Systems and methods for multiple network access by mobile computing devices

Systems and methods for multiple network access by mobile computing devices are disclosed. In one embodiment, a data bus is used to couple multiple baseband processor endpoints to multiple network access cards, such that each baseband processor endpoint may communicate over the data bus to any of the network access cards. In an exemplary, non-limiting embodiment, the baseband processor endpoint is a modem and the network access cards are subscriber interface module (SIM) cards or universal integrated circuit cards (UICCs). By allowing each of the baseband processor endpoints to use any of the network access cards, different networks may be used for different purposes by the mobile computing device. Further, the use of a single bus in this manner may allow for greater scalability, while also saving pin count, silicon area, board area, and power consumption within the computing device. Such savings ultimately improve the cost of the device.

BACKGROUND

I. Field of the Disclosure

The technology of the disclosure relates generally to mobile computing devices and subscriber access cards that enable the mobile computing devices to interoperate with subscriber networks.

Mobile computing devices have become increasingly common in everyday life. The ability to use such devices as mobile phones, tablets, laptops, and other small, portable, wireless communication devices to remain in contact with friends, family, colleagues, co-workers, and the like is perceived to have great value to the users of such devices. In most situations, such users contact a service provider such as AT&T®, VERIZON®, SPRINT®, or the like, and agree to a service contract that provides the user access to a subsidized mobile terminal and access to a wireless network maintained by the service provider through the mobile terminal. Other service providers offer pay-as-you-go type contracts or the like.

To control access to the wireless network maintained by the service provider, the service provider may require that the mobile terminal have credentials with which to authenticate the mobile terminal to the wireless network. Such credentials may be stored in a secure format on a subscriber interface module (SIM) card or a universal integrated circuit card (UICC) that is received within the housing of the mobile terminal and accessed by a control system of the mobile terminal as needed to pass the credentials to the wireless network. The UICC is generally a single card on which all SIM applications can be placed, including SIM (the original Global System for Mobile communications (GSM) Subscriber Identity Module), USIM (user SIM), CSIM (CDMA SIM), and RUIM (Removable User Identity Module). Each of these types of SIM is viewed as an application, whereby one or many of them can coexist on a physical UICC. Other systems, such as systems that rely on code division multiple access (CDMA) protocols may use a virtual network access card to store such credentials.

While many users may be content to have a single service provider, there may be instances in which users may require access to multiple service providers. In such an event, the user may need to have multiple SIM cards or UICCs so that the mobile terminal may be authenticated with each service provider. Accordingly, there is a need to provide a mobile terminal that may efficiently interact with a plurality of SIM cards and/or UICCs.

SUMMARY OF THE DISCLOSURE

Embodiments disclosed in the detailed description include systems and methods for multiple network access by mobile computing devices. In exemplary embodiments, a data bus is used to couple multiple baseband processor endpoints to multiple network access cards, such that each baseband processor endpoint may communicate over the data bus to any of the network access cards. In an exemplary, non-limiting embodiment, the baseband processor endpoint may be a modem and the network access cards may be subscriber interface module (SIM) cards or universal integrated circuit cards (UICCs). By allowing each of the baseband processor endpoints to use any of the network access cards, different networks may be used for different purposes by the mobile computing device. Further, the use of a single bus in this manner may allow for greater scalability, while also saving pin count, silicon area, board area, and power consumption within the mobile computing device. Such savings ultimately improve the cost of the device.

In this regard in one embodiment, a computing system is disclosed. The computing system comprises a plurality of baseband processor endpoints. The computing system also comprises a communication interface configured to couple to a data bus and allow serialized communication from each of the plurality of baseband processor endpoints to any one of a plurality of network access cards.

In another embodiment, a computing system is disclosed. The computing system comprises a plurality of network access card interfaces, each configured to receive a physical, removable network access card. The computing system also comprises a plurality of baseband processor endpoints. The computing system further comprises a data bus comprising a data channel and a clock channel. The data bus is coupled to each of the plurality of network access card interfaces and the plurality of baseband processor endpoints, such that any baseband processor endpoint may communicate with a network access card positioned in any of the plurality of network access card interfaces.

In another embodiment, a method of assembling a mobile terminal is disclosed. The method comprises providing a serial data bus. The method also comprises coupling a plurality of network access cards to the serial data bus. The method also comprises coupling a plurality of baseband processor endpoints to the serial data bus such that any of the plurality of baseband processor endpoints may communicate with any of the plurality of network access cards.

