Packet Gate Control for Deterministic Ethernet Fronthaul Timing

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Solution Overview

Problem

Current communication networks, particularly in the fronthaul domain of mobile communication networks, face challenges in maintaining low latency and Packet Delay Variation (PDV) for time-critical traffic, leading to reliance on proprietary dedicated networks despite the availability of Layer 2 Ethernet bridged networks.

Innovation Solution

A system with network elements and a controller that manage packet gates to control the relative transmission order of packet flows, using timing schemes and gate opening times to ensure deterministic packet arrival times, thereby reducing queuing delays and PDV across the network.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If multiple packet flows of the same traffic handling class share the same transmission resources, then network resource utilization is improved, but packet delay variation increases due to race conditions and uncontrolled queuing

Engineering Contradiction:

Improvenetwork resource utilizationVSAvoidpacket delay variation

Core Design Contradiction:

ProductivityVSManufacturing precision

Solution Approach 1:

The network controller determines and communicates gate opening time information to network elements in advance, allowing packet gates to be opened in a predetermined sequence. This preliminary action establishes a controlled transmission order for multiple packet flows before the actual transmission occurs, preventing race conditions and reducing packet delay variation while maintaining shared resource utilization

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system implements a feedback mechanism where the network controller receives information about packet flow characteristics and network state, then determines optimal gate opening times based on this feedback. This closed-loop control allows the system to adapt to varying traffic conditions while maintaining deterministic transmission ordering, thereby managing both resource utilization and delay variation dynamically

Inventive Principle:

Principle #23Feedback

2Manufacturing precision

If additional buffering is implemented to reduce packet delay variation, then PDV is improved, but packet delay increases due to buffering time

Engineering Contradiction:

Improvepacket delay variationVSAvoidpacket delay

Core Design Contradiction:

Manufacturing precisionVSLoss of time

Solution Approach 1:

Instead of using additional buffering to control packet delay variation, the invention applies preliminary action by determining gate opening times in advance and communicating them to network elements. This allows packets to be transmitted in a predetermined order with minimal buffering, reducing both packet delay variation and overall packet delay simultaneously

Inventive Principle:

Principle #10Preliminary action

Data Source

PatentUS10447583B2Packet processing technique for a communication network

Publication Date: 2019.10.15 TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)

AI summary

The present disclosure generally relates to packet processing by a network element system that transfers first and second packet flows of the same traffic handling class (e.g., the Ethernet express traffic class). A method aspect performed by the network element system comprises the step of receiving, from a network controller, information defining opening times for packet gates associated with network element ports. The opening times define a relative transmission order among first packet flow packets and second packet flow packets. Upon receipt of first and second packet flow packets at the respective ports, the packet gates are controlled based on the received information to trigger transmission of the first and second packet flow packets in the predefined transmission order.