# Opportunistically Exploiting Internet of Things for Wireless Sensor Network Routing in Smart Cities
## 2 Related Work  
Our work is related to routing and data aggregation in the context of IoTs and Smart City. Right from the beginning of WSN in 1970's, routing in WSN has always been one of the main concern. There are a large number of techniques proposed for energy efficient routing and data aggregation. These include routing with heterogeneous sensor nodes, cross network protocols and platforms, and routing with mobile sinks. A few recent surveys by [PERSON] et al. [21], [PERSON] et al. [22], and [PERSON] et al. [13], can be referred for details. An interesting research related to our work, is to use few high power long range devices in a network of short ranged sensor nodes. For instance, [PERSON] et al. [23], demonstrates that the network life time and delivery ratio can be increased by using few long range sensors. With the advent of IoT and Smart City, the routing protocols are revisited. Most of the routing and data aggregation schemes in IoT can be categorized in to two kinds. One is related to the IoT applications only, where the research discusses IoT application requirements and suggests adjustments or compatibility of a protocol in the new application domain. For instance, [PERSON] et al. [24] present an improvement of AODV (Ad hoc On-demand Distance Vector) routing protocol [25] for the IoT applications that considers QoS (Quality of Service), reliability, and energy efficiency. [PERSON] et al. [26] also enhances AODV protocol using a probabilistic approach for increasing the network lifetime and reducing consumed energy. There are works that focus on specific WSN types, such as wireless multimedia sensor networks [27]. Figure 1: A motivational scenario of road infrastructure in Dubai city. The blue star in the middle is the Sink location. Different roads have red, gray, blue, pink color where sensors are deployed. In contrast, the second kind of research, which is more related to our work, uses multiple types of machines with heterogeneous capabilities to communicate and aggregate data. This requires substantial support by middle-ware frameworks and platforms to cope with heterogeneity of devices. For instance, [PERSON] et al. [7] illustrate the design of a large scale IoT test bed and discuss the use of hierarchical architecture for routing data. Similarly, [PERSON] et al. [6], present technologies, protocols, and architecture for Smart Cities and suggest guidelines adapted in Padova Smart City project. A rather different approach is used by [PERSON] et al. [28], wherein a priced public sensing framework is proposed for public data delivery gathered from cloud and heterogeneous resources. The work is data centric, focused on supply and demand chain of public data from mobile phones. [PERSON] et al. [29] introduce data collection in cellular devices using device to device communications in an IoT and Smart City setting. This results in more efficient resource utilization and minimizes energy consumption. They use one device that aggregates data from several surrounding devices and then sends the data to cellular station, instead of each device sending data individually. Very recently, an overview of using traditional WSN protocols for achieving device to device communication in IoT has been presented by [PERSON] et al. [30]. Our work is different from existing works since it considers a static WSN, deployed in a Smart City. Mobile IoT devices owned by public or private owners are external to this deployed WSN. This is a typical scenario for technological evolution in a city, where every device may get connected yet some internal systems may remain individually working. Thus, as explained later, we exploit the presence of these IoT devices. They are used by our platform for the benefit of both WSN and IoT devices. In our IT Platform, we can use any routing protocol that is suitable to the domain of WSN applications. We use AODV routing protocol [25], which is a well accepted and a well studied protocol for WSN [21].