Design and development of code division multiple access techniques for various communications and signal processing applications

Abstract

The goal for the next generation of mobile communication systems is to seamlessly integratewide variety of communication services such as high speed data, video and multimediatraffic as well as voice signals and high data rates with low bandwidth.Further, communication systems are to be power efficient.The technology needed to tackle these challenges to make theseservices available is popularly known as Code Division Multiple Access technology which is being employed in Third Generation (3G) and Fourth Generation 4G communication systems. One ofthe most promising approaches to 3G and 4G systemsis to combine a Wideband Code Division MultipleAccess (WCDMA) air interface with the fixed network of Global System for Mobilecommunications also called as Group Service Mobile (GSM). The work carried out in this thesis is concerned with the design and development of Code Division Multiple Access techniques for various Communications and Signal processing applications. The statistical properties of Pseudo- Noise (PN) codes have also been thoroughly studied. Chaotic signals have been generated using novel techniques. The main focus has been given on Multi- carrier and Multiuser CDMA communication systems. In a practical CDMA communication systems the transmitted signal is corrupted bymultiple access interference which is generated in a structured way rather than treating it asAdditive White Gaussian Noise (AWGN). The signal is further corrupted by AWGN at thefront end of the receiver; various techniques have been proposed in this thesis which exploits the characteristic properties of frequency selective channel like Rayleigh channel. The modeling of frequency selective channel has also been done. Beam forming and rake diversity combing has beenemployed.The bit error rate, correlation and power spectral density properties have been investigated atthe receiving end to evolve the performance of the proposed techniques.