Abstract Wireless communication devices must be protected from malicious threats, including active jamming attacks, due to the widespread use of wireless systems throughout our every‐day lives. Jamming mitigation techniques are predominately evaluated through simulation or with hardware for very specific jamming conditions. In this paper, an experimental software defined radio‐based RF jamming mitigation platform which performs online jammer classification and leverages reconfigurable beam‐steering antennas at the physical layer is introduced. A ray‐tracing emulation system is presented and validated to enable hardware‐in‐the‐loop jamming experiments of complex outdoor and mobile site‐specific scenarios. Random forests classifiers are trained based on over‐the‐air collected data and integrated into the platform. The mitigation system is evaluated for both over‐the‐air and ray‐tracing emulated environments. The experimental results highlight the benefit of using the jamming mitigation system in the presence of active jamming attacks.

Traditional approaches to experimental characterization of wireless communication systems typically involves highly specialized and small-scale experiments to examine narrow aspects of each of these applications. We present the Drexel Grid SDR Testbed, a unified experimental framework to rapidly prototype and evaluate these diverse systems using: (i) field measurements to evaluate real time transceiver and channel-specific effects and (ii) network emulation to evaluate systems at a large scale with controllable and repeatable channels. We present the hardware and software architecture for our testbed, and describe how it is being used for research and education. Specifically, we show experimental network layer metrics in different application domains, and discuss future opportunities using this unique experimental capability.

OFDM-based communication systems for Unmanned Aerial Vehicles (UAV) are designed predominately for high mobility scenarios with direct line of sight. The number of sub-channels used is selected to be small to mitigate the effects of inter-carrier interference (ICI) resulting from carrier frequency offset. We investigate interference effects in urban environments for quad-copter UAVs based on both ICI and inter-symbol interference (ISI), which results from multi-path scenarios. We propose that changing the number of sub-carriers used in the Air-to-Ground link improves bit error rate performance dependent upon the channel characteristics. In the presence of closely spaced buildings, a greater amount of multi-path will occur, motivating the use of more sub-carriers. A practical joint synchronizer is discussed to enable scalability of the proposed idea and characterize the source of ICI. Through the use of ray tracing models and realistic end-to-end simulations, we determine that UAV communications in urban environments benefit from adaptive sub-carrier counts to combat interference effects.

This paper develops an FPGA implementation of a trained coarse Carrier Frequency Offset estimation and correction scheme using MATLAB System Generator. The designed system is capable of supporting variable FFT sizes for Orthogonal Frequency Division Multiplexing signals and different pilot symbol structures making it compatible with a large number of wireless communication standards, unlike other work that is protocol specific. This design stands out from its more common implementations as it requires only one pilot symbol to be considered for synchronization by using a data-aided modified correlation scheme, allowing for an increase in throughput. The Bit Error Rate of the corrected signal received over an Additive White Gaussian Noise channel is compared to the case without correction. This scheme demonstrated increased performance throughput since only a single pilot symbol was used.