Active service redirection for a private femto cell

• US 20090061873A1
• Filed: 08/31/2007
• Published: 03/05/2009
• Est. Priority Date: 08/31/2007
• Status: Active Grant

• Current Assignee: Cellco Partnership, Inc. (Verizon Communications Inc.)
• Original Assignee: Cellco Partnership, Inc. (Verizon Communications Inc.)
• Inventors: Bao, Derek Hongwei, Chiang, David
• Granted Patent: US 8,219,100 B2
• Time in Patent Office: Days
• US Class Current: 455/436
• CPC Class Codes: H04W 16/32 Hierarchical cell structures
• CPC Class Codes: H04W 36/22 for handling the traffic
• CPC Class Codes: H04W 36/38 by fixed network equipment
• CPC Class Codes: H04W 84/045 using private Base Stations, e.g. femto Base Stations, home Node B

Abstract

A femto cell at a customer premises, such as an IP-based femto Base Transceiver System (IP-BTS), can be configured as a “private access” node intended to service a limited set of mobile stations. However, mobile stations not associated with the private femto cell may acquire and lock onto the femto BTS. To avoid service blockages in such cases, the private femto BTS will allow call access attempts by, and call deliveries to, a non-associated mobile station, despite the “private access” configuration. However, upon completion of call set-up, the non-associated mobile station is directed to initiate handoff, from the private femto cell coverage provided by the femto BTS into a cell coverage of a base station of the macro network, to conserve femto cell resources for use in servicing calls of the associated mobile station(s).

Claims

1. A method of processing a call for a mobile station operable through base stations of a macro wireless communication network, via a femto cell designated as private, comprising steps of:

receiving a request to set-up a call session for the mobile station through the private femto cell;

determining that the mobile station is not a station associated with the private femto cell permitted to obtain service through the private femto cell; and

upon determining that the mobile station is not associated with the private femto cell;

(1) initiating establishment of the requested call session for the non-associated mobile station through the private femto cell; and

(2) upon successful establishment of the requested call session for the non-associated mobile station through the private femto cell, automatically directing the non-associated mobile station to initiate a handoff of the call session from the private femto cell to a base station of the macro wireless communication network to force the call session out of private femto cell coverage into macro network coverage.

2. The method of claim 1, wherein the step of directing the mobile station to initiate handoff comprises transmitting a command via the private femto cell to the mobile station, instructing the mobile station to initiate a hard handoff of the call session from the private femto cell to the base station of the macro wireless communication network.

3. The method of claim 1, wherein the step of directing the mobile station to initiate handoff comprises transmitting a command via the private femto cell to the mobile station, instructing the mobile station to initiate a hard handoff of the call session to a designated frequency channel of the base station of the macro wireless communication network.

4. The method of claim 3, wherein:

the private femto cell is configured to operate on one or more of a plurality of predefined frequency channels; and

the frequency channel of the base station of the macro wireless communication network designated for the hard handoff is different from the predefined frequency channels.

5. The method of claim 1, wherein the step of initiating establishment of the requested call session for the non-associated mobile station through the private femto cell comprises:

determining whether or not sufficient resources are available through the private femto cell to handle set-up of the requested call session for the mobile station; and

initiating establishment of the requested call session for the mobile station through the private femto cell, upon determining that sufficient resources are available through the private femto cell to handle set-up of the requested call session.

6. The method of claim 1, further comprising:

determining whether or not the requested call session relates to an emergency call from the mobile station;

wherein the determining that the mobile station is not associated with the private femto cell is responsive to a determination that the requested call session does not relate to an emergency call from the mobile station.

7. The method of claim 1, wherein the requested call session relates to a call from the non-associated mobile station to a destination station.

8. The method of claim 1, wherein the requested call session relates to a call from an originating station intended for completion to the non-associated mobile station.

9. A system offering mobile communications services for mobile stations, the system comprising:

a macro network providing wireless public mobile communications services in a region, the macro network comprising base stations providing wireless communications with the mobile stations, a base station controller coupled to the base stations for controlling mobile station handoff operations through the base stations and a mobile switching center for routing calls for mobile stations via the base stations;

femto cell base transceiver systems installed in premises within the region, for wireless communications with mobile stations, wherein one of the femto cell base transceiver systems is configured as a private femto cell for servicing one or more of the mobile stations indicated as associated with the one femto cell base transceiver system of the private femto cell;

a switch coupled for communication with the femto cell base transceiver systems and coupled for communication with the mobile switching center of the macro wireless network, the switch being configured to control calls through the femto cell base transceiver systems including handoff of calls, the call control by the switch including functions of;

receiving a request to set-up a call session for an identified mobile station through the femto cell base transceiver system of the private femto cell;

determining that the identified mobile station is not associated with the private femto cell; and

upon determining that the identified mobile station is not associated the private femto cell;

(1) initiating establishment the requested call session for the identified mobile station through the femto cell base transceiver system of the private femto cell and through the switch; and

(2) upon successful establishment of the requested call session, automatically directing the identified mobile station to initiate a handoff of the call session from the femto cell base transceiver system of the private femto cell to one of the base stations of the macro communication network to force the call session out of private femto cell coverage into macro network coverage.

10. The system of claim 9, wherein:

each of the femto cell base transceiver systems comprises an Internet Protocol-Base Transceiver System (IP-BTS); and

the switch is configured to communicated with the IP-BTSs using Internet Protocol (IP) communications.

11. The system of claim 10, wherein the switch comprises a wireless soft switch coupled for communication with the femto cell base transceiver systems through a data.

12. The system of claim 10, wherein the wireless soft switch is configured to communicate with the IP-BTSs using the IP communications through the Internet.

13. The system of claim 9, wherein:

the base stations of the macro communication network comprise CDMA equipment configured for wireless communication with the mobile stations in accord with a code division multiple access wireless protocol; and

the femto cell base transceiver systems comprise CDMA equipment configured for wireless communication with the mobile stations in accord with said code division multiple access wireless protocol.

14. The system of claim 9, wherein:

the function of the switch to automatically direct the identified mobile station to initiate a handoff of the call session comprises transmitting a command from the femto cell base transceiver system of the private femto cell to the identified mobile station, instructing the identified mobile station to initiate a hard handoff of the call session from the private femto cell to the base station of the macro communication network; and

the switch also provides signaling to the macro network to facilitate the hard handoff of the call session to the base station of the macro communication network.

15. The system of claim 9, wherein:

the femto cell base transceiver systems are configured for operating on one or more channels selected from a plurality of predefined channels for femto cell communications; and

the function of the switch to automatically direct the identified mobile station to initiate a handoff of the call session comprises transmitting a command from the femto cell base transceiver system of the private femto cell to the identified mobile station, instructing the identified mobile station to initiate a handoff to a frequency channel of the base station of the macro communication network that is not one of the predefined channels for femto cell communications.