Generation of an efficient spreading code in Spread Spectrum Modulation (SSM) is always challenging due to considerations like optimum sequence length, physical layout of registers and power requirements. In this article, a design of a dynamic chaotic spreading sequence for application in a Direct Sequence Spread Spectrum (DS SS) based system with the considerations of wireless channels (Rayleigh and Rician) are presented. Generation of dynamic chaotic sequence for application in linear and nonlinear channels is done and a comparison with static chaotic sequence is presented. Evaluation of performance is done in terms of bit error rate (BER), computational time, mutual information and signal power for faded channel taking into considerations of different modulation schemes, which finally dictates the efficiency of the generated code. The performance of the generated dynamic logistic map-based sequence is compared to that obtained from Gold code under equivalent conditions.
Portable high-end instrument for in-vivo infrared spectroscopy using spread spectrum modulation
