UE with multiple subscriber identity modules with improved suspend / resume operations

Abstract

The present disclosure relates to UEs with multiple user identity modules with improved suspend / resume operations. The present disclosure provides apparatuses and related methods for operating a dual subscriber identity module (SIM) dual standby (DSDS) user equipment device (UE) configured with 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 a higher priority communication using the second SIM. In response to the request to perform the higher priority communication, 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, where the timer is used to determine whether the first RRC connection is to remain in the inactive state or transition to an idle state.

Description

[0001] This application is a divisional application of the invention patent application filed on July 10, 2019, with application number 201910618956.0, entitled "UE with multiple user identity modules having improved pause / resume operation". Technical Field

[0002] This disclosure relates to the field of wireless communications, and more specifically to a user equipment (UE) having multiple user identity modules that performs improved network notifications during SIM suspension / resumption operations. Background Technology

[0003] The use of wireless communication systems is growing rapidly. Furthermore, wireless communication technology has evolved from voice communication only to include the transmission of data, such as the internet and multimedia content. To enable wireless devices to access wireless communication networks (e.g., cellular telecommunications networks) according to at least some wireless communication technologies and standards, users can subscribe to service providers (“operators”), who can then provide such services to users, for example, via the wireless communication networks they operate. Such users in wireless communication networks 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 have a slot for a removable Subscriber Identity Module (SIM) card. Providing such a slot allows users to select and / or change their user identity independently of the wireless device, as users can 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 embedded memory within 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 the user. This allows the UE to store, for example, the user's home phone number as a first set of user identity information, and also the user's business phone number as a second set of user identity information. Alternatively or otherwise, one SIM can be primarily used for voice calls, while the other can be primarily used for data transmission. Dual-SIM or multi-SIM UE devices are particularly popular in recently developing economies such as China.

[0005] One type of dual-SIM UE is called Dual User Identity Module Dual Communicator (DSDA) and can include a multiple receiver (Rx) architecture. A DSDA UE can use two SIMs and two radio components to maintain two sets of active data communications simultaneously. For example, the UE can use one SIM for voice calls 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., for cost savings and reduced size requirements) and may be referred to as Dual User Identity Module Dual Standby (DSDS). In a UE containing only a single receiver, only one SIM may be active at any given time. Therefore, 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 requiring the other SIM, the UE may suspend activity on the first SIM to perform the higher-priority activity on the other SIM. In a UE with multiple SIM devices and only one radio component, the UE may encounter network problems when the SIM is suspended and then the radio resource control (RRC) connection to the network is subsequently restored.

[0007] Therefore, improvements in wireless communication, especially in relation to multi-user identity functionality, are desirable. Summary of the Invention

[0008] In view of the foregoing and other considerations, it is desirable to expand the functionality of wireless devices regarding user identity. Specifically, it is desirable to provide improved state synchronization between wireless devices and networks in an energy-efficient manner. This disclosure relates to such techniques for facilitating state synchronization according to various embodiments.

[0009] Therefore, embodiments of this 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-transitory computer-accessible memory medium storing program instructions executable by a processor to implement such a method. The UE device may include radio components 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 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. Additionally, the UE device may include a non-transitory computer-accessible memory medium that stores program instructions executable by the UE.

[0010] In some implementations, the DSDS UE is configured to have a first SIM and a second SIM. The UE uses the first SIM and a first Radio Resource Control (RRC) connection to perform communications with a first cellular network, and uses the second SIM to receive requests to perform higher-priority communications. 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 an inactive state or transitions to an idle state. Attached Figure Description

[0011] A better understanding of the subject matter of this disclosure can be obtained by considering the following detailed description of preferred embodiments in conjunction with the accompanying drawings, wherein:

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

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

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

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

[0016] Figure 6 To illustrate an exemplary method according to some implementations, a message sequence diagram is provided, in which the UE provides the network with information about pausing / resuming operations to maintain RRC state synchronization, wherein the resumption is performed without a timeout event;

[0017] Figure 7 To illustrate an exemplary method according to some implementations, a message sequence diagram is provided, in which the UE provides the network with information about pausing / resuming operations to maintain RRC state synchronization, wherein resumption is performed in the event of a timeout event;

[0018] Figure 8 To illustrate an exemplary method according to some implementations, a message sequence diagram is provided, in which the UE provides information to the network about pause / resume operations, and the network stores connection state information to keep RRC state synchronized;

[0019] Figure 9 To illustrate the message sequence diagram of the problem arising from the RRC state mismatch;

[0020] Figure 10 To illustrate an exemplary method according to some implementations, a message sequence diagram is provided, in which a pause timer is used to avoid RRC state mismatch;

[0021] Figure 11 To illustrate a message sequence diagram of an exemplary method according to some implementations, wherein network coordination is utilized to avoid RRC state mismatch; and

[0022] Figure 12 The following is a message sequence diagram illustrating an exemplary method according to some implementations, in which the UE notifies the network connection to be released to avoid an RRC state mismatch.

[0023] While the features described herein are susceptible to various modifications and alternatives, specific embodiments thereof are shown by way of example in the accompanying drawings and are described in detail herein. However, it should be understood that the drawings and the detailed description thereof are not intended to limit this document to the specific forms disclosed, but rather are intended to cover all modifications, equivalents, and alternatives falling within the substance and scope of the subject matter as defined by the appended claims. Detailed Implementation

[0024] acronym

[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: Advanced LTE

[0032] SIM: User Identity Module

[0033] eSIM: Embedded SIM

[0034] IMSI: International Mobile Subscriber Identity

[0035] MCC: Country Code for Mobile

[0036] MNC: Mobile Network Code

[0037] the term

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

[0039] Memory media—any of various types of memory devices or storage devices. The term "memory media" is intended to include mounting media such as CD-ROMs, floppy disks, or magnetic 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, such as hard disk drives or optical storage devices; registers, or other similar types of memory elements, etc. Memory media may also include other types of memory, or combinations thereof. Furthermore, memory media may reside in a first computer system executing a program, or may reside 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 media" may include two or more memory media that may reside in different locations on different computer systems, for example, connected via a network. Memory media may store program instructions (e.g., representing a computer program) that can be executed by one or more processors.

[0040] Carrier media—memory media as described above, and physical transmission media such as buses, networks, and / or other physical transmission media that transmit signals such as electrical signals, electromagnetic signals, or digital signals.

[0041] Programmable hardware elements—including a variety of hardware devices comprising multiple programmable functional blocks connected via programmable interconnects. Examples include FPGAs (Field-Programmable Gate Arrays), PLDs (Programmable Logic Devices), FPOAs (Field-Programmable Object Arrays), and CPLDs (Complex PLDs). Programmable functional blocks can vary from fine-grained (combinatorial logic units or lookup tables) to coarse-grained (arithmetic logic units or processor cores). Programmable hardware elements may also be referred to as “configurable logic units.”

