Hi, Asher,
It is what is more precisely known as a
cell base station. They consist of a number of transmitter-receivers and an array of antennas. It is the fixed radio installation that serves a
cell within a cellular wireless telephone system.
Of course, each one is a "site" (or, more precisely, is at a site), so somehow it has become most common in the industry to call them
cell sites.
Among civilians, these are today most often called "cell towers" since very often (but hardly always) they include a tower to support their antennas.
But of course the antennas may be supported on a building wall, or a building parapet, or a railway bridge, or a water tank, or even (as we see above) on a grain elevator. So the word "tower" doesn't even always fit.
I always call them
cell base stations.
Best regards,
Doug