PATENT DOCUMENT

Publication Number: US-9497652-B2
Application Number: US-201514750534-A
Country: US
Kind Code: B2

Title: LTE/1x dual-standby with single-chip radio

Abstract:
Electronic devices may be provided that contain wireless communication circuitry. The wireless communication circuitry may include radio-frequency transceiver circuitry coupled to antennas by switching circuitry. Multiple radio access technologies may be supported. A device may include first and second antennas. Control circuitry can configure the transceiver circuitry and switching circuitry to support operation of the device in active and idle modes for each radio access technology. In some configurations, both antennas may be used to support operations associated with one of the radio access technologies. In other configurations, the first antenna may be used to support operations with a first of the radio access technologies while the second antenna is used to support operations with a second of the radio access technologies.

Claims:
What is claimed is: 
     
       1. A method, comprising:
 monitoring, by a mobile device that supports communications using a first radio access technology (RAT) and a second RAT, wireless signal quality for at least the first RAT, wherein the mobile device includes a first antenna and a second antenna; 
 using, during a first at least one page monitoring period, by the mobile device based on the monitored wireless signal quality, the first antenna to monitor a paging channel associated with the first RAT while simultaneously using the second antenna to convey wireless data traffic associated with the second RAT; and 
 using, by the mobile device subsequent to the first at least one page monitoring period, both the first antenna and the second antenna to monitor the paging channel associated with the first RAT. 
 
     
     
       2. The method of  claim 1 , further comprising:
 using, by the mobile device subsequent to the first at least one page monitoring period, both the first antenna and the second antenna to convey wireless data traffic associated with the second RAT. 
 
     
     
       3. The method of  claim 2 , wherein using both the first antenna and the second antenna to convey wireless data traffic associated with the second RAT includes using both the first antenna and the second antenna to receive Long Term Evolution (LTE) data traffic. 
     
     
       4. The method of  claim 2 , wherein using both the first and second antennas to monitor the paging channel includes temporarily interrupting reception of LTE data with the first and second antennas and, while reception of the LTE data with the first and second antennas is temporarily interrupted, using both the first and second antennas to monitor the paging channel for Code Division Multiple Access (CDMA) paging signals. 
     
     
       5. The method of  claim 1 , wherein the first RAT is a CDMA RAT and wherein the second RAT is a LTE RAT. 
     
     
       6. The method of  claim 1 , wherein the monitoring includes obtaining received signal strength indicator (RSSI) information that is indicative of channel quality for the paging channel associated with the first RAT. 
     
     
       7. The method of  claim 6 , further comprising:
 comparing the received RSSI information to a predetermined threshold; 
 wherein said using the first antenna and not the second antenna to monitor the paging channel is performed in response to determining that the received signal strength indicator exceeds the predetermined threshold. 
 
     
     
       8. The method of  claim 6 , further comprising:
 comparing the received RSSI information to a predetermined threshold; 
 wherein said using both the first antenna and the second antenna to monitor the paging channel is performed in response to determining that the received signal strength indicator does not exceed the predetermined threshold. 
 
     
     
       9. An electronic device, comprising:
 a wireless transceiver configured to support communications using a first radio access technology (RAT) and a second RAT; 
 a first antenna and a second antenna; and 
 one or more processing elements coupled to the wireless transceiver; 
 wherein the electronic device is configured to:
 use, during a first at least one page monitoring period, based on the monitored wireless signal quality, the first antenna to monitor a paging channel associated with the first RAT while simultaneously using the second antenna to convey wireless data traffic associated with the second RAT; 
 use, subsequent to the first at least one page monitoring period, both the first antenna and the second antenna to convey wireless data traffic associated with the second RAT; and 
 use, during a second at least one page monitoring period, based on the monitored wireless signal quality, both the first antenna and the second antenna to monitor the paging channel associated with the first RAT. 
 
 
     
     
       10. The electronic device of  claim 9 , wherein the first and second antennas are located at opposite ends of the electronic device. 
     
     
       11. The electronic device of  claim 9 , wherein the electronic device is configured to use both the first antenna and the second antenna to receive Long Term Evolution (LTE) data traffic during the second at least one page monitoring period. 
     
     
       12. The electronic device of  claim 9 , wherein the electronic device is configured to, during the first at least one page monitoring period, interrupt reception of LTE data with the first and second antennas and, while reception of the LTE data with the first and second antennas is temporarily interrupted, use both the first and second antennas to monitor the paging channel for Code Division Multiple Access (CDMA) paging signals. 
     
     
       13. The electronic device of  claim 9 , wherein the first RAT is a CDMA RAT and wherein the second RAT is a LTE RAT. 
     
     
       14. The electronic device of  claim 9 , wherein the first RAT is a LTE RAT and wherein the second RAT is a CDMA RAT. 
     
     
       15. The electronic device of  claim 9 , wherein the electronic device is configured to determine or receive received signal strength indicator (RSSI) information that indicates channel quality for the paging channel associated with the first RAT. 
     
     
       16. The electronic device of  claim 15 , wherein the electronic device is configured to use both the first antenna and the second antenna or use the first antenna and not the second antenna to monitor paging for the paging channel associated with the first RAT based on whether the RSSI information is above a predetermined threshold. 
     
     
       17. A non-transitory computer-readable medium having instructions stored thereon that are executable by a computing device to perform operations comprising:
 monitoring, wireless signal quality for a first radio access technology (RAT), wherein the computing device supports at least the first RAT and a second RAT and wherein the computing device includes a first antenna and a second antenna; 
 using, during a first at least one page monitoring period, based on the monitored wireless signal quality, the first antenna to monitor a paging channel associated with the first RAT while simultaneously using the second antenna to convey wireless data traffic associated with the second RAT; and 
 using, subsequent to the first at least one page monitoring period, both the first antenna and the second antenna to monitor the paging channel associated with the first RAT. 
 
     
     
       18. The non-transitory computer-readable medium of  claim 17 , wherein the first RAT is a Code Division Multiple Access (CDMA) RAT and wherein the second RAT is a Long Term Evolution (LTE) RAT. 
     
     
       19. The non-transitory computer-readable medium of  claim 17 , wherein monitoring the wireless signal quality for the first RAT includes determining or receiving signal strength information. 
     
     
       20. The non-transitory computer-readable medium of  claim 17 , wherein using the first antenna or both the first antenna and the second antenna to monitor the paging channel is based on a predetermined threshold wireless signal quality level. 
     
     
       21. An apparatus, comprising:
 one or more processing elements; and 
 one or more memories having program instructions stored thereon that are executable by the one or more processing elements to:
 use, during a first at least one page monitoring period, based on monitored wireless signal quality, a first antenna to monitor a paging channel associated with a first radio access technology (RAT) while simultaneously using a second antenna to convey wireless data traffic associated with a second RAT; 
 use, subsequent to the first at least one page monitoring period, both the first antenna and the second antenna to convey wireless data traffic associated with the second RAT; and 
 use, during a second at least one page monitoring period, based on the monitored wireless signal quality, both the first antenna and the second antenna to monitor the paging channel associated with the first RAT. 
 
 
     
     
       22. The apparatus of  claim 21 , wherein the apparatus is configured to use both the first antenna and the second antenna to receive Long Term Evolution (LTE) data traffic during the second at least one page monitoring period; and
 wherein the instructions are further executable to, during the first at least one page monitoring period, interrupt reception of LTE data with the first and second antennas and, while reception of the LTE data with the first and second antennas is temporarily interrupted, use both the first and second antennas to monitor the paging channel for Code Division Multiple Access (CDMA) paging signals. 
 
     
     
       23. The apparatus of  claim 21 , wherein the apparatus is configured to determine or receive received signal strength indicator (RSSI) information that indicates channel quality for the paging channel associated with the first RAT. 
     
     
       24. The apparatus of  claim 23 , wherein the apparatus is configured to use both the first antenna and the second antenna or use the first antenna and not the second antenna to monitor paging for the paging channel associated with the first RAT based on whether the RSSI information is above a predetermined threshold. 
     
     
       25. The apparatus of  claim 21 , wherein using the first antenna or both the first antenna and the second antenna to monitor the paging channel is based on a predetermined threshold wireless signal quality level.

