Reference Manual

Radio Transmission
SW Power Boost
In order to improve downlink performance, a BTS, without Filter
Combiner,can be configured for TX diversity.
Note: Only the following macro configurations are supported:
RBS 2101, RBS 2102 and RBS 2202 with configurations
1x2, 2x2, 3x2, CDU-A for 900 MHz, CDU-A with TMA for
1800 MHz and 1900 MHz.
Two transmitters connected to different antennas are then transmitting
with maximum power on the same frequency. One of the transmitters
has its bursts forwarded in time two bits compared to the other. The
MS receiver signal processing will then contribute to a downlink
performance gain of some 3 dB.
SW Power Boost is initiated when the master transmitter is configured
on A-bis to a nominal power value 2 dB or higher than the maximum
nominal power defined for the TX, and no Operation and Maintenance
Link is established to the slave transmitter. The slave is the next
transmitter in the same antenna system.
Faults from one of the two TX instances will result in that a class 2
fault, TX Diversity fault, is reported from the TX via fault reports over
A-bis.
33.4 Operational Conditions
Frequency band
Transmitters for the GSM 900 band are capable of operating in the
extended GSM 900 frequency band, 925 – 960 MHz.
The combining system supports the primary GSM 900 band, 935 –
960 MHz or the extended GSM 900 frequency band, see /GSM:05.05:2/
depending on equipment.
Transmitters for the GSM 1800 band operate in the GSM 1800
frequency band, 1805 – 1880 MHz. See /GSM:05.05:2/.
Transmitters for the GSM 1900 band operate in the GSM 1900
frequency band, 1930 – 1990 MHz. See /JTC:5.1/.
Nominal power
The nominal power is the maximum output power the transmitter is
allowed to use.
Nominal power is defined as the power level at the output of the
transmitter, and is set at configuration. It is possible to set 7 values in
2 dB steps with accuracy according to /GSM:05.05:4.1.2/ for GSM 900
and GSM 1800 and /JTC:5.3.3/ for GSM 1900.
Output power
The output power is measured at the TX reference point, see Section
33.2 Concepts on page 260.
The output power is configuration dependent and is described in the
chapter "Radio Configuration, RBS 2000 Macro".
262 (421)
EN/LZT 720 0008 R1A
2001-06-26
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