Research On Single Carrier With Frequency Domain Equalization In High-frequency Communication

Currently, the development of communication technology via High Frequency have an important statue either in civil or military purpose, since it has the advantage of simple device, high practicality, low cost, long transmission distance and so on. Short-wave communication mainly relies on ionosphere, so the variety of it causes vital influences on the signal to transmit, and corresponding measures must be taken to deal with it at the receiver. Now, the Time Domain Equalization and Frequency Domain Equalization are the two main techniques. Single Carrier with Frequency Domain Equalization (SC-FDE) is able to roughly resist the badly channel condition by constructing a reverse channel frequency response to compensate the received signal. In order to apply it in the short-wave communication, the features of channel, such as effect of multi-path, Doppler effect and time-variety, must be taken into account first, and then design a proper transmission scheme.This paper is on the background of short-wave transmission, based on the technology of SC-FDE, deeply analyses the feature of the ionosphere and theory of Frequency Domain Equalization, and advanced a combination of channel and single carrier system. Then simulation is done by constructing channel model. So the paper mostly discusses on characteristic of channel and SC-FDE. The main contents are showed below:1. It analyses some vital feature of ionosphere channel, including effect of multi-path and Doppler Effect. And we select Watterson channel model to illuminate it based the conclusion we get.2. It expounds the theory of SC-FDE and some related technology in detail, such as cyclic prefix (CP) to inserted, arithmetic of channel estimation, arithmetic of frequency domain equalization and so on. And then do some improvement based on it. We also compare the performance of SC-TDE (Single Carrier with Time Domain Equalization) and that of SC-FDE, in order to illuminate the superiority of SC-FDE system.3. According to the ionosphere channel, we design a reasonable frame format for a SC-FDE system. And also propose a method to compensation when the length of CP that inserted is insufficient. At last, we prove it by simulation.According to the simulation result, the proposed method has a fine performance and the frame-format we design can exhibit the advantage of SC-FDE system, for it has utilized the traffic perfectly and has a good performance. Therefore, it guarantees the reliability and stability of system, and can be used in the real High Frequency Transmission.