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A master's thesis from Aalborg University
Book cover


Radio security potential in WLAN

Authors

;

Term

10. term

Publication year

2007

Pages

103

Abstract

Trådløs kommunikation kan aflyttes, fordi signaler sendes gennem luften. Dette projekt undersøger, hvordan man kan øge sikkerheden allerede i det fysiske lag af systemet, så løsningen er indbygget, robust og usynlig for brugeren. Vi anvender singulærværdidekomposition (SVD) i et multiple-input multiple-output (MIMO) system mellem et adgangspunkt og en målbruger og ser samtidig på, hvordan en aflytter potentielt kan opfange signalet. Projektet har tre hoveddele: - Vurdere SVD-ydelsen i et smalbåndet MIMO-link og forsøge at øge målbrugerens kapacitet ved at ændre effektallokering (ens fordeling vs. vandfyldning, hvor mere effekt lægges på de bedste kanaler). - Undersøge systemets sikkerhedsrobusthed over for aflytning ved at modellere aflytterens muligheder, herunder avanceret behandling som SVD og antennekombinering som Equal Gain Combining (EGC) og Maximum Ratio Combining (MRC), dvs. metoder til at sammenlægge signaler fra flere antenner for bedre modtagelse. - Foreslå et kompromis mellem høj kapacitet for målbrugeren og kontrolleret forringelse af signalet for uvedkommende, så aflytteren får vanskeligere ved at opfange og forstå data.

Wireless signals can be intercepted because they travel through the air. This project explores how to strengthen security at the physical layer of the system so that protection is built-in, robust, and transparent to the user. We apply singular value decomposition (SVD) in a multiple-input multiple-output (MIMO) system between an access point and the intended user, and we study how an eavesdropper might receive the signal. The work has three main parts: - Evaluate SVD performance in a narrowband MIMO link and try to increase the target user’s capacity by changing power allocation (uniform versus water-filling, which puts more power on the strongest channels). - Assess security robustness against eavesdropping by modeling what an eavesdropper can do, including advanced processing such as SVD and antenna combining techniques like Equal Gain Combining (EGC) and Maximum Ratio Combining (MRC), i.e., ways to merge signals from multiple antennas to improve reception. - Propose a trade-off between high capacity for the intended user and controlled signal degradation for unintended listeners, making it harder for an eavesdropper to capture and interpret the data.

[This abstract was generated with the help of AI]