PATENT DOCUMENT

Publication Number: US-8600316-B2
Application Number: US-201113080588-A
Country: US
Kind Code: B2

Title: Wireless circuits with minimized port counts

Abstract:
An electronic device has wireless communications circuitry including a triplexer. The wireless communications circuitry may be used in first and second modes. In the first mode, the device communicates in a first communications band using a transmitter in a first uplink frequency range associated with the first communications band and using a receiver in a first downlink frequency range associated with the first communications band. In the second mode, the device communicates in a second communications band using a transmitter to transmit in a second uplink frequency range associated with the second communications band and using the receiver to receive in a second downlink frequency range associated with the second communications band. Signals in the two downlink frequency ranges may pass through a common bandpass filter in the triplexer. Two additional bandpass filters in the triplexer may be used to respectively handle the two uplink frequency ranges.

Claims:
What is claimed is: 
     
       1. Wireless circuitry, comprising:
 a radio-frequency transceiver circuitry having at least first, second, and third ports, wherein the radio-frequency transceiver circuitry comprises a first transmitter that transmits signals through the first port in an first uplink frequency range associated with a first communications band, a second transmitter that transmits signals through the second port in a second uplink frequency range associated with a second communications band, and a receiver that receives signals through the third port in a first downlink frequency range associated with the first communications band and a second downlink frequency range associated with the second communications band; 
 at least one antenna; and 
 circuitry coupled between the antenna and the first, second, and third ports of the radio-frequency transceiver, wherein the circuitry comprises a triplexer having a terminal coupled to the antenna and having triplexer ports respectively coupled to the first, second, and third ports of the radio-frequency transceiver and wherein the triplexer comprises first, second, and third bandpass filters. 
 
     
     
       2. The wireless circuitry defined in  claim 1  wherein the first and second downlink frequency ranges are adjacent to one another and wherein the circuitry that is coupled between the antenna and the first, second, and third ports comprises filter circuitry that supplies signals in the first downlink frequency range and the second downlink frequency range to the third port. 
     
     
       3. The wireless circuitry defined in  claim 1  wherein the first communications bands ranges from 704 MHz to 746 MHz, wherein the second communications band ranges from 746 MHz to 787 MHz, and wherein the circuitry that is coupled between the antenna and the first, second, and third ports comprises filter circuitry that supplies signals in the first downlink frequency range and the second downlink frequency range to the third port. 
     
     
       4. The wireless circuitry defined in  claim 3  wherein the first uplink frequency range is 704 MHz to 716 MHz, wherein the first downlink frequency range is 734 to 746 MHz, wherein the second uplink frequency range is 777 MHz to 787 MHz, wherein the second downlink frequency range is 746 MHz to 756 MHz, and wherein the filter circuitry is configured to receive signals in the first uplink frequency range from the first port and is configured to receive signals in the second uplink frequency range from the second port. 
     
     
       5. The wireless circuitry defined in  claim 4  wherein the first and second downlink frequency ranges are mutually exclusive. 
     
     
       6. The wireless circuitry defined in  claim 5  wherein the first bandpass filter is coupled to the first port, the second bandpass filter is coupled to the second port, and the third bandpass filter is coupled to the third port. 
     
     
       7. The wireless circuitry defined in  claim 6  wherein the first bandpass filter is configured to pass signals ranges from 704 MHz to 716 MHz, wherein the second bandpass filter is configured to pass signals ranging from 777 MHz to 787 MHz, and wherein the third bandpass filter is configured to pass signals ranging from 734 MHz to 756 MHz. 
     
     
       8. The wireless circuitry defined in  claim 7  further comprising switching circuitry interposed between the antenna and the triplexer. 
     
     
       9. The wireless circuitry defined in  claim 1  wherein the first and second downlink frequency ranges are mutually exclusive. 
     
     
       10. The wireless circuitry defined in  claim 9  wherein the first bandpass filter is coupled to the first port, the second bandpass filter is coupled to the second port, and the third bandpass filter is coupled to the third port. 
     
     
       11. The wireless circuitry defined in  claim 10  wherein the first bandpass filter is configured to pass signals ranges from 704 MHz to 716 MHz, wherein the second bandpass filter is configured to pass signals ranging from 777 MHz to 787 MHz, and wherein the third bandpass filter is configured to pass signals ranging from 734 MHz to 756 MHz. 
     
