Node B Antenna Configuration

The Node B hardware determines the antenna configuration. The Siemens/NEC Node
B shown in Figure 11.3 can either be used on its own supporting one omnidirectional
antenna (1 × 360°) or with three units mounted on a pole to support a three-sector site
(3 × 120° beamwidth antennas).
All other Node Bs in this particular vendor’s range at time of writing are floor
mounted, mainly because they are too heavy to wall mount or pole mount. The example
shown in Figure 11.4 weighs 900 kg and occupies a footprint of 600 × 450 mm and
is 90 cm high. It can support two carriers across three sectors with up to 30 W per carrier,
sufficient to support 384 voice channels.
The same product can be double-stacked with a GSM transceiver to give a 1 + 1 + 1
+ 6 configuration, one 5 MHz RF carrier per sector for UMTS and a 6 RF carrier GSM
BTS, which would typically be configured with 2 × 200 kHz RF channels per sector. The
combined weight of both transceivers is 1800 kg and combined power consumption is
over 2 kW.
Afinal option is to use one of the family of Node Bs illustrated in Figure 11.5. These
can be configured to support omnis (360°), four sector (4 × 90° beamwidth antennas),
or six sector (6 × 60°), with RF power outputs ranging from 6 W to 60 W per RF carrier.

The configuration can also support omni transmit and sectorized receive (OTSR),
which has the benefit of providing better receive sensitivity. The physical size is 600 ×
450 mm (footprint) by 1400 mm high, and the weight is 1380 kg. Outdoor and indoor
versions are available. 244