A first communication device for handling a real-time data transmission, comprising: an identification module, for identifying at least one first real-time data, and for storing at least one first arrival time of the at least one first real-time data; a prediction module, coupled to the identification module, for predicting a second arrival time of a second real-time data according to the at least one first arrival time and a prediction algorithm in order to generate a first prediction result; a scheduling module, coupled to the prediction module, for scheduling the second real-time data according to the first prediction result to generate a first scheduling result; a reservation module, coupled to the scheduling module, for reserving a transmission resource according to the first scheduling result; and a transmission module, coupled to the reservation module, for transmitting the second real-time data according to the first scheduling result via the transmission resource; wherein the operation of identifying the at least one first real-time data comprises: determining whether an Ethernet type of at least one received data and an Ethernet type comprised in a real-time data configuration are the same in order to generate at least one comparison result; and determining that the at least one received data is the at least one first real-time data when the at least one comparison result indicates that the Ethernet type of the at least one received data and the Ethernet type comprised in the real-time data configuration are the same; wherein the transmission module is further configured to transmit a clear to send, CTS, data to a second communication device for informing the second communication device to stop transmitting in a guard time before transmitting the second real-time data. an identification module, for identifying at least one first real-time data, and for storing at least one first arrival time of the at least one first real-time data; a prediction module, coupled to the identification module, for predicting a second arrival time of a second real-time data according to the at least one first arrival time and a prediction algorithm in order to generate a first prediction result; a scheduling module, coupled to the prediction module, for scheduling the second real-time data according to the first prediction result to generate a first scheduling result; a reservation module, coupled to the scheduling module, for reserving a transmission resource according to the first scheduling result; and a transmission module, coupled to the reservation module, for transmitting the second real-time data according to the first scheduling result via the transmission resource; wherein the operation of identifying the at least one first real-time data comprises: determining whether an Ethernet type of at least one received data and an Ethernet type comprised in a real-time data configuration are the same in order to generate at least one comparison result; and determining that the at least one received data is the at least one first real-time data when the at least one comparison result indicates that the Ethernet type of the at least one received data and the Ethernet type comprised in the real-time data configuration are the same; determining whether an Ethernet type of at least one received data and an Ethernet type comprised in a real-time data configuration are the same in order to generate at least one comparison result; and determining that the at least one received data is the at least one first real-time data when the at least one comparison result indicates that the Ethernet type of the at least one received data and the Ethernet type comprised in the real-time data configuration are the same; wherein the transmission module is further configured to transmit a clear to send, CTS, data to a second communication device for informing the second communication device to stop transmitting in a guard time before transmitting the second real-time data.