Abstract:
Disclosed is a multi-SIM cellular telephone capable of accessing information on multiple SIM cards for multiple cellular service subscriptions while simultaneously accessing full functionality of all other features on the handset. It allows users to insert multiple SIM cards, each with a unique IMSI number associated with a unique cellular service subscription. The user can remove any SIM card and port to other handsets at his/her discretion. Purchasing extra cellular service for such purposes as business use is less expensive than was heretofore possible. Some services are only required on one subscription in order for the service to be used since the microprocessor assesses the features of each subscription and applies the required functionality to that SIM card. The multi-SIM cellular telephone also has a phone number that is associated with the handset; this number allows communication to and from the user of the multi-SIM phone on any installed subscription. The multi-SIM cellular telephone also has features that allow it to parse outgoing communication, encrypt it, and transmit it via multiple cellular service lines. The multi-SIM cellular telephone also has features that allow it to decrypt and recombine previously parsed and encrypted incoming communication.

Description:
REFERENCE TO RELATED APPLICATION 
       [0001]    This application is a continuation in part of application Ser. No. 12/927,023 now under notice of allowance, which is claimed as the priority date for this application. 
     
    
     GOVERNMENT INTERESTS 
       [0002]    This invention was made with Government support under Contract No. DE-AC04-94AL85000 awarded by the Department of Energy. The Government may have certain rights in the invention. 
     
    
     BACKGROUND OF THE INVENTION 
       [0003]    1. Field of the Invention 
         [0004]    The present invention relates to a multi-SIM cellular telephone which allows a single cellular telephone to simultaneously access information stored on multiple Subscriber Identity Module (SIM) cards. The multi-SIM cellular phone thus has the capability of allowing the user access to more than one phone number on a single handset. The multi-SIM cellular phone also has a phone number assigned to the device itself so that communication to and from the phone can occur without knowledge of the specific subscriber phone numbers. 
         [0005]    2. Description of the Prior Art 
         [0006]    Cellular telephones are electronic devices used for full duplex two-way radio communication. Cellular service subscriber information is stored in a SIM embedded on a piece of plastic or other suitable material. Henceforth ‘SIM’ and ‘SIM card’ will be used interchangeably. Typically, one SIM card with a single IMSI is installed in any given mobile handset. This allows a handset user to have only one ‘phone line’ per handset at any given time. 
         [0007]    U.S. Pat. No. 7,613,480 describes an invention that allows multiple service subscriptions to be encoded on a single SIM card. This is an upgrade from previous systems that allow only one subscription to be encoded and allows the user to access multiple service regions via software coding. 
         [0008]    This design is limited in the fact that if the user chooses to port one subscription to another handset, then all subscriptions must be ported to the new handset (via the physical process of moving the SIM card from one handset to another). Also, it allows service providers to refuse service or to charge higher rates if the customer chooses to buy service on the second subscription from a service competitor. This design is not for a new phone or new way of doing business. For example, if one subscription has conference-calling capabilities and the others do not, then the invention described in U.S. Pat. No. 7,613,480 does not allow the user of the handset to automatically switch to the other line. Instead, the user would need to disconnect the call and have all conference attendees connect to the subscription with conference capabilities, thereby disclosing the phone number to all conference attendees. This deficiency decreases the privacy of the user of the handset. There is also no provision in U.S. Pat. No. 7,613,480 for the handset itself to be assigned a phone number and have calls to this number directed to any or all of the valid subscriptions installed on this phone. 
         [0009]    U.S. Pat. No. 7,369,848 describes a means by which a person with a cell phone who is outside his/her home network is able to use a single SIM card in order to operate in either the home region or roaming region. The purpose of this invention is to provide a more seamless transition from home service to roaming service. 
         [0010]    This invention is limited in that it requires cooperation between multiple service providers and it places priority on one subscription at a time. Thus, there is a ‘home’ IMSI and a ‘local’ IMSI. There is also limited portability of the subscriptions among different handsets. Furthermore, there is no provision in U.S. Pat. No. 7,369,848 for the phone that uses this invention to be assigned a number that is attached to the IMEI number of the handset. Therefore, all phone calls must be directed to a particular subscription rather than to the number associated with the phone itself. 
       SUMMARY OF THE INVENTION 
       [0011]    The present invention is a multi-SIM cellular telephone that allows the holder of the cell phone handset to have multiple cellular subscriptions (hereafter also known as channels) assigned to the same handset. In size and appearance, it will be similar to current cell phones, but will utilize a microprocessor that is capable of connecting to multiple SIM cards, each of which is associated with a particular subscription to a cellular service carrier. These subscriptions may or may not be for service with different cellular service carriers. 
