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Overview of Location Management for Current Cellular and PCS

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Overview of Location Management for Current Cellular and PCS : Table of Contents 1. PCS or Cellular Architecture 2. Location Management 2.1 ... – PowerPoint PPT presentation

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Title: Overview of Location Management for Current Cellular and PCS


1
Overview of Location Management for Current
Cellular and PCS
  • ??? ???

2
Table of Contents
  • 1. PCS or Cellular Architecture
  • 2. Location Management
  • 2.1 Location Registration
  • 2.2 Call Delivery
  • 3. Location Registration and Call Delivery
    Research
  • 3.1 Centralized Database Architectures
  • 3.2 Distributed Database Architectures
  • 4. Location Update and Terminal Paging Research
  • 4.1 Location Update Schemes
  • 4.2 Terminal Paging Schemes

3
1. PCS or Cellular Architecture
  • ? Two level data structure
  • - HLR (home location register) ?? ?
  • ??? ??? ??? ??
  • - VLR ( Visit location register) ???
  • ??? ???? MT? ??? ??
  • ? ??? ?? ??? base station (BS)
  • ? ??? ? ?? ??? ??? Mobile
  • Switching center (MSC) ??
  • ? Signal System 7(SS7) the protocol used
  • for signaling exchange
  • ? Signal Transfer Point (STP) Network?
  • routing? ???? call? routing ??
  • ? ??? ?? ???? ??

Figure 2 PCS ?? ??
4
2. Location management
  • ? Tracks and locates the MT for delivery of
    incoming calls
  • ? Two methods
  • 1) The Electronic and Telephone Industry
    Associations EIA/TIA
  • Interim Standard 41 (IS-41)
  • 2) The Global System for Mobile Communication
    Mobile Application Part
  • (GSM MAP)
  • ? Location registration (location update)
    querying and storing
  • information in location database when MT
    enters the new LA
  • ? Call delivery sending paging signals to
    locate the user within the
  • network when incoming call

5
Figure 1 Location management operation
6
2.1 Location Registration (cont.)
  • ? Location update Reporting MTs current
    location to the network
  • ? Location registration ??? ?? ????? database ?
    update
  • ? When a MT enters an LA
  • - In case of same VLR Updating only VLR
  • - In case of different VLR Requiring a
    number of extra steps

7
2.1 Location Registration
  • lt Location
    Registration Procedures gt
  • 1. MT transmits a location update message to the
    new BS
  • 2. The BS forwards the location update message to
    the MSC which launches a registration query to
    its associate VLR
  • 3. The VLR updates its record on the location of
    the MT and sends
  • a location registration message to the HLR
  • 4. The HLR authenticates the MT and records the
    ID of the new serving VLR of the MT and sends a
    registration acknowledgement message to the new
    VLR
  • 5. The HLR sends a registration cancellation
    message to the old VLR
  • 6. The old VLR removes the record of the MT
    returns a cancellation acknowledgement message
    to the HLR

8
Figure 3, 4
Figure 3Location Registration Procedures
Figure 4Call Delivery Procedures
9
2.2 Call Delivery (cont.)
  • ? Two major steps
  • - Determining the serving VLR of the called MT
  • - Locating the visiting cell of the called MT
  • ? Paging
  • - MT? ?? ?? ????? ??? MT? ??? ???? ??? ???
    cells?? polling signal? ??? ???? ??? ??? ???? ??
    ??

10
2.2 Call Delivery
  • lt Call Delivery
    Procedures gt
  • 1. The calling MT sends a call initiation signal
    to the serving MSC of the MT
  • through a nearby BS
  • 2. The MSC determines the address of the HLR of
    the called MT by global title
  • translation and sends a location request
    message to the HLR
  • 3. The HLR determines the serving VLR of the
    called MT and sends a route
  • request message to the VLR . This VLR then
    forwards the message to the MSC
  • serving the MT
  • 4. The MSC allocates a temporary identifier
    called temporary local directory
  • number (TLDN) to the MT and sends a reply to
    the HLR
  • 5. The HLR forwards this information to the MSC
    of the calling MT
  • 6. The calling MSC requests a call setup to the
    called MSC through the SS7
  • network

11
3. Location Registration and Call Delivery
Research
  • ? As the number of mobile subscribers keeps
    increasing, the volume of signaling traffic
    generated by location management is extremely
    high
  • ? Need Methods for reducing the signaling
    traffic
  • ? Two categories
  • 1) Schemes based on centralized database
    architectures inherited from the IS-41 standard
  • 2) Schemes based on distributed database
    architectures

12
3.1 Centralized Database Architectures (cont.)
  • 4.1.1 Dynamic Hierarchical Database Architecture
  • ? Based on that of the IS-41 standard with the
    addition of a
  • new level of database called directory
    registers (DRs)
  • ? ??? MT? ??? ??? ??? local pointer , direct
    remote , indirect remote ? ??? ??? pointer? ??.
  • ? DR? ?? ??? ??? ??? ?? MT?? ?? ????? location
    pointer configuration ? ?? ?? ??
  • ? Calling MT ??? DR? pointer? ?????? call
    delivery? ?? signaling overhead? ??
  • ? HLR? DR? ID? ?????? MT? ??? ? DR? pointer?
    ???? ??? location registration ?? signaling
    overhead? ??

