A data communication method and system for a mobile communication network includes an improved medium access control mechanism for improving QoS and power efficiency of network components while maintaining channelization effects. A data communication method for a wireless communication network includes a coordinator and at least one network node according to the present invention includes the steps of broadcasting, at the coordinator, a beacon frame for informing the at least one network node of a duration of a superframe; transmitting a Guaranteed Time Slot (GTS) from the coordinator to the at least one network node for allocating timeslots; and transmitting a data frame from the coordinator to the at least one wireless network through the timeslots allocated to the at least one wireless network node.