Patent Description:
To meet the demand for wireless data traffic having increased since deployment of 4th generation (<NUM>) communication systems, efforts have been made to develop an improved 5th generation (<NUM>) or pre-<NUM> communication system. In the <NUM> system, Hybrid FSK and QAM Modulation (FQAM) and sliding window superposition coding (SWSC) as an advanced coding modulation (ACM), and filter bank multi carrier (FBMC), non-orthogonal multiple access (NOMA), and sparse code multiple access (SCMA) as an advanced access technology have been developed.

In general, 3rd generation partnership project (3GPP) defines single registration mode and dual registration mode of operation for user equipments (UEs) supporting both S1 and N1 modes, in order to interwork with evolved UMTS terrestrial radio access network (E-UTRAN) connected to evolved packet core (EPC). In the dual registration mode, in case a UE is registered in the N1 mode and needs to get registered on the S1 mode, the UE has to use a public land mobile network (PLMN) to which the UE is registered in the N1 mode (i.e., a registered PLMN (RPLMN)) or an equivalent PLMN. Similarly, in case the UE is registered in the S1 mode and needs to get registered on the N1 mode, then the UE has to use the PLMN to which the UE is registered in the S1 mode (i.e., RPLMN) or the equivalent PLMN (EPLMN/EqPLMN).

However, there can be a scenario in which the UE registered on the N1 mode may not be able to receive service on the RPLMN/EPLMN on the S1 mode and vice versa and hence the UE is forced to maintain a single registration context, though it's capable of dual registration.

Also, in the methods and systems, there exists no mechanism for the UE to enter back into the dual-registration mode. Further, there are scenarios when a preferred mode of operation of the UE is the dual-registration mode and the UE wants to get back into the dual-registration mode at the earliest, which is not addressed by the methods and systems. In another scenario, there is no procedure defined for handling an expiry of a higher priority PLMN timer when the UE is in the dual-registration-mode. Further, the methods and systems do not define any procedure for handling manual selection of the PLMN by a user when the UE is in the dual- reg-istration-mode.

"<NPL>et al discloses that UEs operating in dual registration mode can choose PLMNs for registration which is RPLMN or EPLMN of N1 when a reject clause is received. <CIT> discloses a PLMN selection method wherein the UE scans the PLMNs until it finds a cell offering a selected pair RAT/ frequency. If not found, the UE may wait until a timer expires before scanning again for the same pair.

<FIG> illustrates an architecture for fourth generation (<NUM>) - fifth generation (<NUM>) core network (CN) level interworking with single registration mode and double registration mode according to the related art.

There can be a scenario in which the UE registered on the N1 mode may not be able to receive service on the RPLMN/EPLMN on the S1 mode and vice versa and hence the UE is forced to maintain a single registration context, though it's capable of dual registration.

Also, in the methods and systems, there exists no mechanism for the UE to enter back into the dual-registration mode. Further, there are scenarios when a preferred mode of operation of the UE is the dual-registration mode and the UE wants to get back into the dual-registration mode at the earliest, which is not addressed by the methods and systems. In another scenario, there is no procedure defined for handling an expiry of a higher priority PLMN timer when the UE is in the dual-registration-mode. Further, the methods and systems do not define any procedure for handling manual selection of the PLMN by a user when the UE is in the dual- registration mode.

The invention is set forth by the method of claim <NUM> and the user equipment of claim <NUM>. Aspects not covered by the scope of the claims are provided for illustration purpose only.

In accordance with an aspect of the disclosure, a method for performing PLMN selection by user equipment (UE) in dual registration mode is provided. The method includes registering, by the UE, on a registered PLMN (RPLMN) for receiving first wireless technology services and detecting, by the UE, unavailability of second wireless technology services in at least one of the RPLMN and an equivalent PLMN (EqPLMN), starting, by the UE, a periodic timer in response to detecting the unavailability of the second wireless technology services in at least one of the RPLMN and the EqPLMN, and performing, by the UE (<NUM>), the PLMN selection based on a PLMN scan after an expiry of the periodic timer. The UE is dual registration capable.

A method for performing by the UE, the PLMN selection based on the PLMN scan after the expiry of the periodic timer is provided. The method includes performing, by the UE, the PLMN scan on each expiry of the periodic timer to determine availability of the second wireless technology services on at on at least one of the RPLMN and the EqPLMN PLMN. Further, the method includes performing, by the UE, one of registering to one of the RPLMN and the EqPLMN in the dual registration mode to receive the second wireless technology services, if the second wireless technology services is available in at least one of the RPLMN and the EqPLMN, and performing another PLMN scan to determine whether a lower priority PLMN provides the first wireless technology services and the second wireless technology services, if the second wireless technology services is unavailable in at least one of the RPLMN and the EqPLMN.

In accordance with another aspect of the disclosure, user equipment (UE) for performing PLMN selection in dual registration mode is provided. The UE includes a memory and a processor coupled to the memory. The processor is configured to register on a registered PLMN (RPLMN) for connecting with first wireless technology services, detect unavailability of second wireless technology services in at least one of the RPLMN and an equivalent PLMN (EqPLMN). The UE (<NUM>) is dual registration capable, start a periodic timer in response to detecting the unavailability of the second wireless technology services, and perform the PLMN selection based on a PLMN scan after the expiry of the periodic timer.

A user equipment (UE) for performing PLMN selection in dual registration mode is provided. The UE includes a memory and a processor coupled to the memory. The processor is configured to determine that an active application in the UE requires only first wireless technology services, wherein the UE is dual registration capable and wherein the UE (<NUM>) is camped with a second wireless technology services RAT of a registered public land mobile network (RPLMN), determine that the RPLMN does not provide a first wireless technology services RAT and determine a user preference of the first wireless technology services RAT based on the active application, determine the PLMN which provides the first wireless technology services RAT in a single registration mode based on a PLMN scan, and manage the PLMN selection by registering with the PLMN which provides the first wireless technology services RAT in the single registration mode based on the PLMN scan.

The embodiments of the disclosure herein will be better appreciated and understood when considered in conjunction with the following description and the accompanying drawings.

Accordingly, an aspect of the disclosure is to provide a method and system for performing PLMN selection in dual registration mode.

Another aspect of the disclosure is to determine a PLMN scan to determine one of a registered public land mobile network (RPLMN) and an equivalent PLMN of the RPLMN for providing a second wireless technology services failed.

