Wireless Protocol Performance

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• Wireless Protocol Performance
• Mid Term Presentation
• Is About To Begin

• please take a sit.

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• Wireless Protocol
• Performance

• Itai Novitarger
• David Haloni
• Instructed by Shay Auster
• Spring 2002

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Goals

• Design development of layer algorithms for
  wireless networks.
• Changing TDMA transmission\reception rates.
• Algorithms performance analysis, which includes
  the following
• I. Performance measurement tools development.
• II. Algorithm implementation.
• III. Run Analysis of simulations.
• OPNET simulation environment acquaintance.

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OPNET Work environment

• Powerful network simulation environment.
• Allows complex statistics collection.
• User friendly GUI.

Design Work environment

• Lots of Pencils Papers

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Data Source
Control Source
Fragmentation Layer
Packet Storing Queues
Physical Layer
MAC
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Data Source

• Operates as Source Destination
• Generates\Destroys Data messages.
• Poison generation rate.
• Updates statistics.

Control Source

• Operate as Source Destination.
• Generates\Destroys Control messages.
• Poison generation rate.
• Updates statistics.

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Fragmentation layer

• Adjusts messages to a changing
  transmission\reception rate
• Disassembles messages arriving from the source
  into packets.
• Reconstructs the message fragments (packets)
  arriving from the network.

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Packet Storing Queues

• A set of bidirectional (In\Out) queues.
• Each queue stores both Data ctrl packets.
• Different queues contains packets designated for
  different transmission rates or received in
  different reception rates.
• Performs as buffers for both Fragmentation MAC
  layers.

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MAC Physical layers

• Implemented as a version of TDMA protocol.
• Supports changing transmission\reception rates
• Sorts, by reception rates, packets received from
  the network into the appropriate storing queue.
• De-queues a packet from the appropriate queue,
  according to transmission rates, and transmits it
  through the network.

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A little about TDMA

• Digital transmission technology
• Allocates unique time slots to each user within
  each channel.
• Allows a number of users to access a single
  radio-frequency channel without interference.
• Main advantages
• Offers the ability to support 64 kbps to 120 Mbps
  data transmission rates hence, enables operators
  to offer personal communication.
• Ensures that the users will not suffer
  interference from other simultaneous
  transmissions.
• Provides the user with extended battery life.

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TDMA WORKING METHOD

• Relies upon the fact that the audio signal has
  been digitized.
• Allocates a single frequency channel for a short
  time and then moves to another channel.
• Occupies different time slots in several bands at
  the same time from a single transmitter.

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Packets

• Two packet kinds
• Data Packet
• (Ethernet)
• Control Packet

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Performance Measurement

• Indicators set definition.
• For example
• Message transmission time The time interval
  starting at the sending of the first packet,
  ending at the arrival of the last packet.
• Time interval starting when the message is
  created, ending when the first packet is being
  treated.
• The affect of packet production rate (number of
  sources) over other indicators.
• Simulation in OPNET environment.
• Applying improvements.
• Final results presentation.

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Possible Approaches

• What happens if the transmission rate changes
  while a packet is being transmitted?
• Throw the packet away?
• Finish transmitting the packet?
• When is it possible for the fragmentation layer
  to start combining packets into a message?
• The node must receive all message fragments.
• Design implement internal and external packet
  numbering
• Add a Last bit in each every last packet.

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Future Developments

• Transmission\Reception rates determination
  algorithm.
• Currently rates changes according to an input
  file.
• Finite\Infinite storing queues.
• Currently Infinite queues.
• Priority queues.
• Making an effort to support convenient future
  expansions.

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Time Schedules
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Supplemental Information

• Mid Term Report
• http//www.comnet.technion.ac.il/cn6s02/Document
  s/Mid20Term20Report.doc
• Website
• http//www.Comnet.technion.ac.il/cn6s02/index.ht
  m

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Questions ???
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• FIN