A survey of single and multi-hop link schedulers for mmWave wireless systems

Wireless communication at 60 GHz, aka mmWave, provides extremely high data rates, i.e., several Gb/s. Moreover, devices have a much shorter transmission range as compared to those operating in the 2.4 and 5 GHz bands. Indeed, links can be treated as pseudo-wires with minimal interference leakage. As a result, future 60 GHz systems will have very high spatial reuse. This, however, is at the expense of high propagation loss, which can be overcome using directional or smart antennas. Another promising solution is to employ relays to boost the signal of weak links. In particular, if relays are properly selected, they are able to offer higher data rates than direct links, and also help circumvent obstacles. To this end, we review state-of-the-art schedulers that take advantage of the high spatial re-use afforded by 60 GHz wireless systems to activate multiple links within a channel time allocation. Moreover, we survey works that use passive and active relays to overcome obstacles and to facilitate novel applications. We also survey those that maximize both spatial reuse and throughput of both direct and indirect (relay) links simultaneously.