MOBILE COMMUNICATION DEVICE AND METHOD FOR CARRYING OUT CONFERENCE CALLS

The present invention is generally directed to a communication device, and more specifically to a mobile communication device that enables a plurality of users to concurrently make and receive calls and originate and relay conference calls to one or more third parties.

Mobile communication devices have undergone dramatic development over the past few years. They have become smaller in size, they offer a variety of different functionality, and the devices and networks have typically become more reliable and affordable. As the reliability and affordability of mobile devices and networks have increased, an increasing number of users are foregoing traditional landlines and using one or more mobile devices as their primary source of communication. One drawback that remains, however, is that it is typically inconvenient to set up conference calls involving multiple participants. For example, conferencing with multiple participants typically involves dialing a separate conference call number and entering a passcode that must be exchanged in advance among the participants.

In one exemplary embodiment, a communication device includes a handset having a plurality of transceiver modules and a mixing module coupled to the transceiver modules. Each transceiver module incorporates a separate identity module for identifying the device on the network. Through a single device, one user may make calls in the analog domain, for example, using the microphone and speaker on the mobile handset, and another user may concurrently or separately in time make calls in the digital domain, for example, through a digital headset coupled to the device via a local digital transceiver. In another exemplary embodiment, the communication device includes a mixing module for mixing the signals transmitted and received to and from the first and second transceiver modules. This allows the users of the device to communicate with one another and to add or relay third party conference call participants by making and receiving successive calls and mixing or multiplexing the signals between the transceiver modules. Using a plurality of devices, a conference

call may be held with multiple third parties using only the handsets without the need for a separate conference call number or passcode.

In one exemplary embodiment according to the present invention, a mobile communication device is provided. The mobile communication device includes a first transceiver module for conducting a first telephone call in a first mobile network, wherein the first transceiver module outputs a first output signal associated with the first telephone call; a second transceiver module for conducting a second telephone call in a second mobile network, wherein the second transceiver module outputs a second output signal associated with the second telephone call; a digital interface coupled to at least one of the first transceiver module or the second transceiver module, wherein the digital interface is adapted for transmitting digital signals to a communication accessory; a microphone and a speaker coupled to at least one of the first transceiver module or the second transceiver module; and a mixing module coupled to the first transceiver module and the second transceiver module for selectively combining the first output signal and the second output signal.

In another exemplary embodiment according to the present invention, a method for carrying out a conference call using a mobile communication device is provided. The mobile communication device includes a first transceiver module, a second transceiver module and a mixing module coupled to the first transceiver module and the second transceiver module. The method includes establishing, via the first transceiver module, a first telephone call in a mobile network, the first transceiver module outputting a first reception signal corresponding to the first telephone call; establishing, via the second transceiver module, a second telephone call in a mobile network, the second transceiver module outputting a second reception signal corresponding to the second telephone call; and combining, via the mixing module, the first reception signal and the second reception signal into a combined reception signal and outputting the combined reception signal to a user.

In another exemplary embodiment according to the present invention, a communication device for a mobile network is provided. The communication device includes: a first transceiver module for conducting a first telephone call in the mobile network, wherein the first transceiver

module is adapted to receive a first input signal and to output a first output signal associated with the first telephone call; a second transceiver module for conducting a second telephone call in the mobile network, wherein the second transceiver module is adapted to receive a second input signal and to output a second output signal associated with the second telephone call; a user interface adapted to receive an audible input signal from a user and to output an audible output signal to the user, wherein the user interface is adapted to generate an electrical input signal using the audible input signal and to generate the audible output signal using an electrical output signal; and a mixing module coupled to the first transceiver module, the second transceiver module and the user interface, and adapted to selectively combine the electrical input signal with the first output signal to generate the second input signal, to selectively combine the electrical input signal with the second output signal to generate the first input signal, and to selectively combine the first output signal and the second output signal to generate the electrical output signal.

