Efficient Gateways Placement for Internet of Things with QoS Constraints

In the Internet of Things (IoT) era, a large number of data packets are exchanged among devices over the Internet. IoT (smart) end devices forward their traffic to the Internet, either by direct communication to LTE networks, or by multi-hop transmissions to a specific gateway. Acquiring both types of communication capabilities would be unnecessarily costly for IoT end devices. Instead, to lower the overall cost, only devices performing as gateways could be fully equipped with such capabilities, while the rest of the devices could have simple low cost wireless transmitters for forwarding the traffic towards a gateway. Towards this end, the decision on gateway placement is critical to provide low cost and Quality of Service (QoS). To address this design problem, we present an Integer Linear Programming (ILP) that minimizes the total cost of the network with respect to the deployed devices, while achieving mandatory QoS requirements. Using this formulation we obtain solutions for random topologies that exhibit the effectiveness of our approach in terms of network cost and efficiency.