliable transmission
3Reliability
If PDCP duplication is dynamically enabled after LBT failure, then transmission reliability is improved, but transmission delay increases due to retransmission
Solution Approach 1:
The patent prepares duplicate PDCP PDUs in advance at the PDCP layer before transmission attempts. When LBT failure occurs, these pre-prepared duplicates are immediately available for transmission without requiring generation time, thus minimizing delay while ensuring reliability
Solution Approach 2:
Upon detecting LBT failure, the system immediately switches to transmitting pre-prepared duplicate PDUs without waiting for network reconfiguration or additional processing steps. This rapid switching mechanism rushes through the reliability assurance process, minimizing the time loss associated with fallback procedures
Data Source
AI summary
Apparatuses, methods, and systems are disclosed for increasing the transmission reliability for transmissions of a duplication bearer in a shared or unlicensed spectrum. A UE apparatus for a mobile network (“NW”) includes a transceiver that initiates a listen before talk procedure (“LBT”) on shared spectrum, for transmission of a medium access control (“MAC”) protocol data unit (“PDU”) containing an original packet data convergence protocol (“PDCP”) PDU of a data radio bearer (“DRB”) configured for PDCP duplication, wherein PDCP duplication is deactivated for the DRB. The apparatus includes a processor that determines whether the LBT failed or succeeded and selectively enables PDCP duplication for the DRB in response to determining that the PDCP PDU was not transmitted due to failure of the LBT.