Multi-Path PDCP Duplicate PDU Discarding for Reliable Delivery
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Solution Overview
Problem
In wireless communication systems, existing methods for duplicate PDU discarding in multi-path transmission are inefficient, particularly in scenarios where direct and indirect paths have varying reliability, leading to potential loss of data packets due to improper handling of acknowledgments across different RLC entities.
Innovation Solution
A method and apparatus that prevents a PDCP entity from indicating to a first RLC entity to discard a PDCP PDU when successful delivery is confirmed by a second RLC entity in an indirect path, ensuring data integrity by maintaining the PDCP PDU in the direct path until confirmed by the network.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the PDCP entity indicates to the first RLC entity to discard a PDCP PDU when successful delivery is confirmed by the second RLC entity, then the device complexity is reduced, but the reliability of data transmission deteriorates due to potential loss of data packets
Solution Approach 1:
The patent applies local quality by making the discard decision path-dependent. When the second RLC entity (indirect path) confirms successful delivery, the PDCP entity does not discard the PDU. However, when the first RLC entity (direct path) confirms successful delivery, the PDCP entity may discard the PDU. This path-specific quality differentiation resolves the contradiction by adapting the discard behavior to the specific transmission path characteristics.
Solution Approach 2:
The patent inverts the conventional discard logic. Instead of discarding the PDCP PDU when any RLC entity confirms successful delivery, the system inverts the logic to prevent discarding when the indirect path (second RLC entity) confirms delivery. This inversion protects against premature discarding while maintaining the ability to discard when the direct path confirms delivery, thus improving reliability without significantly increasing complexity.
2Adaptability or versatility
If the system uses multiple RLC entities for direct and indirect paths, then the adaptability of the communication system is improved, but the device complexity increases due to additional PDCP entity control logic
Solution Approach 1:
The patent applies local quality by implementing path-specific discard behavior. The PDCP entity maintains separate handling logic for the direct path (first RLC entity) and indirect path (second RLC entity). When the indirect path confirms delivery, the PDCP entity prevents discarding, while the direct path confirmation may trigger discarding. This localized quality control enables multi-path adaptability without requiring complex global coordination logic.
3Reliability
If the PDCP entity prevents discarding PDCP PDUs confirmed by the second RLC entity, then the reliability of data transmission is improved, but the productivity of the system decreases due to retained packets that may not be needed
Solution Approach 1:
The patent applies local quality by implementing differentiated discard behavior for different transmission paths. The PDCP entity prevents discarding only when the indirect path (second RLC entity) confirms delivery, while maintaining the ability to discard when the direct path (first RLC entity) confirms delivery. This localized approach improves reliability for indirect path transmissions without unnecessarily retaining packets from direct path transmissions, thus balancing reliability and productivity.
Solution Approach 2:
The patent applies partial action by selectively preventing discarding only for PDCP PDUs confirmed by the indirect path, rather than preventing discarding for all PDCP PDUs regardless of path. This partial prevention approach improves reliability where needed (indirect path) while maintaining efficiency where possible (direct path), avoiding the excessive action of universally retaining all packets.
Data Source
AI summary
A method and device for duplicate PDU discarding. In one embodiment, a User Equipment (UE) establishes a direct path and an indirect path to communicate with a network. The UE also establishes a radio bearer, wherein the radio bearer is mapped to a first Radio Link Control (RLC) entity and a second RLC entity and wherein the first RLC entity is used for communication with the network over the direct path and the second RLC entity is used for communication with the network over the indirect path. In addition, a Packet Data Convergence Protocol (PDCP) entity, which is in the UE and which is associated with the radio bearer, prevents from indicating to the first RLC entity to discard a first PDCP PDU when successful delivery of the first PDCP PDU is confirmed by the second RLC entity.