FIG. 1 illustrates a mobile communication device according to an exemplary embodiment of the present invention;

FIG. 2 is a schematic drawing of the communication device of FIG. 1, showing two transceiver modules, an analog mixing module, a digital mixing module and a local digital interface module; FIG. 3 is a schematic drawing of an exemplary embodiment of the analog mixing module; FIG. 4 is a schematic drawing of an exemplary embodiment of the digital mixing module; FIG. 5 illustrates an arrangement of multiple users carrying out a conference call using the communication device;

FIG. 6 illustrates exemplary signal flow when carrying out two separate calls with the communication device; and

FIG. 7 is a schematic drawing of a generalized embodiment of the communication device including a high-speed processor for mixing, and multiple digital interface modules and transceiver modules.

In exemplary embodiments according to the present invention, a mobile communication device (e.g., a mobile telephone) allows multi-party (e.g., three or more participants) conferencing and/or multiple (i.e., two or more) separate calls concurrently. The mobile communication device

includes at least two transceiver modules (e.g., GSM modules), each having at least one subscriber identity module (SIM) card, to allow making two separate calls concurrently. By way of example, the mobile communication device enables a user to establish a three-party conference call by calling a second person while already in conversation with a first one. This is achieved by mixing (i.e., multiplexing) in analog or digital domain the audio output of a first transceiver module with an external audio input to provide to a second transceiver module as input, mixing in analog or digital domain the audio output of the second transceiver module with the external audio input to provide to the first transceiver module as input, and mixing in analog or digital domain the audio outputs of the first and second transceiver modules to each other to generate a combined audio output from the communication device.

In other embodiments, the mobile communication device allows two separate users to make two separate calls to different parties. In this case, one user may make the call in the analog domain using the speaker and microphone on the mobile communication device, while another user concurrently makes the call in the digital domain using a local digital interface that communicates with a wireless headset (e.g., a Bluetooth headset).

In still other embodiments, the mobile communication device includes a plurality of transceiver modules (e.g., GSM modules including respective SIM cards) and a plurality of digital wireless interface modules (e.g., Bluetooth modules) coupled to a data bus (e.g., a PCM bus) and sharing the bus. The data bus is controlled by a processor (e.g., high-speed processor) that is used for mixing (e.g., PCM mixing) the input/output signals of the transceiver modules. Hence, the processor operates as a master, and the transceiver modules and the digital wireless interface modules operate as slaves on the data bus.

Referring to FIG. 1, a mobile communication device 10 according to one exemplary embodiment of the present invention includes a handset 12 including a first antenna 14 for transmission and reception of signals within the mobile network, a second antenna 16 for transmission and reception of telephone signals within the same or a different mobile network, a typically analog microphone 18 and speaker 20 for communicating directly through the handset 12, and a local digital interface 22,

such as, for example, a Bluetooth transceiver, for wireless communication via an antenna 24 to a digital accessory 26, such as a Bluetooth enabled headset. The digital accessory 26 may also be referred to herein as a headset or a Bluetooth headset. The mobile device further includes a processor 28 for controlling the operation of the mobile telephone device 10.

The mobile device may be configured as a mobile telephone, a standalone device operating over a mobile network, or any other device with a combination of voice communication capability and any other feature, such as a PDA, MP3 player, portable Internet device, digital camera or any other accessory. In alternate embodiments, the analog microphone and speaker may be incorporated into an earpiece connected to a conventional jack on the handset or any other suitable accessory and the digital transceiver and accessory may be configured to employ other standards such as WIFI, DVB-H (Digital Video Broadcasting - Handheld), NFC (Near Field Communication) or any other suitable standard.

In one embodiment, the communication device includes a first transceiver module 30, a second transceiver module 32 and a mixing module 34, which may also be referred to as a multiplexing module. The first transceiver module 30 is coupled to the first antenna 14 and the second transceiver module 32 is coupled to the second antenna 16.

