Managing downlink data during transitions between mobile networks

Abstract

A method in a user equipment (UE) having a first subscriber identity module for connecting to a first mobile network according to a first subscription and a second subscriber identity module for connecting to the first mobile network or a second mobile network according to a second subscription, the method comprising: determining, by processing hardware, a preference of how the first mobile network is to handle downlink data of the UE when the UE transitions from the first subscription to the second subscription (1102); and sending, by the processing hardware, an indication of the preference to the first mobile network to cause the first mobile network to handle the downlink data of the UE based at least in part on the preference (1104).

Description

Technical Field

[0001] This disclosure generally relates to wireless communications, and more specifically to the management of downlink data when a device switches from one mobile network to another. Background Technology

[0002] This background description is provided for the purpose of generally presenting the context of this disclosure. The work of the inventors currently designated, within the scope described in this background section and in aspects that may not conform to the prior art at the time of filing, is neither expressly nor impliedly acknowledged as prior art relative to this disclosure.

[0003] A device that an end user can use to communicate over a mobile network is typically called a "user equipment" (UE), and in some cases, it can communicate with multiple mobile networks. For example, a UE can include multiple identities specific to a particular network provider and can use these identities to connect to different mobile networks as corresponding subscribers.

[0004] For example, a UE can include: multiple Universal Subscriber Identity Modules (USIMs), which are software modules executed on a Universal Integrated Circuit Card (UICC) to provide security and authentication functions; or multiple Embedded SIMs (e-SIMs). In either case, the hardware and / or software components can provide multiple subscriber identities. Using one of these subscriber identities, the UE can connect to a mobile network, such as a Public Land Mobile Network (PLMN), and utilize some or all of the PLMN's services (e.g., voice calls, video calls, web browsing). The UE can then use another subscriber identity to connect to another PLMN or the same PLMN without the user turning off or resetting the UE, let alone replacing any part of the hardware, such as the physical card. Nevertheless, the UE may not be able to exchange user plane data with two PLMNs simultaneously.

[0005] Today, when a UE temporarily switches to another PLMN, it is unclear how the PLMN should handle the data addressed to the UE. For example, a UE equipped with corresponding USIMs for PLMN1 and PLMN2 may at some point receive paging requests from PLMN2 while simultaneously receiving data services from PLMN1. The UE may at least temporarily switch to PLMN2 while PLMN1 continues to receive downlink data to be transmitted to the UE via the radio interface. Summary of the Invention

[0006] Generally, the UE disclosed herein has multiple subscriber identities, which are used to communicate with multiple corresponding mobile networks or the same mobile network depending on the different subscriptions. The device determines its preferences regarding how the mobile network should handle downlink data addressed to the device when the device switches from the current subscription to another subscription.

[0007] An example embodiment of these technologies is a method in a UE having a first subscriber identity module for connecting to a first mobile network according to a first subscription and a second subscriber identity module for connecting to either the first or second mobile network according to a second subscription. The method can be implemented by processing hardware such as a processor executing instructions stored on a non-transitory computer-readable medium, and includes: determining a preference on how the first mobile network should process the UE's downlink data when the UE switches from a first subscription to a second subscription; and sending an indication of the preference to the first mobile network so that the first mobile network processes the UE's downlink data at least in part based on the preference.

[0008] Another example embodiment of these technologies is a UE that includes processing hardware and is configured to implement the methods described above.

[0009] Another example embodiment of these technologies is a method for processing downlink data of a UE in a first mobile network, the UE having a first subscriber identity module for connecting to the first mobile network according to a first subscription and a second subscriber identity module for connecting to either the first or second mobile network according to a second subscription. The method can be implemented by processing hardware such as a processor executing instructions stored on a non-transitory computer-readable medium, and includes: receiving from the UE an indication of how the UE prefers the first mobile network to process the UE's downlink data when the UE switches from a first subscription to a second subscription; detecting that the UE has switched from a first subscription to a second subscription; and processing the UE's downlink data at least in part based on the indication.

[0010] Another example embodiment of these technologies is a base station that includes processing hardware and is configured to implement one of the methods described above. Attached Figure Description

[0011] Figure 1 This is a block diagram of an example system in which the mobile network and / or user equipment (UE) are able to implement the techniques of this disclosure for managing downlink data addressed to the UE when the UE, which is equipped with multiple subscriber identity modules, is at least temporarily switched to another mobile network.

[0012] Figure 2 yes Figure 1 The UE can be based on its relationship with Figure 1 A block diagram of an example protocol stack for communication with base stations;

[0013] Figure 3 This is a message sequence diagram of a scenario where a UE requests the CN to buffer pending downlink data and newly arrived data when the UE is temporarily connected to different mobile networks;

[0014] Figure 4 This is a message sequence diagram of a scenario where a UE requests the CN to buffer pending downlink data but discards newly arrived data when the UE is temporarily connected to different mobile networks;

[0015] Figure 5 This is a message sequence diagram of a scenario where a UE requests a CN to discard pending downlink data but buffer newly arrived data when the UE is temporarily connected to different mobile networks;

[0016] Figure 6 This is a message sequence diagram of a scenario where a UE requests the CN to discard pending downlink data and newly arrived data when the UE is temporarily or permanently connected to different mobile networks;

[0017] Figure 7 This is a message sequence diagram of a scenario where, after a UE connects to another mobile network, the UE indicates to the mobile network its intention to return or not return to the mobile network.

