Method and apparatus for completing a handover between wireless communication systems

• US 6,373,828 B1
• Filed: 06/26/1998
• Issued: 04/16/2002
• Est. Priority Date: 06/26/1998
• Status: Expired due to Term

• Current Assignee: Google Technology Holdings LLC (Alphabet Inc.)
• Original Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Inventors: Stewart, Randall R., Joyner, Tom, Noradt, Rich, Martinez, Edgar
• Primary Examiner(s): Nguyen, Chau
• Assistant Examiner(s): ABELSON, RONALD B
• Application Number:
  US09/105,340
• Time in Patent Office: 1,390 Days
• Field of Search: 455/73-91, 455/436-441, 455/550-575, 370/467, 370/351, 370/400, 370/238, 370/254, 370/331, 370/465, 370/432, 370/455, 370/433
• US Class Current: 370/331
• CPC Class Codes: H04W 36/14 Reselecting a network or an air interface

Abstract

A method and apparatus for a handover of a communication signal (370) associated with a mobile communication unit (116) between a Generic C-based wireless communication system (302) and a MSC-based wireless communication system (304), is disclosed. The handover method includes establishing a plurality of trunks (401) between a landline switch (316) and a MSC (317). The method also includes configuring a landline number routing table (403) and a landline trunk group table (404) in the landline switch (316), a mobile trunk group table (406) in the MSC (317), and establishing a message translation table (405) in the computing platform (312), such that one of the plurality of trunks and an associated signaling path to the computing platform (312) are always selected when the handover is required.

Claims

1. A method for completing a handover of a communication signal associated with a mobile communication unit from a first wireless communication system to a second wireless communication system, the first wireless communication system comprising a landline switching element, a computing platform and a first base station element, and the second wireless communication system comprising a mobile switching element and a second base station element, the method comprising:

establishing a plurality of trunks between the landline switching element and the mobile switching element, the plurality of trunks, when selected, capable of carrying user data traffic;

configuring a landline number routing table in the landline switching element, the landline number routing table automatically selecting the plurality of trunks upon receipt of a guide directory number (GDN);

configuring a landline trunk group table in the landline switching element, the landline trunk group table having as input an identity of the plurality of trunks and providing as output an identity of one of the plurality of trunks and an associated signaling path to the computing platform; and

establishing a message translation table in the computing platform, the message translation table capable of translating a ISUP signaling message from the landline switching element into an IS-41 signaling message suitable for receipt by the mobile switching element.

2. The method according to claim 1, wherein the step of establishing the plurality of trunks between the landline switching element and the mobile switching element further comprises the steps of:

configuring the plurality of trunks as ISUP trunk groups represented by a corresponding plurality of CIC numbers in the landline switching element; and

configuring the plurality of trunks as IS-41 trunk groups represented by a corresponding plurality of trunk group and member numbers in the mobile switching element, the corresponding plurality of trunk group and member numbers corresponding to the corresponding plurality of CIC numbers in the landline switching element.

3. The method according to claim 1, further comprising the step the steps of:

assigning a first signaling address to the computing platform;

assigning a second signaling address to the landline switching element; and

assigning a third signaling address to the mobile switching element.

4. The method according to claim 3, wherein a signaling address comprises a destination point code.

5. The method according to claim 3, wherein the step of configuring a landline trunk group table further comprises the step of:

providing a trunk group type for the plurality of trunks, a number of trunks in the plurality of trunks, a corresponding CIC number for each trunk in the plurality of trunks, a trunk group termination point for the plurality of trunks, and the first signaling address representing the computing platform for the associated signaling path.

6. The method according to claim 1, further comprising the steps of:

detecting, by the first base station element, that a handover of the communication signal is desired;

notifying the computing platform via an outbound handover request message that a handover of the communication signal to the second wireless communication system is desired, the outbound handover request message including an identity of the second base station system;

calling the GDN by the computing platform in response to receipt of the handover request message; and

selecting an idle user data path between the first base station element and the landline switching element, the idle user data path between the first base station element and the landline switching element identified by a terminal directory number (TDN).

7. The method according to claim 6, further comprising the steps of:

selecting, via the landline routing table, the plurality of trunks between the landline switch and the MSC upon receipt of the directory number by the landline switching element;

selecting one of the plurality of trunks for carrying user data traffic, the one of the plurality of trunks, the one of the plurality of trunks identified by a CIC number; and

selecting a signaling path between the landline switching element and the computing platform for carrying signaling messages based on the landline trunk group table, the selection of the signaling path based upon the first address as a table entry in the landline trunk group table associated with the one of the plurality of trunks.

