PATENT DOCUMENT

Publication Number: US-8660501-B2
Application Number: US-201113053105-A
Country: US
Kind Code: B2

Title: Wireless communications circuitry with simultaneous receive capabilities for handheld electronic devices

Abstract:
Handheld electronic devices are provided that contain wireless communications circuitry. The wireless communications circuitry has simultaneous reception functions that allow the handheld devices to simultaneously receive multiple communications signals in a single communications band. The handheld electronic devices may include cellular telephones with music player functionality or other portable devices. The handheld electronic devices may have local wireless communications capabilities for supporting local wireless links such as WiFi and Bluetooth links. Using the simultaneous reception functions of the wireless communications circuitry, users of the handheld electronic devices can simultaneously receive signals such as WiFi and Bluetooth signals.

Claims:
What is claimed is: 
     
       1. Wireless communications circuitry comprising:
 transceiver circuitry comprising a first transceiver circuit and a second transceiver circuit, wherein the first and second transceiver circuits communicate using different communications protocols and a common radio-frequency frequency band; 
 an antenna that handles radio-frequency signals in the common radio-frequency frequency band; 
 a radio-frequency coupler comprising an input and first and second outputs, wherein when the wireless communications circuitry is operated in a first mode, the input receives radio-frequency signals from the antenna and simultaneously provides corresponding first and second reduced-power versions of the received radio-frequency signals to the first and second outputs, respectively, wherein the first reduced-power version of the received radio-frequency signals is received by the first transceiver circuit, and wherein the second reduced-power version of the received radio-frequency signals is received by the second transceiver circuit; 
 a first switch that is connected to the antenna and that has at least first, second, and third positions, wherein the first switch is coupled to at least one of the first and second transceiver circuits when placed in each of the first, second, and third positions; and 
 a second switch that is coupled between the first switch and a transmit-receive port of the second transceiver circuit, wherein when the wireless communications circuitry is operated in a second mode, the first transceiver circuit is active and transmits radio-frequency signals through the first switch and the antenna without passing through the radio-frequency coupler, and wherein when the wireless communications circuitry is operated in a third mode, the second transceiver circuit is active and generates, at the transmit-receive port, radio-frequency signals that are transmitted through the second switch. 
 
     
     
       2. The wireless communications circuitry defined in  claim 1 , wherein:
 when the wireless communications circuitry is operated in the first mode, the first switch is placed in its second position to route radio-frequency signals from the antenna to the input of the radio-frequency coupler and the second switch is placed in its first position so that the radio-frequency coupler is coupled to the second transceiver circuit; 
 when the wireless communications circuitry is operated in the second mode, the first switch is placed in its first position to route radio-frequency signals that have been transmitted from the first transceiver circuit to the antenna; and 
 when the wireless communications circuitry is operated in the third mode, the first switch is placed in its third position and the second switch is placed in its second position so that the antenna is coupled to the transmit-receive port of the second transceiver circuit. 
 
     
     
       3. The wireless communications circuitry defined in  claim 1 , wherein:
 when the wireless communications circuitry is operated in the first mode, the first switch is placed in its second position to route radio-frequency signals from the antenna to the input of the radio-frequency coupler and the second switch is placed in its first position to route signals from the second output of the radio-frequency coupler to the second transceiver circuit; 
 when the wireless communications circuitry is operated in the second mode, the first switch is placed in its first position to route radio-frequency signals that have been transmitted from the first transceiver circuit to the antenna; and 
 when the wireless communications circuitry is operated in the third mode, the first switch is placed in its third position and the second switch is placed in its second position so that the antenna is coupled to the transmit-receive port of the second transceiver circuit through the first and second switches. 
 
     
     
       4. The wireless communications circuitry defined in  claim 1 , wherein:
 when the wireless communications circuitry is operated in the first mode, the first switch is placed in its second position to route radio-frequency signals from the antenna to the input of the radio-frequency coupler and the second switch is placed in its first position to route signals from the second output of the radio-frequency coupler to the second transceiver circuit; 
 when the wireless communications circuitry is operated in the second mode, the first switch is placed in its first position to route radio-frequency signals that have been transmitted from the first transceiver circuit to the antenna; and 
 when the wireless communications circuitry is operated in the third mode, the first switch is placed in its third position and the second switch is placed in its second position so that radio-frequency signals are conveyed between the transmit-receive port of the second transceiver circuit and the antenna through the first and second switches and without passing through the radio-frequency coupler. 
 
     
     
       5. The wireless communications circuitry defined in  claim 1 , wherein:
 when the wireless communications circuitry is operated in the first mode, the first switch is placed in its second position to route radio-frequency signals from the antenna to the input of the radio-frequency coupler and the second switch is placed in its first position to route signals from the second output of the radio-frequency coupler to the second transceiver; 
 when the wireless communications circuitry is operated in the second mode, the first switch is placed in its first position to route radio-frequency signals that have been transmitted from the first transceiver to the antenna through the power amplifier; and 
 when the wireless communications circuitry is operated in the third mode, the first switch is placed in its third position and the second switch is placed in its second position so that the antenna is coupled to the transmit-receive port of the second transceiver circuit through the first and second switches. 
 
     
     
       6. The wireless communications circuitry defined in  claim 1 , further comprising:
 storage and processing circuitry, wherein the storage and processing circuitry is coupled to the transceiver circuitry, and wherein the storage and processing circuitry is configured to generate data for wireless transmission and is configured to process wirelessly received data. 
 
     
     
       7. The wireless communications circuitry defined in  claim 1 , wherein the first transceiver circuit comprises a wireless local area network transceiver circuit. 
     
     
       8. The wireless communications circuitry defined in  claim 1 , wherein the second transceiver circuit comprises a Bluetooth transceiver circuit. 
     
     
       9. The wireless communications circuitry defined in  claim 1 , wherein the first transceiver circuit comprises a wireless local area network transceiver circuit and wherein the second transceiver circuit comprises a Bluetooth transceiver circuit. 
     
     
       10. Wireless communications circuitry comprising:
 a first wireless transceiver circuit that transmits and receives according to a first communications protocol in a given radio-frequency communications frequency band; 
 a second wireless transceiver circuit that transmits and receives according to a second communications protocol in the given radio-frequency communications frequency band, wherein the first and second communications protocols are different; 
 an antenna; 
 a radio-frequency coupler; 
 switching circuitry that is responsive to control signals and that routes radio-frequency signals to and from the antenna, wherein the switching circuitry includes a first switch that has at least first and second positions and that is coupled between the radio-frequency coupler and a transmit-receive port of the second wireless transceiver circuit, wherein the wireless communications circuitry is operative in at least first, second, and third modes of operation, wherein:
 in the first mode of operation, the first wireless transceiver circuit is active and transmits radio-frequency signals through the switching circuitry and the antenna without passing through the radio-frequency coupler; 
 in the second mode of operation, the first and second wireless transceiver circuit are both active and receive respective first and second versions of identical radio-frequency signals through the radio-frequency coupler and the first switch is placed in its first position to route radio-frequency signals from the radio-frequency coupler to the second wireless transceiver circuit; and 
 in the third mode of operation, the first wireless transceiver circuit is inactive and the second wireless transceiver is active and transmits and receives radio-frequency signals through the first switch and the antenna without passing through the radio-frequency coupler and the first switch is placed in its second position so that the antenna is coupled to the transmit-receive port of the second wireless transceiver through the switching circuitry. 
 
 
     
     
       11. The wireless communications circuitry defined in  claim 10  wherein the switching circuitry further comprises a second switch having at least a first position in which the second switch routes the radio-frequency signals transmitted from the first transceiver to the antenna in the first mode of operation and a second position in which the second switch routes the radio-frequency signals from the antenna to the radio-frequency coupler in the second mode of operation. 
     
