PATENT DOCUMENT

Publication Number: US-9398456-B2
Application Number: US-201414201620-A
Country: US
Kind Code: B2

Title: Electronic device with accessory-based transmit power control

Abstract:
An electronic device may be provided with wireless circuitry for transmitting and receiving wireless signals. Control circuitry may be used to adjust transmit power levels for the wireless signals and other settings for the wireless circuitry. The electronic device may be operated in conjunction with an external accessory. The accessory may be equipment that includes a dock connector, a case to enclose the electronic device, equipment that is coupled to the electronic device using a cable, or other external electronic equipment. An identifier may be stored in the accessory. The impact of the accessory on the wireless performance of the electronic device may be characterized and associated with the identifier. During operation of the electronic device, the electronic device may adjust transmit power levels and other settings based on the identifier of the accessory and based on sensor data, user input, and other information.

Claims:
What is claimed is: 
     
       1. An electronic device configured to couple to an external accessory, comprising:
 an antenna; 
 wireless radio-frequency transceiver circuitry that transmits wireless signals at a wireless transmit power level using the antenna; and 
 control circuitry that receives an identifier from the accessory and that controls the wireless radio-frequency transceiver circuitry to adjust the wireless transmit power level based on the identifier and based on transmit power commands received from a wireless base station. 
 
     
     
       2. The electronic device defined in  claim 1  further comprising a proximity sensor, wherein the control circuitry is configured to control the wireless radio-frequency transceiver circuitry to adjust the wireless transmit power level based on data from the proximity sensor. 
     
     
       3. The electronic device defined in  claim 2 , wherein the control circuitry is configured to control the wireless radio-frequency transceiver circuitry to adjust the wireless transmit power level to one of first, second, and third different transmit power levels based on the data from the proximity sensor and to one of fourth and fifth different transmit power levels based on the identifier, wherein the third and fourth transmit power levels are greater than the first, second, and third transmit power levels. 
     
     
       4. The electronic device defined in  claim 1  further comprising input-output circuitry that receives user input from a user, wherein the control circuitry is configured to control the wireless radio-frequency transceiver circuitry to adjust the wireless transmit power level based on the user input. 
     
     
       5. The electronic device defined in  claim 4  wherein the user input comprises an emergency authorization and wherein the input-output circuitry comprises circuitry that receives the emergency authorization. 
     
     
       6. The electronic device defined in  claim 4  wherein the input-output circuitry comprises a touch screen display and wherein the user input comprises an authorization received through the touch screen display. 
     
     
       7. The electronic device defined in  claim 1  wherein the accessory has a dock, the electronic device further comprising:
 a connector that is coupled to the dock. 
 
     
     
       8. The electronic device defined in  claim 1  wherein the accessory is a case, the electronic device further comprising a magnetic sensor that senses the identifier by detecting magnetic signals from the case with the magnetic sensor. 
     
     
       9. The electronic device defined in  claim 1  further comprising a sensor, wherein the control circuitry is configured to adjust the wireless transmit power based on data from the sensor. 
     
     
       10. The electronic device defined in  claim 9  wherein the sensor comprises an accelerometer. 
     
     
       11. The electronic device defined in  claim 9  wherein the sensor comprises a capacitive proximity sensor. 
     
     
       12. The electronic device defined in  claim 9  wherein the sensor comprises a light-based proximity sensor. 
     
     
       13. The electronic device defined in  claim 9  wherein the sensor comprises an audio sensor. 
     
     
       14. The electronic device defined in  claim 1  further comprising a housing with a connector port, wherein the accessory is coupled to the connector port. 
     
     
       15. The electronic device defined in  claim 1  further comprising:
 an additional antenna; and 
 switching circuitry that selectively couples the antenna and the additional antenna to the wireless radio-frequency transceiver circuitry, wherein the control circuitry is configured to couple a selected one of the antenna and the additional antenna to the wireless transceiver circuitry based on the identifier. 
 
     
     
       16. The electronic device defined in  claim 1  wherein the antenna comprises a tunable antenna and wherein the control circuitry is configured to tune the antenna based on the identifier. 
     
     
       17. The electronic device defined in  claim 1 , wherein the transmitted wireless signals comprise wireless data that is transmitted at the wireless power level to external communications equipment that is separate from the external accessory. 
     
     
       18. The electronic device defined in  claim 1 , wherein the control circuitry is configured to control the wireless radio-frequency transceiver circuitry to reduce the wireless transmit power level based on the received identifier. 
     
     
       19. A portable electronic device configured to be coupled to an external accessory in which an accessory identifier for that accessory is stored, comprising:
 a housing; 
 a display mounted in the housing; 
 a proximity sensor mounted in the housing that monitors for external objects adjacent to the housing; 
 an antenna; 
 wireless radio-frequency transceiver circuitry that transmits wireless signals at a wireless transmit power level using the antenna; 
 input-output circuitry; 
 a connector; and 
 control circuitry that receives user input from a user with the input-output circuitry and that receives the accessory identifier with the connector, wherein the control circuitry controls the wireless radio-frequency transceiver circuitry to adjust the wireless transmit power level based on the user input, the accessory identifier, and transmit power commands received from a wireless base station. 
 
