measurement reports on surrounding cells to the network. MS performs autonomous cell MS continues its normal reselection. cell reselection. The MS sends measurement reports on surrounding cells Network control to the network MS performs no cell reselection on its own. Cell reselection command How the Mobile Knows the PDCH Configuration The mobile station has to decode some parameters broadcast by the net- work, in order to know the packet channel multiframing and how to access the network. The following list examines the decoding scheme, which is also shown in Figure 6-9: PBCCH description The mobile station first decodes the BCCH channel of the initially selected cell. One BCCH is always transmitted on SI 13 (if the cell supports the GPRS service), which indicates all the GPRS relevant parameters, among others, if specific Packet Common Control Channels are used in the cell for GPRS (PBCCH, PRACH, PAGCH, and PPCH). If that is the case, a PCCCH description is sent on SI 13 (on BCCH), indicating that the PDCH is carrying PBCCH. Otherwise, if no PCCCH description is sent on SI 13, all the necessary GPRS information is transmitted on BCCH SI 13 and the mobile station decodes the BCCH of the neighboring cells for the cell reselection process. If PBCCH is used, it carries all the necessary 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. Radio and MS-PCUSN Interfaces Chapter 6 Figure 6-9 1. SI 13 decoding on BCCH: PBCCH The mobile station description learns by decoding the information. 2. B0 decoding on PBCCH: BS_PBCCH_BLKS PCUSN Network 3. PBCCH decoding: BS_PCC_CHANS+PCCCH description BS_PAG_BLKS_RES BS_PRACH_BLKS (optional) information about the neighboring cells for the cell reselection process, and the mobile station only has to perform level measurements on the neighboring cells declared in the GPRS_BA_list (sent on BCCH or on PBCCH if it ex