## 4 Implementation
### GPSR_DA Algorithm
#### 4.1.2 Angle Calculation
\begin{table}
\begin{tabular}{l l} \hline \hline
**Parameters** & **Values (Units)** \\ \hline Simulation Area & 10 \(\times\) 10 km–40 \(\times\) 40 km \\ Number of Nodes & 16, 32, 48, 96 \\ Simulation Time & 600 s–1000 s \\ Data Channel Speed Rate & 2 Mbps \\ Control Channel Speed Rate & 96 Kbps \\ Data Channel Distance & 2–5 km \\ Control Channel Distance & 10–40 km \\ Node Moving Speed & 12 m/s \\ Services Flows & 5 Kbps–25 Kbps \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Experiments parameters of settings. a loss of data packets during position information reporting, and the delay in updating position information during the position-holding process leads to inaccurate destination node information at the source node, resulting in the dropping of some packets. However, compared to GPSR, which incurs additional packet loss due to re-sending probe packets to search for destination node positions, SD-GPSR experiences fewer packet losses. Figure 5d illustrates the trends of average end-to-end delay for the four routing methods with varying traffic loads. In the range of 5 Kbps to 10 Kbps, SD-MANET, GPSR, and SD-GPSR show a slight increase in average end-to-end delay. Once the traffic load exceeds 10 Kbps, all three routing methods experience a significant increase in average end-to-end delay. SD-GPSR exhibits the largest increase, primarily due to the higher computational load on the nodes, resulting in packets staying in buffers for longer durations. Additionally, as more data are forwarded, the occurrence of routing holes increases, requiring the controller to compute route paths, leading to additional delays. AODV's delay increases with the growth of traffic load and network load. However, as the traffic load increases, routes are dynamically established, resulting in a larger number of routing entries and more opportunities for data forwarding, thus leading to a relatively smoother increase in delay. #### 5.3.2 Impact of Scenario Scale

In this section, four different scenario scales will be simulated to analyze the impact of the four routing methods on network performance in different scenarios. The scenario

Figure 5: Comparison of the influence of four protocols on network performance with data service changes. scales are 16 nodes, 32 nodes, 48 nodes, and 96 nodes, with a constant traffic load of 20 Kbps and a simulation duration of 600 s.

_(a) Control overhead in different scenario scales_

Figure 6 compares the control overhead of the four routing methods in different scenario scales. From Figure 5(a), it is evident that the control overhead of all four routing methods increases as the scenario scale grows. AODV's control overhead exceeds 6000 Kbps in the 96-node scenario. This is mainly because the number of nodes in the scenario increases, leading to more neighbor nodes for each node and consequently increasing the number of hops required from the source node to the destination node. The increased number of broadcasting RREQ messages significantly contributes to the generation of control overhead. GPSR incurs substantial control overhead due to the broadcasting of one-hop beacons and location probe packets, which also increase with the scenario scale. In terms of control overhead between the control plane and the data plane, SD-GPSR exhibits a relatively gradual increase, while SD-MANET experiences a significant increase in control overhead with the increase in the number of nodes, as evident from Figure 5(b). SD-GPSR primarily incurs overhead from reporting node positions and obtaining destination node positions. On the other hand, SD-MANET needs to maintain the network topology, including reporting its own one-hop and two-hop neighbor information, resulting in a much larger overhead compared to SD-GPSR's position and neighbor information reporting. Additionally, SD-MANET constantly calculates route paths and issues flow tables during network operation, leading to higher overall control overhead compared to SD-GPSR.