When the communication device 10 is used concurrently by two different users, a first user initiates, receives and relays calls through the mixing module 34 and the analog microphone 18 and speaker 20 together with the first transceiver module 30 and the first antenna 14. The first user may use features typically available on the handset, such as, for example, the numeric keypad, contact list and lists of dialed, received and missed calls. A second user initiates, receives and relays calls through the digital accessory 26 (e.g., Bluetooth headset) together with the second transceiver module 32. The headset in one embodiment includes a display and dialing capability for accessing and dialing numbers. The display on the headset may allow browsing the address book and selecting a new number to dial. This capability provides a flexibility to operate the mobile communication device from a distance with the headset. One suitable headset with a similar display and dialing capability is the Jabra BT8010 Bluetooth headset with OLED display available from GN US, Inc.

located in Nashua, New Hampshire. The mixing module 34, coupled to the first and second transceiver modules 30, 32 and the local digital interface 22, enables users to initiate or relay conference calls with one another and with one or more third parties. The local digital interface 22 may also be referred to as a wireless digital interface, or as a Bluetooth interface when the Bluetooth standard is used as the wireless communications protocol.

The processor 28 controls and coordinates the operation of the transceiver modules 30, 32, the mixing module 34, and the local digital interface 22. While the processor 28 and the mixing module 34 are illustrated as two different modules in FIG. 1, the processor 28 and the mixing module 34 may be implemented as a single integrated circuit or two or more integrated circuits. As such, the functionalities of the processor 28 and the mixing module 34 may be implemented using a single integrated circuit chip or multiple integrated circuit chips.

In one embodiment, the mobile device is configured to operate on a mobile network using the GSM standard, which typically utilizes a subscriber identity module, also known as a SIM, for uniquely identifying the mobile device on the network. The SIM may or may not be removable by the user. By way of example, the SIM may be implemented as a removable SIM card or as an integral part of the first transceiver module 30 or the second transceiver module 32. In this embodiment, the first transceiver module 30 includes a first SIM (or SIM card) 36, and the second transceiver module 32 includes a second SIM (or SIM card) 38. Although the described embodiment is discussed primarily in terms of the GSM standard, the present invention may be readily configured to operate on mobile networks using any other standard such as, for example UMTS, CDMA or TDMA. In an alternate embodiment, one of the transceiver modules may be configured to operate on one type of network and/or with one network carrier, and the other one of the transceiver modules may be configured to operate on a different type of network and/or with a different network carrier.

In FIG. 1 and other drawings in the application, the transceiver modules, the processor, the mixing module, digital signal interface and/or other logic or circuit components are illustrated as modules or discrete components, however, one or more of these modules and/or the components

may be implemented in hardware, software and/or firmware or any suitable combination thereof, in same or different integrated circuits, chips or packages, as those skilled in the art would appreciate.

Referring to FIG. 2, the mixing module 34 includes an analog mixing module (i.e., analog multiplexing module) 46 and a digital mixing module (i.e., digital multiplexing module) 48. The analog mixing module 46 is coupled to the first and second transceiver modules 30, 32 and the microphone 18 and speaker 20 on the handset 12 for multiplexing and transmitting signals between the microphone and speaker and the first and second transceiver modules 30, 32. The digital mixing module 48 is coupled to the first and second transceiver modules 30, 32 and the local digital interface 22 through a data bus 56 for transmitting signals between the first and second transceiver modules and the local digital interface 22. In one embodiment, the data bus 56 may be configured as a time-division multiplexed pulse code modulation (PCM) bus, however, any other suitable bus may be used as those skilled in the art would appreciate. While not shown in FIG. 1, the handset 12 may also include a port or jack for plugging in a wired headset or earpiece for user interface.

In one embodiment, the first transceiver module 30 is configured to output a first analog reception signal A _OUTI associated with a first telephone call to the analog mixing module 46, and the second transceiver module 32 is configured to output a second analog reception signal Aouτ2 associated with a second telephone call to the analog mixing module 46. The analog mixing module 46 combines (e.g., multiplexes) the signals A _OU TI, A _OU T2 to form a combined analog output signal A _OUT which is audibly output to the user through the speaker 20, for example. The analog mixing module 46 accepts audible input signal A ₁ N from the microphone 18 and splits the signal into signals AiNi and A _IN2 for respective transmission through the first and second transceiver modules 30 and 32.

