Browsing by Author "Moldsvor, Arild"

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    Characterization of the Body-to-Body Propagation Channel for Subjects during Sports Activities
    (IEEE, 2018-02-18) Mohamed, Marshed; Cheffena, Michael; Moldsvor, Arild
    Body-to-body wireless networks (BBWNs) have great potential to find applications in team sports activities among others. However, successful design of such systems requires great understanding of the communication channel as the movement of the body components causes time-varying shadowing and fading effects. In this study, we present results of the measurement campaign of BBWN during running and cycling activities. Among others, the results indicated the presence of good and bad states with each state following a specific distribution for the considered propagation scenarios. This motivated the development of two-state semi-Markov model, for simulation of the communication channels. The simulation model was validated using the available measurement data in terms of first and second order statistics and have shown good agreement. The first order statistics obtained from the simulation model as well as the measured results were then used to analyze the performance of the BBWNs channels under running and cycling activities in terms of capacity and outage probability. Cycling channels showed better performance than running, having higher channel capacity and lower outage probability, regardless of the speed of the subjects involved in the measurement campaign.
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    A Dynamic Channel Model for Indoor Wireless Signals: Working Around Interference Caused by Moving Human Bodies
    (IEEE, 2018-02-16) Mohamed, Marshed; Cheffena, Michael; Fontán, Fernando Pérez; Moldsvor, Arild
    The use of indoor wireless devices has substantially increased in recent years. This escalation is due to the expansion of traditional communication devices, such as mobile phones and laptop computers, to less traditional ones, such as wirelessly communicating sensor nodes present in smart homes, office buildings, and industrial environments. The placement of these nodes varies considerably from one application to the next, but, when the nodes are placed indoors and within the vicinity of human height, a body's movement can cause significant time-varying channel conditions. The movement is even more compelling in such networks because of the power constraints involved [1]. Thus, an accurate study on the impact of a moving body and the characteristics of indoor propagation channels is important.
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    Physical-Statistical Channel Model for Off-body Area Network
    (IEEE, 2017-01-02) Mohamed, Marshed; Cheffena, Michael; Moldsvor, Arild; Fontán, Fernando Pérez
    In this letter, a physical-statistical-based channel model for off-body wireless communications is presented. The model utilizes a dynamic human walking model, which provides detailed description of the movement of the different body parts. The received signal is composed of a direct component, which might be subject to shadowing by the body parts, and a multipath component due to reflections from the environmental scatterers. The uniform theory of diffraction (UTD) is utilized to accurately calculate the time-varying shadowing and scattering effects of the direct signal due to the moving of body parts. A Rayleigh distribution is used to represent the multipath fading effects by the scatterers around the human body. The model is validated in terms of first- and second-order statistics using 2.36 GHz measurement data, showing good agreement.
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    Propagation Measurements for IQRF Network in an Urban Environment
    (MDPI, 2022-09-16) Bouzidi, Mohammed; Mohamed, Marshed; Dalveren, Yaser; Moldsvor, Arild; Cheikh, Faouzi Alaya; Derawi, Mohammad
    Recently, IQRF has emerged as a promising technology for the Internet of Things (IoT), owing to its ability to support short- and medium-range low-power communications. However, real world deployment of IQRF-based wireless sensor networks (WSNs) requires accurate path loss modelling to estimate network coverage and other performances. In the existing literature, extensive research on propagation modelling for IQRF network deployment in urban environments has not been provided yet. Therefore, this study proposes an empirical path loss model for the deployment of IQRF networks in a peer-to-peer configured system where the IQRF sensor nodes operate in the 868 MHz band. For this purpose, extensive measurement campaigns are conducted outdoor in an urban environment for Line-of-Sight (LoS) and Non-Line-of-Sight (NLoS) links. Furthermore, in order to evaluate the prediction accuracy of well-known empirical path loss models for urban environments, the measurements are compared with the predicted path loss values. The results show that the COST-231 Walfisch–Ikegami model has higher prediction accuracy and can be used for IQRF network planning in LoS links, while the COST-231 Hata model has better accuracy in NLoS links. On the other hand, the effects of antennas on the performance of IQRF transceivers (TRs) for LoS and NLoS links are also scrutinized. The use of IQRF TRs with a Straight-Line Dipole Antenna (SLDA) antenna is found to offer more stable results when compared to IQRF (TRs) with Meander Line Antenna (MLA) antenna. Therefore, it is believed that the findings presented in this article could offer useful insights for researchers interested in the development of IoT-based smart city applications.
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    Wideband Channel Characterization for 6G Networks in Industrial Environments
    (MDPI, 2021-03-12) Al-Saman, Ahmed; Mohamed, Marshed; Cheffena, Michael; Moldsvor, Arild
    Wireless data traffic has increased significantly due to the rapid growth of smart terminals and evolving real-time technologies. With the dramatic growth of data traffic, the existing cellular networks including Fifth-Generation (5G) networks cannot fully meet the increasingly rising data rate requirements. The Sixth-Generation (6G) mobile network is expected to achieve the high data rate requirements of new transmission technologies and spectrum. This paper presents the radio channel measurements to study the channel characteristics of 6G networks in the 107–109 GHz band in three different industrial environments. The path loss, K-factor, and time dispersion parameters are investigated. Two popular path loss models for indoor environments, the close-in free space reference distance (CI) and floating intercept (FI), are used to examine the path loss. The mean excess delay (MED) and root mean squared delay spread (RMSDS) are used to investigate the time dispersion of the channel. The path loss results show that the CI and FI models fit the measured data well in all industrial settings with a path loss exponent (PLE) of 1.6–2. The results of the K-factor show that the high value in industrial environments at the sub-6 GHz band still holds well in our measured environments at a high frequency band above 100 GHz. For the time dispersion parameters, it is found that most of the received signal energy falls in the early delay bins. This work represents a first step to establish the feasibility of using 6G networks operating above 100 GHz for industrial applications.