WO2022089850A1

WO2022089850A1 - Mobile terminated service enhancements for musim user equipment

Info

Publication number: WO2022089850A1
Application number: PCT/EP2021/076209
Authority: WO
Inventors: Faranaz SABOURI-SICHANI; Nuno Manuel KIILERICH PRATAS; Srinivasan Selvaganapathy
Original assignee: Nokia Technologies Oy
Priority date: 2020-10-27
Filing date: 2021-09-23
Publication date: 2022-05-05

Abstract

Methods, user equipment and communication network for supporting MUSIM UEs in mobile terminated service wherein mapping information mapping paging indicators and paging cause is used to determine the operational mode of a user equipment.

Description

MOBILE TERMINATED SERVICE ENHANCEMENTS FOR MUSIM USER EQUIPMENT

Field

[0001] The subject matter described herein generally relates to communication systems and more particularly, to cellular communication systems including user equipment supporting multiple network subscriptions.

Background

[0002] User equipment UE may support more than one USIM (typically two, but not limited thereto), which may be from the same or from different Mobile (Virtual) Network Operators M(V)NOs.

[0003] While actively communicating with the first system, the UE needs to occasionally check the other system (e.g. to read the paging channel, perform measurements, or read the system information).

[0004] With the increased complexity of 5G-capable UEs and with growing demand for multi -USIM UEs in the market, enhancements supporting MUSIM UEs are of interest.

Summary

[0005] Please note that observations with respect to an aspect of the present disclosure, unless otherwise noted, correspondingly apply to any other aspect of the present disclosure even if not presented in connection therewith and, therefore, are not repeated.

[0006] According to an aspect, the present disclosure provides a method of operating a communication user equipment UE.

[0007] The user equipment UE may by capable of supporting a first network subscription USIM-A and a second network subscription USIM-B.

[0008] The UE operating method may comprise - receiving, at the user equipment UE, mapping information indicating mapping of at least one paging identifier I-RNTI, S-TMSI and at least one paging cause;

- operating the user equipment UE in an inactive or idle operational mode with respect to the first network subscription;

- monitoring, by the user equipment UE, for a paging message from the first communication network, the paging message including at least one of said at least one paging identifier I- RNTI, S-TMSI;

- determining, on the basis of the mapping information, a paging cause indicated by the said at least one of said at least one paging identifier I-RNTI, S-TMSI in the paging message,

- deciding on the basis of the determined paging cause whether

- to change from the inactive or idle operational mode of the first network subscription to an active operational mode of the first network subscription, or

- to maintain the inactive or idle operational mode of the first network subscription,

- sending a response to the paging message, based on the said decision, to the first communication network.

[0009] The UE operating method may further comprise

- operating the user equipment UE in an active operational mode with respect to the second network subscription; wherein

- the user equipment UE is not capable of sending data to a first communication network associated to the first network subscription without releasing the active operational mode with respect to the second network subscription;

- if changing from the inactive or idle operational mode of the first network subscription to the active operational mode of the first network subscription, the active operational mode with respect to the second network subscription is released;

- if maintaining the inactive or idle operational mode of the first network subscription on the basis of the determined paging cause, the active operational mode with respect to the second network subscription is maintained.

[0010] The UE operating method may further comprise

- sending a busy indication in the response to the paging message from the user equipment UE to the first communication network in the case it is decided to maintain the inactive or idle operational with respect to the first network subscription, the busy indication informing the first communication network that the user equipment UE remains the inactive or idle operational with respect to the first network subscription. [0011] Further, the busy indication may inform the first communication network that the user equipment UE has received the paging message.

The busy indication may be the response to the paging message (i.e. busy indication = response to paging message) or a part thereof (i.e. response to paging message includes busy indication) or sent to network along with the response to paging message (i.e. network receives (i) response to paging message and (ii) busy indication).

[0012] Further, the busy indication may be provided to the network as a result of a process at the UE following the reception of the paging message. For example, having received the paging message, the UE checks whether to remain in the inactive or idle operational mode or not. Having decided to remain in the inactive or idle operational mode, the buys indication may be sent to the network.

[0013] The UE operating method may further comprise

- sending, if it is determined to maintain the inactive or idle operational mode of the first network subscription, an identifier to the network, the indication indicating the determined paging cause.

[0014] The identifier may be the at least one paging identifier received with the paging message, or another identifier indicating the associated paging cause.

[0015] According to UE operating method, the mapping information may be received in encrypted or protected manner.

[0016] According to an aspect, the present disclosure provides a user equipment UE.

[0017] The user equipment UE may comprise

- at least one processor; and

- at least one memory including computer program code;

- the at least one memory and the computer code configured to, with the at least one processor, cause the apparatus at least to perform:

- support a first network subscription USIM; USIM-A and a second network subscription USIM, USIM-B,

- receive, at the user equipment UE, mapping information indicating mapping of at least one paging identifier I-RNTI, S-TMSI and at least one paging cause;

- operate the user equipment UE in an inactive or idle operational mode with respect to the first network subscription; - monitor, by the user equipment UE, for a paging message from the first communication network, the paging message including at least one of said at least one paging identifier I-RNTI, S-TMSI;

- determine, on the basis of the mapping information, a paging cause indicated by the said at least one of said at least one paging identifier I-RNTI, S-TMSI in the paging message,

- decide on the basis of the determined paging cause whether

- send a response to the paging message, based on the said decision, to the first communication network.

[0018] The user equipment UE may be in an active operational mode with respect to the second network subscription; wherein

[0019] The user equipment UE may be adapted to send a busy indication in the response to the paging message from the user equipment UE to the first communication network in the case it is decided to maintain the inactive or idle operational with respect to the first network subscription, the busy indication informing the first communication network that the user equipment UE remains the inactive or idle operational with respect to the first network subscription.

[0020] Further, the busy indication may inform the first communication network that the user equipment UE has received the paging message.

[0021] The busy indication may be the response to the paging message (i.e. busy indication = response to paging message) or a part thereof (i.e. response to paging message includes busy indication) or sent to network along with the response to paging message (i.e. network receives (i) response to paging message and (ii) busy indication).

[0022] Further, the busy indication may be provided to the network as a result of a process at the UE following the reception of the paging message. For example, having received the paging message, the UE checks whether to remain in the inactive or idle operational mode or not. Having decided to remain in the inactive or idle operational mode, the buys indication may be sent to the network.

[0023] The user equipment UE may be adapted send, if it is determined to maintain the inactive or idle operational mode of the first network subscription, an identifier to the network, the indication indicating the determined paging cause.

[0024] The identifier may be the paging identifier received with the paging message, or another identifier indicating the associated paging cause.

[0025] The user equipment UE may receive the mapping information in encrypted or protected manner.

[0026] According to an aspect, the present disclosure provides a method of operating a communication network capable of supporting a user equipment UE.

[0027] The user equipment UE may be capable of supporting a first network subscription USIM; USIM-A and a second network subscription USIM, USIM-B, the first network subscription being associate to the communication network.

[0028] The communication network operation method may comprise

- providing, to the user equipment UE, mapping information indicating mapping of at least one paging identifier I-RNTI, S-TMSI and at least one paging cause;

- sending a paging message from the communication network to the user equipment UE if being operated in an inactive or idle operational mode with respect to the first network subscription, the paging message including at least one of said at least one paging identifier I-RNTI, S-TMSI;

- receiving, at the communication network, a response from the user equipment UE to the paging message. [0029] In the communication network operation method, the response from the user equipment UE to the paging message may indicate that the user equipment UE changes from the inactive or idle operational mode of the first network subscription to an active operational mode of the first network subscription.

[0030] In the communication network operation method, the response from the user equipment UE to the paging message may indicate that the user equipment UE remains in the inactive or idle operational mode of the first network subscription.

[0031] In the communication network operation method, the response from the user equipment may be or include a busy indication indicating that that the user equipment UE remains in the inactive or idle operational mode of the first network subscription.

[0032] The busy indication may be the response to the paging message (i.e. busy indication = response to paging message) or a part thereof (i.e. response to paging message includes busy indication) or sent to network along with the response to paging message (i.e. network receives (i) response to paging message and (ii) busy indication).

[0033] Further, the busy indication may be provided to the network as a result of a process at the UE following the reception of the paging message. For example, having received the paging message, the UE checks whether to remain in the inactive or idle operational mode or not. Having decided to remain in the inactive or idle operational mode, the buys indication may be sent to the network.

[0034] The communication network operation method may comprise

- receiving an identifier from the user equipment (UE), the identifier indicating a paging cause to which said at least one of said at least one paging identifier (I-RNTI, S-TMSI) is mapped to.

[0001] The identifier may be the paging identifier received with the paging message, or another identifier indicating the associated paging cause.

[0002] According to the communication network operation method the mapping information may be provided in encrypted or protected manner.

[0003] According to an aspect, the present disclosure provides a communication network.