     
       12. The wireless communications circuitry defined in  claim 10  wherein:
 the switching circuitry further comprises a second switch having at least a first position in which the second switch routes the radio-frequency signals transmitted from the first transceiver to the antenna in the first mode of operation and a second position in which the second switch routes the radio-frequency signals from the antenna to the radio-frequency coupler in the second mode of operation; 
 the radio-frequency coupler has first and second outputs; and 
 during the second mode of operation, the first wireless transceiver circuit receives the first version of the radio-frequency signals from the first output of the radio-frequency coupler and the second wireless transceiver circuit receives the second version of the radio-frequency signals from the second output of the radio-frequency coupler through the first switch. 
 
     
     
       13. The wireless communications circuitry defined in  claim 10  wherein:
 the switching circuitry further comprises a second switch having at least a first position in which the second switch routes the radio-frequency signals transmitted from the first transceiver to the antenna in the first mode of operation and a second position in which the second switch routes the radio-frequency signals from the antenna to the radio-frequency coupler in the second mode of operation; 
 the radio-frequency coupler has first and second outputs; 
 during the second mode of operation, the first wireless transceiver circuit receives the first version of the radio-frequency signals from the first output of the radio-frequency coupler and the second wireless transceiver circuit receives the second version of the radio-frequency signals from the second output of the radio-frequency coupler; 
 the first version and second version of the radio-frequency signals have respective first and second signal powers; and 
 the first signal power is greater than the second signal power. 
 
     
     
       14. The wireless communications circuitry defined in  claim 10  wherein:
 the switching circuitry further comprises a second switch having at least a first position in which the second switch routes the radio-frequency signals transmitted from the first transceiver to the antenna in the first mode of operation and a second position in which the second switch routes the radio-frequency signals from the antenna to the radio-frequency coupler in the second mode of operation; 
 the radio-frequency coupler has first and second outputs; 
 during the second mode of operation, the first wireless transceiver circuit receives the first version of the radio-frequency signals from the first output of the radio-frequency coupler and the second wireless transceiver circuit receives the second version of the radio-frequency signals from the second output of the radio-frequency coupler; 
 the first version and second version of the radio-frequency signals have respective first and second signal powers; and 
 the first signal power is greater than the second signal power by at least 3 dB. 
 
     
     
       15. The wireless communications circuitry defined in  claim 10 , wherein the given radio-frequency communications frequency band comprises a 2.4 GHz radio-frequency communications band. 
     
     
       16. A method for using wireless communications circuitry in a handheld wireless device comprising:
 storing data in storage on the portable wireless device; 
 with processing circuitry that is coupled to the storage, generating data for wireless transmission and processing wirelessly received data; 
 with an antenna and a first transceiver circuit in the wireless communications circuitry, communicating wirelessly in a communications frequency band according to a first communications protocol; 
 with the antenna and a second transceiver circuit in the wireless communications circuitry, communicating wirelessly in the communications frequency band according to a second communications protocol that is different than the first communications protocol; 
 when it is desired to simultaneously receive data with both the first and the second transceivers in a simultaneous receive mode, distributing radio-frequency signals from the antenna simultaneously to the first and second transceivers using a radio-frequency coupler and a switch, wherein the switch is coupled between the radio-frequency coupler and a transmit-receive port of the second transceiver circuit and wherein the switch is placed in a first position during the simultaneous receive mode; and 
 when it is desired to transmit and receive data with the second transceiver circuit while not transmitting or receiving data with the first transceiver circuit, placing the wireless communications circuitry in a given mode of operation in which the first transceiver circuit is inactive and the second transceiver circuit is active and is transmitting and receiving data through the transmit-receive port and the switch and in which the switch is placed in its second position. 
 
     
     
       17. The method defined in  claim 16  further comprising:
 when it is desired to transmit wireless data through the antenna from the first transceiver, placing the wireless communications circuitry in a wireless local area network transmit mode of operation in which the first transceiver is active and transmits radio-frequency signals through the antenna. 
 
     
     
       18. The method defined in  claim 16  further comprising:
 when it is desired to transmit wireless data through the antenna from the first transceiver, placing the wireless communications circuitry in a wireless local area network transmit mode of operation in which the first transceiver is active and transmits radio-frequency signals through the antenna, wherein placing the wireless communications circuitry in the given mode in which the first transceiver circuit is inactive and the second transceiver circuit is active and is transmitting and receiving data and in which the switch is placed in the second position comprises placing the wireless communications circuitry in a Bluetooth transmission mode of operation in which the second transceiver is active and transmitting Bluetooth radio-frequency signals through the antenna. 
 
     
     
       19. The method defined in  claim 16 , wherein the wireless communications circuitry comprises an additional switch coupled between the radio-frequency coupler and the antenna, wherein the additional switch has at least first, second, and third positions, wherein the additional switch is coupled to at least one of the first and second transceiver circuits when it is placed in each of the first, second, and third positions, and wherein placing the wireless communications circuitry in the given mode of operation comprises conveying radio-frequency signals between the antenna and the second transceiver circuit through the switch and the additional switch and without passing through the radio-frequency coupler. 
     
     
       20. The method defined in  claim 16 , wherein the wireless communications circuitry comprises an additional switch coupled between the radio-frequency coupler and the antenna, wherein the additional switch has at least first, second, and third positions, wherein the additional switch is coupled to at least one of the first and second wireless transceiver circuits when it is placed in each of the first, second, and third positions, and wherein distributing the radio-frequency signals from the antenna simultaneously to the first and second transceiver circuits comprises distributing the radio-frequency signals from the antenna simultaneously to the first and second transceiver circuits through the switch, the additional switch, and the radio-frequency coupler.

Description:
This application is a continuation of patent application Ser. No. 11/636,879, filed Dec. 11, 2006, now U.S. Pat. No. 7,933,561 which is hereby incorporated by referenced herein in its entirety. 
    