     
     
       20. The portable electronic device defined in  claim 19  wherein the accessory comprises in-vehicle equipment and wherein the user input comprises an emergency responder authorization.

Description:
BACKGROUND 
     This relates generally to electronic devices and, more particularly, to electronic devices with wireless communications circuitry. 
     Electronic devices often include wireless communications circuitry. For example, cellular telephones, computers, and other devices often contain antennas and wireless transceivers for supporting wireless communications. 
     It can be challenging to achieve desired wireless communications performance targets in electronic devices, particularly when a device is portable and compact. As a device is moved to different locations in a wireless network, it may be necessary to increase and decrease the amount of power that is transmitted during wireless communications to satisfy network requirements. Regulatory bodies may also impose constraints on how much power can be transmitted by a device. At the same time, users are seeking optimum wireless performance. These constraints may conflict, but such conflicts may be difficult to resolve satisfactorily. 
     It would therefore be desirable to be able to provide improved ways for controlling wireless performance in an electronic device such as the amount of power transmitted by the electronic device during wireless communications. 
     SUMMARY 
     An electronic device may be provided with wireless circuitry. The electronic device may be a portable electronic device such as a cellular telephone or tablet computer, or may be other electronic equipment. 
     The wireless circuitry in the electronic device may include radio-frequency transceiver circuitry and one or more antennas for transmitting and receiving wireless signals. The radio-frequency transceiver circuitry may include a transceiver and a power amplifier that can be controlled in real time to adjust wireless signal transmit power levels. During operation, control circuitry may be used to adjust transmit power levels for the wireless signals and other settings for the wireless circuitry. 
     The electronic device may be operated in conjunction with an external accessory. The external accessory may be equipment that includes a dock connector, a case to enclose the electronic device, equipment that is coupled to the electronic device using a cable, or other external electronic equipment. An identifier may be stored in the external accessory. An accessory can be identified by the electronic device using the identifier that is stored in the accessory. 
     The impact of the external accessory on the wireless performance of the electronic device may be characterized and associated with the identifier. Some external accessories may influence the amount of emitted wireless power in the vicinity of the electronic device. For example, a case or an accessory with a dock may reduce emitted radiation hotspots. By taking into account the hotspot-reducing influence of attached accessories, an electronic device may be able to optimize transmitted power settings to enhance wireless performance. 
     If desired, user input from an authorized user, sensor data, commands from a wireless base station, and other data may be used in addition to the identifier to determine how to adjust wireless transmit power levels. Additional actions may also be taken in response to detection of a particular type of accessory identifier or other input. For example, antennas can be selected for use, antennas may be tuned, or other wireless settings may be adjusted by the electronic device. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of an illustrative electronic device with wireless communications circuitry in accordance with an embodiment. 
         FIG. 2  is a schematic diagram of an illustrative electronic device with wireless communications circuitry in accordance with an embodiment. 
         FIG. 3  is a diagram of illustrative circuitry for selecting between multiple antennas in accordance with an embodiment. 
         FIG. 4  is a diagram of an illustrative operating environment for a wireless electronic device that can communicate with a wireless base station and that can be coupled to an accessory device in accordance with an embodiment. 
         FIG. 5  is a diagram of illustrative display screens that may be displayed for a user in accordance with an embodiment. 
         FIG. 6  is a table showing how wireless transmit powers may be set to different levels as a function of device status in accordance with an embodiment. 
         FIG. 7  is a graph showing how wireless transmit power may be adjusted over time as device status changes during operation in accordance with an embodiment. 
         FIG. 8  is a flow chart of illustrative operations involved in controlling wireless transmit power during use of an electronic device in accordance with an embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     An electronic device such as electronic device  10  of  FIG. 1  may contain wireless circuitry. For example, electronic device  10  may contain wireless communications circuitry that operates in long-range communications bands such as cellular telephone bands and wireless circuitry that operates in short-range communications bands such as the 2.4 GHz Bluetooth® band and the 2.4 GHz and 5 GHz WiFi® wireless local area network bands (sometimes referred to as IEEE 802.11 bands or wireless local area network communications bands). Device  10  may also contain wireless communications circuitry for implementing near-field communications, communications at 60 GHz, light-based wireless communications, satellite navigation system communications, or other wireless communications. 
     An electronic device such as electronic device  10  of  FIG. 1  may be a computing device such as a laptop computer, a computer monitor containing an embedded computer, a tablet computer, a cellular telephone, a media player, or other handheld or portable electronic device, a smaller device such as a wrist-watch device, a pendant device, a headphone or earpiece device, or other wearable or miniature device, a television, a computer display that does not contain an embedded computer, a gaming device, a navigation device, an embedded system such as a system in which electronic equipment with a display is mounted in a kiosk or automobile, equipment that implements the functionality of two or more of these devices, or other electronic equipment. In the illustrative configuration of  FIG. 1 , device  10  is a portable device such as a cellular telephone, media player, tablet computer, or other portable computing device. Other configurations may be used for device  10  if desired. The example of  FIG. 1  is merely illustrative. 
     In the example of  FIG. 1 , device  10  includes a display such as display  14 . Display  14  has been mounted in a housing such as housing  12 . Housing  12 , which may sometimes be referred to as an enclosure or case, may be formed of plastic, glass, ceramics, fiber composites, metal (e.g., stainless steel, aluminum, etc.), other suitable materials, or a combination of any two or more of these materials. Housing  12  may be formed using a unibody configuration in which some or all of housing  12  is machined or molded as a single structure or may be formed using multiple structures (e.g., an internal frame structure, one or more structures that form exterior housing surfaces, etc.). 
