Someone posed me a question recently relating to poor coverage in their office. Calls and text messages were being missed. Surely a femtocell would be the obvious, quick and low cost answer to the problem? Sadly, I fear this is an unusual case where femtocell technology doesn’t apply.
It’s US based
Unlike other countries, all femtocells in the US are fitted with GPS. This is for several reasons:
- To synchronise the signal with an accurate timing source, essential where handover to outdoor cellsites is required. This is essential for CDMA mobile networks (such as Verizon or Sprint); other network technologies found elsewhere don’t require this.
- To provide an accurate location for use when reporting emergency calls
- To determine if the femtocell is in an area where the network operator owns licensed spectrum and so determine whether to work, and if so at what frequency
In order for the femtocell to work in the US, it needs to receive a GPS signal. The receivers used are very sensitive so do work indoors in many cases. A stronger signal can either be achieved by locating near to a window or using an antenna cable connected to the device.
In other countries, the GPS receiver is not required. Other methods are used to determine where the femtocell is located (such as sniffing for signals from outside cellsites, deriving this from your internet connection/IP address etc.). They would still be able to be used in this situation.
It’s completely underground
The office in question was a sealed lab, based underground. It had no windows and no easy access to the sky. In these cases, the femtocell wouldn’t be able to work out where it was and would refuse to operate.
Perhaps a cable could be used to run an antenna up to ground level, enabling GPS reception. If this was the case, then service could be provided. For some situations, this may not be as easy as it sounds.
This is a corner case
For most users with a basement that has poor coverage today, a femtocell located at ground level would emit enough signal to penetrate downstairs and throughout the building. So it’s a pretty unusual case.
As stated above, I don’t think this applies for femtocells in other countries
Let me know if you disagree, otherwise it’s back to the traditional wireline phone for this office.