Getting Started with OpenBTS

Chapter 4. From Single to Multinode

A mobile network with a single tower is infinitely more useful than one with zero towers. However, there comes a point where no matter how well that single tower is tuned, it cannot effectively cover a given area.

Tip

Because OpenBTS uses the same software stack to implement large and small coverage areas and has even been made to run on a Raspberry Pi, try to free your mind of the classic “cell tower” image. A tower could easily fit in a shoebox or blend in with your WiFi access point.

This chapter describes how to expand your network to multiple physical sites but still maintain a single logical network. This logical network will support Mobility and Handover as any commercial network would.

Mobility, Handover, and Roaming

There is some confusion among these terms. While they do mean very specific things, even experts in the field will throw them around in discussion and expect the other party to understand the correct meaning from the context. To clear up this ambiguity each term will be outlined briefly.

Mobility

Mobility is the ability of a handset to receive service on different physical base stations in an operator’s network. As the handset moves in three-dimensional space, the signal quality it receives from neighboring base stations will fluctuate. When the handset detects a significantly better signal from a neighboring base station, it sends an LUR to register or “camp” to the new base station. To differentiate, a periodic LUR at the same ...