User Manual
Airbridge cBTS3612 CDMA Base Station
System Description
1 System Overview
1-11
with the network and to enjoy telecommunication services. To implement
interconnection between MS and BSS, systematic rules and standards should be
established for signal transmission on radio channels. The standard for regulating
the radio channel signal transmission is called radio interface, or Um interface.
Um interface is the most important interface among the many interfaces of CDMA
system. Firstly, standardized radio interface ensures that MSs of different
manufacturers are fully compatible with different networks. This is one of the
fundamental conditions for the roaming function of CDMA system. Secondly, radio
interface defines the spectrum availability and capacity of CDMA system.
Um interface is defined with the following features:
l
Channels structure and access capacity.
l
Communication protocol between MS and BSS.
l
Maintenance and operation features.
l
Performance features.
l
Service features.
II. Um interface protocol model
Um interface protocol stack is in 3 layers, as shown in Figure 1-4.
Figure 1-4
Um interface layered structure