1. A communication method with devices, comprising:classifying the devices into groups based on device's property;
performing resource allocation to a first device group knowing an already expected data information content without authentication;
performing authentication on a second device group not knowing the already expected data information content and then performing resource allocation to the second device group;
transmitting a signal including resource allocation information based on the resource allocation to the devices; and
receiving data from a device in the first device group and/or a device in the second device group through the allocated resource,
wherein the expected data information content is an amount of bits to be transmitted by one of the respective devices.