Are SDRs the Wave of the Future?

Joe St Sauver
joe@oregon.uoregon.edu

We're all familiar with a variety of different kinds of radios--AM/FM broadcast radios, CB radio, amateur ("ham") radio, police/fire/ambulance band radios, and so on. Each of those radios has closely defined parameters governing such factors as available frequencies, allowable power, and required spectral purity.

More recently, however, industry and the federal government (especially military and national security-related agencies) have begun to aggressively develop a new, more agile type of radio known as a "software-defined radio," or SDR.

To understand the potential of SDRs, ask yourself if it makes sense to apply invariant parameters to radio equipment that may operate in vastly different conditions. For example, consider a radio that's being used in New York City, and compare it to a radio being used in a Nevada desert. Obviously, these different locations may have different requirements (i.e., in the absence of congestion or competition for resources, using more power or appropriating unused frequencies might be feasible).

In addition, spectrum-aware software radios have superior potential to survive in hostile environments where intentional or unintentional interference might otherwise block communication.

In the past, radios have not been smart enough to sense the conditions in which they are operating and adapt accordingly. But now that a new class of smart, software-defined radios is on the horizon, increased congestion in radio frequencies and growing pressure to deploy and interconnect a host of new wireless network devices may thrust SDRs to the forefront. While you may not see SDRs widely deployed this year, it's certain they'll be out in force not too many years down the line.

For more information about software defined radios, you may want to see:

FCC Notice of Inquiry Regarding Software-Defined Radios: http://www.ntia.doc.gov/ntiahome/fccfilings/2000/sdrnoi61600.htm

How Software Defined Radios Change The Rules: http://www.dandin.com/pdf/Dandin_Chronicles_2.4.pdf

New Directions in Delivering Broadband Wireless Connectivity:
http://www.ncne.nlanr.net/training/techs/2001/0128/presentations/200101-hendricks1_files/v3_document.htm

SDR: Big Hopes for New Tech http://www.radioscape.com/Version_1_9/CMS.asp?cId=275

SDR Forum: http://www.sdrforum.org/

Software-Defined Radios and the Indefinite Future: http://www.americasnetwork.com/issues/2000issues/20001201/20001201_shapechanger.htm