Ue with multiple subscriber identity modules with improved pause / resume operation

Abstract

The present disclosure relates to a UE having a plurality of subscriber identity modules with improved pause / resume operations. The present disclosure provides devices and related methods for operating a dual subscriber identity module (SIM) dual standby (DSDS) user equipment (UE) configured with a first SIM and a second SIM. The UE performs communications with a first cellular network using a first SIM and a first radio resource control (RRC) connection, and receives a request to perform higher priority communications using a second SIM. In response to a request to perform the higher priority communication, the UE transmits a request to the first network to suspend the first RRC connection. After transmitting a request to suspend the first RRC connection, the UE receives a message from the first network to place the first RRC connection in an inactive state and starts a timer for determining whether the first RRC connection remains in the inactive state or transitions to an idle state.

Description

[0001] This application is a divisional application of an invention patent application with an application date of July 10, 2019, application number 201910618956.0, and titled “UE WITH MULTIPLE USER IDENTITY MODULES WITH IMPROVED PAUSE / RESUME OPERATIONS”. Technical Field

[0002] The present disclosure relates to the field of wireless communications, and more particularly to a user equipment (UE) having multiple subscriber identity modules that performs improved network notification during SIM suspend / resume operations. Background Art

[0003] The use of wireless communication systems is growing rapidly. In addition, wireless communication technology has evolved from voice communications only to also include the transmission of data (such as the Internet and multimedia content). In order to enable a wireless device to access a wireless communication network (e.g., a cellular telecommunications network) according to at least some wireless communication technologies and standards, a user may subscribe to a service provider ("operator"), which in turn may provide such services to the user, for example, via the wireless communication network they operate. Such users in a wireless communication network are typically assigned user identity information, which may be stored in the user's wireless device, for example, as part of a subscriber identity module (SIM). For example, many wireless devices may be provided with a slot for a removable subscriber identity module (SIM) card. Providing such a slot may enable a user to select and / or change their user identity independently of the wireless device, as the user may switch from their current SIM card to a different SIM card at any given time as needed. Recently, UE devices may be equipped with an electronic SIM (eSIM), in which an embedded memory in the UE stores the user's user identity information.

[0004] Many UE devices are now designed as dual SIM or multi-SIM phones, where the UE is able to store two or more sets of user identity information for a user. This enables the UE to, for example, store a first user identity information for a user's home phone number, and also store a second user identity information for a user's business phone number. Alternatively or in addition, one of the SIMs may be used primarily for voice calls, while the other may be used primarily for data transmission. Dual SIM or multi-SIM UE devices are particularly popular in recent developing economies such as China.

[0005] One type of dual SIM UE is called Dual Subscriber Identity Dual Active (DSDA) and may include multiple receiver (Rx) architectures. A DSDA UE is able to use two SIMs and two radio components to simultaneously maintain two sets of active data communications, e.g., the UE may use one SIM to make a voice call while performing data communications (e.g., Internet browsing) on ​​the second SIM.

[0006] Another type of dual SIM UE may have only a single Rx architecture (e.g., to save cost and reduce size requirements), and may be referred to as dual subscriber identity module dual standby (DSDS). In a UE that includes only a single receiver, only one SIM may be active at any given time. Thus, when the UE is making a voice call using the first SIM, the second SIM will be idle. In some cases, when a SIM is currently in use and the UE detects the initiation of a higher priority activity that requires the other SIM, the UE may suspend the activity on the first SIM in order to conduct the higher priority activity on the other SIM. In a UE with multiple SIM devices and only one radio, the UE may encounter network problems when the SIM suspends and then resumes the radio resource control (RRC) connection with the network.

[0007] Therefore, improvements in wireless communications, particularly with respect to multiple user identity functionality, would be desirable. Summary of the invention

[0008] In view of the above and other considerations, it is desirable to extend the functionality of wireless devices with respect to user identity. In particular, it is desirable to provide improved state synchronization between wireless devices and networks in an energy-efficient manner. The present disclosure relates to such techniques for facilitating state synchronization according to various embodiments.

[0009] Therefore, embodiments of the present disclosure may relate to a method for state synchronization in a dual user identity module dual standby (DSDS) UE device, to a UE device configured to implement such a method, and / or to a non-transient computer-accessible memory medium storing program instructions that can be executed by a processor to implement such a method. The UE device may include a radio component for performing wireless communication (e.g., including one or more antennas and / or other radio components). The UE device may also include a processing element that is configured to implement part or all of the method (e.g., by executing program instructions). The UE device may also include one or more user interface elements, such as a display. In addition, the UE device may include a non-transient computer-accessible memory medium that can store program instructions that can be executed by the UE.

[0010] In some embodiments, the DSDS UE is configured to have a first SIM and a second SIM. The UE performs communications with a first cellular network using the first SIM and a first radio resource control (RRC) connection, and receives a request to perform higher priority communications using the second SIM. In response to the request to perform higher priority communications, the UE transmits a request to the first network to suspend the first RRC connection. After transmitting the request to suspend the first RRC connection, the UE receives a message from the first network to place the first RRC connection in an inactive state, and starts a timer, wherein the timer is used to determine whether the first RRC connection remains in the inactive state or transitions to an idle state. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] A better understanding of the presently disclosed subject matter may be obtained when the following detailed description of the preferred embodiments is considered in conjunction with the following drawings, in which:

[0012] Figure 1 to Figure 2 An exemplary wireless communication system between a UE device and one or more networks through one or more base stations according to some embodiments is shown;

[0013] Figure 3 An exemplary cellular network system including an evolved packet core (EPC) according to some embodiments is shown;

[0014] Figure 4 An exemplary block diagram of a user equipment device is shown;

[0015] Figure 5 An exemplary block diagram of a base station is shown;

[0016] Figure 6 A message sequence chart illustrating an exemplary method according to some embodiments, wherein the UE provides information to the network regarding a suspend / resume operation to maintain RRC state synchronization, wherein the resumption occurs without a timeout event;

[0017] Figure 7 A message sequence chart illustrating an exemplary method according to some embodiments, wherein the UE provides information to the network regarding a suspend / resume operation to maintain RRC state synchronization, wherein the resumption is performed in the event of a timeout;

[0018] Figure 8 A message sequence chart illustrating an exemplary method according to some embodiments, wherein the UE provides information about the suspend / resume operation to the network, and the network stores state information of the connection to maintain RRC state synchronization;

[0019] Fig. 9 A message sequence chart illustrating the problem caused by RRC state mismatch;

[0020] Fig.10 A message sequence chart illustrating an exemplary method according to some embodiments, wherein a pause timer is utilized to avoid RRC state mismatch;

[0021] Fig.11 A message sequence chart illustrating an exemplary method according to some embodiments in which network coordination is utilized to avoid RRC state mismatches; and

[0022] Fig.12 Message sequence chart illustrating an exemplary method according to some embodiments, in which the UE notifies the network of connection release to avoid RRC state mismatch.

[0023] Although the features described herein are susceptible to various modifications and alternative forms, specific embodiments thereof are shown by way of example in the drawings and are described in detail herein. However, it should be understood that the drawings and detailed description thereof are not intended to limit this document to the specific forms disclosed, but on the contrary, the purpose is to cover all modifications, equivalents and alternatives that fall within the spirit and scope of the subject matter as defined by the appended claims. DETAILED DESCRIPTION

[0024] Acronyms

[0025] The following acronyms are used in this disclosure:

[0026] 3GPP: Third Generation Partnership Project

[0027] 3GPP2: Third Generation Partnership Project 2

[0028] GSM: Global System for Mobile Communications

[0029] UMTS: Universal Mobile Telecommunications System

[0030] LTE: Long Term Evolution

[0031] LTE-A: LTE Advanced

[0032] SIM: Subscriber Identity Module

[0033] eSIM: embedded SIM

[0034] IMSI: International Mobile Subscriber Identity

[0035] MCC: Mobile Country Code

[0036] MNC: Mobile Network Code

[0037] the term

[0038] The following is a glossary of terms used in this disclosure:

[0039] Memory medium - any of various types of memory devices or storage devices. The term "memory medium" is intended to include installation media, such as CD-ROM, floppy disk or tape devices; computer system memory or random access memory such as DRAM, DDR RAM, SRAM, EDO RAM, Rambus RAM, etc.; non-volatile memory such as flash memory, magnetic media, for example, hard disk drive or optical storage device; registers, or other similar types of memory elements, etc. The memory medium may also include other types of memory, or a combination thereof. In addition, the memory medium may be located in a first computer system executing a program, or may be located in a different second computer system connected to the first computer system via a network such as the Internet. In the latter case, the second computer system may provide program instructions to the first computer for execution. The term "memory medium" may include two or more memory media that may reside in different locations in different computer systems connected, for example, via a network. The memory medium may store program instructions (e.g., expressed as a computer program) that may be executed by one or more processors.

[0040] Carrier Medium—storage media as described above, and physical transmission media such as a bus, network, and / or other physical transmission media that transport signals such as electrical, electromagnetic or digital signals.

[0041] Programmable hardware element - includes various hardware devices that include multiple programmable function blocks connected via programmable interconnects. Examples include FPGA (field programmable gate array), PLD (programmable logic device), FPOA (field programmable object array), and CPLD (complex PLD). Programmable function blocks can vary from fine-grained (combinational logic unit or lookup table) to coarse-grained (arithmetic logic unit or processor core). Programmable hardware elements may also be referred to as "configurable logic units".

