Patent ID: 12245183

DETAILED DESCRIPTION

The embodiments herein and the various features and advantageous details thereof are explained more fully with reference to the non-limiting embodiments that are illustrated in the accompanying drawings and detailed in the following description. Descriptions of well-known components and processing techniques are omitted so as to not unnecessarily obscure the embodiments herein. Also, the various embodiments described herein are not necessarily mutually exclusive, as some embodiments can be combined with one or more other embodiments to form new embodiments. The term “or” as used herein, refers to a non-exclusive or, unless otherwise indicated. The examples used herein are intended merely to facilitate an understanding of ways in which the embodiments herein can be practiced and to further enable those skilled in the art to practice the embodiments herein. Accordingly, the examples should not be construed as limiting the scope of the embodiments herein.

As is traditional in the field, embodiments may be described and illustrated in terms of blocks which carry out a described function or functions. These blocks, which may be referred to herein as units or modules or the like, are physically implemented by analog or digital circuits such as logic gates, integrated circuits, microprocessors, microcontrollers, memory circuits, passive electronic components, active electronic components, optical components, hardwired circuits, or the like, and may optionally be driven by firmware and software. The circuits may, for example, be embodied in one or more semiconductor chips, or on substrate supports such as printed circuit boards and the like. The circuits constituting a block may be implemented by dedicated hardware, or by a processor (e.g., one or more programmed microprocessors and associated circuitry), or by a combination of dedicated hardware to perform some functions of the block and a processor to perform other functions of the block. Each block of the embodiments may be physically separated into two or more interacting and discrete blocks without departing from the scope of the invention. Likewise, the blocks of the embodiments may be physically combined into more complex blocks without departing from the scope of the invention.

The accompanying drawings are used to help easily understand various technical features and it should be understood that the embodiments presented herein are not limited by the accompanying drawings. As such, the present disclosure should be construed to extend to any alterations, equivalents and substitutes in addition to those which are particularly set out in the accompanying drawings. Although the terms first, second, etc. may be used herein to describe various elements, these elements should not be limited by these terms. These terms are generally only used to distinguish one element from another.

The terms “paring” and “binding” mean the same and used interchangeably throughout this document. The terms “belong” and “hosted” mean the same and used interchangeably throughout this document. The terms “first SIM” and “USIM-1” mean the same and used interchangeably throughout this document. The terms “second SIM” and “USIM-2” mean the same and used interchangeably throughout this document. The term SIM and USIM mean the same and used interchangeably throughout the document.

Accordingly, the embodiments herein provide a method for binding a plurality of subscriber identity modules (SIMs) associated with a user equipment (UE) to optimize network resources in a wireless network. The method includes registering multiple SIMs with a network entity in the wireless network, receiving Non-access stratum (NAS) security contexts and temporary identifiers associated with the multiple SIMS from the network entity over NAS connections of the multiple SIMs. Further, the method includes determining a Public Land Mobile Network (PLMN) associated with the registered multiple SIMs, generating a message authentication code using the NAS security contexts associated with the multiple SIMs, sending a message over the NAS connections of the multiple SIMS. Further, the method includes verifying, by the network entity, the message and paring multiple SIM based on the verification result.

Referring now to the drawings, and more particularly toFIGS.1through8, there are shown preferred embodiments.

FIG.1illustrates a block diagram of a user equipment (UE) (100) for binding a plurality of subscriber identity modules (SIMS) (150) associated with the UE (100) to optimize network resources in a wireless network, according to the embodiments as disclosed herein. In an embodiment, the UE (100) includes a memory (110), a processor (120), a communicator (130), a display (140), SIMS (150), a service request message configuration controller (160), and a code generator (170).