[0042] Computer system—any of all types of computing or processing systems, including personal computer systems (PCs), mainframe computer systems, workstations, network appliances, internet-connected appliances, personal digital assistants (PDAs), personal communication devices, smartphones, television systems, grid computing systems, or other devices or combinations thereof. In general, the term "computer system" can be broadly defined to encompass any device (or combination of devices) having at least one processor that executes instructions from a memory medium.

[0043] A user device (UE) (or “UE equipment”) is any of a variety of computer system devices that are mobile or portable and perform wireless communications. Examples of UE equipment include mobile phones or smartphones (such as iPhones). TM Based on AndroidTM Telephones), wearable devices (e.g., smartwatches, 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. Generally, the term "UE" or "UE device" can be broadly defined to include any electronic, computing, and / or telecommunications equipment (or combination of equipment) that is easily transportable by the user and capable of wireless communication.

[0044] Base station—The term “base station” has the full range of its common meaning and includes at least a wireless communication station that is installed in a fixed location and is used for communication 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, the entire processor core, individual processors, programmable hardware devices (such as field-programmable gate arrays (FPGAs)), and / or a large portion of a system comprising multiple processors.

[0046] Automatic—refers to actions or operations performed by a computer system (e.g., software executed by the computer system) or device (e.g., circuits, programmable hardware components, ASICs, etc.) without requiring direct user input to specify or perform the actions or operations. Therefore, the term "automatic" contrasts with actions performed or specified manually by the user, where the user provides input to directly perform the action. An automatic process can be initiated by user-provided input, but the subsequent actions performed "automatically" are not specified by the user; that is, they are not performed "manually," where the user specifies each action to be performed. For example, a user filling out a form by selecting each field and providing input specifying information (e.g., by typing information, selecting a checkbox, selecting a radio component, etc.) is considered manually filling out the form, even though the computer system must update the form in response to the user's actions. The form can be automatically filled out by a computer system (e.g., software executed on the computer system) which analyzes the fields of the form and fills it out without any user input specifying answers for the fields. As indicated above, the user can invoke the automatic filling of the form but does not participate in the actual filling of the form (e.g., the user does not manually specify answers for the fields, but they are completed automatically). This manual provides various examples of operations that are automatically performed in response to actions taken by the 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 system described is merely an example of some possible systems, and the implementation can be carried out in any of the various systems as needed.

[0049] Figure 1 An exemplary wireless communication system includes a base station 102A that communicates with one or more user equipment (UE) devices 106A, 106B, etc., to 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, in addition to base station 102A, base station 102B also (e.g., simultaneously or concurrently) communicates with UE devices 106A, 106B, etc., to 106N via a transmission medium.

[0050] Base stations 102A and 102B may be transceiver base stations (BTS) or cell sites, and may include hardware for enabling wireless communication with user equipment 106A to 106N. Each base station 102 may also be configured to communicate with 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 the 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, the Public Switched Telephone Network (PSTN), or any other network. Therefore, base station 102A may facilitate communication between user equipment and / or between user equipment and network 100A; Figure 2 In the exemplary system, base station 102B can also facilitate communication between user equipment and / or between user equipment and network 100B.

[0051] Base stations 102A and 102B can be configured to communicate with user equipment using a transmission medium of any of the various radio access technologies (RATs), also known as wireless communication technologies or telecommunications standards, such as GSM, UMTS (WCDMA), LTE, LTE-A Advanced, 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., a cellular service provider or "operator") or different network operators. Furthermore, the two networks may operate independently of each other (e.g., if they operate according to different cellular communication standards), or they may operate in a manner that is either partially coupled or tightly coupled.

[0053] It should also be noted that, although in Figure 2 The exemplary network configuration shown illustrates the use of 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 can 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) can be coupled to a core network that also supports different cellular communication technologies. Various other network deployment scenarios are also possible.

[0054] As another possibility, base stations 102A and 102B may also operate using 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 a single cellular service provider independently of base station 102B and core network 100B, which may be operated by different (e.g., competing) cellular service providers. Therefore, in this scenario, despite using similar and potentially compatible cellular communication technologies, UE devices 106A-106N can communicate independently with base stations 102A-102B, possibly by utilizing separate user identities to communicate with different operator networks.

[0055] UE 106 is capable of communicating using multiple wireless communication standards. For example, UE 106 can be configured to communicate using any one or two of the following 3GPP cellular communication standards: such as LTE and / or 3GPP2 cellular communication standards: such as those in the CDMA2000 series. As another example, UE 106 can be configured to communicate using two or more different 3GPP cellular communication standards: such as 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, operating under the same or different cellular communication standards, and other base stations may therefore be provided as one or more cell networks that can provide continuous or near-continuous overlapping services to UEs 106A-106N and similar devices over a wide geographical area via one or more cellular communication standards.

[0057] UE 106 can also be configured, or alternatively 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 broadcasting standards (e.g., ATSC-M / H or DVB-H). Other combinations of wireless communication standards (including more than two wireless communication standards) are also possible.

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

[0059] The UE may include a processor configured to execute program instructions stored in memory. The UE can perform any of the method embodiments described herein by executing such stored instructions. Alternatively or additionally, the UE may include programmable hardware elements such as an FPGA (Field Programmable Gate Array) configured to perform any of the method embodiments described herein, or any portion thereof.

[0060] UE 106 can be configured to communicate using any of a number of wireless communication protocols. For example, UE 106 can 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 the receive chain and / or transmit chain among multiple wireless communication standards; for example, UE 106 may be configured to communicate using a single shared radio component using one or both of GSM or LTE. The shared radio component may include a single antenna, or may include multiple antennas for performing wireless communication (e.g., for MIMO).

[0062] Figure 3 —Exemplary cellular network

[0063] Figure 3 A simplified block diagram of an exemplary cellular network (wireless communication system) is shown, which can be used in particular to implement the various embodiments described herein. UE 106 can communicate with a cellular network, which may include a base station 102 (or eNodeB) and an evolved packet core (EPC) 101, as shown. UE 106 can communicate wirelessly with base station 102. Base station 102 can be coupled to a core network, which is shown as the 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 in this document as being performed by a cellular network (or NW) can be... Figure 3 One or more of the cellular network devices shown may be used to perform this function, such as base station 102, MME 322, HSS 324 or SGW 326 in EPC 100, and one or more of other possible 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 components for various purposes. For example, as shown, SOC 300 may include one or more processors 302 capable of executing program instructions for UE 106, and display circuitry 304 capable of performing graphics processing and providing display signals to display 345. The one or more processors 302 may also be coupled to a Memory Management Unit (MMU) 340, which may be configured to receive addresses from the one or more processors 302 and translate those addresses into locations in memory (e.g., memory 306, read-only memory (ROM) 350, NAND flash memory 310) and / or other circuitry or devices, such as display circuitry 304, radio components 330, connector I / F 320, and / or display 345. MMU 340 may be configured to perform memory protection and page table translation or setup. In some embodiments, MMU 340 may be included as part of one or more processors 302.