In another embodiment, a method of operating a computing system is disclosed. The method comprises allowing each of a plurality of baseband processor endpoints to communicate to each of a plurality of network access cards over a serial data bus.

DETAILED DESCRIPTION

With reference now to the drawing figures, several exemplary embodiments of the present disclosure are described. The word “exemplary” is used herein to mean “serving as an example, instance, or illustration.” Any embodiment described herein as “exemplary” is not necessarily to be construed as preferred or advantageous over other embodiments.

Embodiments disclosed in the detailed description include systems and methods for multiple network access by mobile computing devices. In exemplary embodiments, a data bus is used to couple multiple baseband processor endpoints to multiple network access cards, such that each baseband processor endpoint may communicate over the data bus to any of the network access cards. In an exemplary, non-limiting embodiment, the baseband processor endpoint may be a modem and the network access cards may be subscriber interface module (SIM) cards or universal integrated circuit cards (UICCs). By allowing each of the baseband processor endpoints to use any of the network access cards, different networks may be used for different purposes by the mobile computing device. Further, the use of a single bus in this manner may allow for greater scalability, while also saving pin count, silicon area, board area, and power consumption within the mobile computing device. Such savings ultimately improve the cost of the device.

Before addressing exemplary embodiments of the present disclosure, additional material is provided about the nature of SIM cards. While normally each SIM card operates with one defined wireless provider in some instances, it may be possible to use a SIM card that supports two or more wireless providers, by virtue of roaming or other agreements between providers. Such shared use may be configured into the SIM card. This agreement may sometimes be referred to as “multi-SIM” or “multi SIM technology,” which allows the aggregation of multiple SIM credentials onto one physical card.

As additional background, each SIM is normally provisioned with a unique International Mobile Subscriber Identity, or IMSI, which uniquely identifies the identity amongst all operators throughout the globe. Some SIMs may also be provisioned with multiple profiles or policies, each distinguished with a unique IMSI. One application of this is a Dual IMSI which supports two subscriptions (e.g. two different phone numbers) for business and personal needs.

In this regard,FIG. 1is a simplified diagram of a communication environment10with a mobile terminal12operating within networks14,16. Networks14,16may be wireless (for example, cellular). The network14is formed by a first network provider18that operates one or more base stations20through a communication network22. In an exemplary embodiment, the communication network22may be part of or include parts of the Public Land Mobile Network (PLMN), the Public Switched Telephone Network (PSTN), and/or the Internet. The network16is formed by a second network provider24that operates one or more base stations26through a communication network28. In an exemplary embodiment, the communication network28may be part of, or include parts of the PLMN, the PSTN, and/or the Internet. In a further exemplary embodiment, network providers18,24may be competitors, such as AT&T®, VERIZON®, SPRINT®, or the like. The mobile terminal12, operating according to exemplary embodiments of the present disclosure, may operate within both networks14and16. Because the network providers18,24are competitors, they normally have proprietary measures that preclude unauthorized use of the respective networks14,16. In an exemplary embodiment, the proprietary measure takes the form of a SIM card or UICC that is installed in the mobile terminal12. When the mobile terminal12attempts to access a given network14,16, the mobile terminal12may be asked to provide credentials from the SIM card or UICC before access is provided. While there are exceptions such as emergency calls (e.g., 911 calls), in general, the mobile terminal12must have an appropriate network access card to access a network, such as the networks14,16ofFIG. 1.

Exemplary embodiments of the present disclosure provide systems and methods that simplify the co-existence of multiple network access cards within the mobile terminal12ofFIG. 1, such that the mobile terminal12readily operates with multiple proprietary networks such as the networks14,16. By providing access to multiple proprietary networks, a user may have greater flexibility in use of the mobile terminal12. For example, for regions in which a first network (e.g., network14) has poor coverage, the mobile terminal12may operate in the second network (e.g., network16), and vice versa. Likewise, if the user has reached a cap on a data plan with a first network provider18, the mobile terminal12may be used to access data from the second network provider24. Still other uses for multiple network access are possible.

It is worth noting that conventional mobile terminals operating without the benefit of the present disclosure might have access to multiple networks by using Dual SIM Dual Standby (DSDS) or Dual SIM Dual Access (DSDA) implementations. DSDS and DSDA provide a network access card coupled to a baseband processor for each network (i.e., one network access card is attached to one baseband processor, and the other network access card is attached to the other baseband processor). Embodiments of the present disclosure allow consolidation of the data links between network access cards and the baseband processors. Additionally, embodiments of the present disclosure allows greater flexibility and scalability by allowing multiple baseband processors to communicate with multiple network access cards instead of the one to one arrangement of DSDS and DSDA.

