Provided is a resource management system in a communication system including a plurality of systems having no right to use a first frequency band. The resource management system includes: a coexistence manager (CM) configured to manage the plurality of systems for the purpose of coexistence and frequency sharing of the plurality of systems in a frequency band available for the plurality of systems, when the available frequency band is detected in the first frequency band; a coexistence enabler (CE) configured to transmit and receive information of the plurality of systems and information of the CM; and a coexistence discovery and information server (CDIS) configured to support the CM to control the plurality of systems. The CM performs channel classification for the first frequency band based on channel information of the available frequency band, and allocates operating channels to the plurality of systems.