Mobile location management in ATM networks

• US 6,078,575 A
• Filed: 06/26/1997
• Issued: 06/20/2000
• Est. Priority Date: 10/01/1996
• Status: Expired due to Term

• Current Assignee: Lucent Technologies, Inc. (Nokia Corporation)
• Original Assignee: Lucent Technologies, Inc. (Nokia Corporation)
• Inventors: Dommety, Gopal Krishna, Veeraraghavan, Malathi
• Primary Examiner(s): Chan, Jason
• Assistant Examiner(s): BOAKYE, ALEXANDER O
• Application Number:
  US08/882,991
• Time in Patent Office: 1,090 Days
• Field of Search: 370/338, 370/256, 370/390, 370/395, 370/400, 370/407, 370/408, 455/432, 455/456, 455/435, 455/445
• US Class Current: 370/338
• CPC Class Codes: H04L 2012/5607 Radio
• CPC Class Codes: H04L 2012/5615 Network termination, e.g. NT1, NT2, PBX
• CPC Class Codes: H04L 2012/5619 Network Node Interface, e.g. tandem connections, transit switching
• CPC Class Codes: H04L 2012/563 Signalling, e.g. protocols, reference model
• CPC Class Codes: H04Q 11/0478 Provisions for broadband connections
• CPC Class Codes: H04W 8/04 Registration at HLR or HSS [Home Subscriber Server]
• CPC Class Codes: H04W 8/085 involving hierarchical organized mobility servers, e.g. hierarchical mobile IP [HMIP]
• CPC Class Codes: H04W 8/12 between location registers or mobility servers
• CPC Class Codes: H04W 80/04 Network layer protocols, e.g. mobile IP [Internet Protocol]

Abstract

The tracking of mobile terminals served by base stations supported by respective switches are formed into respective peer groups of switches in which the peer groups are then formed into a hierarchical logical network having a prescribed number of levels of scope S, and in which individual ones of the switches serve as a home switch for respective ones of said wireless terminals is enhanced. Specifically, responsive to receiving a registration message sent by one of the wireless terminals, the receiving switch notifies the home switch associated with the sending terminal. The home switch, in turn, notes the current location of that terminal and sends a similar message to the switch serving the zone in which the sending wireless terminal was last located. The latter switch, responsive to receipt of the message sets a pointer that points to (a) the current location of the sending wireless terminal if the switch is within the scope of the current location of the sending terminal or (b) the home switch if the switch is outside of the scope of the current location of the sending terminal.

Claims

1. A network comprising a plurality of switches, said switches being formed into respective peer groups, said peer groups being formed into a hierarchical logical network of L levels, where L≧

1, each of said switches being associated with a plurality of base stations each operative for communicating with wireless terminals located in respective cells, individual ones of said switches serving as a home switch for respective ones of said wireless terminals, said network further comprising

at one of said switches, responsive to receiving from an associated base station a registration message originating from one of said wireless terminals, generating a message containing information relating to the current location of said one of said wireless terminals and sending the message to the other switches that are within S levels of said one of said switches and to a switch previously serving said one of said wireless terminals,

at each of said other switches, responsive to receipt of said message, updating an associated reachability database to indicate the current location of said one of said wireless terminals, and

at said switch previously serving said one of said wireless terminals, responsive to receipt of said message, setting a pointer pointing to the current location of said one of said wireless terminals, and wherein if said one of said wireless terminals is not within scope S of said previous switch, then said previous switch responsive to receipt of said message, updates an associated reachability database to indicate that said one of said wireless terminals may be reached via a home switch associated with said one of said wireless terminals.

2. The network of claim 1 wherein said peer groups form a PNNI network.

3. The network of claim 1 wherein said previous switch sends the reachability update information to each of the switches that are within scope S of said previous switch, and wherein each switch that receives the update information then updates its own reachability database to indicate that said one of said wireless terminal may be reached via the home switch associated with said one of said wireless terminals.

