Claims:STATEMENT OF CLAIMS
We claim:
1. A method for managing call continuity at a User Equipment (UE), the method comprising:
initiating, by the UE, a RTP timer when a call is active;
detecting, by the UE, when the RTP timer exceeds a RTP timeout threshold; and
sending, by the UE, a message to a network entity to trigger a handover procedure before the RTP timer expires.
2. The method of claim 1, wherein the message comprises a remaining time period for the RTP timer to get expired.
3. The method of claim 1, wherein the message is at least one of a measurement report message, a Session Initiation Protocol (SIP) UPDATE message, and a SIP INFO message.
4. The method of claim 1, wherein the call is one of: a voice call, an emergency call, an internet protocol (IP) Multimedia Subsystem (IMS) Call, and a video call over one of: a Long-Term Evolution (LTE) network and a High Speed Packet Access (HSPA) network.
5. The method of claim 1, wherein the RTP timeout threshold is defined by one of an IP Multimedia Subsystem (IMS) of the UE and the network entity.
6. The method of claim 1, wherein the network entity is at least one of an eNodeB, an IP Multimedia Subsystem server, and a Mobility Management Entity.
7. The method of claim 1, wherein the RTP timer is a RTP control Protocol Timer to monitor a downlink packet reception at the UE.
8. A method for managing a call continuity at a User Equipment (UE), the method comprising:
receiving, by a network entity, a message when said call is active at said UE, wherein said message comprises a remaining time period for a RTP timer to get expired at said UE; and
triggering, by said network entity, a handover procedure before said RTP timer expires for continuing said call at said UE.
9. The method of claim 8, wherein said network entity transfers said call from a source cell to a new target cell during said handover procedure.
10. The method of claim 9, wherein said network entity selects said target cell based on a measurement report received from said source cell, wherein said measurement report for said target cell is configured based on said remaining time period for said RTP timer to get expired at said UE.
11. The method of claim 8, wherein said message is one of a measurement report message, a Session Initiation Protocol (SIP) UPDATE message, and a SIP INFO message.
12. The method of claim 8, wherein said call is one of: a voice call, an emergency call, an internet protocol (IP) Multimedia Subsystem (IMS) Call, and a video call over one of: a Long-Term Evolution (LTE) network and a High Speed Packet Access (HSPA) network.
13. The method of claim 8, wherein said network entity is at least one of an eNodeB, an IP Multimedia Subsystem server, and a Mobility Management Entity.
14. The method of claim 8, wherein said RTP timer is a RTP control Protocol Timer to monitor a downlink packet reception at said UE.
15. A User Equipment (UE) for managing a call continuity, the UE is configured to comprising:
initiate a RTP timer when said call is active; and detect said RTP timer exceeds a RTP timeout threshold; and
send a message to a network entity to trigger a handover procedure before said RTP timer expires for continuing said call.
16. The UE of claim 15, wherein said message comprises a remaining time period for said RTP timer to get expired.
17. The UE of claim 15, wherein said message is one of a measurement report message, a Session Initiation Protocol (SIP) UPDATE message, and a SIP INFO message.
18. The UE of claim 15, wherein said call is one of: a voice call, an emergency call, an internet protocol (IP) Multimedia Subsystem (IMS) Call, and a video call over one of: a Long-Term Evolution (LTE) network and a High Speed Packet Access (HSPA) network.
19. The UE of claim 15, wherein said RTP timeout threshold is defined by one of an IP Multimedia Subsystem (IMS) of said UE and said network entity.
20. The UE of claim 15, wherein said network entity is at least one of an eNodeB, an IP Multimedia Subsystem server, and a Mobility Management Entity.
21. The UE of claim 15, wherein said RTP timer is a RTP control Protocol Timer to monitor a downlink packet reception at said UE.
22. A network entity for managing a call continuity at a User Equipment (UE), the network entity comprising:
a memory;
a processor, couple to said memory, configured to:
receive, by a network entity, a message when said call is active at said UE, wherein said message comprises a remaining time period for said RTP timer to get expired at said UE; and
trigger, by said network entity, a handover procedure before said RTP timer expires for continuing said call at said UE.
23. The network entity of claim 22, wherein said network entity transfers said call from a first channel to a second channel during said handover procedure.
24. The network entity of claim 23, wherein said network entity selects said second channel based on a measurement report received from said second channel, wherein said measurement report for said second channel is configured based on said remaining time period for said RTP timer to get expired at said UE.
25. The network entity of claim 22, wherein said message is one of a measurement report message and a Session Initiation Protocol (SIP) UPDATE message, and a SIP INFO message.
26. The network entity of claim 22, wherein said call is one of: a voice call, an emergency call, an internet protocol (IP) Multimedia Subsystem (IMS) Call, and a video call over one of: a Long-Term Evolution (LTE) network and a High Speed Packet Access (HSPA) network.
