Implementation of Steganography in Speech Signal Using Spread Spectrum Modulation and Differential Method in Wireless Communication Systems

Abstract

In this paper, two steganography techniques to improve speech quality and clarity in communication systems and bandwidth expansion factor of the signal are designed and evaluated through simulation study. The two methods are: direct sequence modulation and differential methods. In order to achieve the desired speech quality, the speech signal parameters such as speech power ratio and the number of segments in a message were changed. Direct sequence modulation was performed by multiplying the source signal into a pseudo-random sequence. The resolution of the image depends on the size of the segment and the signal strength ratio. The second method is using differential methods. Similar to the first method, speech signal is divided into specified number of segments and for each one, one bit of message is embedded. Comparative and experimental studies are performed to evaluate the effectiveness of the proposed methods, where peak signal to noise ratio(PSNR) is used to assess the speech quality. Results of the study suggested that in the direct sequence method, the higher the speech power ratio, the clearer the hidden image in the signal. The result is better speech quality in communication system receivers. In the differential method, the higher number of segments results in a higher PSNR value. The proposed method are implemented and simulated in MATLAB.