PATENT DOCUMENT

Publication Number: US-8577321-B2
Application Number: US-95925810-A
Country: US
Kind Code: B2

Title: Methods for selecting antennas to avoid signal bus interference

Abstract:
Electronic devices may have multiple antennas. A first antenna may be located at one end of a device and a second antenna may be located at another end of the device. An input-output port in a device may have a connector that receives a mating connector associated with external equipment. The input-output port and the second antenna may be located at one of the ends of the electronic device. When equipment such as an external video accessory is in use, input-output circuitry in an electronic device may transmit high speed data signals through the input-output port. The presence of activity on the input-output port such as video data or other data transmissions may be monitored by control circuitry in the electronic device. When input-output port activity is detected, use of the second antenna in receiving radio-frequency signals can be inhibited.

Claims:
What is claimed is: 
     
       1. An electronic device, comprising:
 an input-output data port that is adapted to receive an external connector; 
 at least first and second antennas, wherein the first antenna is located farther from the input-output port than the second antenna; and 
 radio-frequency transceiver and control circuitry that inhibits use of the second antenna in receiving radio-frequency signals by monitoring the rate at which data signals are being transmitted through the input-output data port. 
 
     
     
       2. The electronic device defined in  claim 1  wherein the radio-frequency transceiver and control circuitry is configured to inhibit the use of the second antenna in response to determining that data signals are being transmitted through the input-output data port at a data rate exceeding a predetermined data rate. 
     
     
       3. The electronic device defined in  claim 1  wherein the radio-frequency transceiver and control circuitry is configured to receive signals from the first and second antennas in an antenna diversity mode in response to inactivity on the input-output data port. 
     
     
       4. The electronic device defined in  claim 1  wherein the electronic device comprises a cellular telephone, wherein the first antenna comprises an upper cellular telephone antenna at an upper end of the cellular telephone, and wherein the second antenna comprises a lower cellular telephone antenna at a lower end of the cellular telephone antenna. 
     
     
       5. The electronic device defined in  claim 4  wherein the input-output data port comprises a 30-pin data port. 
     
     
       6. The electronic device defined in  claim 4  wherein the radio-frequency transceiver and control circuitry comprises input-output circuitry that is configured to transmit video signals through contacts in the input-output port and wherein the radio-frequency transceiver and control circuitry is configured to inhibit use of the second antenna in receiving radio-frequency signals whenever the input-output port is transmitting the video signals. 
     
     
       7. A method of operating an electronic device that has at least first and second antennas and an input-output data port having a connector that is adapted to receive a mating external connector, comprising:
 in a first mode of operation, using at least the second antenna to receive radio-frequency signals; 
 in a second mode of operation, using only the first antenna to receive radio-frequency signals; and 
 switching from the first mode of operation to the second mode of operation in response to detection of use of the input-output port to transmit data. 
 
     
     
       8. The method defined in  claim 7  wherein switching from the first mode of operation to the second mode of operation comprises switching from the first mode of operation to the second mode of operation in response to detection of use of the input-output port to transmit video data. 
     
     
       9. The method defined in  claim 7  wherein switching from the first mode of operation to the second mode of operation comprises switching from the first mode of operation to the second mode of operation in response to detection of use of the input-output port to transmit data at a data rate in excess of a predetermined threshold data rate and wherein the predetermined threshold data rate is greater than 1 Gbps. 
     
     
       10. The method defined in  claim 7  further comprising:
 in the first mode of operation, using both the first and second antennas in receiving radio-frequency signals in a diversity antenna mode. 
 
     
     
       11. An electronic device, comprising:
 first and second antennas; 
 an input-output data port having a connector that is configured to receive a mating external connector; and 
 radio-frequency transceiver and control circuitry that is coupled to the first and second antennas, wherein the radio-frequency transceiver and control circuitry includes input-output circuitry that is operable to transmit data signals through the input-output data port, wherein the radio-frequency transceiver and control circuitry monitors the input-output data port for activity, and wherein the radio-frequency transceiver and control circuitry is configured to inhibit use of the second antenna in receiving radio-frequency signals by monitoring an amount of data that is being transmitted through the input-output data port. 
 
     
     
       12. The electronic device defined in  claim 11  wherein the connector of the input-output data port comprises a 30-pin connector. 
     
     
       13. The electronic device defined in  claim 12  wherein the electronic device comprises has opposing ends and wherein the second antenna and the 30-pin connector are located at one of the ends of the electronic device. 
     
