Shared Spectrum Company (United States)

In recent years, the use of Unmanned Aircraft Systems (UAS), also known as drones, has been on the rise covering several areas that span from surveillance to retail delivery of goods. This proliferation can be accredited to various advances such as low-latency connectivity, fast execution of control commands, high reliability and more importantly their potential for autonomous operations. Consequently, this allowed the information fusion community to develop various methods of fusion of different types of data. However, these methods in general do not thoroughly consider the proliferation of cyber attacks targeting UAS vehicles especially for civilian and military missions. In this paper, we propose a novel approach leveraging information fusion to secure autonomous drone operations entitled Information Fusion for Secure Drone Operations (IFSDO). Our solution allows the distribution and enforcement of security policies and dynamic spectrum allocation policies to drones during all mission phases depending on the user role. IFSDO works by orchestrating different techniques including cryptography, attribute-based access control and ontological rules to allow the drone to autonomously and securely manage various types of access requests to ensure the mission can be conducted safely. We validate our findings with a case study illustrating the initial exchange of critical data between the security manager and the drone as part of a civilian package delivery mission involving several stakeholders interacting with the drones. The initial results show promising potential of success of our approach.

Spectrum sharing between Department of Defense (DoD) airborne Tactical Data Links (TDL) and commercial Electronic News Gathering (ENG) systems in the 2025-2110 MHz band poses distinct challenges due to the nature of DoD TDL and ENG systems. The TDL’shigh transmit power, high-speed mobility, and potential direct air-to-ground line of sight to ENG systems makes it the most difficult system for spectrum coexistence. This paper presents a hybrid spectrum sharing approach that combines geographic exclusion zones, adding a beacon signal to the ENG system, and incorporating sensing in the TDL system. The hybrid approach maximizes spectrum access while minimizing interference risks and operational costs. The proposed hybrid approach is also applicable to the other DoD systems in the $2025-2110 \mathrm{MHz}$ band, which includes tactical radio relay (TRR), small unmanned aircraft systems (SUAS), and high-resolution video (HRV). The paper describes the hybrid system approach, outlines the technical and operational requirements, provides performance estimates, and assesses characteristics of the hybrid approach relative to alternative approaches.

This paper describes field experiments of an 802.16-based radio that has an innovative cognitive radio technology that significantly increases the link range, increases battery life, or reduces a radios' RF signature. The SAFE (Smart Access Frequency Exploitation) radio combines Dynamic Spectrum Access (DSA) and channel sounding capabilities simultaneously. This enables spectrum sharing on a noninterference basis with other users and selects the radios' operating frequency that has minimal link (antenna and propagation) loss, and uses a transmit power control algorithm to reduce the transmit power level. There are multiple frequency dependent factors that determine link loss (multi-path, reflection coefficients, antenna gain, power amplifier gain, foliage/wall penetration, atmospheric refraction, etc.). SAFE exploits these propagation factors, and provides 10-20 dB less link loss compared to a conventional, fixed tuned radio. This provides a significant improvement in link range, increased battery life or a reduction in the radio's signature. The SAFE radios were separated by a long (non-line of sight) distance in an outdoor, hilly area. The link distance, the obstacles, and the radio transmit power are selected so that the radios was near its maximum range. The link range distances (1 km to 4.5 km) were found empirically based on the terrain blockage. The field tests validate the 10-20 dB link loss reduction.

Many Internet failures are caused by misconfigurations of the BGP routers that manage routing of traffic between domains. The problems are usually due to a combination of human errors and the lack of a high-level language for specifying routing policies that can be used to generate router configurations. We describe an implemented approach that uses a declarative language for specifying network-wide routing policies to automatically configure routers and show how it can also be used by software agents to diagnose and correct some networking problems. The language is grounded in an ontology defined in OWL and polices expressed in it are automatically compiled into low-level router configurations. A distributed collection of software agents use the high-level policies and a custom argumentation protocol to share and reason over information about routing failures, diagnose probable causes, and correct them by reconfiguring routers and/or recommending actions to human operators. We have evaluated the framework in both a simulator and on a small physical network. Our results show that the framework performs well in identifying failure causes and automatically correcting them by reconfiguring routers when permitted by the policies.

The purpose of this study is to determine a range of detection thresholds at which new dynamic spectrum access (DSA) devices can safely operate in unoccupied spectrum allocated to terrestrial television (TV) broadcasting and other services (i.e., the TV "white spaces"), without causing harmful interference to other authorized operations, which include digital and analog TV stations, wireless microphones and other services. Spectrum sensing data were collected at six different locations in Northern Virginia that were strategically chosen because they were within, outside and near the edges of the predicted service contours of digital TV stations serving the Washington, D.C. and Baltimore, MD metropolitan areas. We used a pair of DSA devices that jointly decide if a channel can be used or not. This emulates how SSC's and other DSA devices operate. The joint decision logic mitigates the propagation shadowing and hidden node problem. The separation between the DSA devices was less than approximately 10 km, which corresponds to the link range of a 10 W 802.16-based transmitter. The DSA detectors used a high sensitivity detector that is able to detect the ATSC pilot down to a -140 dBm level (ATSC signal power level of -128 dBm). The detector is not noise limited. "False alarms" are caused by detection of distant TV transmitters when the DSA system is located outside the Grade B contour. Based on analysis results from data recorded from six independent locations in Northern Virginia and 13 ATSC channels.

This paper investigates the performance of FFT- type feature TV detector of weak signals, which can be used in listen-before-talk (LBT) spectrum access algorithms. Using FFT plots applied to consecutive sets of measurements collected at multiple locations, we illustrate and characterize different types of spurious signal environments. Ultra sensitive TV detectors can significantly improve the overall system performance in terms of available TV channels versus transmit power. We show the system performance curves based on real measurements collected at multiple locations