6.10 Example of PBCCH + PCCCH Configuration

The multiplexing of the packet channels on a PDCH is not fixed like in the GSM system. In GPRS, it is managed by some parameters and the following block order: B0, B6, B3, B9, B1, B7, B4, B10, B2, B8, B5, and B11.

Figure 6-10 shows the parameters that manage the multiplexing of the packet channels on the same PDCH:

Figure 6-10: An example of the packet logical channel configuration.

• BS_PBCCH_BLKS This indicates the number of PBCCH blocks used to broadcast the PSI.

  These blocks are always the first blocks according to the multiframe blocks order. The parameter is broadcast on the first PBCCH block (B0). If many PCCCH channels (the total number of PCCCH channels is given by the parameter BS_PCC_CHANS broadcast on PBCCH) are present, PDTCH may be transmitted at the PBCCH blocks position in the other PCCCH channels (because PBCCH blocks are only transmitted on one single time slot in the cell).

• BS_PAG_BLKS_RES (number of blocks for access grant) Indicates the number of PCCCH blocks following the PBCCH blocks (according to the multiframe blocks order) on which paging is forbidden.

  These blocks are thus reserved for PAGCH, and eventually PDTCH/PACCH/PTCCH. If one of these blocks is used for PAGCH, then the corresponding UL channels can be used for network access (PRACH), so uplink state flag (USF) is annotated as being free in the MAC header of the radio block. If one of these blocks is used for...