In Europe, digital radio is also to be transmitted as satellite radio (S-DAB). Two systems compete in the U.S.: XM Satellite Radio and Sirius Satellite Radio. Although XM radio can also be received in Europe via the WorldSpace satellite, it has nowhere near the acceptance as Digital AudioBroadcast (DAB).
XM radio, popular in the US, is a pay satellite radio, broadcast from three GEO satellites in the 2.3 GHzfrequency range. XM-Radio uses terrestrialrepeaters in densely populated areas, improving indoor reception and allowing regional programming to be fed in.
XM-Radio broadcasts about 150 radio channels, many of which are music channels, others sports, weather, traffic, news or other special interest channels. The broadcasts can be received by stationary receiving equipment, but also by mobile ones in motor vehicles. The high audio quality is achieved through appropriate audio compression - aacPlus is used.voice, XM radio also transmits program-accompanying data ( PAD) in which the channel, the piece of music, the artist and other data are transmitted. Furthermore, XM-Radio is also broadcast as internet radio after a cooperation with America Online (AOL).