Donor Access Node Smart Forwarding for Wireless Handover

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Solution Overview

Problem

Existing wireless telecommunications systems face challenges in efficiently handing over user equipment (UE) from a relay node to a target access node, especially when the UE moves between cells, leading to potential data packet loss and increased processing time due to redundant data forwarding.

Innovation Solution

The implementation of 'smart forwarding' schemes, such as using synchronous Packet Data Convergence Protocol (PDCP) Sequence Numbers and early S1 path switching, where the donor access node identifies and forwards only necessary packets to the target access node, reducing redundant data transmission and improving handover efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional data forwarding methods are used during handover, then all data packets are forwarded from source to target access node, but this causes redundant data transmission and increased processing time

Engineering Contradiction:
Improvehandover reliabilityVSAvoidhandover processing time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent applies preliminary action by performing S1 path switching before the actual handover is complete. The target access node is pre-configured with the necessary data packets and S1 path is established in advance, so that when handover occurs, data transmission can immediately resume without waiting for full data forwarding, thereby reducing handover processing time while maintaining reliability

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent extracts only the necessary data packets for forwarding during handover by using PDCP sequence numbers to identify which packets need to be transferred. Instead of forwarding all packets from source to target access node, only the relevant subset is extracted and forwarded, eliminating redundant data transmission and reducing processing time

Inventive Principle:
Principle #2Taking out (Extraction)

2Reliability

If all data packets are forwarded during handover, then data completeness is maintained, but spectral efficiency is reduced due to redundant transmissions

Engineering Contradiction:
Improvedata completenessVSAvoidspectral efficiency
Core Design Contradiction:
ReliabilityVSLoss of energy

Solution Approach 1:

The patent extracts only the necessary data packets for forwarding during handover by using PDCP sequence numbers to identify which packets need to be transferred. Instead of forwarding all packets from source to target access node, only the relevant subset is extracted and forwarded, eliminating redundant data transmission and reducing spectral efficiency loss

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent uses feedback mechanisms where the target access node receives information about which data packets have been successfully delivered to the UE. This feedback allows the system to determine exactly which packets need to be forwarded, avoiding redundant transmissions and improving spectral efficiency while maintaining data completeness

Inventive Principle:
Principle #23Feedback

3Productivity

If PDCP Sequence Numbers are used for smart forwarding, then redundant data transmission is reduced, but implementation complexity increases

Engineering Contradiction:
Improvehandover efficiencyVSAvoidforwarding mechanism complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent uses PDCP Sequence Numbers as a parameter change approach. By leveraging the existing sequence number mechanism already present in the PDCP protocol, the system can identify and forward only necessary packets without requiring complex new protocols or mechanisms. This approach improves handover efficiency while minimizing the increase in implementation complexity by building on existing standardized parameters

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP2306768B1Architecture for termination at access device
Publication Date: 2019.05.22 BLACKBERRY LTD
  • EP2306768B1 patent drawingFigure 1
  • EP2306768B1 patent drawingFigure 2
  • EP2306768B1 patent drawingFigure 3

AI summary

A method is provided for handing over a user equipment (UE). The method includes a donor access node with which the UE is in communication via a relay node receiving UE context information from the relay node. The method further includes the donor access node using the UE context information to identify data packets that belong to the UE.