Handling an unreleased dedicated bearer of an internet protocol multimedia subsystem (IMS) call over long term evolution (LTE)

Abstract

This disclosure provides methods, apparatuses, and non-transitory computer-readable medium of handling an unreleased dedicated bearer. A method includes detecting an active dedicated evolved packet system (EPS) bearer between a user equipment (UE) and a packet data network (PDN), determining whether the active dedicated EPS bearer is being used by an internet protocol (IP) multimedia subsystem (IMS) application of the UE, and in response to determining that the active dedicated EPS bearer is not being used by the IMS application, performing a deactivation or modification operation on the active dedicated EPS bearer.

Description

HANDLING AN UNRELEASED DEDICATED BEARER OF AN INTERNET PROTOCOL MULTIMEDIA SUBSYSTEM (IMS) CALL OVERLONG TERM EVOLUTION (LTE)TECHNICAL FIELD

[0001] The present disclosure relates to wireless communications, and specifically to handling an unreleased dedicated bearer of an internet protocol multimedia subsystem (IMS) call over long term evolution (LTE).BACKGROUND

[0002] An internet protocol multimedia subsystem (IMS) voice service or video service call over long term evolution (LTE) can be referred to as a voice over LTE (VoLTE) or video over LTE (ViLTE) call. The VoLTE (or ViLTE) call is based on the IMS architecture and the session initiation protocol (SIP) signaling, and can be delivered as data flows within a dedicated evolved packet system (EPS) bearer. After the VoLTE (or ViLTE) call is ended, the dedicated EPS bearer should be deactivated, otherwise a next VoLTE (or ViLTE) call may not be successfully placed. However, the deactivation of the dedicated EPS bearer may not always be performed, causing a failure of the next VoLTE (or ViLTE) call.SUMMARY

[0003] Aspects of the disclosure provide a method of wireless communication at a user equipment (UE). The method includes detecting an active dedicated evolved packet system (EPS) bearer between the UE and a packet data network (PDN), determining whether the active dedicated EPS bearer is being used by an internet protocol (IP) multimedia subsystem (IMS) application of the UE, and in response to determining that the active dedicated EPS bearer is not being used by the IMS application, performing a deactivation or modification operation on the active dedicated EPS bearer.

[0004] Aspects of the disclosure provide an apparatus. The apparatus includes processing circuitry that detects an active EPS bearer between the apparatus and a PDN, determine whether the active dedicated EPS bearer is being used by an IMS application of the apparatus, and in response to determining that the active dedicated EPS bearer is not being used by the IMS application, perform a deactivation or modification operation on the active dedicated EPS bearer.

[0005] Aspects of the disclosure provide a non-transitory computer-readable medium storing instructions, which when executed by a processor, cause the processor to perform a method. The method includes detecting an active dedicated EPS bearer between a UE and a PDN, determining whether the active dedicated EPS bearer is being used by an IMS application of the UE, and in response to determining that the active dedicated EPS bearer is not being used by the IMS application, performing a deactivation or modification operation on the active dedicated EPS bearer.BRIEF DESCRIPTION OF THE DRAWINGS

[0006] Various embodiments of this disclosure that are proposed as examples will be described in detail with reference to the following figures, wherein like numerals reference like elements, and wherein:

[0007] FIG. 1 shows a voice over long term evolution (VoLTE) call flow according to an embodiment of the disclosure;

[0008] FIG. 2 shows a procedure of establishing a VoLTE call between a VoLTE mobile originating (MO) user equipment (UE) and a VoLTE mobile terminating (MT) UE according to an embodiment of the disclosure;

[0009] FIG. 3 A shows a normal case of a VoLTE call according to an embodiment of the disclosure;

[0010] FIG. 3B shows an abnormal case of a VoLTE call according to an embodiment of the disclosure;

[0011] FIG. 4A shows an example of a traffic flow template (TFT) information element (IE) according to an embodiment of the disclosure;

[0012] FIG. 4B shows an example of a TFT operation code according to an embodiment of the disclosure;

[0013] FIG. 4C shows an example of a packet filter list according to an embodiment of the disclosure;

[0014] FIGS. 5A-5C show three examples of handling an unreleased dedicated evolved packet system (EPS) bearer by triggering a bearer resource modification procedure according to embodiments of the disclosure;

[0015] FIG. 6 shows an example of locally releasing an unreleased dedicated EPS bearer according to an embodiment of the disclosure;

[0016] FIG. 7 shows an example of locally releasing a connection to an internet protocol multimedia subsystem (IMS) packet data network (PDN) according to an embodiment of the disclosure;

[0017] FIG. 8 shows an example of deactivating an unreleased dedicated EPS bearer by triggering a PDN disconnection procedure according to an embodiment of the disclosure;

[0018] FIG. 9 shows a flowchart outlining a process according to embodiments of the disclosure; and

[0019] FIG. 10 shows an exemplary computer system according to embodiments of the disclosure.DETAILED DESCRIPTION OF EMBODIMENTS

[0020] The detailed description set forth below in connection with the appended drawings is intended as a description of various configurations and is not intended to represent the only configurations in which the concepts described herein may be practiced. The detailed description includes specific details for the purpose of providing an understanding of various concepts. However, these concepts may be practiced without these specific details.

[0021] Several aspects of handling an unreleased dedicated bearer of an internet protocol (IP) multimedia subsystem (IMS) call over long term evolution (LTE) will now be presented with reference to various apparatuses and methods. These apparatuses and methods will be described in the following detailed description and illustrated in the accompanying drawings by various blocks, components, processes, algorithms, etc. (collectively referred to as “elements”). These elements may be implemented using electronic hardware, computer software, or any combination thereof. Whether such elements are implemented as hardware or software depends upon the particular application and design constraints imposed on the overall system.

[0022] An IMS voice service or video service call can be placed over LTE, and such a call can be referred to as a voice over LTE (VoLTE) call or a video over LTE (ViLTE) call. In this disclosure, VoLTE will be used in the following description for simplicity. However, it is noted that all the embodiments of this disclosure can also be applicable to ViLTE.