     
       12. The wireless circuitry defined in  claim 11  further comprising switching circuitry interposed between the antenna and the triplexer. 
     
     
       13. A method for wirelessly communicating using an electronic device having a radio-frequency transceiver with first, second, and third transceiver ports, a triplexer having first, second, and third triplexer ports coupled respectively to the first, second, and third transceiver ports of the radio-frequency transceiver and having an additional triplexer port coupled to an antenna, the method comprising:
 in a first mode of operation, transmitting signals in a first uplink frequency band through the first transceiver port, the first triplexer port, the additional triplexer port, and the antenna and receiving signals in a first downlink frequency band through the antenna, the additional triplexer port, the second triplexer port, and the second transceiver port; and 
 in a second mode of operation, transmitting signals in a second uplink frequency band through the third transceiver port, the third triplexer port, the additional triplexer port, and the antenna and receiving signals in a second downlink frequency band through the antenna, the additional triplexer port, the second triplexer port, and the second transceiver port, and wherein the triplexer includes first, second, and third bandpass filters. 
 
     
     
       14. The method defined in  claim 13  wherein the first downlink frequency band includes frequencies between a first frequency and a second frequency that is greater than the first frequency, wherein the second downlink frequency band includes frequencies between a third frequency and a fourth frequency that is greater than the third frequency, and wherein the third frequency is greater than or equal to the second frequency, wherein the first downlink frequency band and the second downlink frequency band are adjacent, and wherein receiving signals in the first and second downlink frequency bands comprises receiving the first and second downlink frequency bands through the second bandpass filter. 
     
     
       15. Wireless circuitry, comprising:
 a radio-frequency transceiver circuitry having at least first, second, and third ports, wherein the radio-frequency transceiver circuitry comprises a first transmitter that transmits signals through the first port in an first uplink frequency range associated with a first communications band, a second transmitter that transmits signals through the second port in a second uplink frequency range associated with a second communications band, and a receiver that receives signals through the third port in a first downlink frequency range associated with the first communications band and a second downlink frequency range associated with the second communications band; 
 at least one antenna; and 
 a triplexer having a terminal coupled to the antenna and having triplexer ports respectively coupled to the first, second, and third ports of the radio-frequency transceiver, wherein the triplexer comprises:
 a plurality of bandpass filters, each of which is coupled to a respective one of the first, second, and third ports. 
 
 
     
     
       16. The wireless circuitry defined in  claim 15  wherein the first uplink frequency range includes frequencies higher than any frequencies in the first and second downlink frequency ranges, wherein the second uplink frequency range includes frequencies lower than any frequencies in the first and second downlink frequency ranges. 
     
     
       17. The wireless circuitry defined in  claim 16  further comprising switching circuitry interposed between the antenna and the triplexer. 
     
     
       18. The wireless circuitry defined in  claim 16  wherein the bandpass filters in the triplexer comprise first, second, and third bandpass filters, wherein the first bandpass filter is coupled to the first port, the second bandpass filter is coupled to the second port, and the third bandpass filter is coupled to the third port, wherein the first bandpass filter is configured to pass signals ranging from 777 MHz to 787 MHz, wherein the second bandpass filter is configured to pass signals ranges from 704 MHz to 716 MHz, and wherein the third bandpass filter is configured to pass signals ranging from 734 MHz to 756 MHz. 
     
     
       19. The wireless circuitry defined in  claim 18  wherein the first and second downlink frequency ranges are adjacent to one another and wherein the triplexer further comprises a plurality of inductors, each of which is coupled between a respective one of the bandpass filters and the terminal of the triplexer that is coupled to the antenna.

Description:
This application claims the benefit of provisional patent application No. 61/359,263, filed Jun. 28, 2010, which is hereby incorporated by reference herein in its entirety. 
    