     
       14. The electronic device defined in  claim 12  wherein the electronic device comprises a cellular telephone having an upper end in which the first antenna is located and a lower end in which the second antenna and the 30-pin connector are located. 
     
     
       15. The electronic device defined in  claim 11  wherein the electronic device comprises a cellular telephone having an upper end at which the first antenna is located and a lower end at which the second antenna is located. 
     
     
       16. The electronic device defined in  claim 15  wherein the radio-frequency transceiver and control circuitry is configured to receive radio-frequency signals from the first antenna while inhibiting use of the second antenna. 
     
     
       17. The electronic device defined in  claim 16  wherein the radio-frequency transceiver and control circuitry is configured to receive radio-frequency signals from the second antenna in response to detection of a lack of interference-producing data signals flowing through the input-output data port. 
     
     
       18. The electronic device defined in  claim 11  wherein the radio-frequency transceiver and control circuitry is configured to receive radio-frequency signals from the first antenna while inhibiting use of the second antenna. 
     
     
       19. The electronic device defined in  claim 11  wherein the transceiver and control circuitry is configured to receive radio-frequency signals from the second antenna in response to detection of a lack of interference-producing data signals flowing through the input-output data port.

Description:
BACKGROUND 
     This relates to electronic devices with wireless circuitry, and more particularly, to techniques for using antennas in an electronic device so as to avoid potential interference. 
     Electronic devices such as cellular telephones include wireless circuitry. Input-output ports may be used to connect electronic devices with wireless circuitry to accessories. For example, many devices include ports to which a user may connect an audio-video accessory such as a display. 
     When a device communicates with an external accessory such as a display, high-speed data signals are transmitted and received by the device. As these high-speed signals pass through the input-output port of the device, circuitry that is adjacent to the input-output port may be affected. In particular, if an antenna is located within the vicinity of the input-output port, the antenna may pick up electromagnetic interference from the input-output port. 
     The electromagnetic interference may be sufficiently strong to disrupt normal device operation. For example, a cellular telephone receiver that is coupled to the antenna may be so overwhelmed with interference that the cellular telephone receiver will be unable to detect incoming cellular telephone calls or may drop an existing call. 
     It would therefore be desirable to be able to provide improved ways in which to avoid the effects of electromagnetic interference in a wireless electronic device that communicates using input-output ports. 
     SUMMARY 
     Wireless electronic devices such as cellular telephones, computers, and other electronic equipment may have multiple antennas. One antenna may be located at one end of a device and another antenna may be located at another end of the device. An input-output port in a device may have a connector that receives a mating connector associated with external equipment. The input-output port may be used to convey high speed data signals for the external equipment. The high speed signals may, for example, include video signals for displaying video images on the external equipment. 
     An electronic device may have control circuitry that monitors activity on the input-output port. The control circuitry can determine when the input-output port is in use, when the input-output port is being used to transmit data at high data rates, when the input-output port is being used to transmit video signals or other bandwidth-intensive data, or when the input-output port is otherwise being used to handle more than a predetermined amount of activity. 
     Activity on the input-output port may generate electromagnetic interference for a given one of the antennas, due to the proximity of that antenna and the input-output port. To ensure that the electronic device can receive signals properly during use of the input-output port, the control circuitry may inhibit use of the given antenna to receive incoming radio-frequency signals whenever activity on the input-output port is detected. When the control circuitry determines that the input-output port is handling less than the predetermined amount of activity, the given antenna can be used for receiving signals. For example, the control circuitry can use both of the antennas in a receive antenna diversity mode whenever inactivity on the input-output port is detected. 
     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 electronic device in which circuitry may be configured to ensure that electromagnetic interference does not disrupt device operation when an input-output port in the device is active in accordance with an embodiment of the present invention. 
         FIG. 2  is a circuit diagram of an electronic device in accordance with an embodiment of the present invention. 
         FIG. 3  is diagram of illustrative steps involved in operating a device of the types shown in  FIGS. 1 and 2  in accordance with an embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION 
