The Internet Connection
During the Tour across Italy, ARGO broadcasted a live
video stream to the Internet.
To accomplish this target a permanent link to the Internet
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:
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
But the most important capability for our application is that
EQL dynamically adapt
the network traffic according to the number of working serial links.
Another personal computer was installed on ARGO; it was equipped
parallel port Quickcam Color
camera and two GSM modems able to work up to 9600 bps using the MNP10-EC
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.
- low bit-rate band for transmission (usually 9600 bps, namely a little
more than 1 kbyte/s);
- high variability of the bandwidth during movements;