     Display  14  may be a touch screen display that incorporates a layer of conductive capacitive touch sensor electrodes or other touch sensor components (e.g., resistive touch sensor components, acoustic touch sensor components, force-based touch sensor components, light-based touch sensor components, etc.) or may be a display that is not touch-sensitive. Capacitive touch screen electrodes may be formed from an array of indium tin oxide pads or other transparent conductive structures. 
     Display  14  may include an array of display pixels formed from liquid crystal display (LCD) components, an array of electrophoretic display pixels, an array of plasma display pixels, an array of organic light-emitting diode display pixels, an array of electrowetting display pixels, or display pixels based on other display technologies. 
     Display  14  may be protected using a display cover layer such as a layer of transparent glass or clear plastic. Openings may be formed in the display cover layer. For example, an opening may be formed in the display cover layer to accommodate a button such as button  16 . An opening may also be formed in the display cover layer to accommodate ports such as speaker port  18 . Openings such as opening  20  may be formed in housing  12  to form communications ports (e.g., an audio jack port, a digital data port, etc.). 
     A schematic diagram showing illustrative components that may be used in device  10  is shown in  FIG. 2 . As shown in  FIG. 2 , device  10  may include control circuitry such as storage and processing circuitry  30 . Storage and processing circuitry  30  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 storage and processing circuitry  30  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, application specific integrated circuits, etc. 
     Storage and processing circuitry  30  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, storage and processing circuitry  30  may be used in implementing communications protocols. Communications protocols that may be implemented using storage and processing circuitry  30  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, cellular telephone protocols, MIMO protocols, antenna diversity protocols, etc. 
     Device  10  may include input-output circuitry  44 . Input-output circuitry  44  may include input-output devices  32 . Input-output devices  32  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. Input-output devices  32  may include user interface devices, data port devices, and other input-output components. For example, input-output devices 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 (e.g., a capacitive proximity sensor and/or an infrared proximity sensor), magnetic sensors, connector port sensors that determine whether a connector such as an audio jack and/or digital data connector have been inserted in a connector port in device  10 , a connector port sensor or other sensor that determines whether device  10  is mounted in a dock, other sensors for determining whether device  10  is coupled to an accessory, and other sensors and input-output components. 
     Input-output circuitry  44  may include wireless communications circuitry  34  for communicating wirelessly with external equipment. Wireless communications circuitry  34  may include radio-frequency (RF) transceiver circuitry formed from one or more integrated circuits, power amplifier circuitry, low-noise input amplifiers, passive RF components, one or more antennas, transmission lines, and other circuitry for handling RF wireless signals. Wireless signals can also be sent using light (e.g., using infrared communications). 
     Wireless communications circuitry  34  may include radio-frequency transceiver circuitry  90  for handling various radio-frequency communications bands. For example, circuitry  34  may include transceiver circuitry  36 ,  38 , and  42 . Transceiver circuitry  36  may be wireless local area network transceiver circuitry that may handle 2.4 GHz and 5 GHz bands for WiFi® (IEEE 802.11) communications and that may handle the 2.4 GHz Bluetooth® communications band. Circuitry  34  may use cellular telephone transceiver circuitry  38  for handling wireless communications in frequency ranges such as a low communications band from 700 to 960 MHz, a midband from 1710 to 2170 MHz, and a high band from 2300 to 2700 MHz or other communications bands between 700 MHz and 2700 MHz or other suitable frequencies (as examples). Circuitry  38  may handle voice data and non-voice data. Wireless communications circuitry  34  can include circuitry for other short-range and long-range wireless links if desired. For example, wireless communications circuitry  34  may include 60 GHz transceiver circuitry, circuitry for receiving television and radio signals, paging system transceivers, near field communications (NFC) circuitry, etc. Wireless communications circuitry  34  may include satellite navigation system circuitry such as global positioning system (GPS) receiver circuitry  42  for receiving GPS signals at 1575 MHz or 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. 
     Wireless communications circuitry  34  may include antennas  40 . Antennas  40  may be formed using any suitable antenna types. For example, antennas  40  may include antennas with resonating elements that are formed from loop antenna structures, patch antenna structures, inverted-F antenna structures, slot antenna structures, planar inverted-F antenna structures, helical antenna structures, hybrids of these designs, etc. If desired, one or more of antennas  40  may be cavity-backed antennas. 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. 
     Transmission line paths may be used to couple antenna structures  40  to transceiver circuitry  90 . Transmission lines in device  10  may include coaxial cable paths, microstrip transmission lines, stripline transmission lines, edge-coupled microstrip transmission lines, edge-coupled stripline transmission lines, transmission lines formed from combinations of transmission lines of these types, etc. Filter circuitry, switching circuitry, impedance matching circuitry, and other circuitry may be interposed within the transmission lines, if desired. 
     Device  10  may contain multiple antennas  40 . One or more of the antennas may be blocked by a user&#39;s body or other external object while one or more other antennas are not blocked. If desired, control circuitry  30  may be used to select an optimum antenna to use in device  10  in real time. Control circuitry  30  may, for example, make an antenna selection based on information on received signal strength, based on sensor data (e.g., information from a proximity sensor indicating which of multiple antennas may be blocked by an external object), or based on other information. 
     With one suitable arrangement, device  10  obtains information on which external accessories are coupled to device  10 . For example, device  10  may determine whether device  10  has been mounted in a dock in an accessory, whether an accessory such as a headset or other device with a cable has been plugged into a port on device  10 , or whether device  10  is otherwise being used in conjunction with an accessory. In situations such as these, it may be desirable to take actions with device  10  that are based on the current operating environment for device  10 . As an example, device  10  may select an antenna to use based on which accessory or type of accessory is being used with device  10 , device  10  may adjust transmit power levels based on which accessory or type of accessory is being used with device  10 , or may take other actions based on which accessory or type of accessory is being used with device  10 . 
