Feasibility of deploying wireless Internet of Things in the unlicensed European 865-868 MHz band

The European Commission has made the unlicensed 865-868MHz band available for deployment of wireless Internet of Things. The band is mainly used by RFID systems, but the current activity levels are unknown. In this paper, the in-band power levels are measured in five areas. The measurements show that RFID interrogators emit high-power single tone-like signals in four subbands, when active. Most signals are 0.4 s long, but it differs whether the subbands are used in a coordinated way or not. In some areas the RFID systems use a single subband about 80% of the time, while in other areas two to three subbands are occupied simultaneously 65-80% of the time. The measurements are used to evaluate the performance of a narrowband wireless Internet of Things technology, if it were to be deployed in the 865-868MHz band. Specifically, the measurements serve as interference input in a calculation of error rate probability. If the least interfered subband is always selected for the wireless Internet of Things transmission the error rate is 0%for desired signals up to −115 dBm, while if the subband with highest average interference is used, the error rate is up to 7.5% and at least 25% at −100 dBm and −120 dBm, respectively.