In many applications such as automobiles on busy highways, if a lot of vehicles on road are equipped with Doppler LIDARs to help improve driving safety, no matter human-driven or autonomous-driven, when multiple LIDARs are simultaneously illuminating an object, the LIDARs signals will interfere with each other. Avoiding interference between them is a hard task. The disclosed invention of “Doppler group LIDAR” will allow LIDAR devices of this kind to inherently work together in “physical layer” without interfering one another, without sacrificing performance, and without having to rely on higher layer protocols to achieve these goals, so that all LIDARs of this kind interoperate easily and reliably.