Another aspect of the disclosure is to activate a periodic timer in response to determining that the PLMN scan is failed and waiting for the periodic timer to expire.

Another aspect of the disclosure is to perform the PLMN selection based on a next PLMN scan performed after expiry of the periodic timer.

Another aspect of the disclosure is to display a list of PLMNs based on the PLMN scan along with an indication of availability of the dual-registration mode for each of the PLMN in a list of PLMNs.

Another aspect of the disclosure is to manage the PLMN selection for a preferred mode of registration based on a PLMN scan when a higher priority PLMN timer associated with a home public land mobile network (HPLMN) of the UE (<NUM>) is expires.

In accordance with another aspect of the disclosure, a method for performing by the UE, the PLMN selection based on the PLMN scan after the expiry of the periodic timer is provided. The method includes performing, by the UE, the PLMN scan on each expiry of the periodic timer to determine availability of the second wireless technology services on at on at least one of the RPLMN and the EqPLMN PLMN. Further, the method includes performing, by the UE, one of registering to one of the RPLMN and the EqPLMN in the dual registration mode to receive the second wireless technology services, if the second wireless technology services is available in at least one of the RPLMN and the EqPLMN, and performing another PLMN scan to determine whether a lower priority PLMN provides the first wireless technology services and the second wireless technology services, if the second wireless technology services is unavailable in at least one of the RPLMN and the EqPLMN.

In an embodiment of the disclosure, performing the other PLMN scan to determine whether the lower priority PLMN which provides both the first wireless technology services and the second wireless technology services is available includes checking, by the UE (<NUM>), availability of the first wireless technology services and the second wireless technology services on the lower priority PLMN. Further, the method includes performing, by the UE (<NUM>), one of registering to the lower priority PLMN if the lower priority PLMN provides the first wireless technology services and the second wireless technology services in the dual registration mode, and continuing to receive only the first wireless technology services over the RPLMN in a single registration mode, if the lower priority PLMN does not provide the first wireless technology services and the second wireless technology services.

In an embodiment of the disclosure, the method further includes determining, by the UE (<NUM>), a number of PLMN scans performed is greater than a PLMN scan threshold and activating, by the UE (<NUM>), a long timer, wherein duration of the long timer is greater than duration of the periodic timer. Further, the method also includes suspending, by the UE (<NUM>), the PLMN scan when the long timer is active.

In an embodiment of the disclosure, the first wireless technology services is <NUM> services and the second wireless technology services is fifth generation (<NUM>) services.

In an embodiment of the disclosure, the first wireless technology services is <NUM> services and the second wireless technology services is fourth generation (<NUM>) services.

In an embodiment of the disclosure, the periodic timer is one of an incremental timer and a higher priority PLMN timer.

In accordance with another aspect of the disclosure, a method for managing PLMN selection by user equipment (UE) in dual registration mode is provided. The method includes determining, by the UE, that an active application in the UE requires only a first wireless technology service, where the UE is dual registration capable, wherein the UE is camped with a second wireless technology services radio access technology (RAT) of a registered public land mobile network (RPLMN), determining, by the UE, that the RPLMN does not provide a first wireless technology services RAT and determining, by the UE, a user preference of the first wireless technology services RAT based on the active application, determining, by the UE, the PLMN which provides the first wireless technology services RAT in a single registration mode based on a PLMN scan, and managing, by the UE), the PLMN selection by registering with the PLMN which provides the first wireless technology services RAT in the single registration mode based on the PLMN scan.

In accordance with another aspect of the disclosure, a method for managing PLMN selection by user equipment (UE) in dual registration mode is provided. The method includes registering, by the UE, to a RPLMN for receiving <NUM> services and <NUM> services in the dual-registration mode and determining, by the UE, a higher priority PLMN timer associated with a HPLMN of the UE (<NUM>) has expired, determining, by the UE, that a preferred registration mode is one of the dual registration mode and a single registration mode based on a set of parameters, and managing, by the UE, the PLMN selection for the preferred mode of registration based on a PLMN scan.

In accordance with another aspect of the disclosure, a method for managing PLMN selection by user equipment (UE) in dual registration mode is provided. The method includes receiving, by the UE, a manual PLMN scan request, wherein the UE is registered to a RPLMN for receiving <NUM> services and <NUM> services in the dual-registration mode, performing, by the UE, a PLMN scan in response to the manual PLMN scan request received by the UE displaying, by the UE, a list of PLMNs based on the PLMN scan along with an indication of availability of the dual-registration mode for each of the PLMN in the list of PLMNs, receiving, by the UE, an input indicating a selection of a PLMN from the list of PLMNs displayed, and managing, by the UE, the PLMN selection by registering to the PLMN selected based on the input.

In accordance with another aspect of the disclosure, user equipment (UE) for performing PLMN selection in dual registration mode is provided. The UE includes a memory and a processor coupled to the memory. The processor is configured to determine that an active application in the UE requires only first wireless technology services, wherein the UE is dual registration capable and wherein the UE (<NUM>) is camped with a second wireless technology services RAT of a registered public land mobile network (RPLMN), determine that the RPLMN does not provide a first wireless technology services RAT and determine a user preference of the first wireless technology services RAT based on the active application, determine the PLMN which provides the first wireless technology services RAT in a single registration mode based on a PLMN scan, and manage the PLMN selection by registering with the PLMN which provides the first wireless technology services RAT in the single registration mode based on the PLMN scan.

In accordance with another aspect of the disclosure, user equipment (UE) for performing PLMN selection in dual registration mode is provided. The UE includes a memory and a processor coupled to the memory. The processor is configured to register to a RPLMN for receiving <NUM> services and <NUM> services in the dual-registration mode, determine that a higher priority PLMN timer associated with a HPLMN of the UE has expired, determine that a preferred registration mode is one of the dual registration mode and a single registration mode based on a set of parameters, and manage the PLMN selection for the preferred mode of registration based on a PLMN scan.

In accordance with another aspect of the disclosure, user equipment (UE) for performing PLMN selection in dual registration mode is provided. The UE includes a memory and a processor coupled to the memory. The processor is configured to receive a manual PLMN scan request, wherein the UE is registered to a RPLMN for receiving <NUM> services and <NUM> services in the dual-registration mode, perform a PLMN scan in response to the manual PLMN scan request received by the UE, display a list of PLMNs based on the PLMN scan along with an indication of availability of the dual-registration mode for each of the PLMN in the list of PLMNs, receive an input indicating a selection of a PLMN from the list of PLMNs displayed, and manage the PLMN selection by registering to the PLMN selected based on the input.

