A software-defined radio (SDR) is one that has the capability – through use of programmable hardware (handsets) controlled by software - to tune to any frequency band and receive any modulation across a large frequency spectrum.
At present, certain radio frequencies have to be reserved for particular functions e.g. the emergency services. But the proliferation of such reserved frequencies is beginning to crowd out the airwaves i.e. to create a shortage of bandwidth. SDR, however, should be able to overcome these problems through being able to achieve what is referred to as ‘cognitive spectrum management’, whereby it would be able to identify spare bandwidth flexibly on a case-by-case basis. This sharing of the spectrum that SDR allows is a very important capability...