# Development, Implementation and Evaluation of An Epidemic Communication System
## 3 Implementation Method for Epidemic Communication
### Evaluation of the Amount of Data That Can Be Sent  
The evaluation involves assessing the amount of data transmitted when the transmitting station passes through the communication range of the receiving station. While there are various routes for passing through the communication range, a simplified method was employed to calculate the average transmitted data volume within the communication range.  
As an evaluation model, it was assumed that wireless stations pass through the communication area in different linear routes, as illustrated in Figure 9. The passage routes are considered to be evenly spaced, and the average transmitted data volume during all  
Figure 8: Sequence of connection and data transmission procedures.  
Figure 7: Connection and transmission behavior within the communication range.  
passages is calculated. In this model, the closer a point is to the center of the communication range, the greater the transmitted data volume, while points closer to the outside of the communication area result in a lower transmitted data volume. Under these conditions, the average amount of data that the transmitting station can transmit was calculated using the following formula:  
\[r_{n}=R-n\Delta d\quad(n=0,1,2,\ldots,N) \tag{5}\] \[t_{n}=\frac{2\sqrt{R^{2}-r_{n}^{2}}}{v}\] (6) \[C_{n}=\frac{t_{n}b}{8}\] (7) \[C_{\text{ave}}=\frac{1}{N+1}\sum_{n=0}^{N}C_{n} \tag{8}\]  
where \(r_{n}\) denotes the radius of the communication range obtained in Section 3.1; we set \(r_{n}\) to 0.3 m. When the moving route of the transmitting station passing through the communication range varies by \(\Delta d\) at evenly spaced intervals, the time spent within the communication range and transferable transmitted data volume is calculated based on the transmission rate. Additionally, \(R\) denotes the distance from the center when approaching the center by \(\Delta d\). \(v\) is the moving speed of the drone. To determine the time \(t_{n}\) to pass within the communication range, we calculated the distance \(x_{n}\) through the communication area using the Pythagorean theorem. We attempted this \(n\) times and calculated the transmission time when approaching the center of the communication range \(t_{n}\), transmission rate used during communication \(b\), and amount of data that can be transferred at that time. Next, we determined the average amount of data \(C_{\text{ave}}\) using the amount of transmission data \(C_{n}\) that can be transferred on each route and number of times \(N\) (\(N=R/\Delta d\)) passed through the communication range.  
Figure 10 shows the amount of data transferred relative to the movement speed for each transmission rate. The legend of Figure 10 indicates the respective transmission rates, and the x-axis indicates the movement speed of the wireless station. We observed a significant decrease in the transferable data amount when the movement speed changed from 0.1 to 0.2 m/s. In this study, the drone was assumed to capture flower image data of 500 KB, and the amount of data to be transmitted increased each time it passed another wireless station holding data, requiring the ability to transfer up to approximately 10 MB of data. Considering interference waves from the surroundings, transmission at lower rates may occur. Therefore, a drone speed below 0.2 m/s was desirable. The speed of infection  
Figure 9: Model for calculating transferable data volume.  
(i.e., the rate of spread) of the entire system depends greatly on the number of drones and their speed of movement, but epidemic communication is originally based on a delay method called DTN. Although the physical transport speed (movement speed) of data is not important, a higher transmission rate is desirable when passing each other, increasing the amount of data that can be shared.