Analysis of radio frequency spectrum usage using cognitive radio

This paper presents the analysis of radio frequency (RF) spectrum usage using cognitive radio. The aim was to determine the unused spectrum frequency bands for efficiently utilization. A program was written to reuse a range of vacant frequency with different model element working together to produce a spectrum sensing in MATLAB/Simulink environment. The developed Simulink model was interfaced with a register transfer level - software defined radio, which measures the estimated noise power of the received signal over a given time and bandwidth. The threshold estimation performed generates a 1\0 output for decision and prediction. It was observed that some spectrum, identified as vacant frequency, were underutilized in FM station in Benin City. The result showed that when cognitive radio displays “1” output, which is decision H1, the channel is occupied and cannot be used by the cognitive radio for communication. Conversely, when “0” output (decision H0) is displayed, the channel is unoccupied. There is a gradual decrease in the probability of detection (Pd), when the probability of false alarm (Pfa) is increased from 1% to 5%. In the presence of higher Pfa, the Pd of the receiver maintains a high stability. Hence, the analysis finds the spectrum hole and identifies how it can be reuse

Performance evaluation of 2.4kVA grid-tie inverter

This paper is focused on experimenting the overall performance of a 2.4kVA direct solar power supply system. The overall aim is to implement a solar power supply system without a battery back-up in order to minimize cost. The objectives include measuring the performance of grid-tie inverter, determine its period of operation under load conditions, to make the use of batteries optional in solar power supply system and minimize initial cost of installation. Various tests (variable load, fixed load and no-load) were carried out for the purpose of analysis. A dual trace digital storage oscilloscope was used to monitor the output waveform of the inverter to observe possible harmonic distortion on the waveform. The inverter takes its input power directly from the solar modules (panels) through the maximum power point tracker (MPPT) charge controller. Each category of test was conducted for at least three days of different weather conditions, to determine how variation in the sun’s intensity (irradiance) affects the operation of the inverter and its output power. Test results show that the inverter performs its function during the day apart from the early hours in the morning and later in the evening of each day, and the loads were powered successfully during the period of test.  The output waveform as observed from the oscilloscope is not purely sinusoidal; it is rather a modified sine wave

Mobile Phone Technology in Banking System: Its Economic Effect

Abstract: Globally, various initiatives use the mobile phone to provide financial services to those with or without access to traditional banks. This paper outlined vividly the use of mobile phone in the banking industry, its economic implications, and in general a systematic look into the various forms of mobile banking with emphasis on the security measures that makes the whole process safe for adoption. The emergence of mobile banking technology systems has implications for the general discussions about mobile telephony in the developing world. Existing theory about the significance of mobile communications in the developing world has focused on voice and text messaging. Moreso, the emergence of mobile banking also underscores how, occasionally, innovations emerge from unexpected places and have the capability of reconfiguring the significance of a technology to its users, offering a way to lower the costs of moving money from place to place and opening a way to bring more users into contact with formal financial systems

An Innovative Technique in Switching Electrical Appliances: An Omni-Directional RF Remote Control Switch Mechanism

Remote control systems for electrical appliances over the years have adopted the infra-red mechanism where the user is expected to point the controller towards the appliance before operation. This requires the user not only to be in the line of sight of the appliance but in close proximity to the appliance. The technique presented in this study is an omni-directional remote control system, which utilizes a Radio Frequency (RF) transmitter and receiver system. The piezoelectric crystal oscillator used in the implementation of the system operates at a frequency of 84 1.1I-Iz. It is an especially accurate form of electronic oscillator. The modulated signal is transmitted to the receiver in the RF band. The receiver, incorporated into the appliances sends the signal to the logic nnit. Through, the help of timer and digital connter ICs the relays receive signals to switch the appliance on or off as required. An operational distance of 35 m was realized