Wireless Body Area Network (WBAN) concept is one of the most promising technologies for healthcare applications. In WBANs, sensor nodes are capable of sensing, gathering the human body signs and sending them to the HUB; the communication between nodes and HUB is called as intra-WBAN communications. Inter-WBAN communication manages all HUBs for communications of various WBANs. WBANs have inherently heterogeneous structures and limited energy sources, and also, installation/configuration network management processes are increasingly quite complex. New approaches are required to implement WBANs in order to overcome these challenges. We propose the Software Defined Networking (SDN) approach aims at constructing a flexible and manageable structure for inter-WBAN communications. Therefore, a new SDN-enabled WBAN architecture with HUBsFlow interface protocol is proposed in this paper. The proposed architecture provides a flexible, manageable, and an energy sensitive structure. Hence, a controller that is a key component for SDN undertakes all management and control processes about network. HUBsFlow interface protocol is utilized on the controller that provides the communications among the controller and HUBs in inter-WBAN communications. All components, protocols, and algorithms of the proposed architecture are developed and simulated using Riverbed Modeler software. Throughput, delay, packet loss ratio, bit error rate, and energy consumption parameters are taken into account for performance evaluation of the proposed architecture. The results show that the proposed architecture outperforms when comparing with traditional WBAN architecture and satisfies IEEE/ISO 11073 service quality requirements.

Introduction

WBAN has a heterogeneous network architecture consisting of many sensor nodes, and each node has different tasks and functions. The sensor nodes collect, process and transmit the data to the HUB. HUB is a central node or coordinator in WBAN that manages several sensor nodes. The data usually can be the vital signs and some environment variables [1,2]. The most significant shortage of WBAN is the complexity of the network management functions resulting from the limited resources and physical environments that they have [3,4]. Various data traffic from heterogeneous sensor nodes are transmitted to the target at different sampling times, so the heterogeneity of the network traffic flow makes the service quality requirements and network management more complex. SDN is a new network approach that has been put forward to ensure that the control and the data planes existing together in the traditional network infrastructure are abstracted from each other. With the SDN approach, the control and the management processes logically converge at a central point, and the network control and the management processes become more flexible and easier [5–۸]. One of the popular topics for solving the network complexity is thought to be the solution of the SDN approach to the WBAN architecture. As a result of the SDN approach, the WBAN architecture (SD-WBAN) in this study allows the entire network to be managed via a controller [9]. By the way, a new energy-sensitive interface protocol (HUBsFlow) is developed with the SDN approach, instead of a distributed protocol that causes too much energy consumption among inter-WBAN communications. The control and the management operations on the HUBs are transferred to the controller and the energy consumption of the HUB is reduced dramatically. In addition, with the help of the controller, the network control, and the management operations are carried out from a central point for providing dynamic, effective and efficient resource allocation.