vRAN PHY Failure Detection With Programmable Switch Failover

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Solution Overview

Problem

The challenge in virtualized radio access networks (vRANs) is the efficient handling of PHY layer failures due to strict real-time latency requirements and high software complexity, which can cause severe service disruptions.

Innovation Solution

A programmable switch-based mechanism is employed to detect PHY failures by monitoring downlink fronthaul packets and reroute fronthaul traffic to a backup server within 500 microseconds, utilizing a programmable switch to update routing tables in the data plane for seamless failover.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a programmable switch-based mechanism is used to detect PHY failures and reroute traffic, then the failure detection speed and reliability are improved, but the device complexity increases

Engineering Contradiction:

ImprovePHY failure detection reliabilityVSAvoidprogrammable switch complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

A programmable switch is introduced as an intermediary device between the radio unit and the virtualized RAN infrastructure. This switch monitors downlink fronthaul packets and automatically reroutes traffic when PHY failures are detected, providing fast and reliable failure detection without requiring complex changes to the core RAN software stack.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The system separates the failure detection and routing functions from the main RAN processing functions by implementing them in the data plane of the programmable switch. This segmentation allows the control plane to remain simple while the data plane handles the complex real-time monitoring and rerouting operations.

Inventive Principle:

Principle #1Segmentation

2Loss of time

If failure detection and rerouting is implemented in the control plane, then the system complexity is reduced, but the failure detection latency increases beyond the 500 microsecond requirement

Engineering Contradiction:

Improvefailure detection latencyVSAvoiddata plane implementation complexity

Core Design Contradiction:

Loss of timeVSDevice complexity

Solution Approach 1:

The patent replaces the traditional control-plane-based failure detection mechanism with a data-plane implementation in the programmable switch. This substitution enables sub-millisecond failure detection by leveraging the switch's inherent packet inspection and routing capabilities, which operate at line rate without the latency overhead of control plane processing.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Adaptability or versatility

If traditional hardware for RAN processing is replaced with virtualized software, then the system flexibility and adaptability are improved, but the real-time latency performance deteriorates

Engineering Contradiction:

ImprovevRAN flexibilityVSAvoidreal-time processing speed

Core Design Contradiction:

Adaptability or versatilityVSSpeed

Solution Approach 1:

The programmable switch is pre-configured with routing rules and failure detection parameters before operation. When PHY failures occur, the switch can immediately reroute traffic based on pre-established criteria, eliminating the need for real-time decision-making and complex software processing during failure events.

Inventive Principle:

Principle #10Preliminary action

Data Source

PatentEP4533843B1Detection of failures in virtualized radio access networks

Publication Date: 2026.03.11 MICROSOFT TECHNOLOGY LICENSING LLC

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AI summary

Data traffic is communicated between a radio unit (RU) of a cellular network and a virtualized radio access network (vRAN) instance of a vRAN. In response to determining that the vRAN instance has failed to communicate a downlink fronthaul packet to the RU within a threshold timeout interval, a failure notification is sent to a PHY layer failure response function. The failure to communicate the downlink fronthaul packet to the RU within the threshold timeout interval is indicative of a failure of the vRAN instance.