A next-generation wireless smartphone network can stream video, blaze through the Net ... and steer your car into a ditch? Super-fast “fourth generation” networks carry data at speeds of up to 1 Gigabit per second. But the new network from LightSquared may take the high-flying GPS network to zero Gbps -- potentially preventing air-traffic control towers from keeping track of aircraft, the military from accurately relaying locations or ambulances from showing up at the right house after a 911 call.