An approachable guide to an invaluable radio frequency communication toolkit Software-defined radio (SDR), which emerged in the 1990s, has become a core development method in certain high-profile fields, including military and space communications. High cost and problems with hardware availability, however, prevented this technology from being widely disseminated. The advent of low-cost hardware beginning in the 2010s, however, has made GNU Radio—the leading open-source software toolkit for developing SDR systems—an increasingly viable and even critical tool for a new generation of radio frequency communication engineers. Communication Systems Engineering with GNU Radio provides an accessible overview of this toolkit and its applications. Beginning with the fundamentals of using GNU radio for digital signal processing, the volume then moves to the practicalities of decoding data and the advantages of accessing raw data normally unavailable in hardware-defined radio frequency