    
     BACKGROUND 
     This invention relates generally to wireless communications circuitry, and more particularly, to wireless communications circuitry with simultaneous receive capabilities for handheld electronic devices. 
     Handheld electronic devices are becoming increasingly popular. Examples of handheld devices include handheld computers, cellular telephones, media players, and hybrid devices that include the functionality of multiple devices of this type. 
     Due in part to their mobile nature, handheld electronic devices are often provided with wireless communications capabilities. Handheld electronic devices may use long-range wireless communications to communicate with wireless base stations. For example, cellular telephones may communicate using cellular telephone bands at 850 MHz, 900 MHz, 1800 MHz, and 1900 MHz (e.g., the main Global System for Mobile Communications or GSM cellular telephone bands). Handheld electronic devices may also use short-range wireless communications links. For example, handheld electronic devices may communicate using the WiFi® (IEEE 802.11) band at 2.4 GHz and the Bluetooth® band at 2.4 GHz. 
     To satisfy consumer demand for small form factor wireless devices, manufacturers are continually striving to reduce the number of components that are used. For example, in some wireless designs a single antenna is shared by two transceivers. Because there is only a single antenna with this type of approach, device size is minimized. 
     It is not always desirable to share an antenna in a wireless device. In conventional shared antenna arrangements with two transceivers operating on a shared communications frequency, the two transceivers compete with each other for use of the antenna. If, for example, data is being received by one of the transceivers, data cannot be received by the other transceiver. This may lead to dropped data packets and service interruptions. 
     It would therefore be desirable to be able to provide improved wireless communications circuitry for wireless handheld electronic devices. 
     SUMMARY 
     In accordance with an embodiment of the present invention, a handheld electronic device with wireless communications circuitry is provided. The handheld electronic device may have cellular telephone, music player, or handheld computer functionality. The wireless communications circuitry may have multiple transceivers that share an antenna. 
     With one suitable arrangement, the wireless communications circuitry has first and second transceivers. The first transceiver may be, for example, a wireless local area network (WLAN) transceiver integrated circuit that handles IEEE 802.11 traffic. The second transceiver may be a Bluetooth transceiver. The first transceiver and second transceiver may operate in a common frequency band (e.g., a 2.4 GHz communications frequency band). 
     The wireless communications circuitry may have a radio-frequency coupler and switching circuitry. When it is desired to simultaneously receive incoming radio-frequency signals from the antenna with both the first transceiver and the second transceiver, the coupler is used to divide the incoming radio-frequency signals into first and second identical power-reduced versions of the incoming radio-frequency signals. These signals are simultaneously provided to the first and second transceivers in parallel. 
     The first and second versions of the incoming signals that are produced by the coupler may have the same signal power or may have different signal powers. With one suitable arrangement, the coupler is asymmetric, so that the signal that is diverted to the wireless local area network transceiver circuit has a relatively larger power than the signal that is diverted to the Bluetooth transceiver. 
     When it is desired to transmit WLAN data, the switching circuitry is adjusted appropriately and the WLAN transceiver is made active while the Bluetooth transceiver is made inactive. A power amplifier may be used to amplify outgoing transmitted WLAN data. 
     When it is desired to use the Bluetooth transceiver without using the WLAN transceiver, the WLAN transceiver is placed in an inactive state. When the WLAN transceiver is inactive, it is not necessary to receive data simultaneously with both the WLAN and Bluetooth circuits. As a result, the switching circuitry can be adjusted to bypass the coupler. With the coupler bypassed, Bluetooth data can be transmitted or Bluetooth data can be received. When receiving Bluetooth data in this way, there is a relatively larger signal strength, because the insertion loss of the coupler is avoided. If desired, an input amplifier may be placed upstream from the coupler to compensate for the coupler&#39;s insertion loss. 
     Further features of the invention, its nature and various advantages will be more apparent from the accompanying drawings and the following detailed description of the preferred embodiments. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of an illustrative handheld electronic device with wireless communications circuitry in accordance with an embodiment of the present invention. 
         FIG. 2  is a schematic diagram of an illustrative handheld electronic device with wireless communications circuitry in accordance with an embodiment of the present invention. 
         FIG. 3  is a schematic diagram of conventional wireless communications circuitry for a wireless electronic device. 
         FIG. 4  is a schematic diagram of illustrative wireless communications circuitry for a handheld electronic device in accordance with an embodiment of the present invention. 
         FIG. 5  is a schematic diagram of an illustrative coupler that may be used in wireless communications circuitry for a handheld electronic device in accordance with an embodiment of the present invention. 
         FIG. 6  is a table showing illustrative switch settings that may be used with wireless communications circuitry of the type shown in  FIG. 4  in accordance with an embodiment of the present invention. 
         FIG. 7  is a timing diagram that illustrates wireless activity associated with using communications circuitry such as the illustrative wireless communications circuitry of  FIG. 4  in accordance with an embodiment of the present invention. 
         FIG. 8  is an illustrative state diagram showing how wireless communications circuitry in a handheld electronic device such as the wireless communications circuitry of  FIG. 4  may be used to handle wireless data traffic associated with two different transceivers in accordance with an embodiment of the present invention. 
         FIG. 9  is a schematic diagram of illustrative wireless communications circuitry using a 2:1 splitter and low noise amplifier in an input data path in accordance with an embodiment of the present invention. 
         FIG. 10  is a schematic diagram of an illustrative three-way switch that may be used in wireless communications circuitry of the type shown in  FIG. 4  in accordance with an embodiment of the present invention. 
         FIG. 11  is a schematic diagram of an illustrative three-way switch that has been implemented using two two-way switches and that may be used in wireless communications circuitry of the type shown in  FIG. 4  in accordance with an embodiment of the present invention. 
         FIG. 12  is a schematic diagram of an illustrative Bluetooth transceiver and control circuit having an integrated two-way switch that may be used in wireless communications circuitry for a handheld electronic device in accordance with an embodiment of the present invention. 
         FIG. 13  is a schematic diagram of an illustrative wireless local area network (WLAN) and Bluetooth transceiver and control circuit that may be used in wireless communications circuitry for a handheld electronic device in accordance with an embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION 
     The present invention relates generally to wireless communications and more particularly, to wireless communications circuitry that supports antenna sharing in electronic devices such as portable electronic devices. 
     An illustrative portable electronic device in accordance with an embodiment of the present invention is shown in  FIG. 1 . Portable electronic devices such as illustrative portable electronic device  10  may be laptop computers or small portable computers such as those sometimes referred to as ultraportables. Portable electronic devices may also be somewhat smaller devices. Examples of smaller portable electronic devices include wrist-watch devices, pendant devices, headphone and earpiece devices, and other wearable and miniature devices. 
     With one suitable arrangement, the portable electronic devices are handheld electronic devices. Space is at a premium in handheld electronics devices, so antenna-sharing arrangements for handheld electronic devices can be particularly advantageous. The use of handheld devices is therefore generally described herein as an example, although any suitable electronic device may be used with the wireless communications functions of the present invention, if desired. 
