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Radio frequency interference (RFI) constitutes a significant problem in achieving a good quality of service in radio links. Several techniques have been proposed to identify and mitigate RFI in wireless networks. However, most of these techniques are not generalized for all propagation environments due to varying geographical features from one environment to another. The need for extensive frequency scan measurements on the links to identify the available channels, evaluate the performances of the links, and detect RFI in the channels becomes imperative. This study presents a performance evaluation of frequency scan measurements from active microwave links comprising eighteen base stations. The measurements equipment included a spectrum analyzer and a 0.6 m antenna dish. The frequency scans were taken at 6 GHz, 7 GHz, and 8 GHz with full azimuth coverage of the horizontal and vertical polarization. Measured data were processed to determine the available frequencies and RFI in the channels. The histogram and probability density function of the frequency scans were computed. The cumulative distribution functions were determined, and the statistical error characteristics of the frequency scans for the estimated normal distribution and the estimated fitness curve were derived. The short-time Fourier transform of the noisy signal was obtained, and the signal without noise was recovered using the inverse short-time Fourier transform. Analysis of the scanned signals before and after the noise removal is demonstrated. The denoised signals compare favorably with related results in the preliminary literature. Overall, these frequency scans would be beneficial in evaluating RFI measurements and spectrum planning and hold great promise for designing robust RFI detection algorithms for future wireless systems.

One of the biggest challenges for wireless communication network operators is how to minimize or mitigate radio frequency interference (RFI) for efficient network services at the desired quality of service (QoS). Microwave radio links are highly susceptible to interference from narrow and wideband sources. Interference ultimately affects network quality and contributes to the colossal loss of usable mobile data, leading to substantial operational costs for network operators. Additionally, the implementation of high capacity microwave links could potentially force the channels to point towards the same direction, posing a significant interference source. Radio frequency interference issues on the microwave links should be prioritized for prompt resolution or mitigation to achieve the minimum QoS requirement for the growing network subscribers. Toward this end, frequency scans are required to accurately picture the available frequency plan and channels based on the allocated spectrum. This article presents experimental data on radio frequency interference of active microwave links at 6 GHz, 7 GHz, and 8 GHz. The extensive frequency scans were obtained from eighteen active base stations located in Kogi, Lagos, and Rivers States in Nigeria. The frequency scans were carried out using the Anritsu MS2724C spectrum analyzer and a 0.6-meter antenna dish with full azimuth coverage. The analyzer captures the horizontal and vertical polarization. The frequency scan measurements reported in this article would be significantly useful to radio frequency interference detection and mitigation, preliminary network equipment positioning, frequency selection and assignment, and microwave network planning.

Radio frequency interference (RFI) constitutes a significant problem in achieving a good quality of service in radio links. Several techniques have been proposed to identify and mitigate RFI in wireless networks. However, most of these techniques are not generalized for all propagation environments due to their varying geographical features. The need for extensive frequency scan measurements on the links to identify the available channels, evaluate the performances of the links, and detect RFI in the channels becomes imperative. In this study, performance evaluation of frequency scan measurements from active microwave links comprising eighteen base stations is presented. The measurements equipment comprises a spectrum analyzer and a 0.6-meter antenna dish. The frequency scans were taken at 6GHz, 7GHz, and 8GHz with full azimuth coverage of the horizontal and vertical polarization. Measured data were processed to determine the available frequencies and RFI in the channels. The histogram and probability density function of the frequency scans were computed. The cumulative distribution functions were determined, and the statistical error characteristics of the frequency scans for the estimated normal distribution and the estimated fitness curve were derived. The short-time Fourier transform of the noisy signal was obtained, and the signal without noise was recovered using the inverse short-time Fourier transform. Analysis of the scanned signals before and after the noise removal is demonstrated. The denoised signals compare favorably with related results in the preliminary literature. Overall, the frequency scans would be highly useful in evaluating RFI measurements and spectrum planning.

The introduction of electronic ballast in lighting systems design has dramatically revolutionized the lighting space. This is orchestrated by the entrance of the Compact Fluorescent Lamps (CFLs) and Light Emitting Diodes (LEDs) into the lighting market. The CFLs currently being used in domestic and industrial lighting systems provide highly competitive alternatives to conventional incandescent lamps. The electronic ballast incorporated into the CFLs helps eliminate the flickering and slow starting flaws prevalent in traditional fluorescent lamps. To properly evaluate the performance characteristics and limitations of the CFLs, a critical analysis of its electronic circuit becomes imperative. To this end, this paper presents experimental and simulation analyses of the CFL circuits. To achieve this, two Futina CFL bulbs of 11W and 15W model YPZ220/11-BMSP RR/RDD and YPZ220/15-BMSP RR/RDD, respectively, were analyzed and experimentally verified. A function-based programming paradigm was applied to develop a graphical user interface (GUI) used for the circuits analyses. The GUI is designed using MATLAB graphical user interface development environment (GUIDE). Experiments were conducted to obtain the performance characteristics of the CFLs, and measurements show that the 11W lamp has a higher amplitude than the 15W lamp. However, both lamps show similar waveforms after 300 seconds. The maximum voltage amplitudes for both CFLs are the same, with a peak value of 218V. The current waveforms in the spectral domain gave a maximum amplitude of 0.3 A for the 11W CFL and 0.2 A for the 15W. The voltage frequency (0.00196) of both CFLs are the same, whereas the current frequencies are different. This indicates that the wattage of a CFL does not affect the frequency of its voltage waveform. The frequency of the 11W CFL current (0.00157) is higher than that of the 15W CFL current (0.00784). This implies that the higher the CFL wattage, the lower the frequency of its current waveform. Additionally, simulation results revealed that the key difference between the CFLs is the current total harmonic distortion (THDI), which increases with an increasing rated power of the CFL or the aggregation of a number of the smaller rated CFLs.