[0067] As shown in the figure, the SOC 300 can be coupled to various other circuits of the UE 106. For example, the UE 106 may include various types of memory (e.g., including flash memory 310), connector interface 320 (e.g., for coupling to computer systems, docking stations, charging stations, etc.), 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 communication with a base station and / or other devices. For example, the UE device 106 may use antenna 335 to perform wireless communication. As described above, the UE may be configured to communicate wirelessly using multiple wireless communication standards.

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

[0070] As shown in the figure, UE 106 may also include two or more User Identity Modules (SIMs) 360 and 362. One or both of SIMs 360 and 362 may be implemented as an embedded SIM (eSIM). 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 built into UE 106 and not removable. The eUICC may be programmable, allowing one or more eSIMs to be implemented on the eUICC. In other embodiments, the eSIM may be installed in the UE 106 software, for example, as program instructions stored on a storage medium (such as memory 306 or flash memory 310) that executes on a processor (such as processor 302) in UE 106. As an example, SIM 360 may be an application running on a Universal Integrated Circuit Card (UICC). Alternatively or otherwise, one or both of SIMs 360 and 362 may be implemented as a removable SIM card.

[0071] Each SIM 360 or 362 may include various types of information, including user- and / or device-specific personalized information (e.g., personalized information) and user- and / or device-independent information (e.g., public information). The personalized information may include user / unit-specific data, such as information identifying the user / unit to their operator's network, personalized authorization, and / or security information. Some or all of this personalized information may be used as the user identity of UE 106, for example, to identify UE 106 to the operator's network and obtain cellular services from the operator.

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

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

[0074] As another possibility, it is possible that some operators implementing LTE networks may desire to utilize multiple user identities within a single device. Specifically, in many cases, LTE (e.g., as a packet-switched communication technology) networks may (at least initially) be deployed for data communications (e.g., web browsing, email, and other networked applications), while voice communications may be carried out using (e.g., pre-existing) GSM and / or UMTS (e.g., which may include circuit-switched communication technologies) networks.

[0075] As further described below, the UE can implement various technologies that enable a specific SIM to perform pause and resume operations with the cellular network while reducing interruptions due to RRC state mismatches. Therefore, as further described herein, the UE 106 may include hardware and software components for implementing methods to improve pause / resume operations when switching between 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 a FPGA (Field Programmable Gate Array) or an ASIC (Application-Specific Integrated Circuit).

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

[0078] Figure 5 An exemplary block diagram of base station 102 is shown. It should be noted that... Figure 5The base station shown is merely one example of a possible base station. As illustrated, base station 102 may include one or more processors 404 capable of executing program instructions specific to base station 102. One or more processors 404 may also be coupled to a memory management unit (MMU) 440 (which may be configured to receive addresses from one or more processors 102 and translate those addresses into locations in memory (e.g., memory 460 and read-only memory (ROM) 450)) or other circuitry or devices.

[0079] Base station 102 may include at least one network port 470. Network port 470 may be configured to be coupled to a telephone network and provide access rights as described above. Figure 1 and Figure 2 The telephone network described herein includes multiple devices such as UE device 106.

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

[0081] Base station 102 may include at least one antenna 434 and possibly multiple antennas. At least one antenna 434 may be configured to function as a wireless transceiver and may be further configured to communicate with UE device 106 via radio component 430. Antenna 434 communicates with radio component 430 via communication link 432. Communication link 432 may be a receive link, a transmit link, or both. 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 base station 102 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). Alternatively, the processor 404 may be configured as a programmable hardware element such as a FPGA (Field Programmable Gate Array) or as an ASIC (Application-Specific Integrated Circuit) or a combination thereof.

[0083] like Figure 3 The cellular network equipment shown may have a slightly similar architecture to that described above, but typically does not include RF circuitry or antennas. Therefore, Figure 3 Each of the cellular network devices shown will typically have processing elements 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 contained within a network infrastructure to perform the methods. For example, as Figure 5 The gNB (or eNB) shown can directly receive instructions and messages from the UE and 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) can instruct the gNB (or eNB) to retain the UE's RRC context (i.e., connection state and / or established EPS bearer / PDU session and QoS details). The MME (or AMF) can start a timer, and if the timer expires before the suspended SIM resumes, the MME (or AMF) can instruct the Serving Gateway (S-GW) or User Plane Function (UPF) to release the UE's bearer / PDN context and instruct the eNB (or gNB) to release the UE context (i.e., forget the UE's C-RNTI and the rest of the state information and consider the UE to be idle). If the timer is running and the eNB (or gNB) receives an RRC recovery request from the UE, the eNB (or gNB) can confirm the existence of a C-RNTI and that the UE context can be recovered, and can forward the recovery request to the MME (or AMF). The MME (or AMF) can then notify the S-GW (or UPF) to modify the radio bearer (e.g., if they had previously informed the S-GW or UPF to freeze its context), stop the timer, and / or continue as if the UE were already connected. In other words, the combination of eNB-MME-SGW for LTE or gNB-AMF-UPF for 5G NR can be understood as interconnectedly involving the implementation of the embodiments described herein.

[0085] RRC Status Mismatch Avoidance—Problem Statement

[0086] As mentioned above, some UE devices may be able to include multiple User Identity Modules (SIMs). In some cases, these SIMs can be generic 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 communication across their multiple SIMs. Therefore, 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 activity on one SIM while performing another higher-priority activity on another SIM.

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

[0089] In a typical scenario, the first SIM (i.e., the data SIM) can participate in data communication and can operate in a connected mode with the network, for example, via a first Radio Resource Control (RRC) connection. For instance, the UE can actively perform data transmissions 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, the second SIM, i.e., the non-data SIM instance, can operate in idle mode.

[0090] The UE can then receive a page or user input indicating higher-priority communication to be conducted via the second SIM. For example, the UE can receive a mobile station received (MT) voice call from the network, the UE's user can initiate a mobile station calling (MO) voice call, or the UE can receive or send SMS (Short Message Service) messages or other circuit-switched (CS) communications.

[0091] In response to an indication of higher priority communication on the second SIM, the UE may perform a local suspension of the first RRC connection on the first SIM, that is, data communication on the first SIM may be suspended so that the UE's receiver can be used for higher priority communication on the second SIM.

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

[0093] Problems may occur if the network stops synchronizing with the UE regarding the status of the first RRC connection.

[0094] The restoration of the suspended first RRC connection can be performed based on a recovery sequence, such as via an RRC connection reconstruction request. In some cases, this recovery sequence may not be synchronized with the network, which may have developed incompatibility awareness with the first RRC connection after it was suspended. This lack of synchronization may affect throughput performance on the first SIM and may result in the loss of paging messages during the restoration and reconstruction process.

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

[0096] In a set of undesirable scenarios, even after the first SIM has transitioned to idle mode, the network may contain outdated information indicating that the first SIM is still in its original connected mode. Therefore, even if the UE is in idle mode, the network may attempt to page the UE on the first SIM, for example, for MT voice calls. This could lead to page faults and / or dropped calls or call failures. The network may also waste network resources, such as uplink and downlink resources, by allocating them to the first RRC connection (i.e., the first SIM on the UE), even if the first RRC connection is inactive and therefore unable or unprepared to receive these communications.