Description:
PRIORITY CLAIM 
     This application is a continuation of U.S. patent application Ser. No. 14/082,093, entitled “LTE/1X Dual-Standby with Single-Chip Radio”, filed Nov. 15, 2013, which is a divisional of U.S. patent application Ser. No. 13/195,732, of the same title, filed Aug. 1, 2011, now U.S. Pat. No. 8,811,922, which claims the benefit of priority from U.S. Provisional Patent Application No. 61/476,736, of the same title, filed Apr. 18, 2011, all of which are fully incorporated herein by reference for all purposes and to the extent not inconsistent with this application. 
    
    
     BACKGROUND 
     This relates generally to wireless communication circuitry, and more particularly, to electronic devices that have wireless communication circuitry that supports multiple radio access technologies. 
     Electronic devices such as portable computers and cellular telephones are often provided with wireless communication capabilities. For example, electronic devices may use long-range wireless communication circuitry such as cellular telephone circuitry and WiMAX (IEEE 802.16) circuitry. Electronic devices may also use short-range wireless communication circuitry such as WiFi® (IEEE 802.11) circuitry and Bluetooth® circuitry. 
     In some devices, it may be desirable to support multiple radio access technologies. For example, it may be desirable to support newer radio-access technologies for handling data sessions and older radio-access technologies for supporting voice calls. Examples of different radio-access technologies that have been used in cellular telephones include Global System for Mobile Communications (GSM), Universal Mobile Telecommunications System (UMTS), Code Division Multiple Access (CDMA) (e.g., CDMA2000 including standards such as CDMA2000 1XRTT), and Long Term Evolution (LTE). 
     In theory, an electronic device may support any number of desired radio access technologies by incorporating sufficient hardware resources into the device. For example, a device may operate an independent wireless circuit and a dedicated antenna for each radio access technology. In practice, however, such a scheme may be impractical. Besides the inefficiency of including a different radio chipset and antenna for each supported radio-access technology, this approach may not guarantee immunity from interference among the various radio access technologies. 
     It would therefore be desirable to be able to provide improved ways in which to support multiple radio access technologies in an electronic device. 
     SUMMARY 
     Electronic devices may be provided that contain wireless communication circuitry. The wireless communication circuitry may include radio-frequency transceiver circuitry coupled to antennas using switching circuitry. Control circuitry may be used to adjust the configuration of the radio-frequency transceiver circuitry and the switching circuitry. 
     The wireless communication circuitry may support operations using multiple radio access technologies. The antennas may include first and second antennas. The control circuitry can provide the transceiver circuitry and switching circuitry with dynamic control signals that configure the electronic device to support various combinations of active and idle mode operation. For example, the transceiver circuitry and switching circuitry may be configured to allow both the first and second antennas to be simultaneously used to support operations for a particular radio access technology or may be configured to allow the first antenna to be used in supporting a first radio access technology while the second antenna is used in supporting the second radio access technology. 
     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 with wireless communication circuitry in accordance with an embodiment of the present invention. 
         FIG. 2  is a schematic diagram of a wireless network including a base station and an illustrative electronic device with wireless communication circuitry in accordance with an embodiment of the present invention. 
         FIG. 3  is a diagram of illustrative wireless circuitry that may be used in an electronic device in accordance with an embodiment of the present invention. 
         FIG. 4  is a diagram showing various modes of operation that may be used in a wireless electronic device in accordance with an embodiment of the present invention. 
         FIG. 5  is a circuit diagram showing illustrative circuitry that may be used in implementing a wireless electronic device in accordance with an embodiment of the present invention. 
         FIG. 6  is a table showing illustrative possible modes of operation for an electronic device with multiple antennas that supports operations with multiple radio access technologies in accordance with an embodiment of the present invention. 
         FIG. 7  is a timing diagram showing how an electronic device may support operation in an idle mode for a first radio access technology using one antenna while supporting operation in an idle mode for a second radio access technology using another antenna in accordance with an embodiment of the present invention. 
         FIG. 8  is a timing diagram showing how an electronic device may support an active data session using a first radio access technology while periodically using one of the antennas in the device to monitor a paging channel associated with a second radio access technology in accordance with an embodiment of the present invention. 
         FIG. 9  is a timing diagram showing how an electronic device may monitor a paging channel associated with a first radio access technology while periodically being adjusted to use multiple antennas to monitor a paging channel associated with a second radio access technology in accordance with an embodiment of the present invention. 
         FIG. 10  is a timing diagram showing how an electronic device may operate an active mode for a first radio access technology while periodically being interrupted to support use of multiple antennas to monitor a paging channel associated with a second radio access technology in accordance with an embodiment of the present invention. 
         FIG. 11  is a timing diagram showing how an electronic device may transition from an active mode associated with a first radio access technology that uses multiple antennas to an active mode associated with a second radio access technology that uses a single antenna in accordance with an embodiment of the present invention. 
         FIG. 12  is a timing diagram showing how an electronic device may transition from an active mode associated with a first radio access technology to an active mode associated with a second radio access technology that uses two antennas in accordance with an embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION 
     Electronic devices may be provided with wireless communication circuitry. The wireless communication circuitry may be used to support multiple radio access technologies (communications protocols). For example, an electronic device may support communications with a Global System for Mobile Communications (GSM) radio access technology, a Universal Mobile Telecommunications System (UMTS) radio access technology, a Code Division Multiple Access (CDMA) radio access technology (e.g., CDMA2000 1XRTT or other CDMA radio access technologies), a Long Term Evolution (LTE) radio access technology, and/or other radio access technologies. 
     In some embodiments, an electronic device may be described that supports at least two radio access technologies such as LTE and CDMA2000 1XRTT (sometimes referred to herein as “1X”). Other radio access technologies may be supported if desired. The use of a device that supports two radio access technologies such as LTE and 1X radio access technologies is merely illustrative. 
     The two (or more) radio access technologies for the electronic device may be supported using shared wireless  30  communication circuitry such as shared radio-frequency transceiver circuitry and a common baseband processor  6  integrated circuit (sometimes referred to as a “radio”). 
     The electronic device may have multiple antennas. For example, the electronic device may have a pair of cellular telephone antennas. The antennas may be coupled to the shared wireless communication circuitry using switching circuits and other radio-frequency front-end circuitry in the wireless circuitry of the electronic device. The wireless circuitry can be configured in real time depending on the desired mode of operation for the device. 
     When configured to support normal LTE operations, each of the antennas in the device may be used in receiving a corresponding LTE data stream. The simultaneous use of two antennas to receive two LTE data streams (a type of arrangement that is sometimes referred to as receiver diversity or receive diversity) helps to improve received data rates. Accordingly, the use of receive diversity is specified by the LTE protocol. 
     To avoid missing incoming 1X calls, a 1X paging channel may be monitored once per 1X paging cycle. To ensure that disruption to an active LTE data session is minimized, 1X page monitoring operations can be performed by temporarily using one of the antennas for 1X page monitoring while the other of the antennas continues to be used for receiving LTE data. In some situations, received signal strength in the 1X paging channel is low. In these situations, both of the antennas can be temporarily used in receiving 1X paging channel signals. After the 1X paging channel has been monitored for a desired time period (sometimes referred to as a 1X wake period), the antennas  30  can again both be used for LTE data. 
     This antenna allocation scheme may be performed  7  continuously during operation of the electronic device. Both antennas may be used for LTE traffic during periods of time in which the 1X paging channel does not need to be monitored. When the time arrives for monitoring the 1X paging channel, one or both of the antennas being used to handle LTE traffic can be temporarily used for monitoring the 1X paging channel. 
