PATENT DOCUMENT

Publication Number: US-9699784-B2
Application Number: US-201514724734-A
Country: US
Kind Code: B2

Title: Systems and methods for establishing wireless communications between wireless circuitry and multiple base stations

Abstract:
An electronic device has wireless communications circuitry. The wireless circuitry may transmit and receive wireless signals over a network having first and second wireless base stations. The first base station may establish a primary wireless connection with the device using selected connection settings and may transmit the selected connection settings to the second base station. The second base station may copy the received connection settings to establish a secondary wireless connection with the device while the primary connection is simultaneously maintained. After the primary and secondary connections have been established, the first and second base stations may transmit data streams to the electronic device over different frequency bands in a carrier aggregation link. By using the second base station to copy the received connection settings that were used by the first base station to establish the primary connection, the connection time for establishing the carrier aggregation link may be improved.

Claims:
What is claimed is: 
     
       1. A method of operating a wireless system having first and second base stations for wirelessly communicating with an electronic device, the method comprising:
 with the first base station, establishing a first wireless connection between the first base station and the electronic device using a set of wireless connection settings; 
 with the first base station, transmitting the set of wireless connection settings to the second base station, wherein the transmitted set of wireless connection settings comprises a selected resource block allocation and establishing the first wireless connection comprises establishing the first wireless connection between the first base station and the electronic device using the selected resource block allocation; and 
 with the second base station, establishing a second wireless connection between the second base station and the electronic device based on the set of wireless connection settings while the first base station simultaneously maintains the first wireless connection with the electronic device, wherein establishing the second wireless connection comprises establishing the second wireless connection between the second base station and the electronic device using the selected resource block allocation of the wireless connection settings received from the first base station. 
 
     
     
       2. The method defined in  claim 1 , further comprising:
 with the first and second base stations, simultaneously transmitting first and second data streams to the electronic device over respective first and second frequency bands, wherein the second frequency band is different from the first frequency band. 
 
     
     
       3. The method defined in  claim 2 , wherein the first base station comprises storage circuitry, the method further comprising:
 with the first base station, storing neighboring base station information on the storage circuitry that identifies the second base station and the second frequency band; and 
 with the first base station, transmitting the stored neighboring base station information to the electronic device over the first frequency band. 
 
     
     
       4. The method defined in  claim 2 , further comprising:
 with the first base station, receiving device identification information from the electronic device over the first frequency band and transmitting the received device identification information to the second base station. 
 
     
     
       5. The method defined in  claim 4 , further comprising:
 with the second base station, receiving a request to establish the second wireless connection from the electronic device over the second frequency band; and 
 with the second base station, retrieving additional device identification information from the electronic device over the second frequency band in response to receiving the request to establish the second wireless connection. 
 
     
     
       6. The method defined in  claim 5 , further comprising:
 with the second base station, determining whether to establish the second wireless connection between the second base station and the electronic device by comparing the device identification information received from the first base station to the additional device identification information received from the electronic device; and 
 with the second base station, establishing the second wireless connection in response to determining that the device identification information received form the first base station matches the additional device identification information received from the electronic device. 
 
     
     
       7. The method defined in  claim 2 , wherein establishing the second wireless connection between the second base station and the electronic device comprises:
 establishing the second wireless connection with the electronic device without dropping the first wireless connection between the first base station and the electronic device. 
 
     
     
       8. The method defined in  claim 2 , wherein the selected resource block allocation comprises a Long-Term-Evolution (LTE) protocol resource block allocation. 
     
     
       9. The method defined in  claim 2 , wherein establishing the second wireless connection between the second base station and the electronic device based on the received set of wireless connection settings comprises:
 copying at least one of the received wireless connection settings used by the first base station to establish the first wireless connection at the second base station; and 
 transmitting radio-frequency downlink signals to the electronic device over the second frequency band using the copied wireless connection settings. 
 
