HSC welcomes all external visitors to this site, especially students and members of the academic community. Please use the comments box at the bottom of each page to record any comments or suggestions for improvement.
Software Defined Radio(SDR) are radios that provide software control of a variety of modulation techniques, wide-band or narrow-band operation, communications security functions such as hopping, and waveform requirements of current and evolving standards over a broad frequency range.
Introduction
GNU Radio is a free software toolkit for building software radios. Software radio is a revolution in radio design. Software radio is the art and science of building radios using software. The motivation behind the software radio is is to get the software as close to the antenna as is feasible. Ultimately, we're turning hardware problems into software problem. This would give us the flexibility to create radios that change it on the fly, giving more choices to the user. Software radios can do pretty much anything a traditional radio can do. The most exciting thing about software radio is the flexibility that software provides us. Instead of a bunch of fixed function gadgets, in the next few years we'll see a move to universal communication devices.
Few things that software radios can do that haven't been possible before:
"on-the-fly" reconfiguration.
- quick and easy up-gradation of the device with
- Talk and listen on multiple channels at the same time.
- Building smart and cognitive radios.
Basic Architecture in Software Radio
This is a typical RX path for a software radio:
Antenna -> Receive RF Front End -> ADC -> Software
Code
This is a typical TX path for a software radio:
Software Code -> DAC -> Transmit RF Front End ->
Antenna
Software radio alters traditional radio designs in following distinct and complimentary manner
- Moves analog/digital (A/D) conversion as close to the receiving antenna as possible
- Substitutes software for hardware processing
- Facilitates a transition from dedicated to general-purpose hardware.
Each of these changes has important implications for the economics of wireless services.
ADC conversion closer to antenna
Moving the ADC closer to the antenna makes it possible to apply the advances of digital computing in the radio. This is beneficial directly because digital components are less complex and lower cost than analog components. Additionally, this makes it easier to take advantage of advances in digital signal processing. These include advanced techniques for encoding information and separating signal from noise.
Mostly, we can treat the RF front end as a black box with a single control, the center of the input range that's to be translated.
Software radio facilitates the use of general-purpose hardware. Initially, dedicated hardware embodied in Application Specific Integrated Circuits (ASICs) may be replaced by Field Programmable Gate Arrays (FPGAs) and Digital Signal Processors (DSPs). The requirement being that the general-purpose computing platforms (e.g., a PC running on a commodity CPU) should be able to support software radios.
Categories: Wireless
Comments
