Performance Study of Space Time Coded Mc Cdma Systems

Abstract

Nowadays millions of people are using cellular services in the entire world and newlinethe demand is increasing exponentially. There is also a demand for integration of a newlinevariety of multimedia services such as short messaging, voice, data, and video. newlineConsequently, the bit rate is required to vary from 1.2 Kbps for paging to several Mbps newlinefor video transmission. The data rate of the second generation is limited up to 9.6 Kbps. newlineThe third generation cellular systems are being designed to support wideband newlineservices like high-speed internet access, video, and high quality images transmission newlinewith the same quality as the fixed networks. The third generation can provide the newlinemaximum data rate ranging from 64 Kbps for mobile users to 2 Mbps for stationary newlineusers. The drawbacks arising in the third generation system are the limitations of data newlinerate, capacity, inter symbol interference (ISI), and inter chip interference (ICI). newlineFor solving these problems of wireless communication systems, and fulfilling newlinethe demand of high data rate including broadband internet access with high spectrum newlineefficiency, a multi-carrier code-division multiple-access (MC-CDMA) technology in newlinecombination with multi-input multi-output (MIMO) antennas is considered as one of newlinethe technique in the future generation of wireless communication systems. In the future newlinegeneration communication systems the data rate may be as high as 1 Gbps. newlineOrthogonal frequency division multiplexing (OFDM) is also a popular DFTbased newlinetechnique and its main use is in providing bandwidth reduction as an alternative newlineto conventional multicarrier techniques such as FDM. OFDM has gained popularity newlineii newlinewith the emergence of wireless communications and wideband systems because of its newlineinherent ability to compensate for multipath. In 1993 Linnartz et al. combined OFDM newlinewith code-division multiplexing (CDM) and proposed a new modulation scheme, MCCDMA. newlineMC-CDMA effectively mitigates multipath interference while providing newlinemultiple access capability. newline