4 research outputs found
Radio frequency channel characterization for energy harvesting in factory environments
This thesis presents ambient energy data obtained from a measurement campaign carried out at an automobile plant. At the automobile plant, ambient light, ambient temperature
and ambient radio frequency were measured during the day time over two days. The measurement results showed that ambient light generated the highest DC power. For plant and operation managers at the automobile plant, the measurement data can be used in system design considerations for future energy harvesting wireless sensor nodes at the plant.
In addition, wideband measurements obtained from a machine workshop are presented in this thesis. The power delay profile of the wireless channel was obtained by using a frequency domain channel sounding technique. The measurements were compared with
an equivalent ray tracing model in order to validate the suitability of the commercial propagation software used in this work.
Furthermore, a novel technique for mathematically recreating the time dispersion created by factory inventory in a radio frequency channel is discussed. As a wireless receiver
design parameter, delay spread characterizes the amplitude and phase response of the radio channel. In wireless sensor devices, this becomes paramount, as it determines the
complexity of the receiver. In reality, it is sometimes difficult to obtain full detail floor plans of factories for deterministic modelling or carry out spot measurements during
building construction. As a result, radio provision may be suboptimal. The method presented in this thesis is based on 3-D fractal geometry. By employing the fractal overlaying algorithm presented, metallic objects can be placed on a floor plan so as to
obtain similar radio frequency channel effects. The environment created using the fractal approach was used to estimate the amount of energy a harvesting device can accumulate
in a University machine workshop space
Coupled dipole antennas for on/off-body communications at 2.45 GHz
In this paper, three experiments with coupled dipoles were carried out in order to determine the optimal distance where an efficient communication link can be established. The simulations results showed that when the subcutaneous dipole is installed adjacently to the surface of the skin, the dipole mounted above the skin level should be in the range of 20 mm to 25 mm for efficient communication. Subsequently, the influence of the
dielectric parameters of the human tissue on wave propagation has also been presented in this work
Delay spread emulation in machine workshops with fractals for wireless communication system planning
This paper presents a new way to estimate delay spread in machine workspaces by using fractal
geometry. In this way, inventories can be created quickly and used within a ray tracing software
to estimate the radio environment of machine workspaces as part of the planning process. Delay
spread is an important metric in assessing the performance of wireless technologies. Predicted 5G
cyber-physical systems in workplaces will require high-density use of wirelessly connected machineto-machine RF modules. In workshops, the surfaces and edges of machines, shelves, and furniture
influence the multipath/power delay profile of the space. However, with the fast construction pace and
high occupancy of buildings, it is impractical to characterise the location as building work progresses.
Consequently, it becomes more probable that the radio communication system deployed will perform
suboptimally. In this work, the Wi-Fi band was investigated. In addition, representative simulations were
also carried out at millimetre wave frequencies of 28 GHz and 60 GHz
RF power density measurements for RF energy harvesting in automobile factories
This paper presents RF power density measure-
ments carried out at an automobile manufacturing plant in the UK. This measurement campaign was carried out in order
to quantify the amount of ambient RF power available within the plant. Due to the location of the plant, low power density
measurements were recorded in the base-station downlink. The dominant frequencies at the plant were GSM-1800 and 3G. Average input RF power density for horizontal and vertical polarizations showed few variations in amplitude compared to
the maximum hold technique for the frequency band surveyed. The measurement campaign showed that at some locations at the plant, the input RF power density for 3G mobile transmit band was more than the base-station downlink