User's Manual

Open Information

DESCRIPTION 7 ( 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

The two outer positions in a subrack are always reserved for SCBs. In larger

configurations with more than five subracks, Switch Extension Boards (SXB)

are added to the main BB subrack to extend the number of SCB connections.

RAXB

The Random Acces/Receiver Board (RAXB) comprises the baseband receiver

part, which takes care of decoding, searching and rake receiving for dedicated

and random access transport channels, and cell combination for softer hand

over. A soft hand over takes place when a UE moves from one sector to

another using the same frequency.

RAXBs within a baseband subrack share the load to achieve high availability. If

one RAXBs fails, the load is divided over the remaining RAXB. This ensures the

RBS continues to handle traffic, although with reduced capacity.

GPB

The General Processor Board (GPB) operates as an MP and contains and

executes the main part of the RBS software. It controls devices on boards and

in auxiliary units. The GPB has flash disk storage, an Ethernet connection and

an RS232 interface.

TXB

The Transmitter Board (TXB) comprises the baseband transmitter part for

handling transport channels, encoding, cell splitting, modulation and spreading,

and channel combining.

TUB

The Timing Unit Board (TUB) generates and distributes local timing signals.

BBIFB

The Baseband Interface Board (BBIFB) connects the baseband subrack to the

RF subrack. The connection carries the downlink and uplink traffic streams,

and timing signals.

3.4 Radio Frequency Subrack

The RF subrack contains all the RF processing hardware, except for the power

amplifiers and an optional ASC. It takes care of D/A and A/D conversion, RF

modulation and demodulation, RF carrier combining and splitting, and low

noise amplification for reception.

The following sections give a brief description of the boards in the subrack.

SCB

SCB is described at page 6 .

AIU

The Antenna Interface Unit Board (AIU) consists of a filter and control unit, and

a combiner and splitter unit. The filter and control unit provide the following: