Toward Robust Relay Placement in 60 GHz mmWave Wireless Personal Area Networks with Directional Antenna

Multimedia streaming applications with stringent QoS requirements in 60 GHz mmWave wireless personal area networks (WPANs) demand high rate and low latency data transfer as well as little service disruption. In this paper, we consider the problem of robust relay placement in 60 GHz WPANs with directional antenna. Relays forward traffic from transmitter devices to receiver devices facilitating i) the primary communication path for non-line-of-sight (NLOS) transceiver pairs, and ii) secondary (backup) communication path for line-of-sight (LOS) or NLOS transceiver pairs. By incorporating a classic directional antenna model and characterizing the link contention, we formulate the robust minimum relay placement problem and the robust maximum utility relay placement problem with the objective to minimize the number of relays deployed and maximize the network utility, respectively. Efficient algorithms are developed to solve both problems and have been shown to incur less service disruption in presence of moving subjects that may block the LOS paths in the environment.