Joint Base Station and Reflector Placement in an urban mmWave Network

Millimeter-wave (mmWave) technology is expected to be the backbone of future communication networks. However, for all its benefits, mmWave communication comes with its fair share of challenges. In this context, the obstacle free strict line-of-sight (LOS) requirement is one of the primary hurdles that has to be crossed. One way to deal with this problem is to densely deploy small range base stations, called gNBs, to overcome outage due to obstacles. Reflectors have been proposed to augment the transmission environment, and reflect mmWaves bypassing the obstacles. Evidently, they can be used to increase the coverage area that do not have LOS with the available gNBs. We argue that considering the placement of gNBs and reflectors independently may lead to suboptimal solution. In this paper, we consider an urban deployment scenario, and attempt to maximally cover it by jointly placing the gNBs and reflectors. Given the hardness of the joint problem, we first develop a set cover based greedy solution and also provide a linear programming (LP) relaxation based solution. With extensive simulations, we show that with fixed number of available gNBs and reflectors to be placed, both our joint placement solutions can achieve a larger coverage compared to an existing approach.