Abstract:
A method for performing manual public land mobile network (PLMN) search includes: receiving a command to perform manual PLMN search on an inactive subscription associated with a first subscriber identity module (SIM) of a communication device; determining if a data connection is enabled on an active subscription associated with a second SIM of the communication device; and if the data connection is not enabled on the active subscription, performing the manual PLMN search on the inactive subscription by tuning away from the active subscription to identify available operators associated with the first SIM.

Description:
FIELD 
       [0001]    Aspects of the present disclosure relate generally to wireless communications, and more particularly to manual public land mobile network (PLMN) search prioritization for mobile devices having multiple subscriber identity modules (SIMs). 
       BACKGROUND 
       [0002]    Wireless communication networks support communications for multiple users by sharing the available network resources. Some wireless devices are configured to facilitate communication on two separate networks via two separate subscriptions. For example, dual-Subscription Identity Module (SIM), dual standby (DSDS) devices may include two SIM cards—one card for a first subscription and a second card for a second subscription, and are capable of receiving services from two different networks. 
         [0003]    Each SIM card may correspond to a subscription with a different service provider. Further, each subscription may be associated with one or more technology types. For example, a first subscription may support 2G communication technology such as Global System for Mobile communications (GSM), while the second subscription may support one or more 3G communication technologies such as Wideband Code Division Multiple Access (WCDMA). For various reasons, for example poor call or data reception, it may be advantageous to switch from one subscription to the other subscription. 
         [0004]    Currently, multi-SIM devices do not support manual PLMN (MPLMN) search on one subscription while a data connection is active on another subscription. 
       SUMMARY 
       [0005]    Apparatuses, systems, and methods for manual PLMN search prioritization for multi-SIM mobile devices are provided. 
         [0006]    According to an aspect of the present invention there is provided a method for performing manual public land mobile network (PLMN) search. The method may include: receiving a command to perform manual PLMN search on an inactive subscription associated with a first subscriber identity module (SIM) of a communication device; determining if a data connection is enabled on an active subscription associated with a second SIM of the communication device; and if the data connection is not enabled on the active subscription, performing the manual PLMN search on the inactive subscription by tuning away from the active subscription to identify available operators associated with the first SIM. 
         [0007]    According to another aspect of the present invention there is provided a communication apparatus. The communication apparatus may include: a control unit configured to control operation of the apparatus; a communication unit configured to transmit and receive radio frequency (RF) communication signals; a first subscriber identity module (SIM) containing identification information for a first communication network; a second SIM containing identification information for a second communication network; an interface device comprising an input device configured to receive a command to perform manual public land mobile network (PLMN) search on an inactive subscription associated with one of the first SIM and the second SIM; and a determination unit configured to determine whether a data connection is enabled on an active subscription associated with the other of the first SIM and the second SIM. 
         [0008]    According to another aspect of the present invention there is provided a communication system. The communication system may include: a first communication network; a second communication network; a communication device including: a first subscriber identity module (SIM) containing identification information for the first communication network; a second SIM containing identification information for the second communication network; an interface device comprising display device and an input device configured to receive a command to perform manual public land mobile network (PLMN) search on an inactive subscription associated with one of the first SIM and the second SIM; and a control unit configured to control operation of the communication device. 
         [0009]    Other features and advantages of the present inventive concept should be apparent from the following description which illustrates by way of example aspects of the present inventive concept. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0010]    Aspects and features of the present inventive concept will be more apparent by describing example embodiments with reference to the accompanying drawings. 
           [0011]      FIG. 1  is a block diagram illustrating a mobile device according to an example embodiment of the present inventive concept. 
           [0012]      FIG. 2  is a flowchart illustrating operation of a DSDS mobile device during MPLMN search according to an example embodiment of the present inventive concept. 
       
    
    
     DETAILED DESCRIPTION 
       [0013]    While certain embodiments are described, these embodiments are presented by way of example only, and are not intended to limit the scope of protection. The apparatuses, methods, and systems described herein may be embodied in a variety of other forms. Furthermore, various omissions, substitutions, and changes in the form of the example methods and systems described herein may be made without departing from the scope of protection. 
