Signal Properties under Multi-Carrier Chaos–Shift Keying

Abstract

In recent years, increased demand for high-quality multimedia services requires increasing the wireless communications application data rates and be more reliable and secure. To meet this request, the researches related to Multi-Carrier (MC) transmission technologies have made considerable efforts in recent years because multi-carrier techniques can improve the data transmission rates. In this research, an overall study on performing Multi-Carrier Chaos Shift keying by using a technique Orthogonal Frequency Division Multiplexing (OFDM) is presented. A multi-carrier system simulation is designed because of the limited speed provided by Chaos Shift keying (CSK) due to the spreading factor. To increase security in this system; the chaotic sequence was generated by proposed to modify on one of the well-known chaos generators that is a tent map. The performance test and the security analysis were carried out using the Bit Error Rate (BER), Mean Squared Error (MSE), correlation test; the chaotic characteristics of the chaos generators sequences using are tested the Lyapunov Exponent. Results have showed the proposed tent map the autocorrelation is like a delta function, so that it appears as a noise that is difficult to discern the information carried by signal, it is much more sensitive to change the initial state and control parameters, where the proposed tent map provides better chaotic properties for encryption such as greater Lyapunov exponent, compared with well-known chaos maps (Logistic map1, Tent map, Quadratic map), it provides a lower Bit Error Rate (BER) performance than a tent map. In addition, the proposed method to multi-carrier CSK system with various Spreading Factors (SF) values outperforms the CSK system in improving the data transmission rate.