All I know of communication on the battlefield when you can't talk is what I see in the movies. It apparently involves many hand signals from what I can tell. A new system that uses belts loaded with sensors and feedback from vibrating motors may replace those hand gestures in the future. It sounds like some of the tech that is in video games today. The solider would wear the haptic feedback belt and it could guide them along a route without the fighter having to look down to follow a GPS or map.
The belt comes out of the Army Research Office and it would vibrate various motors to route the solider using signals sent from a GPS device. Rather than having to look at a glowing GPS screen the belt would just vibrate to tell the solider when to turn and in what direction. The vibrating motors in the belt are called tactors and they are spaced at 45-degree intervals. The belt vibrates the tactor that is in the direction the user needs to go.
The system has to have waypoints set for the solider to follow. The belt could also be linked to a glove that a commander would wear to transmit hand gestures to all the soldiers at one time. It would be able to turn hand gestures for halt and move out for instance into pulsing of all tractors at once and pulsing from front to back respectively. The belts would also be able to be directed from a command center as well allowing commanders with more information to route the squad from far away without needing to fire up a radio.