     An illustrative electronic device of the type that may be used to support multiple radio access technologies is shown in  FIG. 1 . Electronic device  10  may be a portable electronic device or other suitable electronic device. For example, electronic device  10  may be a laptop computer, a tablet computer, a somewhat smaller device such as a wristwatch device, pendant device, headphone device, earpiece device, or other wearable or miniature device, a cellular telephone, a media player, etc. 
     Device  10  may include a housing such as housing  12 . Housing  12 , which may sometimes be referred to as a case, may be formed of plastic, glass, ceramics, fiber composites, metal (e.g., stainless steel, aluminum, etc.), other suitable materials, or a combination of these materials. In some situations, parts of housing  12  may be formed from dielectric or other low-conductivity material. In other situations, housing  12  or at least some of the structures that make up housing  12  may be formed from metal elements. 
     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   30  may include image pixels formed from light-emitting diodes (LEDs), organic LEDs (OLEDs), plasma cells, electronic ink 8 elements, liquid crystal display (LCD) components, or other suitable image pixel structures. A cover glass layer may cover the surface of display  14 . Portions of display  14  such as peripheral regions  201  may be inactive and may be devoid of image pixel structures. Portions of display  14  such as rectangular central portion  20 A (bounded by dashed line  20 ) may correspond to the active part of display  14 . In active display region  20 A, an array of image pixels may be used to display images for a user. 
     The cover glass layer that covers display  14  may have openings such as a circular opening for button  16  and a speaker port opening such as speaker port opening  18  (e.g., for an ear speaker for a user). Device  10  may also have other openings (e.g., openings in display  14  and/or housing  12  for accommodating volume buttons, ringer buttons, sleep buttons, and other buttons, openings for an audio jack, data port connectors, removable media slots, etc.). 
     Housing  12  may include a peripheral conductive member such as a bezel or band of metal that runs around the rectangular outline of display  14  and device  10  (as an example). The peripheral conductive member may be used in forming the antennas of device  10  if desired. 
     Antennas may be located along the edges of device  10 , on the rear or front of device  10 , as extending elements or attachable structures, or elsewhere in device  10 . With one suitable arrangement, which is sometimes described herein as an example, device  10  may be provided with one or more antennas at lower end  24  of housing  12  and one or more antennas at upper end  22  of housing  12 . Locating antennas  30  at opposing ends of device  10  (i.e., at the narrower end regions of display  14  and device  10  when device  10  has an 9 elongated rectangular shape of the type shown in  FIG. 1 ) may allow these antennas to be formed at an appropriate distance from ground structures that are associated with the conductive portions of display  14  (e.g., the pixel array and driver circuits in active region  20 A of display  14 ). 
     If desired, a first cellular telephone antenna may be located in region  24  and a second cellular telephone antenna may be located in region  22 . Antenna structures for handling satellite navigation signals such as Global Positioning System signals or wireless local area network signals such as IEEE 802.11 (WiFi®) signals or Bluetooth® signals may also be provided in regions  22  and/or  24  (either as separate additional antennas or as parts of the first and second cellular telephone antennas). Antenna structures may also be provided in regions  22  and/or  24  to handle WiMAX (IEEE 802.16) signals. 
     In regions  22  and  24 , openings may be formed between conductive housing structures and printed circuit boards and other conductive electrical components that make up device  10 . These openings may be filled with air, plastic, or other dielectrics. Conductive housing structures and other conductive structures may serve as a ground plane for the antennas in device  10 . The openings in regions  22  and  24  may serve as slots in open or closed slot antennas, may serve as a central dielectric region that is surrounded by a conductive path of materials in a loop antenna, may serve as a space that separates an antenna resonating element such as a strip antenna resonating element or an inverted-F antenna resonating element such as  30  an inverted-F antenna resonating element formed from part of a conductive peripheral housing structure in device  10  from  10  the ground plane, or may otherwise serve as part of antenna structures formed in regions  22  and  24 . 
     Antennas may be formed in regions  22  and  24  that are identical (i.e., antennas may be formed in regions  22  and  24  that each cover the same set of cellular telephone bands or other communications bands of interest). Due to layout constraints or other design constraints, it may not be desirable to use identical antennas. Rather, it may be desirable to implement the antennas in regions  22  and  24  using different designs (e.g., using different antenna types and/or designs that exhibit different gains). For example, the first antenna in region  24  may cover one set of cellular telephone bands of interest and the second antenna in region  22  may cover a different set of cellular telephone bands of interest (as an example). Tuning circuitry may be used to tune an antenna in real time to cover either a first subset of bands, or a second subset of bands, and thereby cover all bands of interest. 
     If desired, an antenna selection control algorithm that runs on the circuitry of device  10  can be used to automatically select which antenna(s) are used in device  10  in real time. The antennas may, for example, contain a primary antenna (e.g., an antenna in region  24  that exhibits a first gain) and a secondary antenna (e.g., an antenna in region  24  that exhibits a second gain that is less than the first gain). The antenna selection control algorithm may configure circuitry in device  10  so that the primary antenna is connected to a first port associated with a baseband processor and so that the secondary antenna is connected to  30  a second port associated with the baseband processor or vice versa. Antenna selections may, for example, be based on the evaluated signal quality of received signals. In addition to selecting which antenna(s) are to be used in receiving signals, the circuitry of device  10  may be used in adjusting the transceiver circuitry and baseband processor circuitry of device  10 . For example, the circuitry of device  10  may be temporarily configured so that one or both of the antennas is used in monitoring a 1X paging channel for incoming 1X paging signals. 
     Device  10  may use any suitable number of antennas (e.g., two or more antennas, three or more antennas, etc.), but configurations in which two antennas are used are sometimes described herein as an example. Device  10  may use antennas that are substantially identical (e.g., in band coverage, in efficiency, etc.), or may use other types of antenna configurations. 
     A schematic diagram of a system in which electronic device  10  may operate is shown in  FIG. 2 . As shown in  FIG. 2 , system  11  may include wireless network equipment such as base station  21 . Base stations such as base station  21  may be associated with a cellular telephone network or other wireless networking equipment. Device  10  may communicate with base station  21  over wireless link  23  (e.g., a cellular telephone link or other wireless communication link). 
     Device  10  may include control circuitry such as 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  and other control circuits such as control circuits in wireless communication circuitry  34  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, power management units, audio codec chips, 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, etc. To support interactions with external equipment such as base station  21 , 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, IEEE 802.16 (WiMAX) protocols, cellular telephone protocols such as the Long Term Evolution (LTE) protocol, Global System for Mobile Communications (GSM) protocol, Code Division Multiple Access (CDMA) protocol, and Universal Mobile Telecommunications System (UMTS) protocol, etc. 
     Circuitry  28  may be configured to implement control algorithms for device  10 . The control algorithm may be used to control radio-frequency switching circuitry, transceiver circuitry, and other device resources. For example, the control algorithm may be used to configure wireless circuitry  34  to switch a particular antenna into use for transmitting and/or receiving signals or may switch multiple antennas into use simultaneously. The control algorithm may also be used to activate and deactivate transmitters and receivers, to tune transmitters and receivers to desired frequencies, to implement timers, to compare measured device operating parameters to predetermined criteria, etc. 
     In some scenarios, circuitry  28  may be used in gathering sensor signals and signals that reflect the quality of received signals (e.g., received pilot signals, received paging signals, received voice call traffic, received control channel signals, received data traffic, etc.). Examples of signal quality measurements that may be made in device  10  include bit error rate measurements, signal-to-noise ratio measurements, measurements on the amount of power associated with incoming wireless signals, channel quality measurements based on received signal strength indicator (RSSI) information (RSSI measurements), channel quality measurements based on received signal code power (RSCP) information (RSCP measurements), reference symbol received power (RSRP measurements), channel quality measurements based on signal-to-interference ratio (SINR) and signal-to-noise ratio (SNR) information (SINR and SNR measurements), channel quality measurements based on signal quality data such as Ec/Io or Ec/No data (Ec/Io and Ec/No measurements), etc. This information and other data may be used in controlling how the wireless circuitry of device  10  is configured and may be used in otherwise controlling and  30  configuring device  10 . 
