Location Management in PCS Networks

1. Location Management in PCS Networks Report of Dissertation By Manikanta Velaga (Adm. No. 612895) Sanjoy Mondal (Adm. No. 612920) M.Tech (CA)

2. Mobility Management • Mobility management has widely been recognized as one of the most important and challenging problems for a seamless access to wireless networks and mobile services. • Mobility management is the essential technology that supports roaming users with mobile terminals to enjoy their services through wireless networks when they are moving into a new service area.

3. From the viewpoint of functionality, mobility management mainly enables communication networks to • Locate roaming terminals in order to deliver data packets. • Maintain connections with terminals moving into new areas.

4. The two aspects in Mobility Management • Location Management • Handoff Management

5. Location Management • Location management equals locate roaming terminals in order to deliver data packets to them despite the fact that their locations may change from time to time. The essence of location management is constituted by the mechanisms for mapping the name of a mobile node to its address.

6. Handoff Management • Handoff management enables the network to maintain a user’s connection as the mobile terminal continues to move and change its access point to the network.

7. Location Management Operations • Location Registration • Location Paging

8. Location Registration • Location registration, also known as location update or tracking, that is the procedure that the mobile node informs the network and other nodes of its new location through special messages by updating the corresponding location information entries stored in some databases in the networks.

9. Location Paging • Location paging, also known as locating or searching. In most cases location information stored in databases is only the approximate position of a mobile device. Location paging is then the procedure that, when calls/ packets need to be delivered to the target mobile device, the network tries to find the mobile device's exact locality.

10. Types of Serving Networks • Internet or Intranet • Personal Communication Service Networks (PCS) • Mobile Adhoc Networks • Mix of the above networks

11. PCS Networks PCS Network is a Cellular Architecture

12. The coverage area is divided into Location Areas (LA) Location Area is divided into Cells.

13. It is a two tier architecture, a Home Location Register (HLR) and Visitor Location Register (VLR). • HLR: It contains the permanent data (e.g. directory number, profile information, current location and validation period) of the Mobile Terminals whose primary subscription is within the area. • VLR: It contains temporary record for all Mobile Terminals currently active within the Registration Area of the MSC

14. Objective To minimize: • the cost of Location Registration. • the cost of Location Paging • the cost of Call Delivery.

15. Literature Survey • A Forwarding Pointer–Based cache scheme for Reducing Location Management Cost in PCS networks.

16. A Dynamic HLR Location Management Scheme for PCS networks

17. IS-41 location registration scheme: • The MT detects that it has entered a new RA and sends a location update message to the new MSC through the base station. • The MSC updates its associated VLR indicating that the MT is residing in its area and sends a location registration message to the master HLR of the MT. • The message is routed to a STP which determines the master HLR of the called MT from its Mobile Identification Number (MIN) by a table lookup procedure called Global Title Translation (GTT) .The location message is then forwarded to the master HLR. • The master HLR updates its record indicating the current serving MSC of the MT and sends a registration acknowledgement message to the new MSC. • The master HLR sends a registration cancellation message to the old MSC. • The old MSC deletes the record of the MT in its associated VLR and sends a cancellation acknowledgment message to the master HLR.

18. The Location registration procedure under IS-41 standard

19. The existing call delivery scheme: • A call is initiated by an MT and the base station forwards the call initiation signal to the MSC. • The MSC sends a location request message to the master HLR of the called MT through a STP where GTT is performed. • The location request is forwarded to the master HLR. • The master HLR sends a location request message to the MSC serving the called MT. • The MSC determines the cell location of the called MT and assigns it a Temporary Location Directory Number (TLDN) .The MSC then sends this TLDN to the master HLR. • The master HLR forwards the TLDN to the calling MSC. • The calling MSC sets up a connection to the called MSC using this TLDN.

20. The call delivery procedure under IS-41 standard

21. Location registration under “Dynamic HLR Location management “ scheme as follows: • The MT detects that it has entered a new RA and sends a location update message to the associated new MSC through the base station. • The new MSC updates its associated VLR indicating that the MT is residing in its area and sends a location registration message to the STP in the signaling network. • The message is routed to the associate HLR of the new MSC trough the STP by the modified MSC-dependent GTT table lookup procedure. Note that the associate HLR is also the current (nearest) HLR for the MT. • The current HLR updates its record indicating the current serving (new) MSC of the MT and sends a registration acknowledgement message to the new MSC. If the MT stays in the same SA, proceed to the next step; otherwise (i.e, the MT moved into a new SA), go to step7. • The current HLR sends a registration cancellation message to the old MSC. • The old MSC deletes the record of the MT in its associate VLR and sends a cancellation acknowledgement message to the current HLR, stop.

22. 6. (For the case that the MT moved into a new SA)The new current HLR sends a message to the old current HLR informing the movement of the T. • The old current HLR sends its record about the MT to the new current HLR. It also sends a registration cancellation message to the old MSC. • The old MSC deletes the record of the MT in its associate VLR and sends a cancellation acknowledgement message to the old current HLR. • If the new current HLR is the master HLR, it just sends the old current HLR a registration acknowledgement message; other wise it sends both the old current HLR and the master HLR a registration acknowledgement message. • For the old HLR, if it is the master HLR, it updates its record pointing to the new current HLR; otherwise, it deletes the record of the MT. • For the master HLR, if it is the new current HLR, it does nothing; other wise, it updates its record pointing to the new current HLR.