[0097] In the second undesirable scenario, sometime 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 re-establish the first RRC connection to perform or resume certain data communications, the network may be unable to receive its communications. The UE may then need to perform the process of establishing a new connection with the network to perform these communications. Therefore, the first SIM may not be able to quickly resume data communications via the first RRC connection. This can lead to data transmission failures and long delays (increased waiting time) for the UE's users.

[0098] Manufacturers and suppliers of multi-SIM and MUSIM devices have implemented various proprietary solutions to address some of the issues and related problems in these scenarios. However, these solutions must be validated and tuned for many different deployments globally to ensure adequate performance, which can require significant effort and resources. Therefore, improvements in this field are expected. Specifically, solutions defined by 3GPP will be needed to address these and other issues.

[0099] The UE instructs the network to pause / update operations for RRC state synchronization.

[0100] In some implementations, in scenarios such as those described above, where the first SIM is paused to allow the second SIM to perform a higher-priority task, the paused first SIM (or the software stack executing and using the first SIM) can gracefully indicate to the NW using a “lightweight” mechanism (relatively small signaling volume) that it is paused for another high-priority activity on another SIM instance.

[0101] Alternatively, during the recovery period when the second SIM has completed a higher priority task and withdrawn the use of the radio components, and the first SIM has restored its connection to resume its data transmission, the first SIM that requested recovery may hereby notify the cellular network of the time following the local suspension due to high priority activity on other SIM instances.

[0102] One motivation or goal of implementing 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 respective cellular networks.

[0103] In one implementation, the first SIM, which is about to be suspended, may request a temporary transition to an RRC inactive state, and the SIM's connection state or context is stored and maintained on the network side, while another high-priority activity is completed on the first SIM. Storing and maintaining the first SIM's connection state or context on the network side allows the network to quickly restore the first SIM's connection state when the second SIM completes its higher-priority task.

[0104] For example, when storing UE context, we can indicate in this document that the NW may store one or more of the following: UE identifiers such as UE ID (i.e., C-RNTI); the UE's state (e.g., connected); the duration of SIM1 suspension; and / or the Packet Data Network (PDN), Evolved Packet System (LTE) bearer, and / or the Packet Data Unit (PDU) session established while the UE was in connected mode, along with its Quality of Service (QoS) and / or QoS Flow Identifier (QFI). Using this stored information, when the SIM1 connection is restored, the NW can allocate physical and transport channel resources to the UE for PDN / EPS bearer / PDU sessions and previously configured QoS / QFI, and can resume data transmission.

[0105] Since the network is now aware of the SIM's paused status, the transmission or communication of information about SIM pause / resumption between the UE and the cellular network can result in fewer paging failures on the paused SIM. Furthermore, these methods provide faster and more efficient resumption of paused SIMs, reducing the chance of the network refusing resumption due to potential RRC state mismatches.

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

[0107] Figure 6 —The UE provides the network with an indication of RRC state synchronization (without timeout recovery).

[0108] Figure 6To illustrate the message sequence diagram for the method used by the UE, which has two SIMs to coordinate with the network (or provide indication to the network) regarding its SIM pause / resume operations, thereby improving RRC state synchronization.

[0109] Figure 6 The message sequence diagram illustrates various message passing 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 the 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 executes with the first SIM (SIM 1) to perform cellular communication using the first SIM, and the UE maintains a second communication software stack that executes with the second SIM (SIM 1) to perform cellular communication using the second SIM.

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

[0111] At point 614, a high-priority activity is triggered on UE stack 2, where such a high-priority activity requires pausing the current activity on UE stack 1. For example, UE stack 1 can participate in an RRC connection mode for data transmission with NW 1, and a voice call can be activated on UE stack 2. In other words, a voice call can be initiated (or received) by the UE, where the voice call is processed by UE stack 2. For example, a mobile station calling (MO) call can be initiated or sent by the UE's user, where UE stack 2 is used to process the MO call. Alternatively, a mobile station called (MT) call can be received by the UE, where UE stack 2 is used to process the MT call.

[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 pause the operation.

[0113] In response to a notification from UE stack 2, at point 618, UE stack 1 can then forward an RRC connection suspension request to the cellular network (NW 1) to which UE stack 1 is connected. The RRC connection suspension request may include information specifying the reason for the suspension request. More specifically, the RRC connection suspension request may include information specifying that the suspension 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 in the figure, receiving an RRC connection suspension request from UE stack 1 allows NW 1 to transmit an RRC connection suspension message back to UE stack 1 at position 620. The RRC connection suspension message may include a code or instruction specifying that UE stack 1 should transition from "connected" mode to "inactive" mode. This 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 suspension message indicates that UE stack 1 is entering an inactive state. In other words, the "suspend_state" code is used to indicate the new RRC state of UE stack 1. In other embodiments, the RRC connection suspension message may maintain the RRC connection in "connected" mode, but with an extended DRX cycle configuration. For example, as such... Figure 6 The alternative to switching UE stack 1 from "connected" mode to "inactive" mode shown is that the RRC connection pause message at 620 can extend the DRX cycle duration and maintain the "connected" mode of UE stack 1.

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

[0116] In response to UE stack 1 receiving an RRC connection pause message from NW 1, UE stack 1 pauses at 622, and therefore UE stack 1 can enter RRC inactivity mode at 624 to promote or enable higher priority activity on UE stack 2. Receiving an RRC connection pause message can also trigger the start of a pause timer on the UE.

[0117] In some implementations, NW 1 may also include a similar pause timer, and the transmission of an RRC connection pause message may cause NW 1 to start its own pause timer. Therefore, UE stack 1 (UE) and NW 1 may start their own corresponding pause timers to determine the time during which the RRC connection between UE stack 1 and NW 1 remains inactive before timeout and transition to RRC idle mode.

[0118] As shown in the figure, triggering a high-priority activity on UE stack 2 causes UE stack 2 to enter RRC connection mode at position 626. Then, UE stack 2 can execute a higher-priority activity, such as a voice call, at position 628.

[0119] exist Figure 6 In an exemplary implementation, a high-priority activity (voice call) on UE stack 2 completes at 628 before the pause timer expires. Upon completion of the high-priority activity on UE stack 2, UE stack 2 enters RRC idle mode at 630. UE stack 2 can then notify UE stack 1 at 632 that the high-priority activity on UE stack 2 has completed and that UE stack 2 is now in idle mode. In response, UE stack 1 can send an RRC connection restoration request to NW 1 at 634. NW 1 receives the RRC connection restoration request and, in response, sends an RRC connection reconfiguration message back to UE stack 1 at 636. UE stack 1 receives the RRC connection reconfiguration message and, in response, enters RRC connection mode. UE stack 1 then sends an RRC connection reconfiguration complete message back to NW 1 at 638, thereby entering RRC connection mode.