8. The method according to claim 7, further comprising the steps of:

generating an integrated services digital network—

user part (ISUP) initial address message (IAM), the ISUP IAM comprising the TDN, the GDN, and the CIC number;

forwarding the ISUP IAM from the landline switching element to the computing platform as a result of the selection of the signaling path;

acknowledging receipt of the ISUP IAM by the computing platform with an ISUP address complete message (ACM) sent from the computing platform to the landline switching element; and

generating an ISUP answer message by the computing platform sent from the computing platform to the landline switch, the ISUP answer message indicating an establishment of a new voice path between the first base station element and the mobile switching element.

9. The method according to claim 7, further comprising the steps of:

generating an IS-41 facilities request message by the AM/VLR, the IS-41 facilities request message based on information previously received in the handover request message and the ISUP IAM, the IS-41 facilities request message including the mobile station identity, an identity of the first base station element, an identity of the second base station element, and an identity of the trunk group and member number of the one of the number of trunks selected from the trunk group, the trunk group and member number translated by the message translation table using the corresponding CIC number;

forwarding the IS-41 facilities request message to the mobile switching element; and

forwarding an IS-41 circuit voice channel connected message from the mobile switching element to the computing platform in response to receipt of the IS-41 facilities request message by the mobile switching element, IS-41 circuit voice channel connected message indicating an extension of the new voice path between the first base station element and the mobile switching element, to the second base station element.

10. The method according to claim 9, further comprising the step of performing a handover of the communication signal from a first base station element to a second base station element.

11. The method according to claim 10, further comprising the steps of:

forwarding an IS-41 mobile on channel message from the mobile switching platform to the computing platform, the IS-41 mobile on channel message indicating an extension of the new voice path between the first base station element and the mobile switching element and the second base station element, to the mobile communication unit; and

forwarding an IS-634 handover complete message from the computing platform to the first base station element, the IS-634 handover complete message directing a cross-connection in the first base station system of the new voice path, and resulting in a dropping of the communication signal between the first base station element and the mobile station.

12. The method according to claim 1, wherein the first wireless communication system comprises a Generic C architecture based wireless communication system.

13. The method according to claim 1, wherein the landline switching element comprises a class 5 switch.

14. The method according to claim 1, wherein the second wireless communication system comprises one of a code division multiple access (CDMA) system, a time division multiple access (TDMA) system and an analog communication system.

15. A method for completing a handover of a communication signal associated with a mobile communication unit from a second wireless communication system to a first wireless communication system, the first wireless communication system comprising a landline switching element, a computing platform and a first base station element, and the second wireless communication system comprising a mobile switching element and a second base station element, the method comprising:

establishing a plurality of trunks between the landline switching element and the mobile switching element, the plurality of trunks, when selected, capable of carrying user data traffic;

configuring a mobile trunk group table in the mobile switching element, the mobile trunk group table having as input an identity of the plurality of trunks and providing as output an identity of one of the plurality of trunks and an associated signaling path to the computing platform; and

establishing a message translation table in the computing platform, the message translation table capable of translating an IS-41 signaling message from the mobile switching element into an integrated services digital network—

user part (ISUP) signaling message suitable for receipt by the landline switching element.

16. The method according to claim 15, wherein the step of establishing the plurality of trunks between the landline switching element and the mobile switching element further comprises the steps of:

configuring the plurality of trunks as IS-41 trunk groups represented by a corresponding plurality of trunk group and member numbers in the mobile switching element; and

configuring the plurality of trunks as ISUP trunk groups represented by a corresponding plurality of CIC numbers in the landline switching element, the corresponding plurality of CIC numbers corresponding to the corresponding plurality of trunk group and member numbers in the mobile switching element.

17. The method according to claim 15, further comprising the step the steps of:

assigning a first signaling address to the computing platform;

assigning a second signaling address to the landline switching element; and

assigning a third signaling address to the mobile switching element.

18. The method according to claim 17, wherein a signaling address comprises a destination point code.

19. The method according to claim 17, wherein the step of configuring a mobile trunk group table further comprises the step of:

providing a trunk group type for the plurality of trunks, a number of trunks in the plurality of trunks, a corresponding trunk group and member number for each trunk in the plurality of trunks, a trunk group termination point for the plurality of trunks, and the first signaling address representing the computing platform for the associated signaling path.