The first transceiver module 30 is further configured to output a first digital reception signal DouTi associated with a first telephone call to the digital mixing module 48, and the second transceiver module 32 is configured to output a second digital reception signal Douτ2 associated with a second telephone call to the digital mixing module 48. The digital mixing module 48 combines (e.g., multiplexes) the signals DQ _U TI, DQ _U T2 to form a combined digital output signal DQ _U T which is

transmitted to the local digital interface 22 through the data bus 56. The local digital interface 22 wirelessly transfers the combined signal to the Bluetooth-enabled headset 26, which creates an audible signal for the second user.

The digital mixing module also accepts an input signal D _IN from the headset 26 through the local digital interface 22 and the data bus 56 and splits the signal into signals D _INI and D _IN2 for respective transmission through the first and second transceiver modules 30, 32. In another embodiment, the signal A _OUT includes the audible content of D _IN and the signal D _OUT includes the audible content of A ₁ N so the first and second users, one on the handset 12 and another on the Bluetooth enabled headset 26 in another room, for example, can communicate with and listen to one another during conference calls.

Referring to FIG. 3, in one embodiment, the analog mixing module 46 more particularly includes a first multiplexing element 120 coupled to the first transceiver module 30 and the second transceiver module 32. In the analog domain, the audio output signal is generated using both audio outputs from the first and second transceiver modules 30, 32, and provided to the speaker 20. The first and second transceiver modules 30 and 32 include respective SIMs 36 and 38. In one embodiment, as these SIMs are based on GSM standard, they each may be referred to as a GSM module. Alternatively, the first and second transceiver modules themselves may be referred to as GSM modules.

In the analog domain according to one exemplary embodiment, audio output of the first transceiver module 30 is multiplexed with the audio input from the microphone 18, and the multiplexed audio signal is provided to the second transceiver module 32 for transmission. The audio output of the second transceiver module 32 is multiplexed with the audio input from the microphone 18, and the multiplexed audio signal is provided to the first transceiver module 30 for transmission.

In more detail, the first transceiver module 30 and the second transceiver module 32 output a first reception signal A _OUTI and a second reception signal Aouτ2, respectively, to the first multiplexing element 120, which multiplexes the signals and forms a combined signal AQ _UT for

output to the speaker 20 on the handset. A second multiplexing element 122 receives the second reception Aouτ2 and an input signal A ₁ N from the microphone 18 to form a first transmission signal Ai _N i for transmission by the first transceiver module 30. A third multiplexing element 124 receives the first reception signal A _OUTI and the input signal A ₁ N from the microphone 18 and multiplexes the signals to form a second transmission signal A _IN2 for transmission by the second transceiver module 32.

This way, the user of the mobile communication device 10 in one embodiment is able to hold a conference call with two separate parties, one through the first transceiver module 30 and the antenna 14, and the other through the second transceiver module 32 and the antenna 16. Here, the voice input signal from the user through the microphone 18 is split and provided to the first and second transceiver modules 30, 32 after being mixed with the voice input signals from the first transceiver module 30 or the second transceiver module 32, such that each of the two parties conferencing with the user can listen to the user as well as the other one of the two parties. The voice signals from the other two parties are mixed together and provided to the user through the speaker 20.

Referring to FIG. 4, in one embodiment, the digital mixing module 48 more particularly includes a first mixing element 130 connected to the first transceiver module 30 and the second transceiver module 32. In the digital domain, the digital outputs (e.g., PCM outputs) of both the first transceiver module (e.g., first GSM module) 30 and the second transceiver module (e.g., second GSM module) 32 are mixed in the digital mixing module 48 to generate a digital output to send to the digital signal interface 22 over the data bus 56. In one embodiment, the digital mixing module 48 also may be referred to as a high-speed processor for PCM mixing, and the digital outputs are PCM outputs. Further, the local digital interface 22 may be a Bluetooth interface. In the digital domain according to one exemplary embodiment, the digital output (e.g., PCM output) of the first transceiver module 30 is mixed (i.e., multiplexed) with the digital input (e.g., PCM input) from the local digital interface 22 (e.g., Bluetooth interface) and provided to the second transceiver module 32. Further, the digital output (e.g., PCM output) of the second transceiver module 32 is

mixed (i.e., multiplexed) with the digital input (e.g., PCM input) from the local digital interface 22 and provided to the first transceiver module 30.