     
     
       10. The method defined in  claim 9 , wherein the copied wireless connection settings include at least one of: a downlink power level setting, a modulation scheme setting, and a bandwidth setting. 
     
     
       11. The method defined in  claim 2 , wherein simultaneously transmitting the first and second data streams to the electronic device over the respective first and second frequency bands comprises transmitting the first and second data streams to the electronic device over Long-Term-Evolution band 17 and Long-Term-Evolution band 4, respectively. 
     
     
       12. The method defined in  claim 1 , wherein establishing the second wireless connection between the second base station and the electronic device based on the received set of wireless connection settings comprises establishing the second wireless connection using a subset of the set of wireless connection settings. 
     
     
       13. The method defined in  claim 1 , wherein establishing the second wireless connection between the second base station and the electronic device based on the received set of wireless connection settings comprises establishing the second wireless connection using all of the wireless connection settings in the received set of wireless connection settings. 
     
     
       14. The method defined in  claim 1 , further comprising:
 with the first base station, transmitting the set of wireless connection settings to a third base station; and 
 with the third base station, establishing a third wireless connection between the third base station and the electronic device based on the set of wireless connection settings while the first base station simultaneously maintains the first wireless connection and the second base station simultaneously maintains the second wireless connection with the electronic device. 
 
     
     
       15. A method of receiving radio-frequency transmissions under a carrier aggregation scheme using wireless communications circuitry, the method comprising:
 with the wireless communications circuitry, establishing a first wireless connection with a first wireless base station using selected connection settings; 
 with the wireless communications circuitry, receiving neighboring base station information from the first base station that identifies a second base station, wherein the neighboring base station information comprises a first wireless coverage area associated with the first base station and a second wireless coverage area associated with the second base station; 
 with the wireless communications circuitry, determining whether the wireless communications circuitry is located within an overlap region between the first wireless coverage area and the second wireless coverage area; and 
 in response to determining that the wireless communications circuitry is located in the overlap region between the first wireless coverage area and the second wireless coverage area, with the wireless communications circuitry, transmitting a request to establish a second wireless connection with the second wireless base station based on the received neighboring base station information while maintaining the first connection with the first base station. 
 
     
     
       16. The method defined in  claim 15 , further comprising:
 with the wireless communications circuitry, establishing the second wireless connection with the second wireless base station using at least some of the selected connection settings without dropping the first connection with the first base station. 
 
     
     
       17. The method defined in  claim 16 , further comprising:
 with the wireless communications circuitry, receiving a first data stream from the first base station over the first wireless connection in a first frequency band and simultaneously receiving a second data stream from the second base station over the second wireless connection in a second frequency band that is different from the first frequency band; and 
 with baseband circuitry in the wireless communications circuitry, combining the first and second data streams into a single data stream. 
 
     
     
       18. The method defined in  claim 17 , wherein receiving the neighboring base station information from the first base station comprises receiving the neighboring base station information over the first frequency band, wherein the received neighboring base station information identifies that the second frequency band is in use by the second base station, and wherein transmitting the request to establish the second wireless connection based on the received neighboring base station information comprises transmitting the request to the second base station over the second frequency band. 
     
     
       19. A wireless communications system for communicating with wireless communications circuitry, comprising:
 a first base station, wherein the first base station is configured to establish a primary wireless connection with the wireless communications circuitry in a first frequency band using selected connection settings, wherein the selected connection settings comprise a selected resource block allocation; and 
 a second base station, wherein the second base station is configured to receive the selected connection settings from the first base station and to establish a secondary wireless connection with the wireless communications circuitry in a second frequency band that is different from the first frequency band using the selected resource block allocation of the selected connection settings received from the first base station while the first base station maintains the primary wireless connection. 
 
     
     
       20. The wireless communications system defined in  claim 19 , wherein the selected connection settings comprise a selected modulation scheme setting and the selected resource block allocation comprises a Long-Term-Evolution resource block allocation. 
     