     Input-output circuitry  30  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 circuitry  30  may include input-output devices  32 . Input-output devices  32  may include touch screens, buttons, joysticks, click wheels, scrolling wheels, touch pads, key pads, keyboards, microphones, speakers, tone generators, vibrators, cameras, sensors, light-emitting diodes and other status indicators, data ports, etc. A user can control the operation of device  10  by supplying commands through input-output devices  32  and may receive status information and other output from device  10  using the output resources of input-output devices  32 . 
     Wireless communication 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, and other circuitry for handling RF wireless signals. 
     Wireless communication circuitry  34  may include satellite navigation system receiver circuitry such as Global Positioning System (GPS) receiver circuitry  35  (e.g., for receiving satellite navigation system signals at 1575 25 30 MHz). Transceiver circuitry  36  may handle associated bands for WiFi® (IEEE 802.11) communications, for example, 2.4 GHz and 5 GHz bands, and may handle the 2.4 GHz Bluetooth® communications band. Circuitry  34  may use cellular telephone transceiver circuitry  38  for handling wireless communication in cellular telephone bands such as bands at 700 MHz, 850 MHz, 900 MHz, 1800 MHz, 1900 MHz, and 2100 MHz or other cellular telephone bands of interest. Wireless communication circuitry  34  can include circuitry for other short-range and long-range wireless links if desired (e.g., WiMAX circuitry, etc.). Wireless communication circuitry  34  may, for example, include, wireless circuitry for receiving radio and television signals, paging circuits, etc. 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 communication circuitry  34  may include antennas  40 . Antennas  40  may be formed using any suitable types of antenna. For example, antennas  40  may include antennas with resonating elements that are formed from loop antenna structures, patch antenna structures, inverted-F antenna structures, closed and open slot antenna structures, planar inverted-F antenna structures, helical antenna structures, strip antennas, monopoles, dipoles, 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 (e.g., for handling WiFi® traffic or other wireless local area network traffic) and another type of antenna may be used in forming a remote wireless link antenna (e.g., for handling cellular network traffic such as voice calls and data sessions). As described in connection with  FIG. 1 , there may be multiple cellular telephone antennas in device  10 . For example, there may be one cellular telephone antenna in region  24  of device  10  and another cellular telephone antenna in region  22  of device  30   10 . These antennas may be fixed or may be tunable. 
     Device  10  can be controlled by control circuitry that is configured to store and execute control code for implementing control algorithms. As shown in  FIG. 3 , control circuitry  42  may include storage and processing circuitry  28  (e.g., a microprocessor, memory circuits, etc.) and may include baseband processor integrated circuit  58 . Baseband processor  58  may form part of wireless circuitry  34  and may include memory and processing circuits (i.e., baseband processor  58  may be considered to form part of the storage and processing circuitry of device  10 ). 
     Baseband processor  58  may provide data to storage and processing circuitry  28  (e.g., a microprocessor, nonvolatile memory, volatile memory, other control circuits, etc.) via path  48 . The data on path  48  may include raw and processed data associated with wireless (antenna) performance metrics for received signals such as received power, transmitted power, frame error rate, bit error rate, channel quality measurements based on received signal strength indicator (RSSI) information, channel quality measurements based on received signal code power (RSCP) information, channel quality measurements based on reference symbol received power (RSRP) information, channel quality measurements based on signal-to-interference ratio (SINR) and signal-to-noise ratio (SNR) information, channel quality measurements based on signal quality data such as Ec/Io or Ec/No data, information on whether responses (acknowledgements) are being received from a cellular telephone tower corresponding to requests from the electronic device, information on whether a network access procedure has succeeded, information on how many retransmissions are being requested over a cellular link between the electronic device and a cellular tower, information on whether a loss of signaling message has been received, information on whether paging signals have been successfully received, and other information that is reflective of the performance of wireless circuitry  34 . This information may be analyzed by storage and processing circuitry  28  and/or processor  58  and, in response, storage and processing circuitry  28  (or, if desired, baseband processor  58 ) may issue control commands for controlling wireless circuitry  34 . For example, storage and processing circuitry  28  may issue control commands on path  52  and path  50  and/or baseband processor  58  may issue commands on path  46  and path  51 . 
     Wireless circuitry  34  may include radio-frequency transceiver circuitry such as radio-frequency transceiver circuitry  60  and radio-frequency front-end circuitry  62 . Radio-frequency transceiver circuitry  60  may include one or more radio-frequency transceivers such as transceivers  57  and  63 . Some transceivers may include both a transmitter and a receiver. If desired, one or more transceivers may be provided with receiver circuitry, but no transmitter circuitry (e.g., to use in implementing receive diversity schemes). As shown in the illustrative configuration of  FIG. 3 , transceiver  57  may include a transmitter such as transmitter  59  and a receiver such as receiver  61  and transceiver  63  may include a transmitter such as transmitter  67  and a receiver such as receiver  65 . 
     Baseband processor  58  may receive digital data that is to be transmitted from storage and processing circuitry  28  and may use path  46  and radio-frequency transceiver circuitry  60  to transmit corresponding radiofrequency signals. Radio-frequency front end  62  may be coupled between radio-frequency transceiver  60  and antennas  40  and may be used to convey the radio-frequency signals that are produced by radio-frequency transceiver circuitry  60  to antennas  40 . Radio-frequency front end  62  may include radio-frequency switches, impedance matching circuits, filters, and other circuitry for forming an interface between antennas  40  and radio-frequency transceiver  60 . 
     Incoming radio-frequency signals that are received by antennas  40  may be provided to baseband processor  58  via radio-frequency front end  62 , paths such as paths  54  and  56 , receiver circuitry in radio-frequency transceiver  60 , and paths such as path  46 . Path  54  may, for example, be used in handling signals associated with transceiver  57 , whereas path  56  may be used in handling signals associated with transceiver  63 . Baseband processor  58  may convert received signals into digital data that is provided to storage and  20  processing circuitry  28 . Baseband processor  58  may also extract information from received signals that is indicative of signal quality for the channel to which the transceiver is currently tuned. For example, baseband processor and/or other circuitry in control circuitry  42  may analyze received signals to produce bit error rate measurements, measurements on the amount of power associated with incoming wireless signals, strength indicator (RSSI) information, received signal code power (RSCP) information, reference symbol received power (RSRP) information, signal-to-interference ratio (SINR) information, signal-to-noise ratio (SNR) information, channel quality measurements based on signal quality data such as Ec/Io or Ec/No data, etc. 
     Radio-frequency front end  62  may include switching circuitry. The switching circuitry may be configured by control signals received from control circuitry  42  (e.g., control signals from storage and processing circuitry  28  via path  50  and/or control signals from baseband processor  58  via path  51 ). The switching circuitry may include a switch (switch circuit) that is used to connect transceiver  57  to antenna  40 B and transceiver  63  to antenna  40 A or vice versa. Radio-frequency transceiver circuitry  60  may be configured by control signals received from storage and processing circuitry over path  52  and/or control signals received from baseband processor  58  over path  46 . 
     The number of receivers and antennas that are used may depend on the operating mode for device  10 . For example, in normal LTE operations, antennas  40 A and  40 B may be used with respective receivers  61  and  65  to implement a receive diversity scheme for device  10 . With this type of arrangement, two LTE data streams may be simultaneously received and processed using baseband processor  58 . When it is desired to monitor a 1X paging channel for incoming 1X pages, one or both of the antennas may be temporarily used in receiving 1X paging channel signals. 