         [0012]    It is therefore a primary object of the present invention to provide the user of the handset access to more than one cellular phone line on a single handset. 
         [0013]    It is another object of the present invention to allow the user of the phone an economical means of adding additional cellular subscriptions to a single handset for such purposes as obtaining a business phone without buying a new handset. 
         [0014]    It is a further object of the present invention to provide a device that will significantly enhance the convenience and privacy of consumers who have need of multiple cellular telephone lines. 
         [0015]    It is another object of the present invention to provide the customer with the strongest possible signal from any of the cellular carriers for which the user has a subscription. 
         [0016]    It is another object of the present invention to provide the user of the multi-SIM cellular telephone with a means of communicating in a secure manner. This is accomplished by providing a baseband processor that is not connected to the application processor. In this way, no software-based applications can be downloaded and installed on the multi-SIM cellular telephone. The reason for this is that software-based applications that are attached to both the application processor and the baseband processor can be utilized by adversarial persons to hack into communications; this allows a third party to listen to voice communications and to read other types of communication, such as emails and texts. Separating the baseband processor and the application processor prevents this type of espionage. 
         [0017]    These and other objects of the present invention will become apparent to those skilled in this art upon reading the accompanying description, drawings, and claims set forth herein. It will be apparent to those skilled in this art that many embodiments of the present invention are possible without 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0018]      FIG. 1  is a simplified flow diagram showing the general layout of the preferred embodiment of the invention. The arcs connected to the internal antenna, the keyboard, the microphone, and the analog to digital converter signify a means by which these components physically separate the security baseband processor from the application process if the security mode is enabled. In the figure, the phone is not in security mode; rather, it is in normal cellular phone operating mode. 
           [0019]      FIG. 2  is a simplified block diagram showing how the logic installed via firmware on the microprocessor of the multi-SIM cellular phone would direct communication via one of five installed subscriptions to one of multiple modes of operation 
           [0020]      FIG. 3  is a simplified block diagram showing how the multi-SIM cellular phone would have logic for multiple operating modes if communication is active via SIM card  1 . 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Best Mode of the Invention 
       [0021]    The best mode of the invention is shown in  FIG. 1 .  FIG. 1  is a modified simplified schematic demonstrating the best mode contemplated by the inventor of the multi-SIM cellular phone. 
       How to Make the Invention 
       [0022]      FIG. 1  is a modified simplified schematic demonstrating the best mode contemplated by the inventor of the multi-SIM cellular phone. It shows how the microprocessors in the cell phone each connect to multiple SIM cards, thus allowing all other features of the cell phone to be available without duplicating these features, while also ensuring that the security baseband process is never connected to the application processor. The user of the multi-SIM cellular phone is able to buy temporary cellular service from any service provider who sells such service installed on a SIM card and install this service in any open slot in the multi-SIM holding bay that is part of the phone. This service can be installed and initiated at the service provider&#39;s retail location. The invention has enough Random Access Memory (RAM) and Read Only Memory (ROM) to allow the microprocessor to operate all standard functions of modern cell phones as well as the multiple phone subscriptions that are installed on the handset. 
         [0023]      FIG. 2  presents a simplified block diagram of the initial stages of the firmware associated with communications on a multi-SIM cell phone with five installed SIM cards. If communication is established via any of these subscriptions, then the pre-selected operating mode of the phone is invoked.  FIG. 3  presents a simplified block diagram of some of the possible operating modes. It is important to note that the number of and complexity of the operating modes is only limited by the creativity of the firmware engineers. It should also be noted that this type of logic would be duplicated in an embodiment where both a primary baseband processor and a security baseband processor are present. 
       How to Use the Invention 
       [0024]    As all SIM cards that are inserted are physically connected to the one baseband processor at all times, these processors monitor incoming signals for all SIM cards even if the channel selector is set for one particular channel. The processors allows the user of the handset to enter a description for each channel so that the user knows immediately which number is being dialed for any incoming signal. The user then has the option of accepting the incoming call, which immediately causes the attributes of that particular subscription to be accessed and used in the standard way. 
         [0025]    The multi-SIM cell phone has the capability of monitoring all subscriptions and determining which subscription is best for the particular task at hand. For example, suppose the handset user wishes to access the internet via a 4G network. The multi-SIM cell phone monitors the strength of all installed subscriptions and will connect via the fastest connection unless the user has selected another service provider a priori. 
