Design And Study Of Novel Key Techniques In Secure And Reliable Wireless Transmission Systems

The identification friend or foe(IFF) system is applied to identify whether the target is friend or foe. The IFF system has been widely used in the warfare by many countries because the environment of battlefield becomes increasingly complicated. The system realizes the identifiecation of targets by undertaking secure communications between interrogators and tarnponders, in which the issue of both safety and reliability are critical. Based on those two issues, this paper focuses on the research of a novel IFF system. Based on the chaotic ciphers, the first part applies chaotic mapping to the design of interrogator's cryptosystem. And based on the characteristics of the polar code, the secode part applies the channel transmisstion of the interrogator's encrypted information.The main contents of this paper are as follows:(1) Based on the chaotic maps, the random key sequence and the nonlinear dynamic S box are generated, in which the key is by real sequence digitization of Henon-like chaotic map and to increase the uniformity and independence, the binary sequence is accordingly processed. As the important element, S box, is for the protection of security of block cipher, under the research of design method, the non-linear dynamic S box is constructed by Logistic-Tent chaotic mapping, whose non-linearity is preferably no less than 105 and the maximum value of differential uniformity is not more than 10.(2)Have designed the chaotic block encryption algorithm which is compatible with the Mark XIIA Mode 5 system, we analyze the block cipher with impossible differential crypt-analysis. First, 7-round impossible differential path is constructed for fixed S box and its cost of analysis is calculated from the perspective of data complexity, and block cipher of S box is analyzed by impossible differential crypt-analysis as well, which proved to be effective against differential cryptanalysis.(3)Polar code is a linear block code, which is based on channel polarization. After reseaeching theoretical knowledge of channel combing and splitting, and summarizing the encoding principles of polar code and the methods of how to select the information bits, as to selecting information bits, in this paper, a new method, channel converting method of how to select the information bits is proposed, which is. The method is suitable for the AWGN channel, then under AWGN channel, especially on simulating and discussing the decoding performance of SC decoding algorithm and BP decoding algorithm on different coding block lengths, different encoding rates and different maximum iteration times of BP decoding algorithm. Finally, the comparative analysis on SC decoding performance of polar code based on the channel converting method and BEC method is carried out by simulating.(4)In this paper, as to theapplication of polar code in wireless communication, the polar coded-cooperative system based on Plotkin's construction is proposed accorading to the half-duplex single-relay model. Compared with non-cooperative system and Nested construction, the simulation shows that the cooperative system which is based on Plotkin's construction can improve the performance of the polar code.