[0004] The communication network may comprise - at least one processor; and

- at least one memory including computer program code;

- support a user equipment UE, the user equipment UE being capable of supporting a first network subscription USIM; USIM-A and a second network subscription USIM, USIM-B, the first network subscription being associate to the communication network;

- provide, to the user equipment UE, mapping information indicating mapping of at least one paging identifier I-RNTI, S-TMSI and at least one paging cause;

- send a paging message from the communication network to the user equipment UE if being operated in an inactive or idle operational mode with respect to the first network subscription, the paging message including at least one of said at least one paging identifier I-RNTI, S- TMSI;

- receive, at the communication network, a response from the user equipment UE to the paging message.

[0005] In the communication network, the response from the user equipment UE to the paging message may indicate that the user equipment UE changes from the inactive or idle operational mode of the first network subscription to an active operational mode of the first network subscription.

[0006] In the communication network, the response from the user equipment UE to the paging message may indicate that the user equipment UE remains in the inactive or idle operational mode of the first network subscription.

[0035] In the communication network, the response from the user equipment may be or include a busy indication indicating that that the user equipment UE remains in the inactive or idle operational mode of the first network subscription.

[0036] Further, the busy indication may inform the first communication network that the user equipment UE has received the paging message.

[0037] The busy indication may be the response to the paging message (i.e. busy indication = response to paging message) or a part thereof (i.e. response to paging message includes busy indication) or sent to network along with the response to paging message (i.e. network receives (i) response to paging message and (ii) busy indication). [0038] Further, the busy indication may be provided to the network as a result of a process at the UE following the reception of the paging message. For example, having received the paging message, the UE checks whether to remain in the inactive or idle operational mode or not. Having decided to remain in the inactive or idle operational mode, the buys indication may be sent to the network.

[0007] The communication network may be adapted to

- receive an identifier from the user equipment (UE), the identifier indicating the paging cause to which said at least one of said at least one paging identifier (I-RNTI, S-TMSI) is mapped to.

[0008] The identifier may be the paging identifier received with the paging message, or another identifier indicating the associated paging cause.

[0009] The communication network may be adapted to

- provide the mapping information in encrypted or protected manner.

[0010] According to an aspect, the present disclosure provides a computer program comprising instructions stored thereon for carrying out the above user equipment operation method.

[0011] According to an aspect, the present disclosure provides a computer program comprising instructions stored thereon for carrying out the above communication network operation method.

[0012] According to a further aspect, a computer program product comprises program instructions stored on a computer readable medium to execute the method steps according to any one of the method embodiments outlined above when said program is executed on a computer.

[0013] The above-noted aspects and features may be implemented in systems, apparatuses, methods, articles and/or non-transitory computer-readable media depending on the desired configuration. The subject matter described herein may be implemented in and/or used with a number of different types of devices, including but not limited to cellular phones, tablet computers, wearable computing devices, portable media players, and any of various other computing devices. [0014] This summary is intended to provide a brief overview of some of the aspects and features according to the subject matter described in this document. Accordingly, it will be appreciated that the above-described features are merely examples and should not be construed to narrow the scope of the subject matter described herein in any way. Other features, aspects, and advantages of the subject matter described herein will become apparent from the following detailed description, drawings and claims.

Brief Description of the Drawings

[0015] A better understanding of the subject matter described herein can be obtained when the following detailed description of various embodiments is considered in conjunction with the following drawings, in which:

[0016] FIG. 1 illustrates a simplified wireless communication system in line with present disclosure.

[0017] FIG. 2 illustrates a base station (BS) in communication with a user equipment (UE) in line with present disclosure.

[0018] FIG. 3 illustrates a simplified block diagram of a UE in line with present disclosure.

[0019] FIG. 4a and 4b illustrates MUSIM scenarios.

[0020] Fig. 5 illustrates paging handling in line with the present disclosure.

[0021] Fig. 6 illustrates paging handling in line with the present disclosure.

[0022] Fig. 7 illustrates a flow diagram for a method in line with the present disclosure.

[0023] Fig. 8 illustrates a flow diagram for a method in line with the present disclosure.

Detailed Description [0024] FIG. 1 illustrates a simplified wireless communication system 100, according to some embodiments. It is noted that the system of FIG. 1 is merely one example of a possible system, and that features of the subject matter described herein may be implemented in any of various systems, as desired.

[0025] As shown, the wireless communication system 100 includes a base station 110-1 which communicates over a transmission medium with one or more user devices 120. In FIG. 1, only three user devices 120-1, 120-2, and 120-3 are shown, without limitation. Each of the user devices 120-1, 120-2, and 120-3 may be referred to herein as a "user equipment" (UE). Thus, the user devices 120 are referred to as UEs or UE devices.

[0026] As used herein, the term "user equipment" may refer to any of various types of computer systems devices which are mobile or portable and which perform wireless communications. Examples of UEs include mobile telephones or smart phones, portable gaming devices, laptops, wearable devices (e.g., smart watch, smart glasses), Personal Digital Assistants (PDAs), portable Internet devices, music players, data storage devices, or other handheld devices, etc. In general, the term "UE" or "UE device" can be broadly defined to encompass any electronic, computing, and/or telecommunications device (or combination of devices) which is easily transported by a user and capable of wireless communication.

[0027] The base station (BS) 110-1 may be a base transceiver station (BTS) or cell site (a "cellular base station"), and may include hardware that enables wireless communication with the UEs 120.

[0028] As used herein, the term "base station" has the full breadth of its ordinary meaning, and at least includes a wireless communication station installed at a fixed location and used to communicate as part of a wireless telephone system or radio system.

[0029] The communication area (or coverage area) of the base station 110 may be referred to as a "cell." The base station 110 and the UEs 120 may be configured to communicate over the transmission medium using any of various radio access technologies (RATs), also referred to as wireless communication technologies, or telecommunication standards, such as GSM, UMTS (associated with, for example, WCDMA or TD-SCDMA air interfaces), LTE, LTE-Advanced (LTE-A), 5G new radio (5G NR), HSPA, 3GPP2 CDMA2000 (e.g, IxRTT, IxEV-DO, HRPD, eHRPD), etc. If the base station 110-1 is implemented in the context of LTE, it may alternately be referred to as an "eNodeB" or "eNB". If the base station 110-1 is implemented in the context of 5G NR, it may alternately be referred to as "gNodeB" or "gNB".

[0030] As shown, the base station 110-1 may also be equipped to communicate with a network 130 (e.g., a core network of a cellular service provider, a telecommunication network such as a public switched telephone network (PSTN), and/or the Internet, among various possibilities). Thus, the base station 110-1 may facilitate communication between the user devices 120 and/or between the user devices 120 and the network 130. In particular, the cellular base station 110-1 may provide UEs 120 with various telecommunication capabilities, such as voice, SMS and/or data services.

[0031] The base station 110-1 and other similar base stations (such as base stations 110-2 and 110-3) operating according to the same or a different cellular communication standard may thus be provided as a network of cells, which may provide continuous or nearly continuous overlapping service to UEs 120 and similar devices over a geographic area via one or more cellular communication standards.

[0032] Thus, while base station 110-1 may act as a "serving cell" for UEs 120 as illustrated in FIG. 1, each UE 120 may also be capable of receiving signals from (and possibly within communication range of) one or more other cells (which might be provided by base stations 110 and/or any other base stations), which may be referred to as "neighboring cells". Such cells may also be capable of facilitating communication between user devices 120 and/or between user devices 120 and the network 130. Such cells may include "macro" cells, "micro" cells, "pico" cells, and/or cells which provide any of various other granularities of service area size. For example, base stations 110-1 and 110-2 illustrated in FIG. 1 might be macro cells, while base station 110-3 might be a micro cell. Other configurations are also possible.

[0033] In some embodiments, base station 110-1 may be a next generation base station, e.g., a 5G New Radio (5G NR) base station, or "gNB". In some embodiments, a gNB may be connected to a legacy evolved packet core (EPC) network and/or to a NR core (NRC) network. In addition, a gNB cell may include one or more transition and reception points (TRPs). In addition, a UE capable of operating according to 5GNR may be connected to one or more TRPs within one or more gNBs. [0034] The UE 120 may be capable of communicating using multiple wireless communication standards. For example, the UE 120 may be configured to communicate using a wireless networking (e.g., Wi-Fi) and/or peer-to-peer wireless communication protocol (e.g., Bluetooth, Wi-Fi peer-to-peer, etc.) in addition to at least one cellular communication protocol (e.g., GSM, UMTS (associated with, for example, WCDMA or TD-SCDMA air interfaces), LTE, LTE-A, 5G NR, HSPA, 3GPP2 CDMA2000 (e.g, IxRTT, IxEV-DO, HRPD, eHRPD), etc.). The UE 120 may also or alternatively be configured to communicate using one or more global navigational satellite systems (GNSS, e.g, GPS or GLONASS), one or more mobile television broadcasting standards (e.g, ATSC-M/H or DVB-H), and/or any other wireless communication protocol, if desired. Other combinations of wireless communication standards (including more than two wireless communication standards) are also possible.

