A Link Distance Division Based Time Division Multiple Access Protocol for Directional Aeronautical Relay Networks

In directional aeronautical relay networks, the airplane relay explores the advantages of the directional antenna, in terms of long transmission distance, low transmission power, small interference range and so on, to help the ground nodes transmitting data. However, data transmission delay extension problem occurs when the distance of the transmission link extends, where the wireless signal transmission time approximates the data transmission time such that the wireless signal transmission time cannot be omitted. To address the data transmission delay extension problem, a link distance division based time division multiple access protocol, LDD-TDMA, is proposed in this paper. Different from the traditional TDMA protocol, where the time slots are equal and are determined by the longest transmission link, the length of the time slots are different and are determined by different transmission links. Furthermore, the concept of communication coverage ring is proposed where the nodes located in the same ring communicate with the relay utilizing the same time slot length. The relationships between the number of rings, the ring radius and the transmission range of the LDD-TDMA are modelled and derived as a closed formula, where the ring radius are optimized such that the gain is maximized. Simulation results show that LDD-TDMA outperforms TDMA by 13.37% when the transmission range is 200 km and the ring number is 4.