     An illustrative electronic device that may be operated so as to avoid interference from activity on input-output ports is shown in  FIG. 1 . Electronic devices such as illustrative electronic device  10  of  FIG. 1  may be laptop computers, tablet computers, cellular telephones, media players, other handheld and portable electronic devices, smaller devices such as wrist-watch devices, pendant devices, headphone and earpiece devices, other wearable and miniature devices, or other electronic equipment. 
     As shown in  FIG. 1 , device  10  includes housing  12 . Housing  12 , which is sometimes referred to as a case, may be formed of materials such as plastic, glass, ceramics, carbon-fiber composites and other composites, metal, other materials, or a combination of these materials. Device  10  may be formed using a unibody construction in which most or all of housing  12  is formed from a single structural element (e.g., a piece of machined metal or a piece of molded plastic) or may be formed from multiple housing structures (e.g., outer housing structures that have been mounted to internal frame elements or other internal housing structures). 
     Device  10  may, if desired, have a display such as display  14 . Display  14  may, for example, be a touch screen that incorporates capacitive touch electrodes. Display  14  may include image pixels formed from light-emitting diodes (LEDs), organic LEDs (OLEDs), plasma cells, electronic ink elements, liquid crystal display (LCD) components, or other suitable image pixel structures. A cover glass member may cover the surface of display  14 . Buttons such as button  16  may pass through openings in the cover glass. Openings may also be formed in the cover glass of display  14  to form a speaker port such as speaker port  18 . 
     Openings in housing  12  may be used to form input-output ports, microphone ports, speaker ports, button openings, etc. For example, opening  20  may be used to form an input-output port that receives a connector on a cable. The connector may be, for example, a 30-pin data connector or other suitable data connector. 
     Wireless communications circuitry in device  10  may be used to form remote and local wireless links. The wireless communications circuitry may include one or more antennas. Single band and multiband antennas may be used. For example, a single band antenna may be used to handle local area network communications at 2.4 GHz (as an example) or a multiband antenna may be used to handle local area network communications at 2.4 GHz and at 5 GHz. As another example, a multiband antenna may be used to handle cellular telephone communications in multiple cellular telephone bands. Antennas may also be used to receive global positioning system (GPS) signals at 1575 MHz in addition to cellular telephone signals and/or local area network signals. Other types of communications links may also be supported using single-band and multiband antennas. 
     Antennas may be located at any suitable locations in device  10 . For example, one antenna may be located in an upper region such as region  22  at the upper end of an elongated device housing and another antenna may be located in a lower region such as region  24  at the lower end of an elongated device housing. If desired, antennas may be located along device edges, in the center of a rear planar housing portion, in device corners, etc. 
     Antennas in device  10  may be used to support any communications bands of interest. For example, device  10  may include antenna structures for supporting local area network communications (e.g., IEEE 802.11 communications at 2.4 GHz and 5 GHz for wireless local area networks), signals at 2.4 GHz such as Bluetooth® signals, voice and data cellular telephone communications (e.g., cellular signals in bands at frequencies such as 850 MHz, 900 MHz, 1800 MHz, 1900 MHz, 2100 MHz, etc.), global positioning system (GPS) communications at 1575 MHz or other satellite navigation system communications, signals at 60 GHz (e.g., for short-range links), etc. 
     A schematic diagram showing illustrative components that may be used in device  10  of  FIG. 1  is shown in  FIG. 2 . As shown in  FIG. 2 , device  10  may include control circuitry  28 . Control circuitry  28  may include storage such as hard disk drive storage, nonvolatile memory (e.g., flash memory or other electrically-programmable-read-only memory configured to form a solid state drive), volatile memory (e.g., static or dynamic random-access-memory), etc. Processing circuitry in control circuitry  28  may be used to control the operation of device  10 . This processing circuitry may be based on one or more microprocessors, microcontrollers, digital signal processors, baseband processors, application specific integrated circuits, etc. 
     Control circuitry  28  may be 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. To support interactions with external equipment, control circuitry  28  may be used in implementing communications protocols. Communications protocols that may be implemented using control circuitry  28  include internet protocols, Universal Serial Bus (USB) protocols and other serial link protocols, protocols for conveying data over parallel buses, protocols for conveying analog data signals, 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, cellular telephone protocols, MIMO protocols, antenna diversity protocols, etc. 
