# Worldwide Coverage Mobile Systems for
## 2 Satellites Constellations
### Design Parameters for Satellite Communications
On the other hand, LEO low-orbit satellites are the other extreme in terms of antenna size. Given that they use orbits of the order of 700 to 1400 km, the losses of free space produced are quantified around 30 dB, much less than those that occur in GEO satellites. The low latency is practically negligible, in most applications, and the antenna size is really small and it can be powered by a small-size solar panel according to the size of the satellite. In the case of MEO medium-orbit satellites, they have orbits between 10,000 and 12,000 km around Earth. The distance from Earth as compared to GEO satellites is quite less, the problems due to latency are not as relevant. A GEO satellite typically must have an antenna approximately 10 to 12 m in diameter to provide the necessary gain. The antenna required by a satellite would be less than 50 cm. With the necessary power requirements, it would be possible to make an exchange between antenna size and transmitted power, since the antennas required in the case of LEO satellites are very small. Regarding the receiving end, one of the most relevant parameters is the G/T ratio, which depends on both the antenna gain and the losses in the same typical mobile terminal, the EIRP requirement is 0.5 w. The G/T ratio must be see at least \(-25\) dB/K. If a higher power is required, no more than a higher receiver sensitivity to buy with the requirements before writing the signal to noise ratio. \begin{table}
\begin{tabular}{l l l l} \hline \hline
**Attributes** & **Example-1** & **Example-2** & **Example-3** \\ \hline Carrier Frequency & Around 1.5 or 2 GHz for & Around 20 GHz for DL; Around & Around 40 or 50 GHz \\  & both DL and UL & 30 GHz for UL & \\ \hline Duplexing & FDD & FDD & FDD \\ \hline Satellite architecture & Bent-pipe & Bent-pipe, On-Board Processing & Bent-pipe, On-Board Processing \\ \hline Typical satellite system positioning in the 5 G architecture & Access network & Backhaul network & Backhaul network \\ \hline Bit Energy to Noise & Up to 2 @ 10 MHz & Up to 2 @ 250 MHz & Up to 2 @ 1000 MHz \\ Density Ratio & & & \\ \hline Satellite Orbit & GEO, LEO & LEO, MEO, GEO & LEO, MEO, GEO \\ \hline UE Distribution & 100\% Outdoors & 100\% Outdoors & 100\% Outdoors \\ \hline UE Mobility & Fixed, Portable, Mobile & Fixed, Portable, Mobile & Fixed, Portable, Mobile \\ \hline \hline \end{tabular}
\end{table} 
Table 6: Satellite examples. \begin{table}
\begin{tabular}{l} \hline \hline
**Parameter** \\ \hline Transmit Power and Bit Energy \\ Effective Isotropic Radiated Power \\ Equivalent Noise Temperature \\ Carrier-to-Noise Density Ratio \\ Bit Energy to Noise Density Ratio \\ G/Te Ratio \\ Illumination Level and Power Flux Density \\ C/Ts Ratio \\ \hline \hline \end{tabular}
\end{table} 
Table 5: Satellite system parameters. Practical systems using GEO, MEO, and LEO satellites have similar requirements for EIRP and G/T, but the antennas are very different from those used in mobile devices, as well as the power ranges. Table 7 shows the various types of antennas use in the satellite space segment antennas for different earth coverage strategies in GEO satellites. Shaping the beam allows for decreasing the required Tx power but increasing the antennas complexity. In MEO and LEO satellites, it does not make sense shaping the space segment antennas' beam given they are continuously moving and they try to cover all ofthe visible area.