Base Station CU-DU Segmentation for Small Data Transmission
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current technologies face challenges in efficiently managing communication of uplink and downlink data between a user equipment (UE) and a distributed unit (DU) when the UE is in an inactive or idle state, particularly in supporting Small Data Transmission (SDT) procedures in 5G NR networks.
Innovation Solution
A base station determines to transition a UE from an inactive state to a connected state by performing a UE context procedure to obtain a non-SDT configuration, and processes information elements in interface messages to extract RRC messages, allowing for efficient data transfer and SDT operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the UE transitions to RRC_CONNECTED state for data transmission, then reliable data communication is achieved, but transition time and signaling overhead increase
Solution Approach 1:
The patent segments the base station into two functional units: Central Unit (CU) and Distributed Unit (DU). The CU handles RRC connection management and control plane functions, while the DU handles data transmission and user plane functions. This segmentation allows the UE to maintain RRC_INACTIVE state while enabling efficient data transmission through the DU, avoiding full RRC connection establishment.
Solution Approach 2:
The CU acts as an intermediary between the UE and the core network, managing the RRC state while the DU provides direct data transmission capabilities. This intermediary structure allows the system to maintain connection state information at the CU while enabling data transfer through the DU without requiring UE transition to RRC_CONNECTED.
2Loss of time
If the UE remains in RRC_INACTIVE state for small data transmission, then transition time is reduced, but support for non-SDT communication and full data transfer capability is limited
Solution Approach 1:
The system dynamically adapts between SDT and non-SDT communication modes based on data size and transmission requirements. The base station determines whether to transition the UE to RRC_CONNECTED state based on the specific communication needs, allowing flexible switching between inactive-state small data transmission and connected-state full data transmission.
Solution Approach 2:
The patent changes the operational parameters of the base station by implementing CU-DU separation, which enables different transmission modes (SDT and non-SDT) to be supported within the same RRC_INACTIVE state, expanding the adaptability of the system without requiring state transitions.
3Productivity
If the base station implements CU-DU separation for SDT, then data transmission efficiency is improved, but system complexity and coordination overhead increase
Solution Approach 1:
The patent extracts the RRC connection management functions into a separate CU entity, leaving the DU to handle data transmission efficiently. This extraction allows the DU to operate independently for SDT operations, improving data transmission efficiency while the CU handles the complexity of state management and coordination.
Solution Approach 2:
The CU is designed with multi-functionality to handle both RRC connection management and coordination with the DU. This universal design allows the CU to manage multiple UEs and coordinate with multiple DUs, reducing the overall system complexity by centralizing control functions.
Data Source
AI summary
A method, for transferring uplink data that includes control-plane or non-control plane information to a central unit (CU), is implemented by a distributed unit (DU) of a base station. The method includes receiving, from a user equipment (UE) in an inactive state, the uplink data via a logical channel, determining, based on the logical channel, whether to transmit the uplink data via a transport network layer protocol stack or in an uplink radio resource control (RRC) message transfer message, and transmitting the uplink data to the CU in accordance with the determining.