The memory (110) also stores instructions to be executed by the processor (120). The memory (110) may include non-volatile storage elements. Examples of such non-volatile storage elements may include magnetic hard discs, optical discs, floppy discs, flash memories, or forms of electrically programmable memories (EPROM) or electrically erasable and programmable (EEPROM) memories. In addition, the memory (110) may, in some examples, be considered a non-transitory storage medium. The term “non-transitory” may indicate that the storage medium is not embodied in a carrier wave or a propagated signal. However, the term “non-transitory” should not be interpreted that the memory (110) is non-movable. In some examples, the memory (110) can be configured to store larger amounts of information than the memory. In certain examples, a non-transitory storage medium may store data that can, over time, change (e.g., in Random Access Memory (RAM) or cache). In an embodiment, the memory (110) can be an internal storage unit or it can be an external storage unit of the electronic device100, a cloud storage, or any other type of external storage.

The processor (120) communicates with the memory (110), the communicator (130), the display (140), the SIM (150), the service request message configuration controller (160), and the code generator (170). The processor (120) is configured to execute instructions stored in the memory (110) and to perform various processes. The communicator (130) is configured for communicating internally between internal hardware components and with external devices via one or more networks.

In an embodiment, the service request message configuration controller (160) registers a first SIM (150a) from the plurality of SIMS (150) with the network entity (200) in the wireless network. Further, the service request message configuration controller (160) registers a second SIM (150b) from the plurality of SIMS (150) with the network entity (200) in the wireless network. Further, the service request message configuration controller (160) receives a Non-access stratum (NAS) security context and a temporary identifier (i.e. 5G GUTI-1) associated with the first SIM (150a) from the network entity (200) over a NAS connection of the first SIM (150a) in response to the successful registration of the first SIM (150a) with the network entity (200). Further, the service request message configuration controller (160) receives a NAS security context and a temporary identifier (i.e. 5G GUTI-2) associated with the second SIM (150b) from the network entity (200) over a NAS connection of the second SIM (150b) in response to the successful registration of the second SIM (150b) with the network entity (200).

Further, the service request message configuration controller (160) determines whether a message sends over at least one of the NAS connection of the first SIM (150a) and the NAS connection of the second SIM (150b). The message indicates that the first SIM (150a) and the second SIM (150b) are located on the same UE (100).

Further, the code generator (170) generates the message authentication code using the NAS security context associated with the first SIM (150a) when the UE (100) sends the message over the NAS connection of the second SIM (150b). Further, the service request message configuration controller (160) sends the message authentication code with the NAS security context associated with the first SIM (150a)

Further, the code generator (170) generates the message authentication code using the NAS security context associated with the second SIM (150b) when the UE (100) sends the message over the NAS connection of the first SIM (150a). Further, the service request message configuration controller (160) sends the message authentication code with the NAS security context associated with the second SIM (150b).

Further, the service request message configuration controller (160) receives a request message from the network entity (200). The request message comprises the temporary identifier of the at least one of the first SIM (150a), and the second SIM (150b). Further, the service request message configuration controller (160) determines whether the temporary identifier received by the UE (100) matches with the temporary identifier received during the registration procedure. Further, the service request message configuration controller (160) sends a verification success message to the network entity (200) in response to determining that the temporary identifier received by the UE (100) matches with the temporary identifier received during the registration procedure. Further, the service request message configuration controller (160) sends a verification failure message to the network entity in response to determining that the temporary identifier received by the network entity (200) does not match with the temporary identifier received during the registration procedure.

Further, the service request message configuration controller (160) selects the first SIM (150a) selected PLMN for the second SIM (150b), if the first SIM (150a) selected PLMN is listed in the preferred PLMN list of secondary PLMN. Further, the service request message configuration controller (160) selects the PLMN if the PLMN is listed in the preferred PLMN list of both SIMs (150aand150b). Further, the service request message configuration controller (160) selects the PLMN if Home Public Land Mobile Network (HPLMN) of any one of the SIMs (150aor150b) and selects the same PLMN for other SIMs (150) also if HPLMN of other SIMS (150) are not available.

Although theFIG.1shows various hardware components of the UE (100) but it is to be understood that other embodiments are not limited thereon. In other embodiments, the UE (100) may include less or more number of components. Further, the labels or names of the components are used only for illustrative purpose and does not limit the scope of the invention. One or more components can be combined together to perform same or substantially similar function to bind the plurality of SIMs (150) associated with the UE (100) to optimize network resources in the wireless network.