       FIG. 3  is a schematic diagram of a portion of an illustrative device that includes multiple antennas. As shown in the example of  FIG. 3 , switching circuitry such as multiplexer  100  may be used to couple antennas  40 A and  40 B to radio-frequency transceiver circuitry  90 . Control lines such as control lines  102 ,  104 , and  106  may receive control signals from control circuitry  30 . In response to information on which accessory or type of accessory is being used with device  10  or other information (e.g., information from a proximity sensor, transmit power commands from a network base stations, etc.), control circuitry  30  can issue control commands on paths such as paths  102 ,  104 , and  106 . For example, a control command issued on path  102  may be used to switch either antenna  40 A or antenna  40 B into use by transceiver  90  (i.e., to transmit and/or receive wireless antenna signals). Control paths may also be used to control the wireless transceiver circuitry of device  10  such as transceiver  90  and power amplifier  108 . In particular, a control command on path  106  may be used to adjust the output power for transmitted antenna signals produced by transceiver  90  and/or a control command on power amplifier control path  104  may be used to adjust the output power for amplified transmitted antenna signals at the output of power amplifier  108 . In general, the wireless transmit power level for device  10  may be adjusted by adjusting the output power from transceiver  90  and/or from power amplifier circuitry such as power amplifier  108 . 
       FIG. 4  is a circuit diagram of device  10  and external equipment that may be used with device  10  such as accessory  126  and wireless base station  136 . Device  10  may use radio-frequency transceiver circuitry  90  and antenna(s)  40  to communicate with wireless base station  136 . During operation, device  10  may use transceiver circuitry  90  and antenna(s)  40  to transmit wireless signals  134  to base station  136  and may use transceiver circuitry  90  and antenna(s)  40  to receive wireless signals  134 . Base station  136  may be a cellular telephone base station, a wireless local area network base station, or other external wireless equipment that supports wireless communications with device  10 . 
     Device  10  may include sensors such as proximity sensor  110 . Proximity sensor  110  may be a light-based proximity sensor, a capacitive proximity sensor, and/or a proximity sensor based on other technologies. An illustrative light-based proximity sensor may include a light emitter such as an infrared light-emitting diode and may have a light sensor such as a photodetector. A capacitive proximity sensor may have capacitor electrode structures that measure changes in capacitance due to the presence of external objects. Using proximity sensor  110 , device  10  can monitor for the presence of external objects such as object  112  in the vicinity of device  10 . For example, device  10  can use readings from proximity sensor  110  to determine when an external object such as a user&#39;s body or other object are within a given distance of device  10  and/or may obtain other proximity sensor data. 
     Electronic device  10  may operate in conjunction with one or more external electronic devices such as accessory  126 . Accessory  126  may include some or all of the components in electronic device  10  of  FIG. 2 . Examples of accessories that may be used with device  10  include a headset with an audio cable or digital cable that mates with device  10 , a speaker with an audio cable or digital cable that mates with device  10 , a clock radio with a dock that receives device  10 , a powered speaker that contains a dock that receives device  10 , a head unit, audio system, navigation system, or other electrical equipment in a vehicle that has a dock or cable that receives device  10 , a keyboard that mates with device  10 , a cover (e.g., a leather or plastic case) that receives device  10  and that may optionally have a keyboard or other component that mates with device  10 , or other external equipment. 
     Accessory  126  may have one or more connectors such as connector  120 . Connector  120  may be an audio jack connector (e.g., a tip-ring-sleeve connector, a tip-ring-ring-sleeve connector or other audio jack connector having a ⅛″ diameter or a ¼″ diameter or other suitable diameter), may be a digital data connector (e.g., a data connector with one or more digital data lines and one or more power lines such as a Universal Serial Bus connector or other connector having a differential digital data line pair and a pair of positive and ground power lines), may be a connector that supports a combination of analog and data signals on shared lines and/or on dedicated analog lines and dedicated digital lines, or may be any other suitable type of connector. Connector  120  may be mounted within a connector port in a housing for accessory  126 , may be attached to the end of a cable that is plugged into accessory  126  or that serves as a pigtail for accessory  126 , or may otherwise be coupled to accessory  126 . 
     Device  10  may have a connector such as connector  114  that mates with connector  120  of accessory  126 . Connectors such as connectors  114  and  120  may have contacts (sometimes referred to as pins). For example, connector  114  may have contacts  116  and connector  120  may have contacts  118 . There may be any suitable number of contacts in the connectors of device  10  and accessory  126 . For example, connector  114  may have four contacts  116  and connector  120  may have four mating contacts  120 . Configurations for connectors  114  and  120  that have fewer than four contacts or more than four contacts may also be used. The configuration of  FIG. 4  in which connector  114  has four contacts  116  and connector  120  has four contacts  118  is merely illustrative. 
     During operation of device  10 , wireless base station  136  may send commands to device  10  that instruct device  10  to raise or lower the transmit power level associated with wireless signals  134  that are being transmitted by radio-frequency transceiver circuitry  90  and antenna(s)  40 . If transmit powers are too low, link quality between device  10  and wireless base station  136  will be low. If, however, transmit powers are too high, device  10  may cause wireless interference that prevents other devices in the network from communicating effectively with wireless base station  136 . The commands issued by wireless base station  136  to device  10  (and other devices in the network) raise and lower transmit power to balance these concerns. The commands to raise and lower transit power levels are sometimes referred to as TPC commands or transmit power commands. 
     Device  10  may use input-output circuitry  44  to gather user input  132  from a user of device  10 . For example, a user may press one or more buttons in device  10 , may provide voice commands to device  10 , may enter information into a touch screen (e.g., by pressing on-screen buttons or otherwise selecting on-screen options on display  14 ), or may otherwise supply input to device  10 . User input  132  may be used in controlling the software running on device  10 , which, in turn, controls the operation of device  10 . 