     
       21. The wireless communications system defined in  claim 20 , wherein the first base station is configured to transmit a first portion of a data signal to the wireless communications circuitry over the first frequency band and the second base station is configured to simultaneously transmit a second portion of the data signal to the wireless communications circuitry over the second frequency band after the primary and secondary wireless connections have been established.

Description:
This application claims the benefit of provisional patent application No. 62/012,227 filed Jun. 13, 2014, 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 that simultaneously receives radio-frequency transmissions in different frequency bands. 
     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. Global Positioning System (GPS) receiver circuitry and other satellite receiver circuitry may be used to receive satellite navigation signals. Local wireless links may be used to support local area network communications such as IEEE 802.11 communications at 2.4 GHz and 5 GHz. Local links may also be used to handle Bluetooth® communications at 2.4 GHz. 
     It is often desirable for a device to support multiple bands. For example, users of a cellular telephone may desire to communicate with cellular base stations using one or more different cellular telephone bands and may desire to communicate with local area network equipment using wireless local area network (WLAN) communications bands. 
     In conventional electronic devices with wireless communications circuitry, the wireless communications circuitry is typically configured to convey radio-frequency signals over a selected communications band with a single wireless base station. The wireless communications circuitry includes filtering circuitry and switching circuitry for transmitting and receiving wireless signals in the selected communications band. The filtering and switching circuitry is adjustable to switch to a different band for transmitting and receiving wireless signals. Using a single communications band for transmitting and receiving wireless signals often limits the bandwidth and data throughput that is obtainable by the wireless communications circuitry. Using a single wireless base station to perform wireless communications operations can limit the data throughput that is obtainable by the wireless communications circuitry when the associated electronic device moves to locations at greater distances from the base station. 
     It would therefore be desirable to be able provide systems and methods for transmitting and receiving wireless signals over multiple communications bands between a wireless device and multiple wireless base stations. 
     SUMMARY 
     An electronic device may be provided with wireless communications circuitry. The wireless communications circuitry may include radio-frequency transceiver circuitry for handling wireless communications. The radio-frequency transceiver may have multiple transmitters and multiple receivers. Antenna structures may be used to transmit and receive signals. 
     The antenna structures may be coupled to transmitters and receivers in the radio-frequency transceiver circuitry. Switching circuitry such as first and second radio-frequency switch stages may be used to support multiple communications bands of interest. The first and second radio-frequency switch stages may be configured in real time to switch desired frequencies into use. The wireless communications circuitry may handle radio-frequency signals that are simultaneously received and/or transmitted in multiple frequency bands. For example, the wireless communications circuitry may handle data streams that are simultaneously received from multiple wireless base stations (e.g., using a carrier aggregation scheme), allowing for the wireless communications circuitry to have improved data throughput relative to devices that receive signals only over a single frequency band. 
     The electronic device may transmit and receive wireless signals with a wireless system having multiple wireless base stations. The wireless base stations and the electronic device may handle radio-frequency signals using a Long-Term-Evolution (LTE) protocol. The first wireless base station may establish a first wireless connection between the first wireless base station and the electronic device using a set of wireless connection settings (e.g., using selected power levels, a selected modulation scheme, a selected LTE resource block allocation, a selected bandwidth, throughput, etc.). The first wireless base station may transmit the set of wireless connection settings used for establishing the first wireless connection to the second wireless base station. 
