Cost-effective design for the measurement of man-made noise in the HF band receiver

Abstract

In recent years, there has been an upsurge in portable wireless devices, increasing demand for wireless data, higher transmission rates and the ever-increasing use of electromagnetic radio frequency (RF) spectrum. This has led to a scarcity of spectrum resources, therefore, to actively monitor RF spectrum use and optimise current usage models, this paper presents a unique cost-effective approach to conduct spectrum monitoring. This paper will examine the feasibility of installing a cost-effective RF Man-Made Noise (MMN) monitoring station onto a moving vehicle. To cut down costs, the RF MMN monitoring station will comprise of commercial consumer-based products to build the prototype i.e. Software Defined Radio (SDR), a computer, and GPS that is intended to be installed on public transport. In utilizing public transport, the RF MMN monitoring system can opportunistically collect measurements while moving through a specific area. These measurements will provide valuable data about RF spectrum use over a larger area compared to a single location-based station approach. A model of the RF MMN monitoring station is simulated in MATLAB. The emphasis on simulation models is to optimize the sample rate of measurements and maximise the accuracy and sensitivity of this approach. The sample rate is optimised by considering the spatial distance travelled on public transport. This will reduce the need for extra processing and storage overhead. To optimise the accuracy and sensitivity, an investigation is conducted on the noise floor generated by the inherent (internal) electronic noise of the system and the vehicle electronics that the system is installed in. A hardware prototype was designed to demonstrate the feasibility of the system. A pilot test run was conducted, and the measurement is plotted on a scatter plot map. The recorded measurements serve as a tool for analysing RF MMN over the geographic area in which public transport frequently travels. The RF MMN measurement system will contribute to enhancing traditional Man-Made noise databases with the sensors moving around within public vehicles. This will assist in identifying the primary, secondary, and illegal users, confirm spectrum database accuracy and will assist in refining current propagation models within the RF band in which the samples were measured. The RF MMN monitoring system is possibly the new “eyes and ears” of the regulatory body to actively monitor spectrum use.