A communication system includes a first remote terminal unit (RTU) outputting first RTU data, a second RTU outputting second RTU data, and a remote control center applying a first RTU weight, which is a weight for the first RTU, to the output first RTU data and a second RTU weight, which is a weight for the second RTU, to the output second RTU data, and generating state estimation information for the first and second RTUs on the basis of the first and second RTU data to which each of the first and second RTU weights are applied.