[0018] Figure 8 This is a message sequence diagram of a scenario in which the UE notifies the mobile network of updates regarding the UE's preferences for processing downlink data;

[0019] Figure 9 This is a message sequence diagram of a scenario in which the UE uses Non-Access Stratum (NAS) messages to notify the CN of the UE's downlink data processing preferences;

[0020] Figure 10 This is a message sequence diagram of a scenario in which the UE notifies the CN of its downlink data processing preferences via Radio Resource Control (RRC) messages from the RAN;

[0021] Figure 11 This is a flowchart of an example method in a UE for configuring the mobile network to process downlink data when the UE switches to another mobile network, based on the UE's preferences; and

[0022] Figure 12 This is a flowchart of an example method for processing downlink data of a UE when it switches to another mobile network. Detailed Implementation

[0023] Figure 1An example wireless communication system 100 is illustrated, wherein UE 102 is a multi-USIM device implementing the techniques of this disclosure. UE 102 communicates with base station 104, which operates in radio access network (RAN) 105 coupled to core network (CN) 120A, and UE 102 communicates with base station 106, which operates in RAN 107 coupled to CN 120B. RAN 105 and core network 120A are associated with PLMN1, and RAN 107 and CN 120B are associated with PLMN2.

[0024] As discussed in more detail below, UE 102 determines its downlink data preferences when UE 102 has at least temporarily switched to another mobile network such as PLMN2 or switched to another subscription on PLMN1, such as PLMN2. l The mobile network can receive the downlink data from UE 102. For example, preferences can enable the mobile network to buffer pending downlink data, discard pending downlink data, buffer newly arrived downlink data, and / or discard newly arrived downlink data. UE 102 can determine the preference and indicate the preference to the mobile network, which can then process the UE's downlink data according to the preference, unless the preference conflicts with one or more policies of the mobile network.

[0025] For clarity, the following examples primarily involve PLMN. l UE conversion between subscriptions on PLMN1 and subscriptions on PLMN2. However, unless otherwise stated, these techniques also apply to UE conversion between subscriptions on the same PLMN.

[0026] UE 102 can determine this preference dynamically and / or statically. For example, the UE can determine its preference when it receives a paging request from a new (second) mobile network, and base this determination on the type of data that UE 102 is currently receiving from the first mobile network and / or how long UE 102 expects to communicate with the second mobile network (which in turn may depend on which service the UE expects to use with the second mobile network). Alternatively, UE 102 can store permanent settings, which may be, for example, user-specific or manufacturer-specific.

[0027] Furthermore, UE 102 can specify its preferences at various granular levels, such as for all downlink data, for downlink data associated with a specific PDU session or PDN connection, or for downlink data associated with a specific QoS flow or EPS bearer. UE 102 can provide references to the mobile network using Non-Access Stratum (NAS) messaging or Radio Resource Control (RRC) messaging, depending on the implementation and / or scenario.

[0028] like Figure 1 As illustrated, base station 104 supports cell 112, and base station 106 supports cell 114. Cells 112 and 114 can partially overlap, so UE 102 can communicate with PLMN1 in cell 112 while simultaneously receiving paging requests, for example, from PLMN2 in cell 114. Typically, the wireless communication system 100 can include any suitable number of base stations supporting NR cells and / or EUTRA cells. More specifically, CN 120A and 120B can be connected to any suitable number of base stations supporting cells.

[0029] The CN 120A can be either the Evolution Packet Core (EPC) 130 or the 5th Generation Core (5GC) 140, both of which are... Figure 1 The CN 120B can similarly be implemented as an EPC, 5GC, or another suitable core network. Each of base stations 104 and 106 can be an eNB supporting an S1 interface for communication with the corresponding EPC, an ng-eNB supporting an NG interface for communication with the corresponding 5GC, or a gNB supporting both an NR radio interface and an NG interface for communication with the 5GC. Base station 104 can be an EUTRA-NR DC (EN-DC) gNB (en-gNB) with an S1 interface to EPC 130, an en-gNB connected to EPC 130, a gNB supporting both an NR radio interface and an NG interface to 5GC 140, or an ng-eNB supporting both an EUTRA radio interface and an NG interface to 5GC 140.

[0030] Among other components, EPC 130 may include a Mobility Management Entity (MME) 131, a Serving Gateway (SGW) 132, and a Packet Data Network Gateway (PGW) 133. MME 131 is typically configured to manage authentication, registration, paging, and other related functions. SGW 132 is typically configured to transmit user plane packets related to audio calls, video calls, Internet traffic, etc. PGW 133 is typically configured to provide connectivity from UE 102 to one or more external packet data networks (e.g., Internet network 118 and / or Internet Protocol (IP) Multimedia Subsystem (IMS) network).

[0031] 5GC 140 includes Mobility Management Function (AMF) 141, Session Management Function (SMF) 142, and User Plane Function (UPF) 143. AMF 141 is typically configured to manage authentication, registration, paging, and other related functions; SMF 142 is typically configured to manage Protocol Data Unit (PDU) sessions, and UPF 143 is typically configured to transmit user plane data packets related to audio calls, video calls, Internet traffic, etc.

[0032] Each of components 131-133 and 141-143 can be implemented in processing hardware that can include one or more general-purpose processors such as a CPU and non-transitory computer-readable memory that stores machine-readable instructions executable on a general-purpose processor and / or a dedicated processing unit.

[0033] Although the examples below specifically involve particular CN types (EPC, 5GC) and particular radio access technology (RAT) types (5G NR and EUTRA), in general, the technologies disclosed herein can also be applied to other suitable radio access and / or core network technologies, such as sixth-generation (6G) radio access and / or 6G core networks or 5G NR-6G DC.