The embodiments of the disclosure herein will be better appreciated and understood when considered in conjunction with the following description and the accompanying drawings. Many changes and modifications may be made within the scope of the embodiments herein without departing from the spirit thereof, and the embodiments herein include all such modifications.

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 and 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 disclosure. Likewise, the blocks of the embodiments may be physically combined into more complex blocks without departing from the scope of the disclosure.

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 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.

Accordingly the embodiments herein disclose a method for performing public land mobile network (PLMN) selection by user equipment (UE) (<NUM>) in dual registration mode. The method includes determining, by the UE (<NUM>), a PLMN scan to determine one of: a registered public land mobile network (RPLMN) and an equivalent PLMN of the RPLMN for providing a second wireless technology services failed, where the UE (<NUM>) is dual registration capable and where the UE (<NUM>) is registered for a first wireless technology services on the RPLMN. The method also includes activating, by the UE (<NUM>), a periodic timer in response to determining that the PLMN scan is failed and determining, by the UE (<NUM>), an expiry of the activated periodic timer periodically. Further, the method includes performing, by the UE (<NUM>), the PLMN selection based on a next PLMN scan.

Referring now to the drawings and more particularly to <FIG>, where similar reference characters denote corresponding features consistently throughout the figure, these are shown preferred embodiments.

<FIG> is a block diagram illustrating user equipment (UE) (<NUM>) for performing PLMN selection in dual registration mode, according to an embodiment of the disclosure.

Referring to <FIG>, the UE (<NUM>) can be but not limited to, for example, a mobile electronic device, a smart electronic device, personal digital assistant (PDA), a tablet or the like. The UE (<NUM>) includes a memory (<NUM>), a display (<NUM>) and a processor (<NUM>).

In an embodiment, the memory (<NUM>) can 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 (<NUM>) 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 (<NUM>) is non-movable. In some examples, the memory (<NUM>) is 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 display (<NUM>) is configured to display a list of PLMNs based on the PLMN scan along with an indication of availability of the dual-registration mode for each of the PLMN in the list of PLMNs and receive an input indicating a selection of a PLMN from the list of PLMNs displayed. Further, the display (<NUM>) is configured to display a warning message indicating that the dual registration provided by the registered PLMN (RPLMN) is not available in the PLMN selected by the user based on the input received from the user on the display (<NUM>) of the UE (<NUM>) and suggest at least one PLMN which supports the dual registration mode from the list of PLMNs.

The processor (<NUM>) includes a timer management engine (<NUM>), a priority management engine (<NUM>), PLMN selection engine (<NUM>), a registration management engine (<NUM>) and a learning engine (<NUM>).

In an embodiment, the timer management engine (<NUM>) is configured to determine a higher priority PLMN timer associated with a home public land mobile network (HPLMN) of the UE (<NUM>) is expired.

In an embodiment, the timer management engine (<NUM>) is configured to activate the timer on determining the at least one higher priority PLMN which provides one of the <NUM> services and the <NUM> services and wait for the activated timer to expire to determine when to switch to the dual registration mode from the single registration mode based on the PLMN scan.

In an embodiment, the timer management engine (<NUM>) is configured to activate a periodic timer in response to determining that the PLMN scan is failed and wait for an expiry of the activated periodic timer periodically after which the PLMN scan is performed. Further, before activating the periodic timer again after expiry, the periodic timer is incremented for example in time intervals of <NUM>,<NUM>,<NUM>,<NUM>. Further, the timer management engine (<NUM>) is configured to activate a long timer based on an indication from the PLMN selection engine (<NUM>) when a number of PLMN scans performed is greater than a PLMN scan threshold. A duration of the long timer is greater than a duration of the periodic timer, for example 6hrs-24hrs as compared to the <NUM>,<NUM>,<NUM>,<NUM>. seconds of the periodic timer.

In an embodiment, the priority management engine (<NUM>) is configured to determine a priority associated with any PLMN which is identified based on the PLMN scan performed by the PLMN selection engine (<NUM>).

In an embodiment, the PLMN selection engine (<NUM>) is configured to perform the next PLMN scan on each expiry of the periodic timer to determine one of the RPLMN and the equivalent PLMN of the RPLMN for providing the second wireless technology services. Further, the PLMN selection engine (<NUM>) is configured to perform another PLMN scan to determine whether a lower priority PLMN which provides both the first wireless technology services and the second wireless technology services is available, in response to determining that the next PLMN scan to determine one of the RPLMN and the equivalent PLMN of the RPLMN for providing the second wireless technology services is not successful. Furthermore, the PLMN selection engine (<NUM>) is configured to determine a number of PLMN scans performed are greater than a PLMN scan threshold and indicate the timer management engine (<NUM>) to activate a long timer and suspend the PLMN scan when the long timer is active. The first wireless technology services is <NUM> services and the second wireless technology services is <NUM> services. The first wireless technology services is <NUM> services and the second wireless technology services is <NUM> services. The periodic timer is one of an incremental timer and a higher priority PLMN timer.

In another embodiment, the PLMN selection engine (<NUM>) is configured to determine whether at least one higher priority PLMN is available which provides the <NUM> services and the <NUM> services in the dual registration mode based on the PLMN scan when the preferred registration mode is the dual registration mode and manage the PLMN selection for the dual registration mode based on the PLMN scan. Further, the PLMN selection engine (<NUM>) is also configured to determine at least one higher priority PLMN which provides one of <NUM> services and <NUM> services based on the PLMN scan when the preferred registration mode is the single registration mode and manage the PLMN selection in the single registration mode by registering to the at least one higher priority PLMN which provides one of the <NUM> services and the <NUM> services.

In another embodiment, the PLMN selection engine (<NUM>) is configured to receive a manual PLMN scan request and perform the PLMN scan in response to the manual PLMN scan request received by the UE (<NUM>). Further, the PLMN selection engine (<NUM>) is configured to identify the list of PLMNs based on the PLMN scan and display the same on the display (<NUM>) along with the indication of availability of the dual-registration mode for each of the PLMN in the list of PLMNs and identify the PLMN selected by the user based on the input received on the display (<NUM>) selecting the PLMN from the list of PLMNs displayed. Further, the PLMN selection engine (<NUM>) is also configured to determine whether the PLMN selected from the list of PLMNs manually by the user supports the dual registration mode. Further, in response to determining that the PLMN selected from the list of PLMNs does not support the dual registration mode, the PLMN selection engine (<NUM>) is also configured to provide the warning message on the display (<NUM>) indicating that the dual registration provided by the RPLMN is not available in the selected PLMN and also suggest at least one PLMN which supports the dual registration mode from the list of PLMNs.

