Marina, Mahesh

Sarkar, Rik

Rathinakumar, Saravana Manickam

2018-07-06T13:59:47Z

2018-07-06T13:59:47Z

2018-07-02

Wireless spectrum is a limited resource that must be used efficiently. It is also a broadcast medium, hence, additional procedures are required to maintain communication over the wireless spectrum private. In this thesis, we investigate three key issues related to efficient use and privacy of wireless spectrum use. First, we propose GAVEL, a truthful short-term auction mechanism that enables efficient use of the wireless spectrum through the licensed shared access model. Second, we propose CPRecycle, an improved Orthogonal Frequency Division Multiplexing (OFDM) receiver that retrieves useful information from the cyclic prefix for interference mitigation thus improving spectral efficiency. Third and finally, we propose WiFi Glass, an attack vector on home WiFi networks to infer private information about home occupants. First we consider, spectrum auctions. Existing short-term spectrum auctions do not satisfy all the features required for a heterogeneous spectrum market. We discover that this is due to the underlying auction format, the sealed bid auction. We propose GAVEL, a truthful auction mechanism, that is based on the ascending bid auction format, that avoids the pitfalls of existing auction mechanisms that are based on the sealed bid auction format. Using extensive simulations we observe that GAVEL can achieve better performance than existing mechanisms. Second, we study the use of cyclic prefix in Orthogonal Frequency Division Multiplexing. The cyclic prefix does contain useful information in the presence of interference. We discover that while the signal of interest is redundant in the cyclic prefix, the interference component varies significantly. We use this insight to design CPRecycle, an improved OFDM receiver that is capable of using the information in the cyclic prefix to mitigate various types of interference. It improves spectral efficiency by decoding packets in the presence of interference. CPRecycle require changes to the OFDM receiver and can be deployed in most networks today. Finally, home WiFi networks are considered private when encryption is enabled using WPA2. However, experiments conducted in real homes, show that the wireless activity on the home network can be used to infer occupancy and activity states such as sleeping and watching television. With this insight, we propose WiFi Glass, an attack vector that can be used to infer occupancy and activity states (limited to three activity classes), using only the passively sniffed WiFi signal from the home environment. Evaluation with real data shows that in most of the cases, only about 15 minutes of sniffed WiFi signal is required to infer private information, highlighting the need for countermeasures.

http://hdl.handle.net/1842/31294

en

The University of Edinburgh

Saravana Rathinakumar., Bozidar Radunovic., & Mahesh K. Marina. (2016). CPRecycle: Recycling Cyclic Prefix for Versatile Interference Mitigation in OFDM based Wireless Systems. In Proceedings ACM CoNEXT 2016.

Saravana Rathinakumar., & Mahesh K. Marina. (2016). GAVEL: strategy-proof ascending bid auction for dynamic licensed shared access. In Proceedings ACM Mobi- Hoc 2016.

Saravana Rathinakumar., Bozidar Radunovic.,&Mahesh K.Marina. (2015). ShiftFFT: An efficient approach to mitigate adjacent channel interference in OFDM systems. In proceedings of HotWireless workshop at ACM Mobicom 2015.

Saravana Rathinakumar., Mahesh K. Marina., Sofia Pediaditaki., & Maziar Nekovee. (2014). An iterative and truthful multiunit auction scheme for coordinated sharing of spectrum white spaces. In Proceedings of NetEcon Workshop at ACM Sigmetrics 2014.

wireless spectrum

efficient use

privacy

GAVEL

short-term auction mechanism

CPRecycle

OFDM receiver

WiFi Glass

attack vector

spectrum auctions

encryption

Research on efficiency and privacy issues in wireless communication

Thesis or Dissertation

Doctoral

PhD Doctor of Philosophy