Slotted ALOHA With Relay Control Scheme for Air-to-Ground Communications

This letter proposes a contention-based random access for air-to-ground communications, which is based on a slotted ALOHA protocol with a relay control scheme (RCS-ALOHA). In RCS-ALOHA, idle UAVs are exploited as relay UAVs. By encouraging relay operation with low transmit power, the proposed RCS-ALOHA increases the likelihood that distance UAVs will succeed. Each relay UAV is connected to some active UAVs and forwards information through fixed slots with scheduling. Next, a ground control station as the receiver implements iterative cancelation for the decoding process. The throughput of RCS-ALOHA is derived to validate the superiority of RCS-ALOHA over slotted ALOHA.