PDCP Status Report Segmentation for Large Sequence Numbers
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Solution Overview
Problem
The extension of PDCP sequence number to 23 bits results in excessively large PDCP Control PDUs for PDCP status reports, making them impractical for transmission over the air interface or X2 interface, and exceeding the maximum defined PDCP data PDU size.
Innovation Solution
The method involves generating a partial PDCP status report that fits within a single PDCP Control PDU, either by truncating the bitmap, using a novel segmentation mechanism, or limiting the maximum size of the PDCP Control PDU, allowing for efficient transmission and processing of status reports.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If PDCP sequence number is extended to 23 bits, then the ability to track and manage larger numbers of PDCP packets is improved, but the size of PDCP Control PDU for status reports becomes excessively large
Solution Approach 1:
The patent divides the PDCP status report into multiple segments, each fitting within a single PDCP Control PDU. The status report is split across multiple PDUs with segment identifiers, allowing the receiver to reconstruct the complete status information without requiring excessively large individual control PDUs.
Solution Approach 2:
The patent extracts only the essential status information needed for retransmission decisions from the full status report, placing it in the PDCP Control PDU. Less critical or redundant status details are omitted or handled separately, reducing the control PDU size while maintaining functional effectiveness.
2Loss of information
If full PDCP status report is transmitted, then complete information about missing packets is provided, but transmission time and network resources are consumed
Solution Approach 1:
The patent transmits a partial status report containing only the most critical missing packet information in the initial PDCP Control PDU. This partial information is sufficient to enable immediate retransmission of high-priority packets, while complete status information is transmitted gradually in subsequent segments, reducing initial transmission time and resource consumption.
3Productivity
If PDCP Control PDU size is limited to maximum defined size, then efficient transmission and processing is achieved, but the ability to convey complete status information is reduced
Solution Approach 1:
The patent segments the complete status report into multiple PDCP Control PDUs, each within the maximum size limit. The segmentation includes segment identifiers and continuation indicators, enabling the receiver to assemble the full status information from multiple transmitted segments without losing completeness.
Solution Approach 2:
The patent transmits the most critical status information in the first PDCP Control PDU segment, enabling the receiver to immediately begin retransmission of high-priority missing packets. Subsequent segments provide additional status information, allowing progressive improvement of retransmission completeness while maintaining transmission efficiency.
Data Source
Figure 1
Figure 2A~2B
Figure 3A
AI summary
Amethod includes determining that a full PDCP status report does not fit into a single PDCP Control PDU, generating a partial PDCP status report that fits into the single PDCP Control PDU, and sending the single PDCP Control PDU containing the partial PDCP status report. Another method includes receiving a PDCP Control PDU where the maximum size thereof is limited, and determining that the received PDCP Control PDU contains a partial PDCP status report instead of a complete PDCP status report. Apparatus, program products, programs, UEs, base stations, and a communication system are also disclosed.