Base station promo image (via PA Consulting Group)
For the sole purpose of exposing the power of cheap off-the-shelf solutions, and to inspire others, engineers from "PA Consulting Group" created their own personal mobile phone network using a Raspberry Pi. Besides the Lego supercomputers and arcade systems, this has to be one of the most impressive use of a Raspberry Pi I have seen so far. The engineers ultimately succeeded in shrinking a cell phone reception tower into the Pi connected to a radio interface.
All this was done within a special facility at PA labs. This was to ensure no laws were broken regarding the licensed spectrum belonging to mobile operators. Using an antenna and some circuitry the mobile phone frequencies get converted into a digital signal the computer can handle. From there, two open source software programs handle and route voice and SMS traffic through the Pi.
Although the system sounds simple, the software took lots of optimizing to work in the way they needed it to. The technology experts at PA consulting had to use every bit of experience they had to get parts of the code to run fast enough to process the signals. The two open source platforms used are OpenBTS which implements the GSM phone standard, and FreeSWITCH which handles and routes calls in a similar way as Skype does. In addition, the engineers also had to create a few software features of their own using Python.
This project certainly works to expose the power of the Pi, and it doesn't disappoint. Frazer Bennett, a technology expert at PA stated, “This proves what can be achieved through low-cost off the shelf systems. Just imagine the other possibilities that other such low cost technologies could inspire across other sectors and industries.” I think the next exciting thing we will see come from the Pi will be through the PA consulting-sponsored Pi-making challenge. The deadline is the 31st of this month, so it will not be to long until we see more delicious Pi creations.