Multiuser communications for next generation wireless networks

Abstract

Orthogonal frequency division multiplexing (OFDM) has been the technology of choice for years in wired and wireless systems. However, it has some drawbacks that limit its use in the fifth generation of wireless communication systems (5G). Apart from interference implications, the large out-of-band emissions of OFDM reduces the potential for utilization of non-contiguous spectrum chunks known as spectrum aggregation. OFDM also has a very high sensitivity to carrier frequency offset (CFO), which can hamper communication in multiuser scenarios such as uplink communications. Accordingly, stringent synchronization is required which imposes a large amount of overhead on the network and can cause some latency issues. These issues are in particular challenging when considering machine-to-machine (M2M) traffic. Bearing in mind that M2M and the Internet-of-Things are of increasing significance in the context of 5G communication systems, these shortcomings are significant.