In another embodiment, the PLMN selection engine (<NUM>) is configured to determine an active application in the UE (<NUM>) requires only a first wireless technology services and determine that the RPLMN does not provide a first wireless technology services RAT. Further, the PLMN selection engine (<NUM>) is configured to determine a user preference of the first wireless technology services RAT based on the active application and determine the PLMN which provides the first wireless technology services RAT in the single registration mode based on the PLMN scan.

In an embodiment, the registration management engine (<NUM>) is configured to register to one of: the RPLMN and the equivalent PLMN of the RPLMN in the dual registration mode to receive the second wireless technology services, in response to determining that the next PLMN scan to determine one of: the RPLMN and the equivalent PLMN of the RPLMN for providing the second wireless technology services is successful. In another embodiment, the registration management engine (<NUM>) is configured to register to the lower priority PLMN which provides both the first wireless technology services and the second wireless technology services in the dual registration mode, in response to determining the other PLMN scan to determine the lower priority PLMN which provides both the first wireless technology services and the second wireless technology services is successful and continue to be registered to the RPLMN to receive only the first wireless technology services in a single registration mode, in response to determining the other PLMN scan to determine the lower priority PLMN which provides both the first wireless technology services and the second wireless technology services is not successful.

In another embodiment, the registration management engine (<NUM>) is configured to determine a preferred registration mode is one of the dual registration mode and a single registration mode based on a set of parameters. The set of parameters includes inputs received from the learning engine (<NUM>), user preference, a usage pattern of a user, a quality of service on the PLMN at a particular area, applications in the UE (<NUM>), data stall, Radio layer failure (low RSRP, error rate), Temperature, Battery level, NITZ time, GPS location, artificial intelligence, Cell ID, PLMN, TAI etc. The set of parameters are also used to provide the preferred RAT list (in the priority order) and the preferred PLMN list (in the priority order).

Further, the registration management engine (<NUM>) is configured to register to a higher priority PLMN of the at least one higher priority PLMN which provides the <NUM> services and the <NUM> services in the dual-registration mode, in response to determining that the at least one higher priority PLMN which provides the <NUM> services and the <NUM> services in the dual registration mode based on the PLMN scan is available, and continue to operate with the RPLMN which provides the <NUM> services and the <NUM> services in the dual-registration mode, in response to determining that the at least one higher priority PLMN which provides the <NUM> services and the <NUM> services in the dual registration mode based on the PLMN scan is not available. Further, the registration management engine (<NUM>) is configured to register to the at least one higher priority PLMN which provides one of the <NUM> services and the <NUM> services, when the preferred registration mode is the single registration mode.

In another embodiment, the registration management engine (<NUM>) is configured to register to the PLMN manually selected by the user from the list of PLMNs provided by the PLMN selection engine (<NUM>).

In an embodiment, the learning engine (<NUM>) is configured to provide an indication to the PLMN selection engine (<NUM>) to perform the PLMN scan after a long time break when the number of PLMN scans performed is greater than the PLMN scan threshold. In another embodiment, the learning engine (<NUM>) is configured to provide inputs to the registration management engine (<NUM>) to determine the preferred registration mode. The learning could include but not limited to, quality of service on a certain PLMN at a particular area, user's usage pattern (if user wants ultra reliable low latency communication (URLLC) kind of service or delay tolerant service at a particular time etc..

Although the <FIG> shows the hardware elements of the UE (<NUM>) but it is to be understood that other embodiments are not limited thereon. In other embodiments, the UE (<NUM>) may include less or more number of elements. Further, the labels or names of the elements are used only for illustrative purpose and does not limit the scope. One or more components can be combined together to perform same or substantially similar function.

<FIG> is a signal diagram illustrating example scenario where a time period for returning to the dual registration mode by the UE (<NUM>) is not defined in 3GPP during the PLMN selection, according to an embodiment of the disclosure.

Referring to <FIG>, at operation <NUM>, consider a scenario when the dual registration capable UE (<NUM>) is powered ON and the UE (<NUM>) is registered to the fifth generation radio access technology (<NUM> RAT) (N1 mode) on the RPLMN to receive the <NUM> services (as shown in operation <NUM>). Generally, according to standard specifications, the UE (<NUM>) first performs the PLMN scan for the fourth generation radio access technology (<NUM> RAT) (S1 mode) on the RPLMN. Further, the UE (<NUM>) performs the PLMN scan to determine the availability of the <NUM> RAT on the equivalent PLMN of the RPLMN to receive the <NUM> services. However, at operation <NUM>, the PLMN scan to determine the <NUM> RAT on the RPLMN and the equivalent PLMN both fails and the UE (<NUM>) is forced to maintain a single registration context (only in the access and mobility management function (AMF)), though the UE (<NUM>) is capable of dual registration.

Referring to <FIG>, in conjunction with the <FIG>, the UE (<NUM>) which is dual registration capable in another scenario may be registered to the <NUM> RAT (S1 mode) successfully on the RPLMN (as shown in operation <NUM>). Further, at operation <NUM>, the PLMN scan for the <NUM> RAT (N1 mode) registration on one of the RPLMN and the EqPLMN of the <NUM> RAT fails and hence forcing the UE (<NUM>) to maintain a single registration context (only in the mobility management entity (MME)), though the UE (<NUM>) is capable of operating in the dual registration.

In the methods and systems; and in the 3GPP standard specifications, the procedure for the UE (<NUM>) to return to the dual registered mode is not defined. Therefore, due to the lack of procedure, the UE (<NUM>) may be forced to continue operating in the single registration mode even though the UE (<NUM>) is dual registration capable rendering the capability of the UE (<NUM>) in vain and under-utilized.

<FIG> is a signal diagram illustrating the example scenario where the periodic timer is activated by the UE (<NUM>) when the PLMN scan fails to return to the dual registration mode, according to an embodiment of the disclosure.

Referring to <FIG>, in conjunction with the <FIG>, the operations <NUM> and 2a in the <FIG> may be substantially the same as operations <NUM> and <NUM> described in the <FIG>, and thus repeated description is omitted.