In more detail, the first transceiver module 30 and the second transceiver module 32 output a first reception signal D _OUTI and a second reception signal Douτ2, respectively, to the first mixing element 130, which mixes the signals and forms a combined signal (e.g., multiplexed signal) D _OUT for output through the data bus 56 to the local digital interface module 22. A second mixing element 132 receives the second reception signal Douτ2 and an input signal D _IN from the local digital interface 22 and mixes the signals to form a second transmission signal D _INI for transmission by the first transceiver module 30. A third mixing element 134 receives the first reception signal D _OUTI and the input signal D _IN from the local digital interface 22 and mixes the signals to form a second transmission signal D _IN2 for transmission by the second transceiver module 32.

This way, the user of the mobile communication device 10 is able to hold a conference call with two separate parties, one through the first transceiver module 30 and the antenna 14, and the other through the second transceiver module 32 and the antenna 16. Here, the voice input signal from the user through the headset 26 and the wireless digital interface 22 is split and provided to the first and second transceiver modules 30, 32 after being mixed with the voice input signals from the first transceiver module 30 or the second transceiver module 32, such that each of the two parties conferencing with the user can listen to the user as well as the other one of the two parties. The voice signals from the other two parties are mixed together and provided to the user through the wireless digital interface 22 and the headset 26.

Referring to FIG. 5, a conference call between three and then five different participants 102, 104, 106, 108 and 110, is shown, each participant employing a mobile communication device according to an exemplary embodiment of the present invention. To establish the conference call, the first participant 102 establishes a first telephone call with the second participant 104 and a second telephone call with the third participant 106 using the two separate transceiver modules of a first mobile telephone device 10. Second and third participants 104 and 106, each using a separate communication device 10 according to FIG. 2, may then each establish a further telephone call to

fourth and fifth participants 108, 110, respectively, thereby adding additional participants to the conference call. Here, since the second and third participants 104, 106 each use only one transceiver module of their respective mobile communication device for the telephone call with the first participant 102, they each have a second transceiver module available to establish the telephone calls with the participants 108, 110, respectively. Further, since the fourth and fifth participants 108, 110 each have a second transceiver module available to place another call, a theoretically unlimited number of users may be added to a conference call in an open loop configuration. As the number of participants in the conference call increases, however, spurious effects such as voice transmission delays may become increasingly significant and should be taken into account, thereby posing a practical limit on the maximum number of participants on a conference call.

In one embodiment, when a new participant desires to join in the conference call, he should know beforehand which numbers are free. In another embodiment, when a new participant dials an already taken number, the new participant may be provided with two or more spare numbers to dial in order to join the conference call. In other embodiments, a mechanism to divert calls between the SIM cards on the same mobile communication device may be implemented such that the new participant does not necessarily have to know which of the two telephone numbers are available prior to joining the conference call. In another embodiment, available numbers for creating a conference call chain may be transmitted via text messages or other data transfer.

When the headset has a display and number selection capability or just the number selection capability, it is possible to make two separate calls from the same handset 12. Since two SIM cards (e.g., GSM modules) as well as two separate user interfaces (speaker/microphone and wireless digital interface) are available on the handset 12, one call can be routed through the analog domain using the microphone/speaker and the other through the digital domain using the wireless digital interface (e.g., Bluetooth interface).

Referring to FIG. 6, two separate users may engage in independent calls, separately in time or concurrently, using the same mobile communication device 10. A first user engages in a first call

through the headset 26 via the first transceiver module 30, and separately or concurrently in time, a second user engages in a second call via the microphone 18 and speaker 20 on the handset 12 through the second transceiver module 32. In this case, signals D _IN and D _OUT are transmitted only between the local digital interface and the first transceiver module 30, and signals A ₁ N and A _OUT are transferred only between the microphone and speaker and the second transceiver module 32. While the microphone 18 and the speaker 20 are illustrated in FIG. 6 as being coupled directly to the second transceiver module 32 for convenience, in exemplary embodiments, the microphone 18 and the speaker 20 are coupled to the second transceiver module 32 (and the first transceiver module 30) through the mixing module 34 (in particular, the analog mixing module 46) as illustrated in FIGs. 1, 2 and 3. In other embodiments, of course, the microphone 18 and/or the speaker 20 may be coupled directly to the second transceiver module 32 (or to the first transceiver module 30).