[0042] Computer System—Any of various types of computing or processing systems, including a personal computer system (PC), a mainframe computer system, a workstation, a network appliance, an Internet appliance, a personal digital assistant (PDA), a personal communication device, a smart phone, a television system, a grid computing system, or other devices or combinations of devices. In general, the term "computer system" may be broadly defined to encompass any device (or combination of devices) having at least one processor that executes instructions from a memory medium.

[0043] User Equipment (UE) (or "UE device") - any of various types of computer system devices that are mobile or portable and perform wireless communications. Examples of UE devices include mobile phones or smart phones (such as iPhone TM , based on AndroidTM phones), wearable devices (e.g., smart watches, smart glasses), portable gaming devices (e.g., Nintendo DS TM , PlayStation Portable TM 、Gameboy Advance TM , iPhone TM ), laptops, PDAs, portable Internet devices, music players, data storage devices or other handheld devices, etc. In general, the term "UE" or "UE device" can be broadly defined to include any electronic, computing and / or telecommunication device (or combination of devices) that is convenient for a user to transport and capable of wireless communication.

[0044] Base Station—The term “base station” has the full breadth of its ordinary meaning and includes at least a wireless communication station that is installed at a fixed location and used to communicate as part of a wireless telephone system or radio system.

[0045] Processing Element - refers to various elements or combinations of elements. Processing elements include, for example, circuits such as ASICs (application specific integrated circuits), portions or circuits of individual processor cores, entire processor cores, individual processors, programmable hardware devices such as field programmable gate arrays (FPGAs), and / or larger portions of systems including multiple processors.

[0046] Automatic—refers to an action or operation performed by a computer system (e.g., software executed by a computer system) or a device (e.g., a circuit, a programmable hardware element, an ASIC, etc.) without the need for user input to directly specify or perform the action or operation. Thus, the term "automatic" is in contrast to a user manually performing or specifying an action, where the user provides input to directly perform the action. An automatic process may be initiated by input provided by a user, but subsequent actions performed "automatically" are not specified by the user, i.e., are not performed "manually," where the user specifies each action to be performed. For example, a user filling out an electronic form by selecting each field and providing input specifying information (e.g., by typing in information, selecting check boxes, radio selections, etc.) is manually filling out the form, even though the computer system must update the form in response to the user action. The form may be automatically filled out by a computer system, where the computer system (e.g., software executed on the computer system) analyzes the fields of the form and fills out the form without any user input specifying the answers to the fields. As indicated above, a user may invoke automatic filling out of a form, but not participate in the actual filling out of the form (e.g., the user does not manually specify the answers to the fields but rather they are automatically completed). This specification provides various examples of operations that are automatically performed in response to actions taken by a user.

[0047] Figures 1 to 3 -Communication system

[0048] Figure 1 and Figure 2 An exemplary (and simplified) wireless communication system is shown. Note that Figure 1 and Figure 2 The systems are merely examples of some possible systems, and embodiments may be implemented in any of a variety of systems as desired.

[0049] Figure 1 An exemplary wireless communication system of includes a base station 102A that communicates with one or more user equipment (UE) devices 106A, 106B, etc., through 106N via a transmission medium. Each of the user equipment devices may be referred to herein as a "user equipment" (UE). Figure 2 In an exemplary wireless communication system of , in addition to base station 102A, base station 102B also communicates (eg, simultaneously or concurrently) with UE devices 106A, 106B, etc., through 106N via a transmission medium.

[0050] Base stations 102A and 102B may be base transceiver stations (BTS) or cell sites, and may include hardware to enable wireless communications with user devices 106A through 106N. Each base station 102 may also be equipped to communicate with a core network 100 (base station 102A may be coupled to core network 100A, and base station 102B may be coupled to core network 100B), which may be a core network of a cellular service provider. Each core network 100 may also be coupled to one or more external networks (such as external network 108), which may include the Internet, a public switched telephone network (PSTN), or any other network. Thus, base station 102A may facilitate communications between user devices and / or between user devices and network 100A; Figure 2 In the exemplary system of FIG. 1 , base station 102B may also facilitate communications between user devices and / or between user devices and network 100B.

[0051] The base stations 102A and 102B and the user equipment may be configured to communicate via a transmission medium using any of a variety of radio access technologies (RATs), also referred to as wireless communication technologies or telecommunication standards, such as GSM, UMTS (WCDMA), LTE, Advanced LTE (LTE-A), 3GPP2 CDMA2000 (e.g., 1xRTT, 1xEV-DO, HRPD, eHRPD), Wi-Fi, WiMAX, etc.

[0052] For example, base station 102A and core network 100A may operate according to a first cellular communication standard (e.g., LTE), while base station 102B and core network 100B may operate according to a second (e.g., different) cellular communication standard (e.g., GSM, UMTS, and / or one or more CDMA2000 cellular communication standards). The two networks may be controlled by the same network operator (e.g., cellular service provider or "operator") or different network operators. In addition, the two networks may operate independently of each other (e.g., if they operate according to different cellular communication standards), or may operate in a somewhat coupled or tightly coupled manner.

[0053] It should also be noted that although Figure 2 The exemplary network configuration shown may use two different networks to support two different cellular communication technologies, but other network configurations implementing multiple cellular communication technologies are also possible. As an example, base stations 102A and 102B may operate according to different cellular communication standards, but are coupled to the same core network. As another example, a multi-mode base station capable of simultaneously supporting different cellular communication technologies (e.g., LTE and CDMA 1xRTT, GSM and UMTS, or any other combination of cellular communication technologies) may be coupled to a core network that also supports different cellular communication technologies. Any other various network deployment scenarios are also possible.

[0054] As another possibility, base station 102A and base station 102B may also operate according to the same wireless communication technology (or a set of overlapping wireless communication technologies). For example, base station 102A and core network 100A may be operated by one cellular service provider independently of base station 102B and core network 100B, and base station 102B and core network 100B may be operated by different (e.g., competing) cellular service providers. Thus, in this case, despite using similar and possibly compatible cellular communication technologies, UE devices 106A-106N may communicate independently with base stations 102A-102B, perhaps by utilizing separate subscriber identities to communicate with different operator networks.

[0055] UE 106 can communicate using multiple wireless communication standards. For example, UE 106 can be configured to communicate using any one or two cellular communication standards in a 3GPP cellular communication standard (such as LTE) and / or a 3GPP2 cellular communication standard (such as a cellular communication standard in the CDMA2000 series of cellular communication standards). As another example, UE 106 can be configured to communicate using different 3GPP cellular communication standards (such as two or more of GSM, UMTS, LTE, or LTE-A). Therefore, as described above, UE 106 can be configured to communicate with base station 102A (and / or other base stations) according to a first cellular communication standard (e.g., LTE) and can also be configured to communicate with base station 102B (and / or other base stations) according to a second cellular communication standard (e.g., one or more CDMA2000 cellular communication standards UMTS, GSM, etc.).

[0056] Base stations 102A and 102B and other base stations operating according to the same or different cellular communication standards may thus be provided as one or more cell networks that can provide continuous or nearly continuous overlapping service to UEs 106A-106N and similar devices over a wide geographic area via one or more cellular communication standards.

[0057] The UE 106 may also or alternatively be configured to communicate using WLAN, Bluetooth, one or more global navigation satellite systems (GNSS, such as GPS or GLONASS), one and / or more mobile television broadcast standards (e.g., ATSC-M / H or DVB-H), etc. Other combinations of wireless communication standards (including more than two wireless communication standards) are also possible.

[0058] UE 106 may be a device with wireless network connectivity, such as a mobile phone, handheld device, computer or tablet, or substantially any type of wireless device.

[0059] The UE may include a processor configured to execute program instructions stored in a memory. The UE may perform any of the method implementations described herein by executing such stored instructions. Alternatively or in addition, the UE may include a programmable hardware element such as an FPGA (field programmable gate array) configured to perform any of the method implementations described herein, or any part of any of the method implementations described herein.

[0060] UE 106 may be configured to communicate using any of a number of wireless communication protocols. For example, UE 106 may be configured to communicate using two or more of GSM, UMTS (W-DCMA, TD-SCDMA, etc.), CDMA2000 (1xRTT, 1xEV-DO, HRPD, eHRPD, etc.), LTE, LTE-A, WLAN, or GNSS. Other combinations of wireless communication standards are also possible.

[0061] UE 106 may include one or more antennas for communicating using one or more wireless communication protocols. UE 106 may share one or more portions of a receive chain and / or a transmit chain between multiple wireless communication standards; for example, UE 106 may be configured to communicate using a single shared radio using one (or both) of GSM or LTE. The shared radio may include a single antenna, or may include multiple antennas for performing wireless communication (e.g., for MIMO).

[0062] Figure 3 —Example Cellular Network

[0063] Figure 3 A simplified block diagram of an exemplary cellular network (wireless communication system) is shown, which is particularly useful for implementing the various embodiments described herein. UE 106 can communicate with a cellular network, wherein the cellular network may include a base station 102 (or eNodeB) and an evolved packet core (EPC) 101, as shown. UE 106 can communicate with base station 102 in a wireless manner. Base station 102 can be coupled to a core network, which is shown as an evolved packet core (EPC) 101 in this exemplary embodiment. As shown, EPC 101 may include a mobility management entity (MME) 322, a home subscriber server (HSS) 324, and a serving gateway (SGW) 326. EPC 100 may also include various other devices well known to those skilled in the art.

