HEAT: H orizontal moveable E nergy-efficient A daptive T hreshold-based Routing Protocol for Wireless Body Area Networks A. Afridi 1,2 , N. Javaid 1 , S. Jamil 1 , M. Akbar 1 , Z. A. Khan 3 , U. Qasim 4 1 COMSATS Institute of Information Technology, Islamabad, Pakistan. 2 Allama Iqbal Open University, Islamabad, Pakistan. 3 Internetworking Program, FE, Dalhousie University, Halifax, Canada. 4 University of Alberta, Alberta, Canada. Abstract—Approaches of using Wireless Body Area Sensor Network (WBASN) in health care applications are getting much popularity. WBASN is a hot topic among the research community. Our proposed Horizontal moveable Energy-efficient Adaptive Threshold-based (HEAT) protocol is well suited for horizontally moving (walking) human body. The on body nodes attached at arms and legs of human body move forward and backward to sink during horizontal movement. We use direct communication for emergency data and multi-hop communication strategy for normal data transmission. Simulation results show that our proposed protocol performs better in terms of stability period and network lifetime. The stability period of HEAT is comparative with direct communication, while it outperforms direct commu- nication in term of network lifetime. Index Terms—Wireless Body area Sensor Network, Network Lifetime, Stability Period, Multi-Hop, Single-Hop, Path Loss, Line of Sight I. I NTRODUCTION Recent advances in the Electronics technology make it possible to develop small and intelligent medical sensors. These sensors are deployed on body or implanted in the human body. Normally, these nodes send data to the sink which is attached to some suitable place on the body. We use nodes and sensors interchangeably in this paper. The nodes sense the desired data and send to the sink. The sink processes and sends this data to some external medical server, via some access point, where it is stored and analyzed. It is inappropriate to use wired network for human body especially when it is moving. The modern health care practices supporting exchange of information between patient and heath care provider are referred as e-Health [1]. These health care systems are now stepping further to become mobile and referred as m-Health [2]. In order to achieve the full benefits of wireless technologies in health care, Wireless Body Area Network (WBAN) are getting much popularity. The term WBAN was think up by Van Dan et al. in [3]. Existing communication techniques of wireless sensor network (WSN) and ad hoc networks are different from those used in WBAN due to different characteristics. Some of examples are: • Energy Limitation: The nodes in WBANs are small in size and have batteries of limited power. • Path Loss: In WBANs path loss is very high as compared to free space. • Vigorous Network Topology: Network topology should be vigorous against the changes occurred due to motion human body. In this work, we enhance the existing routing protocol Reli- ability Enhanced Adaptive Threshold-based Thermal unaware Energy efficient Multi-hop Protocol (RE-ATTEMPT), which is designed only for static human body. On the other hand, HEAT is a multi-hop threshold based protocol for horizontally moving human body. It consists of three phases. In the first phase routing table is updated by exchange of messages. In the second phase nodes are categorized according to the synchronization of their movement and are assigned to either category 1 or category 2. In third phase the sink allocates Time Division Multiple Access (TDMA) based time slots to all nodes for data transmission. Finally the nodes send their data to the sink in allotted time slots. Nodes are equipped with same initial energy, processor and radio transceiver. We assume that sink is supplied with unlimited battery power. Commonly sensed parameters in health care domain are temperature, blood pressure, ECG and heart beat etc. The remainder of this paper is organized as follows: section 2 presents the related work and motivation, section 3 gives brief explanation of our proposed protocol, section 4 is pro- vided with performance evaluation while section 5 gives the conclusion and future work. II. RELATED WORK AND MOTIVATION The propagation of radio signal narrow band or Ultra Wide Band (UWB), along the human body can be divided into two situations, the Line of Sight (LOS) and Non-Line of Sight (NLOS)[4]. In line of sight situation, the effects of body bent and twist are not taken into the account. In LOS situations, simulations are performed by assuming that sender and receiver are at the same side of the body. While in NLOS situations, the sender and receiver are not in direct view. The 2014 28th International Conference on Advanced Information Networking and Applications Workshops 978-1-4799-2652-7/14 $31.00 © 2014 IEEE DOI 10.1109/WAINA.2014.148 474 2014 28th International Conference on Advanced Information Networking and Applications Workshops 978-1-4799-2652-7/14 $31.00 © 2014 IEEE DOI 10.1109/WAINA.2014.148 474