[0035] FIG. 2 illustrates user equipment 120 (e.g, one of the devices 120-1, 120-2 and 120-3) in communication with a base station 110, according to some embodiments. The UE 120 may be a device with cellular communication capability such as a mobile phone, a handheld device, a computer or a tablet, or virtually any type of wireless device.

[0036] The UE 120 may include a processor that is configured to execute program instructions stored in memory. The UE 120 may perform any of the method embodiments described herein by executing such stored instructions. Alternatively, or in addition, the UE 120 may include a programmable hardware element such as a field-programmable gate array (FPGA) that is configured to perform any of the method embodiments described herein, or any portion of any of the method embodiments described herein.

[0037] The UE 120 may include one or more antennas for communicating using one or more wireless communication protocols or technologies. In some embodiments, the UE 120 may be configured to communicate using, for example, CDMA2000 (IxRTT/lxEV- DO/HRPD/eHRPD) or LTE using a single shared radio and/or GSM or LTE using the single shared radio. The shared radio may couple to a single antenna, or may couple to multiple antennas (e.g, for MIMO) for performing wireless communications. In general, a radio may include any combination of a baseband processor, analog RF signal processing circuitry (e.g, including filters, mixers, oscillators, amplifiers, etc.), or digital processing circuitry (e.g, for digital modulation as well as other digital processing). Similarly, the radio may implement one or more receive and transmit chains using the aforementioned hardware. For example, the UE 120 may share one or more parts of a receive and/or transmit chain between multiple wireless communication technologies, such as those discussed above. [0038] In some embodiments, the UE 120 may include separate transmit and/or receive chains (e.g., including separate antennas and other radio components) for each wireless communication protocol with which it is configured to communicate. As a further possibility, the UE 120 may include one or more radios which are shared between multiple wireless communication protocols, and one or more radios which are used exclusively by a single wireless communication protocol. For example, the UE 120 might include a shared radio for communicating using either of LTE or 5G NR (or LTE or IxRTT or LTE or GSM), and separate radios for communicating using each of Wi-Fi and Bluetooth™. Other configurations are also possible.

[0039] FIG. 3 illustrates a simplified block diagram of a UE 120, according to some embodiments. It is noted that the block diagram of the UE 120 of FIG. 3 is only one example of a possible user device. According to embodiments, UE 120 may be a user device, a mobile device or mobile station, a wireless device or wireless station, a desktop computer or computing device, a mobile computing device (e.g., a laptop, notebook, or portable computing device), a tablet and/or a combination of devices, among other devices.

[0040] As shown, the UE 120 may include a set of components configured to perform core functions. For example, this set of components may be implemented as a system on chip (SOC), which may include portions for various purposes. Alternatively, this set of components may be implemented as separate components or groups of components for the various purposes. The set of components may be coupled (e.g., communicatively; directly or indirectly) to various other circuits of the UE 120.

[0041] The UE 120 may include at least one antenna 312 in communication with a transmitter 314 and a receiver 316. Alternatively, transmit and receive antennas may be separate. The UE 120 may also include a processor 320 configured to provide signals to and receive signals from the transmitter 314 and receiver 316, respectively, and to control the functioning of the UE 120. Processor 320 may be configured to control the functioning of the transmitter 314 and receiver 316 by effecting control signaling via electrical leads to the transmitter 314 and receiver 316. Likewise, the processor 320 may be configured to control other elements of the UE 120 by effecting control signaling via electrical leads connecting processor 320 to the other elements, such as a display or a memory. The processor 320 may, for example, be embodied in a variety of ways including circuitry, at least one processing core, one or more microprocessors with accompanying digital signal processor(s), one or more processor(s) without an accompanying digital signal processor, one or more coprocessors, one or more multicore processors, one or more controllers, processing circuitry, one or more computers, various other processing elements including integrated circuits (for example, an application specific integrated circuit (ASIC), a field programmable gate array (FPGA), and/or the like), or some combination thereof. Accordingly, although illustrated in FIG. 3 as a single processor, in some example embodiments the processor 320 may comprise a plurality of processors or processing cores.

[0042] The UE 120 may be capable of operating with one or more air interface standards, communication protocols, modulation types, access types, and/or the like. Signals sent and received by the processor 320 may include signaling information in accordance with an air interface standard of an applicable cellular system, and/or any number of different wireline or wireless networking techniques, comprising but not limited to Wi-Fi, wireless local access network (WLAN) techniques, such as Institute of Electrical and Electronics Engineers (IEEE) 802.11, 802.16, 802.3, ADSL, DOCSIS, and/or the like. In addition, these signals may include speech data, user generated data, user requested data, and/or the like.

[0043] For example, the UE 120 and/or a cellular modem therein may be capable of operating in accordance with various first generation (1G) communication protocols, second generation (2G or 2.5G) communication protocols, third-generation (3G) communication protocols, fourth-generation (4G) communication protocols, fifth-generation (5G) communication protocols, Internet Protocol Multimedia Subsystem (IMS) communication protocols (for example, session initiation protocol (SIP) and/or the like. For example, the UE 120 may be capable of operating in accordance with 2G wireless communication protocols IS-136, Time Division Multiple Access TDMA, Global System for Mobile communications, GSM, IS-95, Code Division Multiple Access, CDMA, and/or the like. In addition, for example, the UE 120 may be capable of operating in accordance with 2.5G wireless communication protocols General Packet Radio Service (GPRS), Enhanced Data GSM Environment (EDGE), and/or the like. Further, for example, the UE 120 may be capable of operating in accordance with 3G wireless communication protocols, such as Universal Mobile Telecommunications System (UMTS), Code Division Multiple Access 2000 (CDMA2000), Wideband Code Division Multiple Access (WCDMA), Time Division-Synchronous Code Division Multiple Access (TD- SCDMA), and/or the like. The UE 120 may be additionally capable of operating in accordance with 3.9G wireless communication protocols, such as Long Term Evolution (LTE), Evolved Universal Terrestrial Radio Access Network (E-UTRAN), and/or the like. Additionally, for example, the UE 120 may be capable of operating in accordance with 4G wireless communication protocols, such as LTE Advanced, 5G, and/or the like as well as similar wireless communication protocols that may be subsequently developed. [0044] It is understood that the processor 320 may include circuitry for implementing au- dio/video and logic functions of the UE 120. For example, the processor 320 may comprise a digital signal processor device, a microprocessor device, an analog-to-digital converter, a dig- ital-to-analog converter, and/or the like. Control and signal processing functions of the UE 120 may be allocated between these devices according to their respective capabilities. The processor 320 may additionally comprise an internal voice coder (VC) 320a, an internal data modem (DM) 320b, and/or the like. Further, the processor 320 may include functionality to operate one or more software programs, which may be stored in memory. In general, the processor 320 and stored software instructions may be configured to cause the UE 120 to perform actions. For example, the processor 320 may be capable of operating a connectivity program, such as a web browser. The connectivity program may allow the UE 120 to transmit and receive web content, such as location-based content, according to a protocol, such as wireless application protocol (WAP), hypertext transfer protocol (HTTP), and/or the like.

[0045] The UE 120 may also comprise a user interface including, for example, an earphone or speaker 324, a ringer 322, a microphone 326, a display 328, a user input interface, and/or the like, which may be operationally coupled to the processor 320. The display 328 may, as noted above, include a touch sensitive display, where a user may touch and/or gesture to make selections, enter values, and/or the like. The processor 320 may also include user interface circuitry configured to control at least some functions of one or more elements of the user interface, such as the speaker 324, the ringer 322, the microphone 326, the display 328, and/or the like. The processor 320 and/or user interface circuitry comprising the processor 320 may be configured to control one or more functions of one or more elements of the user interface through computer program instructions, for example, software and/or firmware, stored on a memory accessible to the processor 320, for example, volatile memory 340, nonvolatile memory 342, and/or the like. The UE 120 may include a battery for powering various circuits related to the mobile terminal, for example, a circuit to provide mechanical vibration as a detectable output. The user input interface may comprise devices allowing the UE 120 to receive data, such as a keypad 330 (which can be a virtual keyboard presented on display 328 or an externally coupled keyboard) and/or other input devices.

[0046] As shown in FIG. 3, the UE 120 may also include one or more mechanisms for sharing and/or obtaining data. For example, UE 120 may include a short-range radio frequency (RF) transceiver and/or interrogator 364, so data may be shared with and/or obtained from electronic devices in accordance with RF techniques. The UE 120 may include other short-range transceivers, such as an infrared (IR) transceiver 366, a Bluetooth™ (BT) transceiver 368 operating using Bluetooth™ wireless technology, a wireless universal serial bus (USB) transceiver 370, a Bluetooth™ Low Energy transceiver, a ZigBee transceiver, an ANT transceiver, a cellular device-to-device transceiver, a wireless local area link transceiver, and/or any other short-range radio technology. The UE 120 and, in particular, the short-range transceiver may be capable of transmitting data to and/or receiving data from electronic devices within the proximity of the apparatus, such as within 10 meters, for example. The UE 120 including the Wi-Fi or wireless local area networking modem may also be capable of transmitting and/or receiving data from electronic devices according to various wireless networking techniques, including 6LoWpan, Wi-Fi, Wi-Fi low power, WLAN techniques such as IEEE 802.11 techniques, IEEE 802.15 techniques, IEEE 802.16 techniques, and/or the like.

