How To Run An Open Soruce GSM Network
Posted by Savio Rodrigues
“Here at the amazing HAR2009 hacker conference + camp, I have the pleasure of operating a camp-wide GSM network.
Under license of the Dutch regulatory authority, we operate two BTS with two TRX each, forming the network 204-42. The BTS are positioned on the top of a hill, with the antennas mounted back to back on a tree, each covering about half of the HAR2009 camp site. Every transceiver runs at 100mW transmit power, which is the maximum output as per our license.
From that tree, we run AC power and a single E1 line down to the GSM tent, where it runs into the Linux PC that runs our OpenBSC software. “
For those of us who aren’t mobile phone networking experts, BTS stands for Base Transceiver Stations, TRX stands for transceivers and BSC stands for Base Station Controller.
OpenBSC is a GPL implementation of major components of a GSM network. Welte is one of the key developers behind OpenBSC, which aims to:
- provide a basis for experimentation and security research with GSM from the network side
- document, publicized and point out any security related issues that we find as part of that
- learn more about GSM networks on a lower level, particularly the practical aspects with real-world equipment
Unfortunately, the project is not interested in:
- building a stable/reliable BSC/MSC for deployment in actual networks
- building something that follows the GSM spec to the last detail
- disrupting actual commercial GSM network
Since a government issued network bandwidth license is required to run a GSM network in most countries, few of us will never run our own open source GSM networks. Although it seems that countries like Russia allow the use of licensed frequencies for low-power indoor use. So the title of this blog is squarely targeted at readers in Russia. Kidding aside, I wonder while Welte and team aren’t interested in building a distribution that does fully implement the GSM specification. The use of OpenBSC on Linux could be targeted at telecom operators in emerging markets. Considering the growth in mobile phone usage in emerging markets, and network operator’s constant search for cost reduction, there could very well be a business here.
*Well, if you can get a government issued bandwidth license
About the Author: Savio Rodrigues is a product manager with IBM's WebSphere Software division. He envisions a day when open source and traditional software live in harmony. This site contains Savio's personal views. IBM does not necessarily agree with the views expressed here.