A simple question: what is the name of concept that, for example, Google Maps and Waze use to discover and indicate traffic jam? Is that from users information or something with satellite signals?
There are usually various sources involved and it all depends on which product you're looking at. I might miss a source or two, but these are probably the most important ones:
Location data from mobile phones in the background: Google has its location services in Android that show Google where you are every once in a while. If several people are moving slowly while on a road, it's very likely they are in a traffic jam.
Location data actively shared via mobile phones: Waze is very open about doing this, for example. Whenever you have Waze open, your location is sent to their servers and if several people are slowing down at a certain location, the system assumes there is a traffic jam at that point.
Location data from service providers: many service providers give out aggregated detailed information on where their users are located. This data can be used to estimate how many people are at a manifestation, for example, but also to figure out where traffic is slowing down.
TMC (Traffic Message Channel) via radio: a digital layer (RDS) within the radio signal makes it possible for a traffic management agency to send out alerts for traffic jams, accidents, dangerous weather and so on. This is usually the only source used by built-in navigation systems.
Traffic data from road-side equipment: many countries have a monitoring system for their road network that allows them to see how many vehicles are passing at a certain point and at what speed. This data is sometimes shared by the government with other companies.
Usually the best solution is to use a combination of these sources. Navigation systems usually can't rely on just mobile phone data as they'd need a widespread use before it is possible to detect most traffic jams. Some sources require a lot of fine-tuning and complex algorithms to remove the noise in the data.