Biblio
The wireless spectrum is a scarce resource, and the number of wireless terminals is constantly growing. One way to mitigate this strong constraint for wireless traffic is the use of dynamic mechanisms to utilize the spectrum, such as cognitive and software-defined radios. This is especially important for the upcoming wireless sensor and actuator networks in aircraft, where real-time guarantees play an important role in the network. Future wireless networks in aircraft need to be scalable, cater to the specific requirements of avionics (e.g., standardization and certification), and provide interoperability with existing technologies. In this paper, we demonstrate that dynamic network reconfigurability is a solution to the aforementioned challenges. We supplement this claim by surveying several flexible approaches in the context of wireless sensor and actuator networks in aircraft. More specifically, we examine the concept of dynamic resource management, accomplished through more flexible transceiver hardware and by employing dedicated spectrum agents. Subsequently, we evaluate the advantages of cross-layer network architectures which overcome the fixed layering of current network stacks in an effort to provide quality of service for event-based and time-triggered traffic. Lastly, the challenges related to implementation of the aforementioned mechanisms in wireless sensor and actuator networks in aircraft are elaborated, and key requirements to future research are summarized.
The exponential growth in the number of mobile devices, combined with the rapid demand for wireless services, has steadily stressed the wireless spectrum, calling for new techniques to improve spectrum utilization. A geo-location database has been proposed as a viable solution for wireless users to determine spectrum availability in cognitive radio networks. The protocol used by secondary users (SU) to request spectral availability for a specific location, time and duration, may reveal confidential information about these users. In this paper, we focus on SUs' location privacy in database-enabled wireless networks and propose a framework to address this threat. The basic tenet of the framework is obfuscation, whereby channel requests for valid locations are interwoven with requests for fake locations. Traffic redirection is also used to deliberately confuse potential query monitors from inferring users' location information. Within this framework, we propose two privacy-preserving schemes. The Master Device Enabled Location Privacy Preserving scheme utilizes trusted master devices to prevent leaking information of SUs' locations to attackers. The Crowd Sourced Location Privacy Preserving scheme builds a guided tour of randomly selected volunteers to deliver users channel availability queries and ensure location privacy. Security analysis and computational and communication overhead of these schemes are discussed.