sOFtware-defined radios (SDRs) have been around for more than a decade. The
first complete Global Positioning System (GPS) implementation was described
by Dennis Akos in 1997. Since then several research groups have presented their
contributions.We therefore find it timely to publish an up-to-date text on the subject
and at the same time include Galileo, the forthcoming European satellitebased
navigation system. Both GPS and Galileo belong to the category of Global
Navigation Satellite Systems (GNSS).
sOFtware-defined radios (SDRs) have been around for more than a decade. The
first complete Global Positioning System (GPS) implementation was described
by Dennis Akos in 1997. Since then several research groups have presented their
contributions.We therefore find it timely to publish an up-to-date text on the subject
and at the same time include Galileo, the forthcoming European satellitebased
navigation system. Both GPS and Galileo belong to the category of Global
Navigation Satellite Systems (GNSS)
The first question most readers of an O’Reilly book might ask is about the choice of the
cover animal. In this case, “why a duck?” Well, for the record, our first choice was a
unicorn decked out in glitter and a rainbow sash.
That response always gets a laugh (we are sure you just giggled a little), but it also brings
to the surface a common perception of sOFtware-defined networks among many expe‐
rienced network professionals. Although we think there is some truth to this perception,
there is certainly more meat than myth to this unicorn.
Until the mid-1990s most readers would probably not have even come across the term soft-
ware defined radio (SDR), let alone had an idea what it referred to. Since then SDR has made
the transition from obscurity to mainstream, albeit still with many different understandings of
the terms – software radio, software defined radio, software based radio, reconfigurable radio.
