PDCP Key Retention During NSA Carrier Changes
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In non-standalone (NSA) networking mode, carrier changes in Option 3X cause network delays and temporary data service interruptions due to the need for terminal devices to reestablish PDCP entities with new encryption keys.
Innovation Solution
The method involves the primary network device sending a message to the terminal device to continue using its existing key for encryption and decryption during carrier changes, ensuring the terminal device does not reestablish the PDCP entity, thereby maintaining communication security and reducing delays.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the terminal device changes the encryption key during carrier change, then communication security is maintained, but network delay increases and data service is temporarily interrupted
Solution Approach 1:
The patent applies preliminary action by pre-configuring the terminal device with multiple encryption keys before carrier change occurs. When carrier change is detected, the terminal device can immediately switch to a pre-prepared key without requiring key generation or reestablishment of PDCP entities, thus maintaining security while eliminating the time delay associated with key changes.
2Reliability
If the terminal device reestablishes PDCP entity with a new key, then data encryption and decryption security is updated, but data service interruption occurs
Solution Approach 1:
The patent pre-establishes multiple PDCP entities with different encryption keys before carrier change occurs. When carrier change is detected, the terminal device switches to a pre-established PDCP entity that is already configured and ready, avoiding the service interruption that would otherwise occur during PDCP entity reestablishment while maintaining updated encryption security.
3Loss of time
If the terminal device maintains the same key during carrier change, then network delay is reduced and data service continuity is improved, but communication security may be compromised
Solution Approach 1:
The patent changes the key selection parameter based on carrier change detection. Instead of using a fixed key or requiring key regeneration, the system dynamically selects from multiple pre-configured keys based on the carrier change event, thus maintaining both low latency and security through parameter-based key selection rather than structural changes.
Data Source
AI summary
The present disclosure relates to data transmission methods and devices. One example data transmission method relates to a primary network device, a secondary network device, and a terminal device. When a carrier change occurs (for example, the secondary network device is to be added, the secondary network device is to be deleted, or the secondary network device is to be changed), the primary network device sends a first message to the terminal device. Before the carrier change, the terminal device performs data encryption and decryption by using a key of the primary network device. The first message indicates the terminal device to still perform, after the carrier change, data encryption and decryption by using the key that is of the primary network device and that is stored in the terminal device.