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Year: 2014 | Volume: 13 | Issue: 12 | Page No.: 2061 - 2064
Padmapriya Praveenkumar, K. Thenmozhi, J.B.B. Rayappan and Rengarajan Amirtharajan
Abstract
We live in an era where hacking and unauthorized access attempts to data are so common. There is a need to secure data before it is transmitted. Addition of overhead bits and modulation techniques decrease the capacity and increase the cost. Both the channel capacity and the cost to set up the communication system have to be optimal. So intimidating is a feature called multiple access used for this purpose. Multiple access also improves capacity by simultaneously transmitting large number of messages. There is very less or no interference between the signals since each of them is polarized orthogonally or encoded using different coding sequences or sent as bursts in different time slots. Particularly Code Division Multiple Access (CDMA) makes it more difficult for the hacker to access the transmitted data. If the message is thrown to all the users only the intended receiver has the same coding sequence to decode it. So, others can’t access the message. Even if the message is detected, use of steganography makes it all the more difficult for the hacker to decode the message. This increases the security multifold. The aesthetic appeal of CDMA and steganography together has revolutionized the present world communication systems. In this study, the performance of CDMA is analysed by embedding confidential information at three levels namely after interleaving, spreading and modulator. The Bit Error Rate (BER) performance comparison graphs with and without information hiding at three levels are analysed using BPSK, QPSK and QAM schemes.