At operation 2b, the UE (<NUM>) activates the periodic timer in response to determining that the PLMN scan is failed for the <NUM> services. The periodic timer is activated for a period of 'X' seconds. The periodic timer is implementation specific and can be one of: dual reg try back timer or higher priority PLMN timer.

At operation <NUM>, the UE (<NUM>) determines the expiry of the activated periodic timer and performs the next PLMN scan to determine one of the RPLMN and the equivalent PLMN of the RPLMN for providing the <NUM> services. In the operation <NUM>, in case the next PLMN scan is successful, then the UE (<NUM>) will latch to the one of the RPLMN and the equivalent PLMN of the RPLMN which is determined based on the next PLMN scan for the <NUM> services.

In the operation <NUM>, in case the next PLMN scan is unsuccessful, then at operation <NUM> the UE (<NUM>) performs another PLMN scan to determine the availability of the lesser priority PLMN which provides both the <NUM> and the <NUM> services. The UE (<NUM>) if the same PLMN can be found on both the RATs. In case the operation <NUM> is successful then the UE (<NUM>) is dual registered with the lesser priority PLMN for both the <NUM> and the <NUM> services. Further, if the operation <NUM> fails, then the UE (<NUM>) remains in the operation <NUM> and the periodic timer is activated again after being incremented for a period of '2X' seconds. Further, the operations <NUM>-<NUM> are repeated until a PLMN which provides both the <NUM> services and the <NUM> services is found.

Furthermore, the UE (<NUM>) determines that the number of PLMN scans performed is greater than the PLMN scan threshold. In response to determining that the number of PLMN scans performed is greater than the PLMN scan threshold the UE (<NUM>) activates the long timer (6hrs-24hrs) which has the duration greater than the duration of the periodic timer and suspends the PLMN scan when the long timer is active. Therefore, the UE (<NUM>) will not scan until the UE (<NUM>) receives the indication from the learning engine (<NUM>) and/or motion/grip sensor(s) and/or user interface or long-timer-expiry.

Furthermore, the UE (<NUM>) can decide the priority RAT and register on the priority RAT with the RPLMN (say <NUM>, N1 mode). The UE (<NUM>) may decide on the priority RAT based on the inputs received from the learning engine (<NUM>). The inputs will be regarding which RAT provides better service in a particular area etc..

<FIG> is another signal diagram illustrating the example scenario where the periodic timer is activated by the UE (<NUM>) when the PLMN scan fails to return to the dual registration mode, according to an embodiment of the disclosure.

In the operation <NUM>, in case the next PLMN scan is unsuccessful, then at operation <NUM> the UE (<NUM>) performs another PLMN scan to determine the availability of the lesser priority PLMN which provides both the <NUM> and the <NUM> services. The UE (<NUM>) determines if the same PLMN can be found on both the RATs. In case the operation <NUM> is successful then the UE (<NUM>) is dual registered with the lesser priority PLMN for both the <NUM> and the <NUM> services. Further, if the operation <NUM> fails, then the UE (<NUM>) remains in the operation <NUM> and the periodic timer is activated again after being incremented for a period of '2X' seconds. Further, the operations <NUM>-<NUM> are repeated until the PLMN which provides both the <NUM> services and the <NUM> services is found.

<FIG> is a flow chart illustrating the method for performing PLMN selection by the UE (<NUM>) in the dual registration mode when the UE (<NUM>) is registered to a <NUM> RAT, according to an embodiment of the disclosure.

Referring to <FIG>, at operation 302a, the dual registration capable UE (<NUM>) is registered to the <NUM> RAT successfully on the RPLMN.

At operation 304a, the UE (<NUM>) performs the PLMN scan for the <NUM> RAT on the RPLMN and determines whether the PLMN scan is successful. At operation 306a, in response to determining that the PLMN scan for the <NUM> RAT on the RPLMN is successful, the UE (<NUM>) initiates a state A.

Further, at operation 308a, in response to determining that the PLMN scan for the <NUM> RAT on the RPLMN is not successful, the UE (<NUM>) performs the PLMN scan to determine the availability of the <NUM> RAT on the Equivalent PLMN of the RPLMN and determines whether the PLMN scan is successful.

At operation 308a, in response to determining that the PLMN scan for the <NUM> RAT on the Equivalent PLMN of the RPLMN is successful, the UE (<NUM>) loops to operation 306a and initiates the state A.

At operation 310a, in response to determining that the PLMN scan for the <NUM> RAT on the equivalent PLMN of the RPLMN is unsuccessful, the UE (<NUM>) determines whether Nscanfailure which is the number of PLMN scans is less than or equal to <NUM>. At operation 312a, the UE (<NUM>) starts the DualRegTryBackTimer or the HigherPriorityPLMNTimer with duration TDualRegTryBackTimer = X sec and waits till at operation 314a, the expiry of the DualRegTryBackTimer or HigherPriorityPLMNTimer. Further, in response to determining that the DualRegTryBackTimer or HigherPriorityPLMNTimer is expired, the UE (<NUM>) loops to the operation 304a and performs the PLMN scan for the <NUM> RAT on the RPLMN.

At operation 310a, in response to determining that the Nscanfailure is not less than or equal to <NUM>, the UE (<NUM>) increments the DualRegTryBackTimer or HigherPriorityPLMNTimer by incrementing the duration as T DualRegTryBackTimer = <NUM> * T DualRegTryBackTimer sec and at operation 316a, the UE (<NUM>) determines whether NscanFailure is greater than a MAXscanFailure threshold.

At operation 316a, in response to determining that the NscanFailure is greater than a MAXscanFailure threshold, the UE (<NUM>) at operation 318a initiates a state B. At operation 316a, in response to determining that the NscanFailure is not greater than a MAXscanFailure threshold, the UE (<NUM>) at operation 320a initiates the PLMN scan to determine the <NUM> RAT and the <NUM> RAT registration on the lesser priority PLMN.

At operation 322a, the UE (<NUM>) determines whether the PLMN scan to determine the <NUM> RAT and the <NUM> RAT registration on the lesser priority PLMN is successful. Further, at operation 322a, in response to determining that the PLMN scan to determine the <NUM> RAT and the <NUM> RAT registration on the lesser priority PLMN is successful, the UE (<NUM>) initiates the state A (at operation 306a). At operation 322a, in response to determining that the PLMN scan to determine the <NUM> RAT and the <NUM> RAT registration on the lesser priority PLMN is not successful, the UE (<NUM>) loops to operation 310a.

