System and methods for using wireless network correlations to acquire service on a multi-SIM device

Methods and devices are disclosed for enabling efficient service acquisition on multiple SIMs of a multi-SIM device. After at least one SIM has maintained or reacquired a network connection, the wireless device may identify that network, access a joint acquisition database, and determine whether there is a correlated network entry showing a network from which service may be received on SIM-2. In this manner, the wireless device may automatically prioritize a network for a recovery scan on SIM-2, thereby overriding conventional priority given to the network that was most-recently-used by SIM-2.

BACKGROUND

Wireless communications devices may undergo various system acquisition processes in attempting to connect to a system. For example, a wireless device may scan the air interface for radio frequencies corresponding to particular networks. Such networks may be determined based on any of a number of prioritization schemes, such as based on recency of use, preference set forth by the service provider, etc. In a typical arrangement, an acquisition table may store acquisition information for the preferred networks of the service provider, with information for those networks to which the device recently connected being further stored in a most-recently-used table or list.

Multi-SIM wireless devices have become increasing popular because of their flexibility in service options and other features. One type of multi-SIM wireless device, a dual-SIM dual active (DSDA) device, allows simultaneous active connections with the networks corresponding to two SIMs. DSDA devices typically have separate transmit/receive chains associated with each SIM. Another type of multi-SIM wireless device, a dual-SIM dual standby (DSDS) device, allows selective communication on a first network while listening for pages on a second network. In various types of multi-SIM devices, each modem stack associated with a subscription may store its own acquisition preferences, such as using acquisition tables and most-recently used tables, and may independently perform service acquisition. Consequently, the modem stack associated with each SIM may independently scan the air interface for channels according to its own prioritization, which may prolong recovery time and/or consume a large amount of power.

SUMMARY

Systems, methods, and devices of the various embodiments enable a multi-SIM device to acquire wireless network service from on both a first and second subscription by connecting to a first wireless network on the first SIM, in which the first wireless network is associated with the first subscription, determining whether the connection to the first wireless network is correlated with a second wireless network that is accessible to the second subscription, and performing a service acquisition scan on the second SIM using acquisition data associated with the second network in response to determining that the connection to the first network is correlated with a second network that is accessible to the second subscription.

In embodiment systems, methods and devices, determining whether the connection to the first network is correlated with a second network that is accessible to the second subscription may include identifying acquisition data associated with the first network, accessing a joint acquisition database on the multi-SIM device in which the joint acquisition database includes network entries for the first SIM and network entries for the second SIM, in which each network entry represents a wireless network, identifying a network entry for the first SIM containing the acquisition data associated with the first network, and determining whether the network entry for the first SIM is part of a correlation record containing a network entry for the second SIM. In an embodiment, a network entry for the second SIM may identify information including a type of wireless communication technology used to access the second wireless network, a band of radio frequencies encompassing frequencies for communicating on the second wireless network, and at least one channel corresponding to at least one frequency on which the second subscription can access the second wireless network.

Embodiment methods may also include updating a joint acquisition database on the multi-SIM wireless device by identifying a first wireless network providing service to a first SIM, identifying acquisition parameters associated with the first wireless communication network, saving a first network entry for the first SIM in the joint acquisition database in which the first network entry comprises an identification of the first wireless network and the acquisition parameters associated with the first wireless network, determining whether a second wireless network is providing service to the second SIM, and creating a correlation record in response to determining that the second wireless network is providing service to the second SIM.

In embodiment systems, methods and devices, identifying acquisition parameters associated with the second wireless network may include receiving information from a baseband-RF resource chain associated with the second SIM in which the received information corresponds to information broadcast by the second wireless network.

DETAILED DESCRIPTION

The terms “wireless device,” “wireless communications device,” and “mobile device” are used interchangeably herein to refer to any one or all of cellular telephones, smart phones, personal or mobile multi-media players, personal data assistants (PDAs), laptop computers, tablet computers, smart books, palm-top computers, wireless electronic mail receivers, multimedia Internet enabled cellular telephones, wireless gaming controllers, and similar personal electronic devices that include a programmable processor and memory and circuitry for establishing wireless communication pathways and transmitting/receiving data via wireless communication pathways.

