Synergistic Spectrum Sharing in 5G HetNets: A Harmonized SDN-Enabled Approach

Given the anticipated 1000 times growth of tele-traffic, the conception of efficient spectrum management and sharing mechanisms becomes essential for 5G networks due to the scarcity of spectral resources. To meet this ambitious goal, we propose an SDN-based synergistic spectrum sharing technique, the harmonized SDN-enabled approach (HSA), which relies on distributed input reporting on spectrum availabilities in 5G heterogeneous networks. Conventional spectrum sharing mechanisms, particularly those using cognitive radio techniques, rely heavily on spectrum sensing and adaptive transmission-aided communications devices. However, this device-level spectrum sharing might lead to inaccurate sharing decisions due to the widely fluctuating signal quality observed by each device. Moreover, the network becomes vulnerable to malicious devices that report false sensing data to gain unfair access to the spectrum. These problems are further compounded by the fact that operational cellular networks have a somewhat rigid architecture relying on vendor-specific configuration interfaces, hence restricting the operators to have, at best, only indirect control of the network's operation and resources. In addressing these challenges, we adopt a synergistic approach that integrates the distributed sensing devices, cellular base stations, and SDN controller into an intrinsically amalgamated network. To alleviate any potential controller scalability and latency concerns, HSA harmonizes the network's operation by distributing the local decision making and network-wide policy making tasks among the base stations and the SDN controller, respectively. The article outlines the detailed network architecture and also presents an efficient resource management algorithm.