Joint Fairness and Efficiency Optimization for CSMA/CA-Based Multi-User MIMO UAV Ad Hoc Networks

Since conventional multiple access schemes, such as time division multiple access (TDMA), frequency division multiple access (FDMA), et al., cannot meet the requirements on flexibility, throughput and access delay in large-scale flying ad hoc networks (FANETs), we propose a fair and efficient CSMA/CA-based MAC protocol to facilitate concurrent uplink transmissions from different unmanned aerial vehicles (UAVs) by leveraging multiple-user MIMO (MU-MIMO). In this paper, we first propose the MIMO-based integrated sensing and backscatter communication model to achieve address resolution and also realize channel estimation by leveraging maximum likelihood estimation. Next, we propose an analytical model to characterize the saturation throughput and mean access delay of this CSMA/CA-based MAC protocol operating in an MU-MIMO FANET. Moreover, we derive the accurate expressions of saturation throughput and access delay under the proposed model. By means of the developed model, we evaluate the saturation throughput and access delay performance with respect to different network parameters, including the total payload, the number of UAVs and the number of UAV receiver's antennas. Numerical results indicate that our proposed protocol achieves superior throughput and decreased access delay.