Jakub J. Koston Multiplexing

'''Communication Networks'''

Multiplexing

Multiplexing, in telecommunications and computer networks, is a method of sending multiple signals through a shared medium between to (or more) clients. The origin and purpose of the multiplexing method is to create a way of sending multiple data streams through a single channel between two users.

Time-Division Multiplexing (TDM)

TDM is a used method of transmitting the data streams by separating them out in time. In TDM the data stream is followed by a few bytes of data that make it sufficiently different than other data streams to know who the sender and receiver is and how long the time-division must be before the next data stream may be sent. If they are separated out quickly and without fault, the data stream from the sending end will be sent across the medium and received by the end user only and no other receiver.

Advantages

Advantages of TDM is that, if the clock frequency is high and there is no fault during transmission, the data will be evenly and fairly distributed across the users both sending and receiving as they each get the same amount of bandwidth for a time-slot. It’s also the fastest way of transmitting digital data due to it allowing the full bandwidth to a single user at a time.

Disadvantages

Disadvantages of TDM is that it is really limited to digital signals and analogue signals are too large and need conversion for transmission which is not possible for long voice messages because of the limited time-slots. TDM will not work or be incredibly faulty if the clock frequency needs to be fast and highly synchronised or the data streams will be mixed up.

Statistical Multiplexing

Statistical Multiplexing is a method of data stream transmission using a static link at the sending and receiving end and is an alternative to a fixed sharing links and medium. Instead of containing a set of bytes to allocate a time-slot, the statistical multiplexing method assigns the data stream details and sends it to the end of the medium that reads the address of the data and connects to the appropriate receiver.