The present invention generally relates to the transmission of digital
data, and more particularly, to the transmission of digital data in a
satellite digital audio radio ("SDAR") system. In the SDAR system, there
may be different types of required services. Some of these services may
be considered high priority and others may be of a lower priority.
Current SDAR systems have the same performance on all user data.
Therefore, there is a need to vary the performance of different
services.The present invention provides a method and apparatus for
optimizing the throughput (i.e. information) in a digital transmission
system by transmitting the different services with different performance
levels. The present invention addresses the need in the art to vary the
performance of different services (i.e., levels of data). Because the
performance of the primary level of data will not be equal to the
performance of the secondary level of data, the primary level will need
to be further protected. The primary level data may be streaming data.
The secondary level data does not need as much protection because it may
be rebroadcast repeatedly. The easiest and most cost effective solution
is to integrate multiple symbols for a secondary level bit. The present
invention provides a method and apparatus in which the power level for
the data levels can be set within each data packet using a message header
providing the different services with different levels of performance.