Managing UE Context for Early Data Transmission in Inactive State
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Solution Overview
Problem
There is a lack of clear methods for distributed base stations to manage user equipment (UE) context to support early data transmission (EDT) when the UE is in an inactive or idle state, particularly for uplink and downlink data transmission.
Innovation Solution
The distributed unit (DU) and/or central unit (CU) of a base station manage UE context by resuming or establishing tunnels using tunnel endpoint identifiers (TEIDs) and logical channel identifiers (LCIDs), enabling the transmission of uplink and downlink data without transitioning to the RRC_CONNECTED state.
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 connection establishment time and signaling overhead increase
Solution Approach 1:
The patent applies preliminary action by pre-establishing and maintaining UE context information (including tunnel endpoints, TEIDs, and routing information) in the RAN during RRC_INACTIVE state. When data needs to be transmitted, the existing context is immediately utilized without requiring full connection re-establishment, thus reducing connection establishment time while maintaining communication reliability.
2Loss of time
If the UE remains in RRC_INACTIVE state for data transmission, then connection establishment time is reduced, but clear methods for managing UE context in distributed base stations are lacking
Solution Approach 1:
The patent applies segmentation by dividing the base station into distributed units (DU) and central units (CU), with each segment responsible for specific context management functions. The DU handles local UE context storage and tunnel management, while the CU coordinates higher-level routing. This segmentation provides clear, modular methods for managing UE context in distributed architectures, reducing overall system complexity.
Solution Approach 2:
The patent introduces intermediary mechanisms including standardized interfaces (F1, X2, Xn) and protocol messages that facilitate coordinated context management between distributed base station components and the core network. These intermediaries enable seamless UE context sharing and tunnel establishment across distributed nodes, simplifying the complexity of multi-node coordination.
3Productivity
If existing tunnels are resumed for early data transmission, then data transmission efficiency is improved, but tunnel identification and management become more complex
Solution Approach 1:
The patent applies parameter changes by utilizing TEIDs (Tunnel Endpoint Identifiers) as key parameters for tunnel identification and differentiation. The system manages multiple tunnels by assigning and tracking unique TEID values, enabling efficient tunnel selection and routing decisions. This parameter-based approach simplifies tunnel management complexity through standardized identification mechanisms.
4Adaptability or versatility
If UE context is maintained in distributed base station components, then early data transmission capability is enabled, but resource consumption and context management overhead increase
Solution Approach 1:
The patent applies dynamics by implementing conditional UE context maintenance strategies. The system dynamically decides whether to maintain full UE context based on factors such as UE activity patterns, data transmission requirements, and network load conditions. This dynamic approach enables early data transmission capability when needed while reducing context storage requirements during inactive periods, optimizing the trade-off between adaptability and resource consumption.
Data Source
AI summary
A central unit control plane (CU-CP), a central unit user plane (CU-UP), and a distributed unit (DU) of distributed base station can implement a method for managing uplink or downlink early data transmission from or to a user equipment (UE) when the UE operates in an inactive state associated with a protocol for controlling radio resources. The method includes: determining the association of logical channel identifier(s) (LCID(s)), radio bearer identifier(s) (RB ID(s)), and tunnel endpoint identifier(s) (TEID(s)) for communicating data between the UE and the CU-UP without transitioning the UE to a connected state associated with the protocol.