An SDN-based framework for elastic resource sharing in integrated FDD/TDD LTE-A HetNets

Spectrum and infrastructure sharing among multiple mobile network operators have recently drawn significant attention from the industry and the academia sectors. Recent advances in the area of Software Defined Networking (SDN) launch the design of innovative SDN-based solutions for resource sharing in multi-tier networks of macrocell and small-sized base stations, a.k.a. HetNet. In this paper, we present a novel SDN-based framework that enables efficient and elastic spectrum utilization among multiple operators in 3GPP LTE-A HetNet scenario. Assuming a multi-operator environment of Frequency Division Duplex (FDD) macrocells complemented by multi-tenant Time Division Duplex (TDD) pico cells, we present a SDN-based architecture that allows efficient resource sharing among the TDD and FDD systems in a dynamic way. A TDD frame re-configuration mechanism is also employed, to optimize the ratio of uplink and downlink slots in the TDD frame of picocells. System-level simulation results demonstrate that the combination of these two functional enhancements in the LTE-A HetNet, significantly reduces the application layer delay for both the FDD macrocell and TDD picocell systems, leading to highly efficient and dynamic spectrum sharing among multiple network operators.