    
     BACKGROUND 
     This relates generally to wireless communications circuitry, and more particularly, to circuitry in wireless electronic devices helps reduce port counts in radio-frequency circuits. 
     Electronic devices such as computers and cellular telephones are often provided with wireless communications capabilities. For example, electronic devices may use long-range wireless communications circuitry such as cellular telephone circuitry to communicate using cellular telephone bands. As spectrum is allocated to support new wireless services, it is becoming desirable for the wireless circuitry in electronic devices to support additional communications bands. For example, as new spectrum becomes available, electronic devices may need to be developed to handle communications bands at frequencies in the new spectrum and at frequencies associated with legacy bands. 
     In devices with wireless circuitry that handles multiple communications bands, it is often desirable to share limited antenna resources among multiple communications bands. In a typical antenna sharing scheme, switching circuitry and filter circuitry can be used to selectively couple an antenna to different ports in a radio-frequency transceiver. 
     Although antenna sharing schemes reduce the need for numerous antennas, the switching circuitry and filter circuitry that is used in conventional antenna sharing schemes may be complex and bulky and may exhibit undesired radio-frequency signal losses. 
     It would therefore be desirable to be able to provide improved circuitry for routing signals between radio-frequency transceiver ports and antenna structures in a wireless electronic device. 
     SUMMARY 
     An electronic device may be provided with wireless communications circuitry. The wireless communications circuitry may include a radio-frequency transceiver for handling wireless communications. The radio-frequency transceiver may have multiple ports. The ports may be used for transmitting and receiving wireless signals such as cellular telephone signals. 
     The radio-frequency transceiver may include a transmitter that transmits radio-frequency signals in a first uplink frequency range associated with a first communications band and may include a receiver that receives radio-frequency signals in a first downlink frequency range associated with the first communications band. These operations may be performed while the electronic device is in a first mode of operation. 
     In a second mode, the device may communicate in a second communications band. The radio-frequency transceiver may include a transmitter that transmits signals in a second uplink frequency range associated with the second communications band and may use the receiver to receive signals in a second downlink frequency range associated with the second communications band. 
     Signals in the two downlink frequency ranges may pass through a common bandpass filter in a triplexer. Two additional bandpass filters in the triplexer may be used to respectively handle the two uplink frequency ranges. 
     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 schematic diagram of an illustrative electronic device with wireless communications circuitry in accordance with an embodiment of the present invention. 
         FIG. 2  is a graph of illustrative communications bands that may be handled using a device of the type shown in  FIG. 1  in accordance with an embodiment of the present invention. 
         FIG. 3  is a circuit diagram of illustrative wireless communications circuitry of the type that may be used in handling the wireless communications bands of  FIG. 2  in an electronic device of the type shown in  FIG. 1  in accordance with an embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION 
     Electronic devices such as device  10  of  FIG. 1  may be provided with wireless communications circuitry. The wireless communications circuitry may be used to support wireless communications such as long-range wireless communications (e.g., communications in cellular telephone bands) and short-range communications (i.e., local area network links such as WiFi® links, Bluetooth® links, etc.). Examples of long-range (cellular telephone) bands that may be handled by device  10  include the 800 MHz band, the 850 MHz band, the 900 MHz band, the 1800 MHz band, the 1900 MHz band, the 2100 MHz band, the 700 MHz band, and other bands. The long-range bands used by device  10  may include the so-called LTE (Long Term Evolution) bands. The LTE bands are numbered (e.g., 1, 2, 3, etc.) and are sometimes referred to as E-UTRA operating bands. 
     As shown in  FIG. 1 , device  10  may include storage and processing circuitry  28 . Storage and processing 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 storage and processing 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, application specific integrated circuits, etc. 
