Flight Test and Validation of Variable Coded Modulation Using SCaN Testbed

— This article reports on the development and validation of variable coded modulation (VCM) on the Jet Propulsion Laboratory (JPL) software-defined radio (SDR). Flight tests were conducted to evaluate performance of the VCM waveform over an S-band link between the Space Communications and Navigation (SCaN) Testbed and the Glenn Research Center (GRC). The tests verified the VCM waveform’s ability to switch to different modulation and coding modes adapting to varying link conditions, and demonstrated improvement in effective data throughput as compared to NASA standard waveforms. We also describe a suite of ground receiver tools that were developed to autonomously acquire, track, and post-process the JPL VCM waveform. Processing results from one of the tests indicate an overall improvement of ∼ 2 dB in data throughput over standard waveforms. The demonstrated technologies are building blocks of a future cognitive radio system with the capability to adapt its operation to the communication environment in near real time.