         [0014]      FIG. 1  is a block diagram illustrating a DSDS mobile device according to an example embodiment of the present inventive concept. As illustrated in  FIG. 1 , a mobile device  100  may include a control unit  110 , a communications unit  120 , an antenna  130 , a first SIM  140 , a second SIM  150 , a switch unit  160 , an interface device  170 , and storage  180 . The mobile device  100  may be, for example but not limited to, a mobile telephone, smartphone, tablet, computer, etc., capable of mobile communications with one or more wireless networks. 
         [0015]    Referring to  FIG. 1 , the communication unit  120  transmits and receives radio frequency (RF) signals to and from wireless communication networks through the antenna  130 . The first SIM  140  and the second SIM  160  contain subscriber identification information for network service subscriptions and are electrically connected to the control unit  110  through the switch unit  160 . The switch unit  160  is configured to electrically connect the first SIM  140 , the second SIM  160 , or both the first and second SIM to the control unit  110 . 
         [0016]    The first and second SIMs  140 ,  150  each contain data necessary to subscribe the mobile device  100  to a communication network. For example, the first SIM  140  may subscribe the mobile device  100  with communication network A and the second SIM  150  may subscribe the mobile device  100  with communication network B. In some example embodiments, mobile devices may have more than two SIMs and may be capable of accessing services from more than two different networks. 
         [0017]    Communication networks A and B may be operated by the same or different service providers, and/or may support the same or different technologies, for example, but not limited to, WCDMA and GSM. One of ordinary skill in the art will appreciate that any available combination of technologies and service providers will fall within the scope of the present inventive concept. 
         [0018]    The control unit  110  controls overall operation of the mobile device  100  including control of the communications unit  120 , switch unit  160 , interface device  170 , and storage  180 . The control unit  110  may be a programmable device, for example, but not limited to, a microprocessor or microcontroller. The control unit  110  may include a determination unit  112  which determines whether a data connection is enabled on an active subscription. Alternatively, the determination unit  112  may be implemented as electronic circuitry separate from the control unit  110 . The control unit  110  may control the switch unit  160  to select the first SIM  140  or the second SIM  150  based on which subscription is active. The storage  180  may store application programs necessary for operation of the mobile device  100  that are executed by the control unit  110 , as well as application data and user data. 
         [0019]    The interface device  170  may include an input device  172  and a display device  174 . The input device  172  may be, for example, but not limited to, a keypad and/or a touch screen. The display device  174  may be, for example, but not limited to, a liquid crystal display (LCD). One of ordinary skill in the art will appreciate that other input and display devices may be used without departing from the scope of the present inventive concept. 
         [0020]      FIG. 2  is a flowchart illustrating operation of a DSDS mobile device during manual PLMN search according to an example embodiment of the present inventive concept. In the example illustrated in  FIG. 2 , subscription 1 is the active subscription and subscription 2 is the inactive subscription. Accordingly, in this example manual PLMN search is performed on subscription 2. One of ordinary skill in the art will appreciate that manual PLMN search may also be performed on subscription 1 when subscription 2 is the active subscription. 
         [0021]    Referring to  FIG. 2 , the mobile device  100  receives a command to initiate manual PLMN search on the inactive subscription ( 215 -Y). A determination is made whether a data connection is enabled on the active subscription, i.e., subscription 1 ( 220 ). The determination may be made by the determination unit  112  by monitoring data traffic on the active subscription or by any other suitable method known to those of ordinary skill in the art. If a data connection is not enabled on subscription 1 ( 220 -N), the control unit  110  controls the communication unit  120  to perform manual PLMN search on subscription 2 ( 225 ). 
         [0022]    During manual PLMN search, tune away is performed on subscription 2 and channel data, for example, but not limited to, signal strength and quality of service (QoS) data, as well as operator information of available operators associated with subscription 2 is received by the mobile device  100  ( 230 ). In an example embodiment, received signal strength (RSSI) on the bands supported by Subscription 2 may be calculated, and acquisition on the top few absolute radio frequency channel numbers (ARFCNs) attempted. If acquisition is successful, operator information including mobile country code (MCC), mobile network code (MNC), operator name, and whether or not that PLMN is forbidden may be obtained. 
