Primary Cell Change Without Handover in 5G Networks
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Solution Overview
Problem
In wireless communication systems, particularly in next-generation networks like NR, the process of primary cell change is inefficient, leading to prolonged data interruption due to the requirement of a handover procedure, which can take around 40 ms and is undesirable, especially with high frequency bands and beamforming.
Innovation Solution
A method and device for detecting whether layer 2 context is kept and/or serving secondary cells remain for a primary cell change, allowing for the configuration and transmission of a message indicating the primary cell change without the need for a handover procedure, by including security information, RLC/MAC reconfiguration, or ID information based on the detected conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If handover procedure is used for primary cell change, then security and reliability are ensured, but data transmission interruption time increases to around 40 ms
Solution Approach 1:
The patent segments the primary cell change process into two distinct modes: handover-based change (for security-critical scenarios) and non-handover-based change (for latency-critical scenarios). By dividing the monolithic handover procedure into optional components, the system can selectively apply security procedures based on service requirements, thereby reducing unnecessary interruption time while maintaining reliability where needed.
Solution Approach 2:
The patent applies partial action by allowing the primary cell change to proceed without the complete handover procedure in certain cases. Specifically, the security key derivation and reconfiguration steps can be partially omitted or deferred when the radio link quality degradation is not severe, enabling faster cell switching while maintaining adequate security through alternative mechanisms.
2Reliability
If frequent primary cell changes are performed in next generation networks, then radio link quality is optimized, but data transmission interruption occurs more frequently
Solution Approach 1:
The patent introduces dynamic adaptation by allowing the primary cell change mechanism to adjust its behavior based on real-time radio conditions and service requirements. The system dynamically selects between handover-based and non-handover-based change modes, and adjusts the threshold for triggering primary cell changes, thereby optimizing the balance between maintaining radio link quality and ensuring data transmission continuity.
Solution Approach 2:
The patent changes key parameters of the primary cell change procedure, including the threshold for triggering cell changes, the security verification requirements, and the reconfiguration timing. By adjusting these parameters dynamically based on service type and radio conditions, the system can tolerate more frequent cell changes in some scenarios while maintaining data transmission continuity in others.
3Reliability
If handover procedure with security key derivation is executed, then security is maintained, but procedure complexity and time consumption increase
Solution Approach 1:
The patent segments the security procedures into essential and optional components. The essential components (such as basic authentication) are always executed, while optional components (such as full security key derivation and reconfiguration) are executed only when security risks are detected or service requirements demand it. This segmentation reduces the average procedure complexity while maintaining security when needed.
Solution Approach 2:
The patent employs lightweight security mechanisms for temporary or low-risk cell changes, using simplified verification methods instead of full security key derivation. These lighter security objects are disposable and context-dependent, providing adequate security for brief or low-risk operations without the overhead of complete security procedures.
Data Source
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AI summary
Embodiments of the disclosure generally relate to primary cell change. A network device detects whether layer 2 context being kept and/or one or more serving secondary cells remain for a primary cell change for a terminal device. Then, the network device configures a message indicating the primary cell change based on the detecting and transmits the message to the terminal device. The time period of primary cell change can be reduced efficiently and the data transmission during the primary cell change can be optimized.