FIG. 2provides more detail regarding some of the components within the mobile terminal12ofFIG. 1. In this regard, the mobile terminal12may include a receiver path30, a transmitter path32, an antenna34, a switch36, a baseband processor (BBP)38, a control system40, a frequency synthesizer (not illustrated), a user interface44, and memory46with software48stored therein.

The receiver path30receives information bearing radio frequency (RF) signals from one or more remote transmitters provided by a base station, such as the base station20inFIG. 1. A low noise amplifier (not shown) amplifies the signals. A filter (not shown) minimizes broadband interference in the received signal, while down conversion and digitization circuitry (not shown) down converts the filtered, received signal to an intermediate or baseband frequency signal, which is then digitized into one or more digital streams. The receiver path30typically uses one or more mixing frequencies generated by the frequency synthesizer. The BBP38processes the digitized received signal to extract the information or data bits conveyed in the signal. As such, the BBP38is typically implemented in one or more digital signal processors (DSPs).

With continued reference toFIG. 2, on the transmit side, the BBP38receives digitized data, which may represent voice, data, or control information, from the control system40, which it encodes for transmission. The encoded data is output to the transmitter path32, where it is used by a modulator (not shown) to modulate a carrier signal at a desired transmit frequency. An RF power amplifier (not shown) amplifies the modulated carrier signal to a level appropriate for transmission, and delivers the amplified and modulated carrier signal to the antenna34through the switch36. Collectively, the receiver path30, the transmitter path32, and the frequency synthesizer may be considered a transceiver50.

With continued reference toFIG. 2, a user may interact with the mobile terminal12via the user interface44, such as through a microphone52, a speaker54, a keypad56, and/or a display58. Note that in some embodiments, the keypad56and the display58may be combined into a touch screen display. Audio information encoded in the received signal is recovered by the BBP38, and converted into an analog signal suitable for driving the speaker54. The keypad56and the display58enable the user to interact with the mobile terminal12. For example, the keypad56and the display58may enable the user to input numbers to be dialed, access address book information, or the like, as well as, monitor call progress information. The memory46may have the software48therein as noted above which may effectuate or facilitate operation of the mobile terminal12.

As noted, exemplary embodiments of the present disclosure allow the mobile terminal12to communicate with more than one network14,16by allowing the mobile terminal12to operate with multiple network access cards. While it is certainly possible to have each network access card operate with a respective transceiver (e.g., the transceiver50) for each network14,16with which the mobile terminal12will operate (e.g., DSDS or DSDA), such duplicative operation consumes area within the mobile terminal12, requires routing of many duplicative conductors, and is generally wasteful of resources within the mobile terminal12.

An exemplary embodiment of the present disclosure helps reduce the duplicative conductors and waste referenced above by consolidating communication to and from the network access cards on a single data bus. The plurality of network access cards allows use of multiple networks, which as explained above, is its own form of desirable flexibility. Likewise, each BBP endpoint may have access to the data bus. By connecting each BBP endpoint and each network access card to a single data bus, each BBP endpoint may communicate with each network access card. This arrangement provides flexibility for the BBP endpoint to choose which network with which to establish a voice/data call based on conditions in the device or on policies established in the device. This arrangement further allows savings in pin counts on circuits within the mobile terminal12, silicon area, board area, power consumption, and cost. Likewise, this arrangement provides the ability to scale to almost any number of network access cards and allows for the use of virtual network access cards if desired. Such virtual network access cards may be used in a code division multiple access (CDMA) system such as CDMA2000, where there is no specific need for a physical network access card, and credentials are established via secure communications between the BBP endpoint and a mobile network operator (MNO). This process may result in the maintenance of “secure keys” within the memory46or memory of the BBP38. Still further, this arrangement allows the interface for the network access card to be hosted within an applications processor, a modem, or both, depending on design criteria. Such improved flexibility is a benefit to designers. Further flexibility is enabled because the BBP or the applications processor may be physically located within the same integrated circuit (IC) or across multiple chips. This flexibility provides advantages for the designer in that product capabilities may be determined much later in the product development cycle to adapt to changing market conditions and requirements.