FIG.2illustrates a block diagram of the network entity (200) for binding the plurality of SIMs (150) associated with the UE (100) to optimize network resources in the wireless network, according to the embodiments as disclosed herein. In an embodiment, the network entity (200) includes a memory (210), a processor (220), a communicator (230), a service response message configuration controller (240), and a code generator (250). In an embodiment, the network entity (200) comprises a Next-Generation Radio Access Network (NG-RAN) (200a), an Access and Mobility Management Function (AMF)/Security Anchor Function (SEAF) (200b), a Unified Data Management (UDM)-1 (200c), and a UDM-2 (200d) (not shown in theFIG.2).

The memory (210) also stores instructions to be executed by the processor (220). The memory (210) may include non-volatile storage elements. Examples of such non-volatile storage elements may include magnetic hard discs, optical discs, floppy discs, flash memories, or forms of electrically programmable memories (EPROM) or electrically erasable and programmable (EEPROM) memories. In addition, the memory (210) may, in some examples, be considered a non-transitory storage medium. The term “non-transitory” may indicate that the storage medium is not embodied in a carrier wave or a propagated signal. However, the term “non-transitory” should not be interpreted that the memory (210) is non-movable. In some examples, the memory (210) can be configured to store larger amounts of information than the memory. In certain examples, a non-transitory storage medium may store data that can, over time, change (e.g., in Random Access Memory (RAM) or cache). In an embodiment, the memory (210) can be an internal storage unit or it can be an external storage unit of the electronic device100, a cloud storage, or any other type of external storage.

The processor (220) communicates with the memory (210), the communicator (230), the service response message configuration controller (240), and the code generator (250). The processor (220) is configured to execute instructions stored in the memory (210) and to perform various processes. The communicator (230) is configured for communicating internally between internal hardware components and with external devices via one or more networks.

In an embodiment, the service response message configuration controller (240) allocates the NAS security context and the temporary identifier associated with the first SIM (150a) to the first SIM (150a) over the NAS connection of the first SIM (150a). Further, the service response message configuration controller (240) allocates the NAS security context and the temporary identifier associated with the second SIM (150b) to the second SIM (150b) over the NAS connection of the second SIM (150b). Further, the service response message configuration controller (240) receives the message over the at least one of the NAS connection of the first SIM (150a) and the NAS connection of the second SIM (150b).

The code generator (250) generates a message authentication code corresponding to the received NAS security context. Further, the service response message configuration controller (240) determines whether the UE (100) generated message authentication code is matched with the message authentication code generated by the code generator (250).

Further, the service response message configuration controller (240) sends an accept message to the UE (100) in response to determining that the UE (100) generated message authentication code is matches with the message authentication code generated by the code generator (250), the accept message indicates that the first SIM (150a) and the second SIM (150b) are located on the same UE (100). Further, the service response message configuration controller (240) pairs the first SIM (150a) with the second SIM (150b) to optimize network resources in the wireless network

Further, the service response message configuration controller (240) sends a reject message to the UE (100) in response to determining that the UE (100) generated message authentication code does not match with the message authentication code generated by the code generator (250), the reject message indicates that the first SIM (150a) and the second SIM (150b) are not located on the same UE (100).

Further, the service response message configuration controller (240) receives the verification success message from the UE (100) in response to determining that the temporary identifier sends by the network entity (200) matches with the temporary identifier received during the registration procedure. Further, the service response message configuration controller (240) sends an accept message to the UE (100) and pairing the first SIM (150a) with the second SIM (150b) to optimize network resources in the wireless network in response to receiving the verification success message.

Further, the service response message configuration controller (240) receives the verification failure message from the UE (100) in response to determining that the temporary identifier sends by the network entity (200) does not match with the temporary identifier received during the registration procedure. Further, the service response message configuration controller (240) sends a reject message to the UE (100) in response to receiving the verification failure message.

