Assessing Directional Time-Dependent Interference Vulnerabilities in Closed-Box Wireless Systems

Abstract

A general-purpose methodology to assess time-dependent interference vulnerabilities is demonstrated with two different consumer off-the-shelf (COTS), closed-box wireless systems at both the source (data payload origin) and destination (data payload recipient). Specifically, using a point-to-point microwave link operating in the unlicensed U-NII-5 6 GHz band and an IEEE 802.11n Wi-Fi link operating in the U-NII-1 5 GHz band, we evaluate the impact of injected pulse-modulated noise (PMN) with various signal periods at both the source and destination. Observed distributions of link throughput demonstrate 1) asymmetric variations in link response depending on whether interference targeted the source or destination 2) throughput degradations on some interference time-scales that are problematic for critical applications requiring a consistent quality of service 3) intersystem differences in susceptibility to particular time-scales. Furthermore, compared to stationary additive white Gaussian noise (AWGN) with the same average power, impacts from PMN are observed to induce greater link degradation at both the source and destination, emphasizing the need to reexamine established test methods that use stationary AWGN as a preferred interference benchmark.