20. The method according to claim 15, further comprising the steps of:

detecting, by the second base station element, that a handover of the communication signal is desired;

notifying the mobile switching element a handover of the communication signal to the first wireless communication system is desired via an outbound handover request message, the outbound handover request message comprising an identity of the second base station element and an identity of the landline switching element;

translating the identity of the landline switching element by the mobile switching element;

selecting the plurality of trunks between the landline switching element and the mobile switching element as a result of translating the identity of the landline switching element;

selecting one of the plurality of trunks for carrying user data traffic, the one of the plurality of trunks identified by a trunk group and member number; and

selecting a signaling path between the mobile switching element and the computing platform for carrying signaling messages based on the mobile trunk group table, the selection of the signaling path based upon the first address as a table entry in the mobile trunk group table associated with the one of the plurality of trunks.

21. The method according to claim 20, wherein selecting the second signaling path comprises the steps of:

generating an IS-41 message, the IS-41 message comprising an identity of the first base station element, an identity of the landline switching element, and the identity of the one of the plurality of trunks; and

forwarding the IS-41 message from the mobile switching element to the computing platform.

22. The method according to claim 21, wherein the IS-41 message comprises a IS-41 facilities request message.

23. The method according to claim 21, further comprising the steps of:

selecting a GDN by the computing platform, the selection of the GDN based on a translation of the IS-41 message by the message translation table;

selecting a CIC number by the computing platform, the selection of the CIC number based on a translation of the IS-41 message by the message translation table;

selecting an idle user data path between the first base station element and the landline switching element, the idle user data path between the first base station element and the landline switching element identified by a terminal directory number (TDN);

formulating an ISUP initial address message (IAM) by the computing platform, the ISUP IAM comprising the TDN, the GDN, and the CIC number; and

forwarding the ISUP IAM message to the landline switching element.

24. The method according to claim 23, further comprising the steps of:

acknowledging receipt of the ISUP IAM message by the landline switching element to the computing platform;

forwarding a call setup message from the landline switching element to the computing platform;

forwarding an answer message from the computing platform to the landline switching element upon receipt of the call setup message by the computing platform; and

forwarding an ISUP answer message from the landline switching element to the computing platform upon receipt of the answer message by the landline switching element, the ISUP answer message indicating an establishment of a new voice path between the mobile station and the first base station system via the second base station element, the mobile switching element and landline switching element.

25. The method according to claim 24, further comprising the steps of:

forwarding an inbound handover request message from the computing platform to the first base station element, the inbound handover request message comprising the identity of the first base station element, an identity of the second base station element, an identity of the mobile station, and the TDN; and

forwarding an IS-41 circuit and voice channel connect message from the computing platform to the mobile switching element.

26. The method according to claim 25, further comprising the steps of:

forwarding a handover complete message from the first base station element to the computing platform upon acquisition on the communication signal by the first base station element;

forwarding an IS-41 mobile on channel message from the computing platform to the mobile switching platform; and

directing a cross-connection by the mobile switching element in the second base station element, the cross-connection connecting the new voice path and resulting in a dropping of the communication signal between the second base station element and the mobile station.

27. The method according to claim 15, wherein the first wireless communication system comprises a Generic C architecture based wireless communication system.

28. The method according to claim 15, wherein the landline switching element comprises a class 5 switch.

29. The method according to claim 15, wherein the second wireless communication system comprises one of a code division multiple access (CDMA) system, a time division multiple access (TDMA) system and an analog communication system.

30. An apparatus for completing a handover of a communication signal associated with a mobile communication unit between a first wireless communication system and a second wireless communication system, the first wireless communication system comprising a landline switching element, a computing platform and a first base station element, and the second wireless communication system comprising a mobile switching element and a second base station element, the apparatus comprising:

a plurality of trunks between the landline switching element and the mobile switching element, the plurality of trunks, when selected, capable of carrying user data traffic;

a landline number routing table in the landline switching element, the landline number routing table automatically selecting the plurality of trunks upon receipt of a guide directory number (GDN);

a landline trunk group table in the landline switching element, the landline trunk group table having as input an identity of the plurality of trunks and providing as output an identity of one of the plurality of trunks and an associated signaling path to the computing platform;

a mobile trunk group table in the mobile switching element, the mobile trunk group table having as input an identity of the plurality of trunks and providing as output an identity of one of the plurality of trunks and an associated signaling path to the computing platform; and

a message translation table in the computing platform, the message translation table capable of translating an ISUP signaling message into an IS-41 signaling message and capable of translating an IS-41 message into an ISUP signaling message.