Further, the service response message configuration controller (240) receives device Identification from a home network. Such device identification information received for authentication of multiple SIMs (150) may be used by serving network's AMF (200b) to identify SIMS (150aand150b) belonging to the same UE (100) and use such information for multi-SIM optimizations. Further, the service response message configuration controller (240) performs multi USIM optimizations based on an intent indication from the UE (100). Further, the service response message configuration controller (240) identifies SIMS (150aand150b) belonging to the same UE (100) without any intent indication received from the UE (100). Further, the service response message configuration controller (240) obtains IMEIs/PEIs belonging to the same UE (100) and maps the SUPIs associated with the IMEIs of the UE (100) for multi-SIM optimizations.

Although theFIG.2shows various hardware components of the network entity (200) but it is to be understood that other embodiments are not limited thereon. In other embodiments, the network entity (200) may include less or more number of components. Further, the labels or names of the components are used only for illustrative purpose and does not limit the scope of the invention. One or more components can be combined together to perform same or substantially similar function to bind the plurality of SIMs (150) associated with the UE (100) to optimize network resources in the wireless network.

FIG.3AtoFIG.3Cillustrate a flow diagram (300) illustrating various operations for binding the plurality of SIMs (150) associated with the UE (100) to optimize network resources in the wireless network, according to the embodiments as disclosed herein.

At302, the method includes registering, by the UE (100), the first SIM (150a) from the plurality of SIMs (150) with the network entity (200) in the wireless network. At304, the method includes registering, by the UE (100), the second SIM (150b) from the plurality of SIMs (150) with the network entity (200) in the wireless network. At306, the method includes receiving, by the UE (100), the NAS security context and the temporary identifier (i.e. 5G GUTI-1) associated with the first SIM (150a) from the network entity (200) over the NAS connection of the first SIM (150a) in response to the successful registration of the first SIM (150a) with the network entity (200).

At308, the method includes receiving, by the UE (100), the NAS security context and the temporary identifier (i.e. 5G GUTI-2) associated with the second SIM (150b) from the network entity (200) over the NAS connection of the second SIM (150b) in response to the successful registration of the second SIM (150b) with the network entity (200). At310, the method includes determining, by the UE (100), that the first SIM (150a) and the second SIM (150b) are registered on same the PLMN. At312, the method includes sending a message through one of the NAS connection of the first SIM (150a) and the NAS connection of the second SIM (150b), determining that the message sends over at least one of the NAS connection of the first SIM (150a) and the NAS connection of the second SIM (150b). The message indicates that the first SIM (150a) and the second SIM (150b) are located on the same UE (100).

At314a, the method includes generating, by the UE (100), the message authentication code using the NAS security context associated with the first SIM (150a) when the UE (100) sending the message over the NAS connection of the second SIM (150b). At316a, the method includes sending, by the UE (100), the message authentication code with the NAS security context associated with the first SIM (150a). At314b, the method includes generating, by the UE (100), the message authentication code using the NAS security context associated with the second SIM (150b) when the UE (100) sending the message over the NAS connection of the first SIM (150a). At316b, the method includes sending, by the UE (100), the message authentication code with the NAS security associated with the second SIM (150b).

At318, the method includes receiving, by the network entity (200), the message over the at least one of the NAS connection of the first SIM (150a) and the NAS connection of the second SIM (150b). At320, the method includes generating, by the network entity (200), the message authentication code corresponding to the received NAS security context. At322, the method includes determining, by the network entity (200), whether the UE (100) generated message authentication code matches the message authentication code generated by the network entity (200).

At324a, the method includes sending, by the network entity, the accept message to the UE (100) in response to determining that the UE (100) generated message authentication code matches the message authentication code generated by the network entity (200). At326a, the method includes indicating, by the network entity (200), that the first SIM (150a) and the second SIM (150b) are located on the same UE (100). At328a, the method includes pairing, by the network entity, the first SIM (150a) with the second SIM (150b) to optimize network resources in the wireless network. At324b, the method includes sending, by the network entity (200), the reject message to the UE (100) in response to determining that the UE (100) generated message authentication code does not match the message authentication code generated by the network entity (200). At326b, indicating, by the network entity (200), that the first SIM (150a) and the second SIM (150b) are located on different UEs. At328b, no pairing, by the network entity (200), between the first SIM (150a) with the second SIM (150b).