[0064] The operations described herein as being performed by a cellular network (or NW) may be performed by Figure 3 The cellular network operations may be performed by one or more of the cellular network devices shown, such as one or more of the base station 102, the MME 322, the HSS 324 or the SGW 326 in the EPC 100, and possibly other devices.

[0065] Figure 4 -Exemplary block diagram of UE

[0066] Figure 4An exemplary block diagram of UE 106 is shown. As shown, UE 106 may include a system on chip (SOC) 300, which may include parts for various purposes. For example, as shown, SOC 300 may include one or more processors 302 that can execute program instructions for UE 106, and display circuit 304 that can perform graphics processing and provide display signals to display 345. One or more processors 302 may also be coupled to a memory management unit (MMU) 340, which may be configured to receive addresses from one or more processors 302 and convert those addresses into locations in memory (e.g., memory 306, read-only memory (ROM) 350, NAND flash memory 310) and / or other circuits or devices, such as display circuit 304, radio component 330, connector I / F 320 and / or display 345. MMU 340 may be configured to perform memory protection and page table conversion or setup. In some embodiments, MMU 340 may be included as part of one or more processors 302.

[0067] As shown, SOC 300 may be coupled to various other circuits of UE 106. For example, UE 106 may include various types of memory (e.g., including flash memory 310), a connector interface 320 (e.g., for coupling to a computer system, a docking station, a charging station, etc.), a display 345, and wireless communication circuitry 330 (e.g., for GSM, UMTS, LTE, LTE-A, CDMA2000, Bluetooth, Wi-Fi, GPS, etc.).

[0068] The UE device 106 may include at least one antenna, and may include multiple antennas, for performing wireless communications with a base station and / or other devices. For example, the UE device 106 may use antenna 335 to perform wireless communications. As described above, the UE may be configured to communicate wirelessly using multiple wireless communication standards.

[0069] The UE 106 may also include one or more user interface elements. The user interface elements may include various elements such as a display 345 (which may be a touch screen display), a keyboard (which may be a separate keyboard or may be implemented as part of the touch screen display), a mouse, a microphone and / or a speaker, one or more cameras, a slider, and / or a dial, one or more buttons, and / or any of a variety of other elements capable of providing information to a user and / or receiving or interpreting user input.

[0070] As shown, UE 106 may also include two or more subscriber identity modules (SIMs) 360 and 362. One or both of SIMs 360 and 362 may be implemented as embedded SIMs (eSIMs). In this case, SIMs 360 and / or 362 may be implemented in device hardware and / or software. For example, in some embodiments, UE 106 may include an embedded UICC (eUICC), for example, a device that is built into UE 106 and is not removable. The eUICC may be programmable so that one or more eSIMs may be implemented on the eUICC. In other embodiments, the eSIM may be installed in UE 106 software, for example, as program instructions stored on a storage medium (such as memory 306 or flash memory 310) executed on a processor (such as processor 302) in UE 106. As an example, SIM 360 may be an application executed on a universal integrated circuit card (UICC). Alternatively or in addition, one or both of SIMs 360 and 362 may be implemented as a removable SIM card.

[0071] Each SIM 360 or 362 may include multiple types of information, including personalized information specific to a user and / or device (e.g., personalized information), and information not specific to a user and / or device (e.g., public information). The personalized information may include user / unit specific data, such as information identifying the user / unit to its operator's network, personalized authorization and / or security information, etc. Some or all of this personalized information may be used as a user identity for UE 106, for example, to identify UE 106 to an operator's network and obtain cellular service from the operator.

[0072] As an example, the personalized information may include one or more International Mobile Subscriber Identity (IMSI) codes. An IMSI may identify a user to its operator's network. An IMSI may, for example, be a number including the user's "home" Mobile Country Code (MCC) and Mobile Network Code (MNC), as well as a Mobile Subscription Identification Number (MSIN) unique to the user. The personalized information may also or alternatively include a Personal Identification Number (PIN) (e.g., a code that a user may use to access their SIM), a Personal Unlock Code and / or Personal Unlock Key (PUC / PUK), and one or more Authentication Keys (K / Ki). Any of a variety of other personalized information may also or alternatively be used as desired.

[0073] Thus, each SIM 360 and 362 may contain subscriber identity information that may be used to identify the UE 106 to its user's carrier cellular network. As described above, the UE 106 may utilize multiple subscriber identities. For example, a user may desirably obtain service from multiple carriers for any of a variety of reasons, including different coverage / service areas of different carriers, different service plans / pricing offered by different carriers, or different technologies used. In some cases, it may be desirable to utilize multiple subscriber identities (whether from the same or different carriers) as a means of distinguishing between types of interactions, such as work-related communications and personal communications.

[0074] As another possibility, situations may arise where it may be desirable for some operators implementing LTE networks to utilize multiple user identities in a single device. Specifically, in many cases, LTE (e.g., as a packet-switched communication technology) networks may be (at least initially) deployed for data communications (e.g., web browsing, email and other networking applications, etc.), while (e.g., pre-existing) GSM and / or UMTS (e.g., which may include circuit-switched communication technologies) networks may be utilized for voice communications.

[0075] As further described below, the UE may implement various techniques that enable a particular SIM to perform suspend and resume operations with a cellular network while reducing disruptions due to RRC state mismatches. Thus, as further described later herein, the UE 106 may include hardware and software components for implementing methods for improving suspend / resume operations when switching between using different SIMs.

[0076] The processor 302 of the UE device 106 may be configured to implement some or all of the methods described herein, for example, by executing program instructions stored on a memory medium (e.g., a non-transitory computer-readable memory medium). In other embodiments, the processor 302 may be configured as a programmable hardware element such as an FPGA (field programmable gate array), or as an ASIC (application-specific integrated circuit).

[0077] Figure 5 - Exemplary block diagram of a base station

[0078] Figure 5 An exemplary block diagram of a base station 102 is shown. Note that Figure 5The base station of is only one example of a possible base station. As shown, the base station 102 may include one or more processors 404 that may execute program instructions for the base station 102. The one or more processors 404 may also be coupled to a memory management unit (MMU) 440 (which may be configured to receive addresses from the one or more processors 102 and translate these addresses into locations in memory (e.g., memory 460 and read-only memory (ROM) 450)) or other circuits or devices.

[0079] Base station 102 may include at least one network port 470. Network port 470 may be configured to couple to a telephone network and provide access to the telephone network described above. Figure 1 and Figure 2 Multiple devices of the telephone network described in, such as UE device 106.

[0080] The network port 470 (or an additional network port) may also or alternatively be configured to couple to a cellular network, such as a core network of a cellular service provider. The core network may provide mobility-related services and / or other services to multiple devices, such as the UE device 106. In some cases, the network port 470 may be coupled to a telephone network via the core network, and / or the core network may provide a telephone network (e.g., in other UE devices served by the cellular service provider).

[0081] The base station 102 may include at least one antenna 434 and possibly multiple antennas. The at least one antenna 434 may be configured to function as a wireless transceiver and may be further configured to communicate with the UE device 106 via the radio component 430. The antenna 434 communicates with the radio component 430 via a communication chain 432. The communication chain 432 may be a receive chain, a transmit chain, or both. The radio component 430 may be configured to communicate via various radio communication standards, including but not limited to LTE, WCDMA, CDMA2000, etc.

[0082] The processor 404 of the base station 102 may be configured to implement part or all of the methods described herein, for example, by executing program instructions stored on a memory medium (e.g., a non-transitory computer-readable memory medium). Alternatively, the processor 404 may be configured as a programmable hardware element such as an FPGA (field programmable gate array) or as an ASIC (application-specific integrated circuit) or a combination thereof.

[0083] like Figure 3 The cellular network device shown may have a somewhat similar architecture to that described above, but typically does not include RF circuitry or antennas. Figure 3 Each of the cellular network devices shown will typically have a processing element and memory for performing its respective functions.

[0084] As used herein, a network or cellular network (e.g., NW1 and / or NW2 as described below) may refer to one or more physical entities included in the network infrastructure to perform the method. Figure 5 The gNB (or eNB) shown may receive indications and messages directly from the UE, and may relay these messages from the UE to the Access and Mobility Management Function (AMF) or Mobility Management Entity (MME) on the core network side. The MME (or AMF) may notify the gNB (or eNB) to retain the UE's RRC context (i.e., connection state and / or established EPS bearers / PDU sessions and QoS details), the MME (or AMF) may start a timer, and if the timer expires before the suspended SIM is resumed, the MME (or AMF) may notify the Serving Gateway (S-GW) or User Plane Function (UPF) to release the UE's bearer / PDN context, and notify the eNB (or gNB) to release the UE context (i.e., forget the C-RNTI and the rest of the UE's state information and consider the UE to be idle). If the timer is running and the eNB (or gNB) obtains an RRC resume request from the UE, the eNB (or gNB) may confirm that the C-RNTI exists and the UE context may be restored and may forward the resume request to the MME (or AMF), which may notify the S-GW (or UPF) to modify the radio bearers (e.g., if they have previously told the S-GW or UPF to freeze its context), stop the timer, and / or continue as if the UE was connected. In other words, the combination of eNB-MME-SGW for LTE or gNB-AMF-UPF for 5G NR may be understood to be interconnected to perform the embodiments described herein.

[0085] RRC State Mismatch Avoidance – Problem Statement

[0086] As mentioned above, some UE devices may be able to contain multiple subscriber identity modules or SIMs. In some cases, these SIMs may be universal SIMs or USIMs.