     Control circuitry  42  may be used to run software for handling more than one radio access technology. For example, baseband processor  58  may include memory and control circuitry for implementing multiple protocol stacks  590  such as protocol stack 1X and protocol stack LTE. Protocol stack 1X may be associated with a first radio access technology such as CDMA2000 1XRTT (as an example) Protocol stack LTE may be associated with a second radio access technology such as LTE (as an example). During operation, device  10  may use protocol stack 1X to handle 1X functions and may use protocol stack LTE to handle LTE functions. Additional protocol stacks, additional transceivers, additional antennas  40 , and other additional hardware and/or software may be used in device  10  if desired. The arrangement of  FIG. 3  is merely illustrative. 
     It may be desirable to minimize the cost and complexity of device  10  by implementing the wireless circuitry of  FIG. 3  using an arrangement in which baseband processor  58  and radio-transceiver circuitry  60  can be used to support both LTE and 1X traffic. 
     The 1X radio access technology may generally be used to carry voice traffic, whereas the LTE radio access technology may generally be used to carry data traffic. To ensure that 1X voice calls are not interrupted due to LTE data traffic, 1X operations may take priority over LTE operations. To ensure that operations such as monitoring a 1X paging channel for incoming paging signals do not unnecessarily disrupt LTE operations, control circuitry  42  can, whenever possible, configure the wireless circuitry of device  10  so that wireless resources are shared between LTE and 1X functions. 
     When a user has an incoming 1X call, the 1X network may send device  10  a paging signal (sometimes referred to as a page) on the 1X paging channel using base station  21 . When device  10  detects an incoming page, device  10  can take suitable actions (e.g., call establishment procedures) to set up and receive the incoming 1X call. Pages are typically sent several times at fixed intervals by the network, so that devices such as device  10  will have multiple opportunities to successfully receive a page. 
     Proper 1X page reception requires that the wireless circuitry of device  10  be periodically tuned to the 1X paging channel. If the transceiver circuitry  60  fails to tune to the 1X paging channel or if the 1X protocol stack in baseband processor  58  fails to monitor the paging channel for incoming pages, 1X pages will be missed. On the other hand, excessive monitoring of the 1X paging channel may have an adverse impact on an active LTE data session. 
     To conserve power, it may be desirable for the 1X and LTE protocol stacks to support idle mode operations (sometimes referred to as sleep mode functionality). During 1X idle mode, 1X voice operations that can be supported include decoding/monitoring the quick paging channel (Q-PCH) when this feature has been enabled by the network operator, decode/monitor the paging channel, re-registering the device (if the device moves out of its previous registration zone), initiating a system scan when a device enters an out-of-service condition, and reading overhead messages on the network control channel (e.g., messages conveying information such as base station identifier information, network identifier information, information on which optional features have been enabled by the network operator, etc.). 
     Three potential operating states may be associated with idle mode operation: wake mode, sleep mode, and out-of-service sleep mode. 
     When in wake mode, the device is monitored for pages from the network and is monitored to determine whether device  10  is in service. If the device is not receiving a page and is in service, the device may be placed in sleep mode. If the device is out of service, a system scan may be 30 performed to identify an available network. If no service is available, an out-of-service indicator may be displayed and the device may be placed in the out-of-service sleep mode for a period of time. Upon awakening from the out-of-service sleep mode, the device can once again search for service. If service is detected, the device may be placed in sleep mode. 
     Periodically, the device should be awakened from sleep mode into wake mode. If the device receives a page during wake mode, a communication link may be established. For example, in a 1X network, call setup operations may be performed to establish a 1X call (e.g., a voice call). Once the call is complete, the device may be returned to sleep mode. 
     This sleep-wake paging cycle may be repeated continuously during operation of device  10 . Each paging cycle, the device may be awakened for a period of time to monitor the paging channel for incoming pages. To conserve power, the device is then returned to sleep mode unless an incoming page is detected. 
     Device  10  can support active and idle mode operations for both the 1X and LTE radio access technologies. The ability of device  10  to support both 1X and LTE operations concurrently using wireless circuitry  34  and control circuitry  42  depends on the 1X and LTE modes of operation. 
     Consider, as an example, the situation in which baseband processor  58  and protocol stack 1X are being used to support 1X operations in idle mode while baseband processor  58  and protocol stack LTE are being used to support LTE operations in either idle mode or active mode. If the signal strength on the 1X paging channel is sufficient, one of the antennas in device  10  (e.g., antenna  40 B or  40 A of  FIG. 3 ) may be temporarily used for 1X paging channel monitoring operations, rather than for LTE operations. Although this temporarily occupies one of the two antennas that are normally used to implement receive diversity for LTE operations, the remaining antenna in wireless circuitry  34  may still be used to handle LTE traffic. Environments where 1X paging signal strength is sufficient to allow incoming pages to be received using only a single 1X antenna therefore allow device  10  to operate in either LTE idle or active modes while simultaneously operating in 1X idle mode. 
     In environments in which device  10  is able to support active 1X operations using a single antenna (i.e., because 1X signal strengths are sufficiently strong), the remaining antenna may be used to support LTE idle mode operations. 
       FIG. 4  is a state diagram showing how device  10  may transition between different states during operation. During normal operations in which LTE traffic is being conveyed between device  10  and network  23 , device  10  may use both antennas (e.g., antennas  40 A and  40 B of  FIG. 3 ), as illustrated by state  100 . The simultaneous use of two antennas allows device  10  to implement a receive diversity scheme that is compliant with LTE protocols. During the operations of state  100 , protocol stack LTE may be used in receiving and processing two separate incoming streams of LTE traffic. For example, receiver  61  and one of antennas  40  may be used in receiving a first LTE traffic stream and receiver  65  and a second of antennas  40  may be used in receiving a second LTE traffic stream. Baseband processor  58  may be provided with these two parallel LTE data streams over path  46  and may combine the incoming traffic into data for circuitry in device  10  such as storage and processing circuitry  28 . In configurations in which device  10  uses a single radio-frequency transmitter (e.g., transmitter  59 ) for transmitting LTE data, circuitry  42  may configure radiofrequency transceiver circuitry  60  and radio-frequency front-end circuitry  62  so that the transmitted signals from transmitter  59  are routed to either antenna  40 A or antenna  40 B. LTE dual-antenna idle mode operations may also be performed in state  100 . 
     To ensure that device  10  does not miss incoming 1X calls, device  10  may periodically transition to a state in which some or all LTE functionality is reduced and in which 1X page monitoring activities are performed. Control circuitry  42  of device  10  may, for example, periodically transition device  10  to state  102  or state  104  of  FIG. 4 . 
     Control circuitry  42  may use signal quality measurements (e.g., received signal strength indicators or other measurements of received signal quality) to determine whether to transition to state  102  or state  104 . If signal quality is sufficient, device  10  may transition to state  102 , where one antenna is used for LTE and one antenna is used for 1X (e.g., 1X active mode operations or 1X page monitoring activities). If signal quality is lower, the use of multiple antennas to handle 1X page monitoring activities may be desired, so device  10  may transition to state  104 , in which two antennas are used for 1X operations (e.g., in monitoring the 1X paging channel for incoming pages). 
     Examples of signal quality measurements that may be made in device  10  to determine whether include bit error rate measurements, signal-to-noise ratio measurements, measurements on the amount of power associated with incoming wireless signals, channel quality measurements based on received signal strength indicator (RSSI) information (RSSI measurements), channel quality measurements based on received signal code power (RSCP) information (RSCP measurements), reference symbol received power (RSRP measurements), channel quality measurements based on signal-to-interference ratio (SINR) and signal-to-noise ratio (SNR) information (SINR and SNR measurements), channel quality measurements based on signal quality data such as Ec/Io or Ec/No data (Ec/Io and Ec/No measurements), etc. 
     With one illustrative arrangement, device  10  will transition from state  100  to state  102  to perform 1X page monitoring operations provided that the 1X signal quality has an RSSI value of greater than threshold TH 1  and will transition from state  100  to state  104  to perform 1X page monitoring operations when the 1X signal quality has an RSSI value of less than TH 1 . Other signal quality measurements and thresholds may be used by control circuitry  42  to determine whether to transition to state  102  or state  104 . The use of RSSI signal quality measurements is merely an example. 
