Reference Manual

Table Of Contents
Radio Congurations, RBS 2206
Filters, amplies and distributes received signals to receivers
belonging to one BTS.
4.5.1 Isolation Values
The RF isolation between the antenna reference points within any
conguration is required to be at least 30 dB. See industry standard /
GSM:05.05/.
4.5.2 RX Description
The receiver system performance is conguration dependent.
Third-Order Intermodulation Products
Receiver sensitivity is reduced when a third-order intermodulation
product, generated by the radio transmitters in the RBS, is received at
the same ARFCN as the useful signal. This occurs when the distance in
frequency between two simultaneous transmitters is chosen in such a
way that a third-order intermodulation product is generated at the same
frequency as the operating frequency of one of the receivers in the RBS.
The receiver sensitivity reduction due to third-order intermodulation
products can be avoided with frequency planning.
No frequency planning is needed for intermodulation products of higher
than third-order.
4.6 Basic Congurations
The GSM 900 and GSM 1800 congurations meet the GSM
requirements, except where otherwise stated.
The capacity of a conguration is dened at the TX and RX antenna
reference points at the RBS border. There is an X close to every
reference point in the gures. The RBS border is not included in the
gures.
The equivalent output power with SW power boost (TX diversity)
congured is the original output power specied for the basic
conguration increased with typically 3 dB, if separate TX antennas are
used. The congurations that support SW power boost are listed in
Section 4.7.3 SW Power Boost Congurations with CDU-G on page 73.
Functional views of radio signal paths for various congurations are
shown in Figure 6 on page 36 upto and including Figure 24 on page 64.
Only components necessary to illustrate the conguration are shown.
In some congurations, the radio signal paths can differ depending on
where in the cabinet the basic conguration is used. The gures show
fully-equipped cabinets with two or three BTSs, that is two or three
basic congurations are shown in the same gure. These are different
physical implementations of the same basic conguration, not different
congurations. The second BTS is drawn with dotted lines to show
how an SCC in a fully-equipped cabinet is connected.
EN/LZT 720 0008 R1A
2001-06-26
35 (421)
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