     The second wireless base station may establishing a second wireless connection between the second base station and the electronic device using some or all of the wireless connection settings included in the set of wireless connection settings received from the first wireless base station. For example, the second base station may copy (clone) one or more of the received wireless connection settings for use in establishing the second wireless connection. The second wireless connection may be established while the first base station simultaneously maintains the first wireless connection with the electronic device (e.g., without dropping the first wireless connection). After the first and second connections have been established, the first and second wireless base stations may simultaneously transmit first and second data streams to the electronic device over respective frequency bands (e.g., over respective LTE bands using a carrier aggregation scheme or link). By copying wireless connection settings that were successfully used by the first base station to establish the first wireless connection, the carrier aggregation link (connection) between the electronic device and the first and second base stations over the first and second frequency bands may require less time to set up than systems that cycle through possible connection settings for each base station (e.g., connection time required to establish the carrier aggregation link between the electronic device and multiple base stations may be improved). 
     The first base station may include storage circuitry and may store neighboring base station information and/or device information associated with the electronic device on the storage circuitry. The neighboring base station information may identify the second wireless base station and the frequency band in use by the second wireless base station. The first base station may transmit some or all of the neighboring base station information to the electronic device over the first frequency band. The electronic device may identify a first wireless coverage area associated with the first base station and may identify a second wireless coverage area associated with the second base station in the received neighboring base station information. The electronic device may determine whether the electronic device is located within an overlap region between the first two coverage regions and may transmit a request to establish the second connection over the second frequency band in response to determining that the electronic device is within the overlap region. The first base station may receive device identification information from the electronic device over the first frequency band and may transmit the information to the second base station. 
     The second base station may receive a request to establish the second wireless connection over the second frequency band and may retrieve additional device identification information from the electronic device over the second frequency band in response to receiving the request to establish the second wireless connection. The second base station may determine whether to establish the second wireless connection between the second base station and the electronic device by comparing the device identification information received from the first base station to the additional device identification information received from the electronic device. For example, the second base station may establish the second wireless connection in response to determining that the device identification information received form the first base station matches the additional device identification information received from the electronic device (e.g., to ensure that the second wireless connection is not established with an independent wireless device that is not attempting to connect to both of the first and second base stations). 
     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 diagram showing how radio-frequency transceiver circuitry may be coupled to one or more antennas within an electronic device of the type shown in  FIG. 1  in accordance with an embodiment of the present invention. 
         FIG. 3  is a diagram of illustrative wireless circuitry including multiple antennas and circuitry for controlling use of the antennas in real time to simultaneously convey radio-frequency signals in multiple frequency bands to multiple wireless base stations in accordance with an embodiment of the present invention. 
         FIG. 4  is a diagram showing how wireless communications circuitry may transmit radio-frequency signals using a Long Term Evolution (LTE) protocol in accordance with an embodiment of the present invention. 
         FIG. 5  is a diagram showing how wireless communications circuitry may communicate using one or more resource blocks of a radio-frequency channel in an LTE frequency band in accordance with an embodiment of the present invention. 
         FIG. 6  is a circuit diagram of illustrative wireless communications circuitry that may be configured to simultaneously transmit and/or receive radio-frequency transmissions in different frequency bands with multiple wireless base stations in accordance with an embodiment of the present invention. 
         FIG. 7  is a graph of illustrative frequency bands that may be simultaneously received with wireless communications circuitry such as the wireless communications circuitry of  FIG. 6  in accordance with an embodiment of the present invention. 
         FIG. 8  is a diagram showing how a wireless device may simultaneously communicate with multiple wireless base stations at different geographic locations using different frequency bands in accordance with an embodiment of the present invention. 