     Device  10  may take actions that depend on the identity of accessory  126 . For example, wireless circuit adjustments and other adjustments may be made based on which type of accessory is coupled to device  10 . Accessory  126  may contain control circuitry and input-output circuitry  124 . An integrated circuit in circuitry  124  or other circuitry  124  (e.g., registers, a memory circuit, etc.) may be used to store an accessory identifier (ID). The identifier may uniquely identify accessory  126  and/or may identify accessory  126  as being part of a larger class (or classes) of device. As an example, the identifier information stored in circuitry  124  may specify that accessory  126  is a headset or a particular class of headset, may specify that accessory  126  is a dock or is a dock in a particular type of environment such as an in-vehicle dock, may specify that accessory  126  is a case or is a particular type of case (e.g., a case with a hinge, a case without a hinge, a case with a particular thickness or a particular set of radio-frequency characteristics, etc.), or may specify that accessory  126  has other characteristics. 
     If desired, the identifier may be stored in accessory  126  using one or more resistors such as resistor  122  (e.g., resistors that are shorted between contacts  118  in connector  120 ). When device  10  and accessory  126  are coupled by attaching connectors  114  and  120  together, control circuitry  30  in device  10  can evaluate the resistance values of the one or more resistors  122  in accessory  126  to determine that identifier. Magnets such as magnet  128  may also be used to store identifiers in accessories  126  (e.g., in accessories such as a case that can receive device  10 , etc.). The properties of the magnet(s) may be monitored by device  10  using magnetic sensors in device  10  such as magnetic sensor  130 . Information may be encoded based on magnet strength, magnetic polarity, magnet location within the case or other accessory, etc. 
     Regardless of how device  10  obtains identifier information from accessory  126 , the identifier that is obtained may be used to specify characteristics about accessory  126  that are used in adjusting the operation of device  10  (e.g., wireless operation, etc.). As an example, the accessory identifier may be correlated with radio-frequency properties such as the propensity of accessory  126  to attenuate wireless signal powers in the vicinity of antenna  40 . This relationship between accessory identifier and the wireless behavior of device  10  when device  10  is coupled to accessory  126  allows device  10  to control radio-frequency transmit powers for the wireless antenna signals  134  that are being transmitted by radio-frequency transceiver  90  and antenna(s)  40  based on the identity of accessory  126 . 
     To ensure that regulatory limits are met for wireless emissions in the vicinity of a user&#39;s body, device  10  may impose a wireless transmit power limit on transmitted wireless signals  134 . The transmit power limit may vary as a function of wireless frequency (or communications band) or as a function of other wireless communications parameters (e.g., communications protocol, etc.). Abiding by the transmit power limit specified by regulatory bodies ensures that device  10  will be operated safely. 
     In some situations, such as when device  10  is being held in a user&#39;s hand, pressed against a user&#39;s head, or rested on a user&#39;s lap, it may be desirable to reduce the transmit power for device  10  to ensure that regulatory limits for emitted radiation are satisfied. Proximity sensor data from proximity sensor  110  can determine when a user&#39;s body or other external object is present in the vicinity of device  10 , so that the transmit power can be reduced accordingly. 
     When device  10  is being used with certain accessories, it may be desirable to increase the transmit power to ensure that device  10  can communicate satisfactorily with wireless base stations  136  or other external wireless equipment. Consider, as an example, a scenario in which device  10  is mounted on a dock associated with accessory  126  (i.e., a dock having a dock connector such as connector  120 ). Because the dock is bulky and is associated with equipment such as a clock radio, powered set of speakers, or in-vehicle equipment, device  10  will be located far from the body of the user. The presence of the accessory therefore allows radio-frequency signals that are transmitted to decrease in intensity before potentially reaching a user. In this type of situation, it is safe to raise the wireless transmit power limit for device  10  and it is desirable to do so to improve the quality of wireless communications with external equipment such as wireless base station  136 . Signals from proximity sensor  110  may indicate that an external object is close to device  10  when device  10  is mounted in an accessory (e.g., a case or a device with a dock), but because the external object is part of an inanimate object such as the dock and is not part of a user&#39;s body, it is appropriate to raise the transmit power limit. The power-reduction response of device  10  that would otherwise be made in the presence of detecting an external object in the vicinity of sensor  110  may be suppressed. 
     Different types of accessories may have different radio-frequency characteristics. For example, in some accessories, such as certain accessories with docks, device  10  may be well isolated from contact with a user&#39;s body. In other accessories, such as cases that enclose device  10 , device  10  may be well isolated from contact with a user&#39;s body, but may not be as isolated as when device  10  is mounted to an accessory dock. The identifier in accessory  126  (in this example) can specify whether the accessory is equipment with a dock (e.g., in-vehicle equipment) or is a case. When device  10  senses that accessory  126  is an accessory of the type that has a dock, device  10  can set the maximum transmit power level to a first level. In response to sensing that accessory  126  is a case, device  10  can establish a transmit power limit at a second level that is lower than the first level. Each accessory can be characterized in advance of use with device  10  and an appropriate identifier may be stored in that accessory based on the ability of the accessory to reduce hotspots in transmitted signal powers and otherwise attenuate the power of wireless signals reaching a user. 
     In addition to controlling radio-frequency transmit powers for signals  134  based on the identity of accessory  126 , device  10  may control radio-frequency transmit powers for signals  134  based on user input  132 , based on data from proximity sensor  110 , based on commands from wireless base station  136 , and/or based on data from other sensors and circuitry in device  10 . Device  10  may also take other actions based on these inputs. For example, device  10  may take actions such as switching a desired antenna into use from a set of multiple antennas, may tune one or more antennas in device  10 , or may take other actions based on the identity of accessory  126 , based on user input  132 , based on data from proximity sensor  110 , based on commands from wireless base station  136 , and/or based on data from other sensors and circuitry in device  10 . 
