RAN UE Identifier Reallocation for RNTI Privacy Protection

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Solution Overview

Problem

Wireless communication systems face challenges in maintaining user equipment (UE) privacy due to the potential for long-term use of radio network temporary identifiers (RNTIs), which can be exploited by attackers to track UE activity, undermining security.

Innovation Solution

The system reallocates RNTIs, such as C-RNTIs, by providing an indication for a UE to switch to a new identifier, using methods like RRC messages, MAC CE messages, or PRACH procedures, potentially expanding the identifier size to reduce collision risks and enhance privacy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the same RNTI is used for long-term communication, then communication efficiency is maintained, but UE privacy is compromised due to identifier tracking

Engineering Contradiction:

Improvecommunication efficiencyVSAvoidUE privacy vulnerability

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent implements dynamic RNTI allocation where the network can assign different RNTIs to the same UE at different times. The network node maintains mapping information between temporary identifiers and actual UEs, allowing it to switch RNTIs periodically or based on specific triggers, thereby preventing long-term tracking while maintaining communication efficiency

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent changes the identifier parameter by introducing multiple RNTI values that can be assigned to a single UE. Instead of using one fixed RNTI, the system varies the RNTI parameter over time through network-controlled reallocation, which preserves communication efficiency while mitigating privacy risks

Inventive Principle:

Principle #35Parameter changes

2Object-affected harmful factors

If RNTI reallocation is implemented frequently, then UE privacy is enhanced, but signaling overhead increases

Engineering Contradiction:

Improveidentifier collision riskVSAvoidsignaling overhead

Core Design Contradiction:

Object-affected harmful factorsVSLoss of information

Solution Approach 1:

The patent applies partial reallocation by only changing RNTIs when necessary rather than continuously. The network can trigger reallocation based on timers, security policies, or detection of potential collisions, performing the action partially (only when needed) to reduce unnecessary signaling overhead while still providing privacy protection

Inventive Principle:

Principle #16Partial or excessive action

Solution Approach 2:

The system implements feedback mechanisms where the network monitors RNTI usage patterns and triggers reallocation based on detected conditions such as potential collisions or security thresholds. This feedback-driven approach allows the system to allocate new RNTIs selectively rather than continuously, reducing signaling overhead while maintaining privacy

Inventive Principle:

Principle #23Feedback

Data Source

PatentUS20250386182A1Radio access network (RAN) user equipment (UE) identifier privacy

Publication Date: 2025.12.18 QUALCOMM INC

AI summary

Disclosed are systems and techniques for wireless communications. For instance, a process can include communicating with a network node based on first radio network temporary identifier (RNTI), determining to switch to a second RNTI, and communicating with the network node based on the second RNTI.