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Difference between revisions of "Mesh/Terms"
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https://en.wikipedia.org/wiki/Fresnal_zone | https://en.wikipedia.org/wiki/Fresnal_zone | ||
== Multiplexing == | |||
[http://en.wikipedia.org/wiki/Multiplexing Multiplexing] is the process of carrying multiple different signals over a shared medium. If multiple nodes are to share a limited number of paths between them, they have to figure out how to send them in a way that does not interfere with each other's signals. A variety of methods allow concurrent connections to be maintained between multiple nodes sharing a single line. Multiplexing techniques allow for better efficiency of bandwidth usage with a minimum of signal collisions. | |||
[[File:Multipexing demultiplexing scheme.png|thumb|The nodes in the network have their own slow lines which connect them to a multiplexing device. From there, the signals are sent over a fast line using a multiplexing technique. At the second multiplexing device, the signal is de-multiplexed so that the signals can be individuated and sent to their respective recipients.]] | |||
== TDMA == | |||
Time Division Multiple Access is a form of time division multiplexing. In time division multiplexing, connections are divided into specific temporal frames. Each individual connection is then assigned some fraction of the frame. Assume node A and node B are attempting to talk to eachother and node C and node D are also attempting to talk to eachother. If they are all within range of eachother and they try to communicate at once, they will interfere with eachother's signals. If instead, they pick a frame size of 100ms and divide that frame between the two connections, node A and node B can communicate within the first 50ms and then node C and node D can communicate within the second 50ms. This scheme is then scaled to incorporate many nodes. | |||
[[File:Tdma-frame-structure.png|thumb|A diagram showing TDMA time division multiplexing.]] | |||