Medium Access Control (MAC) for Wireless Body Area Network (WBAN): Superframe structure, multiple access technique, taxonomy, and challenges

Wireless Body Area Networks for Healthcare

Motivated by the increasing need for improved healthcare solutions, Wireless Body Area Networks (WBANs) have shown their great potential in revolutionizing the next generation healthcare through enabling continuous monitoring of health status with early detection of abnormal situations. Such networks are able to support a diverse range of applications with traffic rates ranging from several bits per hour up to 10 megabits per second. For the efficient functionality of these applications, each one poses a specific set of Quality of Service (QoS) requirements to the Medium Access Control (MAC) sub-layer including transmission reliability, timeliness and throughput. However, energy limitations of WBANs make the satisfaction of these requirements a challenging task. The current paper aims to explore the application trends of WBANs in the health field as well as the salient features of the MAC protocols proposed for this class of networks, and to provide a general rule indicating the most suitable MAC technology for WBANs based on the characteristics of the targeted application.

Classifier-Based Data Transmission Reduction in Wearable Sensor Network for Human Activity Monitoring

The recent development of wireless wearable sensor networks offers a spectrum of new applications in fields of healthcare, medicine, activity monitoring, sport, safety, human-machine interfacing, and beyond. Successful use of this technology depends on lifetime of the battery-powered sensor nodes. This paper presents a new method for extending the lifetime of the wearable sensor networks by avoiding unnecessary data transmissions. The introduced method is based on embedded classifiers that allow sensor nodes to decide if current sensor readings have to be transmitted to cluster head or not. In order to train the classifiers, a procedure was elaborated, which takes into account the impact of data selection on accuracy of a recognition system. This approach was implemented in a prototype of wearable sensor network for human activity monitoring. Real-world experiments were conducted to evaluate the new method in terms of network lifetime, energy consumption, and accuracy of human activity recognition. Results of the experimental evaluation have confirmed that, the proposed method enables significant prolongation of the network lifetime, while preserving high accuracy of the activity recognition. The experiments have also revealed advantages of the method in comparison with state-of-the-art algorithms for data transmission reduction.

Performance Enhancement of IEEE 802.15.6 Using Collision Avoidance Technique

Research related to Wireless Body Area Networks (WBAN) has recently gained more attention due to its application in enabling smart healthcare systems. A WBAN consists of several sensing nodes and a dedicated coordinator. The distributed nodes communicate with the coordinator by accessing the physical communication channel in a randomly distributed fashion. Random channel access may cause frame re-transmission of corrupted frames due to frame collisions. As a result of that, there will be degradation in the WBAN throughput, an increase in delay, and a waste of node energy. Nodes within a WBAN can be classified using specific user priorities allowing for prioritized communication to reduce possible frame collisions. To improve the performance and energy efficiency, this work aims to reduce collisions among nodes that belong to the same users’ priority (homogeneous collisions) and collisions among nodes of different users’ priorities (heterogeneous collisions). Homogeneous collisions can be reduced by scaling the minimum Contention Window (CW) among nodes within the same user priority, whereas heterogeneous collisions can be reduced by allowing higher user priority nodes to transmit while lower user priority nodes enter into a backoff state. This paper presents an analytical model and extensive simulations to show the enhanced performance of the proposed collision avoidance mechanism. The results show that the throughput and node energy efficiency is improved by a factor of three and two times, respectively.

An empower hamilton loop based data collection algorithm with mobile agent for WSNs

In wireless sensor networks (WSNs), sensor devices must be equipped with the capabilities of sensing, computation and communication. These devices work continuously through non-rechargeable batteries under harsh conditions, the batter span of nodes determines the whole network lifetime. Network clustering adopts an energy neutral approach to extend the network life. The clustering methods can be divided into even and uneven clustering. If even clustering is adopted, it will cause the cluster head nodes (CHs) in vicinity of the base station to relay more data and cause energy hole phenomenon. Therefore, we adopt a non-uniform clustering method to alleviate the problem of energy hole. Furthermore, to further balance and remit resource overhead of the entire network, we combined the PEGASIS algorithm and the Hamilton loop algorithm, through a mixture of single-hop and multiple hops mechanisms, inserting a mobile agent node (MA) and designing an optimal empower Hamilton loop is obtained by the local optimization algorithm. MA is responsible for receiving and fusing packet from the CHs on the path. Network performance results show that the proposed routing algorithm can effectively prolong network lifetime, equalize resource expenditure and decrease the propagation delay.

Compatibility enhancement and performance measurement for socket interface with PCIe interconnections

Today the key technology of high-performance computing systems is the emergence of interconnect technology that makes multiple computers into one computer cluster. This technique is a general method in which each constituent node processes its own operation and communicates with different nodes. Therefore, a high-performance network has been required. InfiniBand and Gigabit Ethernet technologies are typical examples of high-performance network. As an alternative to those technologies the development of interconnection technology using PCI Express (Peripheral Component Interconnect Express), officially abbreviated as PCIe or PCI-e, is a high-speed serial computer expansion bus standard, which has characteristics of high speed, low power, and high protocol efficiency is actively under development. In a high-performance network, the TCP/IP protocol consumes CPU resources and memory bandwidth by nature, which is a bottleneck. In this paper, we implement the PCIe based interconnection network system with low latency, low power, RDMA, and other characteristics. We utilize Socket API which is mainly used in the user-level application program rather than the existing MPI and PGAS model interfaces. The implemented PCIe interconnection network system was measured with the metrics as the bandwidth using the Iperf Benchmark which uses the Socket API. The bandwidth at 4 Mbyte of transmission data size was measured to be 1084 Mbyte/s bandwidth based on PCIe, which is about 96 times higher than that of 11.2 Mbyte/s bandwidth based on Ethernet.