FIG.4AtoFIG.4Billustrate an example sequential flow diagram illustrating that the network entity (200) performing a verification procedure to determine whether the first SIM (150a) and the second SIM (150b) are associated with the same UE (100) or different UEs based on an indication message received from the UE (100), according to an embodiment as disclosed herein.

At402-404, the UE (100) registers to the network entity (200) for the first SIM (150a) (i.e. USIM-1) and the second SIM (150b) (i.e. USIM-2) independently as per procedures specified in 3GPP TS 23.501 and TS 33.501. After successful registration to the network entity (200), NAS security context is established and a temporary identifier (i.e. 5G GUTI) assigned to the UE (100) for the USIM-1 (150a) and the USIM-2 (150b) independently by the network entity (200) (i.e. serving network).

At406-408, when the USIM-1 (150a) and the USIM-2 (150b) register to the same network (PLMN) independently, then the UE (200) may decide to indicate to the network entity (200) that USIM-1 (150a) (GUTI-1) and USIM-2 (150b) (GUTI 2) are located on the same UE (200) and ready for any multi-SIM optimizations from the network entity (200). The UE (200) may send the indication to the network entity (200) over the NAS connection belonging to the USIM-1 (150a) or the USIM-2 (150b). If the UE (100) chooses to send the indication over USIM-2 (150b) NAS connection, then the UE (200) generates a message authentication code (MAC_col) using NAS (N1) security context of USIM-1 (150a). Further information on the authentication code of the message is given in theFIG.5.

At410, the UE (100) sends the MAC_col and indication message (5G GUTI of USIM-1 (150a) (GUTI 1), Random number Nonce) to the network entity (200) by one of a New NAS message, a Registration Request message, a Registration Accept ACK message and a NAS Security Mode Command (SMC) complete message. At412, the AMF (200b) receives the MAC_COL and corresponding message with 5G-GUTI (GUTI-1) in the NAS message from the UE (100), then the AMF (200b) identifies corresponding NAS security context for 5G-GUTI (GUTI-1) and using the NAS security context, calculates MAC_COL same as the UE (100).

At414, if MAC_COL received from the UE (100) and generated by the AMF (200b) match then the AMF (200b) considers that the USIM-1 (150a) and the USIM-2 (150b) are allocated on the same UE (100) and shall consider this information for any network controlled optimization, like paging resources. At416-418, the AMF (200b) also send the indication of this information to the UE (100) in a response message (e.g. accept message, reject message). Further, the network entity (200)'s AMF (200b) may perform one of not send the result of verification to the UE (100), send the result of verification to the UE (100) in one of a New NAS message, a Registration Accept message, a NAS SMC message.

FIG.5illustrates an authentication code generator (170and250) to verify whether the first SIM (150a) and the second SIM (150b) are associated with the same UE (100) or different UEs, according to an embodiment as disclosed herein.

Example of the authentication code generator (170&250) when the UE (100) chooses to send the indication over the USIM-2 (150b) NAS connection. The input for the code generator (170) are KEY (KNASint corresponding to USIM-1 (150a)'s NAS security context), 5G GUTI of USIM-1 (150a) (GUTI-1), random value nonce, MAC_count, and uplink NAS Count of NAS COUNT pair corresponding to USIM-1 (150a)'s NAS security context.

MAC_COUNT is a counter used for calculation of MAC_col and is incremented by the UE (100) after every MAC_col calculation and by the AMF (200b) after MAC_col verification. The start value of MAC_COUNT is issued to the UE (100) by the AMF (200b) after a successful registration procedure of the UE (100) with the network entity (200). The UE (100) increments the uplink NAS Count value after MAC_col calculation.

The UE (100) sends the MAC_col and the indication message (5G GUTI of USIM-1 (150a) (GUTI 1), Random number Nonce) in the NAS message to the AMF (200b) along with other appropriate information. Upon receipt of such message from the UE (100), if there is a MAC_col and an indication message in initial registration message from the UE (100), then the AMF (200b) takes the message as an indication from USIM-2 (150b) that USIM-2 (150b) is located with another USIM on the UE (100). In such a case, the AMF (200b) verifies the MAC_col. The AMF calculates the MAC_col like the UE (100) by the code generator (250).