27. The network entity of claim 22, wherein said network entity is at least one of an eNodeB, an IP Multimedia Subsystem server, and a Mobility Management Entity.
28. The network entity of claim 22, wherein said RTP timer is a RTP control Protocol Timer to monitor a downlink packet reception at said UE.
Dated: 22nd Day of December, 2015 Signature
Arun Kishore Narasani Patent Agent
, Description:FIELD OF INVENTION
[0001] The present disclosure relates to a communication system, and more particularly to a mechanism for managing call continuity at a User Equipment (UE).
BACKGROUND OF INVENTION
[0002] The Long Term Evolution (LTE) standard is a standard for wireless communication of high-speed data for a User Equipment (UE). The LTE network is being co-deployed in overlapping regions with legacy cellular network so that the UE may transition between cellular radio access technologies (RATs) as a result of moving in and out of LTE coverage. In the LTE network, the UE can support a Voice over LTE (VoLTE) call. During the VoLTE call, downlink (DL) packets might be lost before reaching to a Real-time Transport Protocol (RTP) layer/RTP Control Protocol (RTCP) in the UE. The packet loss might occur due to various reasons such as High Block Error Rate (BLER), L2TX Retransmission and L2RX Discards, poor Carrier to Interference-plus-Noise Ratio (CINR) Ratio, Robust Header Compression (RoHC) state mismatch between the UE and an eNodeB, a RoHC Decompression Error, Intra and inter-eNodeB handover (HO) failure, or the like.
[0003] The UE starts a RTP/RTCP timer to monitor a Downlink (DL) Internet Protocol (IP) Multimedia Subsystem (IMS) voice/video packet reception and the RTP/RTCP timer is restarted every time a new DL VoLTE packet is received. If the RTP/RTCP timer expires, a BYE message is triggered from the UE. This results in dropping the VoLTE call in the network as shown in FIG. 1.
[0004] Thus, it is desired to address the above mentioned disadvantages or other shortcomings or at least provide a useful alternative to prevent the VoLTE call drop so as to improve the user experience.

OBJECT OF INVENTION
[0005] The principal object of the embodiments herein is to provide a method for managing call continuity at a User Equipment (UE).
[0006] Another object of the embodiments herein is to provide a mechanism for detecting a RTP/RTCP timer exceeds a timeout threshold.
[0007] Another object of the embodiments herein is to provide a mechanism for sending a measurement report message to a network entity to trigger a handover procedure before a RTP/RTCP timer expires, where the measurement report includes a remaining time period for the RTP/RTCP timer to get expired.
[0008] Another object of the embodiments herein is to provide a mechanism for sending a SIP UPDATE message to a network entity to trigger a handover procedure before a RTP/RTCP timer expires, where the SIP UPDATE message includes a remaining time period for the RTP/RTCP timer to get expired.
[0009] Another object of the embodiments herein is to provide a mechanism for sending a SIP INFO message to a network entity to trigger a handover procedure before a RTP/RTCP timer expires, where the SIP INFO message includes a remaining time period for the RTP/RTCP timer to get expired.
[0010] Another object of the embodiments herein is to provide a mechanism for selecting a target cell based on the remaining timer value in the message.
SUMMARY
[0011] The embodiments herein disclose a method for managing call continuity at a User Equipment (UE). The method includes initiating, at a UE, a RTP/RTCP timer for monitoring a DL packet reception when the IMS call is active. Further, the method includes detecting the RTP/RTCP timer exceeds a RTP/RTCP timeout threshold. Furthermore, the method includes sending, by the UE, a message to a network entity to trigger a handover procedure before the RTP/RTCP timer expires for continuing the call.
[0012] The embodiments herein disclose a method for managing call continuity at a User Equipment (UE). The method includes receiving, by a network entity, a message when the call is active at the UE. The message includes a remaining time period for said RTP/RTCP timer to get expired at the UE. Further, the method includes triggering, by the network entity, a handover procedure before the RTP/RTCP timer expires for continuing the call at the UE.
[0013] The embodiments herein disclose a User Equipment (UE) for managing call continuity. The UE is configured to initiate a RTP/RTCP timer for monitoring a DL packet reception when the call is active. The UE is configured to detect the RTP/RTCP timer exceeds a RTP/RTCP timeout threshold. The UE is configured to send a message to a network entity to trigger a handover procedure before the RTP/RTCP timer expires for continuing the call.
[0014] The embodiments herein disclose a network entity for managing call continuity at a User Equipment (UE). The network entity includes a processor couple to a memory. The processor is configured to receive a message when the call is active at the UE. The message includes a remaining time period for the RTP/RTCP timer to get expired at the UE. The processor is configured to trigger a handover procedure before the RTP/RTCP timer expires for continuing the call at the UE.