As used herein, the terms “SIM”, “SIM card” and “subscriber identification module” are used interchangeably to mean a memory that may be an integrated circuit or embedded into a removable card, which stores an International Mobile Subscriber Identity (IMSI), related key, and/or other information used to identify and/or authenticate a wireless device on a network. The term SIM may also be used as shorthand reference to a communication network associated with a particular SIM, since the information stored in a SIM enables the wireless device to establish a communication link with a particular network, thus the SIM and the communication network correlate to one another.

As used herein, the terms “multi-SIM device,” “multi-SIM wireless device” “dual-SIM device” “dual-SIM dual active device” and “DSDA device” are used interchangeably to describe a wireless device that is configured with more than one SIM and is capable of independently handling communications with networks of all subscriptions.

As used herein, the terms “system preference list,” “preferred roaming list,” “PRL,” “public land mobile network list,” and “PLMN” are used interchangeably to describe a data structure that identifies, and prioritizes, home networks and roaming partners of the home carrier associated with a wireless device and/or subscription on a wireless device.

In recent years, use of wireless communications devices for voice telephone services, email or text messaging services and even multi-media services has become commonplace, among mobile professionals and throughout the more general consumer population. To support broad customer's efficient acquisition of mobile communication networks, many wireless devices today are capable of using various networks and even different network technologies in many different regions, and increasingly, in different countries.

For the efficient acquisition of wireless communications networks, wireless service carriers have standardized a number of techniques for selecting wireless communications systems in geographic regions and obtaining service therefrom, in accordance with preferences of the subscriber's service provider/carrier. The local wireless communications systems may also support different multiple-access wireless communications protocols such as code division multiple access (CDMA), wideband CDMA (WCDMA), Advanced Mobile Phone Service (AMPS), Global System for Mobile communications (GSM), General Packet Radio Services (GPRS) or High Data Rate (HDR) technology (e.g., 1×EV technology).

In operation, a conventional wireless device may select and attempt to acquire service on at least one of the available wireless communications systems. To assist with the selection of a desirable system, a wireless device may typically store a system preference list that identifies wireless communications systems that are compatible with the wireless device, and acquisition parameters (e.g., band, frequency and mode) for the systems listed therein.

Within a system preference list, the wireless communications systems may be grouped by geographic region and sorted from the most desirable to the least desirable system in each region. The system preference list may be maintained by the wireless device's wireless services provider through over-the-air signaling and periodic downloads of updated systems data. By controlling the content of the systems table, the wireless device's wireless services provider may establish an order of priority among the listed systems that steers the system selection process.

A wireless device may implement a variety of acquisition procedures to determine how and when networks in a system preference list (i.e., a PRL or PLMN list) may be selected. For example, in a common system selection and acquisition procedure, the wireless device may first attempt to acquire service on the networks that were most recently used by the wireless device. A most-recently-used table may store one or more data values associated with each network on which the wireless device most recently obtained service. Such data values may include, for example, a type of wireless communication technology (i.e., mode), a range of radio frequencies (i.e., band), and identification(s) of specific frequencies (i.e., channel(s)) used to communicate with the network.

The wireless device may step through the networks listed in the most-recently-used table, such as by scanning available frequencies in the vicinity of the wireless device, until acquisition is successful. If the wireless device cannot obtain an available network using the most-recently-used table, the wireless device may perform a more extensive search based on the PRL or PLMN list. Once the device acquires service on a new network, the network may be added as a new entry in the most-recently-used table for future use. In this manner, most-recently-used data may be compiled over time from systems selected based on the carrier's system preference list (PRL or PLMN). While in some cases recency of use may provide a reasonable approximation of the networks that may be presently available for connection, in other cases the recency of use does not reflect the available systems in the present area of the device. For example, a wireless device may have moved from an area where it was powered off or disconnected from one system, to another area in which the available systems are different.

Various wireless devices may be configured to support multiple SIMs, each of which may be associated with the same or different service providers/communications systems. Accordingly, each subscription in a multi-SIM device may be associated with its own system data and acquisition data, such as in a system preference list (e.g., a PRL or a PLMN list). Further, although a multi-SIM device may be configured to share resources among different SIMs, communications on each subscription may still be implemented by separate modem stacks. Each SIM may also be associated with a separate list of most-recently-used networks, and perform an independent acquisition scan according to its own preference data. In multi-SIM devices that are configured with a shared radio resource, acquisition scans may necessarily be performed for each SIM one at a time, thereby prolonging service recovery time. In multi-SIM devices with separate radio resources for each SIM, acquisition scans may be performed simultaneously, a process that may consume a large amount of power in order to recover service on both SIMs.

