Optimum placement of gateway node on human body for real-time healthcare monitoring using WBAN Abstract— The Wireless Body Area Networks (WBAN) is an emerging type of real-time monitoring used in the healthcare sec- tor. It has the potential to revolutionize the healthcare sector by allowing patients not to physically visit doctor clinics or hospitals for medical checkups. But implementing such a system is chal- lenged by many factors. The most important one is energy con- sumption. Energy consumption of all nodes in general and that of the gateway node in particular is critical. The gateway node is re- sponsible for conveying sensor information to medical servers or doctors. Failure of the gateway node means failure of the overall WBAN system of a patient. Thus, extending the life time of the gateway node is a desirable objective in designing WBAN systems. As energy consumption is directly related to the end-to-end delay, Packet Delivery Ratio (PDR) and medium accessibility rate. So, placement on the human body in a location that is affected the least by delay and has high PDR and medium accessibility should be chosen as the placement location for the gateway node. In this pa- per, we identify the optimal placement location on the human body for a gateway node in terms of end-to-end delay, PDR, and back- off duration period. Index Terms— WBAN, Packet Delivery Ratio (PDR), End-to- End Delay, Back-off Duration, Gateway Node. I. INTRODUCTION Recent advancement in wireless technology, networking and embedded sensors has led to the development of Wireless Body Area Network (WBAN) as an emerging technology to improve the quality of human life [1-2]. In healthcare sector, a WBAN is setup through a number of miniaturized sensors on, in or near the human body. These sensors collect and report data via a wireless communication channel towards a node generally re- ferred to as gateway node. The gateway node is further respon- sible to forward the received data to Personal Digital Assistant (PDA) or mobile phone. The data is then forwarded to medical server or doctor via any wireless network including cellular, WiFi, Bluetooth etc. Accordingly, the use of a WBAN will en- able continuous and remote monitoring of patient’s physiolog- ical signals, and this could be benefic to trigger first aid assis- tance and to detect emergency situations [3-4]. One of the key issues among others in WBAN is to select optimum placement for gateway node for efficacious and economical operation of WBAN. As far as we know, very few attempts have been made in the past regarding this issue. In [5], two mechanisms were proposed: relaying and cooperation. The first solution intro- duces relay nodes, which only handle traffic relaying. In the second solution, it relays cooperate in forwarding the data from one node towards the sink. The network lifetime is increased, though the positions of relay nodes are fixed and are not opti- mized. An integer linear programming model which optimizes the number and location of relays to be deployed and the data routing towards the sinks was proposed by minimizing both the network installation cost and the energy consumed for wireless sensors and relays [6]. This work was further extended in [7]. However, relaying is not an optimal solution for migratory pa- tients. In [8-9], the impact of network architecture, maximizing end to end Packet Delivery Ratio (PDR) and minimizing the number of retransmission is investigated. However, the experi- ments were designed in the way that the interval between the transmission of each node is 8 seconds. We think that such an interval is a very long keeping human mobility in perspective. On the other hand, [10] and [11] have done a full-mesh WBAN measurement campaign but the subject was instructed to walk for a series of experiments 3 seconds long, which might be too limited to fully represent human mobility. The author in [12] has done a study on the cooperative communication in WBAN and he has shown the improvements in terms of average proba- bility and average fade duration using a simple forward relay scheme. Here in this paper we try to further investigate the matter. We have simulated sensor nodes attached to different parts of hu- man body. QoS parameter like Packet Delivery Ratio (PDR), End to end delay and medium inaccessibility duration of time referred to as backoff duration is calculated. Three human body postures are assumed here namely walking, standing and sit- ting. The rest of the paper is organized as follow. Section II considers various aspects of WBAN and how energy consumption of a node is related to the three parameters. Sec- tion III is reserved for the simulation environment and results. Section IV concludes the paper. II. ARCHITECTURE, WORKING PRINCIPLE AND ISSUES IN WBAN WBAN is new idea first came to hear in the last century where it was conceived that instead of going to hospital or clinic Abd Ullah Khan Department of Electrical Engineering University of Science & Technology Bannu, Pakistan newabd470@gmail.com Atiqur Rahman Department of Electrical Engineering University of Science & Technology Bannu, Pakistan atiqrehman37@gmail.com Nadim Khan Department of Electrical Engineering University of Science & Technology Bannu, Pakistan imnadim470@gmail.com 978-1-5090-2000-3/16/$31.00 ©2016 IEEE 408