Design Aspects of Short-Range Millimeter-Wave Networks: A MAC Layer Perspective

Increased density of wireless devices, ever growing demands for extremely high data rate, and spectrum scarcity at microwave bands make the millimeter-wave frequencies an important player in future wireless networks. However, millimeter-wave communication systems exhibit severe attenuation, blockage, and deafness, and may need microwave networks for coordination and fall-back support. To compensate for high attenuation, mmWave systems exploit highly directional operation, which in turn substantially reduces the interference footprint. The significant differences between millimeter-wave networks and legacy communication technologies challenge the classical design approaches, especially at the MAC layer, which has received comparatively less attention than PHY and propagation issues in the literature so far. In this article, the MAC layer design aspects of short-range millimeter-wave networks are discussed. In particular, we explain why current mmWave standards fail to fully exploit the potential advantages of short-range mmWave technology, and argue for the necessity of new collision-aware hybrid resource allocation frameworks with on-demand control messages, the advantages of a collision notification message, and the potential of multihop communication to provide reliable mmWave connections.