In the various embodiments, service acquisition may be improved on a multi-SIM device by using inherent co-location of service provider cellular sites that support the various SIMs in the same geographical area. Specifically, instead of using the recency of previous network connections on a SIM as a starting point for reacquiring service on that SIM, the various embodiments may use correlation records that link previous network connections on one SIM with current network connections on a different SIM. Since SIMs within the same device are necessarily co-located in the same geographical area, and cellular networks feature cells of limited range, a current network on the second SIM may provide a more accurate indication of present location for the SIM attempting to recover service. In this manner, a correlation with the second SIM in may provide a better indication of the network from which the first SIM has a highest probability of receiving service in the present location.

The various embodiments may be implemented in a joint acquisition database. The joint acquisition database may be used to link service information for networks to which different subscriptions may be simultaneously connected. The joint acquisition database may store, in device memory, information about the coexisting network connections, as well as correlation records thereof. In this manner, in an out-of-service wireless device, once one of the SIMs reacquires service on a network, the remaining SIMs may automatically attempt to acquire service on their respective coexisting networks in the joint acquisition database. As a result, the amount of time that it may take for all SIMs on a device to establish service on their respective networks may be minimized.

FIG. 1illustrates a wireless network system100suitable for use with the various embodiments. Wireless devices102,104may be configured to establish wireless connections with cell towers or base stations of one or more radio access networks. For example, wireless devices102,104may transmit/receive data using base stations106,108, which may be part of a network110, as is known in the art. Wireless device102may further be configured to transmit/receive data through base station112, which may be part of a different network114.

The wireless networks110,114may be cellular data networks, and may use channel access methods including, but not limited to, Frequency Division Multiple Access (FDMA), Time Division Multiple Access (TDMA), Code Division Multiple Access (CDMA), Universal Mobile Telecommunications Systems (UMTS) (particularly, Long Term Evolution (LTE)), Global System for Mobile Communications (GSM), Wi-Fi, PCS, G-3, G-4, or other protocols that may be used in a wireless communications network or a data communications network. Networks110,114may use the same or different wireless interfaces and/or physical layers. In an embodiment, base stations106,108,112may be controlled by one or more base station controllers (BSC)116,118. For example, base stations106,108, BSC116, and other components may form network110, as is known in the art. Alternate network configurations may also be used and the embodiments are not limited to the configuration illustrated. For example, in another embodiment the functionality of the BSC116and at least one of base stations106,108may be collapsed into a single “hybrid” module having the functionality of these components.

In the various embodiments, a wireless device102may simultaneously access core networks120,122after camping on cells managed by base stations106,112. Wireless device102may also establish connections with Wi-Fi access points, which may connect to the Internet. While the various embodiments are particularly useful with wireless networks, the embodiments are not limited to wireless networks and may also be implemented over wired networks with no changes to the methods.

In wireless network system100, wireless device102may be a multi-SIM device that is capable of operating on a plurality of SIMs. For example, the wireless device102may be a dual-SIM device. Using dual-SIM functionality, the wireless device102may simultaneously access two core networks120,122by camping on cells managed by base stations106,112. Core networks120,122may be interconnected by public switched telephone network (PSTN)124, across which the core networks120,122may route various incoming and outgoing communications to the wireless device102.

The wireless device102may make a voice or data call to a third party device, such as wireless device104, using one of the SIMs. The wireless device102may also receive a voice call or other data transmission from a third party. The third party device (e.g., wireless device104) may be any of a variety of devices, including, but not limited to, a mobile phone, laptop computer, PDA, server, etc.).

Some or all of the wireless devices102may be configured with multi-mode capabilities and may include multiple transceivers for communicating with different wireless networks over different wireless links/radio access technologies (RATs). For example, a wireless device102may be configured to communicate over multiple wireless data networks on different subscriptions, such as in a dual-SIM wireless device. In particular, a wireless device102may be configured with dual-SIM dual active (DSDA) capability, which enables a dual-SIM device to simultaneously participate in two independent communications sessions, generally though independent transmit/receive chains.