         [0023]    Upon successful completion of the manual PLMN search, a list of available operators associated with subscription 2 is returned and displayed on the display device  174  of the interface device  170  ( 240 ). The list of available operators may be displayed in rank order of, for example, but not limited to, QoS, strength of signal, etc. 
         [0024]    If the determination unit  112  determines that the data connection is enabled on subscription 1 ( 220 -Y), the control unit  110  initiates manual PLMN search on subscription 2 ( 245 ) and the data call on subscription 1 is disconnected ( 250 ). A determination is made by the control unit  110  whether the user stays on the same user interface (UI) from which the manual PLMN search is initiated or switches to other web activities while waiting for the manual PLMN search results ( 255 ). 
         [0025]    If the user stays on the same UI from which the manual PLMN search is initiated ( 255 -Y), the control unit  110  controls the communication unit  120  to perform the manual PLMN search on subscription 2 ( 260 ). During manual PLMN search, tune away is performed on subscription 2 and channel data, for example, but not limited to, signal strength and QoS data, as well as operator information for available operators associated with subscription 2 is received by the mobile device ( 265 ). In an example embodiment, received signal strength (RSSI) on the bands supported by Subscription 2 may be calculated, and acquisition on the top few ARFCNS attempted. If acquisition is successful, operator information including MCC, MNC, operator name, and whether or not that PLMN is forbidden may be obtained. 
         [0026]    Upon successful completion of the manual PLMN search, a list of available operators is returned and displayed on the display device  174  of the interface device  170  ( 270 ), and the data call on subscription 1 is reestablished ( 275 ). The list of available operators may be displayed in rank order of, for example, but not limited to, QoS, strength of signal, etc. 
         [0027]    If while waiting for manual PLMN search results the user moves on to other web activities, for example, but not limited to, web browsing or gaming ( 255 -N), the control unit  110  reestablishes the data call on subscription 1 ( 280 ), and controls the communication unit  120  to perform the manual PLMN search and data transmission and reception on the subscription 1 data call in parallel ( 285 ). Parallel execution of the subscription 1 data call and the manual PLMN search may result in somewhat lower performance of the mobile device  100  during the parallel execution. 
         [0028]    During manual PLMN search, tune away is performed on subscription 2 and channel data, for example, but not limited to, signal strength and QoS data, as well as operator information of available operators associated with subscription 2 is received by the mobile device ( 290 ). In an example embodiment, received signal strength (RSSI) on the bands supported by Subscription 2 may be calculated, and acquisition on the top few ARFCNS attempted. If acquisition is successful, operator information including MCC, MNC, operator name, and whether or not that PLMN is forbidden may be obtained. 
         [0029]    Upon successful completion of the manual PLMN search, a list of available operators associated with subscription 2 is returned and a pop-up graphic is displayed on the display device  174  of the interface device  170  and provides an option to switch the UI display to view the results of the manual PLMN search ( 295 ). If the user elects to view the list, the list of available operators may be displayed in rank order of, for example, but not limited to, QoS, strength of signal, etc. Operators may also be listed in order of home PLMN (HPLMN), preferred PLMNs, then forbidden PLMNs. 
         [0030]    While certain embodiments have been described, these embodiments have been presented by way of example only, and are not intended to limit the scope of the protection. The apparatuses, methods, and systems described herein may be embodied in a variety of other forms. Various omissions, substitutions, and/or changes in the form of the example apparatuses, methods, and systems described in this disclosure may be made without departing from the spirit of the protection. 
         [0031]    The accompanying claims and their equivalents are intended to cover such forms or modifications as would fall within the scope and spirit of the protection. For example, the example apparatuses, methods, and systems disclosed herein can be applied to multi-SIM mobile devices subscribing to multiple communication networks and/or communication technologies. The various components illustrated in the figures may be implemented as, for example, but not limited to, software and/or firmware on a processor, ASIC/FPGA/DSP, or dedicated hardware. Also, the features and attributes of the specific example embodiments disclosed above may be combined in different ways to form additional embodiments, all of which fall within the scope of the present disclosure. 
         [0032]    Although the present disclosure provides certain example embodiments and applications, other embodiments that are apparent to those of ordinary skill in the art, including embodiments which do not provide all of the features and advantages set forth herein, are also within the scope of this disclosure. Accordingly, the scope of the present disclosure is intended to be defined only by reference to the appended claims.