NOMA Downlink Phase Shifting for Internal and External Eavesdroppers
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Solution Overview
Problem
Existing Non-Orthogonal Multiple Access (NOMA) systems face significant security risks from both internal and external eavesdroppers, particularly in challenging environments like IoT and mMTC networks, where conventional security mechanisms degrade legitimate user performance or require additional resources.
Innovation Solution
A novel secure NOMA scheme that induces a phase shift in each user's symbol based on their instantaneous channel phase, ensuring only the intended user can decode the data without affecting others, and does not rely on identifying the eavesdropper.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional cryptography is used for security, then data confidentiality is protected, but it cannot address physical layer security risks in NOMA systems
Solution Approach 1:
The patent introduces channel phase as an intermediary element that mediates between the transmitted signal and the receiver. By encoding data with user-specific channel phase information, the system creates a security layer that requires knowledge of the channel characteristics to decode, thus addressing physical layer security risks while maintaining data confidentiality
Solution Approach 2:
The patent changes the parameter used for security from cryptographic keys to channel phase characteristics. By exploiting the random and independent channel characteristics, the system induces different phase shifts in each user's symbol, making it impossible for eavesdroppers to decode signals without knowing the specific channel phase of each user
2Object-affected harmful factors
If artificial noise is used to degrade eavesdropper performance, then external eavesdropping is mitigated, but it affects legitimate user performance and requires additional resources
Solution Approach 1:
The patent applies local quality by making the security mechanism user-specific through channel phase encoding. Each user's signal is encoded with their unique channel phase information, creating a localized security property that protects each user individually without requiring global artificial noise that would affect all users
Solution Approach 2:
The system uses the existing channel characteristics as the security mechanism, making the channel itself serve the security function. This self-service approach eliminates the need for additional artificial noise resources, as the random and independent channel characteristics naturally provide the security differentiation needed
3Productivity
If successive interference cancellation (SIC) is used in PD-NOMA, then multiple users can share the same resources, but internal users can eavesdrop on other users' signals
Solution Approach 1:
The patent applies preliminary action by encoding each user's signal with their channel phase information before transmission. This pre-encoding security measure ensures that even if internal users successfully decode other signals through SIC, they cannot interpret the data without knowledge of the specific channel phase, thus preventing internal eavesdropping while maintaining NOMA functionality
4Object-affected harmful factors
If beamforming and artificial noise are combined to secure NOMA, then external eavesdropping is degraded, but the system complexity and resource requirements increase
Solution Approach 1:
The patent extracts the security function from complex beamforming and artificial noise mechanisms and implements it through simple channel phase encoding. By taking out the essential security requirement (user-specific differentiation) and implementing it through the naturally available channel phase, the system achieves security against external eavesdroppers without increasing system complexity or resource requirements
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The scheme provides robust security against both internal and external eavesdroppers without additional time or resource consumption, maintaining legitimate user performance and supporting various network conditions.
Implementation Method 1
the proposed method exploits the random and independent channel characteristics to induce a different phase shift in each user's symbol
Data Source
AI summary
Disclosed is a secure scheme that incorporates both internal and external eavesdroppers to secure all users' links in the downlink PD-NOMA. In particular, the proposed scheme implies that the BS induces a phase shift in each user's symbol based on its corresponding instantaneous channel phase. The phase shift of each user is restricted such that the original symbol is moved to the location of another symbol in the constellation diagram. Therefore, as each user is aware of its instantaneous channel phase only, it will be able to recover the actual phase of its corresponding symbol. Thus, the proposed scheme does not only protect the data against eavesdroppers, but it also guarantees confidentiality and privacy against all other users.