Joint optimization of path selection and link scheduling for Millimeter Wave transport networks

In future mobile networks, the wireless transport networks are expected to carry traffic flows with different throughput and delay requirements due to the introduction of Cloud-RAN (C-RAN) and different functional splits that can be used, e.g., as defined by Next Generation Fronthaul Interface (NGFI). A promising wireless technology to support the high throughput requirements of C-RAN splits is Millimeter Wave (mmWave) band technologies standardized by IEEE 802.11ad amendment. Our target here is to derive the mathematical formulation of the path selection and link scheduling problem for mmWave transport networks, where the backhaul and fronthaul flows will co-exist, by defining the constraints brought by different functional splits and the IEEE 802.11ad standard. We present two objective functions that can be used for this problem: load balancing and minimization of the use of air time. We implemented the derived formulations in an Mixed-Integer Linear Programming (MILP) solver and evaluated realistic scenarios of wireless fronthaul/backhaul networks assessing the splits defined by NGFI for LTE.