For clarity, while the techniques and embodiments described herein relate to a wireless device configured with at least one CDMA subscription, they may be extended to subscriptions on other radio access networks (e.g., GSM, UMTS, WCDMA, LTE, etc.).

FIG. 2is a functional block diagram of a multi-SIM wireless device200that is suitable for implementing the various embodiments. Wireless device200may include a first SIM interface202a, which may receive a first identity module SIM-1204athat is associated with the first subscription. The wireless device200may also include a second SIM interface202b, which may receive a second identity module SIM-2204bthat is associated with the second subscription.

A SIM in the various embodiments may be a Universal Integrated Circuit Card (UICC) that is configured with SIM and/or USIM applications, enabling access to GSM and/or UMTS networks. The UICC may also provide storage for a phone book and other applications. Alternatively, in a CDMA network, a SIM may be a UICC removable user identity module (R-UIM) or a CDMA subscriber identity module (CSIM) on a card.

Each SIM card may have a CPU, ROM, RAM, EEPROM and I/O circuits. A SIM used in the various embodiments may contain user account information, an international mobile subscriber identity (IMSI), a set of SIM application toolkit (SAT) commands and storage space for phone book contacts. A SIM card may further store home identifiers (e.g., a System Identification Number (SID)/Network Identification Number (NID) pair, a Home Public-Land-Mobile-Network (HPLMN) code, etc.) to indicate the SIM card network operator provider. An Integrated Circuit Card Identity (ICCID) SIM serial number may be printed on the SIM card for identification.

Wireless device200may include at least one controller, such as a general processor206, which may be coupled to a coder/decoder (CODEC)208. The CODEC208may in turn be coupled to a speaker210and a microphone212. The general processor206may also be coupled to at least one memory214. Memory214may be a non-transitory tangible computer readable storage medium that stores processor-executable instructions. For example, the instructions may include routing communication data relating to the first or second subscription though a corresponding baseband-RF resource chain. The memory214may store operating system (OS), as well as user application software and executable instructions. The memory214may also store a systems database, which may contain a system preference list (i.e., PRL or PLMN list) and a joint acquisition database, as described in further detail below with reference toFIG. 3.

The general processor206and memory214may each be coupled to at least one baseband modem processor216. Each SIM in the wireless device200(e.g., SIM-1202aand SIM-2202b) may be associated with a baseband-RF resource chain. A baseband-RF resource chain may include baseband modem processor216, which may perform baseband/modem functions for communications on at least one SIM, and may further include one or more amplifiers and radios, referred to generally herein as RF resource218. RF resource218may perform transmit/receive functions for at least one SIM of the wireless device. In an embodiment, RF resource218may include separate transmit and receive circuitry, or may include a transceiver that combines transmitter and receiver functions. The RF resource218may be coupled to a wireless antenna (e.g., a first wireless antenna220aand a second wireless antenna220.

In one embodiment, the wireless device200may have a common baseband-RF resource chain for all SIMs in the wireless device (i.e., a single baseband modem processor216and a single RF resource218). In another embodiment, different SIMs may be associated with separate baseband-RF resource chains that include physically or logically separate RF resources (i.e., RF1, RF2), each of which may be coupled to a common baseband modem processor216(i.e., a single device that performs baseband/modem functions for all SIMs on the wireless device). Alternatively, different SIMs may be associated with separate baseband-RF resource chain that also include physically or logically separate baseband modem processors (e.g., BB1, BB2).

The at least one memory214of the wireless device200may store an operating system (OS) and user application software. In a particular embodiment, the general processor206, memory214, baseband processor(s)216, and RF resource218may be included in a system-on-chip device222. The first and second SIMs204a,204band their corresponding interfaces202a,202bmay be external to the system-on-chip device222. Further, various input and output devices may be coupled to components of the system-on-chip device222, such as interfaces or controllers. Example user input components suitable for use in the wireless device200may include, but are not limited to, a keypad224and a touchscreen display226.

In an embodiment, the keypad224, touchscreen display226, microphone212, or a combination thereof, may perform the function of receiving the request to initiate an outgoing call. For example, the touchscreen display226may receive a selection of a contact from a contact list or receive a telephone number. In another example, either or both of the touchscreen display226and microphone212may perform the function of receiving a request to initiate an outgoing call. For example, the touchscreen display226may receive selection of a contact from a contact list or to receive a telephone number. As another example, the request to initiate the outgoing call may be in the form of a voice command received via the microphone212. Interfaces may be provided between the various software modules and functions in wireless device200to enable communication between them, as is known in the art.