       FIG. 5  is a circuit diagram showing illustrative circuitry that may be used in implementing device  10 . In the illustrative example of  FIG. 5 , device  10  has two antennas—antenna  40 A and  40 B. If desired, device  10  may have additional antennas  40 , as described in connection with  FIG. 3 . Device  10  of  FIG. 5  has radio-frequency transceiver circuitry  60  that includes two receivers (receiver circuitry  61  and receiver circuitry  65 ) and a transmitter (transmitter circuitry  59 ). Baseband processor  58  has protocol stacks  590  such as protocol stack LTE for handling LTE operations and protocol stack 1X for handling 1X operations. Path  46  may be used to couple baseband processor  58  to radiofrequency transceiver circuitry  60 . Radio-frequency transceiver circuitry  60  may be coupled to antennas  40 A and  40 B via radio-frequency front end circuitry  62 . 
     Data from baseband processor  58  may be conveyed to transmitter circuitry  59  via path TX in path  46 . Path  106  may be used to convey data that is to be transmitted to low-pass filter  108 . Transmitter local oscillator  112  may supply a local oscillator output signal to up-converter circuit  110 . Up-converter circuit  110  may upconvert the data signal from low-pass filter  108  and supply a corresponding radio-frequency output signal to amplifier  114 . Amplifier  114  may amplify the radio-frequency signal version of the transmitted data and provide this signal to multiplexer circuit  116  (or other suitable switching circuitry). Multiplexer  116  may supply the data to path LTE TX when the transmitted data is LTE data that is being provided by protocol stack LTE and may supply the data to path 1X TX when the transmitted data is 1X data that is being provided by protocol stack 1X. The state of multiplexer circuit  116  and other circuits in transceiver  60  may be controlled by control signals supplied by baseband processor  58  and/or storage and processing circuitry  28  (e.g., control circuitry  42  of  FIG. 3 ). 
     Radio-frequency front-end circuitry  62  may include filter and switching circuitry for routing incoming and outgoing signals between transceiver circuitry  60  and antennas  40 A and  40 B. For example, radio-frequency frontend circuitry  62  may contain switching circuitry that implements the functions of a crossover (double-pole-double-throw) switch such as switch  122 . The state of switch  122  may be controlled by control signals received on path C 3  from control circuitry  42 . In a first state, switch  122  may route signals between port P 10  and P 11  and may route signals between port P 12  and P 13 . In a second (reversed) state, switch  122  may connect port P 10  to port P 13  and may connect port P 12  to port P 11 . 
     The state of switch  122  may be used to control which receiver and transmitter circuitry is coupled to each antenna. For example, the state of switch  122  may be used to control whether transmitted signals are transmitted through antenna  40 A or antenna  40 B. When it is in its first state, transmitted signals such as LTE signals from path LTE TX or 1X signals from path 1X TX may be transmitted through antenna  40 A. When it is in its second state, transmitted signals such as LTE signals from path LTE TX or 1X signals from path 1X TX may be transmitted through antenna  40 B. 
     Transmitted LTE signals on path LTE TX may be amplified by amplifier  128 . Duplexer filter circuitry  118  may route signals based on their frequency. Incoming radiofrequency signals that are received from port P 4  of switch  120  may be routed to path LTE RX 1 . Transmitted signals from the output of amplifier  128  may be routed to port P 4  of switch  120 . 
     Transmitted 1X signals on path 1X TX from multiplexer  116  may be amplified by amplifier  130 . Duplexer filter circuitry  126  may route signals based on their frequency. Radio-frequency signals that are received from port P 5  of switch  120  may be routed to path 1X RX 1 . Transmitted signals from the output of amplifier  130  may be routed to port P 5  of switch  120 . 
     Radio-frequency switching circuitry in radiofrequency front-end circuitry  62  such as radio-frequency switch  120  may be controlled by control signals from control circuitry  42  that are received on control signal path C 1 . In a first state, radio-frequency switch  120  may couple port P 6  to port P 4 , in a second state, radio-frequency switch  120  may couple port P 6  to port P 5 . When ports P 4  and P 6  are connected, received radio-frequency signals from antenna structures  40  may be routed from port P 6  to port P 4  and transmitted radio-frequency signals may be routed from port P 4  to port P 6  for transmission via antenna structures  40 . When ports P 5  and P 6  are connected, received radio-frequency signals from antenna structures  40  may be routed from port P 6  to port P 5  and transmitted radio-frequency signals may be routed from port P 5  to port P 6  for transmission via antenna structures  40 . 
     Radio-frequency front-end circuitry  62  may also include radio-frequency switching circuitry such as radio-frequency switch  124 . Radio-frequency switch  124  may be configured by control circuitry  42 . In particular, radiofrequency switch  124  may receive control signals from control circuitry  42  on control signal input path C 2 . In response to the control signals received on path C 2 , radio-frequency switch  124  may be placed in a first state in which ports P 7  and P 9  are connected together or in a second state in which a signal path is formed between ports P 8  and P 9 . In its first state (i.e., when configuring switch  124  to receive LTE traffic), received signals from crossover switch  122  may be routed from port P 9  to port P 7  and associated signal path LTE RX 2 . In its second state (i.e., when configuring switch  124  to receive 1X traffic), received signals from crossover switch  122  may be routed from port P 9  to port P 8  and associated signal path 1X RX 2 . 
     Switching circuitry associated with radio-frequency transceiver circuitry  60  may be used in selectively routing signals from the four receive paths (LTE RX 1 , 1X RX 1 , LTE RX 2 , and 1X RX 2 ) in radio-frequency frontend circuitry  62  to receiver circuits  61  and  65 . Multiplexer  138  may, for example, receive incoming radio-frequency signals on paths LTE RX 1  and 1X RX 1  and may route signals from a selected one of these paths to downconverter circuit  136  of receiver  61 . Multiplexer  146  may receive incoming radio-frequency signals on paths LTE RX 2  and 1X RX 2  and may route signals from a selected one of these paths to downconverter circuit  148  of receiver  65 . 
     Local oscillators RX LO may produce local oscillator output signals for receivers  61  and  65 . As shown in  FIG. 5 , for example, local oscillator  140  may produce a radio-frequency output signal at frequency f 2  that is received at port P 1  of switching circuitry  144 . Local oscillator  142  may produce radio-frequency output signals at frequency f 1  that are provided to port P 2  of switch  144  and to downconverter circuit  136  in receiver  61 . The state of switching circuitry  116 ,  138 ,  146 , and  144  may be controlled by control signals received from control circuitry  42  (e.g., baseband processor  58  and/or storage and processing circuitry  28 ). 
     When it is desired to handle LTE signals with receiver  61 , multiplexer  138  may be used to route signals from path LTE RX 1  to downconverter circuitry  136 . After mixing with the local oscillator output from local oscillator  142 , the LTE signal from path LTE RX 1  may be provided to baseband processor  58  via low-pass filter  134 , amplifier  132 , and path RX 1 . Baseband processor  58  may use protocol stack LTE to process the received LTE signals. 
     When it is desired to handle 1X signals with receiver  61 , multiplexer  138  may be used to route signals from path 1X RX 1  to downconverter circuitry  136 . After mixing with the local oscillator output from local oscillator  142 , the 1X signal from path 1X RX 1  may be provided to baseband processor  58  via low-pass filter  134 , amplifier  132 , and path RX 1 . Baseband processor  58  may use protocol stack 1X to process the received 1X signals. 
     When it is desired to handle LTE signals with receiver  65 , multiplexer  146  may be used to route signals from path LTE RX 2  to receiver  65 . When it is desired to handle 1X signals with receiver  65 , multiplexer  146  may be used to route signals from path 1X RX 2  to receiver  65 . 
     The state of switch  144  may be used to determine whether downconverter circuitry  148  is provided with the local oscillator output of local oscillator  140  at frequency f 2  or the local oscillator output of local oscillator  142  at frequency f 1 . Switch  144  may be configured to couple port P 1  to port P 3  when it is desired to provide downconverter  148  with the output of local oscillator  140  at f 2  and may be configured to couple port P 2  to port P 3  when it is desired to provide downconverter  148  with the output of local oscillator  142  at frequency f 1 . After mixing the received 1X or LTE signal from the output of multiplexer  146  with the local oscillator output from local oscillator  142  or the local oscillator output from local oscillator  140 , downconverter circuitry  148  may supply the received 1X or LTE signal to baseband processor  58  via low-pass filter  150 , amplifier  152 , and path RX 2  in path  46 . Baseband processor  58  may use protocol stack LTE to process LTE signals from path LTE RX 2  and protocol stack 1X to process 1X signals from path 1X RX 2 . 
