The global problem of students’ health deterioration has been identified worldwide and the condition is becoming seriously dangerous in many industrial nations where students are under huge pressure for performance. One practical solution to this menacing problem is to enhance the classes by injecting extra movements into the existing lectures by making a better use of computer technology in the form of integrating the augmented reality (AR) through an image-sensing system to engage the students’ dynamics. The authors’ tests provide extensive measurement results, but here they present those related to the use of the new technology mainly in connection with studying the impact of AR on user perception, namely perceived exertion (PRE), and the physical fitness indicator, cardiorespiratory endurance (CRE). In this study, using the computer technology in the form of AR interacting with images, the authors study the impact of AR and report their experimental measurement results for PRE and CRE as two main factors of students’ physical fitness. In connection with the PRE statistical data, the CRE results for over 364 students show significant improvements in some exercises more than others.

Distributed space-time coding (DSTC) with an efficient relaying protocol, referred to as amplify-and-forward and decode-and-forward (DF–AF) selection relaying, has not received much attention yet. In the DF–AF selection relaying-aided DSTC transmissions, each relay could adaptively process the received signal according to its decoding state to improve the performance. In this study, the authors analyse the pairwise error probability (PEP) performance, the diversity order and the union bound on the error probability of the DSTC with DF–AF selection relaying in cooperative wireless sensor networks. More specifically, by introducing a random variable vector to denote the decoding state of the relays, the upper bounds of PEP are derived first for the DSTC with DF–AF selection relaying based on the Chernoff bound. Then, the diversity order and the union bound on the error probability are obtained based on the upper bounds of PEP. Finally, simulation results verify the theoretical analysis and demonstrate that the DSTC with DF–AF selection relaying has better error performance than the DSTC with DF protocol and the DSTC based on AF protocol.

Integration of miniature sensors composes a wireless body area network (WBAN), which enables remote health monitoring. To make this technology widely acceptable in the society, some studies suggest commonly used gadgets such as cell phones or laptops as a hub for WBANs. In these cases, envisaged medical and non-medical applications of WBANs must have the same priority unless in emergency situations. Also, medical applications of WBANs need some strict requirements that are not that important for non-medical applications, such as very low-power consumption or reliability. In addition, channel condition may change in WBANs because of fading effects and this causes packet loss. Therefore proper traffic prioritisation, high reliability and efficient channel utilisation are vitally important issues in these networks. In this study, the authors improve the performance of the medium access control (MAC) protocol of WBANs using an adaptive resource allocation and traffic prioritisation according to the medical situation of user and channel condition. Through adaptively separating and managing the possible traffics of WBANs, the heterogeneous requirements of different applications are provided. Analytical and simulation results show that the proposed MAC protocol outperforms IEEE 802.15.4 and IEEE 802.15.6 MAC protocols in terms of power consumption as well as the channel utilisation and reliability.

This study proposes an algorithm for the design of a distributed protocol for detecting and diagnosing permanent faults in wireless image sensor networks (WISNs). This work explicitly takes into account the possibility of faults in different sections of the image sensor node and communication channel. The fault diagnosis is achieved by disseminating local decision made at each node. Theoretical analysis and simulation results show that high level (>0.95) of diagnosis accuracy can be achieved for a wide range of fault rates. Correctness and complexity proofs are provided, and they show that the proposed algorithm performs better than the existing protocols from both communication and energy complexity perspective. Analytical study shows that time complexity is O(n _c) and message complexity O(n) for an n-node WISN where n _c is the number of cluster heads.

Recent technological advances in integrated circuits, wireless communications and physiological sensing have allowed ultra-low power, intelligent-monitoring tiny devices to settle around the human body, forming a wireless body area network (WBAN) to collect information for a particular purpose. As these tiny devices are low-weighted and energy-restricted, ‘energy efficiency’ becomes a key issue. Built in 2012 to facilitate the development of WBAN, the ‘IEEE 802.15.6’ standard operates with one-hop star and two-hop restricted tree topologies. Its two-hop extension protocol has relaying nodes (working as a microhub), process node joining and schedule two-hop transmissions, thus reducing their lifetime. To reduce the energy consumption and overhead for relaying nodes, the authors introduce a new two-hop extension protocol which lets the generally better resource-equipped hub directly transmit packets to the downlink relayed nodes. Analytical and experimental evaluations show that when advancing ‘IEEE 802.15.6’ in extending the lifetime of relaying nodes with less energy consumption and overhead, the authors’ new protocol also retains its advantages, including longer lifetime for relayed nodes and lower bit error rates.

Wireless sensor network (WSN) localisation has attracted significant research interest. The quality of time-of-flight ranging when used as the basis of localisation, has a direct impact on precision and accuracy. Recently significant attention has been devoted to modelling and analysis of range estimation error (REE) in indoor and cluttered environments. A Gaussianity assumption for the distribution of REE is a common practice in the literature. The motivation of this study is to analyse this assumption. To scrutinise this, rather than relying on computer generated data, a real IEEE 802.15.4 compliant WSN test-bed is used for collecting ranging data, covering outdoor and indoor environments for both line-of-sight and non-line-of-sight propagation conditions. The distribution of REE is analysed using both graphical and numerical goodness-of-fit (GOF) techniques, that is, quantile–quantile plotting, empirical cumulative distribution function plotting, probability density function plotting, linear correlation coefficient (γ) test, kurtosis (K) test, skewness (S) test, Anderson–Darling (A ²) test and chi-squared (χ ²) test. The GOF statistical analysis of the experimental results suggest that REE is not Gaussian distributed. A novel means of enhancement called the range filtration algorithm (RFA) is proposed. The RFA is based on the A ² test, it filters out the range estimates with high errors.

The DRMACSN (distributed and receiver-oriented sensor networks) MAC (medium access control) protocol is a receiver-oriented protocol, which employs channel load sensing scheme to reduce the delay and the energy consumption in the network. This study presents the queuing analysis of the DRMACSN  protocol for DS-CDMA-based wireless sensor networks. In this study, a discrete-time Geom/G/1 and M/G/1 multiple vacation queuing models that are used to model the behaviour of the DRMACSN MAC protocol are discussed. The study provides the results for the packet delay of the DRMACSN MAC protocol through simulations and the analysis. The results show that a reduced delay performance can be achieved by implementing the channel load blocking technique.

The growing interest in applications of wireless sensor networks (WSNs) in vegetation environment has made it important to understand and predict the impact of vegetation on coverage and signal quality. As most of the proposed vegetation attenuation models are mainly based on measurements in temperate climate their prediction accuracy needs to be tested in tropical climate. With the presence of high humidity and high temperature in the tropical climate the attenuation because of vegetation is bound to increase. Very few researches have been reported about the attenuation because of vegetation related to WSN applications in scrub forest and plantation environments from the regions having tropical climate in Indian subcontinent. This study focuses on short-range, near to ground received signal strength measurements at 915 and 2400 MHz to evaluate vegetation attenuation models for planning and deployment of wireless sensor communications/networks in tropical climate for precision agriculture and plantation management applications. The measurements have been done in scrub forest, mango and guava plantation environment. It is found that International Telecommunication Union (ITU) Recommendation (ITU-R) and Weissberger models under predict vegetation because of attenuation, whereas the Cost 235 model has high prediction accuracy in the scrub forest and plantation environments in tropical climate.