[0087] Some UE devices with multiple SIMs, i.e. dual SIM and multi-SIM devices, including multi-USIM (or MUSIM) devices, may have a single receiver (RX) architecture. In other words, some multi-SIM UEs may each have only one receiver system for cellular communications for their multiple SIMs. Thus, in this case, multiple SIMs on the UE share a single receiver system (or a single radio component). For these multi-SIM UEs, the UE may have to suspend an activity on one SIM while carrying out another higher priority activity on another SIM.

[0088] For example, UE 106 may be a dual SIM device, i.e., may contain two SIMs and may have a single receiver system for both SIMs. The first SIM may be configured with a preference for data transmission, and the second SIM may be configured with a preference for non-data communications (e.g., circuit switched (CS) communications or cellular voice calls).

[0089] In a common scenario, a first SIM (i.e., a data SIM) may be involved in data communications and may be operated in a connected mode with a network, for example, via a first radio resource control (RRC) connection. For example, the UE may actively perform data transfers using the first SIM via the first RRC connection, for example, for one or more applications on the UE, such as an Internet browsing application and / or one or more background applications. In this scenario, a second SIM, i.e., a non-data SIM instance, may be operated in an idle mode.

[0090] The UE may then receive a page or user input indicating a higher priority communication to be conducted via the second SIM. For example, the UE may receive a mobile station conditioned (MT) voice call from the network, a user of the UE may initiate a mobile station originating (MO) voice call, or the UE may receive or send an SMS (Short Message Service) message or other circuit switched (CS) communication.

[0091] In response to the indication of the higher priority communication on the second SIM, the UE may perform a local suspension of the first RRC connection of the first SIM, i.e. may suspend data communications on the first SIM to make the UE's receiver available for the higher priority communication on the second SIM.

[0092] When the higher priority communication on the second SIM is completed (for example, in the case of a voice call, because the user terminates the call), the second SIM may return to idle mode. The UE may then operate to resume the previously suspended first RRC connection using the first SIM.

[0093] Problems may arise at this point if the network is no longer synchronised with the UE regarding the state of the first RRC connection.

[0094] The resumption of the suspended first RRC connection may be performed according to a resumption sequence, for example, via an RRC connection reestablishment request. In some cases, the resumption sequence may not be synchronized with the network, which may have formed an incompatible perception of the first RRC connection after the first RRC connection was suspended. This lack of synchronization may affect throughput performance on the first SIM and may result in lost paging messages during the resumption and reestablishment process.

[0095] In some cases, the network may not have received appropriate indication that the first SIM has transitioned to idle mode (when the UE previously suspended communications on the first SIM) and therefore may not be prepared for the resume sequence.

[0096] In one set of undesirable scenarios, the network may include outdated information indicating that the first SIM is still in its original connected mode even after it has transitioned to idle mode. As a result, the network may attempt to page the UE on the first SIM, e.g. for an MT voice call, even though the UE is in idle mode. This may result in page misses and / or dropped or failed calls. The network may also waste network resources, such as uplink and downlink resources, by allocating these network resources to the first RRC connection (i.e., the first SIM on the UE), even though the first RRC connection is inactive and therefore unable or not ready to receive these communications.

[0097] In a second set of undesirable scenarios, at some point after the first SIM (i.e., the first RRC connection) transitions to idle mode, the network may have disconnected the first RRC connection with the first SIM. If the first SIM attempts to reestablish the first RRC connection in order to perform or resume certain data communications, the network may not be able to receive its communications. The UE may then need to perform a process of establishing a new connection with the network in order to perform these communications. As a result, the first SIM may not be able to quickly resume data communications via the first RRC connection. This may result in data transmission failures and long delays (increased waiting time) for the user of the UE.

[0098] Manufacturers and suppliers of multi-SIM and MUSIM devices have implemented various proprietary solutions to handle some of these scenarios and associated problems described above. However, these solutions must be validated and tuned for many different deployments around the world to ensure adequate performance, which can require a significant amount of work and resources. Therefore, improvements in the art are desired. In particular, 3GPP-defined solutions will be needed to address these and other issues.

[0099] UE instructs the network to suspend / update the operation for RRC state synchronization

[0100] In some embodiments, in scenarios such as described above, where a first SIM is suspended so that a second SIM can perform a higher priority task, the first SIM being suspended (or a software stack executing and using the first SIM) can use a "lightweight" mechanism (relatively small amount of signaling) to gracefully indicate to the NW that it is suspended for another high priority activity on another SIM instance.

[0101] Alternatively, during a resumption in which the second SIM has completed higher priority tasks and withdrawn use of the radio components, and the first SIM resumes connected state to resume its data transmission, the first SIM requesting resumption may notify the cellular network at a time after this resumption was locally suspended due to high priority activity on other SIM instances.

[0102] One motivation or goal of performing the above method is to avoid RRC state mismatch between the UE and the network, and more specifically, to avoid RRC state mismatch between the first SIM and the second SIM and their corresponding cellular networks.

[0103] In one embodiment, the first SIM that is about to be suspended can request a temporary transition to the RRC inactive state, and store and maintain the connection state or context of the SIM on the network side, while another high priority activity is completed on the first SIM. The connection state or context of the first SIM is stored and maintained on the network side, so that when the second SIM completes its higher priority task, the network can quickly restore the connection state of the first SIM.

[0104] For example, when storing UE context, we may point out herein that the NW may store one or more of the following: a UE identifier such as a UE ID (i.e., C-RNTI); the state the UE is in (e.g., connected); the time when SIM1 was suspended; and / or a packet data network (PDN), an evolved packet system (LTE) bearer, and / or a packet data unit (PDU) session established when the UE was in connected mode and its quality of service (QoS) and / or QoS flow identifier (QFI). Using this stored information, when the SIM1 connection is restored, the NW may allocate physical and transport channel resources to the UE for the PDN / EPS bearer / PDU session and the previously configured QoS / QFI, and may resume data transmission.

[0105] Since the network is now aware of the suspended state of the SIM, the transmission or communication of information about SIM suspension / resumption between the UE and the cellular network can result in fewer paging failures on the suspended SIM. In addition, these methods provide for faster and more efficient resumption of a suspended SIM, reducing the chances of the network rejecting the resume due to a potential RRC state mismatch,

[0106] These methods are described in more detail below.

[0107] Figure 6 —UE provides the network with an indication of RRC state synchronization (no timeout recovery)

[0108] Figure 6A message sequence chart is provided to illustrate a method for a UE having two SIMs to coordinate with (or provide indication to) the network regarding its SIM suspend / resume operations, thereby improving RRC state synchronization.

[0109] Figure 6 The message sequence chart shows various message transfers between a first communication software stack (UE stack 1, 602) operating with a first SIM, a second communication software stack (UE stack 2, 604) operating with a second SIM, a first cellular network (NW 1, 606), and a second cellular network (NW 2, 608). The first communication software stack (UE stack 1) operating with the first SIM can communicate with NW1, and the second communication software stack (UE stack 2) operating with the second SIM can communicate with NW 2. The term "communication software stack" refers to software executed on the UE that enables the UE to communicate with the network. In some embodiments, the UE maintains a communication software stack for each of the two SIMs, that is, the UE maintains a first communication software stack that is executed with the first SIM (SIM 1) to perform cellular communication using the first SIM, and the UE maintains a second communication software stack that is executed with the second SIM (SIM 1) to perform cellular communication using the second SIM.

[0110] As shown, at 610, UE stack 1 may be in RRC connected mode, performing data transmission with NW 1 using the radio (RF) of UE 106. NW 1 may also be in connected mode because it is communicating with UE stack 1. Since the UE contains only a single radio, while UE stack 1 is using that radio, at 612, UE stack 2 is in RRC idle mode.

[0111] At 614, a high priority activity is triggered on UE stack 2, wherein the high priority activity triggered on UE stack 2 requires suspension of current activity on UE stack 1. For example, UE stack 1 may be engaged in an RRC connected mode performing data transfer with NW 1, and a voice call may be activated on UE stack 2. In other words, a voice call may be initiated (or received) by the UE, wherein the voice call is processed by UE stack 2. For example, a mobile originating (MO) call may be made or placed by a user of the UE, wherein the MO call is processed using UE stack 2. Alternatively, a mobile terminated (MT) call may be received by the UE, wherein the MT call is processed using UE stack 2.

[0112] In response to the higher priority activity initiated on UE stack 2 , at 616 , UE stack 2 may send a pause request to UE stack 1 to notify UE stack 1 that it needs to suspend operations.

[0113] In response to the notification from UE stack 2, at 618, UE stack 1 may then transmit an RRC connection suspend request to the cellular network (NW 1) to which UE stack 1 is connected. The RRC connection suspend request may include information specifying a reason for the suspend request. More specifically, the RRC connection suspend request may include information specifying that the suspend request is due to a higher priority activity initiated on another SIM of the UE. The reason information may take the form of a code such as "MUSIM_High_Priority" or a similar form.

