Potential sharing between DTT and IoT services in the UHF band

Internet of things (IoT) will offer a new and revolutionary way to connect objects and/or devices to improve the day to day lives of citizens around the world. International Telecommunications Union (ITU) estimates that 25 billion devices will be connected to the internet by 2020. Nowadays, new research being carried out to define the technology and frequency bands for IoT. Narrow band LTE (NB-LTE) and the Ultra High Frequency (UHF) band could be an interesting solution for deployment of IoT. In this paper we propose the use of white spaces in the Digital Terrestrial Television (DTT) band (TV-White-Spaces) for spectrum sharing between DTT and IoT technologies. The scenarios consider a Digital Video Broadcasting-Terrestrial 2 (DVB-T2) network offering fixed rooftop reception as a primary service, and a NB-LTE network as a secondary service. The results have been obtained by laboratory measurements using professional equipment. We analyse the effect of the duty cycle on protection ratios, as well as peak rate and battery life for IoT devices. Our results provide the technical restrictions for the IoT NB-LTE node and devices, mainly on the maximum allowable Effective Isotropic Radiated Power (EIRP) that could transmit on the DTT band in terms of carrier separation, from co-channel and adjacent channel.