A master PDCH (MPDCH), is a PDCH carrying a PBCCH and PCCCH, as well as GPRS traffic. The PCCCH carries all the necessary control signaling to initiate packet traffic. In the standard, the MPDCH is called “the PDCH carrying the PBCCH”. NB the abbreviation MPDCH is only used within Ericsson systems.
The first directed PDCH that is allocated according to the operator’s preferences regarding non-hopping BCCH will be configured as an MPDCH. The following PDCHs that are allocated will only carry GPRS traffic and associated signaling. However in a cell with no MPDCH (i.e. no dedicated PDCH allocated) the ordinary control channels such as the BCCH, RACH etc, will handle the broadcasting and signaling to the GPRS mobiles.