RAN Node Buffer Retrieval for Wireless Data Recovery

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Solution Overview

Problem

In communication networks, particularly in LTE and 5G contexts, wireless devices experiencing radio link failures (RLF) often result in buffered data being lost when reconnecting to a different cell, as existing systems lack mechanisms to efficiently redirect or recover buffered packets from the previous RAN node, leading to poor network performance.

Innovation Solution

Implementing a mechanism where the second radio access network node or core network node identifies and retrieves buffered data from the first RAN node and forwards it to the wireless device, ensuring data integrity and reducing delays by maintaining the S1 connection and using Tracking RAN Area updates to locate the device.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the wireless device reconnects to a different cell after radio link failure, then the device can restore connectivity, but the buffered data at the original RAN node is lost

Engineering Contradiction:
Improveconnectivity restorationVSAvoidbuffered data loss
Core Design Contradiction:
ReliabilityVSLoss of information

Solution Approach 1:

The patent applies preliminary action by having the RAN node buffer data before the wireless device reconnects. The network node proactively retrieves and stores buffered data from the original RAN node before the device establishes connection with the new cell, ensuring data is preserved and can be forwarded later when the device reconnects.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent uses an intermediary approach by introducing a network node that acts as a mediator between the original RAN node and the wireless device. This network node retrieves buffered data from the original RAN node and forwards it to the device after reconnection, preventing direct data loss during the handover process.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If the wireless device initiates a new RRC connection after RLF, then the device can re-establish connectivity, but data recovery becomes impossible without CN signaling

Engineering Contradiction:
Improveconnectivity re-establishmentVSAvoiddata recovery delay
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent applies preliminary action by having the network node retrieve and store buffered data from the original RAN node before the wireless device completes its RRC connection re-establishment. This proactive data retrieval eliminates the need for time-consuming CN signaling and transport layer recovery mechanisms after connection is restored.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent enables skipping the lengthy CN signaling and transport layer recovery procedures by directly retrieving buffered data at the RAN level. The network node bypasses upper layer protocols and recovers data directly from the RAN node, significantly reducing recovery time.

Inventive Principle:
Principle #21Skipping (Rushing through)

3Productivity

If the CN releases the old S1 connection during re-establishment, then the network can manage resources efficiently, but all buffered packets are lost

Engineering Contradiction:
Improvenetwork resource managementVSAvoidbuffered packet loss
Core Design Contradiction:
ProductivityVSLoss of information

Solution Approach 1:

The patent uses an intermediary approach by introducing a network node that mediates between the CN resource management actions and the RAN node data buffer. This intermediary retrieves and preserves buffered data even when the CN releases the S1 connection, allowing resource management to proceed while preventing data loss.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent applies preliminary action by having the buffered data retrieved and preserved at the network node before the CN releases the old S1 connection. This ensures data is saved in advance of the resource management action that would otherwise cause data loss.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP3420749B1Methods and devices to forward data from first radio access network node to wireless device over a network node
Publication Date: 2022.05.25 TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)
  • EP3420749B1 patent drawingFigure 1
  • EP3420749B1 patent drawingFigure 2
  • EP3420749B1 patent drawingFigure 3

AI summary

Embodiments herein relate e.g. to a method performed by a network node (15,13) for handling data of a wireless device (10) in a communication network (1). The network node (15,13) receives an indication from the wireless device (10), which indication indicates a presence of the wireless device at a second radio access network node (13) holding no context for the wireless device (10). The network node (15,13) identifies a first radio access network node (12) holding context for the wireless device (10) and any buffered data destined for the wireless device (10). The network node (15,13) retrieves from the identified first radio access network node (12), data buffered for the wireless device (10), and forwards the retrieved data to the wireless device (10).