[0120] Figure 7 —Message Flowchart— The UE provides the network with an indication of RRC state synchronization (timeout recovery).

[0121] Figure 7 To illustrate the message sequence diagram for the method used by the UE, which has two SIMs to coordinate with the network (or provide indication to the network) regarding its SIM pause / resumption operations, thereby improving RRC state synchronization. Similar to... Figure 6 , Figure 7 The communication between UE stack 1702 and NW1 706 and between UE stack 2 704 and NW2 708 is described. Figure 7 and Figure 6 Similar, but different Figure 7 This illustrates a scenario where a timer expires before a high-priority activity is completed on UE stack 2. For example, each of steps 710-726 could be similar to... Figure 6 Proceed to steps 610-626.

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

[0123] Therefore, at 734, UE stack 1 can restore its connection with NW 1 by setting a new RRC connection. At 738, UE stack 1 sends an RRC connection restoration request to NW 1. At 740, NW 1 responds to UE stack 1 with an RRC connection establishment message, and UE stack 1 subsequently responds to NW 1 with an RRC connection establishment complete message at 742 to enter the RRC connection state with NW 1 at 744.

[0124] Figure 8 —Store network connection state context to keep RRC state synchronized

[0125] Figure 8 A message sequence diagram illustrating an alternative implementation is shown. Similar to... Figure 6 and Figure 7 , Figure 8 The message sequence diagram illustrates various message passes between the first communication software stack operating with the first SIM (SIM1) 802, the second communication software stack operating with the second SIM (SIM2) 804, and the cellular network (NW(SIM1)) 806 communicating with the first SIM. The first communication software stack operating with SIM1 can be in connected modes 808, 812, using the radio component (RF) of the UE 106 to perform data transmission with the NW(SIM1). As shown, the network NW(SIM1) is also in connected mode because it is communicating with the first communication software stack. Since the UE contains only a single radio component, SIM2 (the second communication software stack operating with SIM2) is in idle mode 810 when that radio component is being used by SIM1 (by the first communication software stack operating with SIM1). 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 station originating (MO) call is made or initiated by the UE's user, where SIM2 is used for the MO call. In response to the initiating MO call, SIM2 transmits a pause request to SIM1 at 816. In response to the pause request, SIM1 transmits an RRC pause request to the cellular network NW (SIM1) to which SIM1 is connected at 818. Figure 6 and Figure 7In the implementation scheme, receiving a pause request from SIM1 will cause NW (SIM1) to transmit a pause message back to SIM1, including an indication that SIM1 is transitioning to an inactive state and the timer duration value as described above. However, in Figure 8 In this implementation, instead of transmitting such a pause message back to the UE (SIM1), the network "freezes" the context (or connection state) of SIM1's current connection mode at point 822. In other words, the network NW (SIM1) stores the currently connected mode parameters / data related to the context or connection state of SIM1 in its memory and saves this stored context for later use (in resuming the connection mode). Furthermore, in response to receiving a pause request from SIM1, the network also suspends or blocks mobile station called (MT) calls and downlink data transmission to SIM1 at point 826. In other words, since NW (SIM1) knows that SIM1 will be unreachable for a period of time—that is, SIM1 will be unable to receive communication for a period of time (because it is requesting to be paused)—NW (SIM1) configures itself so that it will not send any downlink notifications for paging to SIM1 for a period of time, and further so that 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) can 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) can also enter a similar inactive or idle state.

[0127] In response to an 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 an idle state, SIM2 sends a recovery request message to SIM1 at 830. In response to receiving the recovery request from SIM1, SIM2 then sends an RRC recovery request to NW (SIM1) at 832. The RRC recovery request sent by SIM1 may contain 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 components. When network NW (SIM1) receives the RRC recovery request from SIM1, the network may respond in one of several different ways.

[0128] In one implementation, NW(SIM1) can restore the connection state or context of the previous connection mode at 834, i.e., the connection state that was previously "frozen" at step 822. This allows the previous connection mode to "resume" from where it stopped. NW(SIM1) can also resume (or abort) mobile station calls and downlink data transmission to SIM1. NW(SIM1) can also send an RRC recovery message to SIM1 at 838 to notify SIM1 that the previous connection mode has been restored. Therefore, in this implementation, both NW(SIM1) and SIM1 can return to the connection mode (connection state) at 840 and 842, and data transmission, MT calls, and paging are now operational, as they would normally be in the connection mode.

[0129] In another implementation, the situation might be that a considerable amount of time has passed during which the connection with SIM1 has been suspended. For example, an MO voice call performed by SIM2 might persist for more than a specified time period (e.g., determined by a timer used for this purpose). In this case, NW(SIM1) might have discarded the stored connection mode context when the timer expires (and then, of course, the network will no longer have the stored connection mode parameters to resume). In this scenario, when the specific time period has elapsed, NW(SIM1) can transition to an idle or inactive mode at 844, 846, and discard (no longer store) the previously stored connection mode context. NW(SIM1) can also send an RRC connection release message to SIM1 at 848. This message can also instruct SIM1 that it should also transition to an idle mode, which can be executed at 850. In this case, it might be necessary to re-establish a new connection between SIM1 and NW(SIM1) to enable data communication between them.

[0130] A key advantage of this method is that it ensures no discrepancies exist between the RRC states of the network and the UE. Furthermore, the network suspends paging and downlink data to the suspended SIM, thus preventing any issues related to attempts to communicate with the suspended device. Additionally, the network maintains complete control over the UE's RRC state, ensuring that both of the UE's SIMs remain synchronized with the network's RRC state; that is, the SIM's RRC state always matches the network's RRC state.

[0131] RRC status mismatch in 5G NR

[0132] Figure 9 This is a message sequence diagram illustrating potential problems in some existing specific implementations of DSDS devices. Similar to... Figures 6 to 8 , Figure 9The message sequence diagram illustrates the various message passing between the first communication software stack operating with the first SIM (SIM1 902), the second communication software stack operating with the second SIM (SIM2 904), and the cellular network (NW(SIM1) 906) communicating with the first SIM. However, Figure 9 This can be more specifically applied to 5G NR implementations utilizing RRC inactivity. The first communication software stack operating with SIM1 can be in connected mode 908, using the radio component (RF) of UE106 to perform data transmission with NW (SIM1). As shown, network NW (SIM1) is also in connected mode 912 because the network is communicating with the first communication software stack. Since the UE contains only a single radio component, SIM2 (the second communication software stack operating with SIM2) is in idle mode 910 when that radio component is being used by SIM1 (by the first communication software stack operating with SIM1). 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) can send an RRC connection release message to SIM1 to switch the connection between SIM1 and NW(SIM1) from connected mode to inactive mode. SIM1 and NW(SIM1) can then switch their mutual connection to inactive mode.