In this regard,FIG. 3illustrates a first exemplary embodiment of a data bus60that couples multiple network access cards (NAC)62, and particularly NAC interface63, to bus interfaces64(also referred to herein as a communication interface). In an exemplary embodiment, the data bus60is a serial bus. As illustrated, the bus interfaces64may be positioned within a modem66or an application processor68(sometimes referred to as a host). The modems66and the application processor68may further include a BBP (not shown) that operates as a BBP endpoint. Each bus interface64may include a multiplexer/demultiplexer (MUX/DEMUX) (not shown) bus arbitration and may include voltage translation logic as needed or desired. Further, the bus interface64may include a serializer to serialize data before placing the data on the data bus60. Additionally, the bus interface64may include a deserializer to deserialize data from the data bus60. In an exemplary embodiment, the bus interface64may append an address to data placed on the data bus60and may place data on the data bus60according to a time division multiplex (TDM) protocol. The source address of the sending endpoint, and one or more destination addresses, may be placed in a protocol field prior to the payload messages sent on the data bus60. It should be appreciated that the NAC interface63is essentially the same as bus interface64but provides these functions for the NAC62. Typically, data transfer is between one BBP (source address) and one NAC62(destination address) in a point-to-point message, but can involve one BBP to multiple NACs62in a broadcast or multicast message. Similarly, data exchange can occur between two BBPs and two NACs62. It can be appreciated that data exchange can occur between any number of endpoints on the data bus60. In an exemplary embodiment of one data line, only one message from source to destination is enabled onto the data bus60, and when this message transfer is complete, the next message that may have been halted due to bus occupancy will be sent.

The NACs62may be SIM cards or UICCs as needed or desired. Likewise, the NACs62may be virtual such as in a CDMA system as described above. Although “virtual”, such virtual NACs may still be a physical endpoint in the designed silicon capable of communications on the data bus60. In another exemplary embodiment, the NAC62may be a multi-SIM card, such as discussed above. In this context, each NAC62is provided a bus address on the data bus60, and each “sub-SIM” is provided a sub-address for each bus address. In still another exemplary embodiment, the NAC62may be a solder-down, non-receptacle SIM card, such as may be used in specific applications where environmental factors such as vibration, heat, or the like, or other factors such as theft prevention may prevent the use of connectors and removability (e.g., automobiles).

Likewise, while not illustrated, it should be appreciated that the NACs62may be removable cards that may be inserted into a NAC interface that has appropriate conductors to interoperate with the NACs62, and includes a receptacle sized so as to receive the removable NACs62. In an exemplary embodiment, the NACs62may have a proprietary new form factor that includes SIM cards and UICCs. It should be appreciated that each of the modems66and the application processor68may be embodied as distinct and separate integrated circuits or could be separate components within a single integrated circuit. The NAC interface may likewise include a serializer and deserializer to serialize data placed on to the data bus60and deserialize data received from the data bus60. As noted above, the NAC interface may be designed to operate according to a TDM protocol when sending and receiving data from the data bus60. The NAC interface may further be designed to provide power to the NAC62on one or more discrete conductors. Alternately, NAC power can be provided separately from the bus interface. Such “out of band” power may be sourced by a separate power management chip.

FIG. 4illustrates a second exemplary embodiment of a data bus60coupling multiple NACs62to a mobile station modem70. The mobile station modem70may include one or more modems72, as well as an application processor74(sometimes referred to as a host). It should be appreciated that the modems72and the application processor74may each include a BBP and operate as a BBP endpoint. It should be appreciated that the mobile station modem70may be embodied as a single integrated circuit or may be part of a system on a chip (SOC). As noted above, the data bus60may operate according to a TDM protocol and each interface may include serializers and deserializers for data conversion from and to the data bus60. In place of the aforementioned TDM protocol, a frequency division multiplex (FDM) protocol could be used for this embodiment, or for the embodiment ofFIG. 3. In such an FDM protocol, each master is assigned a given frequency channel. Still other protocols may be used to avoid conflict on the data bus60.

The data bus60is better illustrated inFIG. 5as a cross-sectional view of a ribbon cable with two conductors80,82and an optional conductor84. The first conductor80is a data channel. The second conductor82is a clock channel. The optional conductor84is a power channel. While illustrated as a ribbon cable, it should be appreciated that the conductors80,82,84may be wire traces on a printed circuit board or other arrangement without departing from the scope of the present disclosure. As noted above, serializers and a TDM protocol are used to place data on the data bus60by the various endpoints of the data bus60. Deserializers and correct addressing schemes allow the destination endpoints to extract data from the data bus60. While note shown, another conductor may be a ground conductor. While not shown, another conductor may be a second data conductor, and data be viewed as transmitted independently on each data conductor, or the two conductors may be grouped to send two bit symbols for each clock period. Symbol encoders and decoders would be required for bit-to-symbol conversion in the transmitter and symbol-to-bit conversion in the receiver. In an exemplary embodiment, the clock channel on the second conductor82may carry data such as in a CCIe (Camera Control Interface extended) protocol as has been presented to the Mobile Industry Processor Interface (MIPI) Alliance. Further, while contemplated as a digital interface, an analog interface may be used with just power, ground, and analog conductors.

