Generation of orthogonal logistic map sequences for faded channels in spread spectrum modulation

Spread spectrum system are techniques by which signals are spreaded in the frequency domain and plays a very important role in wireless communication system. For secure communication, chaotic spreading sequence is advantageous but most of them are non-orthogonal. This paper presents the design of an orthogonal chaotic spreading sequence for application in Direct Sequence Spread Spectrum (DS SS) system for faded wireless channels. Enhancing the quality of service (QOS) and security of data transmission are prime issues which can better be addressed with chaotic sequences. In this paper, generation and application of orthogonal chaotic sequence is done and a comparison with non orthogonal chaotic sequence is presented. Also the generated orthogonal spreading sequence is applied for DS SS system using different channels and the results are compared. The comparison factors are bit error rate (BER), mutual information, signal power and computational time, which finally states the efficiency of generated code. Again a multiplier-less chaotic sequence generator is proposed for lower power requirement than the existing one.