# How to calculate data rate in ground to satellite communication

I want to calculate the data rate in uplink transmission from ground IoT device to satellite.

Is it possible to calculate it with traditional Shannon equation ?

where B is bandwidth , P is transmit power , g is channel power gain , N0 is noise power.


I am not sure how to set these parameter in the case that satellite is at 780km low-earth orbit.

How can I simulate it correctly ? Is there any suggestion ?

Thanks.

Before checking data rate you need to check whether there's enough signal power to start with.

Link budgets are the reasonable way to start, although in many more cases that one would bet on, the equipment is installed assuming that because the link is similar to other working links, everything is going to be ok, that hardly every is, but as long as enough signal power and BER low enough every one is going to be happy.

1.- This website

claims to be an Narrow Band IoT Link Calculator.

2.- These IEEE papers are related to your question

NB-IoT over Non-Terrestrial Networks: Link Budget Analysis

https://ieeexplore.ieee.org/document/9322419

LTE IoT link budget and coverage performance in practical deployments

https://ieeexplore.ieee.org/document/8292260

Do you have IEEE Explore access?

In one of these papers there's a preview table named 3pgg vs aligned link-budget assumptions, lots of assumptions.

3.- What are the link parameters you are working with?

4.- If you need a fast-forward speak to Harris

5.- IoT already 'piggy-backs' on other systems like 5G to be used on 'the last mile'.

I leave it to you to find out how it's encapsulated, but if 3GPP is already modulated to optical, reaching the outdoor unit up in the base station masts, to then go back to RF, sure the IoT can save the athmospheric loop by being inserted into already existing links : LEO preferably, but then Doppler and the choice of atennas may be an issue.

6.- From the Fraunhofer Institut for integrated circuits :

https://www.iis.fraunhofer.de/en/ff/kom/satkom/satellite_iot.html#14798672851467296872

QUOTE

"..Thus an IoT terminal operating in a LEO or HEO network requires both a waveform tailored for the specifics of this communication channel and a suitable antenna design.."

and

" .. For professional equipment and broadband applications, DVB-S2X is the latest in the DVB- series of satellite communication standards. For IoT applications, DVB-S2X provides unique advantages by supporting very low signal-to-noise ratio (VL-SNR) operation down to -10 dB and a low-overhead super-frame structure. Especially the DVB-S2X super-frame format 4 provides a flexible extension with VL-SNR payload header (PLH) tracking. This allows robust synchronization and signal decoding under variable channel conditions. Fraunhofer IIS was actively involved in the development, specification and validation of DVB-S2X. DVB-S2X solutions and IP are available at Fraunhofer IIS for specific markets, including IoT .."

END_OF_QUOTE

• Hi John, Thanks for providing so much information. Yes , I do have access to IEEE Explore , so I am okay to read the paper. Nov 25 at 9:32
• What are the link parameters you are working with? I do not fully understand all the terminology here , so I am not sure how to set all the parameter for calculating data rate in IoT to satellite transmission. I would like to assume that Bw = 50MHz , Power = 1W , central frequency = 3GHz. And I have no idea what is the proper value I can use for channel power gain & noise power base on the setup I just mentioned. Nov 25 at 9:57
• Hi Henry, what I was trying to say is : do you want the check whether IoT signal can reach LEO MEO GEO satellites? and then calculate IoT signal parameters to be sent from satellite to Earth? to be received as if the IoT were located on Earth and within range? Or would you consider to encapsulate the signal in for instance DVB-S2 as hinted in Fraunhofer's website, have the IoT signal transported up and down inside another signal, and then on Earth extract and radiate? The 2nd option requires work on designing receiver interface (DVB-S2 back to IoT) but solves right away the up-down segment. Nov 25 at 10:10
• or may be it's only about coding an off-the-shelf device, the 2nd option I mean. Nov 25 at 10:11
• AGI STK agi.com/missions/communications has upgraded their software to precisely calculate link budget parameters. I recommend you have a look because even in the demo version, you may be able to get useful parameters for your link budget. Nov 25 at 10:41

Thank you again for replying so much detail information and explanation.

I know that I need to make sure that my simulation scenario is capable of doing transmission between ground & satellite first , so I can calculate the data rate in that scenario.

I am trying to use the uplink budget calculator with the parameter in screenshot. (I took the parameter in NB-IoT over Non-Terrestrial Networks: Link Budget Analysis as a reference)

I calculate the free space path loss first (assume satellite is at 700km) , and there are still some parameters I do not know how to set (Miscellaneous Loss & Receiver Loss) and what the proper result of Received Power it should be to make the transmission possible between IoT to satellite ?