CU-DU Split Support for MT-EDT in Wireless Systems

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Solution Overview

Problem

There is no consideration for supporting Mobile Terminated (MT)-Early Data Transmission (EDT) in the context of Central Unit (CU)-Distributed Unit (DU) split within an eNodeB or gNodeB in wireless communication systems.

Innovation Solution

A method where the Central Unit (CU) of a Radio Access Network (RAN) node receives information from the Distributed Unit (DU) related to a transport block used for a wireless device, and based on this information, the CU decides the Radio Resource Control (RRC) state for transmitting downlink data to the wireless device.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If MT-EDT procedure is implemented without CU-DU split consideration, then early data transmission can be achieved, but the system cannot support the functional split between CU and DU for RRC state decision-making

Engineering Contradiction:

Improvesupport for CU-DU splitVSAvoidRRC state decision complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent segments the RRC state decision-making process by identifying specific conditions that trigger different RRC states (RRC_INACTIVE or RRC_CONNECTED). The CU receives transport block information from the DU and independently decides the appropriate RRC state based on predefined criteria, allowing the system to support CU-DU split while maintaining clear decision boundaries.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The CU acts as an intermediary between the DU and the core network for RRC state management. It receives transport block size information from the DU, processes this information along with downlink data size, and determines the appropriate RRC state, thereby mediating the complexity between the radio access functions and the core network.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Productivity

If the DU handles transport block information, then radio layer functions can be distributed, but the CU lacks information to decide the appropriate RRC state

Engineering Contradiction:

Improvedata transmission efficiencyVSAvoidRRC state decision information

Core Design Contradiction:

ProductivityVSLoss of information

Solution Approach 1:

The patent establishes a feedback mechanism where the DU provides transport block size information to the CU. This feedback loop enables the CU to make informed RRC state decisions by receiving necessary information from the DU about the transport block characteristics, ensuring that the CU has the information needed to decide between RRC_INACTIVE and RRC_CONNECTED states.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The CU is designed to perform multiple functions: it manages RRC state decisions, receives transport block information from the DU, and determines the appropriate RRC state based on combined information about downlink data size and transport block characteristics. This multi-functionality allows the CU to handle both the information gathering and decision-making processes.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Data Source

PatentUS12284629B2Method and apparatus for support of CU-DU split in MT-EDT procedure in a wireless communication system background

Publication Date: 2025.04.22 LG ELECTRONICS INC

AI summary

A method and apparatus for support of CU-DU split in MT-EDT procedure in a wireless communication system is provided. A Central Unit (CU) of a Radio Access Network (RAN node) receives, from a Distributed Unit (DU) of the RAN node, second information related to a transport block used for the wireless device. The CU decides a Radio Resource Control (RRC) state for transmitting the downlink (DL) data to the wireless device based on the first information related to the DL data and the second information related to the transport block.