[0023] VoLTE uses IMS as a core network and session initiation protocol (SIP) as a signaling protocol. To place a VoLTE call, a network (NW) can negotiate with a user equipment (UE) through SIP signaling messages. If the negotiation is successful, a dedicated evolvedpacket system (EPS) bearer can be set up between the NW and the UE to deliver data packets of the VoLTE call.

[0024] FIG. 1 shows a VoLTE call flow 100 according to an embodiment of the disclosure. The VoLTE call flow 100 can include a default EPS bearer activation procedure, an IMS registration procedure 120, a VoLTE call establishment procedure 130, and a dedicated EPS deactivation procedure 140.

[0025] The VoLTE call flow 100 can start from the default EPS bearer activation procedure 110, in which a default EPS bearer can be established between a UE and a packet data network (PDN). The default EPS bearer can be used for SIP signaling of a VoLTE call. To establish the default EPS bearer, the UE can first request connectivity to the PDN by sending a "PDN CONNECTIVITY REQUEST" message to the PDN. In response to the "PDN CONNECTIVITY REQUEST" message, the PDN can send an "ACTIVATE DEFAULT EPS BEARER CONTEXT REQUEST" message to the UE. Upon receipt of the "ACTIVATE DEFAULT EPS BEARER CONTEXT REQUEST" message, the UE can respond to the PDN by sending an "ACTIVATE DEFAULT EPS BEARER CONTEXT ACCEPT" message.

[0026] After the default EPS bearer is successfully established, the VoLTE call flow 100 can perform the IMS registration procedure 120, in which the IMS authorization and the security negotiation can be performed between the UE and the PDN. If the IMS registration is successful, the PDN can become aware of UE context such as subscription profile, registration status, and the like.

[0027] After the IMS registration is successful, the VoLTE call flow 100 can perform the VoLTE call establishment procedure 130, in which a VoLTE call can be established using a dedicated EPS bearer. To establish a VoLTE call, the PDN can negotiate IP and port information with the UE through SIP signaling messages such as "INVITE" message and " 183 Session Progress" message. The PDN can collect the negotiation results (e.g., local and remote IP addresses, and local and remote port numbers) and include the negotiation results in an "ACTIVATED DEDICATED EPS BEARER CONTEXT REQUEST" message, which is sent from the PDN to the UE to establish the dedicated EPS bearer. Upon receipt of the "ACTIVATE DEDICATED EPS BEARER CONTEXT REQUEST" message, the UE can respond to the PDN by sending an "ACTIVATE DEDICATED EPS BEARER CONTEXT ACCEPT" message to the PDN. From the negotiation results included in the "ACTIVATED DEDICATED EPS BEARERCONTEXT REQUEST" message, the UE can set up a correct traffic flow template (TFT). Based on the TFT, the UE can forward IMS voice and / or video data packets to the negotiated IP address and port number through the dedicated EPS bearer, indicating that the VoLTE call has been successfully established.

[0028] After the VoLTE call is ended, the VoLTE call flow 100 can perform the dedicated EPS deactivation procedure 140 to deactivate the dedicated EPS bearer. To deactivate the dedicated EPS bearer, the PDN can send a "DEACTIVATE EPS BEARER CONTEXT REQUEST" message to the UE. The "DEACTIVATE EPS BEARER CONTEXT REQUEST" message can include an EPS bearer identity (EBI) of the dedicated EPS bearer. Upon receipt of the "DEACTIVATE EPS BEARER CONTEXT REQUEST" message, the UE can delete the dedicated EPS bearer identified by the EBI and respond to the PDN by sending a "DEACTIVATE EPS BEARER CONTEXT ACCEPT" message. The deactivation of the dedicated EPS bearer is desired for a successful placement of a next VoLTE call. It is noted that the default EPS bearer can still exist after the VoLTE call is ended.

[0029] FIG. 2 shows a procedure 200 of establishing a VoLTE call between a VoLTE mobile originating (MO) UE 201 and a VoLTE mobile terminating (MT) UE 202 according to an embodiment of the disclosure. The VoLTE call establishment procedure 200 can include a call setup phase 210 and a call active phase 220. To setup a VoLTE call, the MO UE (i.e., the calling UE) 201 can first send a "SIP: INVITE" request to a network 203, such as an IMS core network (CN) or evolved universal terrestrial radio access network (EUTRAN). The IMS CN / EUTRAN 203 can route the "SIP: INVITE" request to the MT UE (i.e., the called UE) 202. The "SIP: INVITE" request includes a session description protocol (SDP) offer which includes required media information for the VoLTE call, such as remote IP and port information, IMS media capability information, codec information, bandwidth information, and the like.

[0030] To acknowledge the "SIP: INVITE" request, the MT UE 202 can send a "SIP: 100 Trying" message. The MT UE 202 can further send a "SIP: 183 Session in Progress" message in response to the "SIP: INVITE" request. The "SIP: 183 Session in Progress" message includes an SDP answer which includes local IP and port information and indicates that preconditions for the VoLTE call are not met yet (so not ringing as of now) at the MT UE 202. During routing the SDP answer, the network 203 can activate dedicated EPS bearers for both the MO UE 201 andthe MT UE 202. The details of the dedicated EPS bearer activation have been described in the VoLTE call flow 100 in FIG. 1.

[0031] To acknowledge the "SIP: 183 Session in Progress" message, the MO UE 201 can send a provisional response acknowledge (PRACK) message "SIP: PRACK". To acknowledge the "SIP: PRACK" message, the MT UE 202 can send a "SIP: 200 OK for PRACK" message. Then, the MT UE 202 can start to ring and reply back with a "SIP: 180 Ringing" message. If the MT UE 202 answers the call, the MT UE 202 can further respond with a "SIP: 200 OK" message.

[0032] After the MT UE 202 answers the call, the VoLTE call establishment procedure 200 can enter the call active phase 220, and the MO UE 201 can send a "SIP: ACK" message to show that the VoLTE call has been established. The voice traffic of the VoLTE call can go over the dedicated EPS bearer between the MO UE 201 and the network 203 and the dedicated EPS bearer between the network 203 and the MT UE 202 using a bidirectional real-time transport protocol (RTP).

