# A Smart Collaborative Routing Protocol for Reliable Data Diffusion in IoT Scenarios
## 2 Related Work
### Routing Protocols Based on Data  
For the routing protocols based on data, the data fusion issues are taken into account. The cooperation of nodes is used for improving transmission efficiency and saving network energy. [PERSON] et al. [36] presented a novel energy-aware routing protocol named Reliable and Energy Efficient Protocol (REEP) to form a more reliable and energy-efficient path. The REEP protocol consisted of five elements, i.e., sense event, information event, request event, energy event, threshold value and request priority queue. The authors introduced the advantages of REEP in detail, which included sensing event propagation, information event propagation and request event propagation. The paper [37] introduced a modified SPIN (Sensor Protocol for Information via Negotiation) protocol, i.e., M-SPIN protocol to achieve the energy-saving data dissemination. A new phase named \"distance discovery\" was added into the SPIN protocol to identify the distances from nodes to the sink nodes. The results revealed that the proposed protocol lowered the energy consumption and prolonged the network life-cycle. [PERSON] et al. [38] proposed a new secure routing protocol based on the recognizable direct diffusion algorithm, which could resist the black hole and acknowledgement-spoofing attacks. The uTESLA (micro Timed, Efficient, Streaming, and Loss tolerant Authentication) algorithm was used for authenticating the acknowledgement messages from the sink nodes to the source nodes. Finally, the proposed protocol achieved better event-delivery and event-dropping ratio. [PERSON] and [PERSON] [39] presented a Sector Based Clustering Routing (SBCR) protocol for the distributed Data-Centric Storage (DCS). Based on the network-wide cluster flow distribution, each sector was assigned a non-overlapping TDMA slot. Moreover, an optimally synchronized routing algorithm was also introduced to reduce updating and querying traffic, end-to-end delay and collisions. Then a cross-layer optimization model was established in the medium access control layer. In [40], the authors studied three routing protocols in WSN, i.e., location-based routing protocols, data-centric routing protocols and hierarchical routing protocols. For the data-centric protocols, the paper introduced the SPIN and Direct Diffusion protocols. The comparison results were listed based on various parameters (scalability, mobility, power required, energy efficiency, and so on). A reliable SPIN protocol was presented by utilizing the selective forwarding to increase the data delivery radio in [41]. When some packets were unacknowledged by the source node, the source node would forward them again. The results showed that the proposed protocol optimized the Packet Delivery Ratio (PDR), throughput and routing overhead. [PERSON] et al. [42] proposed a modified SPIN protocol to save energy and prolong the network life-cycle. An optimal secure transmission path was selected by efficiently implementing this protocol. The general processes of the proposed protocol included data negotiation, setting up route and transmitting data to nodes. Finally, the routing overhead was reduced and data delivery was guaranteed. [PERSON] and [PERSON] [43] comprehensively analyzed the two prominent data-centric protocols, i.e., DDIFF and SPIN protocols. By using NS2 simulator, NAM (Network Animator), TCL (Tool Command Language) and AWK (post processing script) respectively, the performances of them were given based on the end-to-end delay, throughput, control overhead and PDR. Finally, the DDIFF protocol performed better than the SPIN protocol under the static and mobile environments. [PERSON] et al. [44] presented an energy-efficient SPIN protocol based on the Hybrid Multi Hop Clustering Scheme (SHMCS), which combined EEHMCS and SPIN protocols. Each node of EEHMCS could sense data from the surroundings and send it to its corresponding CH node. By building an energy consumption model, the total energy loss could be calculated.