WIRELESS AND MOBILE NETWORK ARCHITECTURES

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WIRELESS AND MOBILENETWORK ARCHITECTURES

• BY
• VENUGOPAL.A 2000A7PS082
• SANJAY KULHARI 2000B5C6794

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Basic Terminologies

• PCS-gtPersonal Communication Services
• MS-gtMobile Station
• BS-gtBase Station
• MSC-gtMobile Switching Centers
• PSTN-gtPublic Switched Telephone Network
• HLR-gtHome Location Register
• VLR-gtVisitor Location Register

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• HANDOFF
• The process of disconnection of the radio link
  between the MS and old BS and the establishment
  of a radio link with new BS.
• ROAMING
• Location tracking of the MS when it moves from
  one PCS to another to maintain the mobility
  services.

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Types of Handoffs

• Soft Handoff
• The MS can communicate with both the old and new
  BS simultaneously.
• Hard Handoff
• The mobile can communicate with only one AP at a
  time.

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Who makes the Handoff Decision?

• MCHO-gtMobile controlled Handoff
• MS monitors the signal initiates the handoff,
  used in DECT,PACS.
• NCHO-gtNetwork Controlled Handoff
• BS measures signal from MS, network initiates
  handoff, used in CT-2Plus,AMPS.
• MAHO-gtMobile Assisted Handoff
• MS provides data which the network uses to make
  the decision, used in GSM,IS-95 CDMA.

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Inter-BS Handoff

• Old new BS are connected to the same MSC.
• Used with MCHO strategy.
• When MS initiates the handoff, following
• actions are taken..

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What happens if there are insufficient Resources
at new AP?

• Non-Prioritized Scheme
• Handoffs are handled as new calls
• Handover is blocked Keep using the
  existing channel until either the
• call is over or
• link fails (or forced termination)

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Strategy II for Insufficient Resources

• To reduce forced Termination and improve call
  completion
• Reservation channel scheme
• Queuing priority scheme
• Sub-rating scheme

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Roaming Management

• Registration
• The process by which MS informs the system of
  its current location.
• Location Tracking
• The process during which the system locates the
  MS-when the network attempts to deliver a call to
  it.

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Call Delivery Procedure

• The call request is forwarded to the HLR to find
  the current VLR of the MS.HLR queries that VLR to
  get a routable address of the MS.
• The VLR returns the routable address to the
  originating switch through HLR.
• A trunk (voice circuit) is setup based on the
  routable address.

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THANK YOU