     Storage and processing 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, functions related to communications band selection during radio-frequency transmission and reception operations, etc. To support interactions with external equipment, storage and processing circuitry  28  may be used in implementing communications protocols. Communications protocols that may be implemented using storage and processing circuitry  28  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 (multiple input multiple output) protocols, antenna diversity protocols, etc. Wireless communications operations such as communications band selection operations may be controlled using software stored and running on device  10  (i.e., stored and running on storage and processing circuitry  28  and/or input-output circuitry  30 ). 
     Input-output circuitry  30  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, etc. 
     Input-output circuitry  30  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 handle 2.4 GHz and 5 GHz bands for WiFi® (IEEE 802.11) communications and may handle the 2.4 GHz Bluetooth® communications band. Circuitry  34  may use cellular telephone transceiver circuitry  38  for handling wireless communications in cellular telephone bands such as at 850 MHz, 900 MHz, 1800 MHz, 1900 MHz, and 2100 MHz and/or the LTE bands and other bands (as examples). Circuitry  38  may handle voice data and non-voice data. 
     Wireless communications circuitry  34  may include global positioning system (GPS) receiver equipment such as 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 one or more 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 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. 
     Transceiver circuitry  90  may be used to handle multiple cellular telephone bands. Some of the bands may be adjacent to one another. A graph of the cellular telephone wireless spectrum in the vicinity of two adjacent cellular telephone communications bands (called LB and HB) is shown in  FIG. 2 . Each of the communications bands has a downlink (RX) band and an uplink (TX) band. In the example of  FIG. 2 , band LB has an uplink band (also referred to as a band, sub-band, or frequency range) that ranges from 704 MHz to 716 MHz, and a downlink band (also referred to as a band, sub-band, or frequency range) that ranges from 734 to 746 MHz. Band HB has an uplink band (also referred to as a band, sub-band, or frequency range) that ranges from 777 MHz to 787 MHz and has a downlink band (also referred to as a band, sub-band, or frequency range) that ranges from 746 MHz to 756 MHz. Band HB may be, for example, LTE band  13  and band LB may be, for example, LTE band  17 . 
     Because bands LB and HB (and, more particularly, the LB downlink band LB RX and the HB downlink band HB RX) are adjacent to one another, wireless circuitry  34  can be used to route signals associated with the LB downlink and the HB downlink bands onto a single transceiver port in transceiver circuitry  90 . This allows the number of transceiver ports that are used in device  10  to be minimized without reducing cellular band coverage. The complexity of the switching circuitry and filter circuitry that is interposed between transceiver circuitry  90  and antenna structures  40  may also be minimized. 
     Illustrative wireless circuitry  34  that may be used in device  10  of  FIG. 1  to handle bands of the type shown in  FIG. 2  and other bands is shown in  FIG. 3 . As shown in  FIG. 3 , wireless circuitry  34  may include radio-frequency transceiver  90  and antenna  40 . Antenna  40  may be implanted using antenna structures that are formed from one or more antenna elements (i.e., one or more individual antennas). Transceiver  90  may be implemented using one or more transceiver integrated circuits or other transceiver circuitry. 
     Transceiver circuitry  90  may be coupled to other storage and processing circuitry  28  (e.g., baseband integrated circuits) via path  100 . Data that is to be transmitted over antenna  40  using transmitters in transceiver circuitry  90  may be received via path  100 . Data that is received from antenna  40  using receivers in transceiver circuitry  90  may be provided to storage and processing circuitry  28  via path  100 . 
     Transceiver circuitry  90  may be coupled to antenna  40  using circuitry  136 . Circuitry  136  may include filter circuitry, switching circuitry, impedance mating circuitry, amplifiers, and other electrical components. 
     As shown in  FIG. 3 , circuitry  136  may include optional amplifier circuitry  138  such as power amplifiers  118  and  132 . Circuitry  136  may also include filter circuitry  178  and switching circuitry  162 . Filter circuitry  178 , which may sometimes be referred to as a triplexer or triplexer circuitry, may include filters  140  and radio-frequency coupling circuit (network)  176 . 
