**1. Introduction**

Limited medical facility and need for smart digital environments have resulted in exponential usage of WBSN. The WBSN has wide application in areas, including sports, defence, medical, smart home automation, and Internet of Things (IoT) applications. The WBSN provides mobility to patients and avoids the feeling of being monitored. However, the WBSN should also provide prodigious care like being in the hospital during critical situations [1–7]. These tiny, embedded machines are power starving and energy issue is met through battery sources. In WBSN, the sensor node monitors the physiological signals of the human body and transmits the signal to the central node, called central monitoring unit (CMU), which is connected to doctors and other health workers. The CMU is superior in computing and energy capability when compared to other nodes. The data from the nodes are communicated 24 × 7 to ensure the medical safety of the seniors and postsurgical patients [8–11]. Engaging full-time monitoring by a node having limited energy

**Citation:** Arumugam, S.K.; Mohammed, A.S.; Nagarajan, K.; Ramasubramanian, K.; Goyal, S.B.; Verma, C.; Mihaltan, T.C.; Safirescu, C.O. A Novel Energy Efficient Threshold Based Algorithm for Wireless Body Sensor Network. *Energies* **2022**, *15*, 6095. https:// doi.org/10.3390/en15166095

Academic Editor: Alberto Geri

Received: 29 June 2022 Accepted: 18 August 2022 Published: 22 August 2022

**Publisher's Note:** MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affiliations.

**Copyright:** © 2022 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https:// creativecommons.org/licenses/by/ 4.0/).

supply makes nodes unavailable. In some cases, the sensor nodes are implanted inside the human body to monitor the signals deep inside the subject [12–17]. The overloading and continuous monitoring of the signal from implanted node heats the node and causes tissue damage to the subject [10]. The data from each sensor node are communicated to the sink either by star or mesh topology. Figure 1 depicts the STAR topology and MESH topology of the WBSN.

**Figure 1.** Wireless Body Sensor Network topology.

The star topology follows single hop communication and Mesh topology proceeds with multi hop communication. The cluster head (CH) selection or next hop selection mainly determines the lifetime of the network [18–22]. Table 1 illustrates the data rate and different physiological sensor comparison [3,4,10].


