Applied Research Of Key Technologies On OFDM In Wideband HF Communication

According to the influence of HF channel on the data transmission, a HF wideband OFDM data transmission scheme has been put forward. This paper lays emphasis upon the two key technologies: time-frequency synchronization and channel estimation. In the Synchronization part, with the requirements of synchronization considered, a joint time-frequency synchronization algorithm is designed by using the CAZAC sequences. And in the Channel Estimation part, due to our scheme applied to the slow fading channel, the performances of the LS algorithm, the MMSE algorithm and the SVD algorithm are compared in a given slow fading channel. Taken the relatively low SNR scenarios into account, this paper will focus on several channel estimation algorithms for suppressing noise in transform domain, including DFT-based channel estimation algorithm and the edge value repetition and suppressing noise in time domain channel estimation algorithm. At last, an improved DFT-based channel estimation algorithm is proposed for our system.Finally, with MATLAB simulation, the system bit error rate is given. And the result shows that the designed system well meets the requirements of HF communication in low SNR condition. In addition, some modules of the system are tested by using the hardware and the results show that the performance is satisfying.