     There is generally an interplay between the data received from proximity sensor  110  and other sensors, an accessory identifier, commands received from base stations  136  (e.g., transmit power commands), and data from user input  132 . Device  10  (e.g., control circuitry  30 ) may implement a hierarchy that resolves conflicts between data from different sources. As an example, if device  10  receives a TPC command from base station  136  that instructs device  10  to raise the transmit power level being used to transmit wireless signals, that command will be followed unless a proximity sensor signal from proximity sensor  110  indicates that there is an external object in the vicinity of device  10 . The presence of the external object adjacent to device  10  indicates that device  10  may be currently in use by a user who is resting device  10  on the user&#39;s leg, is holding device  10 , or is otherwise close to device  10 . In this illustrative example, the data form the proximity sensor is placed higher in the control hierarchy than the data from the wireless base station. To ensure that device  10  does not transmit signals that are too weak, even when it would be appropriate to raise output powers, information from the identifier in accessory  126  and/or user input  132  may be placed higher in the control hierarchy than data from the proximity sensor. 
     As an example, if the identifier in accessory  126  indicates that device  10  is currently mounted in a dock in an automobile while the proximity sensor in device  10  is detecting a nearby object, device  10  can conclude that the proximity sensor in device  10  is sensing the presence of the dock rather than a human body. As a result, device  10  may allow the transmit power for wireless antenna signals in device  10  to be raised above the reduced level that would otherwise be set by the proximity sensor reading. The transmit power may also, if desired, be raised above the normal transmit power limit that would be imposed for device  10 , because (in this example), it is known that device  10  (i.e., the antenna in device  10  that is transmitting the wireless signals) is well separated from the user&#39;s body. 
     As another example, a user may enter a special “emergency responder” code into device  10  or other authorization that certifies that the user is an authorized emergency responder (personnel associated with a police force, fire department, ambulance service, etc.) or is otherwise involved in an emergency situation in which temporarily elevated wireless transmit powers are appropriate. When device  10  receives the emergency responder code, device  10  may temporarily raise the transmit power limit to ensure that a satisfactory wireless communications link is maintained between device  10  and wireless base station  136 . 
       FIG. 5  shows illustrative display screens that may be displayed for a user as the user provides device  10  with user input  132  such as an emergency authorization code. Initially, display  14  of device  10  may display a screen for the user such as screen  140 . Screen  140  may contain one or more on-screen options such as option  142 . Option  142  may be selected by the user when the user believes that an emergency situation makes it appropriate to temporarily raise the wireless transmit power limit for device  10 . In response to selection of on-screen option  142 , device  10  may display screen  144  on display  14 . Screen  144  may contain instructions such as instructions  146  that direct the user to enter an authorization code using on-screen options such as on-screen buttons  148 . In response to receiving an authorized code from the user via buttons  148 , device  10  may display a screen such as screen  150  for the user. Screen  150  may allow the user to make a cellular telephone call by typing a desired telephone number into keypad keys such as keys  152  and by pressing call option  154 . Other on-screen options may be used to allow the user to communicate using device  10  if desired (e.g., text messaging options, email options, video call options, voice communications options other than traditional cellular telephone voice calls, etc.). When making the telephone call or supporting other wireless communications, device  10  may temporarily raise the wireless transmit power limit that is being used by device  10 . 
       FIG. 6  is a table showing how the maximum allowed transmit power level in device  10  may be adjusted as a function of different operating conditions in device  10 . In the example of  FIG. 6 , if a proximity sensor reading from proximity sensor  110  is high (indicating that external object  112  is close to device  10 ), the corresponding transmit power level may be set to a relatively low value of P 1 . If, the proximity sensor reading is lower (i.e., a medium value), the transmit power level may be raised to a slightly higher value of P 2  (i.e., a value above P 1 ). When proximity sensor readings are weak, external object  112  is relatively far from device  10 , so the transmit power may be set to a level of P 3  that is greater than P 2 . When device  10  is installed in an accessory of type A (e.g., a case), antenna(s)  40  are shielded from direct contact with a user by virtue of the presence of the case. As a result, less radiated power can be absorbed into the user&#39;s body and the maximum wireless transmit power for device  10  may be raised to a level P 4  that is greater than P 3 . 
     In response to detection that device  10  has been installed in an accessory of type B (e.g., in a dock in an in-vehicle device), the maximum wireless transmit power can be raised to an even higher level of P 5 , due to the large separation between antenna  40  in device  10  and the user. In emergency mode (e.g., when an emergency responder or other user enters a value emergency authorization code) or other user input  132 , device  10  can set the transmit power to a level of P 5  that is greater than level P 4  or an even higher level (as examples). 
     During operation, transmit power commands from base station  136  can be received and processed and may be used to further adjust the current output power for device  10 . For example, if the current transmit power for device  10  is P 3 , TPC commands may temporarily lower the transmit power to P 2  if deemed necessary to prevent interference in the network. As another example, if the maximum transmit power has been set to level P 5  to handle an emergency situation, power-lowering TPC commands may be temporarily ignored. Other types of transmit power control scenarios may be implemented in device  10 , if desired. The arrangement of  FIG. 6  is merely illustrative and is presented as an example of how different types of sensor data, user input, and wireless base station command data can be used in controlling wireless transmit power levels in device  10 . 
