Multi-RAT CU Physical Layer Split for LTE and 5GNR Interworking

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Current wireless network technologies, specifically the Central Unit (CU) circuitry, face inefficiencies in serving multiple Radio Access Technologies (RATs) like LTE, 5GNR, and WIFI due to non-optimized Packet Data Convergence Protocol (PDCP) components, which hinder effective and efficient data communication across different user equipment types.

Innovation Solution

The implementation of a multi-RAT Central Unit (CU) circuitry with a Physical Layer (PHY) split, where the CU processes and converts signaling and data between different RATs, including converting 5G RRC signaling to LTE RRC signaling and transferring LTE/5GNR Physical Layer High (PHY-H) signaling to Physical Layer Low (PHY-L) in Distributed Units (DUs), enabling efficient interworking of PDCP components across LTE, 5GNR, and WIFI networks.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If protocol split technology is used to move network software applications from DU to CU, then device complexity is reduced and adaptability is improved, but manufacturing precision and operational efficiency deteriorate due to non-optimized PDCP components

Engineering Contradiction:

Improveability to serve multiple RATsVSAvoidPDCP component optimization

Core Design Contradiction:

Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The patent segments the PDCP component into separate optimized instances for different RATs (LTE PDCP component, 5GNR PDCP component) within the CU circuitry. Each segmented PDCP component is specifically optimized for its corresponding RAT protocol requirements, allowing the system to maintain high manufacturing precision for each component while serving multiple RATs simultaneously.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent applies local quality by implementing RAT-specific optimized PDCP components rather than a generic unified component. The LTE PDCP component is optimized for LTE protocols while the 5GNR PDCP component is optimized for 5GNR protocols, ensuring each local component has the precise quality needed for its specific function.

Inventive Principle:

Principle #3Local quality

2Adaptability or versatility

If multiple RATs are served by a single CU, then adaptability improves, but device complexity increases due to handling multiple protocols

Engineering Contradiction:

Improvemulti-RAT supportVSAvoidCU circuitry complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The CU circuitry is segmented into distinct functional components including LTE PDCP component, 5GNR PDCP component, and multi-RAT PDCP component. Each segment handles specific RAT protocols independently, reducing the complexity burden on any single component while maintaining overall multi-RAT capability.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent implements a multi-RAT PDCP component that provides universal functionality across multiple RATs. This universal component can handle both LTE and 5GNR protocols, reducing the need for completely separate processing paths while maintaining protocol-specific optimization through its relationship with the RAT-specific PDCP components.

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Adaptability or versatility

If PHY split is implemented between CU and DU, then adaptability and modularity improve, but loss of information increases due to signaling transfer requirements

Engineering Contradiction:

Improveprotocol split capabilityVSAvoidsignaling conversion accuracy

Core Design Contradiction:

Adaptability or versatilityVSLoss of information

Solution Approach 1:

The patent introduces the multi-RAT PDCP component as an intermediary between the higher-layer RRC components and the lower-layer PHY components. This intermediary ensures accurate information transfer and conversion between different RAT protocols during the PHY split, preventing loss of information by properly managing the signaling conversions between LTE and 5GNR protocols.

Inventive Principle:

Principle #24Intermediary (Mediator)

4Manufacturing precision

If RAT-specific PDCP components are used, then manufacturing precision improves, but device complexity increases

Engineering Contradiction:

ImprovePDCP component optimizationVSAvoidnumber of PDCP components

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The PDCP functionality is segmented into specialized components (LTE PDCP, 5GNR PDCP, multi-RAT PDCP) where each segment handles specific protocol requirements. This segmentation achieves manufacturing precision for each component while the modular structure manages complexity by allowing independent development and deployment of each segment.

Inventive Principle:

Principle #1Segmentation

Data Source

PatentUS11265957B2Physical layer split in a multi-radio access technology (RAT) central unit (CU)

Publication Date: 2022.03.01 T MOBILE INNOVATIONS LLC

AI summary

A Central Unit (CU) receives Fifth Generation Core (5GC) N2 signaling and generates Fifth Generation New Radio (5GNR) RRC signaling. The CU receives 5GC N1 signaling. The CU converts a first portion of the 5GNR RRC signaling into LTE RRC signaling and converts a first portion of the 5GC N1 signaling into LTE Non-Access Signaling (NAS). The CU transfers LTE Physical Layer High (PHY-H) signaling to an LTE Physical Layer Low (PHY-L) in an LTE Distributed Unit (DU). The CU transfers 5GNR PHY-H signaling to an 5GNR PHY-L in a 5GNR DU. The LTE DU receives the LTE PHY-H signaling and transfers the LTE RRC signaling and the LTE NAS signaling to LTE User Equipment (UE). The 5GNR DU receives the 5GNR PHY-H signaling and transfers the second portion of the 5GNR RRC signaling and the second portion of the 5GC N1 signaling to a 5GNR UE.