Multi-carrier Transmission Techniques for Wireless Communication Systems: A Survey

The next generation wireless communications systems require higher data rates transmission in order to meet the higher demand of quality services. Research in wireless digital communications techniques have been expending very rapidly in the last few decades, resulting more reliable wireless communication systems that operate at higher spectral efficiency. Since there have been an increased in demand for higher data rate transmission, the systems are incorporating the multi-carrier transmission techniques. Therefore, Orthogonal Frequency Division Multiplexing (OFDM) is one of the leading candidates for future wireless systems. The objective of the paper is to provide a survey on multi-carrier transmission techniques i.e. OFDM and the combination of OFDM with Code Division Multiple Access (CDMA). The review on this rapidly expending area of wireless communication field is carried out on research works for the past 15 years. And in this survey also we Trying to explain how to use Discrete Wavelet Transform based OFDM (DWT-OFDM) Instead of using Fast Fourier Transform based OFDM Fast Fourier Transform based OFDM (FFT-OFDM). This study outlines the state-of-the art of OFDM novel technique as well as the methods of multi-carrier Code Division Multiple Access (MC-CDMA) and MCDirect Sequence-CDMA (MC-DS-CDMA). Key-Words: Multi-carrier-CDMA (MC-CDMA), Multi-carrier Direct Sequence-CDMA (MC-DS-CDMA).