Method, apparatus, and system for voice call fallback to circuit switched domain

• US 10,397,835 B2
• Filed: 05/03/2017
• Issued: 08/27/2019
• Est. Priority Date: 07/23/2009
• Status: Active Grant

• Current Assignee: Huawei Technologies Co., Ltd. (Huawei Investment & Holding Co., Ltd.)
• Original Assignee: Huawei Technologies Co., Ltd. (Huawei Investment & Holding Co., Ltd.)
• Inventors: Wu, Xiaobo, Liu, Hai, Xiao, Wei
• Primary Examiner(s): Elpenord, Candal
• Application Number:
  US15/585,390
• Publication Number:
  US 20170353894A1
• Time in Patent Office: 846 Days
• Field of Search: None
• CPC Class Codes: H04W 36/00224 between packet switched [PS] and circuit switched [CS] network technologies, e.g. circuit switched fallback [CSFB]
• CPC Class Codes: H04W 36/142 over the same radio air interface technology
• CPC Class Codes: H04W 68/00 User notification, e.g. alerting and paging, for incoming communication, change of service or the like
• CPC Class Codes: H04W 72/23 in the downlink direction of a wireless link, i.e. towards a terminal
• CPC Class Codes: H04W 76/10 Connection setup
• CPC Class Codes: H04W 8/26 Network addressing or numbering for mobility support

Abstract

A method for voice call fallback to a circuit switched (CS) domain disclosed in the present invention includes: receiving a Service Request message from a calling user equipment (UE), where the Service Request message includes called number information of a voice call in a CS domain, instructing an evolved NodeB (eNB) to initiate circuit switched fallback (CSFB) handover; receiving a Handover Request message from the eNB, where the Handover Request message includes information required for CS handover, selecting a mobile switching center (MSC) and sending a packet switched (PS) to CS Handover Request message to the MSC, where the PS to CS Handover Request message carries information required for the CS handover and a called number so that the MSC calls a called UE. The corresponding apparatuses and systems are also disclosed. The technical solution of the present invention can reduce the connection delay.

Claims

1. A method for voice call fallback to a circuit switched (CS) domain, comprising:

receiving, by a user equipment (UE), a circuit switched (CS) paging request message from a mobility management entity (MME);

sending, by the UE, a service request message to the MME;

receiving, by a base station, a circuit switched fallback (CSFB) indication from the MME, wherein the CSFB indication provides instructions for the base station to perform a handover for the UE to a CS domain of a 2nd generation/3rd generation (2G/3G) network;

transmitting, by the base station, a handover request message to the MME in response to the CSFB indication, wherein the handover request message provides instructions for the MME to transmit a packet switched (PS) to CS handover request message to a mobile switching center (MSC), the PS to CS handover request message provides instructions for the MSC to return a PS to CS handover response message to the MME, wherein the PS to CS handover response message comprises CS resource information prepared by a target base station subsystem/radio network subsystem (BSS/RNS);

receiving, by the base station, a handover command message from the MME;

transmitting, by the base station, the handover command message to the UE;

receiving, by the UE, the handover command message from the base station; and

accessing, by the UE, the 2G/3G network in accordance with the handover command messages.

2. The method according to claim 1, further comprising:

sending, by the UE, information indicating whether the UE supports enhanced circuit switched fallback (CSFB) to the MME.

3. The method according to claim 2, wherein the information indicating whether the UE supports enhanced CSFB is carried in an attach request message or a location update message.

4. The method according to claim 1, wherein the handover command message includes CS resource information prepared by a target base station subsystem or radio network subsystem (BSS/RNS).

5. The method according to claim 1, wherein the handover request message comprises information required for the handover to the CS domain.

6. The method according to claim 1, wherein after the base station receives the CSFB indication from the MME and before the base station transmits the handover request message to the MME, the method further comprises:

soliciting, by the base station, a measurement report for signal quality in the 2G/3G network from the called UE;

receiving, by the base station, the measurement report; and

deciding, by the base station, to instruct the MME to initiate the PS to CS handover procedure based on the measurement report and the CSFB indication.

7. A communication system, comprising:

a base station and a user equipment (UE);

the UE, configured to receive a circuit switched (CS) paging request message from a mobility management entity (MME); and

send a service request message to the MME;

the base station, configured to receive a circuit switched fallback (CSFB) indication from the MME, wherein the CSFB indication provides instructions for the base station to perform a handover for the UE to a CS domain of a 2nd generation/3rd generation (2G/3G) network, the base station is further configured to transmit a handover request message to the MME in response to the CSFB indication, wherein the handover request message provides instructions for the MME to transmit a packet switched (PS) to CS handover request message to a mobile switching center (MSC), wherein the PS to CS handover request message provides instructions for the MSC to return a PS to CS handover response message to the MME, the PS to CS handover response message comprises CS resource information prepared by a target base station subsystem/radio network subsystem (BSS/RNS), and the base station is further configured to receive a handover command message from the MME, to transmit the handover command message to the UE; and

the UE, further configured to receive the a handover command message from the base station; and

to access the 2G/3G network in accordance with the handover command messages.

8. The system non transitory computer readable medium according to claim 7:

wherein the UE is further configured to send information indicating whether the UE supports enhanced circuit switched fallback (CSFB) to the MME.

9. The system according to claim 8, wherein the information indicating whether the UE supports enhanced CSFB is carried in an attach request message or a location update message.

10. The system according to claim 7, wherein the handover command message includes CS resource information prepared by a target base station subsystem or radio network subsystem (BSS/RNS).

11. The system according to claim 7, wherein the handover request message comprises information required for the handover to the CS domain.

12. The system according to claim 7, wherein the base station is further configured to after the base station receives the CSFB indication from the MME and before the base station transmits the handover request message to the MME,

solicit a measurement report for signal quality in the 2G/3G network from the called UE;

receive the measurement report; and

decide to instruct the MME to initiate the PS to CS handover procedure based on the measurement report and the CSFB indication.

13. The system according to claim 7, wherein the system further comprises the MME.

14. The system according to claim 13, wherein the MME is configured to receive the handover request message from the base station, to transmit the PS to CS handover request message to the MSC, to receive, from the MSC, a response to the PS to CS handover request and to transmit the handover command message to the base station.

15. The system according to claim 7, wherein the system further comprises the MSC.