       FIG. 7  is a graph showing an illustrative scenario in which wireless transmit power P for device  10  is changed as a function of time due to changes in received TPC commands, proximity sensor data, other data on the operating conditions of device  10 , a detected accessory identifier, and/or user input. At times between t 0  and t 1 , device  10  is close to base station  136 , so device  10  is able to sustain a high quality wireless communications link between device  10  and base station  136  while using relatively low transmit powers. Base station  136  senses that device  10  is able to back off transmit power to level P 1  without unduly compromising link quality and therefore issues TPC commands that reduce transmit power to level P 1 . Between times t 1  and t 2 , device  10  moves farther from base station  136 , so base station  136  directs device  10  to increase its transmit power to level P 2 . Between times t 2  and t 3 , device  10  has been moved to a location that is remote from base station  136 , so base station  136  issues a TPC command that directs device  10  to increase wireless transmit power P to a relatively high level of P 3 . Level P 3  in this example, is the largest normally permitted transmit power for device  10  that complies with regulatory limits on emitted radiation (assuming device  10  is not installed within a case, dock, or other equipment that increases the separation between the user and the antennas in device  10 ). 
     Even though, at time t 3 , the maximum transmit power of P 3  has been requested by base station  136 , data from proximity sensor  110  may be used to override the transmit power level set by base station  136 . This is illustrated by the reduced transmit power level of P 2  that is used between times t 3  and t 4 . In this example, base station  136  directed device  10  to use transmit power P 3 , but proximity sensor  110  detected an external object at time t 3  that was located at a sufficiently close distance to dictate that the wireless transmit power for device  10  should be reduced to transmit power level P 2 . At times between t 4  and t 5 , the external object is once again located farther from device  10  and the transmit power is accordingly allowed to rise to P 3  again. If desired, operating mode information (i.e., information that device  10  is using an ear speaker and is therefore being held against the side of a user&#39;s head) may be used to adjust wireless transmit power (see, e.g., illustrative transmit power level P 1  between times t 5  and t 6 ). Reduced power level P 1  between times t 5  and t 6  may also result from detection of the user&#39;s body using a light-based proximity sensor or other sensor (e.g., an accelerometer that detects motion, a sound sensor that detects absorption of ultrasonic tones emitted by a speaker in device  10  by clothing on a user, temperature sensor that indicates that the user is holding device  10 , etc.). 
     In the  FIG. 7  example, device  10  returns to normal maximum transmit power P 3  at times between t 6  and t 7  (i.e., TPC commands from base station  136  have requested that device  10  transmit signals with its normal maximum allowed power and no nearby object is present). In this mode of operation, device  10  is fairly remote from base station  136  and must therefore increase transmit power as much as possible to sustain satisfactory communications. At times between time t 7  and t 8 , device  10  has been coupled to accessory  126 . Device  10  detects the identifier stored in accessory  126  by reading the identifier information through the connector in device  10  that is coupled to accessory  126  and/or using magnetic sensing or other identifier detection techniques. Accessory  126  partly shields the user from radiated emissions, so it is appropriate for device to further increase the transmit power level P to power P 4  in response to detection of the identifier. The type of identifier that is received can be used by device  10  to determine how much transmit power P can be increased. The ability to transmit signals at a power P 4  that is larger than the normal maximum of P 3  helps enhance wireless communications link quality while still satisfying regulatory limits on emitted radiation levels in the vicinity of device  10 . 
     At times greater than t 8  in the  FIG. 7  example, an emergency situation has made it necessary for the user to override the normal internal transmit power controls in device  10 . The user may, as an example, supply device  10  with an emergency responder&#39;s code or other authorization. When device  10  is instructed by the user input that an emergency situation is present, device  10  temporarily increases transmit power P to an elevated level of P 5  (in this example). The use of this elevated transmit power ensures that the user can communicate with base station  136 , even if the base station is sufficiently remote from device  10  that communications at lower powers such as transmit power P 3  would be unsuccessful. 
     A flow chart of illustrative steps involved in operating device  10  in a scenario in which multiple different types of data are used in determining how to control the wireless transmit power and other wireless behavior of device  10  are shown in  FIG. 8 . At step  200 , device  10  may perform monitoring operations to determine whether or not operating conditions dictate a change in wireless transmit power. Device  10  also uses wireless transceiver circuitry  90  and antenna(s)  40  to transmits signals with the currently active transmit power setting P during the operations of step  200 . Base station  136  receives and processes the transmitted signals and transmits signals to device  10  that are received by device  10 , thereby maintaining a wireless link between device  10  and base station  136 . 
     During the monitoring operations of step  200 , device  10  uses control circuitry  30  to determine whether a transmit power command has been received from base station  136  (see, e.g., line  204 ), to determine whether proximity sensor data from proximity sensor  110  has been received that indicates that an external object is close to device  10  (see, e.g., line  208 ), to determine whether an accessory identifier has been received making it appropriate to raise transmit power limits or take other actions (see, e.g., line  210 ), and to determine whether user input  132  or other data (e.g., data from other sensors or circuitry in device  10 ) has been received (see, e.g., line  206 ). Using an established data hierarchy, device  10  determines an appropriate transmit power level P to use for device  10 . The wireless transmit power P may then be updated at step  202  before operations return to step  200 , where wireless signals are transmitted using the currently effective transmit power. 
     If desired, additional actions and/or alternative actions may be taken at step  202  based on the results of the monitoring operations of step  200 . In particular, device  10  may switch a desired antenna into use based on the data collected during the monitoring operations of step  200 , may tune one or more antenna(s)  40  based on the data collected during the monitoring operations of step  200 , or may take other appropriate actions. If, as an example, device  10  determines that an accessory such as a dock has been coupled to device  10 , device  10  may tune its antenna(s) to compensate for antenna detuning resulting from the presence of the dock. As another example, if device  10  determines that an emergency situation is present, device  10  may switch one or more particular antenna(s) into use to enhance transmit power capabilities for device  10  or to otherwise optimize operation. Sensor data such as temperature data, accelerometer data, audio data, and other data may also be used in making these adjustments to the operation of device  10 , if desired. 
     The foregoing is merely illustrative and various modifications can be made by those skilled in the art without departing from the scope and spirit of the described embodiments. The foregoing embodiments may be implemented individually or in any combination.

