Free network for the Guanyem Barcelona event in Sants

The GuifiSants community provided Internet connectivity using the qMp mesh to stream the event live - 25/09/2014

In early September 2014 we received a request from the Guanyem Barcelona movement where they asked us to give support for an event [1] on the 16th September at Cotxeres the Sants, with the idea of streaming the event live on Internet. There wasn't any network available at the venue and the 3G connection might not work if the site was crowded. Volunteers of the GuifiSants [2] community evaluated the options and decided to make it happen. A priori, it seemed a difficult and risky task, since the place was geographically complex (in the coverage sense), the bandwidth requirement was quite high (1 Mbps steadily) and the expected audience was about 1000 people. As you may know, the spectrum used in WiFi technology is narrow and gets saturated easily; adding the transmission power restrictions and the low through-wall signal penetration at 5 GHz the challenge was there.

To brind the GuifiSants network coverage to the venue premises we build the mobile outdoor node shown in the pictures below with the following specs (material gently provided by Routek SL [3], approx. bill of materials cost: 300 €):

  • 2x TP-Link WDR-4300 (dual band 2.4/5 GHz)

  • 1x Compex WP72 (single band 5Ghz)

  • 1x Power Gorilla 21Ah

  • Both routers had qMp installed

Using the GuifiSants qMp mesh network of the Sants district, the mobile node was placed close to the entrance of the Cotxeres de Sants building, the Compex router linked with the closest static node (at Plaça Ibèria) ant the TP-Link router provided the WiFi coverage inside the venue, where another TP-Link router provided connectivity to the computer actually streaming the video. The final map is shown below.

The available bandwidth was quite a surprise for us, close to 6 Mb/s (symmetric) before the event started and around 3 Mb/s while it took place with around 1,000 people in the venue.


Finally, the video streaming worked perfectly during the two hours that the event lasted, with a constant upload rate of 1 Mb/s. It was a big success both for the project and for the participative, citizen self-government process in Barcelona. Thanks to all the citizens that, altruistically, make the Free Network possible, more than 30,000 people could watch the live stream of the event headed by the activist Ada Colau.

Source: (25th September 2014)




Categories: Networks, Community