Constellation Phase Rotation for Physical-Layer Signal Security
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Solution Overview
Problem
Existing air interface security mechanisms in cellular networks are inadequate at the physical layer, particularly for new applications like positioning and sensing, as high-layer security technologies struggle to address vulnerabilities in wireless channel security.
Innovation Solution
Implement phase rotation encryption using diagonal unitary matrices to encrypt and decrypt constellation points based on legitimate channel information, ensuring only authorized receivers can decode the signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If high-layer security technologies are deployed at PDCP layer or higher, then security of information transmission is improved, but security vulnerabilities at physical layer remain unresolved
Solution Approach 1:
The patent applies preliminary action by performing encryption at the physical layer before signal transmission. The constellation points are encrypted using phase rotation based on channel state information before being modulated and transmitted, ensuring security is established at the earliest possible stage rather than relying solely on higher-layer security mechanisms.
Solution Approach 2:
The patent uses channel state information as an intermediary to enable encryption. The legitimate channel's CSI is used to generate encryption keys through phase rotation, creating a security mechanism that leverages the channel itself as a mediator for secure communication without requiring separate key distribution mechanisms.
2Reliability
If phase rotation encryption is applied to constellation points, then security against eavesdroppers is improved, but signal processing complexity increases
Solution Approach 1:
The patent changes the phase parameter of constellation points through rotation based on channel state information. This parameter change serves as the encryption mechanism, where the phase angle is modified according to the legitimate channel's CSI, creating secure transmission without requiring complex cryptographic algorithms.
Solution Approach 2:
The system uses its own channel state information to generate the encryption key, making the channel itself serve the dual purpose of signal transmission and key generation. This self-service approach eliminates the need for separate key distribution infrastructure and reduces overall system complexity.
3Reliability
If constellation points are encrypted using legitimate channel information, then only authorized receivers can decode signals, but eavesdroppers face difficulty in decryption
Solution Approach 1:
The patent applies local quality by using the specific characteristics of the legitimate channel's CSI at the receiver location to enable decryption. The encryption is localized to the legitimate channel's properties, meaning only the receiver with matching channel knowledge can decrypt, while eavesdroppers with different channel characteristics cannot.
Solution Approach 2:
The patent creates asymmetry between the legitimate channel and eavesdropping channel. The encryption key is derived from the legitimate channel's CSI, creating an asymmetric situation where the legitimate receiver has the correct key while eavesdroppers, experiencing different channel conditions, cannot derive the correct decryption key.
4Reliability
If security mechanisms are deployed before security context activation, then pre-transmission security is improved, but existing mechanisms lack physical layer protection
Solution Approach 1:
The patent implements preliminary action by establishing security mechanisms before security context activation and before data transmission. The phase rotation encryption is applied to constellation points prior to modulation and transmission, ensuring that even pre-transmission signals are protected at the physical layer.
Solution Approach 2:
The patent introduces dynamics by making the encryption key adaptive to channel conditions. The phase rotation amount is determined based on real-time channel state information, allowing the security mechanism to adapt to changing channel conditions rather than using static encryption keys.
Data Source
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AI summary
This application relates to the field of communication technologies, and provides a communication method and an apparatus, to improve security of information transmission at a physical layer. In the method, a transmit end may encrypt a physical-layer signal, for example, rotate, using a first key, a phase of a second constellation point that is in a second constellation diagram and that carries data, to obtain a first constellation point in a first constellation diagram. Correspondingly, a receive end may decrypt a received physical-layer signal, for example, decrypt a third constellation point in a received third constellation diagram using a second key, to obtain a fourth constellation point that is in a fourth constellation diagram and that carries the foregoing data. In this case, eavesdroppers cannot directly decrypt the intercepted physical-layer signal, and therefore unable to obtain the corresponding data. This can avoid data leakage and improve physical layer transmission security.