F1AP Common Configuration for Faster 5G RRC Initial Access
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Solution Overview
Problem
The initial access latency in 5G wireless communication networks is high due to multiple exchanges over the F1 Application Protocol (F1AP) between the Central Unit (CU) and Distributed Unit (DU) during the RRC setup phase, primarily because of functional splits and the need for UE-specific signaling and security algorithm selection.
Innovation Solution
Minimize interactions between the DU and CU during initial access by using non-UE specific information elements such as Radio Bearer Configuration for SRB1, common frequency band filters, and default security algorithms, which are exchanged upfront or deferred to later phases, allowing the DU to complete the RRC setup procedure independently.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If functional split between CU and DU is implemented with multiple F1AP exchanges, then traffic aggregation and resource sharing are improved, but initial access latency increases
Solution Approach 1:
The patent applies preliminary action by pre-configuring common information elements (Radio Bearer Configuration for SRB1, frequency band filters, security mode) in non-UE associated messages during F1 setup procedure. This allows the DU to have these configurations ready before actual UE access, eliminating the need for multiple F1AP exchanges during initial access and reducing latency.
Solution Approach 2:
The patent segments the information elements into UE-specific and non-UE-specific categories. Non-UE-specific elements are exchanged upfront in non-UE associated messages, while UE-specific elements are handled later. This segmentation allows the DU to complete initial access using pre-configured common information without waiting for CU involvement, thus reducing access latency while maintaining the functional split benefits.
2Reliability
If UE-specific signaling and security algorithm selection are performed during RRC setup, then connection security and customization are improved, but signaling overhead and access time increase
Solution Approach 1:
The patent applies preliminary action by pre-configuring security mode information and frequency band filters as non-UE specific elements during F1 setup. The DU stores these configurations and uses them during RRC setup without needing to exchange additional signaling with the CU, thus maintaining security requirements while reducing setup time.
Solution Approach 2:
The patent segments the security configuration into common (non-UE-specific) and UE-specific parts. The common security mode information is exchanged upfront and reused for multiple UEs, while UE-specific security algorithm selection is deferred or handled with default configurations. This reduces the signaling overhead during initial access while maintaining necessary security.
3Manufacturing precision
If multiple F1AP exchanges are conducted between CU and DU, then proper configuration and control are ensured, but signaling overhead and processing delay increase
Solution Approach 1:
The patent applies preliminary action by completing the exchange of common configuration information (Radio Bearer Configuration, frequency band filters, security mode) during the F1 setup procedure before any UE access occurs. This preliminary configuration ensures that the DU has all necessary common information ready, allowing it to handle UE access requests independently without requiring multiple F1AP exchanges during actual access, thus improving access speed while maintaining configuration accuracy.
Solution Approach 2:
The patent makes the Radio Bearer Configuration for SRB1 a universal (non-UE-specific) information element that is common for all UEs. This universal configuration is exchanged once during F1 setup and reused for all subsequent UE accesses, eliminating the need to repeat the same configuration exchanges for each UE and significantly improving access speed while ensuring consistent configuration accuracy.
Data Source
AI summary
An apparatus comprising means for receiving an interface setup request from a distributed unit of a wireless communication network; means for preparing a first information element for informing non-user equipment specific and common radio bearer configuration for a signalling radio bearer between a central unit and the user equipment; means for preparing a second information element for informing non-user equipment specific frequency band information; means for preparing a third information element for informing a common non-user equipment specific security mode related information; means for including the first information element, the second information element and the third information element in a setup response message; and means for sending the setup response message to the distributed unit.