User's Manual

Open Information
DESCRIPTION 6 ( 19 )
ERA/RGN/PD Rikard Schönbeck 5/1551-HRB 105 102/1 Uen
ERA/RGG/TOC Jan Lundkvist 2002-05-28 B
Prepared (also subject responsible if other) No
Approved Checked Date Rev Reference
E
The Baseband and RF subrack are based on a common platform. The
backplane and Switch Core Boards (SCBs) use the ATM protocol for
communication within and between subracks. The cabinet’s BB and RF
subracks are also connected to each other through the Baseband Interface
Board (BBIFB) and the Radio Frequency Interface Board (RFIFB) carrying the
downlink and uplink traffic streams.
3.1 Connection Fields
Located on the cabinet top are the Connection Fields, which comprises an
Interface Connection Field (ICF) and connection interfaces for grounding,
power, and antenna jumper cables.
The ICF is used as an interface to the cabinet boards and contains the
interfaces for transmission, local O&M and Auxiliary Unit Hub (AU-Hub).
3.2 Capacitor Unit
The Capacitor Unit smooths the -48 Vdc supply, which powers the RBS. It
ensures that the RBS remains in operation during any short transient drop.
3.3 Baseband Subrack
The baseband subrack comprises an Iub interface connection with an RNC, the
MP cluster, and the baseband functionality. Baseband functionality consists
of transport channels, encoding and decoding, spreading of bits, combining
of channels, reception through a rake receiver, and searching and random
access processing. Subracks in a multi-subrack system are interconnected
in a star configuration in which one of the baseband subracks serves as the
main subrack. Equipping of the subrack differs depending on whether it is
the main or the extension subrack.
The following sections give a brief description of the boards in the subrack.
ETB
The Exchange Terminal Board (ETB) provides the connections for the Iub and
remote Mub interfaces. It serves as an interface between the transmission
cables and the Asynchronous Transfer Mode (ATM) switch on an SCB. The
type of ETBs depends on the transmission standard.
SCB
The Switch Core Board (SCB) contains an ATM switch and interfaces to the
ATM switch ports located on other boards via the backplane. An SCB can be
connected with up to four other SCBs located in other subracks.
The SCB also has a connector and filter for the system power. The system
power is distributed within the subrack via the backplane. The SCB also
supervises and controls the subrack fans.