In a telecommunications network , the uplink [ ʌplɪŋk ] denotes the connection ( English link ) with the direction of data flow which, from the point of view of a terminal, goes in the direction of the telecommunications network. The opposite direction is called the downlink .
Occasionally the terms “forward direction” for the downlink and “backward direction” for the uplink are also used, in accordance with the flow analogy (see downstream / upstream ). The up link is used to up load (upload), so the data transfer in the direction of the telecommunications network, the down link , however the down load (download) from the telecommunications network.
Uses of terms
The term uplink in satellite communication describes the direction from the earth station to the satellite, as well as from a mobile terminal to the satellite.
The satellite operators usually operate the uplink stations to satellites. However, some users of satellite systems operate their own uplink stations in order to save the effort for the transmission to the uplink station of the satellite operator. There are also customers who use mobile uplink stations, e.g. B. for satellite reporting or satellite phone .
The uplink frequency is received in the satellite and converted to a different downlink frequency in order to be reflected back to earth. To the largest possible footprint ( " footprint ") with the smallest possible satellite dishes to ensure the signals from the satellite amplifies and depending on the satellite (rarely depending on transponder ), which must be located on a very specific part of the world in the field of view of the satellite , sent back.
In hierarchical telecommunications networks Uplink refers to the direction from the hierarchically lower to the hierarchically higher network element ( engl. Up = up).
Wireless communication systems
In a wireless communication system such as a cellular network or a WLAN , the uplink denotes the direction of transmission from the mobile station to the base station , while the downlink denotes the opposite direction. In the case of GSM , the uplink is the direction from the mobile station via the base station and base station controller to the switching network. From the mobile phone user's point of view, the uplink is thus the transmission channel .
User ports , to which end devices such as hosts , computers and printers are connected, can be differentiated from the uplink ports via which the next concentrator can be reached. Since the data of many user ports is passed on via only one or a few ( bundling , resiliency , spanning tree ) uplink ports, these are usually designed to be much more powerful. Since a network concentrator could be connected to each user port, the transition between user ports and uplink ports is fluid.
In the uplink port of a concentrator, the send and receive lines are interchanged compared to a user port. In modern devices, however, the ports are often equipped with a functionality called Auto Uplink (also known as Auto MDI-X ). These ports automatically recognize whether it is necessary to swap the send and receive lines, so separate uplink ports or the use of crossover cables are unnecessary.
- Web Archive: “Andreas Voigt: What are ... uplink frequencies? , in sbc-online.de " ( Memento from February 18, 2005 in the Internet Archive )
- Web Archive: “Andreas Voigt: What are actually ... uplink frequencies? , in sbc-online.de " ( Memento from February 18, 2005 in the Internet Archive )