7. The network of claim 1 further comprising at said one wireless terminal, responsive to generating said registration message, including an identity associated with said previous switch in said registration message and then sending the registration message over the air to a base station serving a zone in which said one wireless terminal is currently located.

8. The network of claim 1 further comprising

at said one switch, generating a message containing an identity of said one switch and sending the latter message to said one wireless terminal.

9. The network of claim 8 wherein the identity of said one switch is an Internet Protocol address.

10. The network of claim 1 wherein said network further comprises a plurality of routers forming a router network interconnected with individual ones of said switches and wherein said registration message is routed over said network via said router network.

17. The network of claim 1 further comprising

at another one of said switches, responsive to receiving a call request message for said one wireless terminal in which the call request message contains a dummy indicator, forwarding said request message to a next one of the switches identified as a function of the dummy indicator.

4. A network comprising a plurality of switches, said switches being formed into respective peer groups, said peer groups being formed into a hierarchical logical network of L levels, where L≧

1, each of said switches being associated with a plurality of base stations each operative for communicating with wireless terminals located in respective cells, individual ones of said switches serving as a home switch for respective ones of said wireless terminals said network further comprising

at one of said switches, responsive to receiving from an associated base station a registration message originating from one of said wireless terminals generating a message containing information relating to the current location of said one of said wireless terminals and sending the message to the other switches that are within S levels of said one of said switches and to a switch previously serving said one of said wireless terminals,

at each of said other switches, responsive to receipt of said message, updating an associated reachability database to indicate the current location of said one of said wireless terminals,

at said switch previously serving said one of said wireless terminals, responsive to receipt of said message, setting a pointer pointing to the current location of said one of said wireless terminals, wherein if said

one of said wireless terminals is not within scope S of said previous switch, then said previous switch, responsive to receipt of said message, updates an associated reachability database to indicate that said one of said wireless terminals may be reached via a home switch associated with said one of said wireless terminals, and

in said one switch, responsive to said home switch being outside of the scope of said one switch, sending said message to the home switch.

5. The network of claim 4 further comprising

in the home switch, responsive to receipt of said message, updating a forwarding pointer so that the forwarding pointer points to a neighborhood in which said one terminal is located, in which said neighborhood includes all of the switches within scope S of said one wireless terminal.

6. The network of claim 5 wherein said previous switch has an identity that is an Internet Protocol address.

22. The network of claim 5 wherein said previous switch has an identity that is an NSAP address.

11. A network comprising a plurality of switches, said switches being formed into respective peer groups, said peer groups being formed into a hierarchical logical network of L levels, where L≧

1, each of said switches being associated with a plurality of base stations each operative for communicating with wireless terminals located in respective cells, individual ones of said switches serving as a home switch for respective ones of said wireless terminals, said network further comprising

at one of said switches, responsive to receiving from an associated base station a registration message originating from one of said wireless terminals, generating a message containing information relating to the current location of said one of said wireless terminals and sending the message to the other switches that are within S levels of said one of said switches and to a switch previously serving said one of said wireless terminals,

at each of said other switches, responsive to receipt of said message, updating an associated reachability database to indicate the current location of said one of said wireless terminals,

at said switch previously serving said one of said wireless terminals, responsive to receipt of said message, setting a pointer pointing to the current location of said one of said wireless terminals, and

at another one of said switches, responsive to receiving a call for said one wireless terminal, reading from its associated database reachability information associated with said one wireless terminal and routing the call to said one wireless terminal as a function of the read reachability information.

12. The network of claim 11 further comprising

at a home switch associated with one wireless terminal, responsive to receiving said call, forwarding the call to said one of said switches in conjunction with sending an associated call set-up message to said one of said switches.

13. The network of claim 12 wherein said home switch inserts a dummy indicator in said call set-up to indicate the current location of said one wireless terminal.

14. The network of claim 11 further comprising

at said previous switch, responsive to receiving said call, forwarding the call to said one of said switches.

