Energy-Efficiency in Cache-Enabled mmWave Cellular Networks

Millimeter wave (mmWave) is a promising radio wave technique for the fifth generation communication systems (5G) due to its wider frequency bands than that of the conventional microwave. mmWave single-input single-output(SISO) transmission technology is subject to high path loss and low energy efficiency caused by the high spectrum frequency of mmWave. As an alternative, massive multiple input multiple output (mMIMO) transmission schemes have been proposed to compensate for the high path loss via multiple antenna array system. In this paper, we consider the cache-enabled mmWave cellular networks using mMIMO and explore the energy-efficient scheme for it by proposing a non-linear programming (NLP) model. The objective of the proposed model is to minimize the power consumption of cache-enabled mmWave cellular networks while maximizing the successfully served user requests from mobile stations (MSs). The evaluation on the proposed model is conducted in twofold. First, we investigate the propagation characteristics of point-to-point (P2P) mmWave links using frequencies of 28GHz, 39GHz, and 73GHz, respectively, and the gain provided by mMIMO in terms of their path loss and energy efficiency. Second, we consider six network scenarios differing in the spectrum frequency and whether mMIMO is employed. The numerical analyses of these scenarios in terms of energy efficiency are investigated and compared.