A resource management device, a resource management method, and a device and method in a communication system. The resource management device is used for managing opportunistic utilization of frequency spectrum resources of a primary system by a secondary system in the communication system, and includes: a reception unit configured to receive device information and a resource request of a target secondary system device among one or more secondary system devices in the secondary system; an available resource acquisition unit configured to acquire, in response to the resource request, available resource information of the target secondary system device on the basis of the device information of the target secondary system device, wherein the resource information includes indication information related to transmission waveform used for the target secondary system device; and a notification unit configured to notify the target secondary system device of the acquired resource information.