     Handheld devices may be, for example, cellular telephones, media players with wireless communications capabilities, handheld computers (also sometimes called personal digital assistants), remote controllers, global positioning system (GPS) devices, and handheld gaming devices. The handheld devices of the invention may also be hybrid devices that combine the functionality of multiple conventional devices. Examples of hybrid handheld devices include a cellular telephone that includes media player functionality, a gaming device that includes a wireless communications capability, a cellular telephone that includes game and email functions, and a handheld device that receives email, supports mobile telephone calls, and supports web browsing. These are merely illustrative examples. Device  10  may be any suitable portable or handheld electronic device. 
     Device  10  includes housing  12  and includes at least one antenna for handling wireless communications. Housing  12 , which is sometimes referred to as a case, may be formed of any suitable materials including, plastic, wood, glass, ceramics, metal, or other suitable materials, or a combination of these materials. In some situations, case  12  may be a dielectric or other low-conductivity material, so that the operation of conductive antenna elements that are located in proximity to case  12  is not disrupted. In other situations, case  12  may be formed from metal elements. In scenarios in which case  12  is formed from metal elements, one or more of the metal elements may be used as part of the antenna(s) in device  10 . 
     Any suitable type of antenna may be used to support wireless communications in device  10 . Examples of suitable antenna types include antennas with resonating elements that are formed from a patch antenna structure, a planar inverted-F antenna structure, a helical antenna structure, etc. To minimize device volume, at least one of the antennas in device  10  may be shared between two transceiver circuits. 
     Handheld electronic device  10  may have input-output devices such as a display screen  16 , buttons such as button  23 , user input control devices  18  such as button  19 , and input-output components such as port  20  and input-output jack  21 . Display screen  16  may be, for example, a liquid crystal display (LCD), an organic light-emitting diode (OLED) display, a plasma display, or multiple displays that use one or more different display technologies. As shown in the example of  FIG. 1 , display screens such as display screen  16  can be mounted on front face  22  of handheld electronic device  10 . If desired, displays such as display  16  can be mounted on the rear face of handheld electronic device  10 , on a side of device  10 , on a flip-up portion of device  10  that is attached to a main body portion of device  10  by a hinge (for example), or using any other suitable mounting arrangement. 
     A user of handheld device  10  may supply input commands using user input interface  18 . User input interface  18  may include buttons (e.g., alphanumeric keys, power on-off, power-on, power-off, and other specialized buttons, etc.), a touch pad, pointing stick, or other cursor control device, a touch screen (e.g., a touch screen implemented as part of screen  16 ), or any other suitable interface for controlling device  10 . Although shown schematically as being formed on the top face  22  of handheld electronic device  10  in the example of  FIG. 1 , user input interface  18  may generally be formed on any suitable portion of handheld electronic device  10 . For example, a button such as button  23  (which may be considered to be part of input interface  18 ) or other user interface control may be formed on the side of handheld electronic device  10 . Buttons and other user interface controls can also be located on the top face, rear face, or other portion of device  10 . If desired, device  10  can be controlled remotely (e.g., using an infrared remote control, a radio-frequency remote control such as a Bluetooth remote control, etc.). 
     Handheld device  10  may have ports such as bus connector  20  and jack  21  that allow device  10  to interface with external components. Typical ports include power jacks to recharge a battery within device  10  or to operate device  10  from a direct current (DC) power supply, data ports to exchange data with external components such as a personal computer or peripheral, audio-visual jacks to drive headphones, a monitor, or other external audio-video equipment, etc. The functions of some or all of these devices and the internal circuitry of handheld electronic device can be controlled using input interface  18 . 
     Components such as display  16  and user input interface  18  may cover most of the available surface area on the front face  22  of device  10  (as shown in the example of  FIG. 1 ) or may occupy only a small portion of the front face  22 . Because electronic components such as display  16  often contain large amounts of metal (e.g., as radio-frequency shielding), the location of these components relative to the antenna elements in device  10  should generally be taken into consideration. Suitably chosen locations for the antenna elements and electronic components of the device will allow the antenna of handheld electronic device  10  to function properly without being disrupted by the electronic components. 
     A schematic diagram of an embodiment of an illustrative handheld electronic device is shown in  FIG. 2 . Handheld device  10  may be a mobile telephone, a mobile telephone with media player capabilities, a handheld computer, a remote control, a game player, a global positioning system (GPS) device, a combination of such devices, or any other suitable portable electronic device. 
     As shown in  FIG. 2 , handheld device  10  may include storage  34 . Storage  34  may include one or more different types of storage such as hard disk drive storage, nonvolatile memory (e.g., flash memory or other electrically-programmable-read-only memory), volatile memory (e.g., battery-based static or dynamic random-access-memory), etc. 
     Processing circuitry  36  may be used to control the operation of device  10 . Processing circuitry  36  may be based on a processor such as a microprocessor and other suitable integrated circuits. With one suitable arrangement, processing circuitry  36  and storage  34  are used to run software on device  10 , such as internet browsing applications, voice-over-internet-protocol (VoIP) telephone call applications, email applications, media playback applications, operating system functions, etc. Processing circuitry  36  and storage  34  may be used in implementing suitable communications protocols. Communications protocols that may be implemented using processing circuitry  36  and storage  34  include internet protocols, wireless local area network protocols (e.g., IEEE 802.11 protocols—sometimes referred to as WiFi®), protocols for other short-range wireless communications links such as the Bluetooth® protocol, etc.) 
     Input-output devices  38  may be used to allow data to be supplied to device  10  and to allow data to be provided from device  10  to external devices. Display screen  16  and user input interface  18  of  FIG. 1  are examples of input-output devices  38 . 
     Input-output devices  38  can include user input-output devices  40  such as buttons, touch screens, joysticks, click wheels, scrolling wheels, touch pads, key pads, keyboards, microphones, cameras, etc. A user can control the operation of device  10  by supplying commands through user input devices  40 . Display and audio devices  42  may include liquid-crystal display (LCD) screens, light-emitting diodes (LEDs), and other components that present visual information and status data. Display and audio devices  42  may also include audio equipment such as speakers and other devices for creating sound. Display and audio devices  42  may contain audio-video interface equipment such as jacks and other connectors for external headphones and monitors. 
     Wireless communications devices  44  may include communications circuitry such as radio-frequency (RF) transceiver circuitry formed from one or more integrated circuits, power amplifier circuitry, passive RF components, one or more antennas, and other circuitry for handling RF wireless signals. Wireless signals can also be sent using light (e.g., using infrared communications). 
     Device  10  can communicate with external devices such as accessories  46  and computing equipment  48 , as shown by paths  50 . Paths  50  may include wired and wireless paths. Accessories  46  may include headphones (e.g., a wireless cellular headset or audio headphones) and audio-video equipment (e.g., wireless speakers, a game controller, or other equipment that receives and plays audio and video content). In one illustrative scenario, paths  50  may include a wireless Bluetooth path that is used to support communications between a Bluetooth headset (one of accessories  46 ) and device  10  and a wireless local area network (WLAN) path (e.g., a WiFi path) that is used to support communications between device  10  and computing equipment  48 . 
     Computing equipment  48  may be any suitable computer. With one suitable arrangement, computing equipment  48  is a computer that has an associated wireless access point (router) or an internal or external wireless card that establishes a wireless connection with device  10 . The computer may be a server (e.g., an internet server), a local area network computer with or without internet access, a user&#39;s own personal computer, a peer device (e.g., another handheld electronic device  10 ), or any other suitable computing equipment. 
     Wireless communications devices  44  may be used to support local and remote wireless links. 
