A novel fairness-driven approach for heterogeneous gateways' link scheduling in IoT networks

Internet of Things (IoT) in a real world scenario involves collecting data by sensor devices and communicating the sensed data, through gateway devices, to the IoT Cloud (or the Internet) using direct or multi-hop communication. A gateway typically supports multiple wireless sensor networks (WSNs) and each WSN might use a different technology for communication. Hence gateways are designed to be heterogeneous, having necessary hardware support only for those technologies corresponding to their associated WSNs. Due to their heterogeneity, the technology specific channel access mechanisms need not provide fairness in data communication at each gateway. In this paper, we propose two centralized techniques that involve an efficient link selection per technology and time based scheduling among gateways. This improves fairness in data transmission for every gateway, resulting in an increased data transmission. The first technique uses a multinomial probability based link selection thereby reducing contention within each technology link for a given network topology. The second technique incorporates adaptation to the changing traffic patterns in the network. Our extensive simulation results show that the proposed techniques outperform default technology specific channel access mechanism in IoT networks in terms of total data transmitted, packet delivery ratio, and fairness.