[0114] As shown, receiving an RRC connection suspend request from UE stack 1 may cause NW 1 to transmit an RRC connection suspend message back to UE stack 1 at 620. The RRC connection suspend message may include a code or instruction specifying that UE stack 1 should transition from a "connected" mode to an "inactive" mode. The code or instruction may take the form of "suspend_state=RRC_INACTIVE" or a similar form. The presence of this code in the RRC connection suspend message indicates that UE stack 1 enters an inactive state. In other words, the "suspend_state" code is used to indicate a new RRC state for UE stack 1. In other embodiments, the RRC connection suspend message may maintain the RRC connection in a "connected" mode, but with an extended DRX cycle configuration. For example, as Figure 6 Instead of transitioning UE stack 1 from “connected” mode to “inactive” mode as shown, the RRC connection suspend message at 620 may extend the DRX cycle duration and maintain the “connected” mode of UE stack 1 .

[0115] The RRC connection suspend message may also include code or instructions for specifying a timer duration for a suspend timer operating on the UE. The code or instruction may take the form of "suspend_timer_duration=X". As discussed further below, the suspend timer duration may specify the amount of time that the UE stack 1 will remain in the RRC inactive mode before transitioning to the RRC idle mode. Typical values ​​for the suspend timer duration may range from a few minutes or seconds to a few hours.

[0116] In response to UE stack 1 receiving the RRC connection suspend message from NW 1, UE stack 1 suspends at 622, and thus UE stack 1 may enter RRC inactive mode at 624 to facilitate or enable higher priority activities on UE stack 2. Receiving the RRC connection suspend message may also trigger the start of a suspension timer on the UE.

[0117] In some embodiments, NW 1 may also include a similar suspension timer, and the transmission of the RRC connection suspension message may cause NW 1 to start its own suspension timer. Thus, UE stack 1 (UE) and NW 1 may start their own respective suspension timers to determine how long the RRC connection between UE stack 1 and NW 1 remains in an inactive mode before timing out and transitioning to RRC idle mode.

[0118] As shown, triggering a high priority activity on UE stack 2 causes UE stack 2 to enter RRC connected mode at 626. UE stack 2 may then perform a higher priority activity at 628, such as a voice call.

[0119] exist Figure 6 In an exemplary embodiment of , the high priority activity (voice call) on UE stack 2 is completed before the suspension timer expires at 628. When the high priority activity on UE stack 2 is completed, UE stack 2 enters RRC idle mode at 630. Then, UE stack 2 may notify UE stack 1 at 632 that the high priority activity on UE stack 2 has been completed and UE stack 2 is now in idle mode. In response, UE stack 1 may transmit an RRC connection recovery request to NW 1 at 634. NW 1 receives the RRC connection recovery request and transmits an RRC connection reconfiguration message back to UE stack 1 at 636 in response. UE stack 1 receives the RRC connection reconfiguration message and enters RRC connection mode in response. Then, UE stack 1 transmits an RRC connection reconfiguration completion message back to NW 1 at 638, thereby entering RRC connection mode.

[0120] Figure 7 —Message flow chart—UE provides RRC status synchronization indication to the network (timeout recovery)

[0121] Figure 7 Message sequence chart showing a method for a UE having two SIMs to coordinate with (or provide indication to) the network regarding its SIM suspend / resume operations, thereby improving RRC state synchronization. Figure 6 , Figure 7 Communication between UE stack 1 702 and NW1 706 and communication between UE stack 2 704 and NW2 708 are described. Figure 7 and Figure 6 Similar, but different Figure 7 2 shows a situation where the pause timer expires before the high priority activity is completed on UE stack 2. For example, each of steps 710-726 may be similar to Figure 6 Steps 610-626 are performed.

[0122] However, starting from step 728, Figure 7The process shown in Figure 6 Specifically, the pause timer expires at 728 and UE stack 1 enters the RRC idle state at 730 before the high priority activity on UE stack 2 is completed at 732 .

[0123] Therefore, at 734, UE stack 1 may resume its connection with NW 1 at 734 by setting up a new RRC connection. At 738, UE stack 1 transmits an RRC connection resume request to NW 1. At 740, NW 1 responds to UE stack 1 with an RRC connection setup message, and UE stack 1 then responds to NW 1 with an RRC connection setup complete message at 742 to enter an RRC connected state with NW 1 at 744.

[0124] Figure 8 —The network stores the connection state context to keep the RRC state in sync

[0125] Figure 8 is a message sequence diagram showing an alternative implementation. Figure 6 and Figure 7 , Figure 8 The message sequence chart of shows various message transfers between a first communication software stack operating with a first SIM (SIM1) 802, a second communication software stack operating with a second SIM (SIM2) 804, and a cellular network (NW (SIM1)) 806 in communication with the first SIM. The first communication software stack operating with SIM1 may be in a connected mode 808, 812, using the radio (RF) of the UE 106 to perform data transfers with the NW (SIM1). As shown, the network NW (SIM1) is also in a connected mode because the network is communicating with the first communication software stack. Since the UE contains only a single radio, when the radio is being used by SIM1 (used by the first communication software stack operating with SIM1), then SIM2 (the second communication software stack operating with SIM2) is in an idle mode 810. In the following discussion, the term "SIM1" is used to refer to the first communication software stack operating in conjunction with SIM1, and similarly, "SIM2" is used to refer to the second communication software stack operating in conjunction with SIM2.

[0126] At 814, a voice call is initiated (or received) by SIM2. As shown in this example, a mobile originated (MO) call is made or initiated by a user of the UE, where SIM2 is used to make the MO call. In response to the MO call being initiated, SIM2 transmits a suspend request to SIM1 at 816. In response to the suspend request, SIM1 transmits an RRC suspend request to the cellular network NW(SIM1) to which SIM1 is connected at 818. Figure 6 and Figure 7In the embodiment of , receiving a suspend request from SIM1 will cause NW(SIM1) to transmit a suspend message back to SIM1, including an indication that SIM1 is to go to the inactive state and the timer duration value as described above. Figure 8 In an embodiment of the present invention, rather than transmitting such a suspension message back to the UE (SIM1), the network "freezes" the context (or connection state) of the current connected mode of SIM1 at 822. In other words, the network NW (SIM1) stores the current connected mode parameters / data related to the context or connection state of SIM1 in a memory, and saves the stored context for later use (in the resume connection mode). In addition, in response to receiving the suspension request from SIM1, the network also suspends or prevents the mobile station called (MT) call and downlink data transmission to SIM1 at 826. In other words, since the NW (SIM1) knows that SIM1 will be unreachable for a period of time, that is, SIM1 will not be able to receive communications for a period of time (because it is requesting to be suspended), the NW (SIM1) configures itself so that it will not send any downlink notification of paging to SIM1 for a period of time, and further so that the NW (SIM1) will not schedule any new data for SIM1. As an alternative to the above, for example, if the network does not support this feature, NW (SIM1) may send an RRC connection release message to SIM1 to put SIM1 into an inactive or idle state and suspend paging to SIM1, and NW (SIM1) may also enter a similar inactive or idle state.

[0127] In response to the MO call made using SIM2, SIM2 enters a connected state at 820 and performs a voice call, which may involve a second different cellular network. At 824, the voice call made using SIM2 ends, and SIM2 returns to an idle state at 828. After SIM2 returns to the idle state, SIM2 sends a resume request message to SIM1 at 830. In response to receiving the resume request from SIM1, SIM2 then sends an RRC resume request to NW(SIM1) at 832. The RRC resume request sent by SIM1 may include information indicating that this is a recovery from a situation involving a higher priority connection that requires another SIM on the UE to assume control of the radio component. When the network NW(SIM1) receives the RRC resume request from SIM1, the network may respond in one of a number of different ways.

[0128] In one embodiment, the NW (SIM1) may restore the connection state or context of the previous connected mode connection at 834, i.e., the connection state that had been previously "frozen" at step 822. This enables the previous connected mode to be "resumed" from where it left off. The NW (SIM1) may also resume (or suspend) the mobile station call and downlink data transmission to SIM1. The NW (SIM1) may also send an RRC resume message to SIM1 at 838 to inform SIM1 that the previous connected mode has been resumed. Therefore, in this embodiment, the NW (SIM1) and SIM1 may both return to connected mode (connected state) at 840 and 842, and data transmission, MT calls, and paging are now operable as they would normally be in connected mode.

[0129] In another embodiment, it may be the case that a long period of time has passed during which the connection with SIM1 has been suspended. For example, an MO voice call performed by SIM2 may last for more than a specified period of time (e.g., determined by a timer used for this purpose). In this case, the NW (SIM1) may have discarded the stored connection mode context when the timer expired (and then, of course, the network will no longer have the stored connection mode parameters to restore). In this case, when this specific period of time has passed, the NW (SIM1) may transition to an idle or inactive mode at 844, 846 and discard (no longer store) the previously stored connection mode context. The NW (SIM1) may also transmit an RRC connection release message to SIM1 at 848. The message may also indicate to SIM1 that it should also transition to an idle mode, which may be performed at 850. In this case, it may be necessary to re-establish a new connection between SIM1 and the NW (SIM1) in order to enable data communication between them.

[0130] An important benefit of the above approach is that this ensures that there are no differences in the RRC state between the network and the UE. In addition, the network suspends paging and downlink data to the suspended SIM, thereby preventing any problems associated with attempting to communicate with a suspended device. In addition, the network maintains full control of the UE's RRC state, so the network ensures that both SIMs of the UE remain synchronized with the network's RRC state, i.e., the SIM's RRC state always matches the network's RRC state.

