# A Load Balancing Routing Mechanism Based on SDWSN in Smart City  
[PERSON] Cui  
1 Institute of Network Technology, Beijing University of Posts and Telecommunications, Beijing 100876, China; [EMAIL_ADDRESS] (X.C. ); cssd@bupt. The problem of load balancing in WSN has been studied by a large number of scholars for a long time. In order to solve the problem of load imbalance in wireless sensor networks, researchers put forward many solutions. In [4], Based on LEACH, an improved LEACH protocol in WSNs is proposed. The LEACH protocol acts as a low-power adaptive hierarchical routing protocol, randomly selecting cluster heads in a cyclical manner to evenly distribute energy consumption in the network. In WSN, sensor nodes depend on each other when forwarding information packets from a source station to a base station by routing algorithm. Some routes may be better than others, which may result in an unbalanced contention for different routes, as one route may be exhausted more often or faster than others. In [5], they analyze this problem from the perspective of game theory and model the path selection problem in WSN as an evolutionary anti-coordination routing game. In order to prolong network lifetime, candidate forwarders should be selected so that load is balanced among nodes. In [6], they proposed an ORR, an opportunistic routing protocol. In [7], they proposed a simple and effective queue utilization based RPL (QU-RPL) that achieves load balancing and significantly improves the end-to-end packet delivery performance compared to the standard RPL. QU-RPL is designed for each node to select its parent node considering the queue utilization of its neighbor nodes as well as their hop distances to an LLN border router (LBR), owing to its load balancing capability. In [8], a framework is proposed for load balanced routing in WSN. In-network path tagging is used to monitor the network traffic load of nodes. Based on this, nodes are identified as being relatively overloaded, balanced or under loaded. A mitigation algorithm finds suitable new parents for switching from overloaded nodes. The routing engine of the child of the overloaded node is then instructed to switch its parent. The above dynamic routing data forwarding mainly relies on the local node information, which easily falls into the local optimum, while the global improved routing algorithm is difficult to distribute and is not suitable for large-scale sensor networks. SDN came into being, control and forwarding separation features provide effective way for WSN routing algorithms. As shown in Figure 1, SDN\(-\)based network architecture will be more flexible, and application upgrades will be more simplified. This paper discusses the WSN architecture based on SDN. For the multi-path optimized SDWSN load balancing problem, a routing scheme based on an Elman neural network for improved solution is proposed. In order to minimize the maximum link utilization in the network, this paper establishes a mathematical model based on multi-path routing technology while satisfying the quality of service, and the model is simulated and verified. The results show that the load balancing strategy can minimize the maximum link utilization in the network, and fully utilize the network link resources to reduce intra-domain delay and extend network lifetime. This paper summarizes and analyzes the SDN technology, and designs the load balancing model of the data plane and control plane in the SDWSN, which provides a new solution for the load balancing problem. Our major contribution can be summarized as follows:  
Figure 1: Software defined network (SDN) overall architecture. The algorithm model combines the hierarchical structure of an Elman neural network with the clustering structure of a wireless sensor network routing protocol, and designs an Elman neural network model in each cluster structure. By designing a neural network algorithm model, a little amount of data information reflecting the characteristics of the original data is obtained.