| The broadband data link discussed in this thesis is developed for high-speed, highly efficient, and highly reliable transmission of information in such a complex interference environment, including multipath interference and all kinds of enemy interferences. The transmission rate is even more than 100Mbps. It poses new challenges for the anti-Jamming communication system, which is different from the traditional one. This thesis investigates the effectiveness of OFDM as a modulation technique for broadband data link, with a SC-FDE comparison. The main aim is to assess their suitability on three-ray multipath environment and the ant jamming performances are also analyzed. Comparative method is used.This thesis firstly analyzes the characteristics of wireless channel for broadband data link in brief, and points out that the wideband wireless channel is a frequency selective channel with deep fading. A three-ray multipath channel model is proposed. Then, after simple introduction of the basic principles of OFDM and SC-FDE, a whole simulation platform is constructed.ChapterⅣand chapterⅤfocus on the performance analysis of OFDM and SC-FDE. The analytical derivation of the Ber performance is derived and the results are compared with simulated results, which prove that the derivation is valid. In chapterⅣ, the performance of anti-multipath interference is reached. In chapterⅤ, the ant jamming performance of OFDM with various jamming types is analyzed, and the performance with equalization and coding are also given. The results show that: (1) In the absence of channel coding, SC-FDE substantially outperforms OFDM signaling. But the former technique suffers from strong sensitivity to channel estimation accuracy. (2) Partial-band jamming, pulse jamming and multitone jamming can maximize the error probability of OFDM system, and multitone jamming gives the most serious performance deterioration. For the SC-FDE system, only pulse jamming can does. Coding and interleaving can significantly improve their performance. Finally, the following conclusion is drawn: SC-FDE is more suitable for broadband data link, which is an asymmetric communication system. |
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