     In operating states in which it is desired to implement receive diversity, switch  144  may be configured to route the output of local oscillator  142  at frequency f 1  to downconverter  148 . Downconverter  136  may simultaneously receive the output of local oscillator  142  at frequency f 1 . In this configuration, receivers  61  and  65  may each receive incoming radio-frequency signals at the same frequency (i.e., frequency f 1 ) and may therefore be used in implementing a two-antenna receive diversity configuration for incoming LTE or 1X signals. 
     When signal strengths (e.g., a received signal strength indicator or other signal quality indicator information) indicate that a single antenna may be used in receiving 1X paging signals, one of the antennas  40 A and  40 B and one of receivers  61  and  65  may be used in receiving LTE signals and the other of antennas  40 A and  40 B and the other of receivers  61  and  65  may be used in receiving 1X signals. When using each receiver in radio-frequency transceiver circuitry  60  to handle a different type of traffic, switch  144  may be configured to route the output of local oscillator  140  at frequency f 2  to downconverter circuitry  148 . Receiver  61  may then be used to receive incoming signals at a first frequency (f 1 ) while receiver  65  is used to simultaneously receive incoming signals at a second frequency f 2  that is different than the first frequency. Depending on the way in which circuitry  60  and circuitry  62  is configured, LTE traffic may be handled by receiver  61  (i.e., LTE traffic from path LTE RX 1 ) while 1X traffic is handled by receiver  65  (i.e., 1X traffic from path 1X RX 2 ) or LTE traffic may be handled by receiver  65  (i.e., LTE traffic from path LTE RX 2 ) while 1X traffic is handled by receiver  61  (i.e., 1X traffic from path 1X RX 1 ). 
       FIG. 6  is a table illustrating how device  10  may operate under various possible combinations of 1X and LTE activity. Some potential combinations of 1X and LTE activities may be handled satisfactorily using circuitry of the type shown in  FIG. 5 , while others may lead to resource conflicts. 
     Consider, as an example, scenarios in which 1X functionality in device  10  is idle (i.e., there is no active 1X voice call being handled by device  10  and device  10  is periodically monitoring the 1X paging channel for incoming calls) and in which received 1X signal strength (as indicated by measured RSSI values or other signal quality factors) is sufficient to allow device  10  to monitor the 1X paging channel using only a single one of the two antennas in device  10 . These scenarios are represented by the first row of the table of  FIG. 6 . As shown in the first row of the table of  FIG. 6 , device performance may be satisfactory when device  10  is operating in an LTE idle state (monitoring for incoming LTE pages) and may be somewhat degraded when device  10  is operating in an LTE active state. 
       FIG. 7  illustrates the type of wireless activity that may occur during use of device  10  to handle LTE idle and 1X idle operations (the left-hand column of the first row of the table of  FIG. 6 ). Because LTE and 1X functions are idle, there is no activity associated with transmitter TX. During most periods of time, the switching circuitry in radio-frequency transceiver  60  and radio-frequency front-end circuitry  62  may be configured to route incoming antenna signals to paths LTE RX 1  and LTE RX 2 . Switch  144  may be configured so that receiver  61  and receiver  65  receive the signals on paths LTE RX 1  and LTE RX 2  using the same local oscillator frequency (f 1 ) (i.e., device  10  may be configured to use both antennas in a receive diversity mode to monitor the LTE paging channel at frequency f 1  for incoming LTE pages). Periods of time in which LTE page monitoring is performed are indicated by the presence of “LTE” page monitoring boxes for both the first receiver (RX 1 ) and second receiver (RX 2 ) in  FIG. 7 . First receiver RX 1  may, for example, correspond to receiver  61  and second receiver RX 2  may, for example, correspond to receiver  65  (or vice versa). 
     The 1X paging cycle may be longer than the LTE paging cycle. As a result, device  10  may periodically need to use the second receiver RX 2  to monitor the 1X paging channel instead of the LTE paging channel. To support this type of operation, the configuration of radio-frequency transceiver circuitry  60  and radio-frequency front-end circuitry  62  may be reconfigured by control circuitry  42 . In particular, switch  144  may be configured to couple port P 1  to port P 3 , so that receiver  65  operates at frequency f 2  while receiver  61  operates at frequency f 1 . Switch  120  may be configured to couple port P 6  to port P 4  to route received signals from one of the antennas to path LTE RX 1 . Switch  124  may be configured to couple port P 9  to port P 8  to route received signals from the other of the antennas to path 1X RX 2 . In the example of  FIG. 5 , switching circuitry is used to route signals. In configurations in which there are only two radio-frequency bands involved, diplexer circuitry may be used to route signals in device  10 . The use of switching circuitry such as the switching circuitry of  FIG. 5  may be preferred when more radio-frequency bands are involved. 
     As shown in  FIG. 7 , 1X pages and LTE pages can be simultaneously monitored by periodically using receiver RX 2  to monitor the 1X paging channel for incoming pages rather than LTE signals. During these time periods (which are illustrated by the boxes labeled “1X” in  FIG. 7 ), one of the antennas in device  10  is used to provide signals to path 1X RX 2  while circuitry  60  monitors the signals on this path (at frequency f 2 ) for incoming 1X pages. At the same time, LTE idle (page monitoring) operations can be performed using the remaining one of the antennas and circuitry RX 1 . Although both antennas and receivers cannot be simultaneously used in monitoring LTE pages during the period in which one of the antennas is being used to monitor 1X pages, this periodic momentary loss of receive diversity for monitoring the LTE paging channel is generally acceptable. Performance is therefore satisfactory, as indicated in the left-hand column of the first row of the table of  FIG. 6 . 
     As illustrated by the entry in the right-hand column of the first row of the table of  FIG. 6 , LTE performance may be degraded somewhat when attempting to operate device  10  in an LTE active state while simultaneously monitoring the 1X channel for pages (i.e., operating the device in a 1X idle mode).  FIG. 8  is a diagram showing how device  10  may operate in this situation. As shown in  FIG. 8 , transmitter TX may be used to transmit LTE data (e.g., using path LTE TX of  FIG. 5  and an associated one of antennas  40 ). 
     In the example of  FIG. 8 , LTE data is initially being received by device  10  using a receive diversity arrangement. For example, at times such as time T 1  of  FIG. 8 , before it is desired to monitor the 1X paging channel for pages, LTE data may be received using both antennas and using corresponding receivers RX 1  and RX 2 . When it is desired to monitor the 1X channel for pages, normal LTE receive diversity operations may be interrupted. In particular, LTE receive diversity operations may be periodically interrupted (for the periods of time labeled “1X WAKE” in  FIG. 8 ) to allow the antenna that is associated with receiver RX 2  to monitor the 1X paging channel for incoming 1X pages. 
     The transition between LTE receive diversity mode and the 1X page monitoring operations of periods “1X WAKE” in  FIG. 8  may take place at times such as time T 2 . Several transmission time intervals before time T 2  (and before each subsequent entry into the 1X WAKE state), device  10  may send a rank indicator of 1 to the network (e.g., base station  21  of  FIG. 2 ). The rank indicator of 1 (or other suitable channel quality indicator) directs the network to transmit data in a single layer only (i.e., in only one of the two simultaneous LTE data paths that are normally transmitted during receive diversity operations). This helps avoid data loss when one of the two LTE data paths becomes unavailable during 1X paging channel monitoring. While the 1X paging channel is being monitored during period 1X WAKE, the remaining incoming LTE data stream can be handled by receiver RX 1  and transmitter TX may be used for transmitting LTE data. Following period 1X WAKE, 1X operations cease (go to sleep) and (during period 1X SLEEP), use of the antenna and receiver that were temporarily used for 1X page monitoring may be returned to use in receiving one of the LTE data streams with device  10  sending a corresponding rank indicator to the LTE network (or other suitable channel quality indicator). 
     With arrangements of the type described in connection with  FIG. 8  (and the right-hand side of the first row of the table of  FIG. 6 ), there is no interruption in LTE service, but there is a degradation in received LTE data throughput due to the temporary loss of the second antenna and receiver for receiving LTE data during periods 1X WAKE. 
     In some situations, received signal quality is poor, so it is not desirable to attempt to receive 1X paging signals using only a single antenna. When device  10  detects that this type of a situation has arisen, 1X page monitoring activities (1X idle mode activities) may be performed using both antennas (i.e., antennas  40 A and  40 B) and corresponding receivers  61  and  65  in transceiver circuitry  60 . As indicated on the left-hand side of the second row of the table of  FIG. 6 , 1X idle operations and LTE idle operations can be performed simultaneously if their paging instances do not collide. As indicated on the right-hand side of the second row of the table of  FIG. 6 , attempts at performing 1X idle operations and LTE active mode operations simultaneously will result in interrupted LTE operations. 
