Software Defined Radio

Software-defined radio (SDR) is a radio communication system where components that have traditionally been implemented in hardware (e.g. mixers, filters, amplifiers, modulators/demodulators, detectors, etc.) are instead performed by means of software on a general-purpose processor. A common approach is to implement the baseband processing in software and to use one or more field-programmable gate arrays (FPGAs) for an interface between the baseband processor and the antenna. This configuration allows easy modification of the radio’s behavior by reprogramming the FPGA(s) or loading new software into the baseband processor.

The concept of SDR was first proposed in 1987. The term “software radio” was coined in 1993 by Tony Fish at a Wireless World Research Forumcollaborative project meeting and has been used extensively since then.[citation needed] In 2000, Joe Mitola III defined software radios as “radio systems where functional blocks are primarily connected together using high-level programming languages”. However, with advances in digital signal processing technology it became possible to perform many of these operations in cheaper generic processors and so SDR evolved to mean radios whose architecture is defined by software rather than hardware. Software radios have significant advantages over traditional fixed-function devices; these include flexibility, due to reconfigurability; upgradability; easier development and test; better maintainability; lower production costs because fewer different types of hardware are required; reduced size, weight and power consumption (SWaP); platform independence from a particular type of Integrated circuit (IC), which can simplify design for multiple standards or multiple frequency bands. They also suffer from some limitations compared to traditional hardware implementations such as poorer performance under extreme conditions (such as strong interference),:14 greater susceptibility to malicious attack,:24:22–23and increased system complexity.:ix:15 One way around some of these problems uses heterogeneous multiprocessing,-which employs both dedicated DSP chips as well as general purpose processors interconnected using fast buses such as PCI Express.