control the enhanced features or provide additional content as will be described in more detail below mapping can be static or dynamic a static based implementation supplies the service content to a receiver on a predetermined periodicity or multiple thereof whereas a dynamically based implementation supplies the service content for different services by signaling to the receiving device that the information is deterministically changing fig7 depicts several possible service modes including mobile 710 indoor 708 handheld 706 and fixed 712 services receiving data from a single frequency network providing enhancements in accordance with the present invention the present invention can be used across one or more of the exemplary services shown the present invention also uses transmitter diversity to provide coherent signals from different locations such as transmitter 702 single frequency network transmission system 704 and a smaller building transmitter 714 frequency synchronization of the pilot or carrier is achieved by locking the carrier frequency of an exciter in the rf transmitter system to a reference from a gps timebase transmitter diversity allows transmitters at different locations to transmit coherent symbols the start of a data frame is determined i e synchronized by identifying a point in the transport stream via a special timing packet generally a transport stream ts having a specialized.