[0047] The UE 120 may comprise memory, such as a subscriber identity module (SIM) 338, a removable user identity module (R-UIM), an eUICC, an UICC, and/or the like, which may store information elements related to a mobile subscriber. In addition to the SIM, the UE 120 may include other removable and/or fixed memory. The UE 120 may include volatile memory 340 and/or non-volatile memory 342. For example, the volatile memory 340 may include Random Access Memory (RAM) including dynamic and/or static RAM, on-chip or off- chip cache memory, and/or the like. The non-volatile memory 342, which may be embedded and/or removable, may include, for example, read-only memory, flash memory, magnetic storage devices, for example, hard disks, floppy disk drives, magnetic tape, optical disc drives and/or media, non-volatile random access memory (NVRAM), and/or the like. Like volatile memory 340, the non-volatile memory 342 may include a cache area for temporary storage of data. At least part of the volatile and/or non-volatile memory may be embedded in the processor 320. The memories may store one or more software programs, instructions, pieces of information, data, and/or the like which may be used by the apparatus for performing operations disclosed herein.

[0048] The memories may comprise an identifier, such as an International Mobile Equipment Identification (IMEI) code, capable of uniquely identifying the UE 120. The memories may comprise an identifier, such as an international mobile equipment identification (IMEI) code, capable of uniquely identifying the UE 120. In the example embodiment, the processor 320 may be configured using computer code stored at memory 340 and/or 342 to cause the processor 320 to perform operations disclosed herein.

[0049] Some of the embodiments disclosed herein may be implemented in software, hardware, application logic, or a combination of software, hardware, and application logic. The software, application logic, and/or hardware may reside on the memory 340, the proces- sor 320, or electronic components, for example. In some example embodiment, the application logic, software or an instruction set is maintained on any one of various conventional computer-readable media. In the context of this document, a "computer-readable medium" may be any non-transitory media that can contain, store, communicate, propagate or transport the instructions for use by or in connection with an instruction execution system, apparatus, or device, such as a computer or data processor circuitry, with examples depicted at FIG. 3, computer-readable medium may comprise a non-transitory computer-readable storage medium that may be any media that can contain or store the instructions for use by or in connection with an instruction execution system, apparatus, or device, such as a computer.

[0050] The present disclosure related to support of MUSIM (Multiple U-SIM) in the context of 3 GPP Release 17 study and work items to provide 3 GPP support of MUSIM devices (see. 3GPP documentation: SP-190248, "Study on system enablers for multi-USIM devices (FS MUSIM)", TR 22.834, TR 23.761 (each of which being incorporated by reference - at least for jurisdictions where such incorporation is allowable)). Yet more particularly, the present disclosure may be considered as providing inventive solutions with respect to 3GPP standard specifications TS 38.331 and TS 38.413 (each of which being incorporated by reference - at least for jurisdictions where such incorporation is allowable).

[0051] User equipment UE may support more than one USIM (typically two, but not limited thereto), which may be from the same or from different Mobile (Virtual) Network Operators M(V)NOs.

[0052] While actively communicating with a first system to which a first USIM is associated to, the UE needs to occasionally check the other system of the second system, e.g. to read the paging channel, perform measurements, or read the system information.

[0053] Paging Occasions (POs) are calculated based on the UE identifier (IMSI and 5G- S-TMSI for EPS and 5GS, respectively).

[0054] When the UE receives a page in a first system to which a first USIM is associated, while being in connected mode in second system to which a second USIM is associated to, it would helpful for the UE to decide whether it should respond to the page.

[0055] When the UE decides to respond to the page in the first system, or when the UE needs to perform some signaling activity in the first system (e.g. Periodic Mobility Registration Update), the UE may need to stop the current activity in the second system related to the second USIM. This may result in a release of the connection (e.g. RRC connection) in the second system, what may be interpreted as an error case and may have the potential to distort the statistics.

[0056] On the other hand, if the UE does not respond to the page in the first system related to the first USIM, the first system will keep paging the UE which will result in waste of paging resources.

[0057] Fig. 4a illustrates a multi-USIM user equipment UE (MUSIM UE) having two (Dual) or more (Multiple) simultaneous 3GPP/3GPP2 network subscriptions each associated with a particular subscription belonging to the same Mobile Network Operator (MNO (/Mobile Virtual Network Operator (MVNO)).

[0058] Fig. 4b illustrates a multi-USIM user equipment UE (MUSIM UE) having two (Dual) or more (Multiple) simultaneous 3GPP/3GPP2 network subscriptions each associated with a particular subscription belonging to different Mobile Network Operator (MNO (/Mobile Virtual Network Operator (MVNO)).

[0059] A UE SIM (USIM) may be a physical SIM or an eSIM. A MUSIM UE may include two or more physical SIMs or two or more eSIMs or combinations thereof (e.g. one or more physical SIM and one or more eSIM).

[0060] In the case of EPS, the network subscriptions respectively may have corresponding International Mobile Subscriber Identities (IMSI). In the case of 5GS, the network subscriptions respectively may have corresponding Subscription Permanent Identifier (SUPI).

[0061] As illustrated in Fig. 4a, the MUSIM UE is connected to one or more bases stations (e.g. gNB) with two subscriptions belonging to the same MNO/MVNO and registered with two independent IDs at the core network. The MUSIM UE may be using the same cell or two neighboring cells as serving cell. The latter scenario may occur, e.g., if MUSIM UE is in a range between two or more cells, where, due to e.g. load balancing or the handover procedures, one subscription gets assigned to a cell while the other subscription gets assigned to another.

[0062] As illustrated in Fig. 4b, the MUSIM UE is connected to one or more bases stations (e.g. gNB) with two subscriptions belonging to different MNOs/MVNOs and may be using two neighboring or co-located cells from each MNO as serving cell. [0063] The following indicates, in exemplary and not limiting manner, different types of MUSIM UEs, which types are often referred to depending on the supported simultaneous RRC states on the USIMs:

Dual SIM Dual Standby (DSDS) or Multi USIM Multi Standby (MUMS)

MUSIM UE

- is registered with two or more independent subscriber IDs (USIMs)

- can be in RRC IDLE mode on all USIMs

- can only be in RRC CONNECTED mode with a single USIM at a given time

Dual SIM Dual Active (DSD A) or Multi USIM Multi Active (MUMA) MUSIM UE

- is registered with two or more independent subscriber IDs (USIMs)

- can be in RRC IDLE mode on all USIMs

- can maintain RRC CONNECTED mode activities on all USIMs

[0064] The behavior of a UE with respect to the simultaneous handling of multiple USIMs may depend on the UEs capabilities as listed below:

SingleRx / SingleTx

UE is capable of receiving traffic from one network and/or transmitting traffic to the same or another network at a time (type 1).

DualRx / SingleTx

UE is capable of simultaneously receiving traffic from two networks but is capable of transmitting to only one of the networks at a time (type 2).

DualRx /DualTx

UE is capable of simultaneously receiving and/or transmitting to/from two different networks (type 3).

[0065] Usually, the maximum number of supported USIMs is two (2). However, there are implementations that may support three or more SIMs. With the introduction of electronic SIM (e-SIM), it is to be expected that some phones will arrive to the public market with support for more than two USIMs. For the present disclosure, reference is made to MUSIM UEs supporting two USIMs. However, this is just for illustration and not limiting in any way; rather, the teachings of the present disclosure also apply to UEs supporting more than two USIMs, e.g. three, four, five, ... USIMs.

[0066] An aspect associated with MUSIM operation is that a UE being not dualRx/Du- alTx capable needs to (time) share their resources to support concurrent activities across both USIMs in case they happen to collide in time.

[0067] For example, a UE capable of singleRx/SingleTx cannot concurrently take into account signaling related to two USIM. For example, it cannot read SIBs (System Information Blocks), perform Radio Resource Management (RRM) measurements or monitor pagings in relation to two USIM.

[0068] Further, a UE capable of singleRx/SingleTx or dualRx/SingleTx cannot maintain two RRC connections simultaneously without interruption. In such cases (i.e. where the UE does not allow/ support the operation of multiple simultaneous active RRC connections), then, when a USIM is in RRC Connected mode, the other USIM(s) have to be in either RRC Idle or RRC Inactive mode.

[0069] For example, assume a DSDS UE having an active connection (RRC Connected mode) for a first USIM A and being in idle mode operation in a second USIM B, then the following scenario may be possible:

[0070] The UE instance associated with the idle mode USIM, i.e. USIM B, receives a paging message from a network B to which the USIM B is associated to.

[0071] The UE releases locally the RRC connection associated with the USIM A that is connected to a network A to which the USIM A is associated to.