[0134] At 918, a voice call is initiated (or received) by SIM2. As shown in this example, a mobile station originating (MO) call is made or initiated by the UE's user, 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 pause 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 can access its cellular network (e.g., NW(SIM2), Figure 9 The connection is in an RRC state (not shown) and MO calls can be made with remote entities via NW (SIM2). MO calls can continue 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 a recovery request from SIM2 at 930, one of two alternative processes can occur, illustrated in the two large boxes corresponding to steps 932-942 and 944-952, respectively. In the first alternative, when SIM1 receives the recovery request from SIM2 at 930, the UE may assume it is in an inactive state with NW(SIM1) 934, while NW(SIM1) assumes the UE is in an idle state 936. In other words, there may be a mismatch between the UE's and NW(SIM1)'s understanding of the connection state between SIM1 and NW(SIM1). As an example, an MO call on SIM2 may persist long enough for NW(SIM1) to relinquish the context associated with its connection to SIM1 and transition the connection to an idle state, while the UE perceives the connection as inactive. For example, NW(SIM1) may have attempted to page SIM1 during the SIM2 call and may have timed out the connection with SIM1 due to a lack of timely response from SIM1. In these implementations, SIM1 may have UL data transmitted at 938 and may transmit an RRC recovery request with an Inactive Radio Network Temporary Identifier (I-RNTI) indicator to NW(SIM1) at 940 to resume UL data transmission. 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 the latency for UL transmission.

[0137] In the second alternative shown with reference to steps 944-952, an alternative mismatch may exist between the assumptions regarding the connection states of SIM1 and NW(SIM1). For example, the UE may assume that the connection between SIM1 and NW(SIM1) has been terminated and is idle at 946, while NW(SIM1) may keep 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 causing high latency during the establishment of the new RRC connection. The embodiments described below provide methods and apparatus for reducing the latency and battery consumption introduced in both alternatives.

[0138] Use pause timers to avoid RRC state mismatch

[0139] Figure 10 To illustrate message sequence diagrams according to some embodiments, this message sequence diagram illustrates a method and apparatus for enhancing the operation of a DSDS device using a pause timer. More specifically, Figure 10 It is a message sequence diagram, which solves the problem of... Figure 9 The message sequence diagram shown includes some constraints and wait times. Similar to... Figures 6 to 9 , Figure 10 The message sequence diagram illustrates the various message passing between the first communication software stack operating with the first SIM (SIM1 1002), the second communication software stack operating with the second SIM (SIM2 1004), and the cellular network (NW(SIM1) 1006) communicating with the first SIM. However, Figure 10 This can be more specifically applied to 5G NR implementations utilizing the RRC inactive state. The first communication software stack operating with SIM1 can be in connected mode 1008, using the radio component (RF) of UE 106 to perform data transmission with NW (SIM1). As shown, network NW (SIM1) is also in connected mode 1012 because the network is communicating with the first communication software stack. Since the UE contains only a single radio component, SIM2 (the second communication software stack operating with SIM2) is in idle mode 1010 when this radio component is being used by SIM1 (by the first communication software stack operating with SIM1). 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] Figure 10 Steps 1008-1022 can be combined with Figure 9 Steps 908-922 are performed similarly, thereby transitioning the connection between SIM1 and NW (SIM1) from a connected state to an inactive state. Alternatively, in some implementations, the network may not support an inactive state, and the connection between SIM1 and NW (SIM1) can be transitioned to an idle state. Figure 10 (Not shown in the image). Alternatively, in other embodiments, the RRC connection release message can maintain the RRC connection in connected mode, but with an extended DRX cycle configuration. For example, as... Figure 10 The alternative shown is to switch SIM1 from connected mode to inactive mode. The RRC connection release message at 1014 extends the DRX cycle duration and maintains SIM1 in connected mode. Subsequently, SIM2 switches its connection with NW (SIM2) to an idle state to initiate an MO call, and SIM2 sends a pause request to SIM1 to gain access to the UE's shared RF chain. However, Figure 10 The subsequent steps deviated Figure 9 The steps are shown.

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

[0142] Subsequently, one of two alternative processes can be implemented, depending on whether the MO call on SIM2 has ended when the pause timer expires, as per steps 1030-1036 and 1038-1056 respectively. Figure 10 The two large boxes are described.

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

[0144] In the second alternative, the SIM2 call may terminate at 1038, and the connection between SIM2 and NW (SIM2) may enter an idle state at 1040 before the pause timer expires. In these implementations, SIM2 may transmit a recovery request to SIM1 at 1044, and SIM1 may assume that the connection between SIM1 and NW (SIM1) remains inactive at 1046. Therefore, at 1050, SIM1 may transmit an RRC recovery request to 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 NW (SIM1). For example, if the UE has remaining UL data to transmit via SIM1, it may request that the SIM1 / NW (SIM1) connection be switched to a connected state to transmit the UL data. If the UE has no other data to transmit via SIM1, the nextStatePreference indicator may indicate a preference for an inactive or idle state, depending on the various implementations. Because NW(SIM1) also maintains a pause timer, when it receives an RRC resume request from SIM1, it will keep its connection context with SIM1 in an inactive state. Therefore, depending on the nextStatePreference indicator and / or network-side considerations, NW(SIM1) can respond to SIM1 with an RRC resume or RRC connection release message. At 1054 and 1056, SIM1 and NW(SIM1) can continue operation according to the next state (e.g., connected mode, inactive mode, or idle mode).

[0145] Network coordination to avoid RRC state mismatch

[0146] Figure 11 To illustrate message sequence diagrams according to some implementation schemes, this message sequence diagram illustrates methods and apparatus for enhancing the operation of DSDS devices using network-side coordination. More specifically, Figure 11 This is a message sequence diagram for improving RRC connection state matching between the network and the UE using network-side coordination. Similar to... Figures 6 to 10 , Figure 11 The message sequence diagram illustrates the various message passing between the first communication software stack operating with the first SIM (SIM1 1102), the second communication software stack operating with the second SIM (SIM2 1104), the first cellular network (NW(SIM1) 1106) communicating with the first SIM, and the second cellular network (NW(SIM2) 1108) communicating with the second SIM. Figure 11This can be more specifically applied to 5G NR implementations utilizing RRC inactivity. The first communication software stack operating with SIM1 can be in connected mode 1110, using the radio component (RF) of UE 106 to perform data transmission with NW (SIM1). As shown, network NW (SIM1) is also in connected mode 1114 because the network is communicating with the first communication software stack. Since the UE contains only a single radio component, when this radio component is being used by SIM1 (by the first communication software stack operating with SIM1), SIM2 (the second communication software stack operating with SIM2) is in idle mode 1112, and NW (SIM2) can similarly be in 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] Figure 11 Steps 1110-1126 can be combined with Figure 9 Steps 908-922 and Figure 10 Steps 1008-1022 are performed similarly, thereby transitioning the connection between SIM1 and NW (SIM1) from a connected state to an inactive state. Alternatively, in some implementations, the network may not support an inactive state, and the connection between SIM1 and NW (SIM1) can be transitioned to an idle state. Figure 11 (Not shown in the image). Subsequently, SIM2 switches its connection with NW (SIM2) to an idle state to initiate an MO call, and SIM2 sends a pause request to SIM1 to gain access to the UE's shared RF chain. However, Figure 11 The subsequent steps deviated Figure 9 and Figure 10 The steps are shown.

