Interference Robustness and Security of Impulse-Radio Ultra-Wide Band Networks

摘要: In this thesis we study Impulse-Radio Ultra-Wide Band (IR-UWB), a physical layer radio technology offering many features that make it promising choice for future short-range wireless networks. The challenges in such networks are many, ranging from the cost-complexity constraints of devices, through presence interference created by other users, up to stringent security requirements imposed sensitive applications. Our main goal is understand and show how low-complexity IR-UWB receiver can be designed able cope with difficult environment will face Although systems promise provide solution some above-mentioned challenges, not panacea: More often than not, live its promises only if entire system carefully designed. One example robustness concurrent which topic first part thesis. Short-range expected self-organized uncoordinated rather centrally organized. This turn leads uncontrolled due transmissions devices. Thanks large bandwidth, combined low duty-cycle transmissions, should theory accommodate number users while keeping multi-user (MUI) levels low. We that, properly addressed, MUI severely affect performance an receiver, making benefit void. especially true complexity architectures, as popular non-coherent energy-detection used. Further, affects all aspects packet reception appropriate algorithms deal thus required at every level. crucial step receive data signal acquisition. present robust algorithm allows reliable acquisition MUI, even near-far scenarios. After acquisition, performs phase channel estimation. Channel estimation particular importance mitigation: distinguish user interest MUI. case receivers compliant standard IEEE 802.15.4a, challenging because signalling structure changes within packet. introduce novel takes peculiarity into account design 802.15.4a final receiving demodulation decoding payload. adaptive thresholding scheme uses state information, obtained during estimation, yield very good against also more sophisticated based on statistical modeling they additional increase second investigate clock-offset tracking receivers. Clock-offset needed oscillators driving clocks average quality best. resulting desynchronization between transmitter may lead huge degradation To overcome sensitivity clock offsets, constructed around Radon transform, image processing tool traditionally used detect line images. fully compatible standard, does hardware reduces loss offsets marginal third thesis, look viewpoint security. evaluate what extent vulnerable distance-decreasing attacks layer. These target mechanism two devices estimate their mutual distance. Commonly, secured secure protocols employing cryptographic mechanisms guarantee estimated distance upper-bound actual However, new breed bypasses these mechanisms, introduced higher communication layers, directly attacking Understanding impact utmost importance: high precision capabilities natural candidate applications, has been specifically ranging. analysis shows automatically attacks. find mandatory modes no countermeasures place, external attacker decrease measured one hundred meters probability.