Fronthaul Synchronization via Adaptive Protocol

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Solution Overview

Problem

Traditional distributed Radio Access Networks (RANs) face challenges in synchronization, especially when using non-deterministic fronthaul links, which can lead to increased costs and complexity due to the need for carrier-grade GPS receivers and synchronous links.

Innovation Solution

The implementation of a distributed RAN using Radio-as-a-Service (RaaS) technology, where a baseband unit (BBU) communicates with remote radio units (RRUs) over a non-deterministic fronthaul link, utilizing an adaptive fronthaul protocol to enable synchronization through the processing and transmission of synchronization signals.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If carrier-grade GPS receivers and synchronous links are used for fronthaul communication, then synchronization precision is improved, but device complexity and cost increase

Engineering Contradiction:

Improvesynchronization precisionVSAvoiddevice complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent uses standard commercial GPS receivers instead of carrier-grade GPS receivers to obtain timing information. By copying the timing signals through standard protocols (NTP, PTP, or SIP) over existing IP networks, the system achieves adequate synchronization precision without requiring expensive carrier-grade hardware, thus reducing device complexity while maintaining functional equivalence

Inventive Principle:

Principle #26Copying

Solution Approach 2:

The patent replaces dedicated synchronous physical links with standard IP-based network protocols for fronthaul communication. By substituting the mechanical/specialized synchronous link infrastructure with software-based timing protocols (NTP, PTP, SIP) that run over existing Ethernet networks, the system achieves synchronization without requiring specialized hardware connections, thereby reducing device complexity and infrastructure costs

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Measurement precision

If carrier-grade GPS receivers and synchronous links are used for fronthaul communication, then synchronization precision is improved, but cost increases

Engineering Contradiction:

Improvesynchronization precisionVSAvoidcost

Core Design Contradiction:

Measurement precisionVSEase of manufacture

Solution Approach 1:

The patent employs standard commercial off-the-shelf (COTS) GPS receivers and networking equipment instead of expensive carrier-grade hardware. These standard components are significantly cheaper and can be readily replaced or upgraded, achieving the required synchronization precision at a fraction of the cost of traditional carrier-grade solutions while maintaining ease of deployment and maintenance

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The patent uses standard IP network infrastructure and protocols that serve multiple functions simultaneously. The same Ethernet network used for data communication also carries timing synchronization signals via NTP, PTP, or SIP protocols. This multi-functionality eliminates the need for separate dedicated synchronous links and carrier-grade GPS equipment, significantly reducing overall system cost while maintaining synchronization precision

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Device complexity

If standard IP-based protocols are used for fronthaul communication, then device complexity is reduced, but synchronization precision deteriorates

Engineering Contradiction:

Improvedevice complexityVSAvoidsynchronization precision

Core Design Contradiction:

Device complexityVSMeasurement precision

Solution Approach 1:

The patent implements feedback mechanisms where timing information is continuously exchanged between network elements using standard IP protocols. Through protocols like PTP (Precision Time Protocol) or NTP (Network Time Protocol), timing deviations are detected and corrected in real-time, allowing the system to maintain synchronization precision comparable to dedicated synchronous links while using standard IP-based infrastructure with reduced device complexity

Inventive Principle:

Principle #23Feedback

Data Source

PatentUS20250175917A1Device for fronthaul communication between a baseband unit and a remote unit of a radio access network

Publication Date: 2025.05.29 OUTDOOR WIRELESS NETWORKS LLC

AI summary

One embodiment is directed to a system for providing wireless service to user equipment (UE). The system comprises an intermediate device configured to communicate with a baseband unit (BBU) of a radio access network (RAN) and a plurality of remote units (RUs) communicatively coupled to the intermediate device. The intermediate device is configured to acquire synchronization for the RAN and to distribute synchronization information to the plurality of RUs. At least two of the RUs are configured to wirelessly transmit user data to a same UE. Said at least two of the RUs are configured to perform at least some physical layer processing for wirelessly transmitting the user data to the same UE.