ETSI - TS 101 376-4-12
GEO-Mobile Radio Interface Specifications (Release 3); Third Generation Satellite Packet Radio Service; Part 4: Radio interface protocol specifications; Sub-part 12: Mobile Earth Station (MES) - Base Station System (BSS) interface; Radio Link Control/Medium Access Control (RLC/MAC) protocol; GMR-1 3G 44.060
|Publication Date:||1 December 2012|
The present document specifies the procedures used at the radio interface (Reference Point Um, see TS 101 376-4-2 ) for the GMR-1 General Packet Radio Service (GMPRS-1) Medium Access Control/Radio Link Control (MAC/RLC) layer.
The present document is applicable to the following GPRS Um functional layers:
• Radio Link Control functions;
• Medium Access Control functions; and
• Physical Link Control functions.
The procedures described in the present document are for the RLC/MAC functions of the GMPRS radio interface (Um) when operating on a Packet Data Channel (PDCH).
The present document provides the overall description for RLC/MAC layer functions of the general Packet Radio Service (GMPRS) radio interface Um. TS 101 376-3-22  contains an overview of the GPRS radio interface (Um).
TS 101 376-4-3  and TS 101 376-4-4  contain the definition of the control channels used in the present document.
TS 101 376-4-7  contains a description in general terms of the structured functions and procedures of this protocol and the relationship of this protocol with other layers and entities.
TS 101 376-4-8  contains the definition of GMR-1 3G RLC/MAC procedures when operating on the Common Control Channel (CCCH).
TS 101 351  contains functional procedures for the Logical Link Control (LLC) layer.
Application to interface structure
The RLC/MAC procedures apply to the interface structures defined in TS 101 376-4-3 . They use the functions and services provided by layer 1 defined in TS 101 376-4-4 . TS 101 376-4-7  gives the general description of layer 3 including procedures, messages format and error handling.
Use of logical control channels
The logical control channels are defined in TS 101 376-5-2 . Two similar sets of logical channels are defined. The first set consists of the logical channels:
• Broadcast Control Channel (BCCH): downlink only, used to broadcast Cell specific information;
• Paging Channel (PCH): downlink only, used to send page requests to Mobile Earth Stations (MESs);
• Random Access Channel (RACH): uplink only, used to request GPRS resources or a Dedicated Control Channel;
• Access Grant Channel (AGCH): downlink only, used to allocate GPRS resources or a Dedicated Control Channel.
The second set consists of the logical channels:
• Packet Random Access Channel (PRACH): uplink only, used to request GPRS resources;
• Packet Access Grant Channel (PAGCH): downlink only, used to allocate GPRS resources;
• Packet Associated Control Channel (PACCH): bi-directional, associated with a Temporary Block Flow (TBF);
• Packet Timing advance Control Channel Uplink (PTCCH/U): used to transmit Packet Normal bursts to allow estimation of the timing advance for one MES in transfer state;
• Packet Timing advance Control Channel Downlink (PTCCH/D): used to transmit timing advance updates for several MES. One PTCCH/D is paired with several PTCCH/Us.