[0033] After the VoLTE call is ended, there are two cases to handle the dedicated EPS bearer. In a normal case, as shown in FIG. 3A, the network 203 can deactivate the dedicated EPS bearer by sending a "DEACTIVATE EPS BEARER CONTEXT REQUEST" message to the UE 201 (or 202). Upon receipt of the "DEACTIVATE EPS BEARER CONTEXT REQUEST" message, the UE 201 (or 202) can clear the TFT and respond to the network 203 by sending a "DEACTIVATE EPS BEARER CONTEXT ACCEPT" message to the network 203. However, in an abnormal case, as shown in FIG. 3B, the network 203 does not deactivate the dedicated EPS bearer after the VoLTE call is ended. That is, the dedicated bearer is still active or unreleased after the VoLTE call is ended. Accordingly, when the UE 201 9or 202) wants to make or answer a next VoLTE call, the network 203 fails to set up a new dedicated EPS bearer or to modify the unreleased dedicated EPS bearer, and thus the next VoLTE call cannot be successfully established.

[0034] This disclosure provides embodiments of handling an unreleased (or a useless) dedicated EPS bearer. According to aspects of the disclosure, the unreleased dedicated EPS bearer is an active EPS bearer that is not being used by any IMS application of a UE (e.g., the UE 201 or 202). Accordingly, in an embodiment, when the UE does not have any ongoing IMS application (e.g., a VoLTE call), the UE can detect whether there is any active dedicated EPSbearer between the UE and an IMS PDN (e.g., the network 203). If the UE detects an active dedicated EPS bearer existing between the UE and the IMS PDN, the UE can determine that the active dedicated EPS bearer is an unreleased dedicated EPS bearer.

[0035] In an embodiment, the UE can detect an unreleased dedicated EPS bearer based on a packet fdter of a traffic flow template (TFT) of the UE. The traffic flow template is a set of packet filters that is used to map a service data flow to a specific EPS bearer.

[0036] FIG. 4A shows an example of the traffic flow template information element (IE). As shown in FIG. 4A, the traffic flow template information element specifies TFT parameters and operations, such as TFT information element identifier (IEI), a length of the TFT information element, TFT code, the number of packet filters, a packet filter list, and a parameter list.

[0037] FIG. 4B shows an example of the TFT code. FIG. 4C shows an example of the packet filter list. The packet filter list can include one or more packet filters each being identified by a respective packet filter identifier. A packet filter typically includes IP 5-tuples, i.e., source IP address, destination IP address, source port, destination port, and protocol type. A service data packet can be mapped to a dedicated EPS bearer based on the IP 5-tuples included in a packet filter associated with the dedicated EPS bearer. A packet filter can be applied in a downlink direction, an uplink direction, or both directions. A downlink packet filter can be applied by the network and an uplink packet filter can be applied by the UE. A packet filter that applies for both directions can be applied by the network as a downlink packet filter and by the UE as an uplink packet filter.

[0038] According to embodiments of the disclosure, the UE can detect an unreleased dedicated EPS bearer based on a packet filter of a TFT of the UE. In an embodiment, if the UE detects that a packet filter of the TFT is not being used by any IMS application, the UE can determine that a dedicated EPS bearer associated with the packet filter is an unreleased dedicated EPS bearer. Specifically, the UE can detect whether IP and / or port information included in a packet filter is being used by any IMS application. If the UE detects that the IP and / or port information included in the packet filter is not being used by any IMS application, the UE can determine that a dedicated EPS bearer associated with the packet filter is an unreleased dedicated EPS bearer.

[0039] In an embodiment, the UE can detect whether there is any data going through (or matching) a packet filter of the TFT within a predefined period of time. If the UE detects that there is no data going through the packet filter within the predefined period of time, the UE can determine that a dedicated EPS bearer associated with the packet filter is an unreleased dedicated EPS bearer.

[0040] According to aspects of the disclosure, after the UE detects the unreleased dedicated EPS bearer, the UE can deactivate the unreleased dedicated EPS bearer so that a new dedicated EPS bearer can be setup between the UE and the network for a next VoLTE call, or the UE can modify the unreleased dedicated EPS bearer so that the modified dedicated EPS bearer can be used for the next VoLTE call.

[0041] In an embodiment, the UE can trigger a bearer resource modification procedure to request a network to deactivate or modify the unreleased dedicated EPS bearer.

[0042] FIGS. 5A-5C show three examples of handling the unreleased dedicated EPS bearer by triggering a bearer resource modification procedure according to embodiments of the disclosure.

[0043] In FIG. 5 A, the UE 201 (or 202) can send to the network 203 a "BEARERRESOURCE MODIFICATION REQUEST" message including a TFT operation code "Delete packet filters from existing TFT" with all existing packet filters. In response to the TFT operation code "Delete packet filters from existing TFT" with all existing packet filters, the network 203 can delete all existing packet filters from the existing TFT, so that the unreleased dedicated EPS bearer can be deactivated at the network side. The network 203 can then send to the UE 201 (or 202) a "DEACTIVATE EPS BEARER CONTEXT REQUEST" message including an EBI of the unreleased dedicated EPS bearer. Upon receipt of the "DEACTIVATE EPS BEARER CONTEXT REQUEST" message, the UE 201 (or 202) can deactivate the unreleased dedicated EPS bearer based on the EBI of the unreleased dedicated EPS bearer. After deactivating the unreleased dedicated EPS bearer, the UE 201 (or 202) can respond to the network 203 by sending a "DEACTIVATE EPS BEARER CONTEXT ACCEPT" message to the network 203.