     Examples of local wireless links include WiFi and Bluetooth links and wireless universal serial bus (USB) links. Because wireless WiFi links are typically used to establish data links with local area networks, links such as WiFi links are sometimes referred to as WLAN links. The local wireless links may operate in any suitable frequency band. For example, WLAN links may operate at 2.4 GHz or 5.6 GHz (as examples), whereas Bluetooth links may operate at 2.4 GHz. The frequencies that are used to support these local links in device  10  may depend on the country in which device  10  is being deployed (e.g., to comply with local regulations), the available hardware of the WLAN or other equipment with which device  10  is connecting, and other factors. 
     With one suitable arrangement, which is sometimes described herein as an example, device  10  communicates using both the popular 2.4 GHz WiFi bands (802.11(b) and/or 802.11(g)) and the 2.4 GHz Bluetooth band using the same antenna. In this type of configuration, the antenna is designed to operate at a frequency of 2.4 GHz, so the antenna is suitable for use with the 2.4 GHz radio-frequency signals that are used in connection with both the WiFi and Bluetooth communications protocols. Circuitry  44  may include a coupler and other suitable circuitry that allows WiFi and Bluetooth signals to be simultaneously received. 
     If desired, wireless communications devices  44  may include circuitry for communicating over remote communications links. Typical remote link communications frequency bands include the cellular telephone bands at 850 MHz, 900 MHz, 1800 MHz, and 1900 MHz, the global positioning system (GPS) band at 1575 MHz, and data service bands such as the 3G data communications band at 2170 MHz band (commonly referred to as UMTS or Universal Mobile Telecommunications System). In these illustrative remote communications links, data is transmitted over links  50  that are one or more miles long, whereas in short-range links  50 , a wireless signal is typically used to convey data over tens or hundreds of feet. 
     These are merely illustrative communications bands over which wireless devices  44  may operate. Additional local and remote communications bands are expected to be deployed in the future as new wireless services are made available. Wireless devices  44  may be configured to operate over any suitable band or bands to cover any existing or new services of interest. If desired, multiple antennas and/or a broadband antenna may be provided in wireless devices  44  to allow coverage of more bands. At least one of the antennas (e.g., an antenna used for WiFi and Bluetooth communications at a common communications band frequency of 2.4 GHz) may be shared, as this helps reduce the size of wireless communications circuitry  44  and therefore reduces the size of device  10 . 
     In conventional wireless electronic devices in which an antenna is shared between multiple communications bands, switching circuitry is used to switch between different transceiver modules. While this type of arrangement may be satisfactory in undemanding applications, a shared antenna arrangement that is based solely on switching circuitry can be inadequate in many contemporary situations. 
     Conventional wireless communications circuitry that is based on a traditional shared-antenna architecture is shown in  FIG. 3 . Wireless communications circuitry  52  includes antenna  54 , which handles radio-frequency signals at a frequency of 2.4 GHz. Switch  56  selectively connects antenna  54  to switch port S 1 , S 2 , or S 3 . Ports S 1  and S 2  are connected to wireless local area network (WLAN) integrated circuit  58  by respective paths  66  and  68 . Port S 3  is connected to Bluetooth integrated circuit  60  by path  70 . Wireless local-area-network integrated circuit  58  includes a WiFi transceiver and control circuitry. Bluetooth integrated circuit  60  includes a Bluetooth transceiver and control circuitry. WLAN circuit  58  and Bluetooth circuit  60  communicate with each other using handshaking path  62 . Paths  72  and  74  are used to provide data and control signals to circuits  58  and  60 . 
     WLAN circuit  58  controls the state of switch  56  using control path  64 . When it is desired to transmit WLAN data, switch  56  is connected to position S 1 , so that data can be transmitted from WLAN integrated circuit  58  to antenna  54  over path  66 . Switch  56  is connected to position S 2  when it is desired to receive data with WLAN circuit  58 . In position S 2 , signals from antenna  54  are conveyed through switch  56  and over path  68  to WLAN circuit  58 . Switch  56  has a third position—S 3 —that is used when it is desired to transmit or receive Bluetooth signals. In transmit mode, Bluetooth signals are transmitted to antenna  54  via transmit/receive path  70  and switch  56 . In receive mode, Bluetooth signals that have been received by antenna  54  are conveyed to Bluetooth integrated circuit  60  by switch  56  and path  70 . 
     The conventional arrangement of  FIG. 3  allows antenna  54  to be shared. WiFi traffic is handled by WLAN circuit  58  and Bluetooth traffic is handled by Bluetooth circuit  60 . Switch  56  can be switched between WLAN circuit  58  and Bluetooth circuit  60 , so that circuits  58  and  60  are able to take turns using antenna  54 . Although WLAN circuit  58  and Bluetooth circuit  60  cannot be used at the same time, switch  56  can be switched quickly, so that circuits  58  and  60  are able to use antenna  54  in rapid succession. 
     Because switch  56  cannot be connected to both WLAN circuit  58  and Bluetooth circuit  60  at the same time, it is necessary to prioritize. Consider, as an example, the situation in which a user of communications circuitry  52  is browsing the internet using WLAN circuit  58 , while using Bluetooth connection  60  to control a wireless mouse. In this type of situation, circuits  58  and  60  can decide to favor the Bluetooth connection over the WiFi connection. Whenever it is desired to connect to both the WLAN circuit  58  and the Bluetooth circuit  60  at the same time, the Bluetooth circuit is favored. 
     With this type of prioritization scheme, the user of circuit  52  will be able to use the wireless mouse without noticeable interruption. However, because the Bluetooth connection is favored over the WLAN connection, WLAN data packets will occasionally be dropped. 
     For example, consider the situation in which Bluetooth activity arises while requested internet data is being transmitted to WLAN circuit  58 . To handle the Bluetooth activity, switch  56  will be connected to switch position S 3 . Bluetooth data has priority over WLAN data, so the fact that WLAN circuit  58  is in the midst of receiving internet data is immaterial and switch  56  is switched to position S 3  to ensure that the Bluetooth activity is handled properly. 
     Placing switch  56  in position S 3  allows Bluetooth circuit  60  to transmit and receive Bluetooth data as needed. However, setting switch  56  to position S 3  prevents WLAN circuit  58  from receiving the internet data that is being transmitted. As a result, some internet data packets will be at least temporarily lost. 
     Data interruptions such as these are unavoidable using the conventional wireless communications circuitry arrangement of  FIG. 3 , because it is not possible to set switch  56  to a position that allows simultaneous reception of WLAN and Bluetooth data. Although data interruptions such as these may be acceptable in noncritical applications, in some situations the impact of lost data may be severe. For example, a user might desire to use WLAN circuit  58  to support a voice-over-internet-protocol (VOIP) telephone call over the internet, while using a Bluetooth headset. In real-time audio applications such as these, a high quality connection is critical. Using conventional wireless communications circuit  52  of  FIG. 3  may cause the VoIP voice signal to break up due to lost data packets. 
     Wireless communications circuitry  76  in accordance with an illustrative embodiment of the present invention is shown in  FIG. 4 . As shown in  FIG. 4 , wireless communications circuitry  76  has an antenna  78 . A filter  80  and a direct current (DC) blocking capacitor (not shown) may be used to filter out spurious noise from received signals. Circuitry  76  includes switches  82  and  84  (labeled S 1  and S 2 , respectively). Path  81  connects filter  80  and switch SW 1 . 
     Switch SW 1  may be set to one of three positions, which are labeled A, B, and C in  FIG. 4 . Switch SW 2  may be set to one of two positions, which are labeled D and E in  FIG. 4 . 
     The states of switches SW 1  and SW 2  are controlled by control signals provided on control lines  106  and  104 , respectively. With one suitable arrangement, the control signals are generated by transceiver and control circuitry  108 . 
     Transceiver and control circuitry  108  may contain two or more transceiver circuit such as wireless local-area-network (WLAN) circuit  110  and Bluetooth circuit  120 . For clarity, a two-transceiver-circuit embodiment is described herein. 