[0072] Triggers uplink access (i.e. RACH procedure to transition the USIM previously in RRC Idle/Inactive) to send a Service Request as a paging response for the received paging.

[0073] As the paging reception is considered as a priority event for the MUSIM device, the ongoing RRC connection associated with the USIM in RRC Connected is dropped locally according to the above described behavior. [0074] An issue associated with the above described behavior may be that the UE can leave the USIM in RRC Connected, while an active data transmission for high priority services such as voice is taking place, in order to respond to a paging message which may be for lower priority data services. This will lead to high priority service on one USIM pre-empting the ongoing lower priority service on the other USIM.

[0075] On the other hand, if the UE does not respond to the paging message from the network B to which the USIM B is associated to, then redundant as paging retransmissions will lead to wastage of radio resource for paging the UE due to not responding to the paging message; also, the network B may mark the UE as not reachable for further mobile terminated services.

[0076] To this end, it is contemplated that the UE can send a BUSY indication to the paging network and switch back to the connected mode operation instead of accepting the paging message and initiating SERVICE REQUEST (see e.g. 3 GPP documents SP-1912408 and TR 23.761, which are incorporated by reference - at least for jurisdictions where such incorporation is allowable). This approach would require the UE to setup an RRC connection in the paging network, which will still create an interruption to the ongoing RRC connection.

[0077] In addition, the paging message may indicate the paging cause by including a paging cause value in the paging message. This might result in security issues. To this end, it might be an approach to include security aspects using existing security mechanisms in the paging message, what however increases the paging record size by at least minimum of 2-4 bytes and thus will also impact the paging efficiency of RRC paging.

[0078] The present disclosure relates to a modification on how the paging towards a non RRC-Connected state USIM is done in order to address the above-noted aspect of an interruption of an ongoing RRC CONNECTED mode for a USIM of a UE supporting two USIMs when a paging message is addressed to the other USIM being in RRC INACTIVE or RRC IDLE state.

[0079] The modification disclosed here includes at least the following aspects:

[0080] One or several alternative paging identifiers (e.g. I-RNTI or S-TMSI) are assigned at the network side (e.g. at Radio Access Node RAN or Core Network CN) for paging towards a UE. Such an assignment may be based on a mapping of one or more paging causes to an identifier towards a MUSIM capable device UE. [0081] Identification of a paging cause at a UE in RRC INACTIVE or RRC IDLE state based on the paging identifier (e.g. the I-RNTI or S-TMSI) and its association to paging cause(s).

[0082] For a UE having a USIM in RRC INACTIVE or RRC IDLE mode, the UE may send - in response to a paging message to RRC INACTIVE or RRC IDLE mode USIM - a BUSY indication message to the network from which a paging message to RRC INACTIVE or RRC IDLE mode USIM comes from using a response (e.g. RRCResumeRequest or RRCSetupRequest) indicating towards the network that the UE has received the paging message but will remain in its inactive or idle operational mode and not enter an active operational mode. The BUSY indication may include the LRNTI or S-TMSI that was received with the paging message.

[0083] The UE may apply an alternative identifier in its response to avoid potential attacker to transmit a response on behalf of the valid UE. For example, an identifier differing from the LRNTI received with the paging message may be used. In such cases, the identifier also indicated the paging cause associated to the received paging message. However, using an identifier differing from the received LRNTI avoids (or makes it at least harder) for an intruder or interceptor that has got the paging message to reply on behalf of the UE to which the paging message was addressed to. An identifier differing from the received I-RNTI, for example, may be agreed upon between the UE and the network, or defined at the network side and notified to the UE, or defined at the UE side and notified to the network.

[0084] A BUSY indication may, as set forth, send - as such or as part of a response message - as a direct response to the paging message.

[0085] However, it is also possible that a BUSY indication is sent to the network as a result of, e.g., a process at the UE. For example, a BUSY indication may be sent as a result of the UE having determined that it will remain in the inactive or idle operational mode of the USIM (USIM- A) to which the paging message was sent and to not release an ongoing active operational mode of another USIM (USIM-B). In such cases, the busy indication may be sent as such or as part of a message to the network. [0086] Fig. 5 illustrates a scenario where one or more new paging identifiers are created and associated to paging cause(s) having high priority; in other words, the new paging identifier indicates that the paging cause has high priority. More observations with respect to priority of paging causes can be found down below.

[0087] For Fig. 5, it is assumed that the UE supports at least two USIMS. Further, it is assumed that - in the course of the scenario - the UE receives a paging message for one of the USIMS, while at least one of the other USIMs is in RRC CONNECTED mode when - as set forth below - steps 13, 14 and 15 of Fig. 5 take place.

[0088] Fig. 5 illustrates steps associated for that USIM of UE to which the paging message relates to (in the following USIM-A).

[0089] Further, it is assumed that the UE is a Dual SIM Dual Standby (DSDS) or Multi USIM Multi Standby (MUMS) UE, where the UE can only be in RRC_CONNECTED mode with a single USIM at a given time. For such cases, the Fig. 5 scenario allows the UE to listen to paging messages for a USIM being in RRC INACTIVE or RRC IDLE mode and to respond only to paging messages being classified as paging message the UE has to react to, so that an ongoing RRC CONNECTED mode of another USIM (also referred to a USIM-B) is only interrupted when necessary. Paging messages are generally monitored by the UE for all its USIMs. However, paging messages related to a USIM being in RRC INACTIVE or RRC IDLE mode and not being classified as paging message the UE has to react to do not result in reaction of the UE.

[0090] The scenario of Fig. 5 is also applicable to a Dual SIM Dual Active (DSD A) or Multi USIM Multi Active (MUMA) MUSIM UE, where the UE can maintain RRC CON- NECTED mode activities on all USIMs. One might say, for such cases the UE could listen and respond to all paging massages since a response to a paging message for an USIM does not necessarily result in an interruption of an ongoing RRC CONNECTED mode of another USIM, because parallel RRC CONNECTED modes can be supported. However, using the present disclosure may be also helpful here. Responding to a paging message need resources of the UE. Thus, limiting response to paging messages so that only paging messages being classified as paging message the UE has to react to are replied to reduce the resource usage.

[0091] Priorities may be defined in relation to the operational status of another USIM-B, for example, in relation to ongoing traffic with respect to the other USIM-B. [0092] For example, if USIM-B has ongoing communication where an interruption would be problematic or not tolerable (e.g. voice communication), then the UE may not respond to a paging message towards USIM-A in order to avoid an impact on the USIM-B communication. In such cases, the UE may only respond to paging messages towards USIM-A if the paging cause has an overriding priority (e.g. emergency services).

[0093] If USIM-B has ongoing communication where an interruption would be not problematic or tolerable (e.g. data communication where an interruption can be masked or is even not noticed at the user side), then the UE may respond to a paging message towards USIM-A if that result in an unproblematic or tolerable interruption of USIM-B communication.

[0094] In Step 1 of Fig. 5, the UE being in RRC IDLE mode and CM-IDLE mode for a USIM (in the following USIM-A) sends a request to establish RRC CONNECTED for USIM-A to the network to which the USIM-A is associated to. This so-called RRCSetupRe- quest is addressed, to or via a gNB.

[0095] In step 2a of Fig. 5, the network (e.g. gNB) returns setup information RRCSetup to the UE on the basis of which the UE enters the RRC CONNECTED mode for the USIM- A.

[0096] In step 2b of Fig. 5, the UE informs the network (e.g. at or via gNB) that the RRC CONNECTED mode setup is completed.

[0097] At step 3 of Fig. 5, the UE context procedure with the network takes place. For the here assumed network, the UE context procedure takes place with respect to an Access and Mobility Function AMF.

[0098] As part of the UE context procedure, the network receives a request to indicate at least one possible paging cause that can be sent from the network to the UE, e.g. when the network initiates downlink data towards the UE when the UE is an RRC INCATIVE mode for its USIM (e.g. in an EMM-SUSPENDED mode).

[0099] For the network assumed this indication is send as INITIAL UE message from the gNB towards the AMF.

[0100] In steps 4a and 4b of Fig. 5, information with respect to downlink DL communication is provided from the network to the UE. This is also part of the UE context procedure. [0101] In steps 5a and 5b of Fig. 5, information with respect to uplink UL communication is provided from the UE to the network. This is also part of the UE context procedure.

[0102] Step 6 of Fig. 5 is also part of the UE context procedure. In step 6 of Fig. 5, the network issues an Initial Context Setup request that includes the indication of said above at least one possible paging cause towards the UE. According to the assumed network of Fig. 5, the Initial Context Setup request is sent from the AMF to the gNB. Since the indication of said above at least one possible paging cause towards the UE is stored in the UE context, the indication can follow the UE while it remains in the RAN-based Notification Area RNA.

[0103] It is possible that the network also provides a respective priority for the at least one possible paging cause and/or, if there are more than one paging causes, a priority (i.e. which paging cause has a higher/lower priority in relation to another paging cause, or paging has higher priority than other operation of UE, e.g., active operational mode of USIM-B).