[0034] Continue to refer to Figure 1 CN 120A can implement downlink (DL) data controller 150. For example, when CN 120A is implemented as EPC, DL data controller 150 can be implemented in SGW 132, or when CN 120A is implemented as 5GC, DL data controller 150 can be implemented in UPF 143. As another example, DL data controller 150 can be implemented partly in SMF 142 and partly in UPF 143. Furthermore, DL data controller 150 is partially implemented in base station 104 in some embodiments. DL controller 150 can more generally be implemented in one or more components of CN 120A and / or RAN 105.

[0035] During operation, the DL data controller 150 determines when the UE 102 temporarily or permanently leaves the PLMN. l In some implementations, UE 102 also determines a relevant policy of CN 120A relative to its preference for processing downlink data, and applies this preference and / or policy in relevant scenarios. See below for reference. Figure 3-10 Let's discuss some scenarios.

[0036] Still referencing Figure 1UE 102 is equipped with processing hardware 160, which may include: one or more general-purpose processors, such as a CPU; and non-transitory computer-readable memory storing machine-readable instructions executable on one or more general-purpose processors and / or dedicated processing units. UE 102 also includes USIM1 (component 161) and USIM2 (component 162) for communicating with PLMN1 and PLMN2 respectively. However, in some embodiments, UE 102 uses USIM1 and USIM2 to communicate with the same mobile network (e.g., PLMN1 or PLMN2) depending on different subscriber identities. Either USIM may be associated with a card (typically referred to as a "SIM card") that is part of the UICC, or may be embedded as an eSIM.

[0037] The processing hardware 160 in the example implementation includes a DL data controller 162, which is configured to support the techniques of this disclosure for managing downlink data at PLMN1. In operation, the DL data controller 162 is capable of determining permanent settings 164 (e.g., manufacturer settings, operator settings, user settings) stored in the memory of UE 102 and / or related to applications and services 166 (APP1, APP2, ... APP...). N Related dynamic conditions, applications and services 166 such as voice and video call services, SMS services, web browsing applications, email applications, game applications or music streaming applications.

[0038] Next, Figure 2 The radio protocol stack is illustrated in a simplified manner, according to which UE 102 can communicate with an eNB / ng-eNB or a gNB. Each of base stations 104 and 106 can be an eNB / ng-eNB or a gNB.

[0039] EUTRA's physical layer (PHY) 202A provides a transport channel to EUTRA Media Access Control (MAC) sublayer 204A, which in turn provides a logical channel to EUTRA Radio Link Control (RLC) sublayer 206A. The EUTRA RLC sublayer then provides an RLC channel to EUTRA PDCP sublayer 208, and in some cases, to NR PDCP sublayer 210. Similarly, NR's PHY 202B provides a transport channel to NR MAC sublayer 204B, which in turn provides a logical channel to NR RLC sublayer 206B, and NR RLC sublayer 206B then provides an RLC channel to NR PDCP sublayer 210. In some implementations, UE 102 supports both EUTRA and NR stacks to support handover between EUTRA and NR base stations and / or DCs via EUTRA and NR interfaces. Furthermore, as... Figure 2 As shown in Figure A, UE 102 is able to support the layering of NR PDCP 210 on EUTRA RLC 206A.

[0040] EUTRA PDCP sublayer 208 and NR PDCP sublayer 210 (e.g., receiving packets that can be called Service Data Units (SDUs) from Internet Protocol (IP) layers that are directly or indirectly layered on PDCP layers 208 or 210) and outputting packets that can be called Protocol Data Units (PDUs) (e.g., to RLC layers 206A or 206B). Except where the difference between SDU and PDU is relevant, for simplicity, this disclosure refers to both SDU and PDU as “packets”.

[0041] For example, on the control plane, EUTRA PDCP sublayer 208 and NR PDCP sublayer 210 provide SRBs to exchange Radio Resource Control (RRC) messages. On the user plane, EUTRA PDCP sublayer 208 and NR PDCP sublayer 210 provide DRBs to support data exchange.

[0042] When UE 102 operates in EUTRA / NR DC (EN-DC), where BS 104 operates as MeNB and BS 106 operates as SgNB, the network can provide UE 102 with either an MN-terminated bearer using EUTRA PDCP 208 or an MN-terminated bearer using NRPDCP 210. In various scenarios, the network can also provide UE 102 with an SN-terminated bearer using only NR PDCP 210. The MN-terminated bearer can be an MCG bearer or a split bearer. The SN-terminated bearer can be an SCG bearer or a split bearer. The MN-terminated bearer can be an SRB (e.g., SRB1 or SRB2) or a DRB. The SN-terminated bearer can be an SRB (e.g., SRB) or a DRB.

[0043] Next, refer to Figure 3-10 This paper discusses several scenarios in which the mobile network processes downlink data at least in part based on the UE's preferences. Although Figure 3-8 The signaling diagram illustrates two core networks, 120A and 120B, and assumes different PLMNs, but the techniques shown are also applied to UE switching between different subscriptions on the same PLMN, unless otherwise stated.

[0044] First refer to Figure 3 In scenario 300, UE 102 may optionally provide CN 120A with an indication of default preferences for processing downlink data. The default preferences can be applied where UE 102 temporarily (e.g., less than T) MAX (time amount) or permanent (e.g., greater than T) MAX The preference applies to scenarios where UE 102 leaves PLMN1 within a time interval T. This preference can be applied to downlink data that is already pending when UE 102 notifies PLMN1 of its departure, and to data that has already been notified of its departure by UE 102 but is still pending within a time interval T. MAX Downlink data arriving before the expiration date, or both. MAX The value can be, for example, 100 milliseconds, 300 milliseconds, 500 milliseconds, 2 seconds, or any other value, and can depend on, for example, the PLMN, the manufacturer of the UE 102, the application server communicating with the UE, or the relevant 3GPP standard.

