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Top1. Introduction
One of the most promising application areas of Wireless Sensor Networks (WSN) in recent years has been in the field of Bio-medical research. Therefore, the advancement of small sized biosensors and wireless communication technology, have fostered a new type of network called WBAN (Liolios, Doukas, Fourlas, & Maglogiannis, 2010; Chen et al., 2011; Pantelopoulos, & Bourbakis, 2010; Bradai, Chaari, & Kamoun, 2011; Barth, Hanson, Powell, Unluer, Wilson, & Lach, 2008). In the health field, the WBAN consists of a set of medical sensors (ECG, EEG, SOP…) and a coordinator (PDA or a smart phone) implanted in or on the user’s body. These devices aim to collect, store and process patient’s physiological parameters (heartbeat, blood pressure, body temperature …) and provide him ubiquitous healthcare services.
To provide smart healthcare services for a human body, a novel wireless technology is needed. The IEEE adopted the WBAN as the next generation of wireless technology for WPANs and the WBAN starts as a task group (TG) of Wireless Personal Area
Networks (WPANs) from November, 2007 (IEEE 802.15 WPAN Task Group 6 BAN; Li, & Kohno, 2007; Li, Takizawa, Zhen, & Kohno, 2007).
The IEEE 802.15.6 (IEEE Standards Association. 802.15.6, 2012) is the WBAN standard and it aims to support the following design aspects: a low complexity, low cost, low power and reliable transmission. It allows a very short transmission range with a flexible data rate. It also adopts the 1-hop star and the 2-hop extended star topology and four channel models among the WBAN devices.
In a WBAN, all protocol stack layers (application, network, MAC and physical) play an important role for ensuring precise readings of patient health and transmitting accurate information to medical staff. Modularity design of traditionally architectures that follow strict layering principles is an attractive tool for providing interoperability. However, lack of cooperation between different layers imposed by such layered models may limit the efficiency of challenging and resource limited networks such WBAN. Furthermore, the specificity of the operating environment and treated data make WBANs unique compared to other networks. Thereby it is mandatory that node and Hub architecture design be done consistent with the previous cited WBAN standard specifications.
In our best of knowledge, none of proposed WBAN architectures has responded to all listed requirements.
Consequently, to ensure layer cooperation, interoperability and overall WBAN efficiency, in this paper we propose a cross-layer designed node and hub management entities wherein different modules and layers interact to ensure healthcare services according to IEEE 802.15.6 specifications. Therefore, owing to combination of modular and cross layer design, proposed architectures enhance WBAN QoS and ensure traffic differentiation aswell as interoperability.
Furthermore, we propose an Adaptive Two-hop Routing protocol (ATR) that ensures reliable data dissemination and topology update in compliance with the WBAN standard.
The rest of paper is organized as follows. In section 2, we present related works to WBAN cross-layer data dissemination and routing protocols. In section 3, we review the key aspects of IEEE 802.15.6 standard. In section 4 and 5 we highlight the network components, network topology and our assumptions. NME and HME architectures are respectively presented in sections 6 and 7. Further, the ATR protocol is presented in section 8. Performance evaluations are depicted in section 9. Finally, section 10 concludes this paper and highlights the future works that will be carried related to this topic.