**Chung-Wen Hung \*, Hao-Jun Zhang, Wen-Ting Hsu and Yi-Da Zhuang**

Department of Electrical Engineering, National Yunlin University of Science and Technology, 123 University Road, Section 3, Douliou, Yunlin 64002, Taiwan; m10512027@yuntech.edu.tw (H.-J.Z.); m10712051@yuntech.edu.tw (W.-T.H.); b10512118@yuntech.edu.tw (Y.-D.Z.) **\*** Correspondence: wenhung@yuntech.edu.tw

Received: 31 August 2020; Accepted: 10 October 2020; Published: 12 October 2020

**Abstract:** Most Internet of Things (IoT) systems are based on the wireless sensor network (WSN) due to the reduction of the cable layout cost. However, the battery life of nodes is a key issue when the node is powered by a battery. A Low-Power WSN Protocol with ADR and TP Hybrid Control is proposed in this paper to improve battery life significantly. Besides, techniques including the Sub-1GHz star topology network with Time Division Multiple Access (TDMA), adaptive data rate (ADR), and transmission power control (TPC) are also used. The long-term testing results show that the nodes with the proposed algorithm can balance the communication quality and low power consumption simultaneously. The experimental results also show that the power consumption of the node with the algorithm was reduced by 38.46-54.44% compared with the control group. If using AAA battery with 1200 mAh, the node could run approximately 4.2 years with the proposed hybrid control algorithm with an acquisition period of under 5 s.

**Keywords:** adaptive data rate (ADR); transmit power control (TPC); time division multiple access (TDMA); wireless sensor network (WSN); power consumption; Internet of Things (IoT)