15. The network of claim 14 wherein said previous switch inserts a dummy indicator in said call set-up to indicate the current location of said one wireless terminal.

16. The network of claim 11 further comprising

at another one of said switches, responsive to receiving a call request message for said one wireless terminal forwarding said request message to a location identified in said reachability database for said one wireless terminal.

18. The network of claim 12 further comprising

in each of the switches forming a route from a first one of the switches receiving said call request message to a second one of the switches now serving the cell in which said one wireless terminal is now located, inserting its identity in a connection list in the request message when it is received and forwarding the request message to a next one of the switches forming said route.

19. The network of claim 11 further comprising

at said second one of the switches, responsive to receipt of the call request, forwarding a copy of the connection list contained in the received call request message to said first one of the switches.

20. The network of claim 12 further comprising

at said first one of the switches, responsive to receipt of the connection list, optimizing the path to said second one of the switches and redirecting the sending of cells to said one wireless terminal over said optimized path by appending a tail cell to a queue of cells addressed to said one wireless terminal and effectuating said redirection when said tail cell reaches the top of said queue such that newly received messages addressed to said one wireless terminal are thereafter forwarded over the optimized path.

21. The network of claim 12 further comprising

at said second one of the switches, responsive to receipt of the call set-up message, optimizing the path to said first one of the switches and redirecting the sending of cells originated by said one wireless terminal over said optimized path by appending a tail cell to a queue of such originated cells that are to be sent to said first one of the switches and effectuating said redirection when said tail cell reaches the top of said queue such that new cells originated by said one wireless terminal are thereafter forwarded over the optimized path.

23. The network of claim 11 wherein each user terminal served by said network is associated with a respective scope value S.

24. A network comprising a plurality of switches, said switches being formed into respective peer groups, said peer groups being formed into a hierarchical logical network of L levels, where L≧

1, each of said switches being associated with a plurality of base stations each operative for communicating with wireless terminals located in respective communications cells, individual ones of said switches serving as a home switch for respective ones of said wireless terminals, said network further comprising

at one of said switches, responsive to receiving from an associated base station a registration message originating from one of said wireless terminals, generating a message containing information relating to the current location of said one of said wireless terminals and sending the message to the other switches that are within S levels of said one of said switches, and

at each of said other switches, responsive to receipt of said message, updating an associated reachability database to indicate the current location of said one of said wireless terminals.

25. A network comprising a plurality of switches, said switches being formed into respective peer groups, said peer groups being formed into a hierarchical logical network of L levels, where L≧

1, each of said switches being associated with a plurality of base stations each operative for communicating with wireless terminals located in respective communications cells, individual ones of said switches serving as a home switch for respective ones of said wireless terminals, said network further comprising at one of said switches, responsive to receiving from an associated base station a registration message originating from one of said wireless terminals, generating a message containing information relating to the current location of said one of said wireless terminals and sending the message to the other switches that are within S levels of said one of one of said switches and to a switch previously serving said one of said wireless terminals,

at each said other switches, responsive to receipt of said message, updating an associated reachability database to indicate the current location of said one of said wireless terminals, and

at said switch previously serving said one of said wireless terminals, responsive to receipt of said message, setting a pointer pointing to the current location of said one of said wireless terminals and updating an associated reachability database to indicate that said one of said wireless terminals may be reached via the home switch associated with said one of said wireless terminals if said previous switch is outside of the scope S of said one of said switches.

26. A wireless network comprising

a plurality of switches formed into respective peer groups, each of said switches being associated with a plurality of base stations each operative for communicating with wireless terminals located in a respective communications zone, individual ones of said switches serving as a home switch for respective ones of said wireless terminals, and

a plurality of location registers formed into S levels of location registers such that each of the location registers forming a first level of location registers is associated with a respective one of said peer groups of switches and such that each location register in a succeeding level of location registers is associated hierarchically with a group of location registers in a preceding level of location registers, where S≧

1,

wherein each of said first level of location registers is operative for tracking the location of wireless terminals currently served by base stations connected to one of the switches forming the respective one of said peer groups and each succeeding level of location registers is operative for tracking the location of wireless terminals currently tracked by the location registers forming the preceding level of location registers.

