Latency Minimization in Terrestrial-Non-Terrestrial Integrated Network: Joint Association and Bandwidth Allocation Framework

Integrated terrestrial-non-terrestrial network (T-NTIN) has recently gained much attention owing to its wide service area, seamless connectivity and high network throughput. The non-terrestrial network comprising the low earth orbit (LEO) satellites can complement the terrestrial network when the terrestrial base stations are partially damaged or the network demand is overloaded. In this work, we study an integrated terrestrial-non-terrestrial network in which the aerial users (AUs) are served by the terrestrial base stations (TBs) or LEO satellite in the downlink. For the energy-constrained AUs, it is crucial to successfully receive the data service from either one of TBSs or LEO satellite in a short time so that their flying or hovering energy is saved. Here, each TBS is assumed to have the existing associated terrestrial users (TUs). Therefore, it is challenging to determine how to allocate the communication resources of the TBSs to the associating TUs and AUs without sacrificing the QoS of the existing TUs. To tackle these challenging problems, we propose a joint association and bandwidth allocation framework to minimize the total latency of the AUs with the consideration of the TBS’s communication resource limitation, LEO satellite’s backhaul capacity, and the QoS requirement of the existing terrestrial users (TUs). The evaluation results are conducted to verify the superior performance of the proposed framework.