Ericsson RBS 2106 Hardware Reference Manual page 183

RBS 2106 and RBS 2206
8 Co-Siting with TDMA RBS Using an ASU
The ASU is used for co-siting with a TDMA RBS, more specifically RBS 884
for 800 MHz and 1900 MHz, and RBS 882 for 800 MHz only. The unit allows
a TDMA cabinet to share receiver antennas with a GSM cabinet. The ASU is
installed in a dTRU based GSM cabinet.
The implementation is for 800 and 1900 MHz. The end configuration differs
for different site configurations of the TDMA RBS. One-, two- and three-sector
sites can be supported. In the case of two- or three-sector sites, the figures
below only show one part of the RBS.
 6HSDUDWH 7; DQG 7ZR 6HSDUDWH 5; $QWHQQDV
The original antenna configuration of the TDMA RBS is TX + RX + RX. When
co-siting is configured, the antennas are moved from the TDMA RBS to the
dTRU based RBS. The dTRU based RBS can be prepared for co-siting already
at the factory. The RX paths to the TDMA RBS will go through the ASU.
By moving the receiver antennas to the dTRU based RBS, it is possible to
benefit from minimum interference with the old equipment.
)LJXUH 
If TMAs are used in the original configuration, they are replaced with
dual-duplex TMAs (ddTMAs).
EN/LZT 720 0318 Uen R1A
TX RX RX
TDMA RBS
6HSDUDWH 7; DQG WZR VHSDUDWH 5; DQWHQQDV QR 70$V
TX
Co-sited
RX A
TDMA RBS
RX B
Radio Configurations
TX/RX TX/RX
dTRU Based
RBS
P008526A
85 (90)