How does a one-way satellite system work and what are the key protocols used

Usually such a system is composed by...
- satellite receiver
- dialup connection

such a system is usually found in areas where there's no other way to
get broadband. Like rural areas where nearest phone switch is too far
(technically impossible to have ADSL service) or areas that phone
companies consider unprofitable (few customers and too expensive to
bring the service).

In such a situation, where you need to get broadband, you could
eventually consider to use satellite.

Internet is received by satellite and packets from your computer are
sent back using a conventional system (like a slow dialup phone).

satellite provide a lot of bandwidth but....

1) you are anyway tied to a conventional connection with the inherent costs
2) latency is to be espected as there's many steps not to mention
satellite distance (usually 36.000km about your head)

this isn't a very tech explanation but I hope it will help to get an
overview of the system

ciao ciao