[0148] Specifically, at 1128, SIM2 can initiate the RRC connection establishment process using NW(SIM2), and enter the RRC connection state at 1130. At 1132, NW(SIM2) can 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) can freeze its inactive mode connection with SIM1 and start a protection timer.

[0149] Subsequently, one of two alternative processes can be implemented, depending on whether the MO call on SIM2 has ended when the protection timer expires, as per steps 1136-1152 and 1154-1166 respectively. Figure 11 The two large boxes are described.

[0150] In the first alternative, the SIM2 call can terminate at 1138 and 1140 before the pause timer expires. At 1142, NW(SIM2) can send a recovery indication to NW(SIM1), indicating that NW(SIM1) can restore its connection with SIM1. In response, at 1144, NW(SIM1) can transmit a SIM1 status indicator to NW(SIM2), indicating the preferred RRC state for restoring its connection to SIM1. For example, in Figure 11 In the NW (SIM1), the SIM1 status indicator indicates the preference for the RRC inactive state, but the NW (SIM1) can also indicate the preference for the RRC connected state or the RRC idle state as needed.

[0151] At 1146, NW(SIM2) can transmit an RRC connection release message to SIM2 to release the connection between NW(SIM2) and SIM2, allowing SIM2 to enter idle mode. Importantly, NW(SIM2) can include a SIM1 preferred state indicator in the RRC connection release message, thereby informing SIM2 of the preferred RRC state of the connection between SIM1 and NW(SIM1). Advantageously, this can be achieved by sending a coordination message between SIM1 and NW(SIM1) to maintain state coordination between SIM1 and NW(SIM1) without consuming additional radio resources.

[0152] At 1148, SIM2 can send a recovery request to SIM1, indicating that SIM2 is withdrawing its RF chain access to the UE back to SIM1, and can include a preferred state indicator for SIM1 in the recovery request (e.g., SIM2 indicates to SIM1 that NW (SIM1) wants to...). Figure 11 In the inactive mode, the connection with SIM1 is restored, although the preferred status indicator for SIM1 can also indicate a preference for connected or idle modes as needed. Finally, at 1150 and 1152, according to the preferred status indicator, both SIM1 and NW (SIM1) can restore their connection without a pause. Therefore, communication via SIM1 to NW (SIM1) can be restored 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 pause 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) ended at 1156, NW(SIM2) may send a SIM1 recovery indicator to NW(SIM1) indicating that NW(SIM2) has ended its MO call with SIM2, allowing NW(SIM1) to restore its connection with SIM1. However, since NW(SIM1) has entered idle mode relative to its connection with SIM1 and no longer maintains the context of the connection, NW(SIM1) responds to NW(SIM2) with a preferred SIM1 status indicator indicating a preference for the RRC idle state. Similar to step 1146 above, at 1164, NW(SIM) sends an RRC connection release message to SIM2, including a SIM1 preference state indicator indicating that SIM1 prefers to enter an idle state. Finally, at 1142, SIM2 can send a recovery request to SIM1, indicating that SIM2 is withdrawing its RF chain access to the UE back to SIM1, and also includes a SIM1 preference state indicator for the idle state, so SIM1 enters the idle state at 1166. Therefore, both SIM1 and NW(SIM1) will transition to the idle state, thus avoiding a state mismatch regarding their connection without explicitly sending coordination messages between SIM1 and NW(SIM1).

[0154] Figure 12 —UE notification of network connection release

[0155] Figure 12 A message sequence diagram illustrating an alternative implementation is shown. Similar to... Figures 6 to 11 , Figure 12The message sequence diagram illustrates various message passing between the first communication software stack operating with the first SIM (SIM1) 1202, the second communication software stack operating with the second SIM (SIM2) 1204, the cellular network communicating with the first SIM (NW(SIM1)) 1206, and the cellular network communicating with the second SIM (NW(SIM2)) 1208. The first communication software stack operating with SIM1 can be in connected modes 1210, 1214, performing continuous data transmission 1216 with the NW(SIM1) using the radio component (RF) of the UE 106, while SIM2 is idle regarding its connection with the NW(SIM2). As shown, network NW(SIM1) is also in connected mode because it is communicating with the first communication software stack of SIM1. Since the UE contains only a single radio component, SIM2 (the second communication software stack operating with SIM2) is in idle mode 1210 when this radio component is being used by SIM1 (by the first communication software stack operating with SIM1). In the following discussion, the term "SIM1" is used to refer to the first communication software stack that operates in conjunction with SIM1, and similarly, "SIM2" is used to refer to the second communication software stack that operates in conjunction with SIM2.

[0156] In some implementations, when a non-data-preferred SIM (e.g., SIM1) terminates a voice call, it reverts the UE's RF chain back to the data-preferred SIM (e.g., SIM2), allowing SIM2 to resume data transmission that was suspended due to the SIM1 voice call. In this scenario, an RRC state mismatch may exist between SIM1 and the NW (SIM1), as the UE can typically perform a local release of the RRC connection only on SIM1, potentially leading to a mismatch with the NW (SIM1). Subsequently, if an MO user triggers a back-to-back voice call on SIM1, a second call may be missed due to the RRC state mismatch. To address these and other issues, Figure 12 A method is presented for the UE to notify the NW of connection release to avoid potential RRC state mismatches.

[0157] Although data transmission 1216 occurs between SIM1 and NW (SIM1), at 1218, SIM2 can initiate or receive a high-priority call. In response, at 1220, SIM2 can send a pause request to SIM1, granting SIM2 access to the UE's radio components. SIM2 can then establish a connection with NW (SIM2) at 1224 and 1226 for the high-priority call, and SIM1 can enter a pause state at 1222.

[0158] High-priority calls can terminate at 1228, and SIM2 can send a signaling connection release indication to NW(SIM2) at 1230 to notify the network that SIM2 has entered an idle state at 1232. Accordingly, in response to receiving the signaling connection release indication from SIM2, NW(SIM2) can also enter an idle state relative to its connected SIM2, so that SIM2 and NW(SIM2) are synchronized relative to their interconnected state.

[0159] At 1236, in response to entering the idle state, SIM2 may send a recovery request to SIM1, enabling SIM1 to restore its connection with NW (SIM1), and SIM1 may attempt to re-establish its RRC connection with NW (SIM1) at 1238.

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

[0161] At 1254, the incoming call of SIM2 can be notified to NW(SIM2) at 1254, and NW(SIM2) can page SIM2 in idle mode at 1256 for mobile station called (MT) calls. Therefore, SIM2 can establish an MT call at 1258.

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

[0163] The 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 higher priority cellular communication of a second software communication stack using a second SIM of the UE; and store the connection state of the RRC connection of the first software communication stack of the UE, wherein the stored connection state can be used to later restore the RRC connection.

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

[0165] In some implementations, cellular network devices may also be configured to stop transmitting downlink data to the UE in response to receiving an RRC connection pause request.