FIG. 3illustrates a systems database300that may be used to store information describing available wireless networks in an example dual-SIM device. In a memory214of wireless device200, a systems database300may include both volatile and nonvolatile random access memory, and may be configured to store to store both programmable and accumulated acquisition information for service on the multiple SIMs (e.g., SIM-1 and SIM-2). Such programmable acquisition information may include system preference lists302a,302bassociated respectively with SIM-1 and SIM-2. In the embodiments, each systems preference list may also be organized into different data structures. For example, SIM-1 may be configured to access CDMA-type networks, and system preference list302amay therefore be a PRL that may be subdivided as a systems table304and acquisition table306. While this example associated with SIM-1 refers to a PRL, such reference merely provides an example of a system preference list, and is not intended to limit the embodiments to any particular service or type of access network.

As may be known to those of ordinary skill in the art, the systems table304may provide a prioritized list of communication networks that the wireless device may access using SIM-1, grouped by geographic areas (GEOs). Each network in the systems table304may have fields to store information including the SID/NID pair that identifies the network, an indicator of relative priority of each network in terms of connection desirability, and an index that corresponds to the acquisition table306. In other embodiments, the wireless communications systems listed in the systems table304may be identified using other system identifiers, such as a unique band, mode and frequency, an Internet Protocol Version 6 (IPv6) address or PLMN identifier.

For each network listed in the systems table304, an acquisition table306may provide various acquisition parameters. Such acquisition parameters may include, but are not limited to, mode, frequency band, and channels on which the associated SIM may search to gain service on the network. In various embodiments, the channels may be identified as a channel block, or by specific channel numbers. In the various embodiments, the acquisition table306may also list networks and their respective acquisition parameters in order of highest priority, which may be based on relative recency of connection.

The system preference lists302a,302bmay be updated periodically by the service providers associated with SIM-1 and SIM-2, for example, through over-the-air provisioning (OTAP) servers308a,308b. In the various embodiments, alternative configurations for the system preference list302a,302b, the systems table304and the acquisition table306, and alternative identification and acquisition parameters may be used in accordance with the various embodiments.

The various embodiments may improve service acquisition operations on multiple SIMs by implementing a joint acquisition database310in systems database300. In particular, the joint acquisition database310may store accumulated acquisition data from previous network connections in a joint acquisition database310. When recovering from loss of service or power on one or more SIM, the joint acquisition database310in the various embodiments may provide the wireless device with a mechanism for overriding the selection of a most-recently-used network on one SIM if another SIM has maintained or reacquired service. In an embodiment, the joint acquisition database310may be stored in non-volatile memory in order to remain available on the wireless device following shutting down/restarting the device.

The accumulated acquisition data stored in joint acquisition database310may be in the form of correlation records linking previous network acquisitions across different SIMs in the device. In an embodiment, joint acquisition database310may be provided in a most-recently-used priority order, which may serve as a default for system selection, as explained in further detail below. The information provided for each network associated with SIM-1 and SIM-2 in the joint acquisition database310may be of the same or similar type as provided for the networks associated with SIM-1 in the acquisition table306, discussed above. For example, the joint acquisition database310may provide a mode, a frequency band, and/or channel(s) of the various networks associated with SIM-1 and SIM-2. Therefore, in some embodiments the joint acquisition database310may replace all or part of the acquisition table306(or analogous data structure) in the system preference lists302a,302b.

In the various embodiments, the joint acquisition database310may be accessible to all SIMs on a multi-SIM device, and may send information to, and receive information from, the baseband-RF chain(s)312associated with each SIM. In this manner, the acquisition information may be accumulated from networks on which the wireless device achieves service and used to update and/or generate correlation records in the joint acquisition database310. Further, the joint acquisition database310may be used to instruct each SIM as to which channels/frequencies should be scanned in an attempt to acquire service.

Generating a joint acquisition database in the various embodiments may involve determining and storing records of correlations between networks on which service has been simultaneously acquired on multiple SIMs. Acquiring service using the generated joint acquisition database may use the correlation records to determine a priority network from which service may be requested on the SIM in the future. In an embodiment, the joint acquisition database may store information about the most-recently used networks for all of the SIMs, which may be used to determine subsequent priority between networks in case an attempt to gain service on the correlated network fails.

