Optical Wireless and Millimeter Waves for 5G Access Networks

Abstract

Growing bandwidth demands are driving the search for increased network capacity leading to the exploration of new wavelength ranges for future communication systems. Therefore, we consider two technologies that offer increased transmission bandwidths by virtue of their high carrier frequencies, namely optical wireless and millimeter-wave transmission. After highlighting the relevant electromagnetic (EM) spectrum region, we briefly describe the applications and properties of each approach coupled with a short history of their development. This is followed by a performance comparison in two possible 5G links: outdoor point-to-point and indoor hotspots. We find that in both cases, there are regions where optical wireless communications (OWC) are better, but others where millimeter waves are to be preferred. Specifically, the former outperforms the latter over distances up to approximately 50 meters outdoors and a 10-meter hotspot radius indoors.

Leveraging Massive MIMO Over mmWave Fronthaul Link for Throughput Maximization in Cloud Radio Access Networks

“…Therefore, it becomes a natural choice to utilize the mmWave band in tandem with the massive MIMO at BBU to satisfy stringent throughput requirements. Another reason for using massive MIMO over the mmWave channel is that the large-scale antenna array can be easily integrated into a much more compact area compared to its microwave counterparts, due to smaller wavelengths [19].…”

“…Despite all the advantages, there are several challenging issues while communicating over the mmWave channel. For example, severe path loss, sensitivity to blockages compared to below 6 GHz frequency bands, channel losses, and cost of the equipment [19]. However, favorable propagation offered by massive MIMO has the potential to effectively address the challenges associated with severe path loss and blockage, thereby facilitating the deployment of mmWave in CRAN.…”