Two years after the devastating Sendai earthquake and subsequent tsunami rocked north-east Japan, mobile operator Softbank has updated its floating mobile phone base station system to include satellite comms for extra resilience.
Networks faltered after the 2011 quake, with mobile phone towers knocked out of action. Softbank’s answer was an emergency mobile relay system involving a helium-filled balloon floating around 100 metres off the ground.
Said balloon was fitted with a 3G base station capable of transmitting a signal in a radius of more than 3km and microwave transmitter for backhaul.
This transmitter can apparently beam down to a ground truck up to 5km away which is usually plugged into the rest of the cell infrastructure, while power to the balloon is supplied through the same cabling that keeps it from floating away.
Softbank has since trialled an updated version of the system in which the truck-based ground station is set up to receive satellite communications. Such a system could be necessary in the event of a catastrophic natural disaster which knocks out most cellular infrastructure.
“In the case of a big disaster as long as we can see the sky and get the radio waves from the satellite then we can make our network available to people,” a Softbank spokeswoman told The Reg.
The network operator is currently finalising plans to place ten such balloon-based systems at various locations across Japan, she added. ®