     Control circuitry  28  may include input-output circuitry  30 . Input-output circuitry  30  may be coupled to input-output port connector  34 . Input-output circuitry  30  may include digital communications circuitry for supporting communications over one or more serial links (e.g., a single serial link or multiple parallel lanes in a multi-lane communications path), digital communications circuitry for supporting communications over a parallel bus, analog communications circuitry, video circuitry (e.g., a video display driver circuit for driving video signals onto a display such as an external computer monitor or television), and other suitable input-output circuitry. 
     Connector  34  may mate with a corresponding connector that is associated with external equipment. For example, connector  34  may mate with a connector such as connector  40  that is part of external equipment such as accessory or that is connected to external equipment via cable  42 . Cable  42  may be pigtailed to accessory  44  or may have a connectors at both ends (e.g., one connector such as connector  40  may be used in connecting cable  42  to device  10  and another connector may be used in connecting cable  42  to accessory  44 ). Connectors such as connectors  34  and  40  may have mating contacts such as input-output pins  36  on connector  34  and input-output pins  38  on connector  40 . Connectors  34  and  40  may be 30-pin data connectors, Universal Serial Bus (USB) connectors, audio jack connectors, IEEE 1394 connectors, external serial advanced technology (eSATA) connectors, High Definition Multimedia Interface (HDMI) connectors, DisplayPort connectors, or other data connectors. 
     Accessory  44  may be a computer display, a television display, a display associated with other equipment, a storage device, an input-output device, audio-video equipment such as a stereo system, a wireless device (e.g., an external wireless local area network adapter), a communications device (e.g., an Ethernet adapter), or other electronic equipment. Accessory  44  may include one or more integrated circuits or other circuitry for interfacing with input-output circuitry  30 . For example, accessory  44  may include video display circuitry that receives video signals from input-output circuitry  30  and that displays corresponding video content on a display within accessory  44  or associated with accessory  44 . In configurations in which accessory  44  is a communications device or storage device, accessory  44  may include circuitry for receiving data from input-output circuitry that is to be communicated or stored by accessory  44 . If desired, accessory  44  may be an adapter that serves an interface between device  10  and external equipment. For example, accessory  44  may be a video adapter that receives image data from device  10  and that drives corresponding video signals into an attached external display (as an example). Accessory  44  may, in general, be any electrical equipment. 
     Control circuitry  28  may be coupled to transceiver circuitry  46  and other components  58 . Components  58  may include touch screens, displays without touch sensor capabilities, buttons, joysticks, click wheels, scrolling wheels, touch pads, key pads, keyboards, microphones, cameras, buttons, speakers, status indicators, light sources, audio jacks and other audio port components, digital data port devices, light sensors, motion sensors (accelerometers), capacitance sensors, proximity sensors, etc. 
     Transceiver circuitry  46  may include one or more transmitters  48  and one or more receivers  50 . Device  10  may use radio-frequency transceiver circuitry  46  in handling communications in radio-frequency communications bands such as cellular telephone communications bands, wireless local area network bands, satellite navigation system bands, and other wireless communications bands. The transmitters and receivers of transceiver circuitry  46  may handle the 2.4 GHz and 5 GHz bands for WiFi® (IEEE 802.11) communications bands and the 2.4 GHz Bluetooth® communications band. Circuitry  46  may use cellular telephone transceiver circuitry for handling wireless communications in cellular telephone bands such as the bands at 850 MHz, 900 MHz, 1800 MHz, 1900 MHz, and 2100 MHz (as examples). Circuitry  46  may include a Global Positioning System (GPS) receiver for receiving GPS signals at 1575 MHz and may include satellite navigation system circuitry for handling other satellite positioning data. In WiFi® and Bluetooth® links and other short-range wireless links, wireless signals are typically used to convey data over tens or hundreds of feet. In cellular telephone links and other long-range links, wireless signals are typically used to convey data over thousands of feet or miles. If desired, circuitry  46  may handle other wireless communications bands (e.g., a 60 GHz band, radio and television bands, etc.). 
     Transceiver circuitry  46  may be coupled to antennas  56  by front end module (FEM) circuitry  52  or other suitable control circuitry. Circuitry  52  may include matching circuits, switches, filters, power amplifiers, low noise amplifiers, and other circuitry. Switching circuitry such as switching circuitry (switch)  54  may be used to selectively couple antennas  56  to the transmitter and receiver circuitry of transceiver circuitry  46 . For example, in a configuration in which there are two antennas in device  10  such as upper antenna  56 A and lower antenna  56 B, switching circuitry  54  may be used to select which of antennas  56  is serving as a main or primary antenna for device  10 . The other (secondary) antenna need not be used or may be used only occasionally to determine whether or not the antenna assignments in device  10  should be swapped to improve performance. This type of arrangement may be used, for example, in implementing a receiver diversity scheme. Receiver (receive) diversity schemes can also be implemented by coupling each antenna in device  10  to a respective receiver and selectively activating the receivers for use in receiving appropriate signals during data reception operations. 
