Network-Controlled RLF Recovery in 3GPP Communication Systems
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Solution Overview
Problem
Current 3GPP telecommunications systems face challenges in efficiently recovering from Radio Link Failure (RLF), leading to unacceptable service delays and unnecessary signaling spikes, especially when there is no pending uplink data, resulting in delayed downlink data delivery and potential service interruptions.
Innovation Solution
A method is introduced where the network sends information to the User Equipment (UE) to determine actions in response to RLF, allowing the UE to decide on and perform recovery actions based on received instructions, enabling or disabling Non-Access Stratum (NAS) signaling recovery, thus providing operators with the option to manage RLF recovery procedures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the UE autonomously triggers NAS recovery procedures after RLF, then connection recovery is achieved, but signaling spikes occur and service delays increase when there is no pending uplink data
Solution Approach 1:
The invention changes the parameter of NAS recovery triggering condition from autonomous to network-controlled. The network configures a parameter indicating whether NAS specific recovery is allowed, and the UE adjusts its recovery behavior based on this parameter, thereby avoiding unnecessary recovery procedures and reducing signaling spikes and service delays
Solution Approach 2:
The network provides feedback to the UE through configuration information indicating whether NAS specific recovery is permitted. This feedback mechanism allows the network to control UE behavior based on current network conditions, preventing unnecessary recovery actions that would cause signaling spikes and delays
2Reliability
If the UE performs cell reselection after RLF, then radio link recovery is achieved, but downlink data delivery is delayed due to network unawareness of UE location
Solution Approach 1:
The UE performs cell reselection in advance after detecting RLF, and simultaneously triggers NAS recovery procedures when configured to do so. This preliminary action ensures the UE is already in a suitable cell before downlink data needs to be delivered, reducing the delivery delay while maintaining reliable radio link recovery
3Reliability
If the network pages the UE for downlink data after RLF, then data delivery is achieved, but service interruption time increases due to paging procedure delays
Solution Approach 1:
The UE proactively triggers NAS recovery procedures in advance when configured to do so, rather than waiting for network paging. This preliminary action re-establishes the connection before downlink data needs to be delivered, eliminating the need for paging procedures and reducing service interruption time while ensuring reliable data delivery
Data Source
AI summary
A method of operating a communication system is provided. The communication system comprises a NetWork (NW) and User Equipment (UE), a Non Access Stratum (NAS) via which the NW and UE communicate with each other, and an Access Stratum (AS) providing a physical connection to enable the NAS communication between the NW and UE to be achieved, the physical connection including a wireless radio link to the UE. The method includes sending information from the NW to the UE to determine at least one action of the UE in response to a failure of a radio link to the UE, detecting a Radio Link Failure (RLF), in response to the detecting of the RLF, deciding on an action to be performed by the UE according to the received information, and performing, by the UE, the decided action.