     During operations 1X idle mode and LTE idle mode, switch  120  may be configured to couple port P 6  to port P 5  to route received signals to path 1X RX 1 . Switch  124  may be configured to route received signals to path 1X RX 2 . Switch  144  may be configured to route the signals from local oscillator  142  to port P 3 , so that signals on path RX 2  and on path RX 1  correspond to the same frequency. The frequency may be adjusted depending on whether device  10  is monitoring the LTE paging channel or the 1X paging channel. 
       FIG. 9  is a diagram showing how device  10  may operate when performing simultaneous 1X idle mode and LTE idle mode operations. LTE is in idle mode, so transmitter TX is not being used to transmit LTE data (in this example). During some time periods (labeled “LTE” in  FIG. 9 ), the LTE paging channel may be monitored for LTE pages. Both antennas and receivers  61  and  65  may be used in performing these monitoring operations (i.e., device  10  may be operated in an LTE receive diversity mode). Every 1X paging cycle, transceiver circuitry  60  may be tuned to the 1X paging channel so that 1X pages can be monitored, as indicated by the boxes in  FIG. 9  that are labeled “1X”. Because device has detected that signal quality is relatively low in this example (e.g., because RSSI was measured to be less than a predetermined threshold during the wake period of a preceding paging cycle), device  10  (e.g., control circuitry  42 ) configures wireless circuitry  34  so that 1X pages are monitored using 1X receive diversity (i.e., using both antennas  40  and using both receivers  61  and  65 ). The use of 1X receive diversity improves signal reception, albeit at the expense of periodically resulting in a missed LTE paging cycle. 
     The diagram of  FIG. 10 , which corresponds to attempted simultaneous 1X idle mode and LTE active mode operations (the right-hand side of the second row of the table of  FIG. 6 ) shows how LTE operations are periodically interrupted during periods PINT (i.e., when both antennas are used for monitoring 1X pages in a 1X receive diversity mode). Device  10  may inform the network (base station  21  of  FIG. 2 ) of each expected LTE interruption by sending a rank indicator of 0 (or other suitable channel quality indicator) to the network several transmission time intervals (TTIs) before each 1X page monitoring period directing the network to reduce data transmissions. In response, the network will stop or at least reduce data transmissions to device  10  during periods PINT, minimizing the impact of the LTE service interruptions during periods PINT. 
     Device operation may be satisfactory in situations in which it is desired to simultaneously perform 1X active mode operations with one antenna and LTE idle mode operations, as indicated on the left-hand side of the third row of the table of  FIG. 6 . Device  10  may be configured to handle this scenario by placing switch configuring switch  120  to couple port P 6  to port P 5  to route received signals from a first antenna to path 1X RX and to route transmitted 1X signals from path 1X TX to the first antenna, by configuring switch  124  to couple port P 9  to port P 7  to route received signals from a second antenna to path LTE RX 2 , and by configuring switch  144  to couple port P 1  to port P 3 , so that receivers  65  and  61  operate at frequencies f 2  and f 1 , respectively. When in the 1X non-receive-diversity mode (one antenna), one of the antennas, transmitter  59 , one of the receivers in device  10 , and baseband processor  58  are being used to handle 1X traffic, so there are insufficient resources available to handle the simultaneous transmission and reception of LTE traffic (i.e., LTE active mode operations cannot be supported), as indicated by the entry on the right-hand side of the third row of the table of  FIG. 6 . 
       FIG. 11  is a timing diagram showing the operation of device  10  when transitioning from an LTE active mode to an LTE idle mode and transitioning from a 1X idle mode to 1X active mode. Initially, device  10  is operating in an LTE active and 1X idle state. LTE traffic may be handled using one antenna to transmit LTE data and two antennas (receive diversity) to receive LTE data. Periodically, device  10  may use of one of the two antennas (e.g., the antenna associated with receiver RX 2 ) to monitor the 1X paging channel for incoming 1X pages (see, e.g., the 1X wake interval starting at time TT in the  FIG. 11  example). Several transmission time intervals before time TT, device  10  may send a rank indicator of 1 (or other channel quality indicator) to the network to direct the network to reduce the transmission of data (i.e., to transmit data using only one LTE data stream), thereby minimizing disruption to LTE operations during the temporary use of the RX 2  receiver and associated antenna to monitor 1X pages. 
     When device  10  receives an incoming 1X page, device  10  may transition to 1X active mode, as shown in  FIG. 11 . Because signal quality is sufficient (in this example), only a single antenna need be used for handling 1X data reception activities. Accordingly, the remaining antenna can be used to handle LTE idle mode operations (monitoring the LTE paging channel for incoming pages). 
     As shown in the fourth row of the table of  FIG. 6 , LTE operations will be interrupted when operating in a 1X active mode in environments in which the signal strength is insufficient to support operation with only a single antenna. When operating in a 1X receive diversity (two antenna) active mode, switching circuitry  120  may be configured so that port P 6  is coupled to port P 5  (so that received antenna signals from a first of the two antennas are routed to path 1X RX 1 ), switching circuitry  124  may be configured so that port P 9  is coupled to port P 8  (so that received antenna signals from a second of the two antennas are routed to path 1X RX 2 ), and switching circuitry  144  may be configured so that port P 2  is coupled to port P 3  (i.e., so that receivers  61  and  65  operate at the same frequency). Transmitted 1X signals may be handled using path 1X TX. The use of both antennas to support 1X data reception active mode operations and the use of one of the antennas to support 1X data transmission operations will interrupt LTE operations regardless of whether it is desired to operate in an LTE idle mode (the left-hand side of the fourth row of the  FIG. 6  table) or in LTE active mode (the right-hand side of the fourth row of the  FIG. 6  table). 
       FIG. 12  is a timing diagram illustrating how the use of both antennas in device to support 1X active mode operations may interrupt LTE activity. Initially, (e.g., at times before time TW 1 ), both antennas may be used for LTE operations (e.g., LTE active mode operations or LTE idle mode operations). Periodically (e.g., at times such as time TW 1  and time TW 2  in the  FIG. 12  example), one of the antennas (e.g., the antenna coupled to receiver RX 2 ) may be used to monitor the 1X paging channel. 
     To minimize disruption to LTE operations, device may send a rank indicator of 1 or other such channel quality indicator to the network several transmission time intervals before switching use of one of the antennas from LTE activities to 1X page monitoring (i.e., several transmission time intervals before 1X page monitoring times such as times TW 1  and TW 2 ). In response, the network can reduce LTE data transmissions (e.g., by reducing transmissions from two active LTE data streams to one LTE data stream or taking other suitable action), thereby minimizing disruption to LTE operations. 
     In the  FIG. 12  example, an incoming 1X page is detected at time TW 3 . As a result, device  10  enters 1X active mode at time TW 3  and uses both antennas (i.e., the antenna coupled to receiver RX 1  and the antenna coupled to receiver RX 2 ) in handling a 1X call. Both antennas are being used to handle 1X activities, so LTE operations (active mode or idle mode) are interrupted. 
     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: 20150625
Publication Date: 20161115
Grant Date: 20161115
Priority Date: 20110418
Inventors: MUJTABA SYED AON
ZHAO WEN
WANG XIAOWEN
MAJJIGI VINAY
MAHE ISABEL G.
Assignee: APPLE INC
CPC Classifications: [{"code": "H04W88/06", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04B7/0802", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04W88/10", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04W24/00", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04W68/00", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04W24/08", "inventive": true, "first": true, "tree": "[]"}, {"code": "H04B7/0602", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04B7/0602", "inventive": true, "first": true, "tree": "[]"}, {"code": "H04W88/06", "inventive": true, "first": true, "tree": "[]"}, {"code": "H04W68/00", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04W88/06", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04W88/06", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04B1/26", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04W68/00", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04W24/00", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04B7/0802", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04W88/10", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04W24/00", "inventive": true, "first": true, "tree": "[]"}, {"code": "H04B7/0602", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04L1/20", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04B7/0802", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04B1/26", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04W88/06", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04B17/309", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04B7/0802", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04W24/00", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04W68/00", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04W88/10", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04W24/08", "inventive": true, "first": true, "tree": "[]"}, {"code": "H04B7/0602", "inventive": true, "first": false, "tree": "[]"}]
Family ID: 46044397