The various actions, acts, blocks, operations, or the like in the method may be performed in the order presented, in a different order or simultaneously. Further, in some embodiments, some of the actions, acts, blocks, operations, or the like may be omitted, added, modified, skipped, or the like without departing from the scope.

Referring to <FIG>, at operation 302b, the dual registration capable UE (<NUM>) is registered to the <NUM> RAT successfully on the RPLMN.

At operation 304b, the UE (<NUM>) performs the PLMN scan for the <NUM> RAT on the RPLMN and determines whether the PLMN scan is successful. At operation 306b, in response to determining that the PLMN scan for the <NUM> RAT on the RPLMN is successful, the UE (<NUM>) initiates a state A.

Further, at operation 308b, in response to determining that the PLMN scan for the <NUM> RAT on the RPLMN is not successful, the UE (<NUM>) performs the PLMN scan to determine the availability of the <NUM> RAT on the equivalent PLMN of the RPLMN and determines whether the PLMN scan is successful.

At operation 308b, in response to determining that the PLMN scan for the <NUM> RAT on the Equivalent PLMN of the RPLMN is successful, the UE (<NUM>) loops to operation 306b and initiates the state A.

At operation 310b, in response to determining that the PLMN scan for the <NUM> RAT on the Equivalent PLMN of the RPLMN is unsuccessful, the UE (<NUM>) determines whether Nscanfailure which is the number of PLMN scans is less than or equal to <NUM>. At operation 312b, the UE (<NUM>) starts the DualRegTryBackTimer or the HigherPriorityPLMNTimer with duration TDualRegTryBackTimer = X sec and waits till at operation 314b, the expiry of the DualRegTryBackTimer or HigherPriorityPLMNTimer. Further, in response to determining that the DualRegTryBackTimer or HigherPriorityPLMNTimer is expired, the UE (<NUM>) loops to the operation 304b and performs the PLMN scan for the <NUM> RAT on the RPLMN.

At operation 310b, in response to determining that the Nscanfailure is not less than or equal to <NUM>, the UE (<NUM>) increments the DualRegTryBackTimer or HigherPriorityPLMNTimer by incrementing the duration as T DualRegTryBackTimer = <NUM> * T DualRegTryBackTimer sec and at operation 316b, the UE (<NUM>) determines whether NscanFailure is greater than a MAXscanFailure threshold.

At operation 316b, in response to determining that the NscanFailure is greater than a MAXscanFailure threshold, the UE (<NUM>) at operation 318b initiates a state C. At operation 316b, in response to determining that the NscanFailure is not greater than a MAXscanFailure threshold, the UE (<NUM>) at operation 320b initiates the PLMN scan to determine the <NUM> RAT and the <NUM> RAT registration on the lesser priority PLMN.

At operation 322b, the UE (<NUM>) determines whether the PLMN scan to determine the <NUM> RAT and the <NUM> RAT registration on the lesser priority PLMN is successful. Further, at operation 322b, in response to determining that the PLMN scan to determine the <NUM> RAT and the <NUM> RAT registration on the lesser priority PLMN is successful, the UE (<NUM>) initiates the state A (at operation 306b). At operation 322b, in response to determining that the PLMN scan to determine the <NUM> RAT and the <NUM> RAT registration on the lesser priority PLMN is not successful, the UE (<NUM>) loops to operation 310b.

<FIG> illustrates various states of the dual registration capable UE (<NUM>), according to an embodiment of the disclosure.

Referring to <FIG>, state A includes the UE (<NUM>) in dual registration mode where the UE (<NUM>) is registered for both the <NUM> service and the <NUM> service with the same PLMN. The PLMN may be one of: the RPLMN, equivalent PLMN of the RPLMN, lesser priority PLMN and any PLMN which provides both the <NUM> service and the <NUM> service.

State B includes the dual registration capable UE (<NUM>) which is registered only for the <NUM> service with the PLMN.

State C includes the dual registration capable UE (<NUM>) which is registered only for the <NUM> service with the PLMN.

<FIG> is a signal diagram illustrating a scenario of the expiry of a higher priority PLMN timer when the UE (<NUM>) is dual registered, according to an embodiment of the disclosure.

Referring to <FIG>, consider that the dual registration capable UE (<NUM>) is registered to both the <NUM> RAT and the <NUM> RAT successfully on the RPLMN (operation <NUM>). At operation <NUM>, the UE (<NUM>) determines that the higher priority PLMN timer associated with the HPLMN of the UE (<NUM>) is expired. Further, at operation <NUM>, in response to determining that the higher priority PLMN timer associated with the HPLMN of the UE (<NUM>) is expired, the UE (<NUM>) performs the PLMN scan to determine the availability of the higher priority PLMN for both the <NUM> service and the <NUM> service. At operation <NUM>, the UE (<NUM>) determines that the PLMN scan to determine the higher priority PLMN is successful only for the <NUM> RAT and fails for the <NUM> RAT (context in access and mobility management function (AMF) only).

Similarly referring to the <FIG>, operation <NUM> and operation <NUM> of the <FIG> may be substantially the same as the operation <NUM> and operation <NUM> of the <FIG>, and, thus repeated description is omitted. Further, at operation <NUM>, in response to determining that the higher priority PLMN timer associated with the HPLMN of the UE (<NUM>) is expired, the UE (<NUM>) performs the PLMN scan to determine the availability of the higher priority PLMN for both the <NUM> service and the <NUM> service. At operation <NUM>, the UE (<NUM>) determines that the PLMN scan to determine the higher priority PLMN is successful only for the <NUM> RAT and fails for the <NUM> RAT (context in mobility management entity (MME) only).

Therefore, in both the above mentioned scenarios the UE (<NUM>) is forced to maintain the single registration context (only in the AMF or MME), though the UE (<NUM>) is capable of the dual registration since there is no procedure defined in the 3GPP <NUM> for handling the higher priority PLMN timer expiry when the UE (<NUM>) is in the dual registration mode.

<FIG> is a signal diagram illustrating a scenario of the expiry of the higher priority PLMN timer when the preferred mode of operation is the dual registration mode, according to an embodiment of the disclosure.

Referring to <FIG> in conjunction with the <FIG>, the operations <NUM> and <NUM> in the <FIG> may be substantially the same as operations <NUM> and <NUM> described in the <FIG>, and thus repeated description is omitted.

