Adding transmission diversity to unmanned systems through radio switching and directivity
Christopher J. Lowrance, Adrian P. Lauf · 2014
Wireless communication is an essential component of many unmanned systems, yet presently, there are some communication challenges that limit the full potential of these systems. In particular, transmission distance, throughput efficiency using Transmission Control Protocol (TCP), and wireless spectrum availability are a few of these challenges. In order to mitigate these specific problems, we propose an autonomous radio switching algorithm that allows unmanned systems to autonomously select the optimum radio between a set of diverse options, given the current conditions. More specifically, this study considers diversity between radios using the same common protocol but equipped with different antennas. A fuzzy logic controller is utilized to intelligently select whether to employ a directional or omnidirectional antenna based on the operating conditions at transmission time. Directional antennas offer many advantages, but are not ideal under all circumstances, and with the typical power constraints of unmanned systems, it is more costly in terms of current consumption to operate multiple radios simultaneously. Therefore, if only one radio is needed at a time, it is more energy efficient to implement smart radio switching. To autonomously facilitate this switching operation, we present a fuzzy controller called, “Autonomous Radio Switching for Unmanned Systems (ARSUS)” and show its effectiveness in improving TCP throughput and increasing transmission range.