# A Novel Adaptive Cluster Based Routing Protocol for Energy-Harvesting Wireless Sensor Networks
###### Abstract  
With the various applications of the Internet of Things, research into wireless sensor networks (WSNs) has become increasingly important. However, because of their limited energy, the communication abilities of the wireless nodes distributed in the WSN are limited. The main task of WSNs is to collect more data from targets in an energy-efficient way, because the battery replacement of large amounts of nodes is a labor-consuming work. Although the life of WSNs can be prolonged through energy-harvesting (EH) technology, it is necessary to design an energy-efficient routing protocol for the energy harvesting-based wireless sensor networks (EH-WSNs) as the nodes would be unavailable in the energy harvesting phase. A certain number of unavailable nodes would cause a coverage hole, thereby affecting the WSN's monitoring function of the target environment. In this paper, an adaptive hierarchical-clustering-based routing protocol for EH-WSNs (HCEH-UC) is proposed to achieve uninterrupted coverage of the target region through the distributed adjustment of the data transmission. Firstly, a hierarchical-clustering-based routing protocol is proposed to balance the energy consumption of nodes. Then, a distributed alternation of working modes is proposed to adaptively control the number of nodes in the energy-harvesting mode, which could lead to uninterrupted target coverage. The simulation experimental results verify that the proposed HCEH-UC protocol can prolong the maximal lifetime coverage of WSNs compared with the conventional routing protocol and achieve uninterrupted target coverage using energy-harvesting technology. Keywords:wireless sensor network; energy harvesting; hierarchical clustering algorithm; environment adaptive routing protocol; uninterrupted target coverage +
Footnote †: journal:  
_Article_  
A Novel Adaptive Cluster Based Routing Protocol for Energy-Harvesting Wireless Sensor Networks [PERSON], [PERSON], [PERSON], [PERSON], [PERSON], [PERSON], A. A Novel Adaptive Cluster-Based Routing Protocol for Energy-Harvesting Wireless Sensor Networks S. S.  
reception and transmission is the main cause [6]. Therefore, the balance of traffic load is the crucial task to preserve the hotspot nodes from being quickly exhausted [7; 8], thus prolonging the maximum lifetime coverage (MLC) of WSNs. The design of communication protocols can significantly optimize the MLC problem of WSNs. Many research works exist on data transmission schemes used to balance the energy consumption of WSNs and the data compression methods used to reduce the energy required for data transmission [9; 10]. However, data fusion is a comprehensive problem, which contains many problems that remain to be studied. Therefore, the optimization of routing protocols is the main focus of this paper, and will be comprehensively reviewed in this section. The data sensed by the nodes are transmitted to the base station (BS) [11]to complete the monitoring of the target area. For the transmission of data of the same size, the energy consumption obviously increases along the propagation distance, especially for the scenario where the base station is fixed far from the information collection network. Thus, the heavy transmission task may cause a degradation in the perceived quality of the sink nodes and queuing delays due to insufficient bandwidth [12]. A comparison of the conventional routing protocols is depicted in Table 1.  
In [13], a low-energy adaptive clustering hierarchy LEACH) was proposed, the cluster head nodes (CHs) compress the data received from the respective cluster and send an aggregated packet to the BS to reduce the amount of transmission data [14]. In [15], a greedy, chain-based, power-efficient gathering in sensor information systems (PEGASIS) is proposed to optimize the LEACH protocol. The PEGASIS protocol organizes all of the nodes to form a chain, so the data can be fused hierarchically and transmitted to the BS by the leader head node.