ific broadcast information. Packet Common Control Channel (PCCCH) Packet Common Control Channel (PCCCH) is a common control channel service that is comprised of the following logical channels for common chan- nel signaling for the packet data: Downloaded from Digital Engineering Library @ McGraw-Hill (www.digitalengineeringlibrary.com) Copyright © 2004 The McGraw-Hill Companies. All rights reserved. Any use is subject to the Terms of Use as given at the website. System Architecture System Architecture 1. Packet Broadcast Control Channel Figure 3-11 The logical channels Packet RACH Packet PCH 2. Packet Common Control Channel Packet AGCH Packet NCH Packet Data TCH (Down) 3. Packed Traffic Channel Packet Data TCH (Up) PACCH Packet Timing CCH (Up) 4. Packet Dedicated Control Channel Packet Timing CCH (Down) Packet Random Access Channel (PRACH) An uplink function used by the mobile station to access the system and send control information of traffic packet data. Packet Paging Channel (PPCH) A downlink function used for paging the mobile station for mobile-terminated communications. The PPCH may be shared for packet data as well as circuit data services page the mobile station. Packet Access Grant Channel (PAGCH) A downlink function used to assign radio resources to the mobile station during call setup. Packet Notification Channel (PNCH) A downlink function used to send a notification of the point-to-multipoint multicast to a group of mobile stations prior to sending the data. The point-to-multipoint service is not specified in Phase I of GPRS, but was addressed as part of Phase II. Packet Data Traffic Channel (PDTCH) The traffic channel is an up and downlink function used for user data traf- fic transfer. The PDTCH is temporarily dedicated to a user or group of users (for multipoint). PDTCH for uplink and PDTCH for downlink are unidirec- tional and assigned separately to support asymmetric user traffic flow. Downloaded from Digital Engineering Library @ McGraw-Hill (www.digitalengineeringlibrary.com) Copyright © 2004 