[0166] In other embodiments, the cellular network entity may include a radio component including one or more antennas for performing wireless communication; 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 user identity module (SIM) of a user equipment (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; suspend the first RRC connection and start a protection timer in response to receiving the first notification; receive a second notification from the second cellular network entity to restore the first RRC connection; transmit a preferred state indicator to the second cellular network entity indicating a preferred state for restoring the first RRC connection; and restore the first RRC connection with the first SIM of the UE according to the preferred state.

[0167] In some implementations, the cellular network is operable to receive a second indication after a timer expires, and preferably a status indicator indicates a preference for an RRC idle state.

[0168] In some implementations, the cellular network is operable to receive a second indication before the timer expires, and preferably a status indicator indicates a preference for an RRC inactive state or an RRC connected state.

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

[0170] As is widely recognized, the use of personally identifiable information should comply with privacy policies and practices that are generally accepted to meet or exceed industry or governmental requirements for protecting 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 authorized use should be clearly explained to users.

[0171] Embodiments of this 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 to store program instructions and / or data, wherein if the program instructions are executed by a computer system, the computer system performs a method, such as any method embodiment 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 implementations, a 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, and the processor is configured to read from the memory medium and execute the program instructions, wherein the executable program instructions are to implement any of the various method implementations described herein (or any combination of the method implementations described herein, or any subset of any method implementations described herein, or any combination of such subsets). A computer system may be implemented in any of a variety of forms. For example, a 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, many variations and modifications will become apparent to those skilled in the art once the disclosure is fully understood. This disclosure is intended to render the following claims as encompassing all such variations and modifications.

Claims

1. A wireless user equipment (UE), the UE comprising: A radio component, the radio component including one or more antennas for performing wireless communication; A processing element, which is operatively coupled to the radio component; and A first user identity module (SIM) and a second user identity module (SIM), wherein each of the first SIM and the second SIM is coupled to the radio component and configured to work with the radio component for wireless communication; The UE is configured as follows: In the first Radio Resource Control (RRC) state associated with the first SIM, cellular data communication with the first cellular network is performed using the first SIM and the first RRC connection; Receive a request to perform voice cellular communication using the second SIM and the second RRC connection in the RRC connection state associated with the second SIM; In response to the request to perform voice cellular communication using the second SIM and the second RRC connection, a request to suspend the first RRC connection is transmitted to the first cellular network; After transmitting the request to suspend the first RRC connection, a message is received from the first cellular network to suspend the first RRC connection and change the RRC status associated with the first SIM from the first RRC status to the second RRC status; as well as After performing the voice cellular communication using the second SIM, a message is sent to the second cellular network indicating an RRC release request associated with the second SIM, causing the UE to enter an RRC idle state relative to the second SIM at both the UE and the second cellular network.

2. The UE as described in claim 1, in, One or more of the first SIM and the second SIM is an embedded SIM, which uses embedded memory in the UE to store user information related to the first SIM and the second SIM.

3. The UE as described in claim 1, in, The request to use the second SIM to perform voice cellular communication is a paging received in the UE.

4. The UE as described in claim 3, in, The paging is received from a second cellular network used for the second SIM.

5. The UE as described in claim 1, in, The request to perform voice cellular communication originates from the user.

6. The UE as described in claim 1, in, The first RRC state is the RRC connection state; and The second RRC state is either an RRC idle state or an RRC inactive state.

7. The UE as claimed in claim 1, wherein, In order to perform the voice cellular communication, the UE is also configured to: transition the RRC state associated with the second SIM from the third RRC state to the fourth RRC state.

8. The UE as described in claim 7, in, The third RRC state is either the RRC idle state or the RRC inactive state.

9. The UE as described in claim 7, in, The fourth RRC state is the RRC connection state.

10. An apparatus for wireless communication, comprising: Processor, the processor being configured to cause the user equipment (UE) to: In the first Radio Resource Control (RRC) state associated with the first User Identity Module (SIM), the UE uses the first SIM and the first RRC connection to perform cellular data communication with the first cellular network; Receive a request to perform voice cellular communication using the second SIM and the second RRC connection in the RRC connection state associated with the second SIM of the UE; In response to the request to perform voice cellular communication using the second SIM and the second RRC connection, a request to suspend the first RRC connection is transmitted to the first cellular network; After transmitting the request to suspend the first RRC connection, a message is received from the first cellular network to suspend the first RRC connection and change the RRC status associated with the first SIM from the first RRC status to the second RRC status; as well as After performing the voice cellular communication using the second SIM, a message is sent to the second cellular network indicating an RRC release request associated with the second SIM, causing the UE to enter an RRC idle state relative to the second SIM at both the UE and the second cellular network.

11. The apparatus of claim 10, in, One or more of the first SIM and the second SIM is an embedded SIM, which uses embedded memory in the UE to store user information related to the first SIM and the second SIM.

12. The apparatus of claim 10, in, The request to use the second SIM to perform voice cellular communication is a paging received in the UE.

13. The apparatus as claimed in claim 12, in, The request to perform voice cellular communication originates from the user, and The paging is received from a second cellular network used for the second SIM.

14. The apparatus as claimed in claim 10, in, The first RRC state is the RRC connection state; and The second RRC state is either an RRC idle state or an RRC inactive state.

15. The apparatus of claim 10, wherein, In order to perform the voice cellular communication, the UE is also configured to: transition the RRC state associated with the second SIM from the third RRC state to the fourth RRC state. The third RRC state is either an RRC idle state or an RRC inactive state, and The fourth RRC state is the RRC connection state.

16. A method for operating a user equipment (UE), the method comprising: In the first Radio Resource Control (RRC) state associated with the first User Identity Module (SIM), the UE uses the first SIM and the first RRC connection to perform cellular data communication with the first cellular network; Receive a request to perform voice cellular communication using the second SIM and the second RRC connection in the RRC connection state associated with the second SIM of the UE; In response to the request to perform voice cellular communication using the second SIM and the second RRC connection, a request to suspend the first RRC connection is transmitted to the first cellular network; After transmitting the request to suspend the first RRC connection, a message is received from the first cellular network to suspend the first RRC connection and change the RRC status associated with the first SIM from the first RRC status to the second RRC status; as well as After performing the voice cellular communication using the second SIM, a message is sent to the second cellular network indicating an RRC release request associated with the second SIM, causing the UE to enter an RRC idle state relative to the second SIM at both the UE and the second cellular network.

17. The method of claim 16, in, One or more of the first SIM and the second SIM is an embedded SIM, which uses embedded memory in the UE to store user information related to the first SIM and the second SIM.

18. The method of claim 16, in, The first RRC state is the RRC connection state; and The second RRC state is either an RRC idle state or an RRC inactive state.

19. The method of claim 16, further comprising, for performing the voice cellular communication: Transition the RRC state associated with the second SIM from the third RRC state to the fourth RRC state. The third RRC state is either an RRC idle state or an RRC inactive state, and The fourth RRC state is the RRC connection state.

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