[0104] References in the following to "said above at least one possible paging cause towards the UE" includes that the network provides the at least one possible paging cause as such (i.e. just the paging cause(s)) or provides the at least one possible paging cause together with a respective priority.

[0105] In step 7 of Fig. 5, the indication of said at least one possible paging cause towards the UE is stored in the UE context. Here, the UE context is stored at the gNB.

[0106] Steps 8a and 8b of Fig. 5 relate to security related communication between the network and the UE.

[0107] Steps 9a and 9b of Fig. 5 relate to configuration measures, e.g. RRCReconfigura- tion.

[0108] In step 10 of Fig. 5, the network is informed that the UE context is completed.

[0109] Following step 10 of Fig. 5, the USIM-A of the UE is in RRC CONNECTED mode. [0110] As indicated by step 11 of Fig. 5, during the USIM-A RRC CONNECTED mode, at least before it is terminated, the network creates or configures a paging identifier, here at least one so-called Inactive Radio Network Temporary Identifier I-RNTI.

[0111] According to Fig. 5, this is accomplished by the gNB.

[0112] I-RNTIs may be defined for each of said above at least one possible paging cause towards the UE (i.e. one I- RNTI for one indicated possible paging cause), and/or a group of said above at least one possible paging cause towards the UE (i.e. an I- RNTI for more than one indicated possible paging causes), and/or for all said above at least one possible paging cause towards the UE (i.e. one I- RNTI for all indicated possible paging causes).

[0113] In other words, the network creates a mapping of I-RNTI(s) to paging cause(s). In cases, where the network has provided respective priorities and/or priority orders, the mapping also maps I-RNTI(s) to priority(ies).

[0114] Here and throughout the present disclosure a response or reply to paging with an I-RNTI means that the UE, for the related USIM, establishes a communication link to the network by means of which communication link the UE can send data to the network and control messages (like a response to a paging message). Such an operational mode is also referred to as active operational mode. For example, in the framework of Fig. 5, such a communication link may be RRC CONNECTED mode for USIM-A.

[0115] Here and throughout the present disclosure UE not responding or replying to paging with an I-RNTI means that the UE, for the related USIM, does not establish a communication link to the network by means of which communication link the UE can send data to the network, but maintains the operational mode in which the UE receives paging messages and can confirm the receipt thereof along with indication that it will not respond. Such operational modes are also referred to inactive or idle operational modes. For example, in the framework of Fig. 5, such an operational mode link may be RRC INCATIVE or RRC IDLE mode for USIM-A. In such cases, the UE maintains the inactive or idle operational mode and informs the network that it has received the paging message but that it remains inactive or idle. [0116] In principle, one paging identifier and one paging cause may be used. Such cases include, e.g., that the network subscription for USIM-A covers a single service (e.g. only video streaming, only emergency calls). In such cases, the UE having received the paging message with the paging identifier may, for example, decide whether the underlying paging cause (e.g. the network wants to provide video streaming or emergency call service) is more important than an ongoing RRC connection of another USIM-B or replying to the paging message would affect an ongoing RRC connection of another USIM-B in a manner not desired or to be avoided.

[0117] In practice, it may by the at least two paging identifiers and at least two paging causes are used. This allows, for example, to have paging messages having a paging identifier in view of which the UE leaves the inactive or idle operational mode and enters an active operational mode, wherein an ongoing RRC connection of another USIM-B may be released, and paging messages having another paging identifier in view of which the UE remains in the inactive or idle operational mode, wherein an ongoing RRC connection of another USIM-B may be maintained. For example, a paging identifier may be indicative of paging causes resulting in a relatively short release of an ongoing RRC connection of another USIM-B so that a service provided via that RRC connection is not affected in an unacceptable manner (e.g. short release of voice communication that is not noted by user); another paging identifier may be indicative of paging causes resulting in a relatively long release of an ongoing RRC connection of another USIM-B so that a service provided via that RRC connection is affected in an unacceptable manner (e.g. release of voice communication to be too long to be not noted by user).

[0118] Two I-RNTIs may be used, wherein a first I-RNTI can be considered to indicate a first group of one or more paging causes and a second I-RNTI can be considered to indicate a second group of one or more paging cause. For example, the first group may cover one or more paging causes having a high(er) priority, while the second group may cover one or more paging causes having a low(er) priority. Groups of paging causes may be (also) defined with respect to, e.g. an associated service, like voice/VoIP, IMS, other Data, with respect to which the reaction of the UE may differ.

[0119] Also more than two I-RNTIs may be used, to which cases the above observations with respect to more than two I-RNTIs correspondingly apply to. [0120] The UE may take into account the situation as regards another USIM-B. assume, for example, USIM-B of the UE is in operational active mode (e.g. RRC CONNECTED mode) servicing an ongoing voice communication with the network, while a paging message towards USIM-A is received at the UE. On the basis of the I-RNTI of the received paging massage and the mapping information at the UE, the UE may determine which paging cause is associated to the received I-RNTI. Depending on the determined paging cause (e.g. voice, streaming, other data), the UE may decide to whether to respond to the paging and move to RRC connected in USIM-A or to maintain the RRC INACTIVE or RRC IDLE mode of USIM-A. Such decisions may be based on determinations, for example, that the paging cause has a higher priority, that the paging cause results in a tolerable interruption of the USIM-B connection, that the paging cause has a lower priority or that the paging cause results in an intolerable interruption of the USIM-B connection.

[0121] In step 12 of Fig. 5, the mapping information is provided to the UE. As a result, the UE gets information which I-RNTI is associated to which possible paging cause(s).

[0122] According to step 12 of Fig. 5, the mapping information may be added to the information element suspicioning in RRCRelease message from the network to the UE.

[0123] In the case security measures have been established before, the mapping can be communicated in privacy to the UE.

[0124] For example, according to Fig. 5, in steps 8a and 8b AS security activation takes place. Due to the AS security activation, the mapping information can be forwarded to the UE via RRC signaling, whereby the above addressed privacy is resolved.

[0125] Following step 12 of Fig. 5, USIM-A of the UE enters the RRC INACTIVE mode (or RRC IDLE mode).

[0126] In the RRC INACTIVE mode (or RRC IDLE mode), as indicated by step 13 of Fig. 5, there are paging occasions PO where the UE monitors for LRNTI(s) from the network, according to Fig. 5 the gNB.

[0127] In steps 14 and 15 of Fig. 5, the network issues a paging towards the UE utilizing one of said above LRNTIs depending on the paging cause. [0128] According to Fig. 5, in the step 14 the AMF forwards a paging trigger and the paging cause to the gNB. The gNB sends, in step 15 of Fig. 5, a paging message including the I-RNTI associated to the paging cause to the UE.

[0129] When the UE receives the paging message and, thus, having an I-RNTI of the mapping information, the UE may determine - on the basis of the I-RNTI the paging is sent with - which paging cause is associated thereto.

[0130] Then, it can be decided whether the UE, with respect to USIM-A, leaves the RRC INACTIVE or RRC IDLE mode and enters RRC CONNECTED mode, or remains in the RRC INACTIVE or RRC IDLE mode for USIM-A.

[0131] The UE may monitor, on its paging occasion, for the number of LRNTIs received from the network at the same time. This does not decrease the paging record capacity as the network only activates one I-RNTI at a time.

[0132] Having determined that it remains in the RRC INACTIVE or RRC IDLE mode, the UE may inform the network that the UE it remains in the RRC INACTIVE or

RRC IDLE mode. This information taken alone may by an indication for the network that the UE has received the paging message. The receipt confirmation may be also provided as separate information to the network.

[0133] Having the receipt information the network will not consider the paging massage as being lost, what could result in further attempt to page the UE again. Rather, the network can consider this paging message as resolved.

[0134] The busy indication may be sent to the network as such (i.e. alone) or as part of a response message towards the network, in both cases in (so to say direct) response to the paging message.

[0135] Further, the busy indication - taken alone or part of a message - may be triggered by a process following the reception of the paging message. In such cases, it can be said that the busy indication is sent so to say indirectly in response to the paging message. For example, the busy indication may be sent to the network when, for example, at the UE a process following the reception of the paging message comes to the conclusion that the UE remains in the RRC INACTIVE or RRC IDLE mode. [0136] The busy indication may include an identifier indicating the paging cause associated to the received paging message or may be provide together with such an identifier. As such identifier, the I-RNTI received with the paging message may be used.

[0137] Further, an identifier differing from the I-RNTI received with the paging message may be used. In such cases, the identifier also indicated the paging cause associated to the received paging message. However, using an identifier differing from the received I-RNTI avoids (or makes it at least harder) for an intruder or interceptor that has got the paging message to reply on behalf of the UE to which the paging message was addressed to.

[0138] An identifier differing from the received I-RNTI, for example, may be agreed upon between the UE and the network, or defined at the network side and notified to the UE, or defined at the UE side and notified to the network.

[0139] Fig. 6 also illustrates steps associated for that USIM of UE to which the paging message relates to (in the following USIM-A). All observations above, particular those with respect to Fig. 5, also apply here in the following and, therefore, are not repeated.

