Forward Traffic Code Channel


Forward Traffic Code Channel
Forward Traffic Code Channels
The forward traffic code channels are used to transmit user data and signaling information.  The Forward Traffic Code Channels are separated by their unique Walsh code assignments. Once the mobile is assigned a Walsh code in an omni cell (or sector), the code cannot be assigned to any other mobile in that omni cell (or sector) for the entire duration of the call.   A Forward Traffic Channel can be comprised of a Fundamental Code Channel and Supplemental Code Channels.
The Fundamental Code Channel
The Fundamental Forward Code Channel is used to transmit user data, signaling, and the power control sub-channel.
The Supplemental Code Channel
Supplemental Code Channels may be used to provide the subscriber with a high speed data capability.  The bit rate of a single Fundamental Code Channel is limited by the Rate Set frame formats.  A Forward Traffic Channel may include several Supplemental Channels to provide the required bit rate.  Each Supplemental Code Channel requires an additional unique Walsh Code assignment.  The Supplemental Code Channels always transmit at the maximum rate for the rate set in use and do not carry any signaling or power control sub-channel information.  Supplemental Code Channels are a TIA/EIA-95 capability and are not defined in IS-95A.