[0045] In some cases, CN 120A uses NAS messages to specify T to UE 102. MAX The value. If UE 102 fails to meet the predetermined time period T MAX If the data is returned to CN 120A, then CN 120 clears the stored downlink data, as will be described later.

[0046] For example, the default preference can be a tuple {buffer, buffer}, {buffer, drop}, {drop, buffer}, or {drop, drop}, which specifies the default action for pending downlink data and newly arrived data, respectively. In some implementations, the default preference for pending and / or newly arrived data can be set to "don't care" to effectively allow CN 120A to apply its default policy. As another example, the default preference can be "return," indicating that UE 102 intends to return to PLMN1 to resume ongoing data transmission (e.g., a PDU session) interrupted by events such as a paging request from PLMN2, or the default preference can be "don't return," indicating that UE 102 does not intend or expect to return to PLMN1 after switching to PLMN2. In this case, CN 120A can apply a default policy for this preference, such as {buffer, buffer} for "return" or {drop, drop} for "don't return."

[0047] For example, in some implementations, UE 102 can further parameterize the default preference by specifying the maximum amount of data to be buffered. Therefore, UE 102 can format the default preference as {buffer X, buffer Y} to request PLMN1 to buffer up to X bytes of pending downlink data and up to Y bytes of newly arrived downlink data. Similarly, CN 120A can apply strategies to limit the amount of buffered pending downlink data and / or newly arrived downlink data as appropriate.

[0048] In some implementations, CN 120A is configured to receive from UE 102 or CN 120B an indication that CN 120B is paging a service related to UE 102 while UE 102 is communicating with CN 120A. CN 120A can determine, for example, whether UE 102 has received a paging request for an SMS delivery or a paging request for a voice call from CN 120B. When UE 102 switches from one subscription to another on the same PLMN, CN 120A can also identify the service involved in the paging request associated with the new subscription. In these cases, the default preference can be service-specific, for example, {{SMS: buffered, buffered}, {MMS call: buffered, dropped}, {voice call: dropped, dropped}, ...}. Alternatively, UE 102 can specify a preference based on the intent associated with a specific service: {{SMS: return}, {MMS call: return}, {voice call: no return}, ...}.

[0049] Furthermore, the default preferences in various implementations specify how UE 102 expects CN 120A to process downlink data at various granular levels. For example, UE 102 can specify preferences for specific Quality of Service (QoS) or EPS bearers.

[0050] In some implementations, UE 102 provides a 302 default notification to MME 131 or AMF 141 during registration using the Mobility Management (MM) protocol. UE 102 can include an Information Element (IE) in one of the uplink messages. In another implementation, UE 102 provides a 302 default notification to CN120A only when UE 102 expects to establish a PDN session or PDU session using the Session Management (SM) protocol. In some implementations, UE 102 can also provide a 302 default notification in response to user changes to certain settings. In those implementations or scenarios where UE 102 does not provide default preferences at all, CN 120A can apply a default policy. Generally, UE 102 can provide a default notification to CN 120A zero, one, or more times while active in PLMN1.

[0051] Continue to refer to Figure 3 UE 102 is capable of receiving 310 downlink data packets in a communication session with CN 120A. For example, UE 102 is capable of receiving data packets from music playback application 166 that establishes a specific PDU session for streaming music.

[0052] While UE 102 continues to receive downlink data (310), CN 120B sends a paging request to UE 102. In some implementations, the paging information includes a service indicator to indicate whether CN 120B is paging UE 102 in conjunction with an SMS delivery, MMS delivery, mobile-terminated voice call, mobile-terminated video call, etc. In other implementations, UE 102 cannot determine the service type upon receiving the paging information (310). In some of these cases, UE 102 can later determine the service type based on subsequent messaging with CN 120B. Furthermore, in some cases, PLMN2 can directly provide PLMN1 with an indication of the service for the paging request.

[0053] In response to receiving paging request 312, UE 102 determines whether UE 102 intends (or plans) to return to CN 120A after completing the service involved in the paging request from CN120B. As discussed below, UE 102 may not always correctly determine its intent, and in some cases may re-evaluate its intent at a later time.

[0054] exist Figure 3 In this scenario, UE 102 determines that it intends to return to CN 120A after receiving information related to the paging request. For example, UE 102 can determine that the paging request is related to SMS or MMS delivery, and that receiving downlink data from CN 120B can be completed within a predetermined time period T.MAX The process is completed within the specified timeframe. UE 102 sends a 320 downlink data processing preference indication to CN 120A to specify preferences for buffering pending downlink data and newly arriving pending downlink data. The indication for event 320 can override the default preference for event 302.

[0055] Similar to the default preference discussed in conjunction with event 302, UE 102 can send a 320 preference to AMF 141 using a NAS message. AMF 141 can then forward this preference to SMF 142, and SMF 142 can configure UPF 143 based on this preference. Alternatively, if CN 120A is implemented as EPC, UE 102 can send a NAS message including an indication of downlink processing preferences to MME 131, which can then provide the preference to SGW 132. As an alternative to NAS messages, UE 102 can use RRC messages in both E-UTRAN and NG-RAN to specify preferences to RAN 105. In this implementation, base station 104 can forward this preference to AMF 141.

[0056] UE 102 can specify preferences for specific QoS flows or EPS bearers. UE 102 can also, alternatively, specify preferences for specific PDU sessions or PDN connections. For example, procedure 310 can involve PDU session S1 for a web browser and PDU session S2 for a video streaming application. In this case, UE 102 can send more than 320 PDU session-specific preferences, such as {{S1: buffer, drop}, {S2: buffer, buffer}}. Similarly, similar to the default preferences discussed above, UE 102 can specify buffer size limits for pending downlink data and / or newly arrived downlink data.