27. The wireless network of claim 26 further comprising

at one of said switches, responsive to receipt of a registration message originated by one of said wireless terminals, sending a registration message identifying said one of said switches and identity of the base station serving the wireless terminal that originated the registration message to the associated one of the location registers in said first level of location registers, which then updates the information identifying the current location of the wireless terminal.

28. The wireless network of claim 27 wherein said associated level location register further operates to cause the identifying information to be sent to each higher level location register in the hierarchy which does not have that information.

29. The wireless network of claim 27 wherein if the associated next higher level location register is at the S level in said hierarchy, then that location register sends the registration message to the home switch if said one switch is not within the scope S of the last one of the switches to serve the wireless terminal.

30. The wireless network of claim 27 further comprising

at said one of said switches, responsive to receipt of the registration message, sending a registration cancellation message to another one of said switches which last served said wireless terminal, said other one of said switches being operative for sending the cancellation message to its associated location register.

31. The wireless network of claim 27 further comprising

at said one of said switches, responsive to receipt of the registration message, sending a registration cancellation message to another one of said switches which last served said wireless terminal, said other one of said switches being operative for sending the cancellation message to its associated location register only if said other one and said one of said switches are not in the same peer group.

32. The wireless network of claim 31 wherein said associated location register operates to update its information relating to said wireless terminal and to send the cancellation message to an associated location register at a next higher level in said hierarchy.

33. The wireless network of claim 26 further comprising

at another one of said switches, responsive to receipt of a call addressed to another one of the wireless terminals, forwarding said call to the other one of the wireless terminals if that wireless terminal is within a cell location served by a base station associated with said other one of said switches, if the other one of the wireless terminals is not in within any cell served by any base station associated with the other one of said switches, then said other one of said switches generates a location request message and sends that request message to its associated location register.

34. The wireless network of claim 33 wherein said location register associated with said other one of said switches, responsive to receipt of the location request message and responsive to not having information relating to the location of the said other wireless terminal, sends the location request message to a next higher level location register, and, responsive to having such information, sends information relating to the location of said other wireless terminal to said other one of said switches.

35. The wireless network of claim 33 wherein said location register associated with said other one of said switches, responsive to receipt of the location request message and responsive to not having information relating to the location of the said other wireless terminal, forwards the location request message to a higher level location register so that the request message may then propagate upwards through said hierarchy of location registers until it is received by a location register having information relating to the location of said other wireless terminal.

36. The wireless network of claim 35 wherein when said request message is received upwards by a location register positioned at the S level in the hierarchy of location registers and that location register does not have such information, then that location register forwards the location request to the home switch associated with the other wireless terminal, the home switch, responsive to receipt of the location request, forwards the location request to the location register that is positioned at the S level in the hierarchy and currently tracking the location of the other wireless terminal.

37. The wireless network of claim 35 wherein each of said location registers positioned above a first level in the hierarchy of location registers, responsive to receipt of the location request and responsive to having partial information relating to the location of the other wireless terminal, forwards the location request to an associated location register positioned at a next, lower level in said hierarchy and having the additional information relating to the location of the other wireless terminal, and wherein the location register positioned at the first level returns the information relating to the location of the other wireless terminal to said other one of said switches.

38. The wireless network of claim 36 wherein each of said location registers positioned above a first level in the hierarchy of location registers, responsive to receipt of the location request and responsive to having partial information relating to the location of the other wireless terminal, forwards the location request to an associated location register positioned at a next, lower level in said hierarchy and having the additional information relating to the location of the other wireless terminal, and wherein the location register positioned at the first level returns the information relating to the location of the other wireless terminal to said other one of said switches.

39. The wireless network of claim 26 wherein the value of S may be different for different wireless networks.