What exactly are these?

[CitadelCore]

Hey! Found these on the roof of a public toilet, somewhere in Hong Kong. I think they're some kind of LTE transmission system, but I'm not sure. Looks a bit excessive. One even looks like an oversized Xbox 360!





Four huge horizontal boxes? Weird.

[Richard Crowley]

Looks like a typical multi-service cell site.  You might find more clues from the appearance of the antennas (directional dishes vs. non-directional, etc.)

[CitadelCore]

Thanks for the reply mate. The cell antennae seemed to be non-directional (instead of a dish, they were a white rectangular box).
Any ideas on what the devices specifically are, or what role they play in the transmission system?

[Richard Crowley]

The entire global network of cellular phones depends on millions of these cell sites. This is a rather small, outdoor installation. It is more common to see larger weather-proof racks with transmitters and receivers bolted inside. And in even larger installations small buildings full of gear.  It is rather unusual to see all those individual enclosures out in the weather like that.

Google Images for "cell site shelter". You will see a range of installations from individual racks less than 1m tall, to pre-fab buildings as big as a large garage.

 

[SeanB]

Outdoor base stations, the boxes strapped together are antenna splitter matcher units, which provide the multiband signals from the antennas to the transceiver unit, and there is active electronics in those along with more in the directional antennas. The whole lot is probably Huawei made. The big rectangular boxes will contain a power supply which supplies 48VDC and which also does battery back up, along with having the fibre transceivers for the backhaul. The antennas are directional, they contain a few separate steerable antenna arrays inside to make multiple sectors to increase traffic density.

I have the same layout by me, just all indoor units for lower maintenance, as the whole lot is kept at 24C by dual airconditioners and a management unit.