Terrestrial Transmission of Digital Television Signals (DVB-T) - Digital Video and Audio Broadcasting Technology - page 377

can be addressed. Like a table, the content of the MIP packet is protected
by a CRC checksum.
In addition, each transmitter can also be “pushed”, i.e. it is possible to
change the time when the COFDM symbol is broadcast. This will not push
the single frequency network out of synchronization but only vary the de-
lay of the signals of the transmitters with respect to each other and can thus
be used for optimizing the SFN network. These time offsets are found in
the 'TX time offset' functions in Fig. 20.27. Shifting the broadcasting time
makes it appear to the receiver as if the geographic position of the respec-
tive transmitter has changed. This may be of interest if two transmitter in
an SFN are very far apart and are approaching the limit of the guard inter-
val (e.g. DVB-T network Southern Bavaria with the Olympic tower in
Munich and the Mount Wendelstein transmitter at a distance d of 63 km)
or if the guard interval has been chosen to be very short for reasons of data
rates (e.g. Sydney, Australia, with g=1/16).
Fig. 20.27. MIP packet analysis [DVMD]