23. location registration under “Dynamic HLR location management” scheme

24. The call delivery under “Dynamic HLR Location management” Scheme: • The proposed call delivery scheme is presented as follows • A call is initiated by an MT (caller) and the base station forwards the call initiated signal to the MSC. • The MSC sends a location request message to the associate HLR. If the caller is in the same SA, the associate HLR is used as the current HLR for the MT; other wise the existing GTT table lookup procedure is used to fine the master HLR of the called MT, and then to find the current HLR of the called MT. • The location request is forwarded to the current HLR of the called MT. • The current HLR sends a location request message to the MSC serving the called MT. • The MSC determines the cell location of the called MT and assigns it a Temporary Location Directory Number (TLDN) .The MSC then sends this TLDN to the current HLR. • The current HLR forwards the TLDN to the calling MSC. • The calling MSC sets up a connection to the called MSC using this TLDN.

25. The call delivery procedure under “Dynamic HLR Location management” scheme

27. Proposed Scheme To reduce the cost in the “Dynamic HLR location management in PCS networks”. That means the “Dynamic HLR location management in PCS networks “ method is taking extra cost for some cases like mobile terminal is moving in between some service areas frequently. For each movement in between two SAs the whole procedures have to implement again and again. That is waste of cost. So avoiding that cost I am proposing new idea which maintains cache information at each HLR

28. The Location registration under proposed “Pointer based HLR” scheme as follows • The MT detects that it has entered a new RA and sends a location update message to the associated new MSC through the base station. • The new MSC updates its associated VLR indicating that the MT is residing in its area and sends a location registration message to the STP in the signaling network. • The message is routed to the associate HLR of the new MSC through the STP by the modified MSC dependent GTT table lookup procedure. • The current HLR updates its record indicating the current serving (new) MSC of the MT and sends a registration acknowledgement message to the new MSC. • The new current HLR sends a message to the old current HLR informing the movement of the MT. • The new current HLR checks its corresponding CACHE, for an entry that corresponds to that particular MT. If it has found then the new current HLR immediately deletes that entry of MT from the corresponding CACHE. • The old current HLR sends a message to old MSC to update its associate VLR. And updates it’s HLR database indicating that the mobile terminal is currently not active in that SA. And make a pointer entry regarding the movement of MT in its corresponding CACHE. That entry tells the information to which HLR it has gone. • The old MSC deletes the record of the MT in its associate VLR and sends a cancellation acknowledgement message to the old HLR.

29. The Location registration under proposed “Pointer based HLR” scheme

30. call delivery procedure under proposed “Pointer based HLR” scheme as follows • A call is initiated by an MT0 and the base station forwards the call initiation signal to the MSC. • The MSC sends a location request message to the master HLR by using existing GTT table look up procedure. • The location request is forwarded to the current HLR of the called MT (that is MT1). • The current HLR sends a location request message to the MSC serving the called MT (that is MT1). • The MSC determines the cell location of the called MT and assigns it a Temporary Location Directory Number (TLDN). The MSC then sends this TLDN to the current HLR. • The current HLR forwards the TLDN to the calling MSC. • The calling MSC sets up a connection to the called MSC using this TLDN.

31. call delivery procedure under proposed “Pointer based HLR” scheme call delivery procedure under proposed “Pointer based HLR” scheme

32. Implementation Description of the System Hierarchical Network Structure

35. The following shows the example input to the system RESULTS

36. Initial state of all service areas

37. Example output

38. The state of all caches after target MT is moving

39. Final Output (Connection Establish Statements)

40. Analytical Model Notations used in the performance analysis • λ l , λA : the incoming call arrival rates (i.e., average number of incoming calls per unit of time) from the same SA where the called MT locates and from other SAs, respectively. • 1/ λ m: the average Registration Area(RA) residence time. • p: inter-SA movement probability. • Ch : cost for updating or querying the HLR. Cv : cost for updating or querying the VLR

41. • Cg: cost for performing the Global Title Translation (GTT) to determine the master HLR/Current HLR. • • C 1 and C2: signaling costs for the communication links in the same SA and between different two SAs, respectively. We also call C 1 and C2 intra-SA signaling cost and inter-SA signaling cost, respectively. • • N: number of SAs in the PCS network. Assume that the possibility that an MT resides in any SA is considered to be the same (i.e., 1/N).

42. Analysis of Location Registration method under “Dynamic HLR Location management” Scheme for when “a mobile is terminal moving among SAs” • The costs per unit time for location registration under the “Dynamic HLR location management” scheme as follows, CLR = λm{ p(4 C1+3C2+2Cv +3Ch)+ Cg }. For 11 service areas (N=11) CLR=10 λm{p(4C1+3C2+2Cv +3 Ch)+Cg }.

44. Analysis of Location Registration method under proposed “Pointer based HLR” Scheme for case when “a mobile terminal is moving among SAs” Total cost is C*LR=λm{p(5C1+C2+2Cv+2Ch+Ccacheop+ Ccachesearch)+Cg } For 11 service areas (N=11) C*LR =10*{5C1+C2+2Cv+2Ch+Cg+Ccacheop+Ccachesearch}

46. Analysis of Call delivery method under “Dynamic HLR Location management” Scheme for case when “a mobile terminal is moving among SAs” • The total costs per unit time for the call delivery under the “Dynamic HLR scheme” is obtained as CCD=λA (N-1)/N (3C1+3C2+2Cv+Ch+Cg).

48. Call delivery method under proposed “Pointer based HLR” Scheme for case when “a mobile terminal is moving among SAs” The total cost for call delivery is obtained as, CCD= λA(N-1)/N(3*C1+4*C2+Cg+2*Cv+2*Ch) +9*(Ccachesearch)

50. Performance comparisons