Method and system for distributed control in wireless cellular and personal communication systems

• US 6,081,715 A
• Filed: 03/18/1997
• Issued: 06/27/2000
• Est. Priority Date: 10/17/1994
• Status: Expired due to Term

• Current Assignee: Alcatel-Lucent USA, Inc. (Nokia Corporation)
• Original Assignee: Lucent Technologies, Inc. (Nokia Corporation)
• Inventors: La Porta, Thomas F., Ramjee, Ramachandran, Veeraraghavan, Malathi
• Primary Examiner(s): Chin, Wellington
• Assistant Examiner(s): Ferguson, Keith
• Application Number:
  US08/819,929
• Time in Patent Office: 1,197 Days
• Field of Search: 455/445, 455/432, 455/433, 455/434, 455/435, 455/436, 455/437, 455/438, 455/439, 455/440, 455/441, 455/442, 455/550, 455/561, 455/552, 455/422, 370/312, 370/331, 370/338, 370/390, 370/396, 370/522
• US Class Current: 455/445
• CPC Class Codes: H04L 2012/5629 Admission control
• CPC Class Codes: H04Q 11/0478 Provisions for broadband connections
• CPC Class Codes: H04W 36/12 Reselecting a serving backbone network switching or routing node
• CPC Class Codes: H04W 8/04 Registration at HLR or HSS [Home Subscriber Server]
• CPC Class Codes: H04W 8/08 Mobility data transfer

Abstract

A system for distributed control in wireless cellular and personal communication systems includes separate servers for performing call control and connection control functions, thereby obviating the need for a mobile switching or other switch to be anchored for the duration of a call. During a registration procedure, visiting location servers track only roaming mobiles, rather than tracking both roaming mobiles as well as mobiles located in their home network. Direct signalling links between servers and base stations, or other servers, located in different networks allow roaming mobiles to contact their home networks for service at all times, thereby obviating the need for passing signalling information for mobiles when they are not involved in a call. The use of multicast signalling with asynchronous transfer mode switches, permits specified channel control functions to take place concurrently in channel servers associated with base station and switches that form a segment of the route for a call. Similarly, specified call control functions are performed concurrently with mobile location functions, thereby decreasing the delays in setting up a call.

Claims

1. A method of tracking the location of a mobile having a home network, said method comprising the steps of:

generating a registration message;

performing the following steps if said mobile is located in its home network;

(a) forwarding registration information to a home location server for said mobile; and

(b) storing a mobile-to-cluster mapping for said mobile in said home location server; and

performing the following steps if said mobile is not located in its home network;

(a) forwarding said registration information to a visitor location server tracking said mobile;

(b) storing a mobile-to-cluster mapping for said mobile in said visitor location server if said registration message indicates a cluster change;

(c) forwarding said registration information to said home location server for said mobile if said registration message indicates that said mobile is powering up or powering down; and

(d) storing in said home location server network identifier and visitor location server identifier corresponding to the location of said calling mobile.

2. A method of releasing a call from a calling end system to a called end system to a called end system, where at least either said calling end system or said called end system is a mobile, said method comprising the steps of:

generating a release-order message;

sending a release-call message to call servers involved in said call;

sending a release-connection message to a connection server corresponding to the one of said call servers which has a record of connections involved in said call; and

performing a release-connection routine wherein resources, which are used in a plurality of channel servers for releasing connections and managing switch resources, said channel servers associated with base stations and switches which form a segment of a route for said call, are released concurrently, wherein said release-call routine further comprises the step of sending a multicast drop channel message to said plurality of channel servers.

3. A method of handing off a call comprising the steps of:

generating a handoff-order message identifying a previous base station which comprises a first end of an old route for said call;

forwarding said handoff-order message to said previous base station;

sending a handoff segment message from a channel server associated with said previous base station to a new base station;

establishing in response to the handoff segment message a new segment of a route for said call from said new base station to a switch identified as a second end of said old segment by setting up a translation table of switch resources for the new segment;

setting up a new translation from a channel in said old route to a channel associated with said new segment;

identifying to said switch each channel server involved in said new segment; and

communicating to a connection server responsible for said old segment the change from said old segment to said new segment.