[0140] Further, it is assumed that the UE is a Dual SIM Dual Standby (DSDS) or Multi USIM Multi Standby (MUMS) UE, where the UE can only be in RRC_CONNECTED mode with a single USIM at a given time. For such cases, the Fig. 5 scenario allows the UE to listen to paging messages for a USIM being in RRC IDLE mode and to respond only to paging messages being classified as paging message the UE has to react to, so that an ongoing RRC CONNECTED mode of another USIM is only interrupted when necessary. Paging messages are generally monitored by the UE for all its USIMs. However, paging messages related to a USIM being in RRC IDLE mode and not being classified as paging message the UE has to react to do not result in reaction of the UE.

[0141] The scenario of Fig. 6 is also applicable to a Dual SIM Dual Active (DSDA) or Multi USIM Multi Active (MUMA) MUSIM UE, where the UE can maintain RRC CON- NECTED mode activities on all USIMs. One might say, for such cases the UE could listen and respond to all paging massages since a response to a paging message for an USIM does not necessarily result in an interruption of an ongoing RRC CONNECTED mode of another USIM, because parallel RRC CONNECTED modes can be supported. However, using the present disclosure may be also helpful here. Responding to a paging message need resources of the UE. Thus, limiting response to paging messages so that only paging messages being classified as paging message the UE has to react to are replied to reduce the resource usage. [0142] The above observation with respect to priorities correspondingly apply here also.

[0143] Fig. 6 particularly relates to cases where the network addresses the UE on a core network level. This may be the case of Non-Access Stratum NAS where communication between core network (nodes) and user equipment takes place. In such cases, usually the UE is in an idle mode. According to the present disclosure this may be RRC IDLE mode.

[0144] For addressing the UE, the network uses the IMSI of the UE, for example in form of S-TMSI, M-TMSI, GUTI or the like each of which being created on the basis of the IMSI. In the following, just for illustration it is referred to S-TMSI without limiting the present disclosure thereto.

[0145] In Step 1 of Fig. 6, the UE being in RRC IDLE mode and CM IDLE mode for a USIM (in the following USIM-A).

[0146] In step 2 of Fig. 6, the network determines at least one possible paging cause that can be sent from the network to the UE, e.g. when the network initiates downlink data towards the UE when the UE is an RRC IDLE mode for its USIM-A.

[0147] In step 3 of Fig. 6, the network configures at least one paging identifier for the at least one possible paging cause. Following the framework of Fig. 6, such a paging identifier may be a S-TMSI.

[0148] According to Fig. 6, the AMF configures the S-TMSI(s).

[0149] The S-TMSI may be configured such that they have corresponding bits, for example the last 10 bits. This allows that the IMSI value used for paging occasions can be used for all S-TMSIs (e.g. two S-TMSIs).

[0150] S-TMSI(s) may be defined for each of said above at least one possible paging cause towards the UE (i.e. one S- TMSI for one indicated possible paging cause), and/or a group of said above at least one possible paging cause towards the UE (i.e. an S- TMSI for more than one indicated possible paging causes), and/or for all said above at least one possible paging cause towards the UE (i.e. one S- TMSI for all indicated possible paging causes).

[0151] In other words, the network creates a mapping of S-TMSI(s) to paging cause(s). in cases, where the network has provided respective priorities and/or priority orders, the mapping also maps S-TMSI(s) to priority(ies).

[0152] Here and throughout the present disclosure a response or reply to paging involving an S-TMSI means that the UE, for the related USIM, establishes a communication link to the network by means of which communication link the UE can send data and/or control information to the network. Such an operational mode is also referred to as active operational mode. For example, in the framework of Fig. 6, such a communication may be RRCSetupRe- quest message.

[0153] Here and throughout the present disclosure UE not responding or replying to an S- TMSI means that the UE, at least for the related USIM, does not establishes a communication link to the network by means of which communication link the UE can send data and/or control information to the network, but maintains the operational mode in which the UE receives paging messages without parallel ongoing communication link. Such operational modes are also referred to inactive or idle operational modes. For example, in the framework of Fig. 6, such an operational mode to be maintained may be RRC IDLE mode for USIM-A. In such cases, the UE maintains the inactive or idle operational mode and informs the network that it has received the paging message but that it remains inactive or idle.

[0154] Two S-TMSIs may be used, wherein a first S-TMSI can be considered to indicate a first group of one or more paging causes and a second S-TMSI can be considered to indicate a second group of one or more paging causes. For example, the first group may cover one or more paging causes having a high(er) priority, while the second group may cover one or more paging causes having a low(er) priority. Groups of paging causes may be (also) defined with respect to, e.g. an associated service, like voice/VoIP, IMS, other Data, with respect to which the reaction of the UE may differ.

[0155] Also more than two S-TMSIs may be used, to which cases the above observations with respect to more than two S-TMSIs correspondingly apply to. [0156] In step 4 of Fig. 6, the mapping information is provided to the UE. As a result, the UE gets information which S-TMSI is associated to which possible paging cause(s) and, if applicable priority(ies). According to Fig. 6, this accomplished by the AMF by sending a NAS message in which the S-TMSI is included. For example, the network may use a NAS message sent in response to an NAS from the UE, e.g. a tracking area update response, an attach response or registration response. Also, a GUTI-Reallocation-Request message may be used to inform the UE about the S-TMSI.

[0157] In step 5 of Fig. 6, the network sends a paging message to the UE. If the associated paging cause is a paging to which a/the S-TMSI is mapped, the network also provides the S-TMSI towards the UE. According to Fig. 6, the paging message is forwarded to the UE from the AMF by sending a NAS message in which the S-TMSI is included. For example, the network may use a NAS message sent in response to an NAS from the UE, e.g. a tracking area update response, an attach response or registration response. Also, a GUTI-Reallocation- Request message may be used to inform the UE about the S-TMSI.

[0158] In step 6 of Fig. 6, the UE receives such a paging message (i.e. one having an S- TMSI of the mapping information), on the basis of which and, particularly, on the basis of the received S-TMSI, the UE may determine which paging cause is associated thereto.

[0159] Then, it can be decided whether the UE, with respect to USIM-A, leaves the RRC IDLE mode and enters RRC CONNECTED mode, or remains in the RRC IDLE mode for USIM-A.

[0160] Depending on the paging cause, the UE may return an indication to the network, which indication informing the network that the UE has received the paging, but cannot react to the paging as expected by the network. This is illustrated by step 7 of Fig. 6. Following Fig. 6, the UE may send a 5G BUSY indication to the AMF.

[0161] Such indication from the UE to the network may include the received paging identifier (e.g. S-TMSI) or an alternative S-TMSI instead of the identifier used in the paging message. This use of an alternative identifier for busy indication also avoids any attacker UE which receives the paging identifier using the same to send BUSY indication on behalf of the valid UE. The above observations with respect to an identifier indicating the paging cause associated to the received paging message returned to the network apply here correspondingly. [0162] Fig. 7 illustrates a method of operating a communication user equipment, the user equipment being capable of supporting a first network subscription and a second network subscription. In Fig. 7, the step numbers have the extension "UE" to indicated that they relate to the user equipment side.

[0163] In step 1 UE, the user equipment UE receives mapping information indicating mapping of at least one paging identifier I-RNTI, S-TMSI and at least one paging cause.

[0164] In step 2 UE, the user equipment UE is operated in an inactive or idle operational mode with respect to the first network subscription and in RRC connected mode with respect to the second communication network.

[0165] In step 3 UE, the user equipment UE monitors for a paging message from the first communication network, the paging message including at least one of said at least one paging identifier I-RNTI, S-TMSI.

[0166] In step 4 UE, the user equipment UE determines, on the basis of the mapping information, the paging cause indicated by said at least one of said at least one paging identifiers I-RNTI, S-TMSI in the paging message.

[0167] In Step 5 UE, the user equipment UE makes a decision, namely one according to step 6a UE and/or one according to step 6b UE.

[0168] According to step 6a UE, the user equipment UE decides to change from the inactive or idle operational mode of the first network subscription to an active operational mode of the first network subscription. Then, it is proceed to step 7 UE.

[0169] According to step 6b UE, the user equipment UE decides to maintain the inactive or idle operational mode of the first network subscription, and remain therein, on the basis of the determined paging cause. Then, it is proceed to step 7 UE.

[0170] According to step 7 UE, the UE sends a response - that depends from the decision of step 6a UE or 6b UE - to the paging request to the first communication network.

[0171] In the case the decision of step 6b UE is that the UE remains in the inactive or idle operational mode, the response may be, or include a busy indication that inform the first communication network of step 6b UE decision. [0172] Fig. 8 illustrates a method of operating a communication network capable of supporting a user equipment UE, the user equipment UE being capable of supporting a first network subscription USIM-A and a second network subscription USIM-B, the first network subscription being associated to the communication network. In Fig. 8, the step numbers have the extension "NW" to indicated that they relate to the network side.

