> REPLACE THIS LINE WITH YOUR PAPER IDENTIFICATION NUMBER (DOUBLE-CLICK HERE TO EDIT) < 1 Abstract—Wireless Body Area Networks (WBANs) provide promising applications in healthcare monitoring of dairy cows. The characterization of the path loss between on-body nodes constitutes an important step in the deployment of a WBAN. In this paper, the path loss between nodes placed on the body of a dairy cow is determined at 2.45 GHz. FDTD simulations with two half-wavelength dipoles placed 20 mm above a cow model were performed using a 3-D electromagnetic solver. Measurements were conducted on a real cow to validate the simulation results. The obtained path loss values as a function of the transmitter- receiver separation are well fitted by a lognormal path loss model and excellent agreement between measurements and simulations is achieved. As an application, the packet error rate and the energy efficiency of different WBAN topologies for dairy cows (i.e., single- hop, multi-hop, and cooperative networks) are investigated. The analysis results reveal that exploiting multi-hop and cooperative communication schemes improve the energy efficiency and increases the optimal payload packet size. Index Terms—Cross-layer performance, dairy cow, energy efficiency, incremental cooperative relaying, multi-hop, on-body propagation, packet error rate, path loss, single-hop, wireless body area network (WBAN). I. INTRODUCTION ITH the advances in wireless communication and micro- electro-mechanical systems (MEMS) [1], computing devices have become smaller, cheaper, combined with an increased functionality and a higher energy efficiency. This situation allows the establishment of Wireless Body Area Networks (WBANs). IEEE 802.15 Task Group 6 describes a WBAN as: “low power devices operating in or around the human body (but not limited to humans) to serve a variety of applications including medical, consumer electronics /personal entertainment and other” [2]. WBANs are finding various applications in areas of medicine, agriculture, sports and multimedia [3], [4]. In [5], a review of the application of WBANs for human health monitoring is presented. By adopting this technology, doctors can remotely check the health status of the patients and they can recommend the suitable medications. For example, prearrangement measurements can be taken to control many diseases such as high blood pressure, heart attack, diabetes, and cancer. WBANs can be effectively used in health tracking of dairy cows to enhance milk productivity and cow welfare. Also, they can be used for detecting diseases such as lameness, which is considered as a major health problem for the dairy farming [6]. When cows are equipped with a WBAN, the farmer manager can analyze multiple health parameters (e.g., temperature from udder or ear) and activity information (e.g., movement from legs, position) in real-time. Therefore, an automatic assessment about the cow’s health can be made using a combination of these parameters. Extensive studies on modelling of on-body propagation loss for humans were already published [7]–[11]. However, till date, the characterization of such propagation channel for dairy cows has not been conducted. Thus, this work is the first to propose proper and efficient path loss models for the on-body channel modelling, which helps to design and analyze the performance of on-body sensor networks for dairy cows. The goal of this work is to develop empirical on-body path loss models for dairy cows at 2.45 GHz, using both simulations and experiments. We also design an energy efficient WBAN for dairy cows. The characterization of the propagation channel is necessary for an efficient communication between the sensors placed at different parts of the cow’s body. The 2.45 GHz band is selected because it is freely available and most practical existing technologies for WBANs work in this band. We Characterization of the On-Body Path Loss at 2.45 GHz and Energy Efficient WBAN design for Dairy Cows Said Benaissa, Member, IEEE, David Plets, Emmeric Tanghe, Member, IEEE, Günter Vermeeren, Luc Martens, Member, IEEE, Bart Sonck, Frank André Maurice Tuyttens, Jeroen Hoebeke, Nobby Stevens, Member, IEEE, and Wout Joseph, Senior Member, IEEE W S. Benaissa, D. Plets, E. Tanghe, G. Vermeeren, L. Martens, J. Hoebeke, and W. Joseph are with the Department of Information Technology, Ghent University/iMinds, Gaston Crommenlaan 8 Box 201, B-9050 Ghent, Belgium (e-mail: wout.joseph@intec.UGent.be). S. Benaissa, B. Sonck, and F.A.M. Tuyttens are with the Institute for Agricultural and Fisheries Research (ILVO)-Animal Sciences Unit, Scheldeweg 68, 9090 Melle, Belgium (email: frank.tuyttens@ilvo.vlaanderen.be). N. Stevens is with DraMCo research group, ESAT, Faculty of Engineering Technology, KU Leuven, Gebroeders De Smetstraat 1, 9000 Ghent, Belgium (email: nobby.stevens@kuleuven.be).