  Future mobile traffic growth will require 5G cellular networks to densify the
deployment of small cell base stations (BS). As it is not feasible to form a
backhaul (BH) by wiring all BSs to the core network, directional mmWave links
can be an attractive solution to form BH links, due to their large available
capacity. When small cells are powered on/off or traffic demands change, the BH
may require reconfiguration, leading to topology and traffic routing changes.
Ideally, such reconfiguration should be seamless and should not impact existing
traffic. However, when using highly directional BH antennas which can be
dynamically rotated to form new links, this can become time-consuming,
requiring the coordination of BH interface movements, link establishment and
traffic routing. In this paper, we propose greedy-based heuristic algorithms to
solve the BH reconfiguration problem in real-time. We numerically compare the
proposed algorithms with the optimal solution obtained by solving a mixed
integer linear program (MILP) for smaller instances, and with a sub-optimal
reduced MILP for larger instances. The obtained results indicate that the
greedy-based algorithms achieve good quality solutions with significantly
decreased execution time.
