Joint Downlink Spectrum Allocation and User Association for Satellite-Terrestrial Integrated Networks

Abstract

In the satellite-terrestrial integrated networks (STINs), where a satellite access network cooperating with terrestrial network provides seamless coverage for ground users. However, severe co-channel interference may be inevitable, due to the spectrum sharing among these closely interrelated heterogeneous networks. Meanwhile, the satellite-user links always suffer larger attenuation compared to the terrestrial communications, which will aggravate the difference between two networks, such as data rate. In this paper, a dynamic spectrum partitioning strategy is used to reduce the inter-layer interference, and the user's maximum rate constraint is adopted to avoid any user monopolizing too many subchannels in terrestrial network. We aim to jointly optimization the downlink spectrum allocation and user association to maximize the total sum rate taking into account interference mitigation and user fairness. The optimization problem is then decomposed into two subproblems: resource allocation for terrestrial communications and satellite communications, which are solved by the heuristic algorithm separately. Finally, simulation results show the effectiveness of our proposed scheme in terms of total sum rate, maintaining a well-performed balance between system capacity and user fairness.