Energy Hole Analysis for Energy Efficient Routing in BANs K. Latif 1 , N. Javaid 1 , A. Iqbal 1 , Z. A. Khan 2 , U. Qasim 3 , T. A. Alghamdi 4 1 COMSATS Institute of Information Technology, Islamabad, Pakistan. 2 Internetworking Program, FE, Dalhousie University, Halifax, Canada. 3 University of Alberta, Alberta, Canada. 4 Umm Al-Qura University, Makkah, Saudi Arabia. Abstract—Wireless Body Area sensor Networks (WBANs) enable innovative health care monitoring. Limited energy source of a sensor node limits WBANs for long time monitoring of health care. Efficient energy utilization is therefore one of the research challenges in WBANs. In this research work we analysed energy utilization of popular routing techniques. We formu- late a mathematical framework to identify energy utilization in transmission, receive and over-hearing processes. Simulation results show that how distance, packet size, and over-hearing effect different routing techniques from energy consumption perspective. From the analysis, we produced useful results which are helpful in: identifying overloaded nodes in the network which may cause creation of energy holes, and in designing new routing techniques for specific WBANs application. I. I NTRODUCTION WBANs is a new emerging area in health care moni- toring. WBAN enables remote and real time monitoring of biochemical and physiological parameters of human body [1]. In WBANs, sensor nodes are placed on and inside human body. Sensor nodes collect information from human body, process information and then jointly or individually transmit information to coordinator. Coordinator is a kind of personal device which acts as a gateway between sensor nodes and outside world. There are basically two types of nodes in WBAN; sensor nodes and coordinator node. We use the word node for sensor node and coordinator for coordinator node in rest of this research paper. In WBANs, nodes are equipped with limited energy reser- voir. All capabilities of WBAN depend on the single source of energy attached. In order to get maximum and reliable feed back from WBANs, efficient energy consumption of WBANs is a hot research challenge . Although energy consumption is an explicit controlling parameter of physical layer however, each layer implicitly tries to contribute in controlling energy consumption. This research work also focuses on analysis of energy consumption at routing layer. According to IEEE 802.15.6 working group, nodes in WBAN form single-hop, multi-hop, or star topology to forward data to coordinator [2]. In rest of this paper we name single-hop as Direct Transmission Technique (DTT), multi- hop as Intermediate node Transmission Technique (ITT), and star topology as Cluster Based Technique (CBT). Whatever the routing technique is, postural body movement, limitation of bandwidth, interference and temperature rise, and limitation of packet-hop count are some of the routing challenges [3]. In this research work, we formulate a mathematical model for analysing energy consumption during transmission, receive, and over-hearing processes of DTT, ITT and CBT routing strategies. However, we also discuss creation of energy holes; energy hole is a phenomena in which a node is overloaded for transmission, receive, or overhearing due to which its energy depletes quickly. In the simulation section, we analysed which routing technique is more economical from energy conservation perspective and which is less. II. RELATED WORK In [4], authors analysed energy consumption in terrestrial sensor networks. An-Feng Liu, et.al., formulated a mathemati- cal model for impact analysis of distance, cluster radius, rate of data aggregation on different routing techniques for terrestrial sensor networks. Rai, et.al., in [5], formulated a lifetime model for re- placement of sensor nodes in terrestrial sensor networks. Their research focuses on specific applications like, measuring traffic intensity, habitat and climate monitoring. Authors find out the life time of a sensor node subject to environmental constraints. Multi-criterion optimisation technique for energy efficiency of wireless sensor networks is presented in [7]. Authors introduced a matrix manipulation based technique for selection of multiple options on priority basis, for energy efficiency of sensor nodes. In [8], authors provided analytical analysis of energy con- sumption of Medium Access Control protocols for WBANs. Authors also elaborated path-loss model for in-body, on-body, and off-body communication in WBANs. Distance Aware Relaying Energy-efcient (DARE) protocol is presented by A. Tauqir, et.al., in [9]. Authors presented a novel routing technique for monitoring patients vital signs in ward of a hospital. Authors evaluated their technique for four different scenarios of mobile sink. III. ON-BODY NETWORK ARCHITECTURE To analyse the energy consumption in WBAN, we assume ten sensor nodes placed on human body. These sensor nodes are placed for measuring different vital signs of human body. Placement of the nodes is shown in figure 1. Placement of nodes is such that it covers maximum and minimum distances from coordinator. Coordinator is placed on left side of front 2014 IEEE 28th International Conference on Advanced Information Networking and Applications 1550-445X/14 $31.00 © 2014 IEEE DOI 10.1109/AINA.2014.112 920