Evaluating the Potential of Spectrum Sharing in the Land Mobile Radio (LMR) Band

Abstract

In this paper we evaluate the potential for spectrum sharing in the Industrial/Business (IB) pool of the Land Mobile Radio (LMR) band. This study is based on measurements in the LMR band of both IB pool and Public Safety (PS) pool channels. Our experimental setup consists of two measurement stations located in a major metropolitan area using energy detection sensing. The analysis involves combining measurement data with license data publicly available from the FCC.Long term measurements show that even with significant geographic sharing, the spectrum in the IB pool is underutilized. Based on measurements collected throughout 2018 and 2019, we have observed diurnal and seasonal patterns in the use of LMR channels, showing that occupancy level changes can be attributed to factors such as business hours-of-operation, seasonal variation, and major events. Therefore, those channels have the potential for temporal spectrum sharing due to predictable patterns-of-use. In this paper we present analysis of occupancy in the LMR bands for both IB and PS pools. Occupancy graphs demonstrate usage patterns occupancy changes in the LMR band (both IB and PS) Chicago since a citywide stay-at-home order issued in March 2020. The LMR band has the potential to provide an additional layer of connectivity and redundancy for voice and data applications. In the wake of the COVID19 pandemic, there are challenges that could be addressed with additional spectrum, ranging from the need for healthcare facilities being able to effectively coordinate efforts to students who do not have adequate broadband to access educational resources from home during this crisis. Since the spectrum is underutilized, it is worthwhile investigating sharing, and applications that sharing could facilitate.