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

Wearable and Implantable Wireless Sensor Network Solutions for Healthcare Monitoring

Wireless sensor network (WSN) technologies are considered one of the key research areas in computer science and the healthcare application industries for improving the quality of life. The purpose of this paper is to provide a snapshot of current developments and future direction of research on wearable and implantable body area network systems for continuous monitoring of patients. This paper explains the important role of body sensor networks in medicine to minimize the need for caregivers and help the chronically ill and elderly people live an independent life, besides providing people with quality care. The paper provides several examples of state of the art technology together with the design considerations like unobtrusiveness, scalability, energy efficiency, security and also provides a comprehensive analysis of the various benefits and drawbacks of these systems. Although offering significant benefits, the field of wearable and implantable body sensor networks still faces major challenges and open research problems which are investigated and covered, along with some proposed solutions, in this paper

An Intelligent Multi-stage Channel Acquisition Model for CR-WBANs: A Context Aware Approach

Cognitive Radio (CR) came as a solution to mitigate challenges that wireless body area networks (WBANs) suffer from. CR is an intelligence-based technology that senses, observes, and learns from its operating environment to access licensed bands in the spectrum when they are not being utilized by primary users. Deploying a CR technology in WBANs applications, enhances spectrum scalability, increases system robustness, and decreases latency. Accordingly, CR-WBANs help in building a more efficient and reliable ubiquitous healthcare system than conventional WBANs do. However, CR-WBANs are still evolving, and many challenges need to be investigated, in particular, is how to acquire a channel and prioritize data streams among multiple CR-users (i.e., multiple patients) based on the severity of their health status, in a manner to decrease network latency and increase network scalability. To address this challenge, this work proposes a novel intelligent channel acquisition model for multiple CR-WBANs within ubiquitous healthcare system, whereby contextual data, namely, channel properties, intra-node characteristics, and patients’ profile information, is integrated in channel acquisition decision process. The proposed work is a multi-stage fusion system that is composed of local and global decisions units. A fuzzy logic system is utilized to make decisions in the local unit, which are sensing the channel availability and assessing the severity of patients' health status. Moreover, a neural network is employed as a global sensing decision center, whereby local sensing decisions, channel properties, and intra-node characteristics are augmented in the decision process. Furthermore, a cluster-based heuristic algorithm is formulated, in the global decision unit, to prioritize data streams among CR-users based on the criticality of their health conditions (i.e., acute, urgent, and normal). Patients' local health assessments and avatars (e.g., age, medical history, etc.) are exploited in the prioritization process

Generalized Activity Assessment computed fully distributed within a Wireless Body Area Network

Currently available wearables are usually based on a single sensor node with integrated capabilities for classifying different activities. The next generation of cooperative wearables could be able to identify not only activities, but also to evaluate them qualitatively using the data of several sensor nodes attached to the body, to provide detailed feedback for the improvement of the execution. Especially within the application domains of sports and health-care, such immediate feedback to the execution of body movements is crucial for (re-)learning and improving motor skills. To enable such systems for a broad range of activities, generalized approaches for human motion assessment within sensor networks are required. In this paper, we present a generalized trainable activity assessment chain (AAC) for the online assessment of periodic human activity within a wireless body area network. AAC evaluates the execution of separate movements of a prior trained activity on a fine-grained quality scale. We connect qualitative assessment with human knowledge by projecting the AAC on the hierarchical decomposition of motion performed by the human body as well as establishing the assessment on a kinematic evaluation of biomechanically distinct motion fragments. We evaluate AAC in a real-world setting and show that AAC successfully delimits the movements of correctly performed activity from faulty executions and provides detailed reasons for the activity assessment

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

An adaptive energy efficient MAC protocol for RF energy harvesting WBANs

Continuous and remote health monitoring medical applications with heterogeneous requirements can be realized through wireless body area networks (WBANs). Energy harvesting is adopted to enable low-power health applications and long-term monitoring without battery replacement, which have drawn significant interest recently. Because energy harvesting WBANs are obviously different from battery-powered ones, network protocols should be designed accordingly to improve network performance. In this article, an efficient cross-layer media access control protocol is proposed for radio frequency powered energy harvesting WBANs. We redesigned the superframe structure, which can be rescheduled by the coordinator dynamically. A time switching (TS) strategy is used when sensors harvest energy from radio frequency signals broadcast by the coordinator, and a transmission power adjustment scheme is proposed for sensors based on the energy harvesting efficiency and the network environment. Energy efficiency can be effectively improved that more packets can be uploaded using limited energy. The length of the energy harvesting period is determined by the coordinator to balance the channel resources and energy requirements of sensors and further improve the network performance. Numerical simulation results show that our protocol can provide superior system performance for long-term periodic health monitoring applications

A self-organized dynamic clustering method and its multiple access mechanism for multiple WBANs

Due to its wide application range and attractive features, wireless body area networks (WBANs) is considered as a revolutionary technology, which is envisaged to change how people manage and think about their health and their life styles. In this paper, we propose a self-organized dynamic clustering (SDC) method and its multiple access mechanism to mitigate the interference and improve the QoS in multiple WBANs environment. To the best of our knowledge, this is the first paper that focuses on the spectrum allocation for multiple WBANs. We borrow the concepts of cell and cluster from cellular networks to allocate the channels for different WBANs. The clustering is self-organized to improve the data transmission for intra-WBAN communication by the information exchange via inter-WBAN communication. Additionally, based on the cluster architecture, an inter-WBAN relaying (IWR) protocol for packets with low privacy or high reliability is also investigated. The simulation results show that SDC has better signal to interference ratio compared with existing framework. Besides, SDC and IWR also provide better QoS performance in terms of higher data packet delivery ratio and lower packet delay