This downlink channel is used for the broadcast of system information. It maps the Broadcast Channel (BCH) or Forward Access Channel (FACH) to a Transparent Mode (TM) RLC entity.
The Broadcast Channel (BCH) is a transport channel that is used to transmit information
specific to the UTRA network or for a given cell.
The most typical data needed in every network is the available random access codes and access slots in the cell, or the types of transmit diversity method used with other channels for that cell.
As the terminal cannot register to the cell without the possibility of decoding the broadcast channel, this channel is needed for transmission with relatively high power in order to reach all the users within the intended coverage area.
From a practical viewpoint, the information rate on the broadcast channel is limited by the ability of low-end terminals to decode the data rate of the broadcast channel, resulting in a low and fixed data rate for the UTRA broadcast channel.
