 station radio capability (2 + 1 or 3 + 1, and SO on), the number of octets for user data (RLC octet count), the LLC-PDU type, the Temporary Logical Link Identity (TLLI), and the RLC mode (acknowledged or unacknowledged). Resource Assignment The network will respond by sending Radio Resource Assignment messages on one or more PDCHs to be used by the mobile station for the Temporary Block Flow (TBF) in a Packet Uplink Assignment message on PACCH. This message contains the absolute radio frequency channel number (ARFCN) parameter, one or several time slots, TBF starting time, Temporary Block Flow Identifier (TBFI), TA, channel coding scheme (CS1, CS2, CS3, CS4), TLLI for contention resolution, and If using static allocation, it contains bitmap allocation and downlink control time slot. If using dynamic allocation, it contains USF. For each TBF (UL or DL), the PCU assigns specific blocks on one or sev- eral time slots, allocated for the TBF. These blocks are described in a bitmap that is transmitted to the mobile station or not transmitted according to the case (UL or DL packet transfer, static or dynamic UL resource allocation, and so on). In GPRS, a single mobile station can be assigned up to eight PDCHs for one packet transfer or up to eight mobile stations may simulta- neously share the same PDCH. When several mobile stations share the same PDCH, the multiplexing of these mobile stations is managed by the PCU through a bitmap indicat- ing which mobile station should use each block. The uplink and downlink may have different bitmaps in GPRS, because the GPRS channels are asymmetric and independent. However, the bitmaps of the mobile stations sharing the same way as on the same PDCH are disjointed (similar to the Radio Site Masks of several BTSs sharing the same Pulse Coded Modula- tion [PCM] links on the Abis interface) in order to avoid collisions. Downloaded from Digital Engineering Library @ McGraw-Hill (www.digitalengineeringlibrary.com) Copyright © 2004 The McGraw-Hill Companies. All rights reserved. Any use