Provided are a wireless network system and a method of transmitting/receiving data in the wireless network system, which separately set a period where a packet for requesting and approving bandwidth allocation of a network in a super frame period is transmitted/received, and as a result, transmit/receive data through the allocated bandwidth. Also provided is a wireless network coordinator, which includes an MAC unit which generates a beacon frame for organizing a super frame including at least one or more channel time blocks, and bandwidth management unit which sets a specific channel time block among the channel time blocks as a period where a bandwidth allocation packet in the network is transmitted/received, and a physical unit which transmits the beacon frame including information on the setting by the bandwidth management unit through a designated communication channel.