Non-Public Network Access Signaling for Hidden CAG Identity
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Solution Overview
Problem
The RRC setup complete message in network sharing scenarios is not encrypted, exposing the identity of a CAG network and leading to security risks.
Innovation Solution
A method where a terminal device generates first indication information to indicate multiple non-public networks, including a first non-public network it intends to access, such that the specific network cannot be determined from the indication information alone, enhancing security by preventing exposure of the user's identity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the terminal device reports the CAG network identity through the RRC setup complete message, then the base station can learn the connection status and allocate resources properly, but the message is not encrypted and the network identity is exposed to security risks
Solution Approach 1:
The patent segments the network identity information into two parts: a public network identity (PLMN ID) that can be openly reported, and a private CAG network identity that remains hidden. The terminal device reports only the PLMN ID in the RRC setup complete message, while the base station infers the CAG network identity through internal mapping tables that associate PLMN IDs with specific CAG networks. This segmentation allows connection status reporting while preventing exposure of the actual CAG network identity.
Solution Approach 2:
The patent introduces an intermediary mechanism in the form of a mapping table stored in the base station that links public PLMN IDs to private CAG network identities. When the terminal device reports a PLMN ID, the base station uses this intermediary mapping table to determine the actual CAG network without the terminal device explicitly revealing it. This intermediary layer protects the CAG network identity from being exposed in the open RRC message while still enabling proper network identification and resource allocation.
2Measurement precision
If the terminal device reports specific network identity, then the base station can accurately identify the network for resource allocation, but user privacy is exposed and interception risks increase
Solution Approach 1:
The patent segments network identification into public and private components. The terminal device reports only the public PLMN ID portion, which provides sufficient information for the base station to identify the general network context through the mapping table, without exposing the private CAG network identity. This segmentation maintains functional network identification accuracy while protecting user privacy by hiding the specific CAG network identity from potential interceptors.
3Object-affected harmful factors
If the RRC setup complete message is encrypted, then network security is improved, but the base station cannot efficiently determine connection status for resource allocation
Solution Approach 1:
The patent applies segmentation by separating the identification function into two layers: the public PLMN ID layer that can be openly transmitted and processed for connection status determination, and the private CAG network identity layer that remains protected. This allows the base station to efficiently determine connection status and allocate resources based on the openly reported PLMN ID, while the actual CAG network identity remains secure. The mapping table enables this efficient resource allocation without requiring encryption of the entire message or exposure of sensitive identity information.
Data Source
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AI summary
This application provides a communication method, a communications apparatus, and a communications system. The method includes: A terminal device generates first indication information, where the first indication information is used to indicate a plurality of non-public networks, the plurality of non-public networks include a first non-public network, and the first non-public network is a network that the terminal device requests to access; and the terminal device sends the first indication information to an access network device. In this application, the first indication information is used to indicate the plurality of non-public networks including the first non-public network, and which one of the plurality of non-public networks is the first non-public network cannot be determined by using only content of the first indication information. In this way, even if the first indication information is intercepted, the specific network that the terminal device requests to access cannot be determined, so that an identity of a user is not exposed, and use security of the network is improved.