[5g] what are Cu and Du in 5g?

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I work for an international well-known terminal manufacturer , be responsible for modem Chip development .
stay 5G In the early stage, he was responsible for the terminal data service layer 、 Core network related development work , Current lead 6G Research on technical standards of computational power network .


The content of the blog mainly focuses on ：
       5G/6G Explanation of the agreement
        Explanation of computational power network （ Cloud computing , Edge of computing , End calculation ）
        senior C Language explanation
       Rust Language explanation

5G Medium CU and DU

Previous blogs 《【5G framework 】5G Overview of access network architecture 》 There is an introduction to CU and DU The content of , This blog is a supplement to the previous blog

5G The base station is called gNB , It is divided into two physical entities ：

• CU (Centralized Unit);
• DU (Distributed Unit).

CU Support the upper layer of the protocol stack , Such as SDAP、PDCP、RRC. and DU Support the lower layer of the protocol stack , Such as RLC、MAC、 The physical layer . in addition , Please note that , If CU Connect to 4G Core The Internet , Will not appear SDAP layer .

actually , Every gNB Corresponding to one CU, But one CU You can control multiple DU, For example, one CU Can be connected 100 Multiple DU.

And 4G The difference between base stations is , Every DU Can support one or more cell, So a gNB It can control hundreds cell. in addition , Be careful CU and DU The interface between is named F1, according to 3GPP, It should be an open interface , Therefore, suppliers X One of the CU Connect to the supplier Y One of the DU On .

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