Spectrum sensing and detection of incumbent-UEs in secondary-LTE based aerial-terrestrial networks for disaster recovery

In a disaster recovery scenario, there is a need for the deployment of a supplementary communications infrastructure when the regular communications infrastructure is considered to be damaged and is temporarily unavailable. Hence, we consider such a supplementary network operating as secondary user of the spectrum, which opportunistically utilizes the same spectral band as the incumbent regular network until the incumbent comes alive. When the incumbent network comes alive, it is important to vacate the corresponding spectral bands without interfering with its communications. In our work, we consider both the secondary and incumbent networks as LTE networks where the secondary network has an aerial base station with low altitude platform. In this paper, we propose a method to perform spectrum sensing at the aerial eNodeB for the secondary LTE network in order to detect the incumbent user equipments on ground to avoid interfering with them. A novel approach is presented to perform this task considering the 3GPP-LTE uplink transmission specifications. Moreover, we consider the energy based spectrum sensing for detecting the incumbent users on the ground by the aerial eNodeB, and extensive simulation results are presented in a Rice fading environment for the detection and the false alarm probabilities.