Metadata:
Filing Date: 20140307
Publication Date: 20160719
Grant Date: 20160719
Priority Date: 20140307
Inventors: JADHAV DIGVIJAY A.
SEN INDRANIL S.
KING JONATHAN C.
Assignee: APPLE INC
CPC Classifications: [{"code": "H04M1/72409", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04M1/72527", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04W52/283", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04B2001/0416", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04W4/22", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04M2250/12", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04B1/3877", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04M1/72536", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04W12/06", "inventive": true, "first": true, "tree": "[]"}, {"code": "H04B1/04", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04W52/281", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04W52/248", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04B1/40", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04W52/247", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04W52/146", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04W52/04", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04W52/146", "inventive": true, "first": true, "tree": "[]"}, {"code": "H04M1/72418", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04M1/72409", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04M2250/12", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04W52/146", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04M1/72418", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04W52/248", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04W52/04", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04B1/3877", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04W52/281", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04M2250/12", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04W52/283", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04W12/06", "inventive": true, "first": true, "tree": "[]"}, {"code": "H04B1/04", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04W52/247", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04W4/90", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04W52/247", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04W4/90", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04W52/281", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04W52/248", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04B2001/0416", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04B1/40", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04W52/283", "inventive": true, "first": false, "tree": "[]"}]
Family ID: 54018831