CloudRAN RRC Setup Across Distributed and Centralized Units

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

There is no established method for establishing a radio resource control (RRC) connection between a terminal and a cloud radio access network (CloudRAN) in existing wireless network architectures.

Innovation Solution

A communication method is provided for establishing an RRC connection between a terminal and a cloud radio access network (CloudRAN) by using a RAN convergence unit (RANCU) and a RAN distribution unit (RANDU), involving a first RRC connection establishment between the terminal and the RANDU, and a second RRC connection establishment between the RANDU and the RANCU, with joint or separate determination by the RANCU and RANDU on allowing the connection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of time

If a traditional sequential RRC connection establishment method is used between terminal and CloudRAN, then the connection establishment process is simple to implement, but the connection establishment delay is excessive

Engineering Contradiction:
Improveconnection establishment delayVSAvoidconnection establishment process complexity
Core Design Contradiction:
Loss of timeVSDevice complexity

Solution Approach 1:

The RANCU performs preliminary actions by pre-establishing the RRC connection with the RANDU before the terminal connects. The RANCU sends an RRC connection establishment request to the RANDU in advance, and the RANDU prepares and returns connection configuration information beforehand. This preliminary setup eliminates waiting time during the actual terminal connection process, significantly reducing overall connection establishment delay.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The connection establishment process is segmented into two independent parts: (1) RANCU-RANDU connection establishment, and (2) terminal-RANDU connection establishment. These segments can proceed in parallel or alternating fashion, allowing the system to avoid sequential processing delays. The segmentation enables the RANCU and RANDU to independently manage their respective connection tasks without blocking each other.

Inventive Principle:
Principle #1Segmentation

2Reliability

If the RANCU and RANDU jointly determine connection establishment, then the connection reliability is improved, but the signaling overhead increases

Engineering Contradiction:
Improveconnection establishment reliabilityVSAvoidsignaling overhead
Core Design Contradiction:
ReliabilityVSLoss of information

Solution Approach 1:

The connection determination function is extracted and localized to the RANCU, which makes the final connection establishment decision independently. The RANCU receives connection requests from terminals, evaluates them according to configured criteria, and determines whether to establish connections without requiring continuous joint decision-making with the RANDU. This extraction maintains reliability through proper authorization while significantly reducing signaling overhead by eliminating redundant determination exchanges.

Inventive Principle:
Principle #2Taking out (Extraction)

Data Source

PatentEP3624484B1RRC connection establishment between a terminal and a cloud ran comprising a distributed unit and a centralized unit
Publication Date: 2025.10.29 HUAWEI TECH CO LTD
  • EP3624484B1 patent drawingFigure 1
  • EP3624484B1 patent drawingFigure 2
  • EP3624484B1 patent drawingFigure 3

AI summary

A communication method provided in embodiments of this application is a method for establishing an RRC connection between a terminal and a RAN, and the establishment of the RRC connection includes first RRC connection establishment and second RRC connection establishment. The first RRC connection establishment is a wireless RRC connection between the terminal and a first RAN network element, and the second RRC connection establishment is a wireless or wired RRC connection between the first RAN network element and a second RAN network element. A detailed process is as follows: The RAN includes the first RAN network element and the second RAN network element, the first RAN network element and the second RAN network element are interconnected, and the first RAN network element determines whether to allow the establishment of the RRC connection between the terminal and the RAN, or the first RAN network element and the second RAN network element jointly determine whether to allow the establishment of the RRC connection between the terminal and the RAN, to establish the RRC connection between the terminal and the RAN.