[0057] In some implementations, UE 102 sends preference 320 to CN 120A after establishing service with CN 120B. In other implementations, when sending preference 320, UE 102 cannot determine whether the service associated with the paging request of event 312 is SMS or a voice call, but CN 120A may be able to determine the service type later. In this scenario, UE 102 can specify corresponding preferences for multiple services, such as {{SMS: buffered, buffered}, {voice call: dropped, dropped}}. CN 120A can apply the appropriate preference when determining which service UE 102 switches to for another mobile network.

[0058] According to the specified preference, CN 120A buffers 340 pending downlink data (i.e., data that CN 120A has already received from the data source for UE 102 when CN 120A receives preference 320). CN 120A also buffers 342 newly arriving downlink data according to the preference.

[0059] Before buffering or discarding downlink data according to UE preferences, CN 120A determines in some implementations whether the preference conflicts with a relevant policy of CN 120A. Due to memory limitations, this policy can, for example, limit the UE's ability to buffer data at the CN. In some cases, the policy is UE-specific. When CN 120A determines that the UE preference is incompatible with the CN policy, CN 120A can determine that the CN policy takes precedence over the UE preference. In this case, CN 120A can notify UE 102 what policy CN 120A has applied, so that UE 102 knows how CN 120A will handle downlink data. In some of these implementations, CN 120A sends an acknowledgment for transmission 320, indicating whether CN 120A accepts UE 102's preference, and, if CN 120A does not fully accept the preference, what kind of modifications are made to the preference already applied by CN 120A.

[0060] Continue to refer to Figure 3 UE 102 communicates with CN 120B of the new mobile network PLMN2 330. UE 102 then reconnects 370 to the original mobile network PLMN1. CN 120A transmits 390 buffered downlink data, which in this case includes data packets that were pending at the time of event 320 as well as data packets that arrived after event 320.

[0061] Next, refer to the following: Figure 4-8 The discussions are typically similar to several scenarios in scenario 300. Events within these processes that are similar to those discussed above regarding process 300 are labeled with similar figure reference numerals (e.g., corresponding to...). Figure 3 Event 302 Figure 4 Event 402 or Figure 5 (Event 502). Besides Figure 4-8 The differences illustrated in the figure and described below, and any alternative implementations discussed above regarding process 300 (e.g., for message passing and processing), can be applied. Figure 4-8 The process.

[0062] refer to Figure 4Example scenario 400 is similar to scenario 300, but here UE 102 specifies different preferences for processing downlink data. In this scenario, UE 102 also determines 416 that UE 102 intends to process downlink data within a predetermined time period T. MAX After receiving information related to a paging request, UE 102 returns to CN 120A, but sends a different indication of downlink data processing preferences to CN 120A (421). In scenario 400, UE 102 specifies a preference to buffer pending downlink data but discard newly arrived downlink data. Based on this preference, CN 120A buffers pending downlink data (440) and discards newly arrived downlink data (443). After UE 102 reconnects to CN 120A (470), CN 120A delivers buffered downlink data (491), which in this case includes data packets that were pending at the time of event 320, but excludes data packets arriving after event 420.

[0063] Next, Figure 5 The illustration shows example scenario 500, which is similar to scenario 300, but in which UE 102 specifies another preference for processing downlink data. In this scenario, UE 102 also determines that UE 102 intends to process downlink data within a predetermined time period T. MAX After receiving the information related to the paging request, CN 120A is returned. However, UE 102 sends a preference (522) to discard pending downlink data but buffer newly arrived downlink data. CN 120A discards pending downlink data (541) but buffers newly arrived downlink data (542) according to this preference. After UE 102 reconnects to CN 120A (570), CN 120A transmits buffered downlink data (582), which in this case does not include data packets that were pending at the time of event 320, but includes data packets that arrived after event 420.

[0064] Figure 6 The illustration shows example scenario 600, which is similar to scenario 300, but in which UE 102 specifies another preference for processing downlink data. In this case, UE 102 also determines 617 that UE 102 does not intend to process downlink data during the predetermined time period T. MAX After receiving the information related to the paging request, UE 102 returns to CN 120A. Alternatively, UE 102 determines that 617 intends to [do something] within a predetermined time period T. MAXThe UE 102 returns to CN 120A, but also determines that downlink data received at CN 120A before the UE's return should be discarded. UE 102 sends 623 a preference to discard pending downlink data and newly arrived downlink data. CN 120A discards pending downlink data (641) and newly arrived downlink data (643) according to this preference. After UE 102 reconnects to CN 120A (670), CN 120A does not need to transmit downlink data missed by UE 102 while communicating with CN 120B.

[0065] Next, Figure 7 The illustration shows example scenario 700, which is similar to scenario 300, but in which UE 102 specifies its preference based on its intention to return to the original mobile network after a temporary connection to the new mobile network. UE 102 determines 716 that UE 102 intends to [do something] within a predetermined time period T. MAX After receiving information related to the paging request, UE 102 returns to CN 120A. UE 102 sends a 725 preference indication, specifying its intention to return to CN 102A. CN 120A then determines the preferred downlink data policy (720 preference) based on applicable CN rules and / or UE 102-specific settings. CN 120A buffers or discards pending downlink data (745) and newly arrived downlink data (746) based on the preference in event 725 and the determination in event 720. After UE 102 reconnects to CN 120A (770), CN 120A sends buffered downlink data (795) if applicable.