[0015] These and other aspects of the embodiments herein will be better appreciated and understood when considered in conjunction with the following description and the accompanying drawings. It should be understood, however, that the following descriptions, while indicating preferred embodiments and numerous specific details thereof, are given by way of illustration and not of limitation. Many changes and modifications may be made within the scope of the embodiments herein without departing from the spirit thereof, and the embodiments herein include all such modifications.
BRIEF DESCRIPTION OF FIGURES
[0016] This invention is illustrated in the accompanying drawings, throughout which like reference letters indicate corresponding parts in the various figures. The embodiments herein will be better understood from the following description with reference to the drawings, in which:
[0017] FIG. 1 is a sequence diagram illustrating a VoLTE call drop scenario, according to prior art;
[0018] FIG. 2 is a sequence diagram illustrating a VoLTE call continuity scenario, according to embodiments as disclosed herein;
[0019] FIG. 3 illustrates various units of a UE, according to embodiments as disclosed herein;
[0020] FIG. 4 illustrates various units of a network entity, according to embodiments as disclosed herein;
[0021] FIG. 5 is a flow diagram illustrating a method for managing a call continuity at a UE, according to embodiments as disclosed herein;
[0022] FIG. 6 is a sequence flow diagram illustrating a measurement report based handover scenario to manage a call continuity at a UE, according to an embodiment as disclosed herein;
[0023] FIG. 7 is a sequence flow diagram illustrating a SIP UPDATE message based handover scenario to manage a call continuity at a UE, according to an embodiment as disclosed herein;
[0024] FIG. 8 is a sequence flow diagram illustrating a SIP INFO message based handover scenario to manage a call continuity at a UE, according to an embodiment as disclosed herein;
[0025] FIG. 9 is a sequence flow diagram illustrating network side operations to perform a handover to manage a call continuity at a UE, according to an embodiment as disclosed herein; and
[0026] FIG. 10 illustrates a computing environment implementing a mechanism for managing call continuity at a UE, according to an embodiment as disclosed herein.

DETAILED DESCRIPTION OF INVENTION
[0027] The embodiments herein and the various features and advantageous details thereof are explained more fully with reference to the non-limiting embodiments that are illustrated in the accompanying drawings and detailed in the following description. Descriptions of well-known components and processing techniques are omitted so as to not unnecessarily obscure the embodiments herein. Also, the various embodiments described herein are not necessarily mutually exclusive, as some embodiments can be combined with one or more other embodiments to form new embodiments. The term “or” as used herein, refers to a non-exclusive or, unless otherwise indicated. The examples used herein are intended merely to facilitate an understanding of ways in which the embodiments herein can be practiced and to further enable those skilled in the art to practice the embodiments herein. Accordingly, the examples should not be construed as limiting the scope of the embodiments herein.
[0028] The embodiments herein achieve a method for managing call continuity at a User Equipment (UE). The method includes initiating a RTP/RTCP timer to monitor the DL VoLTE packet reception when the call is active. Further, the method includes detecting the RTP/RTCP timer exceeds a RTP/RTCP timeout threshold; and sending a message to a network entity to trigger a handover procedure before the RTP/RTCP timer expires for continuing the call.
[0029] In an embodiment, the message includes a remaining time period to expire the RTP timer.
[0030] In an embodiment, the message is a measurement report message.
[0031] In an embodiment, the message is a Session Initiation Protocol (SIP) UPDATE message.
[0032] In an embodiment, the message is a SIP INFO message.
[0033] In an embodiment, the call is an IMS voice call over LTE.
[0034] In an embodiment, the call is an IMS video call over LTE.
[0035] In an embodiment, the call is an IMS emergency call over LTE.
[0036] In an embodiment, the call is an IMS voice call over a HSPA.
[0037] In an embodiment, the call is an IMS video call over the HSPA.
[0038] In an embodiment, the call is an IMS emergency call over the HSPA.
[0039] In an embodiment, the RTP/RTCP timeout threshold is defined by an Internet protocol (IP) Multimedia Subsystem (IMS) of the UE.
[0040] In an embodiment, the RTP/RTCP timeout threshold is defined by the network entity.
[0041] In an embodiment, the RTP/RTCP timer is used to monitor a downlink voice or video data packet reception at the UE.
[0042] In an embodiment, the network entity selects a target cell based on the message received from a source cell. The message for the target cell is configured based on the remaining time period for the RTP/RTCP timer to get expired at the UE.
[0043] The embodiments herein achieve a UE for managing call continuity. The UE includes an IP Multimedia Subsystem configured to initiate a RTP/RTCP for monitoring a DL packet reception timer when the call is active. The IP Multimedia Subsystem is configured to detect the RTP/RTCP timer exceeds a RTP/RTCP timeout threshold. A Radio Resource Control (RRC) unit is configured to send a message to a network entity to trigger a handover procedure before the RTP/RTCP timer expires for continuing the call.
