Higher Spectral Efficiency for mmWave MIMO: Enabling Techniques and Precoder Designs

Millimeter wave (mmWave) communications can support huge data rate growth and wide bandwidth in the new 5G era, and a hybrid precoding architecture can effectively handle the high hardware cost and energy consumption problems. A crucial goal is to optimize the system's spectral efficiency (SE) by effectively designing the digital precoder and the analog precoder. In this article, we review the conventional hybrid precoding schemes in mmWave systems, and then investigate several novel systems with index modulation (IM) techniques as well as their hybrid precoder designs. With the advantages of IM, higher SE can be achieved with limited radio frequency chains in mmWave systems. Simulation results demonstrate that two types of IM-aided systems both outperform conventional mmWave systems, which proves that IM is an enabling technique in practical SE-driven mmWave systems. Finally, we discuss the limiting factors and outlook of IM-aided mmWave systems in beyond-5G wireless communications.

Automated summary

In the new 5G era, millimeter wave communications can achieve huge data rate growth and wide bandwidth with a hybrid precoding architecture, effectively optimizing the system's spectral efficiency through the design of digital and analog precoders. The use of index modulation (IM) techniques can further improve spectral efficiency in mmWave systems. Simulation results demonstrate that IM-aided systems outperform traditional mmWave systems, making IM a promising technique for practical SE-driven mmWave systems.