Scalable two-hop relaying for mmWave networks.

The performance of millimeter wave (mmWave) networks is limited by severe blocking effects. Mobile relaying exploiting possible two-hop line-of-sight connections is a strong candidate for coverage extension and consistent user experience in mmWave networks. Here, relaying based on opportunistic analog beamforming is investigated, and sets of fixed beams are used for cell discovery, relay discovery and data transmission. A low-complexity relay & beam discovery and selection protocol is considered. Communication performance and signaling overhead are estimated. To provide good relaying performance for cell-edge users without introducing high relaying overhead, a relay candidate set is selected by choosing a proper size, and suitable membership based on a utility function. Simulation results show that with relay candidate sets having a proper size, opportunistic two-hop mmWave relaying can achieve both high mean user performance and consistent user experience.