         [0026]    The processors monitor signal strength for all SIM cards on the handset. In this way, one mode of operation allows the phone to smoothly switch to a stronger signal if the user so chooses. In this mode, the phone monitors signal strength and if signal strength drops below a pre-set level, then a stronger signal is chosen if available and a call is automatically placed to the other participant. If only one participant is using the multi-SIM phone or if both participants are using the multi-SIM phone but this mode is selected by only one participant, then the receiver of the phone call that has been initiated will be required to accept the transfer. However, if both participants are using the multi-SIM phone and this mode is selected on both phones, then the transition will be achieved automatically. 
         [0027]    The processors monitor subscription characteristics for all SIM cards that are connected to it. Therefore, in one operating mode, cost to the user can be minimized. Similar to the operating mode that ensures signal strength is optimized (discussed in paragraph [0020]), cost can be minimized by monitoring the service area and the characteristics for the multiple subscriptions. This cost minimization process is subject to constraints entered by the user. For example, the user can enter minimum signal strength before the signal optimization process is initiated and cost among the different subscriptions will be minimized until signal level drops below that pre-set value. Then, the cost optimization process is initiated on the remaining subscriptions. 
         [0028]    All peripheral services that are standard on any current cellular telephone are available to the multi-SIM cellular phone user. These services—such as texting, internet access, games, etc.—are also controlled via the processors of the multi-SIM cellular phone. If one phone line is busy and the user of the multi-SIM cellular phone receives a call on any of the lines installed on the handset, then the option is given to the user of the phone to either place the current caller on hold, to drop the current caller, to ignore the incoming call, or—if conferencing is available on any of the installed lines—to conference the incoming call into the conversation. 
         [0029]    The only connection among the SIM cards to each other are via their associated microprocessor. Thus, no service provider of one subscription has access to the other subscriptions unless they are provided by the same company. For example, if a customer pays for two lines from the same service provider, then it is obvious that the provider will have information from both subscriptions. However, if a customer pays for a subscription that provides many options—such as texting, conferencing, web service, etc.—from one service provider but chooses to buy only basic service from a second provider, neither provider will be able to access this information via the multi-SIM cellular phone. 
         [0030]    The multi-SIM cellular phone has multiple operating modes that allow the user to choose among multiple optimization schemes of the multi-SIM phone. Some examples of these modes are: a signal-strength optimization mode that ensures the strongest possible signal is available for use if multiple service providers are represented on the installed SIM cards; a cost-minimization mode that ensures the least expensive service provider is being used for communication at any point in time; a single-subscription mode that restricts communication to a single subscription; and an elimination mode that allows the user to choose to eliminate communication via any or all installed subscriptions. 
         [0031]    The microprocessor has firmware installed on it that can coordinate conference calling locally (on the phone itself) instead of requiring that a conference-call feature be part of a subscription paid for by the subscriber. In the case of the user of the multi-SIM handset initiating the conference call, the user would input all numbers that he/she wishes to dial, up to and including the total number of installed subscriptions on the phone. The phone would then dial these numbers, using a separate subscription for each number being dialed. The microprocessor would then coordinate all communications to and from each conference attendee. For incoming calls, each incoming communication would be routed to a different subscription and the multi-SIM cell phone user would have the option of conferencing in each additional caller, up to and including the number of installed subscriptions. 
         [0032]    The multi-SIM cell phone has a phone number that is assigned to the handset (as opposed to the subscriptions). If a person dials this phone number, then all subscriptions that are installed on this phone are queried via their respective networks. If the multi-SIM phone is within range of any of these networks, the communication is established. If the phone is within communication range of more than one network, then one of the installed subscriptions is selected via the operating mode chosen a priori by the user of the handset and communication is established via this subscription. 
       Security Features of the Invention 
       [0033]    It is another object of the present invention to provide the user of the multi-SIM cellular telephone with a means of communicating in a secure manner. This is accomplished by providing a baseband processor that is not connected to the application processor. In this way, no software-based applications can be downloaded and installed on the multi-SIM cellular telephone. The reason for this is that software-based applications that are attached to both the application processor and the baseband processor can be utilized by adversarial persons to hack into communications; this allows a third party to listen to voice communications and to read other types of communication, such as emails and texts. Separating the baseband processor and the application processor prevents this type of espionage. 