[0066] Figure 8 The illustration shows example scenario 800, which is similar to scenario 300, but in which UE 102 updates its preferences after specifying initial preferences to the originating mobile network. UE 102 determines 816 that UE 102 intends to [do something] within a predetermined time period T. MAX After receiving the information related to the paging request, the UE 102 returns to CN 120A. The UE 102 sends its initial preference P1 to CN 120A at 826 and activates timer 850, which is capable of having T... MAX The timeout period may have a fixed expiration time, or in some scenarios, a different expiration time. When timer 850 expires, UE 102 determines that communication process 830 with CN 120B is still in progress. In response, UE 102 sends an updated preference P2 to CN 120A. In some cases, the updated preference is the same as the original preference. In other cases, UE 102 changes its preference due to the expected expiration of an application-level timer; for example, this would cause the corresponding application to discard buffered data in any situation. Figure 8As illustrated, CN 120A buffers or discards pending downlink data 845 and buffers or discards newly arrived downlink data 846 according to the preference indicated in event 826, and then buffers or discards pending downlink data 847 and buffers or discards newly arrived downlink data 848 according to the preference indicated in event 827. If CN 120A has its own buffer size limit for storing downlink data of the UE, CN 120A can override the preferences of receiving 826 and 827 when the CN 120A buffer size exceeds the CN 120A buffer size.

[0067] For clarity, Figure 9 The diagram illustrates the message sequence for scenario 900, where the UE uses a NAS message to notify CN 120A of UE 102's downlink data processing preferences. Although UE 102 communicates with CN 120A indirectly only via the radio interface between UE 102 and RAN 105 (e.g., base station 104), in this scenario, RAN 105 does not process the downlink data processing preference indication and only forwards the preference to CN 120A.

[0068] on the other hand, Figure 10 The diagram illustrates the message sequence of scenario 1000, in which UE 102 sends RRC message 1061, which indicates UE 102's downlink data processing preferences, to RAN 105. Base station 104 or another node in RAN 105 processes this indication, formats an interface message including the indication (or an indication in a different format based on the indication received from UE 102), and sends the interface message 1062 to CN 120A.

[0069] For greater clarity, please refer to the following: Figure 11 and 12 discuss Figure 1 UE 102 and CN 120A can implement example methods to support the downlink data processing preferences of this disclosure. For example, these methods can be implemented as software instructions stored on a computer-readable medium and executed by one or more processors. Although these methods are discussed below with specific reference to UE 102 and CN 120A, these methods can also be implemented in other suitable devices.

[0070] First refer to Figure 11 When UE 102 switches to another mobile network, UE 102 can implement example method 1100 to request the mobile network to process downlink data according to UE 102's preferences. In box 1102, for those cases where UE 102 only temporarily switches to another mobile network (or switches to the same mobile network based on a different subscription) (see example...), Figure 3 Event 316 Figure 4 Event 416 Figure 5 Event 516 Figure 6 Event 617 Figure 7 Event 716 or Figure 8 In event 816, UE 102 determines the mobile network’s preference on how to process UE 102’s downlink data.

[0071] In box 1102, the UE sends a preference indication to CN 120A of the original mobile network (see example...). Figure 3 Event 302 or 320 Figure 4 Event 402 or 421 Figure 5 Event 502 Figure 6 Events 602 or 623 Figure 7 Event 702 or 725 Figure 8 Events 802, 826, or 827 Figure 9 Event 960 Figure 10 Event 1061).

[0072] at last, Figure 12 The diagram illustrates a flowchart 1200 of an example method in a mobile network for processing downlink data of UE 102 when UE 102 switches to another mobile network or the same mobile network based on a different subscription. In block 1202, for those cases where UE 102 only temporarily switches to another mobile network (see, for example...),... Figure 3 Event 302 or 320 Figure 4 Event 402 or 421 Figure 5 Event 522 or 502 Figure 6 Events 602 or 623 Figure 7 Event 702 or 725 Figure 8 Events 802, 826, or 827 Figure 9 Event 960 Figure 10 Event 1061), an indication of the mobile network’s preference on how the mobile network should process the downlink data of UE 102.

[0073] In box 1204, the mobile network determines that UE 102 has switched to another mobile network. To avoid confusion, the event associated with notifying CN120A that UE 102 has temporarily left PLMN1 is not shown separately; however, in some implementations, UE 102 includes indications regarding preferences for handling downlink data in the notification of UE 102's temporary departure from PLMN1 (see, for example...). Figure 3 Event 302 or 320 Figure 4 Event 402 or 421 Figure 5 Event 502 or 522 Figure 6 Events 602 or 623 Figure 7 Event 702 or 725 Figure 8 Events 802, 826, or 827 Figure 9 Event 960, Figure 10 Event 1061).

[0074] At box 1206, CN 120A processes the downlink data of UE 102 according to preferences (see example...). Figure 3 Events 340 and 342 Figure 4 Events 440 and 443 Figure 5 Events 541 and 542 Figure 6 Events 641 and 643 Figure 7 Events 745 and 746 Figure 8 (Events 845-848). As mentioned above, due to policy conflicts with CN, UE restrictions, exceeding data limits, etc., CN120A may not always meet the UE's preferences.

[0075] The following additional considerations apply to the foregoing discussion.

[0076] User equipment or UE (e.g., UE 102) capable of implementing the technologies of this disclosure can be any suitable device capable of wireless communication, such as a smartphone, tablet, laptop, mobile game console, point-of-sale (POS) terminal, health monitoring device, drone, camera, streaming dongle, or other personal media device, wearable device such as a smartwatch, wireless hotspot, femtocellular base station, or broadband router. Furthermore, in some cases, the user equipment can be embedded in electronic systems, such as a vehicle's audio head unit or advanced driver assistance system (ADAS). Further still, the user equipment can operate as an Internet of Things (IoT) device or a mobile internet device (MID). Depending on the type, the user equipment can include one or more general-purpose processors, computer-readable storage, a user interface, one or more network interfaces, one or more sensors, etc.

