User's Manual

Table Of Contents
Installation, Operation and Service Manual 90DIB500R41IM_FCC02 99.1 49
DIB-500 R4.1 Product description
Constituents
3.1.5.2 Overview of possible functions
In the ACCESSNET
®
-T IP, the available services and performance features are com-
bined in form of so-called functional units. These functional units available for the
present product are described in the following sections.
Depending on the respective network configuration, the DIB-500 R4.1 can provide the
following functional units:
| Base Station Function (BSF)
| Switching Controller Function (SCF)
| TETRA Vocoder Function (TVF)
| Application Gateway (AGW)
| Packet Data Gateway (PGW)
| Telephony Gateway (TGW)
Base Station Function (BSF)
The Base Station Function (BSF) is a functional unit of the ACCESSNET
®
-T IP and pro-
vides the air interface in compliance with the TETRA standard (Terrestrial Trunked
Radio, TETRA).
The air interface facilitates the communication (voice and data) between mobile stations
such as hand-held mobile radios, data radios (Remote Terminal Unit, RTU) and radio
dispatcher workstations. The radio channels for this purpose are generated via trans-
ceivers of the base stations that are available in various frequency ranges. The traffic
and packet data channels are dynamically occupied. Signalling and short messages
(SDS) are transmitted via statically configured control channels (MCCH and, if neces-
sary, SCCH).
Switching Controller Function (SCF)
The Switching Controller Function (SCF) is a centralised function block of the
ACCESSNET
®
-T IP and ensures the IP-based routing function between the network
constituents of an ACCESSNET
®
-T IP network and the gateways (telephone network,
application and packet data).
The SCF can be used flexibly on different network elements/platforms and combined
with other functional units. If a distributed switching architecture is used in an
ACCESSNET
®
-T IP network, gateways to applications could be implemented locally at
any network constituents. Depending on the requirements of the ACCESSNET
®
-T IP
network, the routing functions are also available to application and telephone gateways.
TETRA Vocoder Function (TVF)
The TETRA Vocoder Function (TVF) serves as a converter (encoder/decoder) for voice
streams between the TETRA system and an external system such as a telephone net-
work. With the aid of the TVF, the voice between the TETRA format used (ACELP, Alge-
braic Code Excited Linear Prediction) and the G.711 format (A-Law or µ-Law) is
recoded. The TVF is required for the Telephone Gateway (TGW) functional unit. The
TVF is also required for the Application Gateway (AGW) functional unit if the voice con-
nection of the application is to be implemented via G.711 instead of via the TETRA
codecs.