Wireless Security Key Update via Consistent PCI and ARFCN

The patent applies local quality by differentiating the treatment of different cell groups within the handover message. Specifically, it identifies whether cells belong to master cell groups or secondary cell groups, and applies different key derivation rules accordingly - using the first ARFCN for master cell groups and the second ARFCN for secondary cell groups. This localized differentiation resolves the contradiction by ensuring each cell group receives appropriate key management while maintaining overall system adaptability

The patent segments the handover control message processing into distinct parts: identifying the first ARFCN and first PCI for master cell group key derivation, and identifying the second ARFCN and second PCI for secondary cell group key derivation. This segmentation allows independent and correct key derivation for each cell group, preventing security key mismatches while supporting multiple PCIs and ARFCNs in the overall handover process

The patent implements preliminary action by performing key derivation calculations before the actual handover execution. The terminal device derives the target cell group key and target cell key in advance based on the received handover control message, ensuring that correct keys are ready before service transition. This preliminary key preparation prevents service breakdowns while maintaining fast handover execution

The patent incorporates feedback mechanisms where the terminal device verifies the derived keys against the handover control message parameters. By checking consistency between the first ARFCN/first PCI and second ARFCN/second PCI with the respective cell groups, the system provides feedback validation that prevents key mismatches while enabling rapid handover completion