Ubiquisys, the Swindon-based company responsible for the tiniest of mobile base stations, has raised another $19m in VC cash, bringing the total to almost $86m.
That money hasn't arrived all in one go - Ubiquisys started spending other peoples' money with a cash injection of $12m back in 2006, followed by $25m a year later and two more rounds since then.
But that's a reflection of an industry which saw huge potential, failed to realise it, and then noticed the technology could revolutionise mobile in an entirely different way.
Femtocells are self-configuring base stations, starting with a list of their owner's licensed bands they monitor local radio conditions to find a suitable slot in which to operate, and then backhaul calls and data over the public internet to the network operator.
Vodafone's Sure Signal is the best known in the UK, though Three and O2 have similar offerings for good customers who might otherwise go elsewhere. But early versions of the tech were flaky, and customers balked at having to install (and, in some cases, pay for) their own connectivity so Femtocells have failed to change the world as predicted.
A change of name, however, has reignited interest in the industry.
"Small Cells" are now all the rage, with network operators reducing the footprint of each cell to increase capacity, but that gets expensive as fitting a real base stations requires costly cabling (for the backhaul) and competent installation engineers.
As Small Cell just needs an Ethernet plug and some power, and the Ethernet is optional if a high-frequency mesh is used for backhaul.
That enables enterprises to deploy their own campus-wide networks, in agreement with a network operator or using low-power GSM spectrum from Teleware or similar, but it also enables network operators to manage capacity better.
The very latest thing in mobile is "hetronets", where an operator will have two networks covering the same space and use them depending on demand. So a stadium or conference centre might have a Small Cell network, which remains powered down most of the time, but once the venue fills up and the macro gets overloaded a Small Cell network kicks in and backhauls over standard IP connectivity.
That Small Cell network can be installed by anyone who can tell the difference between mains power and Ethernet, and configure itself to make best use of the frequencies available, and it’s boxes that Ubiquisys wants to sell.
The new funding will, according to Ubiquisys, let it devise dual-generation boxes supporting 3G and 4G (LTE) technologies, ready for the 4G networks proliferating around the world, just as long as this revolution doesn't get stalled like the last one. ®