[0131] RRC state mismatch in 5G NR

[0132] Fig. 9 is a message sequence diagram illustrating problems that may arise in some existing implementations of DSDS devices. Figures 6 to 8 , Fig. 9The message sequence diagram shows various message transfers between a first communication software stack operating with a first SIM (SIM1 902), a second communication software stack operating with a second SIM (SIM2 904), and a cellular network (NW (SIM1) 906) communicating with the first SIM. However, Fig. 9 It may be more specifically applicable to 5G NR implementations utilizing an RRC inactive state. A first communication software stack operating with SIM1 may be in a connected mode 908, performing data transmission with NW (SIM1) using the radio component (RF) of UE 106. As shown, the network NW (SIM1) is also in a connected mode 912 because the network is communicating with the first communication software stack. Since the UE contains only a single radio component, when the radio component is being used by SIM1 (used by the first communication software stack operating with SIM1), SIM2 (the second communication software stack operating with SIM2) is in an idle mode 910. In the following discussion, the term "SIM1" is used to refer to the first communication software stack operating in conjunction with SIM1, and similarly, "SIM2" is used to refer to the second communication software stack operating in conjunction with SIM2.

[0133] At 914, NW(SIM1) may transmit an RRC connection release message to SIM1 to convert the connection between SIM1 and NW(SIM1) from connected mode to inactive mode. SIM1 and NW(SIM1) may then convert both their mutual connections to inactive mode.

[0134] At 918, a voice call is initiated (or received) by SIM2. As shown in this example, a mobile originated (MO) call is made or initiated by a user of the UE, where SIM2 is used to make the MO call, which may be a high priority call. In response to the MO call being initiated, SIM2 transmits a suspend request 922 to SIM1 to indicate that SIM2 wants to take over the UE's RF chain to enable the MO call.

[0135] At 924, SIM2 may enter into a connection with its cellular network (eg, NW(SIM2), Fig. 9 SIM2 and NW (SIM2) may be in an RRC connected state (not shown) and may make a MO call with a remote entity through NW (SIM2). The MO call may be made for a long period of time (e.g., several hours or another long period of time) before the call ends at 926 and the connection between SIM2 and NW (SIM2) transitions to an idle state at 928.

[0136] After SIM1 receives the resume request from SIM2 at 930, one of two alternative processes may occur, which are shown in the two large boxes corresponding to steps 932-942 and steps 944-952, respectively. In the first alternative, when SIM1 receives the resume request from SIM2 at 930, the UE may assume that it is in an inactive state 934 with the NW (SIM1), while the NW (SIM1) assumes that the UE is in an idle state 936. In other words, there may be a mismatch between the UE and the NW (SIM1)'s understanding of the connection state between SIM1 and the NW (SIM1). As an example, an MO call on SIM2 may last long enough for the NW (SIM1) to abandon the context associated with its connection with SIM1 and transition the connection to an idle state, while the UE believes that the connection is in an inactive state. For example, the NW (SIM1) may have attempted to page SIM1 during the SIM2 call and may have timed out the connection with SIM1 due to not receiving a timely response from SIM1. In these embodiments, SIM1 may have UL data to transmit at 938, and may transmit an RRC resume request with an inactive radio network temporary identifier (I-RNTI) indicator to NW (SIM1) to resume transmission of the UL data at 940. However, because NW (SIM1) no longer maintains the context of the connection, NW (SIM1) may respond with an RRC release message at 942 to release the RRC connection, thereby increasing latency for UL transmissions.

[0137] In the second alternative illustrated with reference to steps 944-952, there may be an alternative mismatch between the assumptions of the connection state of SIM1 and NW(SIM1). For example, the UE may assume that the connection between SIM1 and NW(SIM1) has been terminated and is in an idle state at 946, while NW(SIM1) may maintain the connection context in an inactive mode at 948. In these embodiments, if SIM1 has UL data to be transmitted to NW(SIM1) at 950, it may transmit an RRC connection request to NW(SIM1) at 952 to establish a new connection, thereby incurring high latency during the establishment of the new RRC connection. The embodiments described below provide methods and apparatus that reduce latency and battery consumption introduced in these two alternatives.

[0138] Using the Pause Timer to Avoid RRC State Mismatch

[0139] Fig.10 To illustrate a message sequence diagram according to some embodiments, the message sequence diagram illustrates a method and apparatus for enhancing the operation of a DSDS device using a pause timer. More specifically, Fig.10 is a message sequence diagram, which solves the Fig. 9 Some restrictions and waiting times are introduced in the message sequence diagram shown in . Figures 6 to 9 , Fig.10 The message sequence diagram shows various message transfers between a first communication software stack operating with a first SIM (SIM1 1002), a second communication software stack operating with a second SIM (SIM2 1004), and a cellular network (NW(SIM1) 1006) communicating with the first SIM. However, Fig.10 It may be more specifically applicable to 5G NR implementations utilizing an RRC inactive state. A first communication software stack operating with SIM1 may be in a connected mode 1008, performing data transmission with NW (SIM1) using a radio component (RF) of UE 106. As shown, the network NW (SIM1) is also in a connected mode 1012 because the network is communicating with the first communication software stack. Since the UE contains only a single radio component, when the radio component is being used by SIM1 (used by the first communication software stack operating with SIM1), SIM2 (the second communication software stack operating with SIM2) is in an idle mode 1010. In the following discussion, the term "SIM1" is used to refer to the first communication software stack operating in conjunction with SIM1, and similarly, "SIM2" is used to refer to the second communication software stack operating in conjunction with SIM2.

[0140] Fig.10 Steps 1008-1022 can be Fig. 9 Steps 908-922 of SIM1 are similarly operated, whereby the connection between SIM1 and NW (SIM1) is converted from the connected state to the inactive state. Alternatively, in some embodiments, the network may not support the inactive state, and the connection between SIM1 and NW (SIM1) may be converted to the idle state ( Fig.10 (not shown). Alternatively, in other embodiments, the RRC connection release message may maintain the RRC connection in connected mode, but with an extended DRX cycle configuration. Fig.10 Instead of switching SIM1 from connected mode to inactive mode, the RRC connection release message at 1014 can extend the DRX cycle duration and maintain the connected mode of SIM1. Subsequently, SIM2 switches its connection with NW (SIM2) away from idle state to initiate an MO call, and SIM2 sends a suspend request to SIM1 to gain access to the shared RF chain of the UE. However, Fig.10 The next steps deviate Fig. 9 Steps shown.

[0141] Specifically, at 1024, SIM1 may transmit an RRC suspend request to NW (SIM1) with a MUSIM_suspended cause indication to indicate to NW (SIM1) that SIM1 is entering a suspended inactive state. At 1026, NW (SIM1) may respond by transmitting an RRC connection release message to SIM1 with an RRC_Inactive indication, an I-RNTI, and / or an indication of a suspension timer duration. Both the UE and NW (SIM1) may start a suspension timer in response to the transmission of the RRC connection release at step 1026, and SIM2 may establish a connected state with NW (SIM2) at 1028 for an MO call.

[0142] Subsequently, one of two alternative processes may be implemented, depending on whether the MO call on SIM2 has ended upon expiration of the pause timer, as described in connection with steps 1030-1036 and 1038-1056, respectively. Fig.10 The two large boxes are described.

[0143] In a first alternative, the suspension timer may expire, and the SIM2 call may end at 1030 after the suspension timer expires. At 1032, SIM2 may transmit a resume request to SIM1. However, because the suspension timer has expired, the UE may be aware that the connection between SIM1 and the NW (SIM1) has been terminated, and both the UE and the NW (SIM1) may consider their connections to be in an idle state. Therefore, in order to resume communication with the NW (SIM1) through SIM1, SIM1 may initiate a new RRC connection with the NW (SIM1) without causing a mismatch in the connection state between the UE and the NW (SIM1).

[0144] In a second alternative, the SIM2 call may end at 1038, and the connection between SIM2 and the NW (SIM2) may enter an idle state at 1040 before the suspension timer expires. In these embodiments, SIM2 may transmit a resume request to SIM1 at 1044, and SIM1 may assume that the connection between SIM1 and the NW (SIM1) remains in an inactive state at 1046. Therefore, at 1050, SIM1 may transmit an RRC resume request to the NW (SIM1), including an I-RNTI and a nextStatePreference indicator. The nextStatePreference indicator may indicate the UE's preferred state for the connection between SIM1 and the NW (SIM1). For example, if the UE has remaining UL data to be transmitted through SIM1, it may request that the SIM1 / NW (SIM1) connection be transitioned to a connected state to transmit the UL data. If the UE has no other data to transmit through SIM1, the nextStatePreference indicator may indicate a preference for an inactive state or an idle state according to various embodiments. Because NW (SIM1) also maintains the suspend timer, when it receives the RRC resume request from SIM1, it maintains the connection context with SIM1 in an inactive state. Therefore, according to the nextStatePreference indicator and / or network-side considerations, NW (SIM1) may respond to SIM1 with an RRC resume or RRC connection release message. At 1054 and 1056, SIM1 and NW (SIM1) may continue to operate according to the next state (e.g., connected mode, inactive mode, or idle mode).

