With the increase in emerging bandwidth-intensive applications, millimeter-wave (mmWave) communications in 60-GHz band have become a hot topic. There are two unique features that sharply distinguish mmWave wireless personal area networks (WPANs) from other networks using lower carrier frequencies. First, mmWave links use high-gain directional antennas to overcome the high propagation loss. Second, mmWave links are easily blocked by the human body and furniture. In this paper, we develop a blockage robust and efficient directional medium access control (MAC) protocol (BRDMAC), which overcomes the blockage problem by relaying.
Relay selection and spatial reuse are jointly optimized to improve network performance. In BRDMAC, relay selection and transmission scheduling algorithms are proposed to compute near-optimal relay selection to maximize spatial reuse and compute near-optimal schedules with respect to the total transmission time, respectively. Finally, extensive simulation results show that BRDMAC performs better in terms of delay and throughput, compared with other existing protocols while attaining a good fairness performance.