FIG. 4illustrates an example joint acquisition database400that may be implemented on a dual-SIM wireless device. In database400, network entries may provide acquisition information for connecting to the networks available on each SIM. For example, network entries associated with a first SIM (i.e., SIM-1) may be stored in a first portion402aof the database400, while network entries associated with the second SIM (i.e., SIM-2) may be separately stored in a second portion402b.

Example fields that may be provided in the network entries may include, for example, information about the mode (e.g., CDMA, EV-DO, AMPS, WiMax, etc.), frequency band (e.g., PCS, cellular, etc.), and channel(s) associated with the frequencies for communicating with the network of the carrier (e.g., channel block, channel identification number, etc.). Such information may be provided in any of a number of different arrangements of data fields within the network entries. Further, the values shown in the network entries inFIG. 4Aare provided merely as examples, and are not meant to limit the various data types or values that may be included in the network entries.

In an embodiment, a correlation record404may be formed based on network entries that share a common row across portions402a,402b. In the various embodiments, if a wireless device has maintained service on SIM-1, or has reacquired service in normal operation on SIM-1 (i.e., scanning frequencies of most-recently-used network, etc.) the wireless device may access a correlation record in the joint acquisition database400to automatically determine which acquisition parameters should be prioritized for attempting reacquisition of service on SIM-2. Specifically, an example dual-SIM device may identify a network providing service on SIM-1, locate a network entry in portion402athat represents the network of SIM-1, and, using a correlation record404, identify a correlated network entry for SIM-2 in portion402b. Thereafter, the wireless device may attempt to acquire service on SIM-2 by scanning the channels indicated in the correlated network entry, thereby avoiding traversing a list of most-recently used networks for SIM-2.

The network entries in portions402a,402bmay be provided in order of most recent use on the corresponding subscription (i.e., SIM-1, SIM-2), and may be associated with a priority index406. For example, the first row in the joint acquisition database400may be associated with an index of “0”, representing that the network entries in this first row correspond to the most-recently used networks on SIM-1 and SIM-2, respectively. Thus, if the wireless device cannot acquire service on SIM-2 through the network indicated in the correlation record404, the wireless device may, as a default option, attempt to acquire service on the most-recently-used network listed for SIM-2 per normal operation, as discussed above.

System acquisition on multiple SIMs based on previous correlation occurrences may not be reciprocal in some cases, such as due to different working ranges of cell sites associated with different networks. For example, a correlation record may provide that when SIM-1 is receiving service on a first network (“Network 1”), SIM-2 should attempt to acquire service on a second network (“Network 2”). However, the correlation record may further provide that when SIM-2 is receiving service on Network 2, SIM-1 should attempt to acquire service on a third network (“Network 3”), as opposed to Network 1. Therefore, multiple network entries may be provided for at least one SIM according to an alternative embodiment. To account for these differences across the SIMs, in various embodiments correlation records may provide additional details that further improve accuracy and usefulness of the system.

FIG. 4Billustrates an example detailed correlation record450that may be included in the joint acquisition database400according to an embodiment. In this example, correlation record450may provide one network entry452for SIM-2 and two network entries454a,454bfor SIM-1. In order for a processor of the wireless device to properly “read” correlation record450, indicators456a,456b. . .456nmay be included to show the direction of links for the multiple network entries. Thus, if receiving service on SIM-2 from the network associated with network entry452, the wireless device may access the correlation record450and use the indicators456a,456bto identify a correlated network for SIM-1. That is, although SIM-1 may be associated with multiple network entries454a,454b, based on the direction of indicator456bthe wireless device may select the proper network entry454band attempt to acquire service from its associated network.

A wireless device according to the various embodiments may be configured to operate on multiple systems corresponding to multiple SIMs, as discussed above. For each system, the wireless device may attempt to acquire service on an appropriate network using a joint acquisition database such as joint acquisition database400discussed above. In some situations, such as following powering-on or resetting the device, bringing the device into a coverage area of a new network, activating the device for the first time, etc., one or more SIMs may be forced to acquire service on a new network using RF scanning and measurement in conjunction with a systems preference list (i.e., PRL or PLMN list). In various embodiments, a wireless device may use the detected connections on such new networks to generate additional correlation records in the joint acquisition database.

