SDN-Based Smart Gateways (Sm-GWs) for Multi-Operator Small Cell Network Management

Small wireless cells have the potential to overcome bottlenecks in wireless access through the sharing of spectrum resources. However, current backhaul networks statically allocate resources, resulting in minuscule allocations when many small cells are connected to cellular operators with given resources. We introduce a novel access backhaul network architecture based on a smart gateway (Sm-GW) between the small cell base stations, e.g., long term evolution (LTE) enhanced Nodes B (eNBs), and the conventional backhaul gateways, e.g., LTE servicing/packet gateways (S/P-GWs). We specify the modest LTE protocol modifications that integrate the Sm-GW into the conventional LTE network. The Sm-GW flexibly schedules uplink transmissions for the eNBs. Our simulation evaluations indicate that the Sm-GW scheduling can fairly allocate uplink transmission bitrates to the eNBs and reduce packet delays. Based on software defined networking (SDN), we introduce a management mechanism that allows multiple operators, i.e., multiple S/P-GWs, to flexibly inter-operate via multiple Sm-GWs with a multitude of small cells. An SDN orchestrator coordinates the adaptive allocation of uplink transmission bitrates to Sm-GWs (which in turn allocate the uplink transmission bitrates to eNBs based on their demands). We formulate optimization problems for the operator (S/P-GW) resource allocation to Sm-GWs without and with sharing among operators. Our numerical evaluations indicate that the flexible SDN orchestration substantially increases the network throughput compared to the current static resource allocations.