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The characteristics of multipath components (MPCs) are addressed in an industrial environment at 1.3 GHz by means of measurements with a multidimensional channel sounder. The maximum likelihood estimator, RiMAX, is used to determine the MPCs parameters and takes into account the diffuse scattering. Both line‐of‐sight (LOS) and obstructed LOS (OLOS) scenarios have been considered, along with the four polarization states. We found that the environment is very rich in multipath, that is on average, about 120 (resp. 70) MPCs in LOS (resp. OLOS) scenario due to the presence of several metallic reflectors. The azimuthal angle implies clustering of the MPCs, and therefore, the estimated MPCs are grouped in clusters using the K‐powers‐means algorithm based on the multipath component distance. In general, one to four clusters are determined with three clusters occurring with the highest probability, regardless of the scenario. Next, the intra‐cluster parameters have been determined, and we show that the root‐mean‐square (rms) delay spread and rms angular spread follow a gamma distribution, regardless of the polarization. The MPC characteristics agree with the results in the literature and can be valuable when deploying a wireless sensor network in industrial environments. [ABSTRACT FROM AUTHOR]

The characteristics of multipath components (MPCs) are addressed in an industrial environment at 1.3 GHz by means of measurements with a multidimensional channel sounder. The maximum likelihood estimator, RiMAX, is used to determine the MPCs parameters and takes into account the diffuse scattering. Both line‐of‐sight (LOS) and obstructed LOS (OLOS) scenarios have been considered, along with the four polarization states. We found that the environment is very rich in multipath, that is on average, about 120 (resp. 70) MPCs in LOS (resp. OLOS) scenario due to the presence of several metallic reflectors. The azimuthal angle implies clustering of the MPCs, and therefore, the estimated MPCs are grouped in clusters using the K‐powers‐means algorithm based on the multipath component distance. In general, one to four clusters are determined with three clusters occurring with the highest probability, regardless of the scenario. Next, the intra‐cluster parameters have been determined, and we show that the root‐mean‐square (rms) delay spread and rms angular spread follow a gamma distribution, regardless of the polarization. The MPC characteristics agree with the results in the literature and can be valuable when deploying a wireless sensor network in industrial environments. [ABSTRACT FROM AUTHOR]

The polarimetric massive multiple-input multiple-output (MIMO) radio channel of an indoor line-of-sight scenario is investigated at 1.35 GHz using a real-time radio channel sounder. The 8 x 12 massive MIMO transmitter is constructed using a hybrid architecture including a vertical uniform linear array translated at different horizontal positions forming a virtual, yet realistic, uniform rectangular array. The performance of the system is evaluated with six users distributed in the room for different polarisation schemes and receiver orientations using propagation channel-based metrics (such as receiver spatial correlation and Rician factor) and system-oriented metrics such as sum-rate capacity and signal to interference and noise ratio. The results show a clear dependence of the performance to the polarisation schemes and receiver orientation and showing that when facing the array, cross-polarisation can be very beneficial. Furthermore, it is concluded that the additional degree of freedom brought by the polarisation diversity can contribute to improve spectral efficiency (~20% depending on the configuration), paving the way for further capacity enhancements in massive MIMO systems. It was also found that the receiver spatial correlation can be modelled using a Burr distribution. [ABSTRACT FROM AUTHOR]

In this study, the authors present a measurement-based analysis of the indoor radio channel characteristics of both the specular and dense multipath components [specular part of the channel (SMC) and diffuse part of the channel] at 94 GHz within a 3 GHz bandwidth. On the basis of an investigation of the frequency stationarity of this band, they have selected multiple sub-bands to perform their evaluation. A method is developed that allowed for the estimation of the specular propagation paths, after which the remainder is regarded as the diffuse spectrum. Radio channel characteristics such as the path loss, root-meansquare delay spread, and the SMC ratio have been calculated as a function of transmitter-receiver distance, and in the different sub-bands. On the basis of the diffuse spectrum, the behaviour of the reverberation time is analysed for the first time in the 94 GHz band. [ABSTRACT FROM AUTHOR]

This study analyses the multiple-input multiple-output (MIMO) capacity in a residential house. The capacity calculation is based on physical radio channels estimated from channel sounding measurements. Both specular and dense multipath components are estimated from the channel sounding data with the RiMAX maximum-likelihood algorithm. In particular, the capacity analysis is made for a 2 × 2 IEEE 802.11n MIMO system that conforms to the legacy mode of the standard and operates in the 2.4 GHz ISM band. The contribution of dense multipath to the channel capacity is quantified by calculating the capacity of radio channels for which the dense multipath is ignored and only the specular multipath is retained. It is found that ignoring dense multipath underestimates the capacity on average by 1.1, 9.1, and 37.8% for line-of-sight, obstructed line-of-sight, and non-line-of-sight situations, respectively. [ABSTRACT FROM AUTHOR]