By way of example, the first user on CALL 1 uses the headset 26 (e.g., Bluetooth headset) to wirelessly communicate with the local digital interface 22 to receive the signal D _IN and transmit the signal D _OUT via the data bus 56. In the transmission side of the digital domain, the signal D _IN is provided through the second mixing element 132 to the first transceiver module 30. Here, the mixing of the signals is disabled such that only the signal D _IN (and not the signal Doσrc) is provided through the mixing element 132 as the signal D _INI to the first transceiver module 30. In addition, only the signal D _OUTI is provided through the mixing element 130 as the signal D _OUT to the local digital interface 22.

Further, the mixing of signals is disabled such that there is no mixing between signals D _IN2 and Douτ2 (which may not necessarily be generated) to and from the second transceiver module 32 and the signals from the first transceiver module 30 or the local digital interface 22. Instead, the second transceiver module 32 operates as a transceiver that allows for a communication between a second user and another party to establish CALL 2. This way, the second user on the second transceiver module 32 can communicate using the microphone 18 and the speaker 20, the second transceiver module 32 and the antenna 16 with another party on another communication device separately from the first user who uses the headset 26 and the first transceiver module 30.

In one exemplary embodiment, the first and second transceiver modules 30, 32 and the local digital interface 22 are operated in different time slots while sharing the same PCM bus as slaves to the processor. The number of slots in a PCM frame limits the number of slave devices that can be connected on the same PCM bus.

Referring to FIG. 7, a mobile telephone device may also include more than two transceiver modules and more than one digital interface module. In particular, in one exemplary embodiment, a mobile telephone device includes n transceiver modules 20Oi ••• 20O _n and m digital interface modules 300i ••• 300 _m . The transceiver modules 20Oi ••• 20O _n are coupled to antennas 21Oi ••• 21O _n , respectively, for communicating with a mobile network. The transceiver modules 20Oi ••• 20O _n are GSM modules in one exemplary embodiment. The digital interface modules 300i ••• 300 _m are coupled to antennas 310i ... 310 _m , respectively, for communicating with respective external communication devices 32Oi ... 320 _m , such as Bluetooth enabled headsets. The n transceiver modules 20Oi ••• 20O _n and the m digital interface modules 300i ••• 300 _m are all interlinked to one another via a digital data bus 400 and coupled to a high speed processor 500 functioning as a mixing module. By way of example, the high-speed processor 500 may include functionalities of both the processor 28 and the mixing module 34 of FIG. 1. The digital data bus is configured as a time- division multiplexed PCM bus, wherein the n transceiver modules 20Oi ••• 20O _n and the m digital interface modules 300i ••• 300 _m are operated in different time slots 0 ... m+n-1 of a PCM data frame. The processor 500 is set up as a master unit, whereas the m digital interface modules 300i ••• 300 _m and the n transceiver modules 20Oi ••• 20O _n function as slaves to the processor 500.

In one embodiment, the number of available slots in a PCM frame of the digital data bus 400 limits the number of slave devices, i.e., the combined number of transceiver modules 20Oi ••• 20O _n and digital interface modules 300i ••• 300 _m , that can be connected to and operated on the same digital data bus 400. However, in a modified embodiment, multiple digital data buses, each configured as a PCM bus, with multiple slaves connected to each may be used. In addition, for each device, a serial port may be used for control via an additional processor (not shown). Multiple devices in another

embodiment may share a common serial port. In other embodiments, the same processor (e.g., the processor 500) may be used to control the devices over the serial port.

Accordingly, aspects of the invention provide a mobile communication device (e.g., mobile telephone device) having at least two transceiver modules and being capable of conducting a conference call with a plurality of different users. Although the invention has been described with respect to specific embodiments, it should be recognized that the invention includes the claims and their insubstantial variations supported by this disclosure, and their equivalents.