FIG. 5illustrates an embodiment method500of updating or creating a joint acquisition database by generating additional correlation records. The operations of method500may be implemented by one or more processors of the wireless device, such as the general processor206shown inFIG. 2, or a separate controller (not shown) that may be coupled to memory and to the baseband modem processor(s)216.

In block502, the wireless device processor may detect that a first SIM (i.e., SIM-1) has acquired service on a new network, or a network that has not recently provided service to SIM-1. This may be determined, for example, by software and/or separate circuitry configured to perform acquisition control functions. In an example embodiment, a joint acquisition control module of the wireless device processor may monitor current service conditions on each SIM and/or compare network connections to those already listed in the joint acquisition database.

In block504, the wireless device processor may identify acquisition information for the new network based on information broadcast by its base station and/or information from the RF resource associated with SIM-1. Acquisition information for a CDMA-type (i.e., 1xRTT/EVDO access) network may include, for example, a SID/NID pair, frequency band, channel (or channel block), and/or a GEO. Identifying information for a GSM-type (i.e., GERAN/UTMS/LTE access) network may include, for example, a mobile country code (MCC), mobile network code (MNC), and/or a location area identity (LAI).

In block506, the wireless device processor may create a new network entry i for the new network on SIM-1 in the joint acquisition database (i.e., in portion402aof database400). In an embodiment, the new entry may include the parameters included in each network entry of joint acquisition database400, discussed above with reference toFIG. 4(i.e., index number, mode, band, channel(s), etc.). In an embodiment, the joint acquisition database may maintain the various correlation records in a default order of most-recent use. Thus, the new network entry may be automatically assigned a top index number (i.e., “0”). In determination block508, the wireless device processor may determine whether the wireless device is currently receiving service from a network on SIM-2. If the wireless device is not receiving service on SIM-2 (i.e., determination block508=“No”), the completed new network entry may be stored in the joint acquisition database without further information in block510. The process may return to block502for monitoring current service conditions on each SIM, and may repeat upon detecting a new network on one or more SIM.

If the wireless device is receiving service on SIM-2 (i.e., determination block508=“Yes”), in block512the wireless device processor may identify acquisition information for the network that is serving SIM-2. In block514, the wireless device processor may use the acquisition information identified in block512to create a corresponding network entry for SIM-2.

In block516, the new network entry for SIM-1 and the corresponding network entry for SIM-2 may be stored as a correlation record in the joint acquisition database. In one example, storing the correlation record may involve directly storing the acquisition information for the network on SIM-2 in a database entry. In other embodiments, a pointer to such information may be incorporated into the correlation record, which may obtain existing network information from a different correlation record and/or different network entries in the joint acquisition database. In another embodiment, acquisition information may be copied from existing network entries and/or records in the joint acquisition database for inclusion in the new correlation record. The wireless device processor may return to block502to monitor service acquisition on both SIMs, and may repeat process500upon detecting service on a new network for at least one of the SIMs.

FIG. 6illustrates an embodiment method600for acquiring service on multiple SIMs using the joint acquisition database. In block602of method600, a wireless device processor may detect that the wireless device has lost and is attempting to reacquire service on at least one SIM. For example, on a dual-SIM device, one of the SIMs may have lost service with its network due to movement of the wireless device and coverage boundaries established by the wireless service provider of that network. In another example, both SIMs may have lost service due to the wireless device being reset or powered off.

In block604, the wireless device processor may detect that the wireless device has recovered or maintained service on at least one, but less than all, SIMs. For example, on a dual-SIM device in which only one SIM lost service, the wireless device processor may detect that the other SIM (e.g., first SIM/SIM-1) has maintained its service connection with a network. Alternatively, on a dual-SIM device on which both SIMs lost service, one of the SIMs (e.g., SIM-1) may recover service as either the first to gain control of and use a shared radio for both SIMs, or as the first to complete an acquisition scan separate radios for each SIM.

In block606, the wireless device processor may identify acquisition information for the network providing recovered or continued service to SIM-1 (i.e., a first network). In block608, the wireless device processor may access a joint acquisition database, and may search the portion of the database associated with SIM-1 (for example, portion402ain the joint acquisition database400shown inFIG. 4A) for the network entry with acquisition information associated with the first network.

