Random Subcarrier Selection With Artificial Signals for Wireless PLS
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Solution Overview
Problem
Existing physical layer security methods face challenges such as high power consumption, peak-to-average power ratio issues, spectral efficiency loss, and vulnerability to co-located attacks and temporal correlation in wireless communication, particularly in the presence of passive eavesdroppers.
Innovation Solution
A novel method involving channel-based joint random subcarrier selection and artificial signal design, where the strongest subcarriers in each window are selected for secret sequence extraction, and an artificial signal is added to confuse eavesdroppers, ensuring secure communication without conventional cryptography.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If jamming and artificial noise techniques are used to provide security, then security level is improved, but power consumption increases and peak-to-average power ratio issues occur
Solution Approach 1:
The patent segments the frequency spectrum into multiple subcarriers and selectively applies artificial noise only to specific subcarriers experiencing deep fading, rather than applying noise across the entire bandwidth. This segmentation allows security enhancement while minimizing overall power consumption and avoiding excessive PAPR issues.
Solution Approach 2:
The patent applies artificial noise locally only to subcarriers in deep fading conditions, rather than uniformly across all subcarriers. This local application maintains security where needed while reducing overall power consumption and avoiding PAPR problems in other subcarriers where noise is not applied.
2Reliability
If noise is added only on subcarriers in deep fading and strong subcarriers are used for data transmission, then security is improved, but spectral efficiency is reduced due to not using the whole band
Solution Approach 1:
The patent divides the frequency band into multiple subcarriers and applies different treatments to different segments: artificial noise is applied to subcarriers in deep fading for security, while strong subcarriers are used for data transmission to maintain spectral efficiency. This segmentation resolves the contradiction by optimizing each segment's function.
Solution Approach 2:
The patent makes the subcarrier system multi-functional by allowing different subcarriers to serve different purposes simultaneously: some subcarriers provide security through artificial noise, while others provide high-rate data transmission. This universal approach enables the system to achieve both security and spectral efficiency.
3Reliability
If secret sequence is extracted from wireless channel using TDD mode, then physical layer security is achieved, but temporal correlation problem occurs as channel does not change much over time
Solution Approach 1:
The patent introduces dynamic subcarrier selection based on real-time channel conditions, where the set of subcarriers used for secret sequence extraction changes according to fading patterns. This dynamic approach reduces temporal correlation because the selected subcarriers vary over time even when the overall channel remains relatively stable.
Solution Approach 2:
The patent transitions from extracting secret sequences solely in the time domain to extracting them in the frequency domain by selecting specific subcarriers. This dimensional change from time-based to frequency-based secret sequence extraction provides new degrees of freedom and reduces temporal correlation while maintaining physical layer security.
4Reliability
If conventional cryptography based security solutions are used, then security is provided, but key sharing and key management become challenging in future wireless networks with large number of nodes
Solution Approach 1:
The patent enables each wireless node to autonomously generate its own secret sequences by exploiting its unique channel characteristics and subcarrier selection patterns. This self-service approach eliminates the need for centralized key management and sharing infrastructure, allowing nodes to independently establish secure communications even in large-scale networks.
Solution Approach 2:
The patent changes the fundamental parameter for security from shared cryptographic keys to channel-dependent secret sequences generated locally at each node. This parameter change from key-based security to channel-based security eliminates key management complexity while maintaining strong security guarantees.
Data Source
AI summary
In the area of Joint Random Subcarrier Selection and Channel-Based Artificial Signal Design Aided PLS, a method for providing physical layer security (PLS) depending on the randomness of wireless channel is proposed. Specifically, a channel-based joint random subcarrier selection and artificial signal design are introduced to protect the communication in the presence of a passive eavesdropper which can be even stronger than the legitimate receiver. Our analysis assumes a window-based subcarrier selection method in which the strongest subcarriers in each window are selected. Chosen subcarriers are considered for secret sequence extraction. The generated channel dependent secret sequence is used for both random subcarrier selection and artificial signal design. We evaluate the efficiency of the proposed method through some representative metrics, such as secret sequence disagreement rate (SSDR), throughput and bit error rate (BER), in both perfect and imperfect channel estimation cases. Simulation results are presented and insightful discussions are drawn.