     With a receiver diversity scheme, control circuitry  28  (e.g., a baseband processor) may measure the signal quality for received signals from the primary antenna (and, if desired, the secondary antenna and other antennas in device  10 , if available). Examples of signal quality measurements that may be made include received power measurements, frame error rate measurements, bit error rate measurements, signal-to-noise ratio measurements, adjacent channel leakage measurements, etc. Based on this measured antenna performance data, control circuitry  28  can decide whether to continue with its current antenna assignments or whether performance would likely be improved by swapping the primary and secondary antennas using switch  54  or otherwise adjusting which antenna structures are being used in receiving signals. If, for example, measurements indicate that antenna  56 B is beginning to perform poorly as the primary antenna, switch  54  can be configured to switch antenna  56 A into use as the primary antenna or appropriate receiver circuitry  50  may be adjusted to receive signals from antenna  56 A while inactivating receiver capabilities for antenna  56 B). This type of diversity arrangement may be used for received signals only (receive diversity), for transmitted signals only (e.g., transmit diversity), or may involve for both receiver and transmitter diversity. If desired, the scheme used for receiving antennas may be different than the scheme used for transmitting signals. For example, antenna  56 B might, in some situations, be inactivated for receiving signals while continuing to be used for transmitting signals. 
     Antennas  56  may be formed using any suitable antenna types. For example, antennas  56  may include antennas with resonating elements that are formed from loop antenna structure, patch antenna structures, inverted-F antenna structures, slot antenna structures, planar inverted-F antenna structures, helical antenna structures, hybrids of these designs, etc. Different types of antennas may be used for different bands and combinations of bands. For example, one type of antenna may be used in forming a local wireless link antenna and another type of antenna may be used in forming a remote wireless link antenna. 
     With one suitable arrangement, device  10  may have antennas in regions of device  10  such as upper region  22  and lower region  24 . One or more upper antennas for device  10  such as antenna  56 A may be formed in region  22 . One or more lower antennas for device  10  such as antenna  56 B may be formed in region  24 . In devices with a compact rectangular form factor (e.g., handheld devices that are elongated along a longitudinal axis such as axis  60 ), antennas  56 A and  56 B may be located at opposing ends of the elongated device housing. In devices with other form factors such as laptop and tablet computers, wearable devices, computer monitors with integrated computers, etc., antennas may be located in other suitable regions (e.g., at the four corners of a rectangular device, on front and back surfaces, along edge regions of a device, in one or more arrays, etc.). There may be any suitable number of antennas  56  in device  10  (e.g., two or more, three or more, four or more, five or fewer, etc.). 
     The location of antennas  56  relative to input-output ports such as port  20  can give rise to a potential for electromagnetic interference. Port  20  and its associated connectors such as connectors  34  and  40  and input-output pins such as pins  36  and  38 ), may, for example, tend to radiate non-negligible amounts of electromagnetic interference when port  20  is in use. The amount of interference that is produced and the spectral composition of the radio-frequency interference signals may depend on the type of communications being handled by port  20 . For example, if port  20  is only conveying relatively slow signals such as direct-current (DC) data signals or fixed power signals, relatively minimal amounts of interference may be generated. On the other hand, if data is transmitted at a higher rate, radio-frequency signals may be generated in port  20  that couple to one or more of antennas  56 , particularly antennas  56  that are located in the vicinity of port  20 , such as lower antenna  56 B of  FIG. 2 . 
     In a typical scenario, path  32 , connectors  34  and  40  of port  20 , and cable  42  may carry one or two lanes of serial data at a data rates of 1.6 Gbps or 2.7 Gbps (e.g., when carrying video data to a display accessory). Data may, for example, be conveyed by operating one lane at 1.6 Gbps. More data may be conveyed by using a higher data rate. For example, more data may be conveyed per unit time by operating one of the lanes at 2.7 Gbps or by operating two lanes simultaneously at 1.6 Gbps each. Additional bandwidth may be provided by operating both lanes at 2.7 Gbps. In situations such as these, the digital data transmission operations associated with using data port  20  may lead to interference that can adversely affect the performance of the receiver (i.e., receiver circuitry  50 ) that is receiving radio-frequency antenna signals from antenna  56 B. Interference from high speed data (e.g., data being conveyed through port  20  at tens or hundreds of Mbps or more or Gbps or more) may, for example, cause interference with cellular telephone bands, local area network bands, satellite navigation system bands, etc. 