Inputs of the code generator (250) are key for MAC_col calculation is identified based on 5G GUTI (GUTI-1) in an indication message from the UE (100). Upon successful verification of MAC_col, the AMF (200b) considers that USIM-1 (150a) (NAS context identifier 5G GUTI) and USIM-2 (150b) (NAS context identifier 5G GUTI) are located on the same UE (100) and uses the information for any network-controlled optimizations for dual SIM. AMF also sends the result of the verification to the UE in the NAS response message. After calculation of MAC_col, serving network's AMF (200b) updates/increments the MAC_COUNT and the uplink NAS Count in NAS COUNT Pair for the UE (100) (USIM-1 (150a)).

In multi-USIM (150) scenario, the UE (100) may send MAC_col and indication message of each USIM (150) in the NAS message to the network entity (200). The AMF (200b) will consider for network controlled optimizations if the verification MAC_col of all USIMs (150) are successful.

FIG.6AtoFIG.6Billustrate an example sequential flow diagram illustrating that the network entity (200) performing a verification procedure to determine whether the first SIM (150a) and the second SIM (150b) are associated with the same UE (100) or different UEs during a registration procedure, according to an embodiment as disclosed herein.

At602, the UE (100) registers to the network entity (200) for the USIM-1 (150a) as per procedures specified in 3GPP TS 23.501 and TS 33.501. After successful registration to the network entity (200), NAS security context is established and a temporary identifier (i.e. 5G GUTI) assigned to the UE (100) for the USIM-1 (150a) by the network entity (200) (i.e. serving network).

At604, when the UE (100) wants to register to the network entity (200) for the USIM-2 (150b), selects the same PLMN as the USIM-1 (150a) as per PLMN selection policy for the USIM-2 (150b), then the UE (100) generates a message authentication code (MAC_col) by the code generator (170) (ReferFIG.5). At606, the inputs to the code generator (170) are KEY (Knasint corresponding to USIM-1 (150a)'s NAS security context), 5G GUTI of USIM-1 (150a) (GUTI-1), random value nonce, MAC_count, and uplink NAS Count of NAS COUNT pair corresponding to USIM-1 (150a)'s NAS security context.

MAC_COUNT is a counter used for calculation of MAC_col and is incremented by the UE (100) after every MAC_col calculation and by the AMF (200b) after MAC_col verification. The start value of MAC_COUNT is issued to the UE (100) by the AMF (200b) after a successful registration procedure of the UE (100) with the network entity (200). The UE (100) increments the uplink NAS Count value after MAC_col calculation.

At608, the UE (100) sends the MAC_col and the indication message (5G GUTI of USIM-1 (150a) (GUTI 1), Random number Nonce) in the registration request to the AMF (200b) for the USIM-2 (150b) along with other appropriate information as per 3GPP specification TS 23.501 and TS 33.501. At610, upon receipt of the registration request from the UE (100), the AMF (200b) proceeds with registration procedure as specified in TS 23.501 and TS 33.501.

At612, if the MAC_col and an indication message in initial registration message from the UE (100), then the AMF (200b) takes the message as an indication from the USIM-2 (150b) that it is located with another USIM on the same UE (100). At614, in such a case, after successful primary authentication of the UE (100) for the USIM-2 (150b) and before Registration accept message to the UE (100), the AMF (200b) verifies the MAC_col. The AMF (200b) calculates the MAC_col like the UE (100) (ReferFIG.5). The input to the code generator (250) are key for MAC_col calculation is identified based on 5G GUTI (GUTI 1) in an indication message from the UE (100).

At616, upon successful verification of the MAC_col, the AMF (200b) considers that USIM-1 (150a) (NAS context identifier 5G GUTI) and USIM-2 (150b) (NAS context identifier 5G GUTI) are located on the same UE (100) and uses the information for any network-controlled optimizations for multi-SIM. At618, the AMF (200b) also sends the result of the verification to the UE (100) in the registration response message. After calculation of MAC_col, the AMF (200b) updates/increments the MAC_COUNT and the uplink NAS Count in NAS COUNT Pair for the UE (100) (USIM-1 (150a)).