[0077] Some embodiments described in this disclosure include logic or multiple components or modules. A module can be a software module (e.g., code or machine-readable instructions stored on a non-transitory machine-readable medium) or a hardware module. A hardware module is a tangible unit capable of performing a specific operation and can be configured or arranged in a particular manner. A hardware module can include permanently configured dedicated circuitry or logic (e.g., as a dedicated processor, such as a field-programmable gate array (FPGA) or application-specific integrated circuit (ASIC), digital signal processor (DSP)) to perform certain operations. A hardware module may also include programmable logic or circuitry (e.g., encompassed within a general-purpose processor or other programmable processor) temporarily configured by software to perform certain operations. The decision to implement a hardware module in dedicated and permanently configured circuitry or in temporarily configured circuitry (e.g., configured by software) may be driven by cost and time considerations.

[0078] When implemented in software, this technology can be provided as part of an operating system, a library used by multiple applications, or a specific software application. This software can be executed by one or more general-purpose processors or one or more dedicated processors.

[0079] The following list of examples reflects various embodiments explicitly considered by this disclosure.

[0080] Example 1. A method in a UE having a first subscriber identity module for connecting to a first mobile network according to a first subscription and a second subscriber identity module for connecting to the first mobile network or a second mobile network according to a second subscription, the method comprising: determining by processing hardware a preference on how the first mobile network will process downlink data of the UE when the UE switches from the first subscription to the second subscription; and sending an indication of the preference to the first mobile network by the processing hardware such that the first mobile network processes the downlink data of the UE at least in part based on the preference.

[0081] Example 2. According to the method of Example 1, the sending is in response to detecting an event indicating that the UE will or has already switched from the first subscription to the second subscription.

[0082] Example 3. The method according to Example 2 further includes: in response to determining that the UE intends to return to the first subscription within a specific time period, assigning a first value to the indication; and in response to determining that the UE does not intend to return to the first subscription within the specific time period, assigning a second value to the indication.

[0083] Example 4. According to the method of Example 3, wherein determining that the UE intends to return to the first subscription within a specific time period includes detecting a paging request from the second subscription, the paging request relating to the Short Message Service (SMS).

[0084] Example 5. According to the method of Example 3, wherein determining that the UE intends to return to the first subscription within a specific time period includes detecting a paging request associated with the second subscription, the paging request involving a voice call.

[0085] Example 6. According to the method of Example 2, it further includes: assigning a value to the indication based on (i) determining whether the UE intends to return to the first subscription within a specific time period, and (ii) the default settings stored in the UE.

[0086] Example 7. According to the method of Example 6, the default settings specify: a first default action for pending downlink data and a second default action for newly arrived downlink data; wherein each of the first default action and the second default action is one of discard, buffer, or "don't care".

[0087] Example 8. The method according to Example 2 further includes: starting a timer in response to detecting an event; determining whether the UE has fulfilled its intention to return to the first subscription or remain in the second subscription in response to the timer expiring; and, in response to determining that the UE has not fulfilled its intention: the processing hardware determines how the first mobile network will process the UE's downlink data according to the updated preferences, and the processing hardware sends an indication of the updated preferences to the first mobile network.

[0088] Example 9. The method according to Example 1 includes: assigning a value to an indication based on default settings stored in the UE; and sending the indication of the preference before detecting an event indicating that the UE will switch from a first subscription to a second subscription.

[0089] Example 10. A method according to any of the preceding examples, wherein determining the preference includes determining whether the first mobile network should discard or retain all downlink data received from the core network (CN).

[0090] Example 11. A method according to any one of Examples 1-9, wherein determining the preference includes identifying one or more Protocol Data Unit (PDU) sessions or Packet Data Network (PDN) connections for which the first mobile network intends to discard or retain downlink data.

[0091] Example 12. A method according to any one of Examples 1-9, wherein determining the preference includes identifying one or more Quality of Service (QoS) streams or Evolved Packet Switching (EPS) bearers that the first mobile network should discard or retain downlink data.

[0092] Example 13. The method according to any of the preceding examples, wherein determining the preference includes determining whether pending downlink data should be buffered or dropped.

[0093] Example 14. The method according to any of the preceding examples, wherein determining the preference includes determining whether newly arriving downlink data should be buffered or dropped.

[0094] Example 15. A method according to any of the preceding examples, wherein sending the instruction includes sending a Non-Access Stratum (NAS) message to the CN of the first mobile network, the NAS message including the instruction.

[0095] Example 16. The method according to any of Examples 1-14, wherein the transmission instruction includes transmitting a message associated with a protocol for controlling radio resources.

[0096] Example 17. The method according to any of the preceding examples further includes: receiving an indication of a maximum time amount from a CN of a first mobile network, during which the CN is configured to buffer downlink data.

[0097] Example 18. The method according to any of the preceding examples further includes: receiving from the CN of the first mobile network an indication of the maximum buffer size of downlink data available to the UE at the CN.

[0098] Example 19. A user equipment (UE) including processing hardware and configured to implement any of the preceding examples.

[0099] Example 20. A method for processing downlink data of a user equipment (UE) in a first mobile network, the UE having a first subscriber identity module for connecting to the first mobile network according to a first subscription and a second subscriber identity module for connecting to the first mobile network or a second mobile network according to a second subscription, the method comprising: receiving from the UE by processing hardware an indication of how the UE prefers the first mobile network to process the UE's downlink data when the UE switches from the first subscription to the second subscription; and processing the UE's downlink data by the processing hardware at least in part based on the indication.

[0100] Example 21. According to the method of Example 20, receiving the instruction includes determining that the UE prefers the first mobile network to discard all downlink data received from the CN.

