RRC Re-establishment Using Unique MAC-I for Unauthenticated Calls
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In LTE networks, unauthenticated calls face challenges during Radio Resource Control (RRC) Connection Re-establishment due to the inability to uniquely identify Mobile Equipment (ME) when using the Null Integrity algorithm, leading to potential interruptions and dropped calls, especially in scenarios like emergency situations where multiple MEs have similar radio conditions and shared identifiers.
Innovation Solution
A method is introduced to calculate a Message Authentication Code (MAC-I) for unauthenticated calls using a MAC algorithm that depends on the Cell-Radio Network Temporary Identifier (C-RNTI), Physical Cell Identity (PCI), and Cell Identity, allowing for unique identification and verification of MEs during RRC Connection Re-establishment, even when the Null Integrity algorithm is used.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the Null Integrity algorithm (EIA0) is used for unauthenticated calls, then the call setup is simplified and faster, but the ME cannot be uniquely identified during RRC Connection Re-establishment, causing call interruptions
Solution Approach 1:
The patent changes the parameter used for identification from the standard shortMAC-I (which is all zeros with EIA0) to a newly defined MAC-I that is calculated using a different algorithm (EIA1, EIA2, or EIA3) that produces non-zero, unique values. This parameter change allows unauthenticated calls to maintain connection re-establishment capability while keeping the simplified call setup process.
2Productivity
If multiple MEs have the same C-RNTI and PCI in neighboring cells, then resource allocation is efficient, but ME identification becomes ambiguous during re-establishment, leading to call drops
Solution Approach 1:
The patent introduces MAC-I as an intermediary identifier that mediates between the non-unique C-RNTI/PCI combination and the need for unique ME identification. The MAC-I, calculated using integrity protection algorithms, serves as a unique fingerprint for each ME even when C-RNTI and PCI are shared, allowing the target cell to correctly identify and verify the ME during re-establishment.
3Speed
If the shortMAC-I is used for ME verification, then the verification process is fast, but it provides no unique identity when EIA0 is used, causing verification failures
Solution Approach 1:
The patent replaces the shortMAC-I parameter with MAC-I for unauthenticated calls. While shortMAC-I is calculated using EIA0 (producing all zeros), MAC-I is calculated using EIA1, EIA2, or EIA3 which produce non-zero, unique values. This parameter substitution maintains the fast verification process while ensuring verification success by providing meaningful unique identifiers.
Data Source
AI summary
The present invention relates to Radio Resource Control, RRC Connection re-establishments of unauthenticated calls or sessions between MEs, and one or more eNodeBs. By making use of the Cell Identity of the cell in which a ME having radio connection malfunction resides, in the calculation of a Message Authentication Code for data Integrity, MAC-I a ME unique MAC-I can be calculated which is used for the identification and verification of MEs by a target base station such as a eNodeB, in RRC Connection re-establishment of unauthenticated calls.