The United States Federal Communications Commission (FCC) in its recent report and order has prescribed the creation of Citizens Broadband Radio Service (CRBS) in the 3.5 GHz band to enable sharing between wireless broadband devices and incumbent radar systems. This sharing will be enabled by use of geolocation database with supporting infrastructure termed as Spectrum Access System (SAS). Although using SAS for spectrum sharing has many pragmatic advantages, it also raises potentially serious operational security (OPSEC) issues. In this thesis, we explore OPSEC, location privacy in particular, of incumbent radars in the 3.5 GHz band. First, we show that adversarial secondary users can easily infer the locations of incumbent radars by making seemingly innocuous queries to the database. Then, we propose several obfuscation techniques that can be implemented by the SAS for countering such inference attacks. We also investigate obfuscation techniques' efficacy in minimizing spectral efficiency loss while preserving incumbent privacy.
Recently, the 3GPP Rel.13 has specified a new standard to provide wide-area connectivity for IoT, termed as Narrowband IoT (NB-IoT). NB-IoT achieves excellent coexistence with legacy mobile standards, and can be deployed in any of the 2G/3G/4G spectrum (450 MHz to 3.5 GHz). Recent industry efforts show deployment of IoT networks in unlicensed spectrum, including shared bands (e.g., 3.5 GHz band). However, operating NB-IoT systems in the 3.5 GHz band can result in significant BLER and coverage loss. In this thesis, we analyse results from extensive experimental studies on the coexistence of NB-IoT and radar systems, and demonstrate the coverage loss of NB-IoT in shared spectrum. / Master of Science / Spectrum sharing has been viewed by spectrum regulators and industry stakeholders as the most viable solution to overcome the spectrum congestion and to enable next generation wireless networks. Towards this end, the Federal Communications Commission in the United States has prescribed rules to enable sharing between incumbent radars and broadband wireless networks in the 3.5 GHz band. This sharing however will be enabled geolocation databases and supporting infrastructure known as Spectrum Access System, which are prone to privacy attacks by malicious secondary users. Preserving privacy of incumbent systems is vital as they are mostly military radars. In this thesis, we demonstrate such attacks and later propose efficient techniques to preserve the privacy of the incumbent systems while enabling better spectrum utilization.
The phenomenal growth in smarter end-user devices and machine-to-machine (M2M) connections is a clear indicator of the growth of Internet of Things (IoT), and growing importance of wide area IoT networks. Recently, the telecommunications standard development body, 3GPP, has defined Narrowband IoT (NB-IoT) optimized for IoT. Also, NB-IoT has many features common to LTE, and it is likely that NB-IoT will also be deployed in bands where LTE will be deployed, including shared bands (e.g., 3.5 GHz band). However, NB-IoT systems that operate in the 3.5 can be prone to harmful radar interference and directly impact coverage of the NB-IoT basestation. In this thesis, we analyse results from extensive experimental studies on the coexistence of NB-IoT and radar systems. We believe this study can be leveraged by future studies to mititage the impact of radar on IoT networks.
| Identifer | oai:union.ndltd.org:VTETD/oai:vtechworks.lib.vt.edu:10919/77960 |
| Date | 08 June 2017 |
| Creators | Vaka, Pradeep Reddy |
| Contributors | Electrical and Computer Engineering, Park, Jung-Min Jerry, Zeng, Haibo, Yang, Yaling |
| Publisher | Virginia Tech |
| Source Sets | Virginia Tech Theses and Dissertation |
| Detected Language | English |
| Type | Thesis |
| Format | ETD, application/pdf, application/pdf |
| Rights | In Copyright, http://rightsstatements.org/vocab/InC/1.0/ |
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