隨著無線通訊技術的發展，不管是在LTE(Long Term Evolution)的第四代行動通訊，或著在未來5G行動通訊中，正交分頻多工(Orthogonal Frequency DivisionMultiplexing，OFDM)的技術還是十分重要的。本論文將會針對以分時雙工(Time Division Duplexing ，TDD)的正交分頻多工上行及下行鏈路系統，及調變原理做介紹。 而本論文將以軟體無線電方式，實現TDD OFDM上行及下行鏈路系統的發射機與接收機之間的溝通對傳(無人機與地面站對傳)。透過使用軟體無線電平台，可以即時的在單一頻率不同時間上，完成使用者與基地台的溝通，並可以觀察空中的訊號，經過空氣後發生的變化與不同大小增益帶來的影響，探討本論文系統的品質。 ;With the development of wireless communication technology, whether in the fourth generation of mobile communication of LTE (Long Term Evolution), or in the future 5G mobile communication, the technology of Orthogonal Frequency Division Multiplexing (OFDM) is still very important. This paper will introduce the TDD OFDM uplink and downlink systems and modulation principles. In this paper, the communication between the transmitter and the receiver of the TDD OFDM uplink and downlink system is realized by software radio (the user and the base station are transmitting). Through the use of the software radio platform, users can communicate with the base station at a single frequency and at different times, and can observe the signals in the air, the changes after the air and the effects of different size gains to discussion on the quality of the signal and system, etc.
