UE Capability Segmentation Retransmission Delay Reduction
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Solution Overview
Problem
In 5G standalone (SA)/non-standalone (NSA) architecture systems, user equipment (UE) faces delays in transmitting UE capability information due to the need to split this information into multiple segments, which can lead to undelivered segments and increased latency in attachment procedures, particularly for high-priority services.
Innovation Solution
The UE is configured to request joint acknowledgement of multiple segments of UE capability information and to retransmit segments based on detection of transmission failures, thereby reducing latency by modifying network parameters such as the poll retransmission timer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If UE capability information is transmitted via multiple segments, then the complete capability information can be delivered, but the transmission delay increases due to poll retransmission timer waiting
Solution Approach 1:
The UE capability information is divided into multiple segments for transmission. Each segment is transmitted separately with individual acknowledgment requests, allowing the network to acknowledge receipt of each segment independently. This segmentation enables reliable delivery of large capability information sets while reducing overall transmission delay through parallel processing and independent retransmission of only failed segments.
Solution Approach 2:
The patent implements a feedback mechanism where the network sends acknowledgments for each received segment. The UE monitors these acknowledgments and triggers retransmission of undelivered segments by setting a poll bit in subsequent RLC PDUs. This feedback-driven approach ensures reliable delivery while minimizing delay by retransmitting only the specific segments that failed, rather than waiting for a fixed timer expiration.
2Reliability
If poll retransmission timer uses default high value, then network has time to process and acknowledge segments, but attachment procedure completion is significantly delayed
Solution Approach 1:
The UE proactively sets the poll bit in RLC PDU headers before transmitting capability information segments. This preliminary action ensures that the network is immediately notified to send acknowledgments without waiting for default timer expiration. The poll bit mechanism initiates the acknowledgment process in advance, enabling faster attachment procedure completion while maintaining reliable acknowledgment receipt.
3Productivity
If UE transmits next segment without receiving prior acknowledgment, then transmission continues efficiently, but undelivered segments cause capability information gaps
Solution Approach 1:
The UE implements a feedback monitoring mechanism where it waits for acknowledgments of transmitted segments before proceeding with subsequent transmissions. If an acknowledgment is not received within a specified time, the UE triggers a retransmission by setting the poll bit. This feedback-based approach maintains transmission efficiency by avoiding unnecessary delays while ensuring capability information completeness through reliable retransmission of undelivered segments.
Data Source
AI summary
Some aspects described herein relate to reducing a delay in the retransmission of undelivered capability information segments. For example, when transmitting capability information via multiple segments, a UE may request the network to acknowledge each segment and/or may modify a network configured parameter to reduce the delay in retransmitting undelivered segments. In some aspects, a UE may attach to a network for a priority service, such as an emergency service or a short message service. In connection with the attachment, the UE may provide a reduced set of capability information that is relevant to the priority service and that omits at least some capability information irrelevant to the priority service.