In multi-USIM (150) scenario, the UE (100) may send MAC_col and indication message of each USIM (150) in the registration procedure to the network entity (200). The AMF (200b) will consider for network-controlled optimizations if the verification MAC_col of all USIMs (150) are successful.

FIG.7AtoFIG.7Billustrate an example sequential flow diagram illustrating that the network entity (200) performing piggybacks and a verification procedure to determine whether the first SIM (150a) and the second SIM (150b) are associated with the same UE (100) or different UEs based on an indication message received from the UE (100), according to an embodiment as disclosed herein.

At702-704, the UE (100) registers to the network entity (200) for the USIM-1 (150a) and the USIM-2 (150b) independently as per procedures specified in 3GPP TS 23.501 and TS 33.501. After successful registration to the network entity (200), NAS security context is established and a temporary identifier (i.e. 5G GUTI) assigned to the UE (100) for the USIM-1 (150a) and the USIM-2 (150b) independently by the network entity (200) (i.e. serving network).

At706, when the USIM-1 (150a) and the USIM-2 (150b) are camped to the same network (PLMN), then the UE (100) may decide to indicate to the network that USIM-1 (150a) (GUTI 1) and USIM-2 (150b) (GUTI 2) are located on the same UE (100) and ready for any multi-SIM optimizations from the network. At708, the UE (100) may send an indication to the network entity (200) over NAS connection belonging to the USIM-1 (150a) or the USIM-2 (150b).

At710, upon receipt of such an indication message from the UE (100), the AMF (200b) takes the message as an indication from USIM-2 (150b) that it is located with another USIM on the same UE (100). In such a case, the AMF (200b) sends a verification request to the USIM-1 (150a) (GUTI 1) over the USIM-1's NAS connection for verification for USIM-2 (150b) (GUTI 2). At712-714, upon such a request from the AMF (200b), the UE (100) checks if the USIM-1 (150a) and the USIM-2 (150b) are located on the same UE (100), and responds to the AMF (200b) with the verification result.

At716-718, upon on receipt of successful confirmation from the UE (100) (USIM-1 (150a) NAS connection), the AMF (200b) considers that USIM-1 (150a) (NAS context identifier 5G GUTI) and the USIM-2 (150b) (NAS context identifier 5G GUTI) are located on the same UE (100) and uses this information for any network controlled optimizations for multi-SIM (150). At720, the AMF (200b) also sends the result of the verification to the UE (100) (USIM-2 (150b)) in the NAS response message.

In multi-USIM (150) scenario, the UE (100) may send 5G GUTI of each USIM (150) in the indication message over NAS to the network entity (200). The AMF (200b) requests all the USIMs (150) in the indication message, requesting for verification. The AMF (200b) will consider for network-controlled optimizations based on successful verification messages from the requested USIMs (150) by the serving network's AMF (200b).

FIG.8illustrates an example sequential flow diagram illustrating that the network entity (200) performing a verification procedure to determine whether the first SIM (150a) and the second SIM (150b) are associated with the same UE (100) or different UEs based on successful authentication the first SIM (150a) over an N1 signalling connection of the second SIM (150b), according to an embodiment as disclosed herein.

At802, the UE (100) initiates the registration procedure for USIM-1 (150a) and the registration procedure is successfully performed. The 5G NAS security context is established for the USIM-1 (150a) and 5G-GUTI-1 has been assigned. At804, the UE (100) is in 5G Mobility Management (5GMM)-IDLE mode for the USIM-1 (150a) and initiates registration procedure for the USIM-2 (150b). At806, the UE (100) sends the Registration Request message containing 5G-GUTI-1 and SUCI-2 of the USIM-2 (150b). The presence of 5G-GUTI-1 indicates to the network entity (200) to bind the context of the USIM-1 (150a) and the USIM-2 (150b). Alternatively, the UE (100) sends an explicit binding indication to the network entity (200) to bind the USIM-1 (150a) and the USIM-2 (150b). The N1-signaling connection is established between the UE (100) and the AMF (200b) for the USIM-2 (150b).

