Joint Interference Management and Traffic Offloading in Integrated Terrestrial and Non-Terrestrial Networks

The exponential growth of data traffic beyond the 5G era necessitates improved resource utilization for the integrated terrestrial and non-terrestrial networks (ITNTN). In this work, we consider a multi-user multiple input multiple output (MU-MIMO)-empowered 5G ITNTN network consisting of terrestrial 5G and multi-beam geostationary earth orbit (GEO) satellite-based gNBs and develop an interference management framework that allows multiple users to receive downlink data over the same resource blocks (RB) simultaneously. Our developed framework first employs a traffic offloading algorithm by leveraging the reference signal received power (RSRP) and celledge width criteria to offload traffic from terrestrial to NTN networks. Subsequently, we formulate the resultant interference management as a joint power allocation and user-RB scheduling optimization problem to maximize the network’s spectral efficiency. Since the joint optimization problem is NP-hard and computationally intractable, a fractional programming-based solution is developed to obtain sub-optimal yet efficient transmit power allocation and user scheduling at terrestrial and satellite gNBs. A realistic ITNTN simulator is developed for performance evaluation by considering 3GPP channel models, antenna gains, and 5G RB numerology in rural terrestrial-GEO coexistence scenarios. Extensive simulation results confirm the efficacy of the proposed framework in managing interference and improving resource utilization at 5G ITNTN networks.