After each access attempt, the mobile listens to the Paging Channel for a response from the base station. If the base station detects the access probe from the mobile, it responds with a channel assignment message.
This message contains all of the information required to get the mobile onto a traffic channel. this messages includes such information as the Walsh code channel to be used for the forward traffic channel, the frequency being used, and the frame offset to indicate the delay between the forward and reverse links.
Once the mobile has acknowledge the channel assignment message, the base station initiates the land link and the mobile moves from the access channel to the traffic channel. At this point, a conversation can take place.
Any further signaling required once the traffic channel is established takes place on the traffic channel. To accommodate signaling, EIA/TIA-95-B supports two methods of temporarily grabbing the traffic channel: blank and burst signaling, and dim and burst signaling.
Both are similar with the difference that the blank and burst steals a contiguous block of frames to transmit signaling messages, while dim and burst reduces the vocoder rate and then uses the remaining traffic channel time to more slowly send signaling messages.
- Base Answers Access Probe using the Channel Assignment Message
- Mobile Goes to A Traffic Channel Based on the Channel Assignment Message Information
- Base Station Begins to Transmit and Receive Traffic Channel