Iris: A Directional MAC Protocol With Applications to Millimeter-Wave Mobile Ad-Hoc Networks

The scarcity of spectrum in sub-6 GHz frequency bands to meet projected wireless traffic demands has led to the wireless industry incorporating millimeter-wave technology in the design of next-generation wireless systems. The high path loss of millimeter-wave signals necessitates radios that operate in these frequencies to employ highly directional beams for transmission and reception. The transition from traditional omni-directional transmission and reception to highly directional links has drastic implications on the Medium Access Control (MAC) design, since it shifts the objective of the MAC layer from proactive interference avoidance to transmitter-receiver coordination to achieve beam alignment. In this paper, we present IRIS, a directional MAC protocol for mm-wave ad-hoc mobile networks that achieves this objective. Specifically, the Iris protocol is designed to distributedly coordinate the nodes so that transmitters and their intended receivers align their antenna boresights to establish a physical link between them when required. We establish certain performance guarantees that the Iris protocol provides, and illustrate the design process of a mm-wave ad-hoc MAC based on the Iris protocol.