ZTE Corporation ZXG-BTS2 Manuale Utente

 
ZXG10-BTS (V2.9) Technical Manual 

Confidential and Proprietary Information of ZTE CORPORATION  

M A C  H eader

RLC

Hdr

RLC  Data

s pare

M A C  H eader

RLC /M A C  Bloc k

RLC /M A C  C ontrol Bloc k

RLC /M A C  Signalling information

RLC  Data Bloc k

RLC /M A C  Bloc k

 

 

A block is carried by four NBs composed of the MAC header, RLC data 

block or RLC/MAC control block. 

The MAC header contains different control fields for uplink and downlink 

directions and has a fixed length of 8 bits. The RLC header contains 
different control fields for uplink and downlink directions but has an 

indefinite length. The RLC data block contains the data from the upper 
layer, and the RLC/MAC control block contains an RLC/MAC control 

message. 

LapD Protocol 

LapD (link access procedure of “D” channel) is a data link procedure for 
signaling transmission between BTS(V2.9) and BSC, with the purpose of 

using the D channel to transmit messages between respective Layer-3 
entities. 

LapD is a point-to-multipoint communication protocol that employs the 
frame structure. 

In ZXG10-BTS(V2.9), LapD implements the following functions:  

1.  Providing one or multiple data connections in the D channel 

The data link connections are identified by the DLCIs in the respective 

frames. DLCI consists of the TEI (Terminal Equipment Identifier) and 
SAPI (Service Access Point Identifier), indicating the service and entity 

that are accessed. 

2.  Delimitation, location and transparency of the frame 
3.  Sequence control, ensuring sequential transmission of the frames 
4. Error detection 
5.  Error recovering  
6.  Notifying the management entity of the un-recoverable error