         FIG. 9  is a flow chart of illustrative steps that may be performed with wireless network and a wireless device to simultaneously receive radio-frequency transmissions in different frequency bands from multiple wireless base stations in accordance with an embodiment of the present invention. 
         FIG. 10  is a flow chart of illustrative steps that may be performed by a wireless network to establish simultaneous wireless connections between a wireless device and multiple wireless base stations in different frequency bands by conveying device connection settings between the wireless base stations in accordance with an embodiment of the present invention. 
         FIG. 11  is a flow chart of illustrative steps that may be performed by a wireless device to establish simultaneous wireless connections with multiple wireless base stations for sending and receiving wireless signals with the base stations in different frequency bands in accordance with an embodiment of the present invention. 
         FIG. 12  is an illustrative diagram of connection settings that may be used to successfully establish a wireless connection between a wireless device and a first wireless base station and that may be cloned at a second wireless base station to establish a second simultaneous wireless connection between the wireless device and the second wireless base station 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 long-range wireless communications such as communications in cellular telephone bands. 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. Long-range signals such as signals associated with satellite navigation bands may be received by the wireless communications circuitry of device  10 . For example, device  10  may use wireless circuitry to receive signals in the 1575 MHz band associated with Global Positioning System (GPS) communications. Short-range wireless communications may also be supported by the wireless circuitry of device  10 . For example, device  10  may include wireless circuitry for handling local area network links such as WiFi® links at 2.4 GHz and 5 GHz, Bluetooth® links at 2.4 GHz, etc. 
     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  41 . 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  41  for receiving GPS signals at 1575 MHz or for handling other satellite positioning data such as Global Navigation Satellite System (GLONASS) 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. 
     Antenna diversity schemes may be implemented in which multiple redundant antennas are used in handling communications for a particular band or bands. In an antenna diversity scheme, storage and processing circuitry  28  may select which antenna to use in real time based on signal strength measurements or other data. In multiple-input-multiple-output (MIMO) schemes, multiple antennas may be used to transmit and receive multiple data streams, thereby enhancing data throughput. 
     Illustrative locations in which antennas  40  may be formed in device  10  are shown in  FIG. 2 . As shown in  FIG. 2 , electronic device  10  may have a housing such as housing  12 . Housing  12  may include plastic walls, metal housing structures, structures formed from carbon-fiber materials or other composites, glass, ceramics, or other suitable materials. Housing  12  may be formed using a single piece of material (e.g., using a unibody configuration) or may be formed from a frame, housing walls, and other individual parts that are assembled to form a completed housing structure. The components of device  10  that are shown in  FIG. 1  may be mounted within housing  12 . Antenna structures  40  may be mounted within housing  12  and may, if desired, be formed using parts of housing  12  (e.g., parts of housing  12  may be used in forming antenna resonating element structures for antennas  40 , ground plane structures for antennas  40 , etc.). For example, housing  12  may include metal housing sidewalls, peripheral conductive members such as band-shaped members (with or without dielectric gaps) that extend along the periphery of device  10  (e.g., along exterior surfaces of device  10 ), conductive bezels, and other conductive structures that may be used in forming antenna structures  40 . 
     As shown in  FIG. 2 , antenna structures  40  may be coupled to transceiver circuitry  90  by paths such as paths  45 . Paths  45  may include transmission line structures such as coaxial cables, microstrip transmission lines, stripline transmission lines, etc. Paths  45  may also radio-frequency front end circuitry such as impedance matching circuitry, filter circuitry, and switching circuitry. Impedance matching circuitry may be used to ensure that antennas  40  are efficiently coupled to transceiver circuitry  90  in communications bands of interest. Filter circuitry may be used to implement frequency-based multiplexing circuits such as diplexers, duplexers, and triplexers. Switching circuitry may be used to selectively couple antennas  40  to desired ports of transceiver circuitry  90 . For example, in one operating mode a switch may be configured to route one of paths  45  to a given antenna and in another operating mode the switch may be configured to route a different one of paths  45  to the given antenna. The use of switching circuitry between transceiver circuitry  90  and antennas  40  allows device  10  to support multiple communications bands of interest with a limited number of antennas. 