     WLAN transceiver circuit  110  may be, for example, an integrated circuit that handles IEEE 802.11(b) or 802.11(g) signals using WiFi transceiver  112  and control circuitry  114 . Bluetooth transceiver circuit  120  may be, for example, an integrated circuit that handles Bluetooth signals using Bluetooth transceiver  116  and control circuitry  118 . Circuits  110  and  120  may be provided as two separate integrated circuits that are mounted on a common circuit board, using a single integrated circuit, or using more than two integrated circuits. With one suitable arrangement, WLAN circuit  110  is an integrated circuit such as Part No. 88W8686 of Marvell Semiconductor, Inc. of Santa Clara, Calif. and Bluetooth circuit  120  is an integrated circuit such as a BlueCore4 device of CSR, Cambridge, England. Circuits  110  and  120  may communicate with each other over handshaking path  126 . 
     Each transceiver circuit handles a different type of wireless data traffic. In the example of  FIG. 4 , WiFi traffic is handled using wireless local-area-network (WLAN) circuit  110  and Bluetooth traffic is handled using Bluetooth circuit  120 . Each of these circuits interfaces with antenna  78  and with circuitry on the handheld electronic device in which wireless communications circuitry  76  is being used. 
     Data and control paths  122  and  124  may be used to form communications paths between transceiver and control circuitry  108  and other circuitry on device  10  such as processing circuitry  36  of  FIG. 2 . Paths  122  and  124  may be used to support any suitable type of data communications. As an example, path  122  may be used to convey control and user data using the so-called secure digital input/output (SDIO) protocol. Paths  124  and  122  may be formed of any suitable number of conductive lines. In the example of  FIG. 4 , path  122  has been formed from a six-line bus and path  124  has been formed from a four-line bus. This is merely illustrative. Paths such as paths  122  and  124  may be formed from single lines or using larger or smaller busses of multiple lines, if desired. 
     WLAN circuit  110  may transmit WLAN data wirelessly using data transmission path  98 . With the illustrative configuration of  FIG. 4 , path  98  can be dedicated to conveying transmitted data for circuit  110 . Transmitted data on path  98  may be amplified by power amplifier  88 . Corresponding amplified versions of the transmitted data signals on path  98  may be provided to switch SW 1  over path  100 . To transmit data over antenna  78 , control signals may be issued on path  106  that direct switch SW 1  to connect path  100  to path  81  (switch position A). When switch SW 1  has been placed in position A and WLAN data is being transmitted over path  98 , wireless communications circuitry  76  of  FIG. 4  may be referred to as operating in WLAN TX mode. In this mode of operation, Bluetooth operations are temporarily blocked, so the position of switch SW 2  is immaterial. 
     Circuitry  76  may have a radio-frequency coupler  86 . An illustrative coupler  86  is shown in  FIG. 5 . As shown in  FIG. 5 , coupler  86  may be implemented as a four-terminal device. Terminal  128  may be used to receive radio-frequency input signals. Termination resistor  136  may be coupled between ground  138  and termination resistor terminal  132 . During operation, input signals that are provided to input terminal  128  are divided into two corresponding output signals on outputs  130  and  134 . As shown by box  144 , coupler  86  typically contains a network of components such as inductors, capacitors, and resistors that cause input signals on path  140  to become coupled onto path  142 . As a result, part of the input signal power to coupler  86  is diverted to output terminal  134 , while part of the input signal power to coupler  86  passes through to output  130 . The splitting ratio of the coupler  86  is typically fixed by the values of the components in network  144 . With one suitable arrangement, the output signal on output terminal  130  is −1.8 dB lower in power than the power of the input signal on input terminal  128  and the power of the coupled output signal on output terminal  134  is −6.5 dB lower than the power of the input signal on terminal  128 . As this example demonstrates, coupler  86  typically exhibits some internal loss. 
     In this example, the coupler produces output signals that differ by about 4.7 dB. One output signal, which represents a first power-reduced version of the received radio-frequency input signals to the coupler, has an output power that is 4.7 dB larger than the other output signal, which represents a second power-reduced version of the received radio-frequency input signals to the coupler. The use of a coupler that produces output signals with −1.8 dB and −6.5 dB outputs is, however, merely illustrative. For example, coupler  86  may produce output signals in which the power for output  130  is equal to the power of output  134  or output signals in which the power for output  130  is greater than the power of output  134 . An advantage of using arrangements in which the output signal power for output  130  is greater than the output signal power for output  134  is that this may divert a relatively small amount of power away from WLAN circuit  110 , thereby helping to preserve proper operation of WLAN circuit  110  under adverse conditions. In general, the power of the signal on output  130  may be any suitable amount greater than the power of the signal on output  134 . For example, the power of the signal on output  130  may be 1 dB greater than the power of the signal on output  134  or more. As another example, the power of the signal on output  130  may be at least 2 dB greater than the power of the signal on output  134 . As a further example, the power of the signal on output  130  may be at least 3 dB greater than the power of the signal on output  134 . 
     As shown in  FIG. 4 , coupler  86  may be used to provide wireless communications circuitry  76  with support for a shared receive mode (shared RX mode). In shared RX mode, control signals may be issued on control path  106  that place switch SW 1  in position B and control signals may be issued on control path  104  that place switch SW 2  in position D. With switches SW 1  and SW 2  configured in this way, data that is received on antenna  78  and that is provided to coupler  86  via shared input path  92  is split into two identical parts, each having a potentially different signal power. A first part of the received data signal is passed to WLAN circuit  110  on shared received data path  96 . A second part of the received data signal is passed to Bluetooth circuit  120  via shared receive data path  94 , switch SW 2 , and path  102 . The data of the signals provided to circuits  110  and  120  in the shared receive mode is the same, but the powers of the signals is dictated by the coupler  86  and may be different. For example, the power of the data signal on path  96  may be −1.8 dB with respect to the incoming data signal on path  92 , whereas the power of the data signal on path  102  may be −6.5 dB with respect to the incoming data signal on path  92  (as an example). 
     During use of wireless communications circuitry  76  of  FIG. 4  in simultaneous receive mode, WLAN circuit  110  and Bluetooth circuit  120  may be in simultaneous operation, each handling respective portions of the incoming data. For example, when incoming data is an internet protocol (IP) packet destined for WLAN circuit  110 , that packet may be received and processed by WLAN circuit  110 . When incoming data is Bluetooth data destined for Bluetooth circuit  120 , Bluetooth circuit  120  may receive and process the incoming data. Circuits  110  and  120  may be presented with both types of data (WLAN and Bluetooth), but can digitally recognize which type of data is being received and can therefore respond only as appropriate. Although signal strengths are reduced somewhat by the presence of coupler  86 , simultaneous data reception is supported, so that demanding applications such as VoIP calls and Bluetooth audio can be simultaneously supported, without concern for lost data packets. 
     When it is desired to transmit Bluetooth data or when it is desired to receive Bluetooth data on a dedicated path without using coupler  86  (i.e., to benefit from a higher Bluetooth input signal power when simultaneous reception of WLAN data is not required), control signals may be issued on control path  106  that place switch SW 1  in position C and control signals may be issued on control path  104  that place switch SW 2  into position E. In this configuration, which is sometimes referred to as Bluetooth TX or dedicated RX mode, path  90  may be used for Bluetooth data transmission or for dedicated Bluetooth data reception. 
     During Bluetooth transmission, transmitted Bluetooth data from Bluetooth circuit  120  is provided to switch SW 2  over path  102 . Switch SW 2 , which is set to position E, conveys the outgoing Bluetooth data to switch SW 1  over path  90 . Switch SW 1 , which is set to position C, conveys the outgoing Bluetooth data to antenna  78  over path  81  and filter  80 . 
     During dedicated RX mode, received Bluetooth data from antenna  78  and filter  80  is received by switch SW 1  over path  81 . Switch SW 1  is set to position C, so switch SW 1  directs the incoming Bluetooth data to switch SW 2  over dedicated RX path  90 . Because coupler  86  is bypassed in this mode, the signal power on path  90  is larger than it would have been had the signal been split by coupler  86 . Because the signal power of the incoming Bluetooth signal is relatively high, it may exhibit a good signal-to-noise ratio. Switch SW 2  is set to position E during dedicated RX mode, so the incoming Bluetooth data is routed to Bluetooth circuit  120  via path  102 . 
