A comprehensive survey of wireless body area networks on PHY, MAC, and network layers solutions

Recent advances in microelectronics and integrated circuits, system-on-chip design, wireless communication and intelligent low-power sensors have allowed the realization of a Wireless Body Area Network (WBAN). A WBAN is a collection of low-power, miniaturized, invasive/non-invasive lightweight wireless sensor nodes that monitor the human body functions and the surrounding environment. In addition, it supports a number of innovative and interesting applications such as ubiquitous healthcare, entertainment, interactive gaming, and military applications. In this paper, the fundamental mechanisms of WBAN including architecture and topology, wireless implant communication, low-power Medium Access Control (MAC) and routing protocols are reviewed. A comprehensive study of the proposed technologies for WBAN at Physical (PHY), MAC, and Network layers is presented and many useful solutions are discussed for each layer. Finally, numerous WBAN applications are highlighted

Enhancement of the duty cycle cooperative medium access control for wireless body area networks

This paper presents a novel energy-efficient and reliable connection to enhance the transmission of data over a shared medium for wireless body area networks (WBAN). We propose a novel protocol of two master nodes-based cooperative protocol. In the proposed protocol, two master nodes were considered, that is, the belt master node and the outer body master node. The master nodes work cooperatively to avoid the retransmission process by sensors due to fading and collision, reducing the bit error rate (BER), which results in a reduction of the duty cycle and average transmission power. In addition, we have also presented a mathematical model of the duty cycle with the proposed protocol for the WBAN. The results show that the proposed cooperative protocol reduced the BER by a factor of 4. The average transmission power is reduced by a factor of 0.21 and this shows the potential of the proposed technique to be used in future wearable wireless sensors and systems

TRW-MAC: A thermal-aware receiver-driven wake-up radio enabled duty cycle MAC protocol for multi-hop implantable wireless body area networks in Internet of Things

Implantable Wireless Body Area Network (IWBAN), a network of implantable medical sensors, is one of the emerging network paradigms due to the rapid proliferation of wireless technologies and growing demand of sophisticated healthcare. The wireless sensors in IWBAN is capable of communicating with each other through radio frequency (RF) link. However, recurring wireless communication inside the human body induces heat causing severe thermal damage to the human tissue which, if not controlled, may appear as a threat to human life. Moreover, higher propagation loss inside the human body as well as low-power requirement of the sensor nodes necessitate multi-hop communication for IWBAN. A IWBAN also requires meeting certain Quality of Service demands in terms of energy, delay, reliability etc. These pressing concerns engender the design of TRW-MAC: A thermal-aware receiver-driven wake-up radio enabled duty cycle MAC protocol for multi-hop IWBANs in Internet of Things. TRW-MAC introduces a thermal-aware duty cycle adjustment mechanism to reduce temperature inside the body and adopts wake-up radio (WuR) scheme for attaining higher energy efficiency. The protocol devises a wake-up estimation scheme to facilitate staggered wake-up schedule for multi-hop transmission. A superframe structure is introduced that utilizes both contention-based and contention free medium access operations. The performance of TRW-MAC is evaluated through simulations that exhibit its superior performance in attaining lower thermal-rise as well as satisfying other QoS metrics in terms of energy-efficiency, delay and reliability

Modeling on Body Delay Tolerant Network Sink Locality of Wireless Body Area Networks for Different Body Postures

Due to the recent advancements in the field of wireless communication and Wireless Sensor Networks, the Wireless Body Area Networks (WBANs) have become an area of concern for researchers. In military operations, patient monitoring, sports field, among other wireless body area networks is used for real time monitoring and smart sensing for eHealth operations. In these WBAN, disconnections between the body sensors occur quite often and sometimes of significant duration due to the postural mobility nature of the human. These consequently affects the efficiency of the entire network hence the need for Delay Tolerant Network (DTN). The DTN minimizes delays and adapts itself to cope with long delays if they occur. One of the vital mechanisms that can be employed to enhance the efficiency of the network is to determine the optimal postural locality of the sink nod