     Transceiver  90  may include transmitters and receivers. For example, transceiver  90  may include transmitter  102  for handling radio-frequency signals in uplink band LB TX (e.g., 704-716 MHz in the  FIG. 2  example) and transmitter  110  for handling radio-frequency signals in uplink band HB TX (e.g., 777-787 MHz in the  FIG. 2  example). Transmitter  102  may include tuning circuitry for tuning to a desired transmit channel in band LB TX. Transmitter  110  may include tuning circuitry for tuning to a desired transmit channel in band HB TX. Transceiver  90  may include receiver  106  for receiving signals in both downlink bands LB RX (e.g., 734-746 in the  FIG. 2  example) and HB RX (e.g., 746-756 MHz in the  FIG. 2  example). Receiver  106  may include tuning circuitry that tunes over all of the frequencies within bands LB RX and HB RX, thereby allowing receiver  106  to tune to any incoming channel in either band LB RX or band HB RX. Paths  182 ,  180 , and  184  may form transceiver ports for transceiver  90 . 
     Transmitter  102  may receive data for transmission via input path  104  and may provide corresponding radio-frequency data signals for transmission at output  114 . Optional power amplifier  116  and optional power amplifier  118  may be interposed between output  114  of transmitter  102  and terminal (triplexer port)  120  of triplexer  178 . Transmitter  110  may receive data for transmission via input path  112  and may provide corresponding radio-frequency data signals for transmission at output  128 . Optional power amplifier  130  and optional power amplifier  132  may be interposed between output  128  of transmitter  102  and terminal  134  (triplexer port) of triplexer  178 . 
     Receiver  106  may have an input  122 . One or more optional low-noise amplifiers such as amplifier  124  may be interposed between terminal  126  (triplexer port) of triplexer  178  and input  122  of receiver  106 . Receiver  106  may tune to a desired channel within the LB RX and HB RX bands and may provide a corresponding received output signal at output  108 . 
     Triplexer  178  may include filters  140  and coupling network (combining network)  176 . Network  176  may include circuitry such as inductors  154 ,  156 , and  158  that is used in combining outgoing signals from paths  144 ,  148 , and  152  onto a single path such as path  160 A and that is used in splitting incoming signals from path  160 A into respective paths  144 ,  148 , and  152 . Filter elements may be interposed between filter terminals  120 ,  126 , and  134  and respective filter terminals  144 ,  148 , and  152 . For example, filter  142  may be interposed between terminals  120  and  144 , filter  146  may be interposed between terminal  126  and terminal  148 , and filter  150  may be interposed between terminal  134  and terminal  152 . Filter  142  may pass signals in band LB TX, filter  146  may pass signals in adjacent bands LB RX and HB RX, and filter  150  may pass signals in band HB TX. Filter  142  may be a low pass filter (e.g., a filter that passes signals below frequency 716 MHz and blocks other frequencies) or a bandpass filter (e.g., a filter that passes signals in the range of 704-716 MHz and blocks signals at frequencies outside of this range). Filter  146  may be a bandpass filter (e.g., a filter that passes signals in the range of 734-756 MHz and blocks signals at frequencies outside of this range). Filter  150  may be a high pass filter (e.g., a filter that passes signals at frequencies above 777 MHz and blocks signals below 777 MHz) or a bandpass filter (e.g., a filter that passes signals in the range of 777-787 MHz while blocking frequencies outside of this range). Triplexer  178  may be implemented using a surface acoustic wave (SAW) device, a bulk acoustic wave (BAW) device, or a device using other suitable types of filtering technology. 
     Terminals  144 ,  148 , and  152  are coupled to terminal  160 A of triplexer  178  by circuitry  176 . Terminal  160 A may be connected to one of ports  160  in switching circuitry  162 . Switching circuitry  162  may be implemented by a switch or switches having multiple terminals such as terminals  160 A,  160 B,  160 C, and  160 D each of which may be selectively connected to path (terminal)  166 . Path  166  may be coupled to antenna  40 . The state of switching circuitry  162  may be controlled by storage and processing circuitry  28 , which may supply a control signal to control input  164  of switching circuitry  162 . 
     The control signal may, for example, be used to place switching circuitry  162  into different configurations depending on the communications band that is currently being used by device  10 . If for example, radio-frequency signals are being transmitted or received in one of the communications bands handled by triplexer  178 , switching circuitry  162  may be configured to connect terminal  160 A to terminal  166 . If, however, radio-frequency signals are being transmitted or received in a different band (e.g., a band handled by duplexer  168 ), switching circuitry  162  may be directed to connect path  166  to a different terminal (e.g., terminal  160 D). Duplexer circuit  168  may be used to transmit signals from path  172  to path  160 D using one of two bandpass filters  170  and may be used to convey received signals from terminal  160 D to terminal  174  using the other one of bandpass filters  172 . Other filter circuits may be selectively coupled to other terminals  160  to handle additional bands. 
