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Mobile Computing COE 446 Network Operation

Mobile Computing COE 446 Network Operation. Tarek Sheltami KFUPM CCSE COE http://faculty.kfupm.edu.sa/coe/tarek/coe446.htm. Principles of Wireless Networks K. Pahlavan and P. Krishnamurth. Outline. Handoff Management Architectural Issues in Handoff Handoff Decision Time Algorithms

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Mobile Computing COE 446 Network Operation

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  1. Mobile Computing COE 446Network Operation Tarek Sheltami KFUPM CCSE COE http://faculty.kfupm.edu.sa/coe/tarek/coe446.htm Principles of Wireless Networks K. Pahlavan and P. Krishnamurth

  2. Outline • Handoff Management • Architectural Issues in Handoff • Handoff Decision Time Algorithms • Types of Handoffs

  3. Mobile Management Handoff Management • Architectural Issues in Handoff • Set of protocols to notify all related entities of a particular connection that a handoff has been executed and the connection has to be redefined • In voice network, MT selects the BS that is serving its location • When an MT moves from one point of attachment to another, the old serving point of attachment has to be informed about the change (dissociation) • Other network components involved in routing mechanism have to be aware of the handoff in order to seamlessly continue the ongoing connection of the call

  4. Mobile Management • Handoff are classified according to the connection creation • Seamless handoff and hard handoff • Handoffs are classified into: • Network Controlled Handoff (NCHO) • Mobile Controlled Handoff (MCHO) • Mobile Assisted Handoff (MAHO)

  5. (Cellular Digital Packet Data)

  6. Mobile Management Handoff Management • Handoff Decision Time Algorithms • Traditional handoff algorithms are based on the RSS. Some of them are as follows: • RSS • RSS plus Threshold • RSS plus Hysteresis • RSS, Hysteresis and Threshold • Algorithms plus Dwell Timer

  7. Example • A mobile terminal is receiving signals from 3 BSs at the handoff region. • The handoff decision is made at each sampling time according to the below • table. The MT is initially connected with BS1. • Show the handoff transitions between BSs for each of the following • algorithms: • RSS • RSS + -60 dBm Threshold • RSS + Hysteresis 10 dBm • RSS + Hsyteresis 5 dBm + -55 dBm Threshold

  8. Mobile Management Handoff Management • Handoff Decision Time Algorithms • The performance of handoff algorithms measures have been considered such as call blocking probability, handoff blocking probability, delay between handoff request and execution, and call dropping probability • Handoff rate is related to the ping-pong effect and algorithms are designed to minimize the number of unnecessary handoffs

  9. Mobile Management Generic Handoff Management Process • Handoff decision is made and initiated • MT register with new visiting database via handoff messages • New visiting database communicates with the home database to get the subscriber profile and for authentication • Home database responds to the new visiting database with authentication of the MT • Home database sends messages to the old visiting database to cancel registration • The old visiting database flushes or redirects to the new visiting database and removes the MT from its list

  10. Mobile Management Handoff Management • Types of Handoffs: • Intracell, two channels • Intercellintradomain handoff, between two BSs associated with the same database • Intercellinterdomain handoff, between two BSs with different database

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