Reconnection of wireless calls to mobile units in border cells

• US 20050159161A1
• Filed: 01/20/2004
• Published: 07/21/2005
• Est. Priority Date: 01/20/2004
• Status: Active Grant

• Current Assignee: WSOU Investments, LLC (WSOU Holdings, LLC)
• Original Assignee: Lucent Technologies, Inc. (Nokia Corporation)
• Inventors: Hunter, Karla Rae, Lou, E-Ling, Halsell, Victoria Marie, Gayde, Ruth Schaefer, Florkey, Cynthia
• Granted Patent: US 7,107,054 B2
• Time in Patent Office: Days
• US Class Current: 455/450
• CPC Class Codes: H04W 36/12 Reselecting a serving backbone network switching or routing node

Abstract

Reconnection of a mobile unit to a call session controlled by a first MSC is supported responsive to a network-initiated or mobile-originated reconnect attempt even in instances where the mobile unit has roamed to a border cell controlled by a second MSC. In a network-initiated reconnect attempt, the first MSC sends a suspended call page request to a second MSC. The second MSC pages the mobile unit, sets up a bearer channel to the mobile unit, and sends to the first MSC a suspended call page response including indicia of the bearer channel set up by the second MSC. The first MSC establishes a bearer channel to the second MSC thereby reconnecting the mobile unit to the call session. In a mobile-originated reconnect attempt, the mobile unit sends a mobile-originated reconnect message to the second MSC. If the second MSC does not find session information associated with the call, it sends a suspended call handoff request to the first MSC causing the first MSC to query a database to find indicia of the call session, establish a bearer channel to the second MSC and send to the second MSC a suspended call handoff acknowledgement including information associated with the call session. The second MSC establishes a bearer channel to the mobile unit thereby reconnecting the mobile unit to the call session.

Claims

1. A method of performing a network-initiated reconnect of a mobile unit having experienced a service interruption during a call session controlled by a first mobile switching center (MSC) and not responding to a page attempt from the first MSC, the method comprising a second MSC:

receiving from the first MSC, a suspended call page request;

paging the mobile unit;

setting up a bearer channel to the mobile unit; and

sending to the first MSC a suspended call page response including indicia of the bearer channel set up by the second MSC to the mobile unit.

2. The method of claim 1, further comprising the first MSC:

receiving the suspended call page response; and

establishing a bearer channel to the second MSC thereby reconnecting the mobile unit to the call session.

3. A method of performing a mobile-originated reconnect of a mobile unit having experienced a service interruption during a call session controlled by a first mobile switching center (MSC), the method comprising the first MSC:

receiving, from a second MSC, a suspended call handoff request;

querying a database to find indicia of the call session;

sending to the second MSC a suspended call handoff acknowledgement including information associated with the call session; and

establishing a bearer channel to the second MSC.

4. The method of claim 3, further comprising the second MSC:

receiving the suspended call handoff acknowledgement; and

establishing a bearer channel to the mobile unit thereby reconnecting the mobile unit to the call session.

5. The method of claim 3, wherein the step of the first MSC receiving a suspended call handoff request is preceded by the second MSC:

receiving a mobile-originated reconnect (MORC) message issued by the mobile unit; and

querying a database for indicia of the call session; and

sending to the first MSC the suspended call handoff request responsive to not finding indicia of the call session.

6. In a wireless communication system wherein a call is established between a mobile unit and one or more participating units, the mobile unit being served by a first mobile switching center (MSC) when a service interruption is detected to the mobile unit, a method comprising:

maintaining bearer channels from the first MSC to the one or more participating units, at least temporarily, while awaiting possible reconnection of the mobile unit;

determining that the mobile unit has roamed to a location served by a second MSC;

establishing a bearer channel from the second MSC to the mobile unit; and

establishing a bearer channel between the first and second MSC, thereby completing a reconnect of the mobile unit to the call.

7. The method of claim 6, wherein the step of determining that the mobile unit has roamed to a location served by a second MSC comprises:

unsuccessfully attempting by the first MSC to page the mobile unit;

sending from the first MSC to the second MSC, a suspended call page request;

responsive to the suspended call page request, attempting by the second MSC to page the mobile unit; and

if the page is answered, sending from the second MSC to the first MSC a suspended call page response indicating presence of the mobile unit within the location served by the second MSC; and

receiving the suspended call page response by the first MSC.

8. The method of claim 7, wherein the suspended call page request includes a session identifier associated with the call, the suspended call page response including the session identifier and bearer channel information associated with the bearer channel established from the second MSC to the mobile unit.

9. The method of claim 7, wherein the suspended call page request includes a mobile unit identifier associated with the mobile unit, the suspended call page response including the mobile unit identifier and bearer channel information associated with the bearer channel established from the second MSC to the mobile unit.

10. The method of claim 7, further comprising:

starting a wait timer defining a waiting period to allow for reconnect of the mobile unit to the call; and

ending the call if the mobile unit is not reconnected to the call before expiration of the waiting period.

11. The method of claim 6, wherein the step of determining that the mobile unit has roamed to a location served by a second MSC comprises:

receiving at the second MSC a mobile-originated reconnect (MORC) message issued by the mobile unit, the MORC message indicating presence of the mobile unit within the location served by the second MSC;

sending from the second MSC to the first MSC, a suspended call handoff request indicating presence of the mobile unit within the location served by the second MSC; and

receiving at the first MSC, the suspended call handoff request.

12. The method of claim 11, further comprising the first MSC, responsive to receiving the suspended call handoff request from the second MSC:

retrieving session information associated with the interrupted call of the mobile unit; and

sending to the second MSC, a suspended call handoff acknowledgement including at least a portion of the session information.

13. The method of claim 12, further comprising:

starting a wait timer defining a waiting period to allow for reconnect of the mobile unit to the call; and

ending the call if the mobile unit is not reconnected to the call before expiration of the waiting period.