# A Smart Collaborative Routing Protocol for Reliable Data Diffusion in IoT Scenarios
## 1 Introduction  
The rapid evolution of Internet of Things (IoT) promotes the life quality and work efficiency for human [1]. The IoT is a creative pattern of connecting various things, which contains two meanings. First, the core and foundation of the IoT are still the network, which is an extension and expansion of the Internet. Second, the end users are extended to any items for information exchange and communication, i.e., the connection of objects. Due to the sensing function and wireless communication capability, the applications of IoT are providing broad prospects. As a pervasive technology, it has been widely used in vehicle monitoring, health care, urban transportation, space exploration and other promising fields [2]. As the most representative member of IoT, the Wireless Sensor Network (WSN) can serve as a general platform for many domains, such as measurement of various environmental parameters (temperature, pressure, humidity, light, etc.). For the commercial and military applications, secure and reliable communications are crucial for maintaining data dependability and confidentiality [3]. In recent years, many security aspects in WSN have been reconsidered, such as routing, localization, data fusion and access control [4; 5; 6; 7]. We take the secure routing as an example. As the foundation ofthe information perception and transmission in IoT, the selection of routing strategies is an important part for the security defense and efficient delivery [8; 9; 10; 11]. The design process of a routing protocol needs to make tradeoff in complexity, energy consumption and other aspects. An excellent routing protocol should resist the illegal intrusions and malicious destructions without affecting the normal packet exchanging. As an eligible member of security routing protocols, the geographic routing protocols forward the request packets to a specified location by utilizing the location information of nodes, which shortens the scope of data transmission. Two typical schemes are Greedy Perimeter Stateless Routing (GPSR) and Geographic and Energy Aware Routing (GEAR). For the geographic routing protocols, each node can perceive and exchange its own position with the neighbor nodes. Therefore, the forwarding path will be established by referring to the location information. However, the routing protocols in WSN frequently suffer various attacks, including selective forwarding attack, black hole attack, Sybil attack, wormhole attack, hello flooding attack, ACK attack and so on [12; 13]. Among them, the black hole and wormhole attacks are more intractable to be monitored. Although it is effortless for the traditional geographical routing protocols to cope with both attacks, the shared location information of nodes might be intentionally misrepresented or maliciously modified by Sybil attacks. Therefore, a reliable, stable and effective routing protocol is urgently needed in the current WSN. Motivated by above considerations, we aim to focus on the routing and transmission scheme to optimize network performances. First, a novel geographical routing protocol, Geographic energy aware routing and Inspecting Node (GIN), is proposed, which integrates the GEAR protocol with the inspecting mechanism. On the one hand, the GEAR protocol can easily establish the routing path by leveraging the local cooperation information of nodes, rather than requesting them from the base station. According to the geographical information of nodes, the location of so-called \"neighbors\" can be found, which might be further than the spread range of normal signals. Thus, it is quite hard for an attacker to form a sewage pool. Once a wormhole attack is launched to affect traffic, the behaviors will be immediately detected. On the other hand, the new idea of combining with Inspecting Node (IN) can deploy the reputation scheme to restrain the Sybil and selfishness attacks [14]. The inspecting nodes can be selected through the game theory. Finally, the network model is established and the specific simulation results are provided.