Load-Aware Sub-Band and Wavelength Allocation in Radio-over-Fiber Enabled Dense Wireless Pico-Cell Networks

The development of 5G wireless networking is flourishing, introducing major paradigm shifts and key new technologies such as Radio- over-Fiber (RoF). A fundamental concept for achieving the 5G design objectives is dynamically allocating frequencies, sub-bands and wavelengths. While these allocation problems have been extensively studied in wireless and optical domains in isolation, the combination has received little attention so far. However, with the advances in software-defined radio access networking and RoF technologies, there is increasing need and scope for joint optimization across the two domains, in order to harness the full potential of these networks. Motivated by these observations, we introduce a model for jointly optimal sub-band and wavelength allocation in pico-cell networks where virtual access points (APs) transmit via remote radio heads (RRHs) connected through RoF technology. We specifically account for the optical network topology, which introduces a distinct set of constraints in both the optical and wireless domain. Since the resulting load balancing problem is NP-hard, we introduce a heuristic for obtaining a stabilizing allocation which provides all RRHs with sufficient spectrum capacity to deal with their load. Numerical experiments demonstrate that the heuristic provides near-optimal solutions.