A communication apparatus is provided. The communication apparatus comprises an external memory device and a communication unit. The external memory device stores software functions corresponding to a predetermined application profile of the wireless communication system. The communication unit comprises: a radio transceiver module transceiving radio frequency wireless signals and converting the radio frequency wireless signals to or from baseband signals; a baseband module converting the baseband signals to or from digital signals and processing the digital signals; an internal memory device storing a firmware programmed for controlling the radio transceiver module, the baseband module, and performing a physical layer protocol and a data link layer protocol of the wireless communication system; and a microprocessor accessing the software functions via an interface and executing the firmware and the software functions when implementing the predetermined application profile.