At808, the network entity (200) performs an authentication procedure for the USIM-2 (150b). The network entity (200) may perform a security mode command procedure for the USIM-2 (150b). At810, after the successful authentication procedure or security mode command procedure, the network entity (200) assigns 5G-GUTI-2 to the USIM-2 (150b), and the registration procedure is performed successfully.

At812, the network entity (200) does not release the N1 signalling connection. The network on the USIM-2 (150b) N1 signalling connection performs one of the following steps:

Performs authentication procedure for the USIM-1 (150a); Or

The network entity (200) requests to the UE (100) to send integrity protected NAS message using the Security context of the USIM-1 (150a). The UE (100) sends a NAS message with integrity protected using the security context of the USIM-1 (150a). The NAS message from the UE (100) may contain any information related to the USIM-1 (150a)'s NAS context or the NAS message from the UE (100) may not contain any information element. The NAS message from the UE (100) and the Serving network′ AMF (200b), may be an existing message or a new NAS message. The NAS message from the UE (100) is NAS protected (NAS-MAC) using the USIM-1 (150a)'s security context as specified in TS 33.501. The network entity (200) verifies if the integrity protection of the received NAS message using the USIM-1 (150a)'s security context is successful or not.

At814, if the procedure i) or ii) in step812has been performed successfully then the network determines that USIM-1 (150a) and the USIM-2 (150b) are present in the same UE (100). The UE (100) binds the USIM-1 (150a) and the USIM-2 (150b) (e.g. NAS context of the USIM-1 (150a) and the USIM-2 (150b)). Further, if the procedure i) or ii) in step812fails then the network entity (200) does not bind the USIM-1 (150a) and the USIM-2 (150b).

In one example, the network entity (200) considers the USIM-2 as fake UE and blacklist USIM-1. In one example, the network sends error cause illegal UE or illegal ME to the UE. The UE on receiving this cause considers the registration procedure fails and does not initiate Registration procedure until the UE is power cycle or a new UICC is inserted in the ME.

In an embodiment, after registration and successful primary authentication, the serving network's AMF (200b) may receive the UE (100) s identification from the home network. The identification information received for authentication of multiple USIMs (150) may be used by the serving network's AMF (200b) to identify USIMs (150) belonging to the same UE (100) and use such information for multi-SIM optimizations. Additionally, the network (200) may consider multi USIM (150) optimizations based on an intent indication from the UE (100). Further, the network entity (200) itself figure out that both the USIM's (150aand150b) belong to the same UE (100) without any information indicating by the UE (100) and provide an indication to the UE (100). Further, the AMF (200b) obtains IMEIs/PEIs belonging to the same UE (100) and maps the SUPIs associated with the IMEIs of the UE (100) for multi-SIM optimizations.

In an embodiment, the UE (100) selects the primary SIM (i.e. first SIM (150a)) selected PLMN for the secondary SIM (i.e. second SIM (150b)), if the primary SIM (150a) selected PLMN is listed in the preferred PLMN list of secondary PLMN. Further, the UE (100) selects the PLMN if the PLMN is listed in the preferred PLMN list of both USIMs (150aand150b). Further, the UE (100) selects the PLMN, if it is HPLMN of any one of the USIMs and it selects the same PLMN for other USIMs also if HPLMN of other USIMs are not available.

The embodiments disclosed herein can be implemented using at least one software program running on at least one hardware device and performing network management functions to control the elements.

The foregoing description of the specific embodiments will so fully reveal the general nature of the embodiments herein that others can, by applying current knowledge, readily modify and/or adapt for various applications such specific embodiments without departing from the generic concept, and, therefore, such adaptations and modifications should and are intended to be comprehended within the meaning and range of equivalents of the disclosed embodiments. It is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation. Therefore, while the embodiments herein have been described in terms of preferred embodiments, those skilled in the art will recognize that the embodiments herein can be practiced with modification within the spirit and scope of the embodiments as described herein.