[0173] In step 1 NW, the network provides, to the user equipment UE, mapping information indicating mapping of at least one paging identifier I-RNTI, S-TMSI and at least one paging cause.

[0174] In step 2 NW, the network sends a paging message from the communication network to the user equipment UE if being operated in an inactive or idle operational mode with respect to the first network subscription, the paging message including at least one of said at least one paging identifier I-RNTI, S-TMSI.

[0175] In step 3 NW, the network receives a response from the user equipment UE to the paging message.

[0176] According to step 4a NW, the network receives a response from the user equipment UE to the paging message that the user equipment UE changes from the inactive or idle operational mode of the first network subscription to an active operational mode of the first network subscription.

[0177] According to step 4b NW, the network receives a response from the user equipment UE to the paging message that the user equipment UE has received the paging message and remains in the inactive or idle operational mode of the first network subscription.

[0178] The response of step 4b may be or may include a busy indication which indicates that the paging message has been received and the inactive or idle operational mode is continued.

[0179] The subject matter described herein may be embodied in systems, apparatus, methods, and/or articles depending on the desired configuration. For example, the user equipment (or one or more components therein) and/or the processes described herein can be implemented using one or more of the following: a processor executing program code, an appli- cation-specific integrated circuit (ASIC), a digital signal processor (DSP), an embedded processor, a field programmable gate array (FPGA), and/or combinations thereof. These various implementations may include implementation in one or more computer programs that are executable and/or interpretable on a programmable system including at least one programmable processor, which may be special or general purpose, coupled to receive data and instructions from, and to transmit data and instructions to, a storage system, at least one input device, and at least one output device. These computer programs (also known as programs, software, software applications, applications, components, program code, or code) include machine instructions for a programmable processor, and may be implemented in a high-level procedural and/or object-oriented programming language, and/or in assembly/machine language. As used herein, the term "computer-readable medium" refers to any computer program product, machine-readable medium, computer-readable storage medium, apparatus and/or device (for example, magnetic discs, optical disks, memory, Programmable Logic Devices (PLDs)) used to provide machine instructions and/or data to a programmable processor, including a machine- readable medium that receives machine instructions. Similarly, systems are also described herein that may include a processor and a memory coupled to the processor. The memory may include one or more programs that cause the processor to perform one or more of the operations described herein.

[0180] Although a few variations have been described in detail above, other modifications or additions are possible. In particular, further features and/or variations may be provided in addition to those set forth herein. Moreover, the implementations described above may be directed to various combinations and sub-combinations of the disclosed features and/or combinations and sub-combinations of several further features disclosed above. Other embodiments may be within the scope of the following claims.

[0181] If desired, the different functions discussed herein may be performed in a different order and/or concurrently with each other. Furthermore, if desired, one or more of the abovedescribed functions may be optional or may be combined. Although various aspects of some of the embodiments are set out in the independent claims, other aspects of some of the embodiments comprise other combinations of features from the described embodiments and/or the dependent claims with the features of the independent claims, and not solely the combinations explicitly set out in the claims. It is also noted herein that while the above describes example embodiments, these descriptions should not be viewed in a limiting sense. Rather, there are several variations and modifications that may be made without departing from the scope of some of the embodiments as defined in the appended claims. Other embodiments may be within the scope of the following claims. The term "based on" includes "based on at least". The use of the phase "such as" means "such as for example" unless otherwise indicated.

Claims

38 WE CLAIM:

1. A method of operating a communication user equipment (UE), the user equipment (UE) being capable of supporting a first network subscription (USIM; USIM-A) and a second network subscription (USIM, USIM-B), the method comprising:

- receiving, at the user equipment (UE), mapping information indicating mapping of at least one paging identifier (I-RNTI, S-TMSI) to at least one paging cause;

- operating the user equipment (UE) in an inactive or idle operational mode with respect to the first network subscription;

- monitoring, by the user equipment (UE), for a paging message from the first communication network, the paging message including at least one of said at least one paging identifiers (I- RNTI, S-TMSI);

- determining, on the basis of the mapping information, a paging cause indicated by the said at least one paging identifier (I-RNTI, S-TMSI) in the paging message,

- deciding on the basis of the determined paging cause whether

2. A method according to claim 1, comprising

- sending a busy indication in the response to the paging message from the user equipment (UE) to the first communication network in the case it is decided to maintain the inactive or idle operational with respect to the first network subscription, the busy indication informing the first communication network that the user equipment (UE) remains the inactive or idle operational with respect to the first network subscription.

3. A method according to one of the preceding claims, comprising

4. A method according to one of the preceding claims, wherein

- the mapping information is received in encrypted or protected manner.

5. User equipment (UE) comprising 39

- at least one processor; and

- at least one memory including computer program code;

- the at least one memory and the computer code configured to, with the at least one processor, cause the user equipment (UE) at least to perform:

- support a first network subscription (USIM; USIM-A) and a second network subscription (USIM, USIM-B),

- receive, at the user equipment (UE), mapping information indicating mapping of at least one paging identifier (I-RNTI, S-TMSI) and at least one paging cause;

- operate the user equipment (UE) in an inactive or idle operational mode with respect to the first network subscription,

- monitor, by the user equipment (UE), for a paging message from the first communication network, the paging message including at least one of said at least one paging identifier (I- RNTI, S-TMSI);

- determine, on the basis of the mapping information, a paging cause indicated by the said at least one paging identifier (I-RNTI, S-TMSI) in the paging message,

- decide on the basis of the determined paging cause whether

- send a response to the paging message, based on the said decision, to the first communication network

6. User equipment (UE) according to claim 5, wherein the at least one memory and the computer code configured to, with the at least one processor, cause the user equipment (UE) at least to perform:

- to send a busy indication in the response to the paging message from the user equipment (UE) to the first communication network in the case it is decided to maintain the inactive or idle operational with respect to the first network subscription, the busy indication informing the first communication network that the user equipment (UE) remains the inactive or idle operational with respect to the first network subscription.

7. User equipment (UE) according to claim 5 or 6, wherein the at least one memory and the computer code configured to, with the at least one processor, cause the user equipment (UE) at least to perform:

- send, if it is determined to maintain the inactive or idle operational mode of the first network subscription, an identifier to the network, the indication indicating the determined paging cause. 40

8. User equipment (UE) according to one of the claims 5-7, wherein

- the mapping information is received in encrypted or protected manner.

9. A method of operating a communication network capable of supporting a user equipment (UE), the user equipment (UE) being capable of supporting a first network subscription (USIM; USIM-A) and a second network subscription (USIM, USIM-B), the first network subscription being associate to the communication network, the method comprising:

- providing, to the user equipment (UE), mapping information indicating mapping of at least one paging identifier (I-RNTI, S-TMSI) to at least one paging cause;

- sending a paging message from the communication network to the user equipment (UE) if being operated in an inactive or idle operational mode with respect to the first network subscription, the paging message including at least one of said at least one paging identifier (I- RNTI, S-TMSI);

- receiving, at the communication network, a response from the user equipment (UE) to the paging message.

10. A method according to claim 9, comprising

- receiving a busy indication in the response to the paging message from the user equipment (UE), the busy indication informing the network that the user equipment (UE) remains in the inactive or idle operational mode of the first network subscription.

11. A method according to claim 9 or 10, comprising

12. A method according to one of the claims 9 to 11, wherein

- the mapping information is provided in encrypted or protected manner.

13. Communication network

- at least one processor; and

- at least one memory including computer program code;

- the at least one memory and the computer code configured to, with the at least one processor, cause the communication network at least to perform: - support a user equipment (UE), the user equipment (UE) being capable of supporting a first network subscription (USIM; USIM-A) and a second network subscription (USIM, USIM-B), the first network subscription being associate to the communication network;

- provide, to the user equipment (UE), mapping information indicating mapping of at least one paging identifier (I-RNTI, S-TMSI) and at least one paging cause;

- send a paging message from the communication network to the user equipment (UE) being operated in an inactive or idle operational mode with respect to the first network subscription , the paging message including at least one of said at least one paging identifier (I-RNTI, S- TMSI);

- receive, at the communication network, a response from the user equipment (UE) to the paging message.

14. Communication network according to claim 13, wherein the at least one memory and the computer code configured to, with the at least one processor, cause the communication network at least to perform:

- receive a busy indication in the response to the paging message from the user equipment (UE), the busy indication informing the network that the user equipment (UE) remains in the inactive or idle operational mode of the first network subscription.

15. Communication network according to claim 13 or 14, wherein the at least one memory and the computer code configured to, with the at least one processor, cause the communication network at least to perform:

- receive an identifier from the user equipment (UE), the identifier indicating a paging cause to which said at least one of said at least one paging identifier (I-RNTI, S-TMSI) is mapped to.

16. Communication network according to one of claims 13 to 15, wherein the at least one memory and the computer code configured to, with the at least one processor, cause the communication network at least to perform:

- provide the mapping information in encrypted or protected manner.

17. A computer program comprising instructions stored thereon for carrying out

- the method of one of the claims 1 to 4, or

- the method of one of the claims 9 to 12.