Distributed RRC Architecture for Low-Latency Split Access Nodes
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Solution Overview
Problem
In wireless communication networks with split access node architecture, the existing RRC signaling is routed through the central unit, leading to inefficiencies and latency due to the central unit's lack of specific information about lower layer configurations, resulting in complex connections and increased latency for RRC message handling.
Innovation Solution
Implementing a split RRC architecture where RRC connection is identified with a CU-specific RRC identity independent of a particular cell, allowing the distributed unit to handle lower layer configurations directly, with the central unit providing necessary context and security keys, enabling independent RRC entities and separate signaling radio bearers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If RRC signaling is routed through the central unit in split access node architecture, then central unit can provide unified control, but latency increases and efficiency decreases due to central unit's lack of specific information about lower layer configurations
Solution Approach 1:
The patent segments RRC functionality by introducing independent RRC entities at the distributed unit level, separate from the central unit. Each distributed unit has its own RRC entity that can handle RRC signaling locally without routing through the central unit, thereby reducing latency while maintaining centralized coordination through the F1 interface for context transfer and security key distribution.
2Ease of operation
If RRC connection is identified with cell-specific identity, then cell-specific control is simplified, but adaptability decreases when device moves between cells or connects to multiple DUs
Solution Approach 1:
The patent implements a universal RRC identity (gNB-RRC-Identity) that is independent of both cell and DU-specific identifiers. This single RRC identity can be used across multiple cells and DUs, allowing a device to maintain its RRC connection regardless of which cell or DU it connects to, thereby achieving both simplified control and high adaptability.
3Productivity
If distributed unit handles all RRC configurations independently, then processing efficiency improves, but security and integrity control weakens
Solution Approach 1:
The patent introduces the F1 interface as an intermediary between the central unit and distributed unit. The central unit transfers necessary context information and security keys (KgNB, KRRC, KUP) to the distributed unit through this controlled interface, enabling the distributed unit to handle RRC configurations independently while maintaining security and integrity control from the central unit.
4Reliability
If complex connections are established for RRC message handling, then connectivity reliability improves, but system complexity increases
Solution Approach 1:
The patent extracts the RRC entity from the central unit and places it at the distributed unit level. This extraction simplifies the connection structure by eliminating the need for complex routing through the central unit for local RRC messages, while the F1 interface provides a standardized, controlled mechanism for context and security key transfer, thereby reducing overall system complexity.
Data Source
AI summary
Various example embodiments relate to radio resource control in a communication network. A method may comprise: receiving, by a distributed unit of an access node, a radio resource control identity of a device and an access stratum context associated with the radio resource control identity from a central unit of the access node: configuring, based on the access stratum context, a radio resource control entity of the distributed unit of the access node for delivery of radio resource control data to the device over a signaling radio bearer: generating radio resource control data for the device; and transmitting the radio resource control data to the device on the signaling radio bearer.