PDCP Reordering for Dual Connectivity Data Integrity

Solution Overview

Problem

In wireless communication systems supporting dual connectivity, existing technologies face challenges in efficiently reordering and decompressing Packet Data Convergence Protocol (PDCP) Protocol Data Units (PDUs) received from multiple Radio Link Control (RLC) entities, particularly due to non-ideal backhaul interfaces and distributed scheduling nodes, which affect data delivery sequence and integrity.

Innovation Solution

A method and apparatus for a user equipment (UE) that receives PDCP PDUs from two RLC entities, reorders them, deciphers, and decompresses the headers, using state variables and timers to ensure in-order delivery without duplication, thereby supporting dual connectivity by managing PDCP PDUs across multiple base stations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If data is received from multiple RLC entities in dual connectivity mode, then data throughput and service availability are improved, but data delivery sequence and integrity are compromised due to non-ideal backhaul interfaces and distributed scheduling nodes

Engineering Contradiction:

Improvedata throughputVSAvoiddata delivery sequence

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The patent applies preliminary action by performing reordering of PDCP PDUs before deciphering and header decompression. The receiving UE reorders PDCP PDUs received from multiple RLC entities based on PDCP sequence numbers before passing them to upper layers, ensuring in-order delivery is established prior to further processing. This preliminary reordering action prevents out-of-sequence delivery issues that would otherwise occur in dual connectivity scenarios.

Inventive Principle:

Principle #10Preliminary action

2Reliability

If PDCP PDUs are reordered before deciphering, then in-order delivery is achieved, but processing complexity and time are increased

Engineering Contradiction:

Improvein-order deliveryVSAvoidprocessing time

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The patent applies segmentation by separating the reordering function from the deciphering and header decompression functions. The receiving UE performs reordering of PDCP PDUs as a distinct step before deciphering, using PDCP sequence numbers to determine order. This segmentation allows the system to maintain reliability through proper reordering while managing processing time by handling each function in a structured sequence rather than simultaneously.

Inventive Principle:

Principle #1Segmentation

3Speed

If data is delivered to upper layers without reordering, then processing speed is maintained, but data integrity and sequence are compromised

Engineering Contradiction:

Improveprocessing speedVSAvoiddata sequence integrity

Core Design Contradiction:

SpeedVSLoss of information

Solution Approach 1:

The patent applies preliminary action by performing reordering of PDCP PDUs before deciphering and header decompression. The receiving UE reorders PDCP PDUs received from multiple RLC entities based on PDCP sequence numbers before passing them to upper layers, ensuring in-order delivery is established prior to further processing. This preliminary reordering action prevents out-of-sequence delivery issues that would otherwise occur in dual connectivity scenarios.

Inventive Principle:

Principle #10Preliminary action

Data Source

PatentUS9628586B2PDCP operation in a wireless communication system supporting dual connectivity

Publication Date: 2017.04.18 LG ELECTRONICS INC

AI summary

PDCP operations in a wireless communication system supporting dual connectivity are disclosed. According to this scheme, when the PDCP of the UE receives PDCP PDU from two RLCs, the PDCP reordering is performed first on the received PDCP PDU. Then, deciphering and decompressing are performed after the PDCP reordering.