[0044] The embodiments herein achieve a network entity for managing call continuity at the UE. The network entity includes a processor couple to a memory. The processor is configured to receive a message when the call is active at the UE. Unlike the conventional systems and methods, the message includes a time period remained to expire a RTP/RTCP timer at the UE. The processor is configured to trigger a handover procedure before the RTP/RTCP timer expires for continuing the call at the UE.
[0045] Unlike the conventional systems and methods, a RTP/RTCP layer can indicate the RTP/RTCP timer status to a LTE RRC layer triggering the UE to send the measurement report to the network with RTP/RTCP timeout indication/value. Based on the RTP/RTCP timeout indication/value, the network can trigger the intra-LTE HO or the SRVCC HO to 3G/2G.
[0046] In existing systems and methods, all measurements reported by the RRC layer are generally based on physical layer measurements. The RRC layer does not distinguish between the VoLTE call and a file transfer protocol (FTP) session. The VoLTE call has more sensitive quality of service (QOS) compared to the FTP. This results in dropping call. Unlike conventional systems and methods, the proposed method sends the measurement report to the network to trigger the handover procedure before the RTP/RTCP timer expires for continuing the call. This results in ensuring the VoLTE call continuity and enhancing the user experience.
[0047] The RTP/RTCP layer indicates the RTP/RTCP timer status to an Internet Protocol multimedia subsystem application processor (IMS-AP) server which in turn may initiate intra-LTE HO or SRVCC to 2G/3G so that the call can successfully continue in the 2G or 3G.This results in ensuring the VoLTE call continuity and enhancing the user experience.
[0048] Referring now to the drawings and more particularly to FIGS. 2 through 10, where similar reference characters denote corresponding features consistently throughout the figure, there are shown preferred embodiments.
[0049] FIG. 2 is a sequence diagram illustrating a VoLTE call continuity scenario in a UE 102, according to embodiments as disclosed herein. The UE 102 can be, for example but not limited to, a cellular phone, a tablet, a smart phone, a laptop, a personal digital assistant (PDA), a satellite radio, a global positioning system, a multimedia device, a video device, a game console, or the like. The UE 102 may also be referred to by those skilled in the art as a mobile station, a subscriber station, a mobile unit, a subscriber unit, a wireless unit, a remote unit, a mobile device, a wireless device, a wireless communications device, a mobile subscriber station, an access terminal, a mobile terminal, a wireless terminal, a remote terminal, a handset, a user agent, a mobile client, or the like. The UE 102 is compliant with multiple, different communication protocols that can operate as a multi-mode device by communicating within a fourth generation (4G) network employing any common type of LTE or LTE-Advanced (LTE-A) radio access technology (RAT), as well as within a third generation (3G) or second generation2G network employing any common type of legacy RAT.
[0050] In an embodiment, consider that an active call is going on at the UE 102. The call is a Voice or a Video or Emergency IMS Call over LTE or the HSPA. If the UE 102 does not receive the DL packets due to the High BLER, L2TX Retransmission and L2RX Discards, the poor CINR Ratio, RoHC state mismatch between the UE 102 and the eNodeB, RoHC Decompression Error, Intra and inter-eNodeB HO failure, or the like, the UE 102 configures (202) the RTP/RTCP timeout reporting and threshold level. In an embodiment, the RTP/RTCP timer is used to monitor a downlink packet reception at the UE 102.The operation of the RTP/RTCP timeout reporting and threshold level includes the UE 102 configured to initiate the RTP/RTCP timer. Further, the UE 102 is configured to detect that the RTP/RTCP timer exceeds a RTP timeout threshold. In an embodiment, the RTP timeout threshold is defined by an IP Multimedia Subsystem (IMS) of the UE 102. In an embodiment, the RTP timeout threshold is defined by the network entity 104. In an embodiment, the network entity 104 is an eNodeB (eNB). The eNB may also be referred to as a base station, a base transceiver station, a radio base station, a radio transceiver, a transceiver function, a basic service set (BSS), an extended service set (ESS), or the like. In an embodiment, the network entity 104 is an IP Multimedia Subsystem server. In an embodiment, the network entity 104 is a Mobility Management Entity (MME).
[0051] The UE 102 sends (204) a message to the network entity 104 to trigger (206) a handover procedure before the RTP timer expires for continuing the call, where the message includes a remaining time period for the RTP/RTCP timer to get expired. In an embodiment, the message is a measurement report message. In an embodiment, the message is a Session Initiation Protocol (SIP) UPDATE message. In an embodiment, the message is a SIP INFO message. In an embodiment, the handover procedure is an intra LTE. In an embodiment, the handover procedure is a single radio voice call continuity (SRVCC) to 2G or 3G. The SRVCC provides an interim solution for handing over the VoLTE to 2G or 3G networks. The voice calls on the LTE network are meant to be packet switched calls which use IMS system to be made.
