Design and performance analysis of quasi-asynchronous SC-FDMA-CDMA system using quasi complementary sequence sets

In this paper, we have proposed a modified hybrid technique which is a combination of single carrier frequency division multiple access (SC-FDMA) and multicarrier code division multiple access (MC-CDMA) called as SC-FDMA-CDMA. The system is designed based on quasi complementary sequence set (QCSS) over a quasi-asynchronous environment. SC-FDMA-CDMA provides lower peak to average power ratio than that of MC-CDMA technology. The QCSS code is generated over the complex roots of unity and has a low correlation property which makes SC-FDMA-CDMA suitable over the quasi-asynchronous environment. In addition, QCSS can support more users than that of perfect complementary sequence sets. A complete transceiver structure has been provided in detail. The system performance has been derived from a simulation and analytical studies. It has been observed that quasi-asynchronous SC-FDMA-CDMA based on QCSS performs better than that of Walsh Hadamard or complete complementary codes based quasi-asynchronous SC-FDMA-CDMA.