Against this explanation of the structure, the methods of using embodiments of the present disclosure are provided with reference toFIGS. 6 and 7. In this regard,FIG. 6illustrates a process90for assembling a mobile terminal12, and particularly for assembling the data bus60within the mobile terminal12. The process90begins by providing the data bus60(block92). The NAC interfaces are coupled to the data bus60(block94). The NAC(s)62are inserted into corresponding NAC interface receptacles (block96). BBP endpoints are then coupled to the data bus60(block98). A clock signal is provided over the data bus60(block100). A TDM data signal is then provided over the data bus60(block102).

FIG. 7illustrates a process110of operating a computing system within a mobile terminal12. The process110begins by serializing the data at a BBP endpoint (block112). This serialized data is sent to any of the NACs62coupled to the data bus60via the data bus60using an appropriate address (block114). The data is deserialized at the NAC62(block116). The process110reverses the communication process by serializing data at the NAC62(block118) and sending data over the data bus60with an address for a BBP endpoint (block120). The data is then deserialized at the BBP endpoint (block122).

In some situations, a wireless local area network (WLAN) may require credentials that are stored on a SIM card or a UICC. Embodiments of the present disclosure are readily adapted for use in such situations. That is, a NAC62with the WLAN credentials may be coupled to the data bus60. A WLAN modem may be coupled to the data bus60. The WLAN modem may (or may not) include a BBP endpoint, but would be able to retrieve the credentials from the NAC62across the data bus60and provide to the WLAN router as needed. In a related exemplary embodiment, Near Field Communications (NFC) may use a Secure Element (SE), which may be considered a type of modem and UICC.

It should be appreciated that the most area savings is achieved through a single data bus60, a system might instantiate more than one bus, such as might be desired for reasons of routing complexity of the traces on a printed circuit board.

The systems and methods for multiple network access by mobile computing devices according to embodiments disclosed herein, may be provided in or integrated into any processor-based device. While more useful for mobile computing devices or mobile terminals, the disclosure is not so limited. Accordingly, examples, without limitation, of processor-based devices that may incorporate embodiments of the present disclosure include a set top box, an entertainment unit, a navigation device, a communication device, a fixed location data unit, a mobile location data unit, a mobile phone, a cellular phone, a computer, a portable computer, a desktop computer, a personal digital assistant (PDA), a monitor, a computer monitor, a television, a tuner, a radio, a satellite radio, a music player, a digital music player, a portable music player, a digital video player, a video player, a digital video disc (DVD) player, and a portable digital video player.

In this regard,FIG. 8illustrates an example of a processor-based system130that can employ the data bus60with BBP endpoints and NACs62illustrated inFIGS. 3 and 4. In this example, the processor-based system130includes one or more central processing units (CPUs)132, each including one or more processors134. The CPU(s)132may have cache memory136coupled to the processor(s)134for rapid access to temporarily stored data. The CPU(s)132is coupled to a system bus138. Note that the system bus138is not the data bus60described above. As is well known, the CPU(s)132communicates with these other devices by exchanging address, control, and data information over the system bus138. For example, the CPU(s)132can communicate bus transaction requests to a memory system140.

Other devices can be connected to the system bus138. As illustrated inFIG. 8, these devices can include the memory system140, one or more input devices142, one or more output devices144, one or more network interface devices146, and one or more display controllers148, as examples. The input device(s)142can include any type of input device, including but not limited to, input keys, switches, voice processors, etc. The output device(s)144can include any type of output device, including but not limited to, audio, video, other visual indicators, etc. The network interface device(s)146can be any devices configured to allow exchange of data to and from a network150. The network150can be any type of network, including but not limited to, a wired or wireless network, a private or public network, a local area network (LAN), a wide local area network (WLAN), and the Internet. The network interface device(s)146can be configured to support any type of communication protocol desired.

The CPU(s)132may also be configured to access the display controller(s)148over the system bus138to control information sent to one or more displays152. The display controller(s)148sends information to the display(s)152to be displayed via one or more video processors154, which process the information to be displayed into a format suitable for the display(s)152. The display(s)152can include any type of display, including but not limited to a cathode ray tube (CRT), a liquid crystal display (LCD), a plasma display, etc.