The Research Of OFDM Multi-Carrier Communication Technology Based On Software Radio And Applications

Very High Frequency/ Ultra High Frequency (VHF/UHF) communication is good at mobility and flexibility, and it also appears with features of moderate transmitting power, reasonable equipment cost, very sound anti-destroying ability and great security. So, it is usually adopted as an important tool for long distance communication and command system by military department and other organizations. However, because of much more complicated factors such as multi-path-time-delay & fading, Doppler-frequency-shift, frequency-shift-spreading, white noise similar to Gauss-distribution and radio station interference, the communication reliability and performance are gone down. These limit its application in ever-increasing communication demand. This paper focuses on some technical difficulties encountered in the long distance wireless communication and tackles the task by applying OFDM (Orthogonal Frequency Division Multiplexing) techniques in the communication system. This hence improves the overall system performance in communication by overcoming the effects like multi-path fading and Doppler spread in the frequency domain.OFDM is a special case of multi-carrier digital modulation technique that allows different sub-carriers which are orthogonal narrow band signals overlapping. One of the main advantages of OFDM is that it efficiently resists the multi-path propagations those are inevitable in wireless radio communications.Software radio (SDR) is a new system structure in wireless communication that was put forward nowadays, which takes hardware as a base platform for wireless communication and depends on software as much as possible to realize its function.OFDM and SDR are both the charming core technology for future mobile communication. This paper mainly focuses on the combination of OFDM system with the SDR technology and presents OFDM multi-carrier transceiver system scheme based on SDR platform. And this paper also discussed several key problems that OFDM system needs to solve in VHF/UHF communication, offered the system model designation, accomplished the simulation and realized a Base-Band hardware platform.