# Joint Optimization of Relay Communication Rates in Clustered Drones under Interference Conditions
## 5 Joint Optimization Scheme for Communication Rate
### Optimization of Power Allocation Factor for Cluster Drones
Therefore, this paper mainly considers the significant impact of transmission delay on the total communication delay. Assuming the total amount of data to be transmitted is 50 Gbit, Figure 14 compares the communication delays of the different schemes. As shown in the figure, the proposed scheme exhibited excellent delay performance during both the initial optimization phase and the stable optimization phase, reducing communication delay by 47.68%, 49.04%, and 49.78% compared to other schemes. Figure 15 illustrates the changes in the modulation order of the relay drone during the iterative process of joint optimization. As seen in the graph, with the progression of the task cycle and while meeting the bit error rate requirements, the choice of relay drone modulation order shifts from 16 to 4, then gradually changes from 64 to 16, and, finally, stabilizes with 64 occurring 88% of the time and 16 occurring 12% of the time. Figure 16 shows the changes in the transmission power of the relay drone over iterations. Since the trajectory of the cluster drones varies during the task cycle, the transmission power of the relay drone needs to compensate for the signal-to-noise ratio differences caused by the spatial displacement between the two. As the trajectory of the cluster drones follows a circular pattern, the transmission power level exhibits an oscillatory behavior, aligning with the changes in the scenario. Figure 4:1 Comparison of total communication rate values among different optimization schemes. Figure 4:2 Variation in the transmission power of the relay drone. Figure 4:3 Communication delay under different optimization schemes. Figure 4:4 Changes in the modulation order of the relay drone. Figure 17 illustrates the energy consumption variations in the relay drone during the mission execution period. As shown in the figure, with the continuous advancement of the mission, the drone needs to adjust physical variables such as trajectory and transmission power to adapt to the highest signal-to-noise ratio for information transmission. Consequently, throughout the mission period, there is a linear increase in flight energy consumption, total energy consumption per iteration, and total energy consumption when the relay drone operates at full power. Figure 18 shows the energy consumption of the relay drone during the mission. As seen in the figure, flight energy consumption constitutes the major portion of the total energy consumption. After optimization, the total energy consumption of the relay drone at a stable transmission power is 0.61% lower compared to operating at full power. Additionally, the total energy consumption required to complete the mission accounts for 70.89% of the system's stored energy. Figure 19 shows the changes in the three-dimensional trajectory of the relay drone. Initially, the relay drone's trajectory is a straight line. As the number of iterations increases,

Figure 4:5 Energy consumption variation in the relay drone during the mission period. Figure 4:6 Mission energy consumption value of the relay drone. the relay drone adjusts its path to balance the maximization of the signal-to-noise ratio across two-hop links, curving from the starting point to the termination point. The trajectory is smooth, without any interruptions, facilitating a stable communication link between the two hops. For the power allocation issue of cluster drones, given the significant spacing between the drone formations, substantial channel variations can occur among individual drones. Additionally, each subcarrier transmits data from two different drones. The relay drone can effectively distinguish the power levels of different cluster drones during serial interference cancellation. Therefore, throughout the entire mission cycle, the cluster drones can operate at full power for transmitting information. Figure 20 illustrates the impact of variables across different dimensions on the total communication rate.