Comparison of multicarrier CDMA with successive interference cancellation and interference cancellation with gibbs sampler

Abstract

Recently Orthogonal Frequency Division Multiplexing (OFDM) has gained a lot ofattention and is the technology for Fourth Generation (4G) wireless systems because itpromises data rates up to 100 Mbps. A variation of OFDM is Multi-Carrier Code Division Multiple Access (MC-CDMA) which is a combined technique of Direct-Sequence (DS)CDMA and OFDM techniques, which is also an OFDM technique where the individualdata symbols are spread using a spreading code in the frequency domain which resultsmulti carriers. The spreading code associated with MC-CDMA provides multiple access technique as well as interference suppression.In Code Division Multiple Access technologies, all other users different from thedesired user in the system are also interference sources apart from noise. For this reason inCDMA systems the main resource is power. To suppress the interference level in the system and the interference caused by other users, because of the complexity of Multi UserDetection (MUD) technique, much lower complexity than MUD technique which is calledInterference Cancellation methods are used. Mainly there are two interference cancellationmethods used which are Serial (Successive) Interference Cancellation (SIC) and Parallel Interference Cancellation (PIC). Gibbs sampler in interference cancellation gained a lot ofattention which is an interference cancellation between serial and parallel type interferencecancellation also introduce randomness in the interference cancellation scheme.In this thesis, we apply these two interference cancellation techniques which are Successive Interference Cancellation and Interference Cancellation using Gibbs Sampler tothe Multi Carrier CDMA system. We investigate the performance of these two systemswith simulations and have observed better results from IC scheme with Gibbs sampler.