A decomposition principle for link and relay selection in dual-hop 60 GHz networks

We investigate the scheduling problem in a centralized dual-hop 60 GHz network with multiple Source-Destination (SD) pairs, relays, and a PicoNet Coordinator (PNC). The objective is to minimize the Maximum Expected Delivery Time (MEDT) among all SD pairs by jointly optimizing relay and link selection, while exploiting reflected mmWave transmissions and considering link blockage dynamics. We develop a Decomposition Principle to transform this problem into two sub-problems, one for link selection and the other for relay assignment when there is enough replays. We prove that the proposed scheme can achieve an optimality gap of just 1 time slot at greatly reduced complexity. We also develop a heuristic scheme to handle the case when there is no enough relays. The proposed schemes are validated with simulations, where their superior performance is observed.