[0052] In an embodiment, the network entity transfers the call from a source cell to a target cell during the handover procedure. In an embodiment, the source cell is located within the LTE network, the LTE-A network, and the HSPA network. In an embodiment, the source cell is located in a network that can support packet switched (PS) data transmission for the call, including PS video data transmission and voice over Internet Protocol (VoIP) transmission and/or other PS technique for transmission of audio data for the voice or video call. However, the network of some embodiments can implement some other existing and/or future-developed cellular networking technology, such as various fifth generation (5G) and beyond cellular networking technologies, capable of supporting PS data transmission of both video and audio data for a voice or video call.
[0053] In an embodiment, the target cell is located within the LTE network, the LTE-Advanced (LTE-A) network, and the HSPA network. In an embodiment, the target cell is located within a legacy cellular network. The legacy cellular network may be any network having a circuit switched (CS) domain. The legacy cellular network can be, for example but not limited to, a third generation (3G) network, such as a Wideband Code Division Multiple Access (WCDMA), Universal Mobile Telecommunications System (UMTS) network, such as a Time Division Synchronous Code Division Multiple Access (TD-SCDMA) network. As a further example, the legacy cellular network can be a CDMA2000 network, such as a 1xRTT network, or other network standardized by the Third Generation Partnership Project 2 (3GPP2) that supports a CS domain. In another example, the legacy cellular network can be a second generation (2G) network such as a Global System for Mobile Communications (GSM) network. In an embodiment, the network entity 104 selects the target cell based on the message received from the source cell. The message for the target cell is configured based on the remaining time period to expire the RTP timer at the UE 102.
[0054] In an embodiment, if no measurement reports are available and the time does not permit, the network entity 104 may trigger blind HO.
[0055] In an example, the UE 102 is actively engaged in the VoLTE call within the source cell that is densely populated with the 4G LTE network. At a certain instance, the UE 102 may identify the packets lost due to the poor signaling condition. Based on the identified packets lost, the UE 102 initiates the RTP/RTCP timer. Further, the UE 102 detects the RTP/RTCP timer exceeds the RTP/RTCP timeout threshold. Based on the detection, the UE 102 sends the message to the network entity 104 to trigger the handover procedure before the RTP/RTCP timer expires for continuing the VoLTE call within the source cell or the nearby target cell.
[0056] In an example, the UE 102 is actively engaged in the VoLTE call within the source cell that is densely populated with the LTE-A network. At a certain instance, the UE 102 may identify the packets lost due to the High BLER. The network entity 104 reports the RTP/RTCP timeout threshold value (e.g., (0.75*RTP timeout) seconds) to the UE 102. The UE 102 configures the RTP/RTCP timeout reporting and threshold value (). If the UE 102 detects the RTP/RTCP timer value () exceeds the RTP/RTCP timeout threshold value () set by the network entity 104, the UE 102 sends the message along with the measure ID and report configuration to the network entity 104. After receiving the measurement report from the UE 102, the network entity 104 can identify the target cell for the handover (HO) procedure, and then collaborate with the target cell via an interface (e.g., X2 interface, or the like), to carry out the handover
[0057] In an example, the UE 102 is actively engaged in the VoLTE call within the source cell that is densely populated within the HSPA network. At a certain instance, the UE 102 may identify the packets lost due to the RoHC state mismatch between the UE 102 and the eNodeB. Based on the identified packets lost, the UE 102 initiates the RTP/RTCP timer. The UE 102 itself identifies the RTP/RTCP timer value crosses the threshold set by the network entity 104. If the RTP/RTCP timer crosses the RTP/RTCP timer threshold set by the network entity 104, the UE 102 sends the SIP UPDATE message to the network entity 104 and reports the current RTP/RTCP status/value in seconds to the network entity 104. Based on measurement reports, the network entity 104 can identify a target cell for the handover and then collaborate with the target cell via an interface (e.g., X2 interface, or the like), to carry out the handover.
[0058] The FIG. 2 shows the limited overview of a network environment for managing the call continuity at the UE 102, but it is to be understood that other embodiments are not limited thereto. Further, the FIG. 2 includes various other components interacting locally or remotely with the UE to manage the call continuity.
[0059] FIG. 3 illustrates various units of the UE 102, according to an embodiment as disclosed herein. In an embodiment, the UE 102 includes an IP Multimedia Subsystem (IMS) 302, a RTP/RTCP unit 304, a Radio Resource Control (RRC) unit 306, a communication unit 308, and a storage unit 310. The IMS 302 is configured to initiate the RTP/RTCP timer, when the call is active. The IMS 302 can be an IMS stack. The IMS 302 is configured to determine whether the current RTP timer value during the active IMS call exceeds the RTP timeout threshold. If the RTP timer exceeds the RTP/RTCP timeout threshold, the RRC unit 306 is configured to send the message to the network entity 104 to trigger the handover procedure before the RTP/RTCP timer expires for continuing the call.
