High Level Security of Image Transmission through STBC-COFDM System
International journal of intelligent engineering and systems · 2022
In this paper, the security of image transmission through space time block coding (STBC)-coded orthogonal frequency division multiplexing (COFDM) is enhanced using two stage algorithms.In the first-stage, the samples scrambling algorithm using one dimensional (1D) chaotic map is proposed.In the second stage, the bits scrambling algorithm using chaotic map is proposed.The sample scrambling algorithm is designed depending on three types of 1D chaotic maps that are logistic-sine-cosine (LSC), sine-tent-cosine (STC), and tent-logistic-cosine (TLC) maps.In the bit scrambling algorithm, the stream bits are XORed with a pseudo-random bit generator (PRBG) produced by these chaotic maps using threshold method.Simulation results demonstrate that the image is retrieved with high quality for STBC-COFDM system and low signal to noise ratio (SNR).The image is unrecovered when the correct key is unavailable.For one level of security, the system using TLC chaotic map has the best performance compared with other chaotic maps.The bit error rate (BER) performance of the suggested system achieved 10 -4 at SNR=1, and 2 dB for (TLC, LSC) and STC, respectively.For two stages of security, the proposed system using STC chaotic map improves the BER performance with a gain of about 2 dB at BER=10 -4 compared with one stage of security.