Digital audio radio service

Digital audio radio service (DARS) refers to any type of digital radio program service. In the United States it is the official FCC term for digital radio services.

The most popular type of DARS in the U.S. and Canada is SDARS: Satellite Digital Audio Radio Service, used by Sirius Satellite Radio and XM Satellite Radio. XM and Sirius both operate in the 2.3-GHz S band, from 2320 to 2345 MHz.

Increasing the spectrum available for more services would be difficult, since unlike C-band and K_u band services, which allow over 200 locations for satellites, S-band satellites must be spaced far apart, with current technology. Existing vehicle antennas would not allow reception of two different stations on the same frequency, though new technology, requiring a new kind of receiver, might be possible.

WorldSpace also operated a DARS network outside of the United States and Canada with a footprint covering Europe, Asia, the Middle East and Africa. It used the L-band.

...
Wikipedia