[0145] Network coordination to avoid RRC state mismatch

[0146] Fig.11 To illustrate a message sequence diagram according to some embodiments, the message sequence diagram illustrates a method and apparatus for enhancing the operation of a DSDS device using network-side coordination. More specifically, Fig.11 A message sequence chart for improving the RRC connection state matching between the network and the UE of a DSDS device using network-side coordination. Figures 6 to 10 , Fig.11 The message sequence chart shows various message transfers between a first communication software stack operating with a first SIM (SIM1 1102), a second communication software stack operating with a second SIM (SIM2 1104), a first cellular network (NW(SIM1) 1106) communicating with the first SIM, and a second cellular network (NW(SIM2) 1108) communicating with the second SIM. Fig.11It may be more specifically applicable to 5G NR implementations utilizing an RRC inactive state. A first communication software stack operating with SIM1 may be in a connected mode 1110, performing data transfers with NW (SIM1) using a radio component (RF) of UE 106. As shown, the network NW (SIM1) is also in a connected mode 1114 because the network is communicating with the first communication software stack. Since the UE contains only a single radio component, when the radio component is being used by SIM1 (used by the first communication software stack operating with SIM1), then SIM2 (the second communication software stack operating with SIM2) is in an idle mode 1112, and NW (SIM2) may similarly be in an idle mode 1116 with respect to its connection with SIM2. In the following discussion, the term "SIM1" is used to refer to the first communication software stack operating in conjunction with SIM1, and similarly, "SIM2" is used to refer to the second communication software stack operating in conjunction with SIM2.

[0147] Fig.11 Steps 1110-1126 can be Fig. 9 Steps 908-922 and Fig.10 Steps 1008-1022 of SIM1 are similarly operated, whereby the connection between SIM1 and NW (SIM1) is converted from the connected state to the inactive state. Alternatively, in some embodiments, the network may not support the inactive state, and the connection between SIM1 and NW (SIM1) may be converted to the idle state ( Fig.11 SIM2 then switches its connection with NW (SIM2) away from idle state to initiate a MO call, and SIM2 sends a suspend request to SIM1 to gain access to the shared RF chain of the UE. Fig.11 The next steps deviate Fig. 9 and Fig.10 Steps shown.

[0148] Specifically, at 1128, SIM2 may initiate an RRC connection establishment process with NW (SIM2) and enter an RRC connected state at 1130. At 1132, NW (SIM2) may notify NW (SIM1) that the inactive mode connection between SIM1 and NW (SIM1) should enter a suspended inactive state. In response, at 1134, NW (SIM1) may freeze its inactive mode connection with SIM1 and start a protection timer.

[0149] Subsequently, one of two alternative processes may be implemented, depending on whether the MO call on SIM2 has ended upon expiration of the protection timer, as described in connection with steps 1136-1152 and 1154-1166, respectively. Fig.11 The two large boxes are described.

[0150] In a first alternative, the SIM2 call may end at 1138 and 1140 before the suspension timer expires. At 1142, NW(SIM2) may send a resume indication to NW(SIM1) indicating that NW(SIM1) may resume its connection with SIM1. In response, at 1144, NW(SIM1) may transmit a SIM1 state indicator to NW(SIM2) indicating a preferred RRC state for resuming its connection with SIM1. For example, Fig.11 In the SIM1 state indicator, the preference for the RRC inactive state is indicated, but the NW (SIM1) may also indicate a preference for the RRC connected state or the RRC idle state as required.

[0151] At 1146, NW (SIM2) may transmit an RRC connection release message to SIM2 to release the connection between NW (SIM2) and SIM2 so that SIM2 may enter idle mode. Importantly, NW (SIM2) may include a SIM1 preferred state indicator in the RRC connection release message to inform SIM2 of the preferred RRC state of the connection between SIM1 and NW (SIM1). Advantageously, this may preserve state coordination between SIM1 and NW (SIM1) without consuming additional radio resources by sending coordination messages between SIM1 and NW (SIM1).

[0152] At 1148, SIM2 may send a resume request to SIM1 indicating that SIM2 is retracting RF chain access to the UE to SIM1, and may include a SIM1 preferred state indicator in the resume request (e.g., SIM2 indicates to SIM1 that NW(SIM1) wants to Fig.11 1, although the SIM1 preferred state indicator may also indicate a preference for connected mode or idle mode as desired). Finally, at 1150 and 1152, both SIM1 and NW (SIM1) may resume their connection without pausing, based on the preferred state indicator. Thus, communication through SIM1 with NW (SIM1) may be resumed without causing a mismatch in the connection state between the UE and NW (SIM1).

[0153] In the second alternative described with reference to steps 1154-1166, the protection timer may expire first, and the SIM2 call may end at 1156 after the suspension timer expires. At 1158, NW(SIM1) may transition its connection with SIM1 from an inactive state to an idle state in response to the expiration of the protection timer. At 1160, after the call between SIM2 and NW(SIM2) ends at 1156, NW(SIM2) may send a SIM1 resume indicator to NW(SIM1) indicating that NW(SIM2) has ended its MO call with SIM2 so that NW(SIM1) may resume its connection with SIM1. However, since NW(SIM1) has entered idle mode with respect to its connection with SIM1 and no longer maintains the context of the connection, NW(SIM1) responds to NW(SIM2) with a preferred SIM1 state indicator indicating a preference for the RRC idle state. Similar to step 1146 described above, at 1164, NW (SIM) sends an RRC connection release message to SIM2, including a SIM1 preferred state indicator indicating a preference for SIM1 to enter the idle state. Finally, at 1142, SIM2 may send a resume request to SIM1, indicating that SIM2 is withdrawing RF chain access to the UE to SIM1, and also including a SIM1 preferred state indicator for the idle state, whereupon SIM1 enters the idle state at 1166. Therefore, both SIM1 and NW (SIM1) will transition to the idle state, thereby avoiding state mismatches regarding their connections without explicitly sending coordination messages between SIM1 and NW (SIM1).

[0154] Fig.12 —UE notifies the network of connection release

[0155] Fig.12 is a message sequence diagram showing an alternative implementation. Figures 6 to 11 , Fig.121204, a cellular network in communication with the first SIM (NW (SIM1)) 1206, and a cellular network in communication with the second SIM (NW (SIM2)) 1208. The first communication software stack in communication with SIM1 may be in a connected mode 1210, 1214, performing continuous data transmission 1216 with NW (SIM1) using the radio (RF) of the UE 106, while SIM2 is in an idle state with respect to its connection with NW (SIM2). As shown, the network NW (SIM1) is also in a connected mode because the network is communicating with the first communication software stack of SIM1. Since the UE contains only a single radio, when the radio is being used by SIM1 (used by the first communication software stack in communication with SIM1), then SIM2 (the second communication software stack in communication with SIM2) is in an idle mode 1210. In the following discussion, the term "SIM1" is used to refer to a first communication software stack operating in conjunction with SIM1, and similarly, "SIM2" is used to refer to a second communication software stack operating in conjunction with SIM2.

[0156] In some embodiments, when the non-data preferred SIM (e.g., SIM1) ends the voice call, it withdraws the UE's RF chain to the data preferred SIM (e.g., SIM2) so that SIM2 can continue the data transfer process that was suspended due to the SIM1 voice call. In this case, there may be an RRC state mismatch between SIM1 and NW (SIM1) because the UE can usually perform a local release of the RRC connection only on SIM1 and may cause a mismatch with the NW (SIM1). Subsequently, if the MO user triggers a back-to-back voice call on SIM1, the second call may be missed due to the RRC state mismatch. To address these and other issues, Fig.12 A method is provided for the UE to notify the NW of connection release to avoid potential RRC state mismatch.

[0157] While data transmission 1216 is in progress between SIM1 and NW(SIM1), SIM2 may initiate or receive a high priority call at 1218. In response, SIM2 may send a suspend request to SIM1 at 1220 so that SIM2 may gain access to the radio components of the UE. SIM2 may then establish a connection with NW(SIM2) at 1224 and 1226 for the high priority call, and SIM1 may enter a suspended state at 1222.

[0158] The high priority call may end at 1228, and SIM2 may send a signaling connection release indication to NW(SIM2) at 1230 to notify the network that SIM2 enters an idle state at 1232. Accordingly, in response to receiving the signaling connection release indication from SIM2, NW(SIM2) may also enter an idle state with respect to its connection SIM2, so that SIM2 and NW(SIM2) are synchronized with respect to their mutual connection states.

[0159] At 1236 , in response to entering the idle state, SIM2 may send a resume request to SIM1 so that SIM1 may resume its connection with the NW ( SIM1 ), and SIM1 may attempt to reestablish its RRC connection with the NW ( SIM1 ) at 1238 .

[0160] At this point, one of two alternative implementations may be implemented, depending on whether the attempt to reestablish the connection between SIM1 and NW (SIM1) is successful. If the reestablishment of the connection is successful 1240, the connection may be established at 1242 and 1244, and SIM1 and NW (SIM1) may continue to transmit data in the uplink and / or downlink. Alternatively, if the attempt to reestablish the connection between SIM1 and NW (SIM1) is unsuccessful at 1248, both SIM1 and NW (SIM1) may enter an idle state with respect to their mutual connection.

[0161] At 1254, NW(SIM2) may be notified of SIM2's incoming call at 1254, and NW(SIM2) may page SIM2 in idle mode for a mobile called (MT) call at 1256. Thus, SIM2 may establish the MT call at 1258.

[0162] The following paragraphs describe additional embodiments of the invention.

[0163] A cellular network device may include a processing element; and a memory coupled to the processing element; wherein the cellular network device is configured to: establish a first radio resource control (RRC) connection with a first software communication stack of a user equipment (UE), wherein the first software communication stack uses a first user identity module (SIM) of the UE; receive a radio resource control (RRC) connection suspension request from the first software communication stack of the UE, wherein the RRC connection suspension request includes information specifying that the reason for the suspension request is a higher priority cellular communication of a second software communication stack using a second SIM of the UE; and store a connection state of the RRC connection of the first software communication stack of the UE, wherein the stored connection state can be used to resume the RRC connection later.