[0044] In FIG. 5B, the UE 201 (or 202) can send to the network 203 a "BEARER RESOURCE MODIFICATION REQUEST" message including a TFT operation code "Delete packet filters from existing TFT" with the packet filter associated with the unreleased dedicatedEPS bearer. In response to the TFT operation code "Delete packet filters from existing TFT" with the packet filter associated with the unreleased dedicated EPS bearer, the network 203 can delete the packet filter associated with the unreleased dedicated EPS bearer from the existing TFT, so that the unreleased dedicated EPS bearer can be deactivated at the network side. The network 203 can then send to the UE 201 (or 202) a "MODIFY EPS BEARER CONTEXT REQUEST" message including the TFT operation code "Delete packet filters from existing TFT" with the packet filter associated with the unreleased dedicated EPS bearer. Upon receipt of the "MODIFY EPS BEARER CONTEXT REQUEST" message including the TFT operation code "Delete packet filters from existing TFT" with the packet filter associated with the unreleased dedicated EPS bearer, the UE 201 (or 202) can delete the packet filter associated with the unreleased dedicated EPS bearer from the existing TFT to deactivate the unreleased dedicated EPS bearer. After deactivating the unreleased dedicated EPS bearer, the UE 201 (or 202) can respond to the network 203 by sending a "MODIFY EPS BEARER CONTEXT ACCEPT" message to the network 203.

[0045] In FIG. 5C, the UE 201 (or 202) can remain the unreleased dedicated EPS bearer after the end of the VoLTE call. Once a next VoLTE call is coming, the UE 201 (or 202) can check whether the IP and port information of the packet filter associated with the unreleased dedicated EPS bearer matches the IP and port information carried in the SDP offer and answer of the next call. If not matched, the UE 201 (or 202) can trigger a bearer resource modification procedure to modify the IP and port information of the packet filter to correct the TFT setting. To trigger the bearer resource modification procedure, the UE 201 (or 202) can send to the network 203 a "BEARER RESOURCE MODIFICATION REQUEST" message including a TFT operation code "Replace packet filters in existing TFT" with the correct IP and port information carried in the SDP offer and answer. In response to the TFT operation code "Replace packet filters in existing TFT" with the correct IP and port information carried in the SDP offer and answer, the network 203 can replace the IP and port information of the packet filter associated with the unreleased dedicated EPS bearer with the correct IP and port information carried in the SDP offer and answer, so that the packet filter associated with the unreleased dedicated EPS bearer has been modified at the network side to be used for the coming VoLTE call. The network 203 can then send to the UE 201 (or 202) a "MODIFY EPS BEARER CONTEXTREQUEST" message including the TFT operation code "Replace packet filters in existing TFT" with the correct IP and port information carried in the SDP offer and answer.

[0046] Upon receipt of the "MODIFY EPS BEARER CONTEXT REQUEST" message including the TFT operation code "Replace packet filters in existing TFT" with the correct IP and port information carried in the SDP offer and answer, the UE 201 (or 202) can replace the IP and port information of the packet filter associated with the unreleased dedicated EPS bearer with the correct IP and port information carried in the SDP offer and answer, so that the packet filter associated with the unreleased dedicated EPS bearer has been modified at the UE side to be used for the coming VoLTE call. After modifying the unreleased dedicated EPS bearer, the UE 201 (or 202) can respond to the network 203 by sending a "MODIFY EPS BEARER CONTEXT ACCEPT" message to the network 203.

[0047] In an embodiment, the UE 201 (or 202) can locally release the unreleased dedicated EPS bearer. That is, in contrast to FIGS. 5A-5C, the UE 201 (or 202) can release the unreleased dedicated EPS bearer without receiving an instruction or request message (e.g., the “DEACTIVATE EPS BEARER CONTEXT REQUEST” message or the “MODIFY EPS BEARER CONTEXT ACCEPT” message) from the network 203. After releasing the unreleased dedicated EPS bearer, the UE 201 (or 202) can trigger a tracking area update procedure to indicate to the network 203 that the unreleased dedicated EPS bearer has been released by the UE 201 (or 202).

[0048] FIG. 6 shows an example of locally releasing the unreleased dedicated EPS bearer according to an embodiment of the disclosure. In FIG. 6, the UE 201 (or 202) can first locally release the unreleased dedicated EPS bearer (with an EBI of "x") and then send to the network 203 a "TRACKING AREA UPDATE REQUEST" message including EPS bearer context status information element (IEI). The EPS bearer context status IEI can inform the network 203 that the status of the unreleased dedicated EPS bearer is inactive now, indicating that the unreleased dedicated EPS bearer has been released by the UE 201 (or 202). Upon receipt of the "TRACKING AREA UPDATE REQUEST" message, the network 203 can respond to the UE 201 (or 202) by sending a "TRACKING AREA UPDATE ACCEPT" message.

[0049] In an embodiment, the UE 201 (or 202) can locally release the unreleased dedicated EPS bearer by locally releasing the connection to the IMS PDN. Then, the UE 201 (or202) can trigger a tracking area update procedure to indicate the network 203 that the unreleased dedicated EPS bearer has been released by the UE 201 (or 202).

[0050] FIG. 7 shows an example of locally releasing the connection to the IMS PDN according to an embodiment of the disclosure. In FIG. 7, the UE 201 (or 202) can first locally release the connection to the IMS PDN and then send to the network 203 a "TRACKING AREA UPDATE REQUEST" message including EPS bearer context status IEI. The EPS bearer context status IEI can inform the network 203 that the status of the unreleased dedicated EPS bearer is inactive now, indicating that the unreleased dedicated EPS bearer has been released by the UE 201 (or 202). Upon receipt of the "TRACKING AREA UPDATE REQUEST" message, the network 203 can respond to the UE 201 (or 202) by sending a "TRACKING AREA UPDATE ACCEPT" message.

