# Reliable Fault Tolerant-Based Multipath Routing Model for Industrial Wireless Control Systems
## 2 Literature Review  
### Fault Tolerance and Multipath Transmission Technologies  
The wireless network that adopts the technology of multipath transmission associated with fault tolerance has the purpose of transmitting the data packets through multiple routes created between the source and destination nodes. It reassembles a specific number of encrypted packets delivered at the sink node into the original packets at the source node. The approach of redundant routing and network encoding is used to increase both load balancing and transmission capacity, resulting in improved fault tolerance and data transmission reliability, as well as improved performance. Multipath routing technologies including geographical routing, QoS based routing, and energy-aware routing have been proposed by numerous researchers [27]. An algorithm called kautz-based real-time, fault-tolerant, and energy-efficient (REFER) was proposed for the development of an efficient fault-tolerant routing protocol that identifies the multiple shortest paths from the source node to the sink node and performs multicasting between and within the cells of the Kautz graph [28]. Authors in [29] proposed a distributed width-controllable braided multipath routing (WC-BMR) based on local neighbor data for the purpose of collecting data in wireless sensor networks. Similarly, authors in [30] proposed a multipath prefix routing (MPR), which is based on multipath routing protocol in a wireless sensors network. Geographic routing systems such as GEAM (Geographic Energy-Aware non-interfering Multipath), DGR (Directional Geographical Routing) and GPSR (Greedy Perimeter State Routing) are assessed and analyzed as efficient routing techniques [20]. Multipath routing may, however, require some optimization when it is subjected to multiple function issues in the presence of certain conditional variable constraints. The algorithm is enhanced with other measures for evaluating the network's performance, such as routing stability, energy consumption, network delay, and packet delivery ratio. In particular, the huge number of sensor nodes deployment and meanwhile the existence of faulty nodes in the dynamic topology network has become a key issue in how to enhance the convergence and optimization performance. On the other hand, the definition of fault tolerance is simply the ability to determine various types of unusual conditions in a specific time and to devise a suitable fault-tolerant control method to instantaneously handle various network abnormalities while continuing to sustain network reliability and stability. Reliable transmission is a crucial measure for evaluating the performance of the transmission, which is primarily indicated by the error rate of packets and the successful packet transmission rate. Multipath routing, in wireless sensor networks, is essentially a redundant routing approach. It serves as a fault tolerance mechanism, preventing effects generated by fault links or nodes. Hence, adopting the strategy of multipath routing into industrial wireless networks is necessary to provide fault tolerance through multipath transmission to enhance the transmission reliability performance. Disjoint path vector (DPV) is a distributed topology-based fault-tolerant control algorithm that was developed to resolve the k-degree any cast topology control issue. It is able to tolerate up to k-1 node failures in worst-case scenario by satisfying the k-vertex super node connectivity and ensuring k-vertex-disjoint pathways to supreme nodes [31]. The adaptive disjoint path vector (ADPV) technique proposed by authors in [32] is used to ensure the connectivity of super nodes in the event of node failures. Fault tolerance and fault detection in the wireless sensor networks are modeled and analyzed in [33]. [PERSON] et al. [34] proposed an efficient technique for the recovery objective that aims to construct inter-partition bi-connected topology while deploying the fewest relay nodes and minimizing the longest path between partition pairs.