[0164] In some embodiments, the cellular network device may also be configured to: receive an RRC resumption request from the UE's first software communication stack, wherein the RRC resumption request is received within a period of time after receiving the RRC connection suspension request; and restore the stored connection state of the RRC connection with the UE's first software communication stack.

[0165] In some embodiments, the cellular network device may also be configured to stop transmitting downlink data to the UE in response to receiving the RRC connection suspend request.

[0166] In other embodiments, a cellular network entity may include a radio component comprising one or more antennas for performing wireless communications; and a processing element operatively coupled to the radio component; wherein the cellular network entity is configured to: establish a first radio resource control (RRC) connection with a first subscriber identity module (SIM) of a user equipment device (UE), wherein the first RRC connection is in an inactive mode; receive a first notification from a second cellular network entity to suspend the first RRC connection; in response to receiving the first notification, suspend the first RRC connection and start a protection timer; receive a second notification from the second cellular network entity to resume the first RRC connection; transmit a preferred state indicator indicating a preferred state for resuming the first RRC connection to the second cellular network entity; and resume the first RRC connection with the first SIM of the UE according to the preferred state.

[0167] In some embodiments, the cellular network is operable such that the second indication is received after expiration of the timer and the preferred state indicator indicates a preference for the RRC idle state.

[0168] In some embodiments, the cellular network is operable such that the second indication is received prior to expiration of the timer and the preferred state indicator indicates a preference for the RRC inactive state or the RRC connected state.

[0169] In some embodiments, a wireless user equipment (UE) device includes a radio component, the radio component including one or more antennas for performing wireless communications, a processing element operatively coupled to the radio component, and a first and a second user identity module (SIM). Each of the first SIM and the second SIM is coupled to the radio component and is configured to be used with the radio component for wireless communications, wherein at any given time, only one of the first SIM and the second SIM is used with the radio component. The UE may be configured to use the first SIM and the first radio resource control (RRC) connection to perform cellular data communications with a first cellular network; and receive a request to perform a higher priority cellular communication with a second cellular network using the second SIM. In response to the request to perform a higher priority cellular communication using the second SIM, the UE may suspend the first RRC connection and may use the second SIM for a higher priority cellular communication with the second cellular network. When the higher priority cellular communication is completed, the UE may send a release indication to the second network, and the UE may resume the first RRC connection with the first SIM.

[0170] It is understood that the use of personally identifiable information should be subject to privacy policies and practices that are generally recognized to meet or exceed industry or government requirements for maintaining user privacy. Specifically, personally identifiable information data should be managed and processed to minimize the risk of unintentional or unauthorized access or use, and the nature of the authorized use should be clearly stated to users.

[0171] The embodiments of the present disclosure may be implemented in any of a variety of forms. For example, some embodiments may be implemented as computer-implemented methods, computer-readable storage media, or computer systems. Other embodiments may be implemented using one or more custom-designed hardware devices such as ASICs. Other embodiments may be implemented using one or more programmable hardware elements such as FPGAs.

[0172] In some embodiments, a non-transitory computer-readable storage medium may be configured such that it stores program instructions and / or data, wherein if the program instructions are executed by a computer system, the computer system is caused to perform a method, such as any one of the method embodiments described herein, or any combination of the method embodiments described herein, or any subset of any method embodiments described herein, or any combination of such subsets.

[0173] In some embodiments, the computer system may be configured to include a processor (or a group of processors) and a memory medium, wherein the memory medium stores program instructions, wherein the processor is configured to read and execute program instructions from the memory medium, wherein the executable program instructions are to implement any of the various method embodiments described herein (or any combination of the method embodiments described herein, or any subset of any method embodiments described herein, or any combination of such subsets). The computer system may be implemented in any of various forms. For example, the computer system may be a personal computer (in any of its various implementations), a workstation, a computer on a card, a dedicated computer in a box, a server computer, a client computer, a handheld device, a user device (UE), a tablet computer, a wearable computer, etc.

[0174] Although the above embodiments have been described in considerable detail, numerous variations and modifications will become apparent to those skilled in the art once the above disclosure is fully appreciated. It is intended that the following claims be interpreted to encompass all such variations and modifications.

Claims

1. A wireless user equipment device UE, the UE comprising: a radio component including one or more antennas for performing wireless communications; a processing element operatively coupled to the radio; and a first subscriber identity module SIM and a second subscriber identity module SIM, wherein each of the first SIM and the second SIM is coupled to the radio component and configured for wireless communication with the radio component; The UE is configured as follows: Determining to use the second SIM to perform cellular communication; In response to determining to use the second SIM to perform the cellular communication, determining to leave a first radio resource control (RRC) connection; receiving a message from a first cellular network to release the first RRC connection and to change the RRC state associated with the first SIM from a first RRC state to a second RRC state; performing the cellular communication using the second SIM; as well as After performing the cellular communication using the second SIM, a message is sent to the first cellular network, the message indicating an RRC resume request and a preferred next RRC state selected from the group consisting of an RRC Connected state, an RRC Inactive state, and an RRC Idle state.

2. The UE according to claim 1, The preferred next RRC state is selected from the group consisting of the RRC Connected state, the RRC Inactive state, and the RRC Idle state based on pending uplink data at the UE.

3. The UE according to claim 1, One or more of the first SIM and the second SIM are embedded SIMs, and the embedded SIM uses an embedded memory in the UE to store user information related to the one or more of the first SIM and the second SIM.

4. The UE according to claim 1, wherein the UE leaves the first RRC state based on paging received in the UE, and Wherein the page is received from a second cellular network for the second SIM.

5. The UE according to claim 1, The determination to leave the first RRC state is derived from user input.

6. The UE according to claim 1, Wherein the first RRC state is the RRC_Connected state, and wherein the second RRC state is one of the RRC_Idle state or the RRC_Inactive state.

7. The UE according to claim 1, The UE is further configured as follows: The RRC state associated with the second SIM is transitioned from a third RRC state to a fourth RRC state.

8. The UE according to claim 7, The third RRC state is one of the RRC_Idle state or the RRC_Inactive state.

9. The UE according to claim 7, The fourth RRC state is the RRC_Connected state.

10. A device, comprising: A processor, the processor being configured to: Determining to use the second SIM to perform cellular communication; In response to determining to use the second SIM to perform the cellular communication, sending a request to the first cellular network to release the first radio resource control (RRC) connection; receiving a message from the first cellular network to release the first RRC connection and to change the RRC state associated with the first SIM from a first RRC state to a second RRC state; performing the cellular communication using the second SIM; as well as After performing the cellular communication using the second SIM, a preferred next state indication is sent to the first cellular network, the preferred next state indication indicating a preferred next RRC state selected from the group consisting of an RRC Connected state, an RRC Inactive state, and an RRC Idle state.

11. The apparatus of claim 10, wherein the preferred next RRC state is selected from the group consisting of the RRC Connected state, the RRC Inactive state, and the RRC Idle state based on pending uplink data at the UE.

12. The device according to claim 10, One or more of the first SIM and the second SIM are embedded SIMs, and the embedded SIM uses an embedded memory in the UE to store user information related to the one or more of the first SIM and the second SIM.

13. The apparatus of claim 10, wherein the processor is further configured to: receiving a page from a second cellular network for the second SIM, and Wherein the determination to leave the first RRC state is based on the paging.

14. The device according to claim 10, The determination to leave the first RRC state is derived from user input.

15. The device according to claim 10, Wherein the first RRC state is the RRC_Connected state, and wherein the second RRC state is one of the RRC_Idle state or the RRC_Inactive state.

16. A method for operating a user equipment device UE, the method comprising: performing cellular data communications with a first cellular network using a first subscriber identity module SIM of the UE and a first RRC connection in a first radio resource control, RRC, state associated with the first SIM; Determining to use the second SIM to perform cellular communication; In response to determining to use the second SIM to perform the cellular communication, determining to leave the first RRC state; In response to determining to leave the first RRC state, sending a request to the first cellular network to release the first RRC connection; receiving a message from the first cellular network to release the first RRC connection and to change the RRC state associated with the first SIM from the first RRC state to a second RRC state after sending the request to release the first RRC connection; performing the cellular communication using the second SIM; as well as After performing the cellular communication using the second SIM, a preferred next state indication is sent to the first cellular network, the preferred next state indication indicating a preferred next RRC state selected from the group consisting of an RRC Connected state, an RRC Inactive state, and an RRC Idle state.

17. The method of claim 16, wherein the preferred next RRC state is selected from the group consisting of the RRC Connected state, the RRC Inactive state, and the RRC Idle state based on pending uplink data at the UE.

18. The method according to claim 17, One or more of the first SIM and the second SIM are embedded SIMs, and the embedded SIM uses an embedded memory in the UE to store user information related to the one or more of the first SIM and the second SIM.

19. The method according to claim 17, Wherein the first RRC state is the RRC_Connected state, and wherein the second RRC state is one of the RRC_Idle state or the RRC_Inactive state.

20. The method according to claim 17, further comprising: transitioning the RRC state associated with the second SIM from a third RRC state to a fourth RRC state, wherein the third RRC state is one of the RRC_Idle state or the RRC_Inactive state, and The fourth RRC state is the RRC_Connected state.

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