Temporary Identifier Paging for User Equipment Privacy
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Solution Overview
Problem
Current 4G/LTE and legacy communication systems face security threats due to the use of permanent identifiers for user equipment, allowing fake base stations and passive/active listeners to track user location with reasonable accuracy, which is not adequately addressed.
Innovation Solution
Implementing a paging process that exclusively uses temporary identifiers, such as the S-TMSI, instead of permanent identifiers like IMSI, to prevent user tracking and enhance privacy by avoiding the use of IMSI in paging messages, ensuring that only temporary identifiers are used for user equipment in idle mode.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If permanent identifiers (IMSI) are used in paging messages, then user equipment can be reliably identified and paged, but user location can be tracked by fake base stations and passive/active listeners
Solution Approach 1:
The patent uses temporary identifiers (S-TMSI) instead of permanent identifiers (IMSI) for paging user equipment. These temporary identifiers are short-lived and frequently updated, making them useless for long-term tracking. When a UE is paged using S-TMSI, the identifier becomes outdated and is replaced with a new one in subsequent paging cycles, effectively preventing attackers from tracking user location over time while maintaining reliable identification during each paging instance.
Solution Approach 2:
The patent changes the identification parameter from permanent (IMSI) to temporary (S-TMSI) for paging operations. This parameter change ensures that the identifier used for paging is frequently updated and has limited validity period. The network can reliably identify and page UEs using S-TMSI, but the temporary nature of this identifier prevents long-term tracking by fake base stations and listeners, as the identifier changes between paging cycles.
2Object-affected harmful factors
If temporary identifiers (S-TMSI) are used in paging messages, then user tracking is prevented, but identifier validation and mapping complexity increases
Solution Approach 1:
The patent performs preliminary mapping of temporary identifiers (S-TMSI) to permanent identifiers (IMSI) and stores this mapping information in the network's memory before paging operations. When a UE attaches to the network, the network establishes and stores the correspondence between S-TMSI and IMSI. During paging, the network can validate the temporary identifier against stored mapping information, eliminating the need for complex real-time validation and simplifying the paging process while maintaining security.
Solution Approach 2:
The patent introduces a mapping mechanism that acts as an intermediary between temporary identifiers (S-TMSI) and permanent identifiers (IMSI). This mapping table stored in network memory allows the system to work with temporary identifiers for paging operations while maintaining the ability to reference permanent identifiers when needed. The mapping intermediary simplifies identifier management by decoupling the paging process from direct IMSI handling, reducing complexity while maintaining security.
Data Source
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AI summary
Techniques are provided for protecting the privacy of user equipment during paging operations in a communication system. A method includes determining (600) at a mobility management element of a communication system that a paging operation is to be initiated for given user equipment. The method further includes restricting (602) the paging operation between the mobility management element and the given user equipment to use of a temporary identifier for the given user equipment. By not using a permanent identifier of the given user equipment during paging operations, the given user equipment is effectively non-trackable by malicious base stations and active/passive listeners.