     If excessive radio-frequency interference is coupled from port  20  to an antenna such as antenna  56 B, device  10  may not be able to use antenna  56 B to receive signals satisfactorily. For example, incoming cellular telephone calls may not be received or, if a call is currently being received by antenna  56 B, interference from use of data port  20  may cause the call to be dropped. If interference is sufficiently strong, receiver circuitry  50  and control circuitry  28  may not be able to perform signal measurement operations to detect that antenna performance has degraded. For example, if interference is significant, incoming calls may not be properly received and control circuitry  28  may not be aware that received signal quality is poor (i.e., because no incoming signals are being received and analyzed to determine their frame error rate or to evaluate other performance metrics). When control circuitry  28  is unaware that performance is poor, control circuitry  28  may not be able to adjust switching circuitry  54  to switch upper antenna  56 A into use in place of lower antenna  56 B. Device  10  may therefore become locked in an inoperative state in which incoming wireless signals cannot be properly received so long as interference-producing data (e.g., high-speed data) is being conveyed through port  20 . 
     To avoid undesirable situations such as these, device  10  can monitor the status of port  20  for activity that might lead to interference. The amount of activity that is considered to be sufficient to warrant corrective action may be established by a default or user-adjustable setting. Any activity on port  20  may be considered to be sufficient to warrant action or any data transmission activities may be considered to be sufficient to warrant action. A threshold activity level (e.g., a threshold data transmission rate or other predetermined activity level) may also be used in determining whether port  20  is active enough to warrant corrective action. 
     As an example, device  10  can monitor the status of port  20  to determine whether data is being transmitted at a rate that is sufficient to cause interference. If, for example, port  20  is inactive (i.e., because connector  40  is not present or because no data or power is being conveyed over contacts  36  and  38 ), control circuitry  28  can conclude that there is no potential for data-induced electromagnetic interference with transceiver circuitry  46 . If, as another example, port  20  is active, but is transmitting data at a relatively low data rate (e.g., below 5 Mbps), control circuitry  28  can conclude (based on previous test characterization measurements) that the impact of the data flow through port  20  will be negligible. 
     In other situations, control circuitry  28  can identify data transmission situations that have the potential to cause undesirable interference. If, as an example, control circuitry  28  determines that input-output circuitry  28  is being used (or is about to be used) to transmit data with a high data rate (e.g., over 100 Mbps, over 1 Gbps, over 2 Gbps, etc), control circuitry  28  can proactively configure the wireless circuitry of device  10  to ensure that signals can continue to be received successfully. If, for example, device  10  is operating in a receive diversity mode in which switch  54  is being continually adjusted to ensure that an optimal one of antennas  56 A and  56 B is in use to receive signals, control circuitry  28  can transition from the receive diversity mode to a single antenna mode in which only antenna  56 A is being used to gather signals receive circuitry  50  (i.e., by adjusting receivers  50  so as to inactivate antenna  56 B for the purpose of receiving signals). In a device  10  in which only antenna  56 B is being used to receive signals (i.e., if antenna  56 B is being used in a static or nearly static antenna configuration), detection of potentially interfering activity on port  20  by control circuitry  28  may cause control circuitry  28  to switch to using only antenna  56 A to receive signals. 
     In systems in which each antenna has a respective receiver  50 , antenna selection operations can be performed by selectively activating and deactivating appropriate receivers. If desired, switching circuitry  54  may also be used in determining which antenna is being used in device  10 . 
     Illustrative steps involved in operating a device such as device  10  of  FIG. 2  in a wireless network are shown in  FIG. 3 . 
     Initially, device  10  may be operated in a first wireless communications mode (represented by state  62  in  FIG. 3 ) in which at least one antenna is being used that can potentially be affected by data port interference. For example, device  10  may be operated in a single antenna mode in which only primary antenna  56 B is being used (or is primarily being used) to handle wireless signals (e.g., to transmit and/or receive signals). If desired, device  10  may be operated in an antenna diversity mode during step  62  in which multiple antennas are being used (e.g., in a TX/RX diversity mode in which an optimum antenna to handle both transmission and reception operations is being continuously selected or an RX diversity mode in which an optimum antenna to handle data reception operations is being continuously selected). 