[0060] The communication unit 308 is configured to send the handover procedure to the network entity 104. The communication unit 308 is configured for communicating internally between internal units and with external devices via one or more networks. The storage unit 310 may include one or more computer-readable storage media. The storage unit 310 may include non-volatile storage elements. Examples of such non-volatile storage elements may include magnetic hard disc, optical discs, floppy discs, flash memories, or forms of electrically programmable memories (EPROM) or electrically erasable and programmable (EEPROM) memories. In addition, the storage unit 310 may, in some examples, be considered a non-transitory storage medium. The term “non-transitory” may indicate that the storage medium is not embodied in a carrier wave or a propagated signal. However, the term “non-transitory” should not be interpreted that the storage unit 310 is non-movable. In some examples, the storage unit 310 can be configured to store larger amounts of information than a memory. In certain examples, a non-transitory storage medium may store data that can, over time, change (e.g., in Random Access Memory (RAM) or cache).
[0061] Although the FIG. 3 shows a limited number of units of the UE 102 but, it is to be understood that other embodiments are not limited thereon. In other embodiments, the UE 102 may include less or more number of units. Further, the labels or names of the units are used only for illustrative purpose and does not limit the scope of the invention. One or more units can be combined together to perform same or substantially similar function to manage the call continuity.
[0062] FIG. 4 illustrates various units of the network entity 104, according to an embodiment as disclosed herein. In an embodiment, network entity 104 includes a communication unit 402, a processor unit 404, a memory unit 406, and a storage unit 408. The processor unit 404 is coupled to the memory unit 408. The processor unit 304 is configured to receive the message when the call is active at the UE 102. The message comprises the remaining time period to expire the RTP/RTCP timer at the UE. Based on receiving the message, the processor unit 304 is configured to trigger the handover procedure before the RTP/RTCP timer expires for continuing the call at the UE 102. The processor unit 304 is configured to transfer the call from the source cell to the target cell during the handover procedure. The processor unit 304 is configured to select the target cell based on the message received from the source cell. The message for the target cell is configured based on the remaining time period to expire the RTP/RTCP timer at the UE 102.
[0063] The communication unit 402 is configured for communicating internally between internal units and with external devices via one or more networks. The storage unit 408 may include one or more computer-readable storage media. The storage unit 408 may include non-volatile storage elements. Examples of such non-volatile storage elements may include magnetic hard disc, optical discs, floppy discs, flash memories, or forms of electrically programmable memories (EPROM) or electrically erasable and programmable (EEPROM) memories. In addition, the storage unit 408 may, in some examples, be considered a non-transitory storage medium. The term “non-transitory” may indicate that the storage medium is not embodied in a carrier wave or a propagated signal. However, the term “non-transitory” should not be interpreted that the storage unit 408 is non-movable. In some examples, the storage unit 408 can be configured to store larger amounts of information than a memory. In certain examples, a non-transitory storage medium may store data that can, over time, change (e.g., in Random Access Memory (RAM) or cache).
[0064] Although the FIG. 4 shows a limited number of units of the network entity 104 but, it is to be understood that other embodiments are not limited thereon. In other embodiments, the network entity 104 may include less or more number of units. Further, the labels or names of the units are used only for illustrative purpose and does not limit the scope of the invention. One or more units can be combined together to perform same or substantially similar function to manage the call continuity.
[0065] FIG. 5 is a flow diagram illustrating a method 500 for managing the call continuity at the UE 102, according to an embodiment as disclosed herein. At step 502, the method 500 includes initiating the RTP/RTCP timer. In an embodiment, the method 500 allows the IMS 302 to initiate the RTP/RTCP timer. At step 504, the method 500 includes detecting the RTP/RTCP timer exceeds the timeout threshold. In an embodiment, the method 500 allows the IMS 302 to detect the RTP/RTCP timer exceeds the timeout threshold. In an embodiment, the timeout threshold is defined by the IMS 302 of the UE 102 or the network entity 104.At step 506, the method 500 includes sending the message to the network entity 104. In an embodiment, the method 500 allows the communication unit 308 to send the message to the network entity104. At step 408, the method 400 includes triggering the handover procedure. In an embodiment, the method 500 allows the network entity 104 to trigger the handover procedure. At step 410, the method 400 includes managing the call continuity. In an embodiment, the method 500 allows the network entity 104 to manage the call continuity.
[0066] The various actions, acts, blocks, steps, or the like in the method 500 may be performed in the order presented, in a different order or simultaneously. Further, in some embodiments, some of the actions, acts, blocks, steps, or the like may be omitted, added, modified, skipped, or the like without departing from the scope of the invention.
