# Assessing the Capacity and Coverage of Satellite IoT for Developing Countries Using a CubeSat
## 4 Results and Discussion  
For estimating the coverage and capacity of a satellite in the ISS orbit to provide services to 11 mostly developing countries, Equation (1) was used, the parameters for which were derived in Section 3. In summary, the parameters that were obtained for the estimate are detailed in Table 7.  
The parameters are based on the ground test results, simulations and on-orbit results for the designed SIoT payload board and the GST design. The parameters include the antenna radiation pattern for both the satellite monopole antenna and the GST antenna, the sensitivity tests that were performed for the integrated satellite inclusive of all the EMI noises generated by the satellite subsystems, and the link budget calculation inclusive of the losses. The capacity of the system per day is summarized in Table 8 for scenarios considering the average of all satellite elevations simulated for a month and the duration of satellite to GST communication during this period. For the maximum capacity estimation, the simulation yielded a total of 22 satellite passes in a day with average elevation of 56 degrees and for minimum, a total of 12 passes with average elevation of 55 degrees were derived. The minimum amount of data per GST that can be received by the satellite per day is 45.50 kB. Although the estimation is based on the known system inference, it is still optimistic speculating other factors that could affect the performance of the receiver, such as impact of temperature on the receiver capability and the Doppler effect. Therefore, the efficiency factor is introduced in the equation that incorporates the efficiency due to temperature impact and the Doppler-effect mitigation method. Since the temperature on orbit depends on the beta angle of the satellite that varies between 0-74 degrees absolute values, the simulated beta angles with a threshold of 25 degrees for a period of one year are used to estimate the average capacity of the SIoT mission for a year in Table 9. \begin{table}
\begin{tabular}{c c} \hline \hline
**Parameter** & **Value** \\ \hline Satellite orbit altitude (km) & 400 \\ Orbital inclination (degree) & 51 \\ Number of satellites in orbit & 1 \\ Number of GSTs on the ground & 11 \\ Average satellite elevation per day (deg) & 56 \\ Average satellite pass time (min) & 4 \\ Average number of GSTs visible per day & 16 \\ \hline \hline \end{tabular}
\end{table} 
Table 7: Parameters for estimation of average SIoT capacity. \begin{table}
\begin{tabular}{c c c c c} \hline \hline \multirow{2}{*}{**Communication Time**} & \multicolumn{2}{c}{**Short Format**} & \multicolumn{2}{c}{**Long Format**} \\ \cline{2-5}  & **Per Day** & **Per Year** & **Per Day** & **Per Year** \\ \hline Minimum & 45.50 kB & 16.04 MB & 52.50 kB & 18.71 MB \\ Average & 60.50 kB & 21.39 MB & 70.00 kB & 24.95 MB \\ Maximum & 82.50 kB & 29.41 MB & 96.25 kB & 34.31 MB \\ \hline \hline \end{tabular}
\end{table} 
Table 8: Summary of SIoT capacity estimation for one year. The measured environmental parameters in most participating GST Network countries include temperature, humidity, and pressure. Considering at least two decimal digit resolutions for each sensor and assigning 4 bytes for each sensor, 31.79 kB of data in a day and 1.99 kB of data per pass, which is approximately 169 samples, can be collected from each country per day. This data capacity can be divided between multiple GSTs on the ground. In typical applications, the parameters for LoRa modulation such as the SF, CR and bandwidth can affect the amount of data that can be collected from the sensor terminals. Since the receivers are set to receive only five packets of data per minute, reconfiguration of these parameters allows for improving the quality of data packets that shall be received and not increase the upper limit of the capacity.