     In diversity-type operating modes, control circuitry  28  may monitor signal quality from the active antenna and/or may periodically or continuously make signal quality measurements with one or more alternative antennas to determine which antenna is optimal for use in handling wireless signals. With one illustrative diversity scheme, control circuitry  28  can use real time signal quality measurements (e.g., frame error rate measurements, received and transmitted signal power measurements, etc.) to determine which antenna from a set of two or more antennas such as antennas  56 A and  56 B is the optimal antenna to be used in receiving wireless signals and can select that optimum antenna for use while using a fixed antenna (e.g., antenna  56 B) as the primary or only antenna for transmitting antenna signals. Other antenna operating schemes may be used during the first operating mode (mode  62 ) if desired. These are merely illustrative examples. 
     During the operations of the first mode, there is a potential for interference to be produced due to the use of input-output port  20 . When, for example, video signals or other data signals with relatively high data rates are transmitted through input-output port  20 , one or more of the antennas in device  10  may pick up electromagnetic interference from port  20 . The affected antennas may include, for example, an antenna such as antenna  56 B of  FIG. 2  that is located in the vicinity of port  20 . As shown by dashed line  24 , the footprint of antenna  56 B may overlap some or all of input-output port  20 , which tends to make antenna  56 B sensitive to radio-frequency interference from port  20 . 
     To detect whether antenna  56 B will be affected by interference, control circuitry  28  may, during the operations of mode  62 , monitor whether or not device  10  is transmitting and/or receiving signals through input-output port  20 . Control circuitry  28  may, for example, monitor operating system functions, application software status information, or hardware-generated signals to determine whether signals are flowing through pins  36  and  38  that can potentially cause electromagnetic interference. The interference may arise, for example, from digital signals that have an associated data rate above a predetermined threshold. 
     Control circuitry  28  can conclude that interference is likely to affect wireless operations (e.g., signal reception through antenna  56 B) based on any suitable criteria. For example, control circuitry  28  can determine that interference will possibly affect wireless communications whenever connector  40  is plugged into connector  34 , whenever port  20  is active in handling power and/or data signals, when a data communications function is activated in response to invocation of an operating system function or an application function, when data communications of a particular type are detected on port  20  such as when video data is being transmitted, when data of more than a particular bandwidth is being transmitted through port  20  such as data of more than 100 Mbps, more than 500 Mbps, more than 1 Gbps, more than 2.0 Gbps, more than 2.5 Gbps, or more than another suitable high-speed data rate threshold, etc. 
     Control circuitry  28  can detect the presence of interference-producing communications through port  20  in real time as interference-producing communications begin to flow through port  20  or may detect the presence of such interference in advance by monitoring associated device operations. For example, control circuitry  28  can detect the imminent use of port  20  by an application or other system function that is preparing port  20  for use. 
     Control circuitry  28  can therefore detect the presence of interference-producing signals at a point in time that is somewhat before the point in time at which the signals are actually generated. As an example, there may be a delay of a fraction of a second or less (or seconds or more) between the point in time at which control circuitry  28  can definitively or reasonably conclude that the interference-producing signals will flow through port  20  and the point in time in which the signals flowing through port  20  actually begin to impair the proper functioning of the antenna in the vicinity of port  20  such as antenna  56 B of  FIG. 2 . 
     So long as port  20  is inactive or so long as no interference-producing signaling activities in port  20  are detected by control circuitry  28 , device  10  may continue to operate in mode  62 , as indicated by line  64  of  FIG. 3 . Control circuitry  28  can control the operation of circuitry such as front-end module circuitry  52 , switching circuitry  54 , and transceiver circuitry  46  so that an appropriate antenna is switched into use (e.g., so that the stronger of antennas  56 A and  56 B is switched into use based on measured signal quality when using RX diversity). 