4. A roamer call server for use in a first home network in conjunction with a distributed control multi-network telecommunication system, said roamer call server comprising:

a processor for handling call control functions for users of the first home network who are roaming or visiting another network;

memory for storing user profile information for said users;

an input for receiving a request to provide call control functions for a roaming user visiting another network; and

an output for providing call control functions including a basic call state model for a call and for triggering implicit services subscribed to by said roaming user consistent with the stored user profile information, whereby mobiles of roaming users are permitted to contact the first home network for services at all times, thereby obviating the need for different networks to share competitive information.

5. A method of setting up a call from a calling end system to a called end system, where at least either said calling end system or said called end system is a mobile, said method comprising the steps of:

generating a call origination message;

performing a call control routine for said call; and

performing a connection establishment routine comprises the steps of;

(a) receiving a setup connections message;

(b) finding a route from said calling end system to said called end system for said call;

(c) performing a connection admission routine with respect to each segment of said route; and

(d) performing a connection setup routine with respect to each segment of said route;

wherein said connection admission routine comprises the step of performing channel reservation functions concurrently in a plurality of channel servers associated with base stations and switches which form a segment of said route and wherein said connection setup routine comprises the step of performing setup translation functions concurrently in said plurality of channel servers.

6. The method of claim 5, wherein said connection admission routine comprises the step of sending a multicast reserve channel message to said plurality of channel servers.

7. The method of claim 5, wherein said connection setup routine further comprises the step of sending a multicast setup translation message to said plurality of channel servers.

8. A method of setting up a call from a calling end system to a called end system, where at least either said calling end system or said called end system is a mobile, said method comprising the steps of:

generating a call origination message;

performing a call control routine for said call; and

performing a connection establishment routine for said call;

wherein said call control routine comprises the steps of;

(a) sending a setup call message to a call server serving said calling end system;

(b) creating a state machine for said call;

(c) invoking implicit services for said calling end system;

(d) creating a record for mapping connections for said call;

(e) identifying a call server serving said called end system, a connection server for said called end system and a gateway switch for said called end system;

(f) communicating with said call server for said called end system to invoke implicit services for said called end system; and

(g) sending a setup connections message to a connection server for said calling end system;

and wherein the steps (b), (c) and (d) of said call control routine are performed concurrently with the steps (e) and (f) of said call control routine.

9. The method of claim 8 wherein the step of sending a setup call message to a call server serving said calling end system comprises the steps of:

sending a setup call message to a call server located in the same cluster as said calling end system if said calling end system is a mobile located in its home network; and

sending a setup call message to a roamer call server located in the home network of said calling end system if said calling end system is a mobile which is not located in its home network.

10. The method of claim 8 wherein the step of identifying comprises the following steps if said called end system is a mobile located in its home network;

sending a find request to a home location server for said called end system; and

sending a find response to the call server serving said calling end system, wherein said find response specifies the call server serving said called end system, the connection server for said called end system and the gateway switch for said called end system.

11. The method of claim 8 wherein the step of identifying comprises the following steps if said called end system is a mobile located in its home network;

sending a find request to a home location server for said called end system;

sending a find request from said home location server to a visitor location server tracking said called end system;

sending a find response from said visitor location server to said home location server; and

sending at least one find response from said home location server to the call server to the call server serving said calling end system.

12. The method of claim 8 wherein the step of sending at least one find response to said call server serving said calling end system comprises the steps of:

sending a first find response specifying the call server serving said called end system; and

sending a second find response specifying the connection server for said called end system and the gateway switch for said called end system.

13. The method of claim 8 further including the step of performing a base station location routine if said called end system is a mobile, where said base station location routine is performed in parallel with step (f) of claim 12.

14. The method of claim 13 wherein said base station location routine comprises the following steps if said called end system is located in its home network:

sending a page request from a home location server for said called end system to all base stations located in the same cluster as said called end system;

generating a page order from each of said base stations; and

sending a page response to said home location server.

15. The method of claim 14 wherein said step of sending a page request comprises sending a multicast page request.

16. The method of claim 13 wherein the base station location routine comprises the following steps if said called end system is not located in its home network;

sending a page request from a visitor location server for said called end system to all base stations located in the same cluster as said called end system;

generating a page order from each of said base stations; and

sending a page response to said visitor location server.

17. The method of claim 16 wherein said step of sending a page request comprises sending a multicast page request.