Multicarrier Modulation in Advanced Wireless Communication Systems

The selection of appropriate multiple access tecnology is the main issue in design and development of beyond 3G (B3G) wireless systems. This article considers Orthogonal Frequency-Division Multiplexing (OFDM) scheme as a key techinque to implement in next-generation mobile systems. The introduction of OFDM multicarrier technique in new hybrid multiple access technologies should provide a solution for problems limiting current mobile systems, such as sensitivity to multipath conditions, poor bandwidth efficiency, interference and capacity issues, high signal processing complexity and inadequate performance of high-speed data transmission. The theoretical background, characteristics and practical applications of some of the most important multiple access combinations will be reviewed. Finally, the implementation of OFDM in existing single carrier 3G systems and coexistence will be shortly addressed in conclusion.