       FIG. 6  contains a table that illustrates switch settings involved during the operation of wireless communications circuitry  76  of  FIG. 4 . In table  146 , an entry of “0” indicates that a corresponding switch position is not being used, an entry of “1” indicates that a corresponding switch position is being used, and an entry of “X” indicates a don&#39;t care bit (the position of the switch is immaterial). 
     As shown in table  146 , during WLAN TX mode, switch SW 1  is set to position A, whereas the setting of switch SW 2  is immaterial. In WLAN TX mode, WLAN circuit  110  is active and transmits WLAN data using antenna  78 . 
     During shared RX mode, WLAN circuit  110  and Bluetooth circuit  120  are active simultaneously. Switch SW 1  is set to position B, whereas switch SW 2  is set to position D. In shared RX mode, circuit  110  and circuit  120  receive signals with somewhat reduced powers, but because both circuits are simultaneously active, incoming data is not lost. The type of coupler  86  that is used in the shared RX path influences the signal powers received by WLAN circuit  110  and Bluetooth circuit  120 . In general, any suitable ratio of output powers may be produced by coupler  86 . 
     An advantage to using a coupler arrangement in which relatively more of the outgoing signal power is directed to WLAN circuit  110  than to Bluetooth circuit  120  is that this type of arrangement favors the WLAN circuit over the Bluetooth circuit. WLAN links are often formed over larger distances than Bluetooth links and may therefore require more assistance in maintaining good signal quality. Bluetooth links are often formed with equipment that is in the immediate vicinity of device  10  and may therefore require relatively less assistance in maintaining good signal quality. On balance, it is therefore often preferred to use a coupler  86  that produces an output signal on path  96  that has more power than the corresponding output signal on path  94 . 
     Transceiver circuits such as circuits  110  and  120  in transceiver and control circuitry  108  of  FIG. 4  may be used to support any suitable protocols. The use of circuits that support WiFi and Bluetooth links are being described as an example.  FIG. 7  illustrates how circuits such as circuits  110  and  120  may handle WLAN traffic and Bluetooth audio traffic. In the example of  FIG. 7 , time is plotted on the horizontal axis. According to Bluetooth audio protocol specifications, Bluetooth circuit  120  will be active in Bluetooth time slots  148 - 1  and  148 - 2 . During Bluetooth operations, Bluetooth circuit  120  alternates between transmitting data and receiving data. The Bluetooth time slots are labeled “BT TX” ( 148 - 1 ) and “BT RX” ( 148 - 2 ) to indicate whether Bluetooth circuit  120  is transmitting or receiving Bluetooth data. During time slots  150 , Bluetooth circuit  120  is inactive, as indicated by the labels “BT OFF” in time slots  150 . 
     With conventional wireless communications circuitry of the type shown in  FIG. 3 , WLAN operations are blocked completely during the active Bluetooth time slots. As a result, with conventional circuitry  52  of  FIG. 3 , WLAN data that is sent to circuitry  52  at a time such as time t 2  or at a time such as time t 4  in  FIG. 7  will be lost. Conventional circuitry  52  only allows WLAN data to be successfully transmitted or received at times such as time t 1  or time t 3 , when Bluetooth integrated circuit  60  of  FIG. 3  is inactive. Particularly in environments in which a premium is placed on low-latency and negligible packet loss, such as when supporting VOIP telephone calls, conventional arrangements of the type shown in  FIG. 3  can be disadvantageous. 
     Wireless communications circuitry  76  of the type shown in  FIG. 4  can be used to support a simultaneous RX mode, which allows WLAN circuit  110  and Bluetooth circuit  120  to receive incoming data at the same time. Because both WLAN circuit  110  and Bluetooth circuit  120  can be active and receiving data at the same time, WLAN data can be received at times such as time t 2  in  FIG. 7  as well as times such as times t 1  and t 3 . Unlike conventional circuitry that blocks WLAN data during BT RX time slots, wireless communications circuitry  76  can be used to receive WLAN data during BT RX time slots. As a result, the amount of WLAN data that is blocked due to simultaneous Bluetooth activity is minimized. In applications such as VoIP telephone calls, where it is desirable to minimize data packet loss, the quality of the VoIP service that device  10  can deliver may be improved significantly when using the simultaneous receive functions of wireless communications circuitry  76 . 
     A state diagram illustrating modes in which device  10  and wireless communications circuitry  76  may operate is shown in  FIG. 8 . The embodiment of wireless communications circuitry  76  that is described in connection with the state diagram of  FIG. 8  has a first transceiver that handles wireless local area network (WLAN) communications, also sometimes referred to as WiFi communications or IEEE 802.11 communications and has a second transceiver is used to handle Bluetooth communications. This type of arrangement is merely illustrative. In general, wireless communications circuitry  76  and transceiver and control circuitry  108  can be used to support any suitable communications protocols. The description of WLAN and Bluetooth communications protocols is an example. 
     As shown in  FIG. 8 , wireless communications circuitry  76  and device  10  may operate in at least three states, state  152 , state  154 , and state  156 . 
     In state  152 , Bluetooth circuit  120  is active in Bluetooth TX or dedicated RX mode, whereas WLAN circuit  110  is inactive. State  152  corresponds to the third row in table  146  of  FIG. 6 . In state  152 , switch SW 1  is in position C and switch SW 2  is in position E. When Bluetooth circuit  120  is in transmit mode, a radio-frequency transmitter circuit in transceiver  116  is used to generate outgoing Bluetooth data (e.g., data that has been received via path  124 ). The transmitted Bluetooth data is conveyed to antenna  78  via path  102 , switch SW 2 , path  90 , switch SW 1 , path  81 , filter  80 , and antenna  78 . An example of a time during which Bluetooth data is being transmitted by circuitry  76  is time t 4  in BT TX slot  148 - 1  of  FIG. 7 . When Bluetooth circuit  120  is in dedicated RX mode, Bluetooth that is received from antenna  78  is conveyed to a receiver in transceiver  116  via antenna  78 , filter  80 , path  81 , switch SW 1 , path  90 , switch SW 2 , and path  102 . Bluetooth data may be received over the dedicated RX path  90  in this way at any suitable time (see, e.g., time t 2  in BT RX time slot  148 - 2  of  FIG. 7 ). 
     Circuits such as circuit  108  and processing circuitry  36  may have one or more internal clocks. For example, Bluetooth circuit  120  and WLAN circuit  110  may have each have an internal clock or may access a shared system clock. Using timing information from the clock circuitry and protocols implemented in processing circuitry  36  and circuits  110  and  120 , circuits  110  and  120  and processing circuitry  36  can make decisions on when to switch between different modes of operation in wireless communications circuitry  76 . Consider, as an example, a situation in which WLAN circuit  110  is in a sleep state. At a particular time (or when a particular set of conditions are satisfied), the WLAN circuit  110  wakes up to check for incoming data (as an example). As indicated by line  158 , when the WLAN circuit wakes up to receive WLAN data, wireless communications circuitry  76  transitions from state  152  to state  154 . 
     During transition  158 , WLAN circuit  110  issues control signals for switch SW 1  on path  106  that set switch SW 1  to position B. WLAN circuit  110  also issues control signals on path  104  that set switch SW 2  to position D. Making these adjustments causes signals from antenna  78  to be diverted through coupler  86 . Part of the incoming signal power is directed to WLAN circuit  110  over shared RX path  96  and part of the incoming signal power is directed to Bluetooth circuit  120  over shared RX path  94  and path  102 . Because of the presence of coupler  86 , the incoming signal power is reduced somewhat. However, both circuits  110  and  120  are able to receive the incoming signal at the same time. Because both WLAN circuit  110  and Bluetooth circuit  120  are able to simultaneously receive incoming radio-frequency signals, state  154  is sometimes referred to as shared RX mode. State  154  corresponds to the second row of table  146  in  FIG. 6 . In the diagram of  FIG. 7 , time t 2  in BT RX slot  148 - 2  may be associated with state  154 . 