[0051] In an embodiment, the UE 201 (or 202) can initiate a PDN disconnection procedure to deactivate the unreleased dedicated EPS bearer. FIG. 8 shows an example of deactivating the unreleased dedicated EPS bearer by triggering a PDN disconnection procedure according to an embodiment of the disclosure. In FIG. 8, in order to request the PDN disconnection from the PDN, the UE 201 (or 202) can send to the network 203 a "PDN DISCONNECT REQUEST" message. The "PDN DISCONNECT REQUEST" message can include the EBI of the unreleased dedicated EPS bearer. Upon receipt of the "PDN DISCONNECT REQUEST" message, the network 203 can initiate a bearer context deactivation procedure by sending to the UE 201 (or 202) a "DEACTIVATE EPS BEARER CONTEXT REQUEST" message. The "DEACTIVATE EPS BEARER CONTEXT REQUEST" message includes the EBI of the unreleased dedicated EPS bearer. On receipt of the "DEACTIVATE EPS BEARER CONTEXT REQUEST" message, the UE 201 (or 202) can deactivate the unreleased dedicated EPS bearer identified by the EBI. After deactivating the unreleased dedicated EPS bearer, the UE 201 (or 202) can respond to the network 203 by sending a "DEACTIVATE EPS BEARER CONTEXT ACCEPT" message to the network. Then, the UE 201 (or 202) can re-establish a connection to the IMS PDN by sending to the network 203 a "PDN CONNECTIVITY REQUEST" message. After re-establishing the connection to the IMS PDN, the UE 201 (or 202) can perform an IMS registration. In an example, if the connection to the IMS PDN in the PDN disconnection procedure is a last PDN connection over the LTEnetwork for the UE 201 (or 202), the UE 201 (or 202) needs to re-attach to the IMS PDN before re-establishing the connection to the IMS PDN.

[0052] FIG. 9 shows a flowchart outlining a process 900 according to embodiments of the disclosure. In various embodiments, the process 900 can be executed by processing circuitry, such as the processing circuitry 1010 in the apparatus 1000. For example, the process 900 can be implemented in software instructions, and, when the processing circuitry 1010 executes the software instructions, the processing circuitry 1010 can perform the process 900.

[0053] The process 900 may generally start at step S910, where the process 900 detects an active dedicated EPS bearer between the apparatus 1000 and a PDN. Then, the process 900 can proceed to step S920.

[0054] At step S920, the process 900 can determine whether the active dedicated EPS bearer is being used by an IMS application of the apparatus 1000. In response to determining that the active dedicated EPS bearer is not being used by the IMS application, the process 900 can proceed to step S930.

[0055] At step S930, the process 900 can perform a deactivation or modification operation on the active dedicated EPS bearer.

[0056] In an embodiment, the process 900 can deactivate or modify the active dedicated EPS bearer based on receiving a request message from the PDN.

[0057] In an example, the request message can be the "DEACTIVATE EPS BEARER CONTEXT REQUEST" message in FIG. 5A or FIG. 8. The "DEACTIVATE EPS BEARER CONTEXT REQUEST" message can include an EBI of the active dedicated EPS bearer. Based on the EBI, the process 900 can deactivate the active dedicated EPS bearer. In order to receive the "DEACTIVATE EPS BEARER CONTEXT REQUEST" message, the process 900 can initiate a bearer resource modification procedure of FIG. 5 A or a PDN disconnect procedure of FIG. 8. To initiate the bearer resource modification procedure of FIG. 5A, the process 900 can send to the PDN a "BEARER RESOURCE MODIFICATION REQUEST" message including a TFT operation code "Delete packet filters from existing TFT" with all existing packet filters. To initiate the PDN disconnect procedure of FIG. 8, the process 900 can send to the PDN a “PDN DISCONNECT REQUEST” message.

[0058] In an example, the request message can be the "MODIFY EPS BEARER CONTEXT REQUEST" message in FIG. 5B or FIG. 5C. In FIG. 5B, the "MODIFY EPSBEARER CONTEXT REQUEST" message can include a TFT operation code "Delete packet filters from existing TFT" with a packet filter associated with the active dedicated EPS bearer. Upon receipt of the TFT operation code of FIG. 5B, the process 900 can delete the packet filter associated with the active dedicated EPS bearer from a TFT of the UE, so that the active dedicated EPS bearer can be deactivated. In FIG. 5C, the "MODIFY EPS BEARER CONTEXT REQUEST" message can include a TFT operation code "Replace packet filters in existing TFT" with correct IP and port information. Upon receipt of the TFT operation code of FIG. 5C, the process 900 can modify the packet filter associated with the active dedicated EPS bearer by replacing the IP and port information of the packet filter with the correct IP and port information, so that the modified packet filter and the modified active dedicated EPS bearer can be used for a next VoLTE call.

[0059] In an embodiment, the process 900 can deactivate the active dedicated EPS bearer without receiving a request message from the PDN. For example, as shown in FIG. 6, the process 900 can locally release the active dedicated EPS bearer without receiving a request message from the PDN. Alternatively, as shown in FIG. 7, the process 900 can locally release a connection to the PDN without receiving a request message from the PDN, resulting in the deactivation of the active dedicated EPS bearer. In both examples, after locally releasing the active dedicated EPS bearer, the process 900 can send to the PDN a "TRACKING AREA UPDATE REQUEST" message indicating that the active dedicated EPS bearer has been released.

[0060] FIG. 10 shows an apparatus 1000 according to embodiments of the disclosure. The apparatus 1000 can be configured to perform various functions in accordance with one or more embodiments or examples described herein. Thus, the apparatus 1000 can provide the implementation of techniques, processes, functions, components, and systems described herein. For example, the apparatus 1000 can be used to implement functions of a UE or a base station (BS) (e.g., gNB) in various embodiments and examples described herein. The apparatus 1000 can include a processor or specially designed circuits to implement various functions, components, or processes described herein in various embodiments. The apparatus 1000 can include processing circuitry 1010, a memory 1020, a radio frequency (RF) module 1030, and an antenna 1040.

[0061] In various examples, the processing circuitry 1010 can include one or more circuits configured to perform the functions and processes described herein in combination with software or without software. In various examples, the processing circuitry 1010 can be a digital signal processor (DSP), an application specific integrated circuit (ASIC), programmable logic devices (PLDs), field programmable gate arrays (FPGAs), digitally enhanced circuits, or comparable device(s) or a combination thereof

[0062] In some examples, the processing circuitry 1010 or circuitry can be a central processing unit (CPU) configured to execute program instructions to perform various functions and processes described herein. Accordingly, the memory 1020 can be configured to store program instructions. The processing circuitry 1010, when executing the program instructions, can perform the functions and processes. The memory 1020 can further store other programs or data, such as operating systems, application programs, and the like. The memory 1020 can include a read only memory (ROM), a random access memory (RAM), a flash memory, a solid state memory, a hard disk drive, an optical disk drive, and the like.

