Femto what?

Today I installed a femtocell in my house. Yes, my humble abode is now officially a mini-tower on Sprint's cell network, courtesy of a $99 Airave.

Now based on my previous diatribe, you might be wondering why the hell I would do this. And of course I did it for no reason other than its an very odd but interesting gizmo, and I am the only kid on the block who has one, nyeah nyeah nyeah.

The Airave is a small white unit, roughly the size of a standard residential wireless router, but with a vertical orientation, with a single stubby antenna. It has 4 LEDs on the front, to indicate power, system, GPS, and WAN status. Yes, it has an internal GPS which the documentation states is needed to provide 911 services; the blogosphere states the GPS is truly present to prevent usage of the unit outside the USA.

The Airave has an RJ45 jack, and is attached to your broadband router via an ethernet patch cable (supplied). The initial power-up is documented to require up to an hour, but in my case I surrendered after 90 minutes. The GPS indicator had stayed red (blue indicates active), so I powered the unit off and connected the "optional" GPS antenna, which is a standard puck style unit. After connecting the GPS antenna, the subsequent power cycle took about 15 minutes for the unit to fully activate.

After activation, your cell phones connect to the Airave instead of directly to the Sprint network, and the Airave routes the calls thru your broadband connection to....somewhere. My understanding of the network topology is vague, but a decent diagram can be found here.

In the 2 hours (lol) that I have been using the unit, I have found that it dramatically improves cell reception inside my house. My Sprint service has been close to unusable inside the house, whereas now my family's Sprint phones routinely have 4 or 5 bars in all areas of the house, and the voice quality is very good.

I do have some remaining questions. First, the antenna does not seem removable. I wonder if this is hackable to install a larger and more powerful antenna, thus further increasing the reception and range of the unit. Second, there is no built-in security for this unit. Any Sprint phone in range can connect in via the Airave, and thus your neighbors can get a free ride on your Sprint minutes. While the allowed phone numbers can apparently be controlled by calling Sprint's service center, this seems like a poor solution. Lastly, my Blackberry is provided by a corporate program and is not part of my Sprint plan, and I wonder how the minutes usage is counted, exactly.

In summary, the unit seems to perform its function well, and my original diatribe about the financial nonsense-icalness of the unit is balanced by the fact that it actually works.