     In a device such as a cellular telephone that has an elongated rectangular outline, it may be desirable to place antennas  40  at one or both ends of the device. As shown in  FIG. 2 , for example, some of antennas  40  may be placed in upper end region  42  of housing  12  and some of antennas  40  may be placed in lower end region  44  of housing  12 . The antenna structures in device  10  may include a single antenna in region  42 , a single antenna in region  44 , multiple antennas in region  42 , multiple antennas in region  44 , or may include one or more antennas located elsewhere in housing  12 . 
     Antenna structures  40  may be formed within some or all of regions such as regions  42  and  44 . For example, an antenna such as antenna  40 T- 1  may be located within region  42 - 1  or an antenna such as antenna  40 T- 2  may be formed that fills some or all of region  42 - 1 . An antenna such as antenna  40 B- 1  may fill some or all of region  44 - 2  or an antenna such as antenna  40 B- 2  may be formed in region  44 - 1 . These types of arrangements need not be mutually exclusive. For example, region  44  may contain a first antenna such as antenna  40 B- 1  and a second antenna such as antenna  40 B- 2 . 
     Transceiver circuitry  90  may contain transmitters such as transmitters  48  and receivers such as receivers  50 . Transmitters  48  and receivers  50  may be implemented using one or more integrated circuits (e.g., cellular telephone communications circuits, wireless local area network communications circuits, circuits for Bluetooth® communications, circuits for receiving satellite navigation system signals, power amplifier circuits for increasing transmitted signal power, low noise amplifier circuits for increasing signal power in received signals, other suitable wireless communications circuits, and combinations of these circuits). 
     Device  10  may be a relatively large device (e.g. the lateral dimensions of housing  12  may be tens of centimeters or larger) or may be a relatively compact device such as a handheld device that has a longitudinal dimension along the main axis of housing  12  that is 15 cm or less, 10 cm or less, or 5 cm or less, and that has smaller transverse dimensions. In miniature devices such as wrist-mounted, pendant, and clip-mounted devices, the dimensions of housing  12  may be 10 cm or less or 5 cm or less (as examples). 
     Device  10  can be controlled by control circuitry that is configured to store and execute control code for implementing control algorithms (e.g., antenna diversity control algorithms and other wireless control algorithms). As shown in  FIG. 3 , control circuitry  52  may include storage and processing circuitry  28  (e.g., a microprocessor, memory circuits, etc.) and may include baseband processor  54 . Baseband processor  54  may form part of wireless circuitry  34  and may include memory and processing circuits (i.e., baseband processor  54  may be considered to form part of the storage and processing circuitry of device  10 ). 
     Baseband processor  54  may provide data to storage and processing circuitry  28  via path  56 . The data on path  56  may include raw data and processed data associated with wireless (antenna) performance metrics such as received power, transmitted power, frame error rate, bit error rate, signal-to-noise ratio, information on whether responses 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 re-transmissions 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, and other information that is reflective of the performance of wireless circuitry  34 . This information may be gathered for multiple antennas in real time using multiple active transceiver ports or using a time-division multiplexing scheme in which an alternate antenna(s) is momentarily used to evaluate its performance. Information on antenna performance metrics that has been gathered can be processed by storage and processing circuitry  28  and/or processor  54 . Performance metric information may, for example, be used by communications circuitry  34  to determine whether a successful connection with external wireless communication equipment has been established. If desired, storage and processing circuitry  28  may control baseband processor  54  and transceiver circuitry  90  by providing control signals over paths  56  and  58 . As an example, storage and processing circuitry  28  may issue control commands to baseband processor  54  and/or transceiver circuitry  90  in response determining that predetermined performance criteria have been satisfied. 
     Wireless circuitry  34  may include radio-frequency front end circuitry  60  interposed on paths  45  between transceiver circuitry  90  and antennas  40 . Power amplifier circuitry such as amplifier  72  may be interposed on paths  45  between transmitters  48  and front end circuitry  60  for amplifying signals transmitted by transmitters  48 . Low noise amplifier circuitry such as amplifier  74  may be interposed on paths  45  between receivers  50  and front end circuitry  60  for amplifying signals received over antennas  40 . Control circuitry  52  may provide control signals to amplifiers  72  and  74  over path  76  to adjust amplifiers  72  and  74  (e.g., to adjust the gain provided by amplifiers  72  and  74 ). For example, control circuitry  52  may provide a desired bias voltage to power amplifiers  72  so that signals transmitted by transmitters  48  are provided at a desired uplink power level for transmission over antennas  40 . Radio-frequency front end circuitry  60  may include switches such as switching circuitry  68 , impedance matching circuitry such as matching circuitry  70 , filtering circuitry such as diplexer circuitry  64  and duplexer circuitry  66 , radio-frequency coupling circuitry, connector circuitry, and any other desired radio-frequency circuitry. 