At operation <NUM>, the registration management engine (<NUM>) of the UE (<NUM>) determines the preferred registration mode as the dual registration mode based on the inputs from the learning engine (<NUM>) and the user preference settings. Further, at operation <NUM>, the UE (<NUM>) performs the PLMN scan and determines that the PLMN scan for the higher priority PLMN is successful only for the <NUM> service and fails for the <NUM> service.

At operation <NUM>, in response to determining that the higher priority PLMN for providing both the <NUM> services and the <NUM> services in the dual registration mode is not available, the UE (<NUM>) continues to operate with the RPLMN which provides both the <NUM> services and the <NUM> services in the dual-registration mode.

At operation <NUM>, in response to determining that the at least one higher priority PLMN which provides the <NUM> services and the <NUM> services in the dual registration mode is available, the UE (<NUM>) registers to the higher priority PLMN which provides both the <NUM> services and the <NUM> services in the dual-registration mode.

Referring to <FIG> in conjunction with the <FIG>, the operations <NUM> to operation <NUM> in the <FIG> may be substantially the same as operations <NUM> to operation <NUM> described in the <FIG>, and thus repeated description is omitted. At operation <NUM>, the UE (<NUM>) performs the PLMN scan and determines that the PLMN scan for the higher priority PLMN is successful only for the <NUM> service and fails for the <NUM> service. At operation <NUM>, in response to determining that the higher priority PLMN for providing both the <NUM> services and the <NUM> services in the dual registration mode is not available, the UE (<NUM>) continues to operate with the RPLMN which provides both the <NUM> services and the <NUM> services in the dual-registration mode.

<FIG> is a flow chart illustrating the method for performing the PLMN selection by the UE (<NUM>) in the dual registration mode on expiry of the higher priority PLMN timer, according to an embodiment of the disclosure.

Referring to <FIG>, at operation 402a, the UE (<NUM>) registers to the RPLMN for receiving the <NUM> services and the <NUM> services in the dual-registration mode.

At operation 404a, the UE (<NUM>) determines that the higher priority PLMN timer associated with the HPLMN of the UE (<NUM>) is expired. Further, at operation 406a, the UE (<NUM>) determines whether the preferred registration mode is the dual registration mode based on the set of parameters received from the registration management engine (<NUM>).

At operation 408a, the UE (<NUM>), in response to determining that the preferred registration mode is not the dual registration mode, operates in the single registration mode. At operation 410a, in response to determining that the preferred registration mode is the dual registration mode, the UE (<NUM>) performs the PLMN scan for the <NUM> and the <NUM> registration on the higher priority PLMN.

At operation 412a, the UE (<NUM>) determines whether at least one higher priority PLMN is available which provides the <NUM> services and the <NUM> services in the dual registration mode based on the PLMN scan.

At operation 414a, in response to determining that the at least one higher priority PLMN is available which provides the <NUM> services and the <NUM> services in the dual registration mode based on the PLMN scan, the UE (<NUM>) registers to the higher priority PLMN (state A).

At operation 416a, in response to determining that the at least one higher priority PLMN is not available which provides the <NUM> services and the <NUM> services in the dual registration mode based on the PLMN scan, the UE (<NUM>) continues to operate with the RPLMN which provides the <NUM> services and the <NUM> services in the dual-registration mode.

<FIG> is a signal diagram illustrating a scenario of the expiry of the higher priority PLMN timer when the preferred mode of operation is a single registration mode, according to an embodiment of the disclosure.

At operation <NUM>, the registration management engine (<NUM>) of the UE (<NUM>) determines the preferred registration mode as the single registration mode based on the inputs from the learning engine (<NUM>) and the user preference settings. Further, at operation <NUM>, the UE (<NUM>) performs the PLMN scan and determines that the PLMN scan for the higher priority PLMN is successful only for the <NUM> service and fails for the <NUM> service.

At operation <NUM>, the UE (<NUM>) registers to the higher priority PLMN which provides only the <NUM> service in the single registration mode and simultaneously activates the timer (example, the DualRegTryBackTime). Further, the UE (<NUM>) waits for the activated timer to expire so that the UE (<NUM>) can perform the PLMN scan to switch to the dual registration mode from the single registration mode.

Referring to <FIG> in conjunction with the <FIG>, the operations <NUM> to operation <NUM> in the <FIG> may be substantially the same as operations <NUM> to operation <NUM> described in the <FIG>, and thus repeated description is omitted. At operation <NUM>, the UE (<NUM>) performs the PLMN scan and determines that the PLMN scan for the higher priority PLMN is successful only for the <NUM> service and fails for the <NUM> service.

At operation <NUM>, the UE (<NUM>) registers to the higher priority PLMN which provides only the <NUM> service in the single registration mode and simultaneously activates the timer (example, the DualRegTryBackTimer). Further, the UE (<NUM>) waits for the activated timer to expire so that the UE (<NUM>) can perform the PLMN scan to switch to the dual registration mode from the single registration mode. The UE (<NUM>) shall perform the higher priority PLMN SCAN when the UE (<NUM>) in both the RAT's <NUM> and <NUM> moves to IDLE mode.

<FIG> is a flow chart illustrating the method for performing the PLMN selection by the UE (<NUM>) in the single registration mode on the expiry of the higher priority PLMN timer, according to an embodiment of the disclosure.

Referring to the <FIG>, at operation 402b, the UE (<NUM>) registers to the RPLMN for receiving the <NUM> services and the <NUM> services in the dual-registration mode. At operation 404b, the UE (<NUM>) determines that the higher priority PLMN timer associated with the HPLMN of the UE (<NUM>) is expired. Further, at operation 406b, the UE (<NUM>) determines whether the preferred registration mode is the single registration mode based on the set of parameters received from the registration management engine (<NUM>).

At operation 408b, the UE (<NUM>), in response to determining that the preferred registration mode is not the single registration mode, operates in the dual registration mode (as described in <FIG>).

At operation 410b, in response to determining that the preferred registration mode is the single registration mode, the UE (<NUM>) performs the PLMN scan for the preferred RAT registration on the higher priority PLMN. At operation 412b, the UE (<NUM>) determines whether the PLMN scan for the preferred RAT registration on the higher priority PLMN is successful.

At operation 414b, in response to determining that the PLMN scan for the preferred RAT registration on the higher priority PLMN is successful, the UE (<NUM>) registers to the higher priority PLMN (state B). At operation 416b, in response to determining that PLMN scan for the preferred RAT registration on the higher priority PLMN is not successful, the UE (<NUM>) performs the PLMN scan for the next preferred RAT registration on the higher priority PLMN.