In determination block610, the wireless device processor may determine whether a correlation record containing the network entry associated with the first network also provides a network entry associated with a corresponding network for a second SIM (e.g., SIM-2). If the correlation record does not provide a network entry associated with a corresponding network for SIM-2 (i.e., determination block610=“No”), the wireless device processor may attempt to acquire service on SIM-2 using traditional acquisition procedures. For example, in block612the processor may identify a different network entry that represents the network on which SIM-2 last acquired service, such as based on the index order in portion402bof the joint acquisition database400. In block614, the modem stack associated with SIM-2 may begin a recovery scan on frequencies associated with the identified last acquired network (i.e., using the network entry that has the highest priority index number for the second SIM).

If the correlation record provides a network entry associated with a corresponding network for SIM-2 (i.e., determination block610=“Yes”), in block616the modem stack associated with SIM-2 may automatically begin a recovery scan using the acquisition information (e.g., mode, band, channel(s), etc.) provided in the network entry for SIM-2. Once the wireless device has acquired service on the corresponding network for SIM-2, in block618the correlation record linking the first network on SIM-1 and the corresponding network on SIM-2 may be assigned a top index value to reflect its most-recently-used status in the joint acquisition database.

As discussed above, the references to SIM-1 and SIM-2, as well as to a first network, second network, etc., are arbitrary, and may apply to either or any SIM and/or network of the wireless device.

The various embodiments may be implemented in any of a variety of wireless devices, an example of which is illustrated inFIG. 7. For example, the wireless device700may include a processor702coupled to internal memories704and710. Internal memories704and710may be volatile or non-volatile memories, and may also be secure and/or encrypted memories, or unsecure and/or unencrypted memories, or any combination thereof. The processor702may also be coupled to a touch screen display706, such as a resistive-sensing touch screen, capacitive-sensing touch screen infrared sensing touch screen, or the like. Additionally, the display of the wireless device700need not have touch screen capability. Additionally, the wireless device700may have one or more antenna708for sending and receiving electromagnetic radiation that may be connected to a wireless data link and/or cellular telephone transceiver716coupled to the processor702. The wireless device700may also include physical buttons712aand712bfor receiving user inputs. The wireless device700may also include a power button718for turning the wireless device700on and off.

The various embodiments described above may also be implemented within a variety of personal computing devices, such as a laptop computer810as illustrated inFIG. 8. Many laptop computers include a touch pad touch surface817that serves as the computer's pointing device, and thus may receive drag, scroll, and flick gestures similar to those implemented on wireless computing devices equipped with a touch screen display and described above. A laptop computer810will typically include a processor811coupled to volatile memory812and a large capacity nonvolatile memory, such as a disk drive813of Flash memory. The computer810may also include a floppy disc drive814and a compact disc (CD) drive815coupled to the processor811. The computer810may also include a number of connector ports coupled to the processor811for establishing data connections or receiving external memory devices, such as a USB or FireWire® connector sockets, or other network connection circuits for coupling the processor811to a network. In a notebook configuration, the computer housing includes the touchpad817, the keyboard818, and the display819all coupled to the processor811. Other configurations of the computing device may include a computer mouse or trackball coupled to the processor (e.g., via a USB input) as are well known, which may also be use in conjunction with the various embodiments.

The processors702and811may be any programmable microprocessor, microcomputer or multiple processor chip or chips that can be configured by software instructions (applications) to perform a variety of functions, including the functions of the various embodiments described above. In some devices, multiple processors may be provided, such as one processor dedicated to wireless communication functions and one processor dedicated to running other applications. Typically, software applications may be stored in the internal memory704,710,812and813before they are accessed and loaded into the processors702and811. The processors702and811may include internal memory sufficient to store the application software instructions. In many devices the internal memory may be a volatile or nonvolatile memory, such as flash memory, or a mixture of both. For the purposes of this description, a general reference to memory refers to memory accessible by the processors702,811, including internal memory or removable memory plugged into the device and memory within the processor702and811, themselves.

While the terms “first” and “second” are used herein to describe data transmission associated with a SIM and data receiving associated with a different SIM, such identifiers are merely for convenience and are not meant to limit the various embodiments to a particular order, sequence, type of network or carrier.