[0067] FIG. 6 is a sequence flow diagram illustrating the measurement report based handover scenario to manage the call continuity at the UE 102, according to an embodiment as disclosed herein. In an embodiment, the UE 102 is actively engaged in the VoLTE call. The eNB 104a reports (602) the RTP/RTCP timeout threshold in seconds to the RRC unit 306. The RRC unit 306 configures (604) the RTP/RTCP timeout reporting and threshold level in the IMS 302. The IMS 302 detects (606) the RTP/RTCP timer exceeds the RTP/RTCP timeout threshold set by the eNB 104a. If the RTP/RTCP timer exceeds the RTP/RTCP timeout threshold set by the eNB104a, the IMS 302 sends (608) the message along with the measure identification (ID) and report configuration to the RRC unit 306. The RRC unit 306 sends the measurement report with the RTP status to the eNB 104a. Based on measurement reports, the network entity 104 initiates the HO preparation. In an embodiment, the HO can be an intra LTE. In an embodiment, the HO can be the SRVCC to 2G or 3G.
[0068] In an embodiment, if no measurement reports are available and the time permits, the network entity 104 can configure measurements and HO thereafter. In an embodiment, if no measurement reports are available and time does not permit, the network entity 104 may trigger the blind HO.
[0069] In an example, the UE 102 is actively engaged in the VoLTE call within the source cell that is densely populated with the 4G LTE network. The eNB 104a reports the RTP/RTCP timeout threshold up to 15 seconds to the RRC unit 310. The RRC unit 310 configures the RTP/RTCP timeout reporting and threshold level up to 10 seconds in the IMS 302. The IMS 302 detects the RTP/RTCP timer value (10 seconds) exceeds the RTP/RTCP timeout threshold value (15 seconds) set by the eNB 104a. If the RTP/RTCP timer exceeds the RTP/RTCP timeout threshold set by the eNB 104a, the IMS 302 RRC sends the message along with the measure ID and report configuration to the RRC unit 306. The RRC unit 306 sends the measurement report with the RTP status to the eNB 104a. Based on measurement reports, the network entity 104 initiates the HO preparation.
[0070] FIG. 7 is a sequence flow diagram illustrating the SIP UPDATE message based handover scenario to manage the call continuity at the UE 102, according to an embodiment as disclosed herein. In an embodiment, the UE 102 is actively engaged in the VoLTE call. At a certain instance, the UE 102 may identify the packets lost due to the poor signaling condition. Based on the identified packets lost, the UE 102 initiates the RTP/RTCP timer. The IMS 302 itself identifies (702) the RTP/RTCP timer crosses the threshold set by the IMS 302. If the RTP/RTCP timer crosses the RTP/RTCP timer threshold set by the IMS 302, the IMS 302 sends (704) the SIP UPDATE Message to the IMS 104c in the network and reports the RTP/RTCP status/value in seconds to the IMS 104c in the network. The IMS 104c triggers (706) the HO to a SCC AS. The SCC AS refers to the IMS entity corresponding to Service Centralization and Continuity, Application Server. The SCC AS triggers the HO to the MME. The MME triggers the HO to the eNB 104a. Based on measurement reports, the network entity 104 initiates the HO preparation. In an embodiment, the HO can be an intra LTE. In an embodiment, the HO can be the SRVCC to 2G or 3G.
[0071] In an embodiment, if no measurement reports are available and the time permits, the network entity 104 may configure measurements and HO thereafter. In an embodiment, if no measurement reports are available and the time does not permit, the network entity 104 may trigger the blind HO.
[0072] In an example, the UE 102 is actively engaged in the VoLTE call within the source cell that is densely populated with 4G LTE-A network. At a certain instance, the UE 102 may identify the packets lost due to the poor signaling condition. Based on the identified packets lost, the UE 102 initiates the RTP/RTCP timer. The IMS 302 itself identifies the RTP/RTCP timer value (15 seconds) crosses the threshold (10 seconds) set by the IMS 302. If the RTP/RTCP timer crosses the RTP/RTCP timer threshold set by the IMS 302, the IMS 302 sends the SIP UPDATE Message to the IMS 104c in the network and reports the RTP/RTCP status/value in seconds (10 seconds) to the IMS 104c in the network. Based on measurement reports, the network entity 104 initiates the HO preparation.
[0073] FIG. 8 is a sequence flow diagram illustrating the SIP INFO message based handover scenario to manage the call continuity at the UE 102, according to an embodiment as disclosed herein. In an embodiment, the UE 102 is actively engaged in the VoLTE call. At a certain instance, the UE 102 may identify the packets lost due to the poor signaling condition. Based on the identified packets lost, the UE 102 initiates the RTP/RTCP timer. The IMS 302 itself identifies (802) the RTP/RTCP timer crosses the threshold set by the IMS 302. If the RTP/RTCP timer crosses the RTP/RTCP timer threshold set by the IMS 302, the IMS 302 sends (804) the SIP INFO Message to the IMS 104c in the network and reports the RTP/RTCP status/value in seconds to the IMS 104c in the network. The IMS 104c triggers (706) the HO to the SCC AS. The SCC AS refers to the IMS entity corresponding to Service Centralization and Continuity, Application Server. The SCC AS triggers the HO to the MME 104b. The MME 104b triggers the HO to the eNB 104a. Based on measurement reports, the network entity 104 initiates the HO preparation. In an embodiment, the HO can be an intra LTE. In an embodiment, the HO can be the SRVCC to 2G or 3G.