Nowadays, the harsh industrial environment remains one of the vital challenges for an effective deployment of wireless technologies in factories to promote the industrial upgrade. In this study, a complete solution is proposed for robust radio communications in indoor factories. Herein, measurement setups are integrated with industrial mobile facilities, e.g. an automated guided vehicle and a mobile robot. Calibration is advised for accurately revealing an industrial radio environment. A hybrid sequential design strategy is used to enhance the efficiency of the measurement campaign. This further leads to a surrogate modelling based radio environment map, which facilitates a holistic view and evaluation of the radio quality of service over the target shop floor. In addition, an over‐dimensioning heuristic is proposed to guarantee that every target location can be wirelessly covered by at least two access points (APs). Moreover, the smart switch mechanism dynamically powers on/off the over‐dimensioned APs, so as to ensure full coverage even at the presence of physical disturbance. The investigation on two real factories and the coverage prediction tool WHIPP further demonstrates the solution's effectiveness. Eventually, a rich outlook is drawn for the roadmap towards an artificially intelligent system for robust industrial wireless communications. [ABSTRACT FROM AUTHOR]

Nowadays, the harsh industrial environment remains one of the vital challenges for an effective deployment of wireless technologies in factories to promote the industrial upgrade. In this study, a complete solution is proposed for robust radio communications in indoor factories. Herein, measurement setups are integrated with industrial mobile facilities, e.g. an automated guided vehicle and a mobile robot. Calibration is advised for accurately revealing an industrial radio environment. A hybrid sequential design strategy is used to enhance the efficiency of the measurement campaign. This further leads to a surrogate modelling based radio environment map, which facilitates a holistic view and evaluation of the radio quality of service over the target shop floor. In addition, an over-dimensioning heuristic is proposed to guarantee that every target location can be wirelessly covered by at least two access points (APs). Moreover, the smart switch mechanism dynamically powers on/off the over-dimensioned APs, so as to ensure full coverage even at the presence of physical disturbance. The investigation on two real factories and the coverage prediction tool WHIPP further demonstrates the solution's effectiveness. Eventually, a rich outlook is drawn for the roadmap towards an artificially intelligent system for robust industrial wireless communications. [ABSTRACT FROM AUTHOR]

ABSTRACT In this paper, a power consumption model for both macrocell and microcell base stations is proposed. This model is validated by temporal power measurements on actual base stations, and an excellent agreement is obtained. Furthermore, the power consumption's evolution during the day is investigated by means of these measurements. The energy efficiency of three different wireless technologies is compared namely mobile Worldwide Interoperability for Microwave Access, Long Term Evolution and High Speed Packet Access. With the model proposed, the deployment tool Green Radio Access Network Design is implemented, which allows to design an energy-efficient access network for a predefined area. In general and with the assumptions made, a macrocell base station consumes about 4.4 times more than a microcell base station. However, a microcell base station is less energy efficient than a macrocell base station because of its lower coverage range. Despite this, it is still useful to introduce them in the network as the same coverage can be obtained with a lower total power consumption than with a network where only macrocell base stations are used. Copyright © 2012 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

ABSTRACT As the network of a power distribution company can be very large, maintaining such a network is not only very time-consuming but also very costly, especially when failures occur. A huge amount of effort could be saved by monitoring the substations remotely, which allows, amongst others, to trace failures more efficiently. In this study, such a monitoring network is designed based on WiMAX in 'Flanders', Belgium. To the best of the authors' knowledge, this study differs from previous studies by combining both coverage and cost calculations. Firstly, the number of base stations needed to cover the considered area is determined. Therefore, link budget calculations are performed to obtain the ranges of the base stations. Secondly, the cost to install and maintain the network is determined using the results of the first step. A cost of approximately 6.5 EUR was found per km2 that needs to be covered. This result is very sensitive to possible changes of the technical parameters, which can lead to cost fluctuations between 33.5% and 3007%. Changes in the cost parameters have, however, less impact on the total cost than the technical parameters. Copyright © 2012 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

A multi-implant scenario is considered using insulated dipole antennas for specific locations such as the liver, heart, spleen and the kidneys where implants communicate with a pacemaker acting as a central hub. Wireless communication within human body experiences loss in the form of attenuation and absorption, and to identify these losses, the path loss is studied in this paper for an adult and child heterogeneous human model. Link performance is calculated to investigate the applicability of in-body communication. The specific absorption rate for all these locations is also studied to verify compliance with international safety guidelines. [ABSTRACT FROM AUTHOR]

A correction factor dependent upon frequency, type of phantom, and incident polarization, which should be applied to the measured specific absorption rate is proposed for homogeneous phantoms. It is shown for an application of occupational exposure in the neighborhood of a base station antenna that this correction factor not underestimates realistic exposure of workers. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 652–655, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22249 [ABSTRACT FROM AUTHOR]

The disturbance caused by a measurement probe close to a ground plane is characterized. A trade-off must be made between disturbance and sensitivity. An optimal probe for electromagnetic exposure measurements above a ground plane in the neighborhood of a base station antenna is selected. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 1610–1613, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21694 [ABSTRACT FROM AUTHOR]