MCPTT Group Identity Concealment via Pseudonyms

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Solution Overview

Problem

Current mission-critical push-to-talk (MCPTT) services in multimedia broadcast multicast services (MBMS) lack effective mechanisms to conceal MCPTT group identifiers, allowing unauthorized user equipment (UEs) within the service area to detect active groups, compromising security and privacy.

Innovation Solution

The use of MCPTT group pseudonyms instead of actual group identifiers in MBMS subchannel control messages, where pseudonyms are generated based on specific parameters, such as group-specific secret parameters and group master keys, and sent via group notification messages or encrypted messages, ensuring only group members can identify intended messages.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If MCPTT group identifiers are transmitted in MBMS subchannel control messages, then group members can correctly receive and process messages, but non-member UEs can detect and identify active MCPTT groups, compromising security and privacy

Engineering Contradiction:
Improvemessage delivery accuracyVSAvoidunauthorized detection of group identity
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent introduces an MBMS bearer identifier as an intermediary element that replaces the direct use of MCPTT group identifier in control messages. This intermediary allows message routing to group members through the bearer association while concealing the actual group identity from non-members, thus resolving the contradiction between reliable message delivery and security/privacy protection

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent changes the parameter used in control messages from the actual MCPTT group identifier to an MBMS bearer identifier. This parameter substitution maintains the functionality of message delivery (since members can map bearer ID to their group) while eliminating the security vulnerability of exposing group identities to non-members

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentUS11564087B2Mission-critical push-to-talk
Publication Date: 2023.01.24 TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)
  • US11564087B2 patent drawing
  • US11564087B2 patent drawing
  • US11564087B2 patent drawing

AI summary

A user equipment is configured for concealment of a mission-critical push-to-talk (MCPTT) group identity in multimedia broadcast multicast services (MBMS). The UE is configured in particular to receive an indication of an MCPTT group pseudonym (7) which is a pseudonym for an MCPTT group identity (11) that identifies an MCPTT group of which the UE is a member. The UE may for example receive this indication from a group management server (GMS) or an MCPTT server. The UE in some embodiments may determine whether received control signalling (e.g., an MBMS subchannel control message) is for the MCPTT group of which the UE is a member, by determining whether the control signaling includes the MCPTT group pseudonym (7).