[0063] The RF module 1030 can receive a processed data signal from the processing circuitry 1010 and convert the data signal to beamforming wireless signals that are then transmitted via the antenna 1040, or vice versa. The RF module 1030 can include a digital to analog convertor (DAC), an analog to digital converter (ADC), a frequency up convertor, a frequency down converter, filters and amplifiers for reception and transmission operations. The RF module 1030 can include multi-antenna circuitry for beamforming operations. For example, the multiantenna circuitry can include an uplink spatial filter circuit, and a downlink spatial filter circuit for shifting analog signal phases or scaling analog signal amplitudes. The antenna 1040 can include one or more antenna arrays.

[0064] The apparatus 1000 can optionally include other components, such as input and output devices, additional or signal processing circuitry, and the like. Accordingly, the apparatus 1000 may be capable of performing other additional functions, such as executing application programs, and processing alternative communication protocols.

[0065] The techniques described above, can be implemented as computer software using computer-readable instructions and physically stored in one or more computer-readable media. For example, FIG. 11 shows a computer system 1100 suitable for implementing certain embodiments of the disclosed subject matter.

[0066] The computer software can be coded using any suitable machine code or computer language, that may be subject to assembly, compilation, linking, or like mechanisms to create code comprising instructions that can be executed directly, or through interpretation, micro-code execution, and the like, by one or more CPUs, Graphics Processing Units (GPUs), and the like.

[0067] The instructions can be executed on various types of computers or components thereof, including, for example, personal computers, tablet computers, servers, smartphones, gaming devices, internet of things devices, and the like.

[0068] The components shown in FIG. 11 for computer system 1100 are exemplary in nature and are not intended to suggest any limitation as to the scope of use or functionality of the computer software implementing embodiments of the present disclosure. Neither should the configuration of components be interpreted as having any dependency or requirement relating to any one or combination of components illustrated in the exemplary embodiment of a computer system 1100.

[0069] Computer system 1100 may include certain human interface input devices. Such a human interface input device may be responsive to input by one or more human users through, for example, tactile input (such as: keystrokes, swipes, data glove movements), audio input (such as: voice, clapping), visual input (such as: gestures), olfactory input (not depicted). The human interface devices can also be used to capture certain media not necessarily directly related to conscious input by a human, such as audio (such as: speech, music, ambient sound), images (such as: scanned images, photographic images obtain from a still image camera), video (such as two-dimensional video, three-dimensional video including stereoscopic video).

[0070] Input human interface devices may include one or more of (only one of each depicted): keyboard 1101, mouse 1102, trackpad 1103, touch screen 1110, data-glove (not shown), joystick 1105, microphone 1106, scanner 1107, and camera 1108.

[0071] Computer system 1100 may also include certain human interface output devices. Such human interface output devices may be stimulating the senses of one or more human users through, for example, tactile output, sound, light, and smell / taste. Such human interface output devices may include tactile output devices (for example tactile feedback by the touch-screen 1110, data-glove (not shown), or joystick 1105, but there can also be tactile feedback devices that do not serve as input devices), audio output devices (such as: speakers 1109, headphones(not depicted)), visual output devices (such as screens 1110 to include CRT screens, LCD screens, plasma screens, OLED screens, each with or without touch-screen input capability, each with or without tactile feedback capability — some of which may be capable to output two dimensional visual output or more than three dimensional output through means such as stereographic output; virtual-reality glasses (not depicted), holographic displays and smoke tanks (not depicted)), and printers (not depicted). These visual output devices (such as screens 1110) can be connected to a system bus 1148 through a graphics adapter 1150.

[0072] Computer system 1100 can also include human accessible storage devices and their associated media such as optical media including CD / DVD ROM / RW 1120 with CD / DVD or the like media 1121, thumb-drive 1122, removable hard drive or solid state drive 1123, legacy magnetic media such as tape and floppy disc (not depicted), specialized ROM / ASIC / PLD based devices such as security dongles (not depicted), and the like.

[0073] Those skilled in the art should also understand that term “computer readable media” as used in connection with the presently disclosed subject matter does not encompass transmission media, carrier waves, or other transitory signals.

[0074] Computer system 1100 can also include a network interface 1154 to one or more communication networks 1155. The one or more communication networks 1155 can for example be wireless, wireline, optical. The one or more communication networks 1155 can further be local, wide-area, metropolitan, vehicular and industrial, real-time, delay -tolerant, and so on. Examples of the one or more communication networks 1155 include local area networks such as Ethernet, wireless LANs, cellular networks to include GSM, 3G, 4G, 5G, LTE and the like, TV wireline or wireless wide area digital networks to include cable TV, satellite TV, and terrestrial broadcast TV, vehicular and industrial to include CANBus, and so forth. Certain networks commonly require external network interface adapters that attached to certain general purpose data ports or peripheral buses 1149 (such as, for example USB ports of the computer system 1100); others are commonly integrated into the core of the computer system 1100 by attachment to a system bus as described below (for example Ethernet interface into a PC computer system or cellular network interface into a smartphone computer system). Using any of these networks, computer system 1100 can communicate with other entities. Such communication can be uni-directional, receive only (for example, broadcast TV), uni -directional send-only (for example CANbus to certain CANbus devices), or bi-directional, for example toother computer systems using local or wide area digital networks. Certain protocols and protocol stacks can be used on each of those networks and network interfaces as described above.

[0075] Aforementioned human interface devices, human-accessible storage devices, and network interfaces can be attached to a core 1140 of the computer system 1100.

[0076] The core 1140 can include one or more CPUs 1141, GPUs 1142, specialized programmable processing units in the form of Field Programmable Gate Areas (FPGA) 1143, hardware accelerators for certain tasks 1144, graphics adapters 1150, and so forth. These devices, along with Read-only memory (ROM) 1145, Random-access memory 1146, internal mass storage 1147 such as internal non-user accessible hard drives, SSDs, and the like, may be connected through the system bus 1148. In some computer systems, the system bus 1148 can be accessible in the form of one or more physical plugs to enable extensions by additional CPUs, GPUs, and the like. The peripheral devices can be attached either directly to the core’s system bus 1148, or through a peripheral bus 1149. In an example, the screen 1110 can be connected to the graphics adapter 1150. Architectures for a peripheral bus include PCI, USB, and the like.

