Multiplexing and Inverse Multiplexing

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Multiplexing and Inverse Multiplexing

• Mustafa Ashurex, Scott Hansen
• BA 479

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Overview
Multiplexing

• Multiplexing is sending multiple signals or
  streams of data on an information line at the
  same time in the form of a single, more complex
  signal and then separating the signals at the
  receiving end.

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Overview
Inverse Multiplexing

• Inverse Multiplexing is combining multiple low
  speed streams of data to form a single
  higher-speed data stream. The sending and
  receiving ends use an inverse multiplexer with
  one high speed input stream. 

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Analog Transmission
Frequency Division

• Each signal is assigned a different frequency
  (sub-channel) within the main channel

• A typical analog Internet connection via a
  twisted pair telephone line requires
  approximately three kilohertz (3 kHz) of
  bandwidth for accurate and reliable data
  transfer.
• Suppose a long-distance cable is available with a
  bandwidth allotment of three megahertz (3 MHz).
  This is 3,000 kHz, so in theory, it is possible
  to place 1,000 signals, each 3 kHz wide, into the
  long-distance channel.
• Each input signal is sent and received at maximum
  speed at all times
• For many connections, a lot of bandwidth is
  required

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Analog Transmission
Frequency Division
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Digital Transmission
Time Division

• Each data stream is put into a single signal by
  separating the signal into many segments, each
  with a very short duration. Each individual data
  stream is reassembled at the receiving end based
  on the timing.

• Flexible
• Careful engineering and implementation necessary
• Bandwidth can be wasted

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Digital Transmission

• Time Division

Assume that a 3,000-hertz tone is applied to each
of the six channels in the transmitter. Assume
also that the rotating switch turns fast enough
to sample, in turn, each of the six channels 2.4
times during each cycle of the 3,000-hertz tone.

The speed of rotation of the switch must then be
2.4 X 3,000 or 7,200 rotations per second. This
is the optimum sampling for a practical system.
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Digital Transmission

• Time Division

When the transmitter and receiver switches are
synchronized, the signals will be fed in the
proper sequence to the receiver channels. The
samples from transmitter channel one will be fed
to receiver channel one.
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Digital Transmission
Statistical Time Division

• Employs a buffer memory which temporarily stores
  the data during periods of peak traffic, allowing
  STDM to waste no high speed line time with
  inactive channels.

• Flexible
• Doesnt waste bandwidth
• Increased complexity

Demo
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Fiber Optic Transmission
Dense Wavelength Division

• Multiple signals are carried together as
  separate wavelengths of light

• Up to 80 (and theoretically more) separate
  wavelengths or channels of data can be
  multiplexed into a light stream transmitted on a
  single optical fiber
• In a system with each channel carrying 2.5 Gbps
  (billion bits per second), up to 200 billion bits
  can be delivered a second by the optical fiber
• Different data formats being transmitted at
  different data rates can be transmitted together.

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Fiber Optic Transmission
Dense Wavelength Division
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Inverse Multiplexing
Packet-level

• Performs multiplexing at the network layer using
  the MP or MPP protocol.
• One data packet is send over the first channel,
  the next is send over the second channel, and so
  on, until all the packets are distributed over
  all the available channels.
• The receiving end adjusts for network-induced
  delay and reassembles the data packets into their
  proper order.

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Inverse Multiplexing
Packet-level

• Used in Telecommuting applications
• Provides load balancing
• Allows Scalability

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Inverse Multiplexing
Circuit-level

• Performs multiplexing at the physical layer using
  the AIM and BONDING protocols.
• A data stream is sliced into portions, then the
  data steams are distributed over all the
  available circuits.
• The receiving end adjusts for network-induced
  delay and reassembles the data streams into their
  proper order.

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Inverse Multiplexing
Circuit-level

• Used in Applications that require transparent
  digital circuits
• videoconferencing
• bulk file transfer applications
• Allows Scalability

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Sources

• http//www.tpub.com/neets/book17/75h.htm
• http//www.webopedia.com/TERM/D/DWDM.htm
• http//www.fiber-optics.info/articles/dwdm.htm
• http//en.wikipedia.org/wiki/Wavelength_division_m
  ultiplexing
• http//en.wikipedia.org/wiki/Time-division_multipl
  exing
• http//www.atis.org/tg2k/_time-division_multiplexi
  ng.html
• http//telecom.tbi.net/mux1.html
• http//en.wikipedia.org/wiki/Frequency_division_mu
  ltiplexing
• http//www.its.bldrdoc.gov/fs-1037/dir-016/_2344.h
  tm
• http//www.answers.com/topic/frequency-division-mu
  ltiplexing