     The use of wireless circuitry such as wireless circuitry  34  of  FIG. 3  may help to reduce the number of transceiver and switch ports that are used in device  10  and may help reduce the size and complexity of the filter circuitry in circuitry  136 . For example, the number of ports (switch terminals) associated with switching circuitry  162  may be minimized, because signals for four bands (LB TX, LB RX, HB RX, and HB TX) are conveyed through a single switch terminal (i.e., switch terminal  160 A). Reductions in the number of ports (switch terminals) that are used in switching circuitry  162  tend to reduce insertion losses associated with switching circuitry  162 , because switches with fewer ports and correspondingly fewer throws exhibit lower insertion losses than switches with more ports and more throws. Reception quality at the receiver circuits in transceiver circuitry  90  can be improved, because there is less loss in the path between antenna  40  and transceiver  90  when receiving signals. Reductions in insertion losses for switching circuitry  162  can also improve battery life, because reduced losses in the output path between transceiver  90  and antenna  40  allow the transmit power for transceiver  90  to be lowered for a given radiated power level. 
     Transceiver port count may be minimized by conveying signals for multiple adjacent receive bands (i.e., both LB RX and HB RX) over a single port (i.e., the port associated with path  180 ). Transmit signals for bands LB TX and HB TX may be handled using ports  182  and  184 , respectively, so a total of three transceiver ports are used in handling signals for four bands (LB TX, LB RX, HB RX, and HB TX). 
     Triplexer  140  may be more compact and may be less costly than filter circuitry based on duplexers or other filter elements. To ensure satisfactory performance when simultaneously transmitting and receiving signals, filter  146  preferably reduces out-of-band signals significantly (e.g., by 40 dB or more, by 45 dB or more, or by 50 dB or more). 
     In a typical operating scenario, device  10  is placed in either a first operating mode in which signal bands LB TX and LB RX are used (i.e., when communicating with a network that is associated with a first carrier) or a second operating mode in which signal bands HB TX and HB RX are used (i.e., when communicating with a network that is associated with a second carrier). 
     A user may, for example, desire to roam between two networks when traveling. When the user is in one location, the user may use the first carrier. When the user is in another location, the user may use the second carrier (as an example). Device  10  may sense the location of device  10  (e.g., using GPS location information, network location information, or user-supplied location information) and may automatically select an appropriate carrier to use or device  10  may be informed of an available carrier by wireless information received from the carrier or manual input. 
     Based on information on which carrier and/or frequencies are available, device  10  can use storage and processing circuitry  28  to configure switch  162  and transceiver  90 . For example, if band HB is to be used to communicate with the first carrier, switch  162  can be placed in position  160 A and transceiver  90  can be directed to activate transmitter  110  and receiver  106 . If band LB is to be used to communicate with the second carrier, switch  162  can be placed in position  160 A and transceiver  90  can be directed to activate transmitter  102  and receiver  106 . If other carriers and communications bands are to be used, the position of switch  162  may be adjusted to connect a different one of terminals  160  to path  166  and transmitters  102 ,  106 , and  110  may be temporarily not used. 
     By using filter elements with satisfactory out-of-band signal rejection properties, signal leakage during simultaneous transmission and reception operations may be avoided. For example, if transmitter  102  is active and transmitting signals in band LB TX, the ability of filter  146  to reject out-of-band signals by at least 50 dB (or by 40 dB, 45 dB, or other suitable amount) will ensure that signals in band LB RX will be received with less than 50 dB (or less than 40 dB, 45 dB, or other suitable amount) of signal leakage from band LB TX. Likewise, if transmitter  110  is active and transmitting signals in band HB TX, the ability of filter  146  to reject out-of-band signals by at least 50 dB (or by 40 dB, 45 dB, or other suitable amount) will ensure that received signals in band HB RX will contain less than 50 dB (or less than 40 dB, 45 dB, or other suitable amount) of signal leakage from band HB TX. 
     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. The foregoing embodiments may be implemented individually or in any combination.

Metadata:
Filing Date: 20110405
Publication Date: 20131203
Grant Date: 20131203
Priority Date: 20100628
Inventors: LUM NICHOLAS W.
DIMPFLMAIER RONALD W.
SANGUINETTI LOUIE J.
Assignee: APPLE INC
CPC Classifications: [{"code": "H04B1/006", "inventive": true, "first": true, "tree": "[]"}, {"code": "H04B1/006", "inventive": true, "first": true, "tree": "[]"}]
Family ID: 45352984