Characteristics of Interference in Licensed and Unlicensed Bands for Intelligent Spectrum Management

The exponential growth of IoT devices and the demand of smart devices for higher data rates has heightened the need for sharing and managing spectrum resources in cellular 5G/6G operating in licensed bands and Wi-Fi technologies operating in unlicensed bands. Intelligent spectrum management has emerged as a key concept in dynamic spectrum allocation. To understand the interference existing in the spectrum, researchers usually monitor the interference in a fixed location and either focus on the cellular band or Wi-Fi band. In this study, we conduct experiments for collecting real-time spectrum data in indoor and outdoor environments with a mobile receiver, the spectrum analyzer. For outdoor, we mount the spectrum analyzer on a car seat and drive on the selected route in an urban area. We put the analyzer on a cart and moved it around in the laboratory for indoor. The frequency of interest in this study is 1.9 - 2.5 GHz, including both licensed and unlicensed bands. Temporal and frequency domain behavior is compared between licensed and unlicensed bands. We first normalize and binarize the data with a threshold. Then we calculate the spectrum occupancy by counting how many consecutive ones. Based on our observation, the spectrum occupancy of the outdoor environment is more remarkable than the indoor environment. The interference in the licensed band shows more variations in the frequency domain than that in the unlicensed band. This study provides a better understanding of the interference behavior for different environments and frequency bands.