[0074] In an embodiment, if no measurement reports are available and the time permits, the network entity 104 can configure measurements and HO thereafter. In an embodiment, if no measurement reports are available and the time does not permit, the network entity 104 can trigger the blind HO.
[0075] In an example, the UE 102 is actively engaged in the VoLTE call within the source cell that is densely populated with 4G LTE. At a certain instance, the UE 102 may identify the packets lost due to the poor signaling condition. Based on the identified packets lost, the UE 102 initiates the RTP/RTCP timer. The IMS 302 itself identifies the RTP/RTCP timer value crosses the threshold (set by the IMS 302. If the RTP/RTCP timer crosses the RTP/RTCP timer threshold set by the IMS 302, the IMS 302 sends) the SIP INFO message to the IMS 104c in the network and reports the current RTP/RTCP status/value in seconds to the IMS 104c in the network. Based on measurement reports, the network entity 104 initiates the HO preparation.
[0076] FIG. 9 is a sequence flow diagram illustrating network side operations to perform the handover to manage the call continuity at the UE 102, according to an embodiment as disclosed herein. The UE 102 sends (902) the SIP UPDATE or the SIP UPDATE INFO message with the RTP/RTCP timeout to the IMS 104c. The IMS 104c indicates (904) the RTP/RTCP Timeout value to a Voice Call Continuity Application server (VCC AS) 104d to start the HO procedure. In an embodiment, the VCC AS 104d updates (906) the HO Procedure to the MME 104b to configure B2 Measurements for IRAT HO. In an embodiment, the VCC AS104dconfigures (906) a new VoLTE specific measurement ID. The MME 104a configures (908) B2 Events from the UE 102.
[0077] In an embodiment, the UE 102 validates (910) the measurements reports and starts the HO procedure to the eNB 104a. The eNB 104a starts (912) the HO Procedure and performs the call conversion from the IMS to the CS call.
[0078] In an embodiment, the UE 102 triggers (914) the HO for the SRVCC. The UE 102 continues (916) the CS Call over 2G/3G.
[0079] FIG. 10 illustrates a computing environment 1002 implementing a mechanism for managing the call continuity at the UE 102, according to an embodiment as disclosed herein. As depicted in the figure, the computing environment 1002 comprises at least one processing unit 1008 that is equipped with a control unit 1004, an Arithmetic Logic Unit (ALU) 1006, a memory 1010, a storage unit 1012, a plurality of networking devices 1016 and a plurality Input output (I/O) devices 1014. The processing unit 1008 is responsible for processing the instructions of the technique. The processing unit 1008 receives commands from the control unit 1004 in order to perform its processing. Further, any logical and arithmetic operations involved in the execution of the instructions are computed with the help of the ALU 1006.
[0080] The overall computing environment 1002 can be composed of multiple homogeneous or heterogeneous cores, multiple CPUs of different kinds, special media and other accelerators. The processing unit 1008 is responsible for processing the instructions of the technique. Further, the plurality of processing units 1204 may be located on a single chip or over multiple chips.
[0081] The technique comprising of instructions and codes required for the implementation are stored in either the memory unit 1010 or the storage 1012 or both. At the time of execution, the instructions may be fetched from the corresponding memory 1010 or storage 1012, and executed by the processing unit 1008.
[0082] In case of any hardware implementations various networking devices 1016 or external I/O devices 1014 may be connected to the computing environment 1002 to support the implementation through the networking unit and the I/O device unit.
[0083] The embodiments disclosed herein can be implemented through at least one software program running on at least one hardware device and performing network management functions to control the elements. The elements shown in the FIGS. 2 to 10 include blocks, elements, actions, acts, steps, or the like which can be at least one of a hardware device, or a combination of hardware device and software module.
[0084] The foregoing description of the specific embodiments will so fully reveal the general nature of the embodiments herein that others can, by applying current knowledge, readily modify and or adapt for various applications such specific embodiments without departing from the generic concept, and, therefore, such adaptations and modifications should and are intended to be comprehended within the meaning and range of equivalents of the disclosed embodiments. It is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation. Therefore, while the embodiments herein have been described in terms of preferred embodiments, those skilled in the art will recognize that the embodiments herein can be practiced with modification within the spirit and scope of the embodiments as described herein.