# Opportunistically Exploiting Internet of Things for Wireless Sensor Network Routing in Smart Cities
## 1 Introduction
This paper presents an opportunistic use of IoT for better resource utilization of a WSN by building Integration Platform (IT Platform). In our work, we reduce resource utilization by allowing sensors to route few data packets of other sensors to the Sink. Thus, instead of utilizing traditional WSN routing protocols, we opportunistically use IoT devices in the surrounding environment for routing. This enables the Sensor in deployed area to conserve energy [20]. To better understand the problem scenario, let us consider a series of sensors deployed at road side of a Smart City, and there are intelligent cars (as IoT devices) using the road. Figure 1 shows an example scenario in Dubai City where monitoring sensors are deployed at the highway bridge. Our main idea is that instead of sensors routing data to the sink located at the end of the road, IT Platform can be used to let a passing smart car collect the data (on sensor's behalf) and deliver it to the sink. In case a smart car starts moving away from the sink, it will inform a sensor of WSN, which in turn may use another IoT device or may use WSN routing. Usually, IoT devices that are near WSN, are more likely to get re-charged by their own sources. In contrast, the WSN, once deployed, is hardly re-charged. Thus, it is natural to use communication resources of these IoT devices and save energy of sensors in WSN. Since the IoT device owners enable resource sharing and allow IT Platform to be installed, they should receive some reward. Although detailed discussion of this reward is out of scope of this paper, we do state a couple of examples. The reward could be in the form of points, redeemed at a car parking or public charging space. It could also be in the form of giving access to a specific public information portal. We want to emphasize that using our IT Platform, we are making explicit use of IoT devices, considering them as a part of the environment [20] in which WSN is deployed. This is contrary to the traditional research conducted for routing in WSN for IoT, where in most cases an existing protocol is adapted and reused for routing in WSN for IoT applications. Thus, IoT devices are not an integral part of our WSN, rather they are the Smart devices passing by the area where a separately administered WSN is deployed. This makes our approach a novel data collection and routing scheme. The main contribution of this paper is (1) a novel idea with a prototype that uses IoT devices in a pragmatic scenario for conserving energy in a WSN, (2) IT Platform connects an existing WSN with IoT devices that are in the surrounding environment, and (3) evaluation of the prototype from multiple aspects. We describe our problem scenario and illustrate by extensive simulations that demonstrate and evaluate the IT Platform. It is observed that by using IT Platform that opportunistically uses IoT devices, not only WSN energy is conserved but packet reception rate is also improved. The rest of the paper is organized as follows. Section 2 summarizes other research efforts related to our work. In Section 3, problem scenario and requirements are defined. IT Platform is detailed in Section 4. The Castalia simulator, experiment details, and evaluation are discussed in Section 5. Finally, Section 6 concludes the paper.