[0077] CPUs 1141, GPUs 1142, FPGAs 1143, and accelerators 1144 can execute certain instructions that, in combination, can make up the aforementioned computer code. That computer code can be stored in ROM 1145 or RAM 1146. Transitional data can also be stored in RAM 1146, whereas permanent data can be stored for example, in the internal mass storage 1147. Fast storage and retrieve to any of the memory devices can be enabled through the use of cache memory, that can be closely associated with one or more CPUs 1141, GPUs 1142, mass storage 1147, ROM 1145, RAM 1146, and the like.

[0078] The computer readable media can have computer code thereon for performing various computer-implemented operations. The media and computer code can be those specially designed and constructed for the purposes of the present disclosure, or they can be of the kind well known and available to those having skill in the computer software arts.

[0079] As an example and not by way of limitation, the computer system having architecture 1100, and specifically the core 1140 can provide functionality as a result of processor(s) (including CPUs, GPUs, FPGA, accelerators, and the like) executing software embodied in one or more tangible, computer-readable media. Such computer-readable media can be media associated with user-accessible mass storage as introduced above, as well as certain storage of the core 1140 that are of non-transitory nature, such as core-internal mass storage1147 or ROM 1145. The software implementing various embodiments of the present disclosure can be stored in such devices and executed by core 1140. A computer-readable medium can include one or more memory devices or chips, according to particular needs. The software can cause the core 1140 and specifically the processors therein (including CPU, GPU, FPGA, and the like) to execute particular processes or particular parts of particular processes described herein, including defining data structures stored in RAM 1146 and modifying such data structures according to the processes defined by the software. In addition or as an alternative, the computer system can provide functionality as a result of logic hardwired or otherwise embodied in a circuit (for example: accelerator 1144), which can operate in place of or together with software to execute particular processes or particular parts of particular processes described herein. Reference to software can encompass logic, and vice versa, where appropriate. Reference to a computer-readable media can encompass a circuit (such as an integrated circuit (IC)) storing software for execution, a circuit embodying logic for execution, or both, where appropriate. The present disclosure encompasses any suitable combination of hardware and software.

[0080] Aspects of the disclosure provide a method of wireless communication at a UE. The method includes detecting an active dedicated EPS bearer between the UE and a PDN, determining whether the active dedicated EPS bearer is being used by an IMS application of the UE, and in response to determining that the active dedicated EPS bearer is not being used by the IMS application, performing a deactivation or modification operation on the active dedicated EPS bearer.

[0081] In an embodiment, the determining includes determining whether a packet filter associated with the active dedicated EPS bearer is being used by the IMS application, and in response to determining that the packet filter associated with the active dedicated EPS bearer is not being used by the IMS application, determining that the active dedicated EPS bearer is not being used by the IMS application.

[0082] In an embodiment, the determining includes determining whether there is data going through a packet filter associated with the active dedicated EPS bearer within a predefined period of time, and in response to determining that there is no data going through the packet filter associated with the active dedicated EPS bearer within the predefined period of time, determining that the active dedicated EPS bearer is not being used by the IMS application.

[0083] In an embodiment, the performing includes sending to the PDN a bearer resource modification request.

[0084] In an embodiment, the bearer resource modification request includes a traffic flow template operation code that instructs the PDN to delete all packet filters from an existing traffic flow template. The performing includes receiving a message from the PDN to deactivate the active dedicated EPS bearer, the message including an EPS bearer identifier of the active dedicated EPS bearer, and deactivating the active dedicated EPS bearer based on the EPS bearer identifier of the active dedicated EPS bearer included in the message.

[0085] In an embodiment, the bearer resource modification request includes a traffic flow template operation code that instructs the PDN to delete a packet filter associated with the active dedicated EPS bearer that is not being used by the IMS application. The performing includes receiving a message from the PDN to delete the packet filter associated with the active dedicated EPS bearer that is not being used by the IMS application, and deleting the packet filter associated with the active dedicated EPS bearer that is into being used by the IMS application.

[0086] In an embodiment, the bearer resource modification request includes a traffic flow template operation code that instructs the PDN to modify a packet filter associated with the active dedicated EPS bearer that is not being used by the IMS application. The performing includes receiving a message from the PDN to modify the packet filter associated with the active dedicated EPS bearer, the message including IP and port information used for modifying the packet filter, and modifying the packet filter associated with the active dedicated EPS bearer based on the IP and port information included in the message.

[0087] In an embodiment, the performing includes releasing the active dedicated EPS bearer, and sending to the PDN a message indicating that the active dedicated EPS bearer has been released by the UE.

[0088] In an embodiment, the performing includes releasing a connection to the PDN, and sending to the PDN a message indicating that the connection to the PDN has been released by the UE.

[0089] In an embodiment, the performing includes sending to the PDN a PDN disconnect request, receiving from the PDN a message to deactivate the active dedicated EPS bearer, and deactivating the active dedicated EPS bearer. The method further includes re-establishing a connection to the PDN, and performing an IMS registration.

[0090] In an embodiment, the IMS application includes a VoLTE call or a ViLTE call.

[0091] Aspects of the disclosure provide an apparatus. The apparatus includes processing circuitry that detects an active EPS bearer between the apparatus and a PDN, determine whether the active dedicated EPS bearer is being used by an IMS application of the apparatus, and in response to determining that the active dedicated EPS bearer is not being used by the IMS application, perform a deactivation or modification operation on the active dedicated EPS bearer.

[0092] In an embodiment, the processing circuitry determines whether a packet filter associated with the active dedicated EPS bearer is being used by the IMS application, and in response to determining that the packet filter associated with the active dedicated EPS bearer is not being used by the IMS application, determines that the active dedicated EPS bearer is not being used by the IMS application.