13
3.1 Centralized Database Architectures (cont.)
  • 4.1.2 Per-User Location Caching
  • ? The volume of signaling and database access
    traffic for locating an MT can be reduced by
    maintaining a cache of location information at a
    nearby STP
  • ? MT? cache? ??? ? Under the same
    VLR ? hit
    Moved to another location ?
    miss

  • ? IS-41 call delivery scheme
  • MT? cache? ?? ? IS-41 call
    delivery scheme
  • ? miss ?? ??? ??? ?? ?? (T-threshold) ?? cached
    entries ? ???
  • 4.1.3 User Profile Replication
  • ? Local database ? user profiles? ?????? ? ??
    ? ??? HLR query ?? called MT? ?? ??
  • ? MT? ?? ??? ??? ?? MT? user profile? ?? ????
    ????? ?? ??? ?? signaling overhead? ???? ??

14
3.1 Centralized Database Architectures
  • 4.1.4 Pointer Forwarding
  • ? MT? ?? VLR ???? ??? ???? HLR? ?? ??? ???? ???
    ?? VLR?? ??? VLR? pointer? ??? ?????? reporting?
    ??
  • ? MT? locating ?? ???? delay? ?? pointer ??
    threshold ??
  • 4.1.5 Local Anchoring
  • ? MT? ??? VLR? local anchor ? ???? location
    registration? ?? signaling traffic? ??
  • ? Static local anchor ??? call arrival ??
    VLR? local anchor
  • ? Dynamic local anchor Mobility? call
    arrival? ???? local anchor ??

15
3.2 Distributed Database Architectures
  • 3.2.1 A Fully Distributed Registration Scheme
  • ? Organized as a tree with the root and leaves
  • ? ?? database?? update ? query ? ???? location
    registration, call delivery ??? ???? ??
  • 3.2.2 Partitioning
  • ? MT? ???? ???? location server? ??? ??
    partition
  • ? ?? partition ??? location registration ? ??
    ?? ??? signaling message ??? ??? ??

16
4. Location Update and Terminal Paging Research
  • ? ?? IS-41? ???
  • 1) ? LA?? ??? ??? ???? ?? location update?
    ???? signaling traffic ??
  • 2) LA? ??? ???? MT? ??? ??? ????? ??? ?? ???
    ?? ??? ???
  • 3) MT? mobility ? ?? ?? ?? ?? ????
  • 4) Call arrival? ?? LA?? ?? paging ???
    broadcasting traffic? ??
  • ? Location update ? paging? ???? ??
  • - MT? ????? ???? paging ??? ?? ? ??? location
    update ? ?? ??? ???? ??? location update ?? ???
    paging ??? ??.

17
4.1 Location Update Schemes (cont.)
  • 4.1.1 Static Location Update
  • ? MT? ??? LA? ??? ? ?? update???? network? MT?
    ?? ??? ??? ???? ?.
  • ? MT?? mobility? call arrival pattern ??? ????
    ?? ?? ??? location update ? ???? ?? ??? ??.
  • 4.1.2 Dynamic Location Update
  • ? ??? cell?? location update ?? ?? ??? ?? ???
    Threshold? ?? location update? ???? cell? ??
  • ? Time-based location update
  • - MT? ??? ?? ?? (?T) ? ?? ????? update.
  • - ??? ??? ?? MT?? ???? ??? ??? ??? ????
  • update, MT?? mobility ? ???? ???? ??? ?
    ?? Time Threshold
  • ???? ???

18
4.1 Location Update Schemes
  • ? Movement-based location update
  • - MT? cell ??? ?? ??? ??? ??? ??? update
  • - ? ?? cell ??? ?? ???? MT? ???? ???? update
    ?
  • ?? ??
  • ? Distance-based location update
  • - ??? ?? ???? ?? ??? ??? ????? ??? update
  • - ?? ??? ??? ??? ??? MT? ??? ? ?? ??? ??
  • ?? ??? MT?? ??? call arrival? ???? ??? ??

19
4.2 Terminal Paging Schemes
  • 4.2.1 Paging Under Delay Constraints
  • ? Network area? ???? MT? LA? ?? ??
    (probability)? ??? ???? ???? polling cost ?? ? ??
    ??? polling sequence
  • 4.2.2 Update Paging Under Delay Contraints
  • ? MT? ????? ???? ??? ?? ??? ?(threshold)??? ???
    ?? ??? ??? paging delay ??
  • ? ??? threshold distance? ???? ?? iterative
    algorithm ??
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