At operation 418b, the UE (<NUM>) determines whether the PLMN scan for the next preferred RAT registration on the higher priority PLMN is successful. Further, at operation 420b, in response to determining that PLMN scan for the next preferred RAT registration on the higher priority PLMN is successful, the UE (<NUM>) registers to the higher priority PLMN with the next preferred RAT (state C). At operation 418b, in response to determining that PLMN scan for the next preferred RAT registration on the higher priority PLMN is successful, the UE (<NUM>) continues to operate with the RPLMN which provides the <NUM> services and the <NUM> services in the dual-registration mode.

The various actions, acts, blocks, operations, or the like in the method may be performed in the order presented, in a different order or simultaneously.

<FIG> is a signal diagram illustrating a manual PLMN selection by a user when the UE (<NUM>) is in the dual registration mode, according to an embodiment of the disclosure.

Referring to <FIG>, consider that the UE (<NUM>) is dual registration capable and is registered with the RPLMN for the <NUM> services and the <NUM> services, as shown in operation <NUM>.

At operation <NUM>, the UE (<NUM>) receives a manual PLMN search request and at operation <NUM>, the UE (<NUM>) performs the PLMN scan and retrieves the list of PLMNs available. At operation <NUM>, the UE (<NUM>) provides the list of PLMNs available to the user by displaying the list on the screen of the UE (<NUM>). Further, at operation <NUM>, the UE (<NUM>) receives the PLMN select request from the user indicating that the PLMN-U is selected by the user from the list of PLMNs available.

At operation <NUM>, the UE (<NUM>) determines that the PLMN scan for the PLMN-U is successful for the <NUM> services and fails for the <NUM> services. Therefore, the UE (<NUM>) is forced to operate in the single registration mode (context in access and mobility management function (AMF) only) even though the UE (<NUM>) is dual registration capable.

<FIG> is a signal diagram illustrating a manual PLMN selection by a user when the UE (<NUM>) is in the dual registration mode, according an embodiment of the disclosure.

Referring to <FIG>, the operations <NUM> to <NUM> are substantially same and hence repeated description is omitted. At operation <NUM>, the UE (<NUM>) determines that the PLMN scan for the PLMN-U is successful for the <NUM> services and fails for the <NUM> services. Therefore, the UE (<NUM>) is forced to maintain the single registration context (only in the mobility management entity (MME)), even though the UE (<NUM>) is dual registration capable.

Therefore, in the methods and systems, when the PLMN list is indicated to the user during the manual PLMN selection procedure, and the user chooses a particular PLMN there is a possibility that the user-chosen PLMN service is available for either the N1 mode or the S1 mode thereby forcing the UE (<NUM>) to maintain the context only in one of the AMF and the MME.

<FIG> is a signal diagram illustrating the manual PLMN selection by the user when the UE (<NUM>) is in the dual registration mode, according to an embodiment of the disclosure.

<FIG> illustrates a user interface of the UE (<NUM>) which provides a list of PLMNs based on a PLMN scan, according to an embodiment of the disclosure.

Referring to <FIG> in conjunction with the <FIG> and the <FIG>, the operations <NUM> to <NUM> are substantially same and hence repeated description is omitted. However, in the proposed method, at operation <NUM>, the UE (<NUM>) while displaying the list of PLMNs based on the PLMN scan indicates the availability of the dual-registration mode for each of the PLMN in the list of PLMNs (as shown in <FIG>). Therefore, the user is able to select the PLMN which supports the dual-registration mode from the list of PLMNs, thereby avoiding using the dual-registration capable UE (<NUM>) for maintaining the context in only one of the AMF and the MME. Further, at operation <NUM>, the UE (<NUM>) receives the input indicating the selection of the PLMN-U from the list of PLMNs displayed.

At operation <NUM>, the UE (<NUM>) performs the PLMN scan for the PLMN-U successfully for both the <NUM> services and the <NUM> services. Thus operating the UE (<NUM>) in the dual registration mode.

<FIG> is a signal diagram illustrating the manual PLMN selection by the user when the UE (<NUM>) is in the dual registration mode along with providing a warning message on the selection of the PLMN, according to an embodiment of the disclosure.

Referring to <FIG> in conjunction with the <FIG>, the operations <NUM> to <NUM> are substantially same and hence repeated description is omitted. In the proposed method, when the user selects the PLMN-B which may not support the dual registration mode, at operation <NUM>, the UE (<NUM>) determines that the PLMN-B does not support the dual registration mode and provides a warning message indicating that the dual registration provided by the RPLMN is not available in the selected PLMN. Further, at operation <NUM>, the UE (<NUM>) also suggests at least one PLMN (i.e., PLMN-U) from the list of PLMNs which supports the dual registration mode. Furthermore, the user may select the PLMN-U suggested by the UE (<NUM>) and in response to the selection of the PLMN-U by the user, the UE (<NUM>) performs the PLMN scan for the PLMN-U which is successfully for both the <NUM> services and the <NUM> services. Therefore, the UE (<NUM>) operates in the dual registration mode.

The embodiments disclosed herein can be implemented through at least one software program running on at least one hardware device and performing network management functions to control the elements. The elements shown in the <FIG> include blocks, elements, actions, acts, operations, or the like which can be at least one of a hardware device, or a combination of hardware device and software module.

Claim 1:
A method for performing public land mobile network, PLMN, selection by a user equipment, UE, (<NUM>) in a dual registration mode, the method comprising:
registering, by the UE, on a registered PLMN, RPLMN, for receiving first wireless technology services, wherein the UE is dual registration capable;
detecting, by the UE, unavailability of second wireless technology services in at least one of the RPLMN and an equivalent PLMN, EqPLMN;
starting, by the UE, a periodic timer in response to detecting the unavailability of the second wireless technology services in at least one of the RPLMN and the EqPLMN; and
performing, by the UE, a PLMN selection based on a PLMN scan after an expiry of the periodic timer by performing one of:
registering to one of the RPLMN and the EqPLMN in the dual registration mode to receive the second wireless technology services, when the second wireless technology services is available in at least one of the RPLMN and the EqPLMN, and
performing another PLMN scan for the first wireless technology services and the second wireless technology services, when the second wireless technology services is unavailable in at least one of the RPLMN and the EqPLMN.