Directional Cell Site

The directional cell-site utilizing three sectors is one of the most popular
cell site configurations utilized in the wireless industry, next to the omnicell.
The three-sector cell is one that has sectors that cover 120 degrees
each, thus having three sectors makes a full circle.
There are a multitude of combinations for transmit receive that can be
used for establishing a three sector cell site. However, the following example
is the more basic configuration that is used and involves three antennas
per sector shown.

The configuration has a single transmit and two
receive antennas per sector. Naturally the amount of receive and transmit
antennas can change depending on the technology implemented for 2G,
2.5G, or 3G. For example iDEN 2G systems typically involve three antennas
per sector, but all three are usually duplexed to keep the antenna count
down while at the same time enabling for three-branch diversity reception.
When designing antenna placements for a site, it is strongly recommended
that future configurations be considered at the onset of the design
process. For instance implementing 3G services may require the use of a
separate Tx antenna and possibly Rx antennas.