Study and overview on WBAN under IEEE 802.15.6

WBAN (wireless body area networks) is an upcoming technology which stands to be a base for wearable and implantable sensors. The IEEE 802.15.6 formulates the physical and medium access for body area networks. The Body area networks can be implemented in several applications like health monitoring, ambient living environments and consumer electronics. This paper gives a clear overview about the functions of WBAN. The medium access layers and the physical layers of IEEE 802.15.6 are deeply examined and studied in this work. The access mechanisms of the protocol are explained in this paper. A clear literature review has also been stated to know the current state of art of this technology. The future possibilities and area to be explored also has been defined in this work

Reliable and Energy Efficient Network Protocols for Wireless Body Area Networks

In a wireless Body Area Network (WBAN) various sensors are attached on clothing, on the body or are even implanted under the skin. The wireless nature of the network and the wide variety of sensors offers numerous new, practical and innovative applications. A motivating example can be found in the world of health monitoring. The sensors of the WBAN measure for example the heartbeat, the body temperature or record a prolonged electrocardiogram. Using a WBAN, the patient experiences a greater physical mobility and is no longer compelled to stay in a hospital. A WBAN imposes the networks some strict and specific requirements. The devices are tiny, leaving only limited space for a battery. It is therefore of uttermost importance to restrict the energy consumption in the network. A possible solution is the development of energy efficient protocols that regulate the communication between the radios. Further, it is also important to consider the reliability of the communication. The data sent contains medical information and one has to make sure that it is correctly received at the personal device. It is not allowed that a critical message gets lost. In addition, a WBAN has to support the heterogeneity of its devices. This thesis focuses on the development of energy efficient and reliable network protocols for WBANs. Considered solutions are the use of multi-hop communication and the improved interaction between the different network layers. Mechanisms to reduce the energy consumption and to grade up the reliability of the communication are presented. In a first step, the physical layer of the communication near the human body is studied and investigated. The probability of a connection between two nodes on the body is modeled and used to investigate which network topologies can be considered as the most energy efficient and reliable. Next, MOFBAN, a lightweight framework for network architecture is presented. Finally, CICADA is presented: a new cross layer protocol for WBANs that both handles channel medium access and routing

Human-Centric Wireless Communication Networks

This thesis covers two main topics: the design and performance evaluation of Wireless Body Area Networks (WBANs), and the simulation and mathematical modeling of Delay Tolerant Networks (DTNs). Different Medium Access Control (MAC) protocols for WBANs are implemented on dedicated hardware in order to evaluate, through extensive measurement campaigns, the performance of the network in terms of packet loss rate, delay and energy consumption. Novel solutions to cope with body shadowing and to improve the coexistence with other wireless technologies, are presented and evaluated. An analytic model for the CSMA/CA protocol defined in the IEEE 802.15.6 standard is also presented. The benefits of offloading part of the traffic carried by a wireless backbone to a DTN composed of mobile nodes in a urban environment, is also investigated. A more analytic approach, mainly using tools from stochastic geometry and Markov chains theory, is used to develop a mathematical framework for the evaluation of the performance of routing rules for DTNs

Wireless Techniques for Body-Centric Cooperative Communications

Body-centric and cooperative communications are new trends in telecommunications field. Being concerned with human behaviour, body-centric communication networks, also known as Wireless Body Area Networks (WBANs), are suitable for a wide variety of applications. The advances in the miniaturisation of embedded devices to be placed on or around the body, foster the diffusion of these systems, where the human body is the key element defining communication characteristics. Cooperative communications paradigm, on the other hand, is one of the emerging technologies that promises significantly higher reliability and spectral efficiency in wireless networks. This thesis investigates possible applications of the cooperative communication paradigm to body-centric networks and, more generally, to Wireless Sensor Networks (WSNs). Firstly, communication protocols for WBANs are in the spotlight. Performance achieved by different approaches is evaluated and compared through experimentation providing guidelines for choosing appropriate protocol and setting protocol parameters to meet application requirements. Secondly, a cooperative Multiple Input Multiple Output (MIMO) scheme for WBANs is presented. The scheme, named B-MIMO, exploits the natural heterogeneity of the WBAN propagation channel to improve energy efficiency of the system. Finally, a WSN scenario is considered, where sensor nodes cooperate to establish a massive MIMO-like system. The analysis and subsequent optimisation show the advantages of cooperation in terms of energy efficiency and provide insights on how many nodes should be deployed in such a scenario