[0093] In an embodiment, the processing circuitry determines whether there is data going through a packet filter associated with the active dedicated EPS bearer within a predefined period of time, and in response to determining that there is no data going through the packet filter associated with the active dedicated EPS bearer within the predefined period of time, determines that the active dedicated EPS bearer is not being used by the IMS application.

[0094] In an embodiment, the processing circuitry sends to the PDN a bearer resource modification request.

[0095] Aspects of the disclosure provide a non-transitory computer-readable medium storing instructions, which when executed by a processor, cause the processor to perform a method. The method includes detecting an active dedicated EPS bearer between a UE and a PDN, determining whether the active dedicated EPS bearer is being used by an IMS application of the UE, and in response to determining that the active dedicated EPS bearer is not being used by the IMS application, performing a deactivation or modification operation on the active dedicated EPS bearer.

[0096] While this disclosure has described several exemplary embodiments, there are alterations, permutations, and various substitute equivalents, which fall within the scope of the disclosure. It will thus be appreciated that those skilled in the art will be able to devise numerous systems and methods which, although not explicitly shown or described herein, embody the principles of the disclosure and are thus within the spirit and scope thereof.

Claims

WHAT IS CLAIMED IS:

1. A method of wireless communication at a user equipment (UE), the method comprising: detecting an active dedicated evolved packet system (EPS) bearer between the UE and a packet data network (PDN); determining whether the active dedicated EPS bearer is being used by an internet protocol (IP) multimedia subsystem (IMS) application of the UE; and in response to determining that the active dedicated EPS bearer is not being used by the IMS application, performing a deactivation or modification operation on the active dedicated EPS bearer.

2. The method of claim 1, wherein the determining includes: determining whether a packet filter associated with the active dedicated EPS bearer is being used by the IMS application; and in response to determining that the packet filter associated with the active dedicated EPS bearer is not being used by the IMS application, determining that the active dedicated EPS bearer is not being used by the IMS application.

3. The method of claim 1, wherein the determining includes: determining whether there is data going through a packet filter associated with the active dedicated EPS bearer within a predefined period of time; and in response to determining that there is no data going through the packet filter associated with the active dedicated EPS bearer within the predefined period of time, determining that the active dedicated EPS bearer is not being used by the IMS application.

4. The method of claim 1, wherein the performing includes sending to the PDN a bearer resource modification request.

5. The method of claim 4, wherein the bearer resource modification request includes a traffic flow template operation code that instructs the PDN to delete all packet filters from an existing traffic flow template.

6. The method of claim 5, wherein the performing includes: receiving a message from the PDN to deactivate the active dedicated EPS bearer, the message including an EPS bearer identifier of the active dedicated EPS bearer; and deactivating the active dedicated EPS bearer based on the EPS bearer identifier of the active dedicated EPS bearer included in the message.

7. The method of claim 4, wherein the bearer resource modification request includes a traffic flow template operation code that instructs the PDN to delete a packet filter associated with the active dedicated EPS bearer that is not being used by the IMS application.

8. The method of claim 7, wherein the performing includes: receiving a message from the PDN to delete the packet filter associated with the active dedicated EPS bearer that is not being used by the IMS application; and deleting the packet filter associated with the active dedicated EPS bearer that is into being used by the IMS application.

9. The method of claim 4, wherein the bearer resource modification request includes a traffic flow template operation code that instructs the PDN to modify a packet filter associated with the active dedicated EPS bearer that is not being used by the IMS application.

10. The method of claim 9, wherein the performing includes: receiving a message from the PDN to modify the packet filter associated with the active dedicated EPS bearer, the message including IP and port information used for modifying the packet filter; and modifying the packet filter associated with the active dedicated EPS bearer based on the IP and port information included in the message.

11. The method of claim 1, wherein the performing includes: releasing the active dedicated EPS bearer; andsending to the PDN a message indicating that the active dedicated EPS bearer has been released by the UE.

12. The method of claim 1, wherein the performing includes: releasing a connection to the PDN; and sending to the PDN a message indicating that the connection to the PDN has been released by the UE.

13. The method of claim 1, wherein the performing includes: sending to the PDN a PDN disconnect request; receiving from the PDN a message to deactivate the active dedicated EPS bearer; and deactivating the active dedicated EPS bearer.

14. The method of claim 13, further comprising: re-establishing a connection to the PDN; and performing an IMS registration.

15. The method of claim 1, wherein the IMS application includes a voice over long term evolution (VoLTE) call or a video over long term evolution (ViLTE) call.

16. An apparatus, comprising: processing circuitry configured to detect an active dedicated evolved packet system (EPS) bearer between the apparatus and a packet data network (PDN), determine whether the active dedicated EPS bearer is being used by an internet protocol (IP) multimedia subsystem (IMS) application of the apparatus, and in response to determining that the active dedicated EPS bearer is not being used by the IMS application, perform a deactivation or modification operation on the active dedicated EPS bearer.

17. The apparatus of claim 16, wherein the processing circuitry is configured to:determine whether a packet filter associated with the active dedicated EPS bearer is being used by the IMS application; and in response to determining that the packet filter associated with the active dedicated EPS bearer is not being used by the IMS application, determine that the active dedicated EPS bearer is not being used by the IMS application.

18. The apparatus of claim 16, wherein the processing circuitry is configured to: determine whether there is data going through a packet filter associated with the active dedicated EPS bearer within a predefined period of time; and in response to determining that there is no data going through the packet filter associated with the active dedicated EPS bearer within the predefined period of time, determine that the active dedicated EPS bearer is not being used by the IMS application.

19. The apparatus of claim 16, wherein the processing circuitry is configured to send to the PDN a bearer resource modification request.

20. A non-transitory computer-readable medium storing instructions that, when executed by a processor, cause the processor to perform a method, the method comprising: detecting an active dedicated evolved packet system (EPS) bearer between a user equipment (UE) and a packet data network (PDN); determining whether the active dedicated EPS bearer is being used by an internet protocol (IP) multimedia subsystem (IMS) application of the UE; and in response to determining that the active dedicated EPS bearer is not being used by the IMS application, performing a deactivation or modification operation on the active dedicated EPS bearer.

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