     When wireless communications circuitry  76  and/or processor  36  determines that WLAN circuit  110  has completed its necessary WLAN receiving activities (i.e., when no data needs to be received or when receive operations are finished), wireless communications circuitry  76  can transition back to state  152 , as indicated by arrow  160 . During transition  160 , WLAN circuit  110  issues control signals for switch SW 1  on path  106  that set switch SW 1  to position C and issues control signals on path  104  that set switch SW 2  to position E. In state  152 , WLAN circuit  110  is inactive and Bluetooth circuit  120  is either transmitting Bluetooth signals or is receiving signals over dedicated RX path  90 . By switching the receive path from shared RX path  94  back to dedicated RX path  90 , coupler  86  is bypassed and Bluetooth circuit  120  is assured of receiving high-quality incoming data. 
     During state  154 , WLAN circuit  110  is active and Bluetooth circuit  120  is active in shared RX mode. In state  154 , when wireless communications circuitry  76  determines that WLAN circuit  110  needs to transmit data, wireless communications circuitry  76  transitions to state  156 , as indicated by transition line  162 . As an example, WLAN circuit  110  may need to transmit an acknowledgement packet. To make this transmission, the WLAN circuit  110  may wait until Bluetooth receive operations have been completed (e.g., when a BT RX slot  148 - 2  has just finished). At this point, Bluetooth circuit  120  becomes inactive. 
     As shown in  FIG. 8 , in state  156 , WLAN circuit  110  is active and is transmitting data. Bluetooth circuit  120  is inactive. During transition  162 , control signals are issued on path  106  that set switch SW 1  to position A. When switch SW 1  is in position A, transmitted WLAN data from WLAN circuit  110  is passed to power amplifier  88  via TX path  98 . Amplifier  88  amplifies the transmitted signal and provides the amplified version of the transmitted signal to switch SW 1  over path  100 . The signal passes through switch SW 1 , is filtered by filter  80 , and is transmitted wirelessly over antenna  78 . 
     The position of switch SW 2  is generally not critical in state  156 , because no signals can be received or transmitted through switch SW 2  so long as switch SW 1  is in position A. Nevertheless, it may be desirable to set switch SW 2  to position E as a default. In this position, switch SW 2  defines a low-loss path for transmitting and receiving data from Bluetooth circuit  120 . By placing switch SW 2  in position E in state  156 , switch SW 2  will be ready to use in the event that wireless communications circuitry  76  transitions back to state  152 . 
     When in state  156 , wireless communications circuitry  76  can transition back to state  154  once WLAN transmission activity is complete, as indicated by line  164 . Wireless communications circuitry  76  makes transition  164  when WLAN circuit  120  is needed to receive data. In state  154 , WLAN circuit  120  may be used to receive data while Bluetooth circuit  120  again becomes active in shared RX mode. During transition  164 , control signals are issued on path  106  that place switch SW 1  in state B and control signals are issued on path  104  that place switch SW 2  in position D. 
     When in state  156 , wireless communications circuitry  76  can also transition to state  152 , as indicated by transition line  166 . Wireless communications circuitry  76  makes transition  166  when Bluetooth operations are required, but WLAN operations are not required. For example, a clock in WLAN circuit  110  may be used to determine that BT OFF slot  150  has expired. When a BT OFF slot expires, Bluetooth operations may be required. If WLAN circuit  110  is not needed for receiving data, wireless communications circuitry  76  can transition to state  152 , as indicated by line  166 . 
     During transition  166 , control signals are issued for switch SW 1  on path  106  that set switch SW 1  to position C. Control signals are issued on path  104  that set switch SW 2  to position E. In state  152 , WLAN circuit  110  is inactive and Bluetooth circuit  120  is either transmitting Bluetooth signals or is receiving signals over dedicated RX path  90 . By switching the receive path from shared RX path  94  back to dedicated RX path  90  during transition  166 , coupler  86  is bypassed and Bluetooth circuit  120  is assured of receiving high-quality incoming data. 
     While in state  152 , it may become necessary to use WLAN circuit  110  to transmit data. For example, processing circuitry  36  may have data that is to be transferred over a wireless local area network with which device  10  is in communication. To transmit the data using WLAN circuit  110 , wireless communications circuitry  166  transitions to state  156 , as indicated by line  168 . During transition  168 , control signals are issued that place switch SW 1  in position A. This connects WLAN transmit path  100  to antenna  78  and allows WLAN circuit  110  to transmit the desired data. The state of switch SW 2  in state  156  is immaterial to the operation of WLAN circuit  110 , but, if desired, may be left in position E to facilitate a transition back to state  152  after the WLAN data has been transmitted. 
       FIG. 9  shows an embodiment of wireless communications circuitry  76  in which coupler  86  has been implemented using a coupler that has an even splitting ratio. With this type of arrangement, incoming signals on path  92  are divided into two parts for respective paths  94  and  96 . Because the power of the divided input signals on paths  94  and  96  is equal, couplers of this type are sometimes referred to as 2:1 splitters. Although shown as a 2:1 splitter in  FIG. 9 , coupler  86  may produce any suitable ratio of output powers on its outputs, if desired. 
     In the embodiment of  FIG. 9 , wireless communications circuitry  76  has an input amplifier interposed in path  92 . Input amplifier  170  may, for example, be a radio-frequency amplifier of the type that is sometimes referred to as a low noise amplifier (LNA). The gain of input amplifier  170  helps to offset the power loss that arises from the use of coupler  86 . With one suitable arrangement, the gain of input amplifier  170  may be set to compensate almost exactly for the loss of coupler  86 . With this type of arrangement, if the loss imposed by coupler  86  is −4 dB to −4.5 dB on each output path (as an example), the gain of input amplifier  170  may be set to +8-9 dB, so that amplifier  170  overcomes the insertion loss of coupler  86 . This is merely an illustrative configuration for amplifier  170  and coupler  86 . In general, coupler  86  may exhibit any suitable associated insertion loss and amplifier  170  may have any suitable gain level to mitigate the loss imposed by coupler  86 . If desired, one or more input amplifiers such as amplifier  170  may be used in wireless communications circuitry  76  and such amplifiers may be placed in other suitable input paths (e.g., path  96 ). 
     Switches such as three-way switch SW 1  and two-way switch SW 2  may be implemented using any suitable switching hardware. With one suitable arrangement, switch SW 1  may be implemented using a single pole three throw (SP3T) switch that is controlled by control signals provided on a two-line control bus as shown in  FIG. 10 . If desired, three-way switch SW 1  may be implemented using two two-way switches  172  and  174 , as shown in  FIG. 11 . 
       FIG. 12  shows how switches may be incorporated into transceiver and control circuitry  108 . In the example of  FIG. 12 , Bluetooth circuit  120  includes switching functionality in the form of two-way switch  84 . Transceiver  116  and control circuitry  118  may be used to send and receive data. Signals may be conveyed between switch  84  and transceiver  116  over path  102 . 
     Circuits such as WLAN circuit  110  and Bluetooth circuit  120  may be provided using one or more integrated circuits. With one suitable arrangement, WLAN circuit  110  is provided using one or more integrated circuits and Bluetooth circuit  120  is provided using one or more integrated circuits. With another suitable arrangement, which is illustrated in  FIG. 13 , the functions of WLAN circuit  110  and Bluetooth circuit  120  are integrated into a common integrated circuit (WLAN/Bluetooth transceiver and control circuit  108 ). When two transceivers are integrated in this fashion, a single control block may be used for processing and control. In the example of  FIG. 13 , WLAN/Bluetooth integrated circuit  108  includes WLAN transceiver  112  and Bluetooth transceiver  116 , which are controlled by a common control block  114 / 118 . This type of arrangement may be used with a separate two-way switch, such as switch SW 2  of  FIG. 4 , or may be used with integrated two-way switch such as switch  84  of  FIG. 13 . If desired, the functionality of other components such as switch  82 , coupler  86 , and amplifiers  88  and  170  may be integrated with circuitry of the type shown in  FIG. 13  in the form of one or more integrated circuits. 
     The foregoing is merely illustrative of the principles of this invention and various modifications can be made by those skilled in the art without departing from the scope and spirit of the invention.

Metadata:
Filing Date: 20110321
Publication Date: 20140225
Grant Date: 20140225
Priority Date: 20061211
Inventors: SANGUINETTI LOUIE J.
Assignee: APPLE INC
CPC Classifications: [{"code": "H04B1/0053", "inventive": true, "first": true, "tree": "[]"}, {"code": "H04B1/406", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04B1/0053", "inventive": true, "first": true, "tree": "[]"}, {"code": "H04B1/406", "inventive": true, "first": false, "tree": "[]"}]
Family ID: 39105904