bstract
The exponential growth of wireless multimedia services and devices expect more spectrums to support the quality of service (QoS) of the fifth-generation (5G) and beyond cellular networks. The available large underutilized radio resources in millimeter wave (mmWave) have the potential to solve limited radio resource issues of the existing cellular bands. Recent studies suggest that densely deployed mmWave base stations with directional beamforming capability can be used for cellular systems. However, the exploitation of mmWave channels for the cellular network also introduces new challenges because of the inconsistent transmission behavior of the mmWave channel. Despite the problems raised for the mmWave signals, there are recent breakthroughs that make the mmWave viable for cellular communications, and the cellular network infrastructure should be expanded accordingly. In this regard, this chapter presents a review of issues associated with the mmWave-based cellular networks. Furthermore, key concepts and useful insights related to the mmWave-based cellular network design are also provided. Besides, a stochastic geometry-based theoretical framework is developed to account for the effect of the exploitation of mmWave for the cognitive-based multi-tier cellular networks. In this scheme, when conventional cellular channels are vacant, low power nodes operate in the traditional cellular band, and they are served by the mmWave band when channels are busy. Outage probability, area spectral efficiency, and energy efficiency are theoretically calculated for the system. Numerical results demonstrate that the proposed approach offers a significant improvement in outage performance as compared to cognitive radio-based multi-tier networks.