[0101] Example 22. According to the method of Example 20, receiving the instruction includes determining that the UE prefers the first mobile network to retain all downlink data received from the CN.

[0102] Example 23. According to the method of Example 20, the instruction specifies that the first mobile network should discard one or more PDU sessions or PDN connections of downlink data.

[0103] Example 24. According to the method of Example 20, the instruction specifies that the first mobile network should retain one or more PDU sessions or PDN connections for downlink data.

[0104] Example 25. According to the method of Example 20, the instruction specifies that the first mobile network should discard one or more QoS streams or EPS bearers of downlink data.

[0105] Example 26. According to the method of Example 20, the instruction specifies that the first mobile network should retain one or more QoS streams or EPS bearers for downlink data.

[0106] Example 27. A method according to any of Examples 20-26, wherein processing downlink data includes buffering pending downlink data.

[0107] Example 28. The method of Example 27 further includes: limiting the buffer based on at least one of (i) buffer size or (ii) time.

[0108] Example 29. A method according to any of Examples 20-26, wherein processing downlink data includes discarding pending downlink data.

[0109] Example 30. The method according to any one of Examples 20-29, wherein processing downlink data includes buffering newly arriving downlink data.

[0110] Example 31. The method according to any of Examples 20-29, wherein processing downlink data includes discarding newly arriving downlink data.

[0111] Example 32. The method according to any one of Examples 20-31 further includes: in response to determining that the indication has a first value, determining that the UE intends to return to the first mobile network within a specific time period.

[0112] Example 33. The method according to any one of Examples 20-31 further includes: in response to determining that the indication has a second value, determining that the UE does not intend to return to the first subscription within a predetermined time period.

[0113] Example 34. A method according to any of Examples 20-33, wherein receiving the instruction includes receiving a NAS message that includes the instruction.

[0114] Example 35. A method according to any of Examples 20-33, wherein receiving the instruction includes sending a message associated with a protocol for controlling radio resources.

[0115] Example 36. The method according to any one of Examples 20-35 further includes: detecting by processing hardware that the UE has switched from the first mobile network to the second mobile network.

[0116] Example 37. A base station that includes processing hardware and is configured to implement a method according to any one of Examples 20-36.

Claims

1. A method in a user equipment (UE), the UE having a first subscriber identity module for connecting to a first mobile network according to a first subscription and a second subscriber identity module for connecting to a second mobile network according to a second subscription, the method comprising: Switch from the first subscription to the second subscription; as well as In view of the aforementioned conversion, the UE sends an indication to the first mobile network of its preference on how the first mobile network should process the UE's downlink data, the indication of preference including: The first value for the first default action used for pending downlink data, and The second value for the second default action used for newly arrived downlink data.

2. The method according to claim 1, wherein: The conversion from the first subscription to the second subscription includes: In response to determining that the UE does not intend to return to the first subscription within a predetermined time period, the second value is assigned to the indication.

3. The method according to claim 1, wherein, In response to determining that the UE intends to return to the first subscription within a predetermined time period, the indication further includes the first value, wherein the determination includes detecting a paging request from the second subscription prior to the transition.

4. The method according to claim 1, further comprising: Based on (i) determining whether the UE intends to return to the first subscription within a predetermined time period, and (ii) a default setting stored at the UE, the indication includes either the first value or the second value, wherein the default setting specifies: The first default action for pending downlink data, and The second default action is used for newly arrived downlink data. Each of the first default action and the second default action is one of discard, buffer, or "don't care".

5. The method according to claim 1, wherein, The preference identifies one or more Protocol Data Unit (PDU) sessions or Packet Data Network (PDN) connections that the first mobile network wants to discard or retain downlink data from.

6. The method according to claim 1, wherein, The preference identifies one or more Quality of Service (QoS) streams or Evolved Packet Switching (EPS) bearers that the first mobile network should discard or retain for downlink data.

7. The method according to claim 1, wherein, The preference indicates whether the pending downlink data should be buffered or discarded.

8. The method according to claim 1, wherein, The preference indicates whether the newly arrived downlink data should be buffered or dropped.

9. The method according to claim 1, further comprising: Prior to the transition, an indication of a maximum time duration is received from the core network of the first mobile network, during which the core network is configured to buffer downlink data.

10. The method according to any one of claims 1 to 9, wherein, The second mobile network is the same as the first mobile network.

11. A user equipment (UE) including processing hardware and configured to implement the method of any one of claims 1 to 10.

12. A method for processing downlink data of a user equipment (UE) in a first mobile network, the method comprising: The first mobile network receives from the UE an indication of how the UE prefers the first mobile network to process the UE's downlink data when the UE switches from a first subscription with respect to the first mobile network to a second subscription with respect to the second mobile network, the indication including: The first value for the first default action used for pending downlink data, and The second value for the second default action used for newly arrived downlink data; and The first mobile network processes the downlink data of the UE at least in part based on the indication.

13. The method according to claim 12, wherein, The instruction specifies that the UE prefers the first mobile network to discard all downlink data received from the CN.

14. The method according to claim 12, wherein, The instruction specifies that the UE prefers the first mobile network to retain all downlink data received from the CN.

15. The method according to claim 12, wherein, The instruction specifies at least one of the following: (i) The first mobile network shall discard one or more PDU sessions or PDN connections for downlink data. (ii) The first mobile network shall retain one or more PDU sessions or PDN connections for downlink data. (iii) The first mobile network needs to discard one or more QoS streams or EPS bearers of downlink data, and (iv) The first mobile network shall retain one or more QoS streams or EPS bearers for downlink data.

16. A base station, including processing hardware and configured to implement the method of any one of claims 12-15.

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