The Internet Connection

Video broadcast requirements

During the Tour across Italy, ARGO broadcasted a live video stream to the Internet. To accomplish this target a permanent link to the Internet was established.

The problem

A permanent link from a moving vehicle implies the use of mobile telecommunications facilities, such as GSM modems. Unfortunately the use of GSM modems for live video streaming compels to face the following constraints:
  • low bit-rate band for transmission (usually 9600 bps, namely a little more than 1 kbyte/s);
  • high variability of the bandwidth during movements;

The solution

In order to increase the throughput of the link the simultaneous use of two GSM modems has been studied. Two different techniques were conceived to exploit multiple phone lines: Both share the underlying idea of splitting the network traffic across multiple serial links. The former relies on the presence of homogeneous serial links. Conversely the latter can handle also links that feature different throughput and protocols. But the most important capability for our application is that EQL dynamically adapt the network traffic according to the number of working serial links.

The implementation

Another personal computer was installed on ARGO; it was equipped with a parallel port Quickcam Color camera and two GSM modems able to work up to 9600 bps using the MNP10-EC protocol. The computer runs the Linux operating system and a specific application that grabs images from the Quickcam, convert them in the jpeg format, and send them to our web server through the two GSM modems exploiting EQL.