Chapter 1 – When radio meets software

Data communication networks are a vital component of any modern society. They are used extensively in numerous applications, including financial transactions, social interactions, education, national security, and commerce. In particular, both wired and wireless devices are capable of performing a plethora of advanced functions that support a range of services, such as voice telephony, web browsing, streaming multimedia, and data transfer. With the rapid evolution of microelectronics, wireless transceivers are becoming more versatile, powerful, and portable. This has enabled the development of software-defined radio (SDR) technology, where the radio transceivers perform the baseband processing entirely in software: modulation/demodulation, error correction coding, and compression. Since its introduction in 1991, SDR has been defined as a radio platform of which the functionality is at least partially controlled or implemented in software. Consequently, any waveform defined in the memory of the SDR platform can be employed on any frequency [1]. Although initially constrained by the conversion process between the analog and digital signaling domains, the emergence of cheap highspeed digital-to-analog converters (DACs) and analog-to-digital converters (ADCs) has brought the ideal SDR concept of an entirely software communication system implementation (including radio frequency functionality) closer to a reality. Wireless devices that can be described as SDR have in fact been around for several decades. They were initially employed in military applications before finding applications in the commercial sector. Military programs such as SPEAKeasy sought to enable communication and interoperability between several military standards [2]. Although ambitious, the SPEAKeasy project did produce a functional prototype, even though the design choices involved in programming waveforms using low-level assembly language meant that the software was not compatible