         [0034]    The cellular telephone parses outgoing communications into multiple parcels according to a pre-determined algorithm, encrypting and digitally marking each parcel so that the parcels can be reassembled in correct order, said telephone then transmitting said communication parcels to one or more telephones with one or more telephone numbers via one or more of the network services that are installed on said cellular telephone via SIM cards; wherein said cellular telephone receives incoming parsed, encrypted, and digitally marked communication via one or more of the network services that are installed on said cellular telephone, decrypts said communication parcels, and reassembles said communication parcels into the order specified by the digital marking of the communication parcels. 
         [0035]    The cellular telephone has a mobile telecommunications handset; an integrated circuit contained in the handset; a microprocessor contained in the handset that coordinates all activities associated with three or more subscriber identity module (SIM) cards. The microprocessor being identified as the “primary baseband processor”, said primary baseband processor consisting of an arithmetic/logic unit (ALU), an instruction register, an instruction decoder, firmware that instructs the primary baseband processor to coordinate all communications associated with all SIM cards connected to said primary baseband processor, and firmware configured to enable said primary baseband processor to coordinate conference communication among all subscriptions installed on the aforementioned cellular phone without requiring any of said subscriptions to have conferencing service installed individually. A device contained in the handset is configured to hold three or more SIM cards, said device simultaneously connecting all said SIM cards to said primary baseband processor; said telephone choosing among a suite of operation modes for said telephone, said suite consisting; a “signal-strength optimization mode”, whereby the telephone monitors signal strength available to all subscriptions installed on said telephone via SIM cards and ensures that when the signal that is actively being used for communication, said communication being either voice communication or data communication, drops below a pre-defined set-point, then said telephone automatically effects a smooth transition from the subscription that is actively being used for communication to the strongest available signal. A “cost minimization mode” monitors location and all features of all subscriptions installed via SIM cards, including cost, and minimizes cost to the user based on the features being used at that time by automatically switching services used for all communications to the subscription with the lowest marginal cost; a “single-subscription mode” that operates on only a single subscription at a time. The subscription can be selected as a priori by the user, said telephone monitoring all channels but not switching among channels for optimization of cost, signal strength, or any other characteristic of the installed subscriptions; said telephone also accepting the installation of a SIM card with a temporary subscription from a cellular service provider that is not represented on any of the SIMs that are currently installed on said telephone and connecting said SIM card with temporary subscription to said primary baseband processor; said telephone also monitoring all incoming communication activity from all installed subscriptions even when one subscription is actively being used for communication, said telephone then offering the user of said handset options by which he/she many choose to disconnect from current communication and accept incoming communication, to place current communication on hold and accept incoming communication, or to ignore incoming communication; said telephone coordinating wireless communications via multiple wireless service subscriptions including full two-way duplex radio telecommunications, said subscriptions being identified by unique International Mobile Subscriber Identifier (IMSI) numbers, each IMSI number being assigned a unique mobile service telephone number. The cellular telephone contains a second microprocessor, known as an application processor, which coordinates all functions of the cellular telephone other than cellular communications. The cellular telephone can contain a third microprocessor, mainly known as the “security baseband processor”. The security baseband processor is connected to one or more SIM cards which are not connected to either the application processor or the primary baseband processor so that wherein the security baseband processor and all SIM cards to which the security baseband processor can be connected are physically disconnected from the application processor, the primary baseband processor, and all communication channels connected to primary baseband processor, are connected to the application processor. 
         [0036]    The cellular telephone parses outgoing communications into multiple parcels according to a pre-determined algorithm, encrypting and digitally marking each parcel so that the parcels can be reassembled in correct order, said telephone then transmitting said communication parcels to one or more telephones with one or more telephone numbers via one or more of the network services that are installed on said cellular telephone via SIM cards; wherein said cellular telephone receives incoming parsed, encrypted, and digitally marked communication via one or more of the network services that are installed on said cellular telephone, decrypts said communication parcels, and reassembles said communication parcels into the order specified by the digital marking of the communication parcel; said parsing, encryption, digital marking, decryption, reassembly, transmission, and receiving of communication being accomplished by either the primary baseband processor of claim  6  or the security baseband processor of claim  6 , dependent upon whether the communication was affected via networks installed on SIM cards connected to the primary or the security baseband processor. 
         [0037]    Thus it will be appreciated by those skilled in the art that the present invention is not restricted to the particular preferred embodiments described with reference to the drawings, and that variations may be made therein without departing from the scope of the present invention as defined in the appended claims and equivalents thereof.