     If, while operating in mode  62 , control circuitry  28  detects that port  20  is generating interference or is about to generate interference (e.g., if control circuitry  28  detects that port  20  is being used or is about to be used to transmit high speed data signals or otherwise is producing interference or has an immediate potential for producing interference), device  10  may transition to a second mode of operation (mode  66 ), as indicated by line  68 . The process of switching from the first mode of operation to the second mode of operation may be triggered by any suitable level of activity in input-output port  20  (e.g., detection that the amount of activity in input-output port  20  has exceeded a predetermined amount such as a predetermined data rate threshold of 1 Gbps, that input-output port  20  has exceeded a predetermined amount of activity by virtue of being in use rather than being inactive, that input-output port  20  has exceeded a predetermined amount of activity by virtue of transmitting video data, etc.). 
     In the second mode of operation (mode  66 ), device  10  may use an antenna or antennas that are not affected by interference from input-output port  20  and may inhibit use of the antenna (or antennas) that are affected by interference for receiving signals. If, for example, device  10  has two antennas such as upper antenna  56 A and lower antenna  56 B, device  10  may deactivate lower antenna  56 B during the operations of mode  66  or may use antenna  56 B only for transmitting signals and not for receiving signals. As an example, control circuitry  28  may adjust switching circuitry  54  so that antenna  56 A is coupled to an appropriate receiver in receivers  50  to receive radio-frequency signals or control circuitry  28  may inactivate a receiver in receivers  50  that is associated with antenna  56 B while activating a receiver in receivers  50  that is associated with antenna  56 A. 
     Whenever operating device  10  in a mode in which antenna  56 B is not used in receiving radio-frequency signals, antenna  56 A may be used in receiving radio-frequency signals and antenna  56 A (and/or antenna  56 B) may be used in transmitting data signals. When use of antenna  56 B in receiving signals has been inhibited by control circuitry  28  and transceiver circuitry  46  in this way, interference from use of input-output port  20  will not disrupt normal operation of device  10 . Incoming calls and other data can be received using the other antenna resources of device  10  such as antenna  56 A. 
     If there are three or more antennas  56  in device  10 , all but the antenna (or antennas) that are influenced by the operation of port  20  may be used in receiving incoming radio-frequency signals (e.g., in a receive diversity arrangement or MIMO arrangement), any given single antenna may be used in receiving incoming radio-frequency signals, or subset of antennas other than antenna  56 B may be used in receiving antenna signals. Radio-frequency signal transmissions may be performed during mode  66  using one antenna, using all but the antenna adjacent to port  20  (or all antennas in device  10 ) in an antenna diversity or MIMO scheme, etc. 
     During the operations of second mode  66 , control circuitry  28  may monitor the status of input-output port  20 . Control circuitry  28  may, for example, access operating system status information, application status information, hardware status information, or other information that is indicative or whether or not signals are being conveyed through input-output port  20  that may produce interference for antenna  56 B. Control circuitry  28  may, for example, determine whether or not input-output port  20  is being used or may determine whether or not video signals or other high-speed data is being transmitted through port  20 . If it is determined that input-output port  20  is not being used or if it is determined that input-output port  20  is not carrying video signals or other high speed data signals that have the potential to cause interference with the operation of antenna  56 B in receiving incoming radio-frequency signals (i.e., in response to detection of inactivity on port  20 ), control circuitry  28  can return device  10  to the operations of mode  62 , as indicated by line  70 . 
     As indicated by the state diagram of  FIG. 3 , device  10  can toggle back and forth between modes  62  and  66  during operation. If, for example, a user does not have any accessories or other external equipment plugged into input-output port  20  of device  10  or if input-output port  20  is otherwise not being used to convey data, device  10  can remain in mode  62  and all antennas in device  10  can be used in receiving signals, including antenna  56 B (when appropriate). Whenever control circuitry  28  detects that use of port  20  may impair the operation of antenna  56 B in receiving incoming radio-frequency signals, antenna  56 B can be inactivated for purposes of receiving incoming radio-frequency signals and antenna  56 A or other antenna resources in device  10  can be used in receiving incoming radio-frequency signals (mode  66 ). Whenever port  20  is no longer being used to transmit high frequency signals, device  10  can toggle back to mode  62 . 
     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: 20101202
Publication Date: 20131105
Grant Date: 20131105
Priority Date: 20101202
Inventors: COTTERILL PETER C.
SCHLUB ROBERT W.
Assignee: APPLE INC
CPC Classifications: [{"code": "H04B7/0877", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04B7/0805", "inventive": true, "first": true, "tree": "[]"}, {"code": "H04B7/0877", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04B7/06", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04B7/0805", "inventive": true, "first": true, "tree": "[]"}, {"code": "H04B7/08", "inventive": true, "first": true, "tree": "[]"}]
Family ID: 45218931