Indonesian Journal of Electrical Engineering and Computer Science Vol. 22, No. 3, June 2021, pp. 1505~1512 ISSN: 2502-4752, DOI: 10.11591/ijeecs.v22.i3.pp1505-1512  1505 Journal homepage: http://ijeecs.iaescore.com Energy consumption study of channel access modes and modulation schemes of the 2.4 GHz narrowband IEEE 802.15.6 Marwa Boumaiz 1 , Mohammed El Ghazi 2 , Mohammed Fattah 3 , Anas Bouayad 4 , Moulhime El Bekkali 5 1,2,4,5 Laboratory of Artificial Intelligence, Data Sciences and Emerging Systems, Sidi Mohamed Ben Abdellah University, Fez, Morocco 3 IMAGE Laboratory, Moulay Ismail University, Meknes, Morocco Article Info ABSTRACT Article history: Received Feb 18, 2020 Revised Jun 2, 2021 Accepted Jun 13, 2021 Energy efficiency is an important challenge for wireless body area networks. Therefore, choosing the channel access modes and modulation schemes that guarantee lower energy consumption is necessary to increase the network lifetime, especially in wireless body area network (WBAN) medical applications. The purpose of this paper is to analyze the network energy consumption in on-body medical applications (which are classified as low data rate, medium data rate, and high data rate applications) for two channel access mechanisms: random and scheduled access modes, and two modulation schemes: differential quadrature phase shift keying (DQPSK) and differential binary phase shift keying (DBPSK), which are supported by the 2.4 GHz band of the Institute of Electrical and Electronics Engineers (IEEE) 802.15.6 standard. The considered on-body area network (BAN) of the study supports two communication scenarios: the line-of-sight transmission and the non-line-of-sight communications, referenced as CM3A and CM3B path loss models respectively. Simulation results have demonstrated that the scheduled access mode based on time-division multiple access (TDMA), and DQPSK are the optimal choices to be made at the media access control (MAC) and physical layer levels respectively, in terms of energy efficiency, in low, medium, and high data rate on-body WBAN applications. Keywords: 2.4 GHz modulations Energy efficiency IEEE 802.15.6 Random access Scheduled access WBAN This is an open access article under the CC BY-SA license. Corresponding Author: Marwa Boumaiz Laboratory of Artificial Intelligence Data Sciences and Emerging Systems (Ecole Nationale des Sciences Appliquées) Sidi Mohamed Ben Abdellah University Avenue My Abdallah Km 5, Route d'Imouzzer, Fès BP 72, Morocco Email: marwaboumaiz@gmail.com 1. INTRODUCTION Wireless body area networks widely known as WBANs, are composed of tiny body sensors, and wirelessly linked to each other to form a network. This emerging technology is nowadays included in several domains of applications [1]-[3], mainly the medical ones. Non-medical applications are numerous including military, entertainment, assisted living, sports and serious gaming [4], etc. However, when applied in medical services, these systems can facilitate the supervision of simple physiological signs such as blood pressure, electrocardiogram (ECG) [5], and body temperature or be used in more complex operations, such as program changes for pacemakers and implantable defibrillators [6], or even retrieving biokinetic information, in order to collect body movement data, such as acceleration or rotational angular speed [7], [8] and also to adjust the movements of body limbs damaged by car accidents, for example. The gathered data can then be transmitted