     Baseband processor  54  may receive digital data that is to be transmitted using wireless circuitry  34  and may use path  62  and transceiver circuitry  90  (e.g., one or more transmitters  48  in transceiver circuitry  90 ) to transmit corresponding radio-frequency signals on one or more paths  45 . Radio-frequency front end  60  may be used to transmit the radio-frequency signals. Incoming radio-frequency signals that are received by antennas  40  may be provided to baseband processor  54  via radio-frequency front end  60 , paths such as one or more paths  45 , amplifier circuitry  74 , receiver circuitry in radio-frequency transceiver  90  such as one or more receivers  50 , and paths such as path  62 . If desired, individual antennas  40  (e.g., a first antenna  40 - 1 , a second antenna  40 - 2 , etc.) may provide received radio-frequency signals to a single corresponding receiver  50 , individual antennas  40  may provide received radio-frequency signals to different receivers  50  (e.g., different receivers for handling received signals at different frequencies or in different frequency bands), multiple antennas  40  may provide received radio-frequency signals to a single receiver  50 , etc. 
     Due to the close proximity of the antennas within device  10  in at least some device configurations, there may be a potential for interference between communication bands. This potential for interference may be exacerbated by the presence of the circuitry in paths  45 , which may generate undesirable frequency harmonics. For example, switches in paths  45  may have non-linear properties that lead to the generation of second harmonics, third harmonics, and higher-order harmonics when passing radio-frequency signals. 
     Device  10  can reduce or undesirable interference between generated harmonics and signals received by antennas  40  by including filtering circuitry in paths  45  that blocks harmonics associated with transmitted signals before they reach antennas  40 . Because the magnitude of transmitted harmonics is substantially reduced, the magnitude of any harmonics that are received by other antenna and receiver circuitry in device  10  is substantially reduced. By effectively preventing harmonics from being transmitted, the potential for signal interference is eliminated and satisfactory device operation is ensured. 
     If desired, antennas such as antennas  40  may receive wireless transmissions from one or more cellular base stations such as base stations  80  (e.g., a first base station  80 - 1 , a second base station  80 - 2 , etc.) and may transmit wireless signals to one or more of base stations  80 . For example, one or more of antennas  40  may communicate with base station  80 - 1  over communications link  82 , may communicate with base station  80 - 2  over communications link  84 , or may simultaneously communicate with base stations  80 - 1  and  80 - 2  over both communications links  82  and  84 . 
     Duplexer circuitry  66 , diplexer circuitry  64 , and switching circuitry  68  in front end  60  may selectively route signals received from base stations  80  and may selectively route signals transmitted to base stations  80  based on the frequency of the radio-frequency signals. For example, diplexer circuitry  64 , duplexer circuitry  66 , and switching circuitry  68  may be configured by control signals received from control circuitry  52  over path  76  to route transmit frequency signals and receive frequency signals in different uplink and downlink communications bands between one or more antennas  40  and corresponding transmitters  48  and receivers  50 . Switching circuitry  68  may include multiple switches (e.g., multiple stages of switches) each of which is associated with a respective frequency range. The states of switches within switching circuitry  68  (i.e., which switch terminals are connected to each other in the switching circuitry) may be controlled by using control circuitry  52  using control signals received over path  76 . Switches in switching circuitry  68  preferably have a sufficient number of terminals (switch ports) to allow all desired transmitters  48  and receivers  50  to be coupled to antennas  40 . Switching circuitry  68  may include, for example, SP4T (single pole four throw), SP5T (single pole five throw) switches, or any other desired switches. Switches with more terminals or fewer terminals may be used if desired. 
     Base stations  80  may include wireless communications circuitry and one or more antennas  98  for communicating with device  10 . Each base station  80  may include storage and processing circuitry such as circuitry  92 . Storage and processing circuitry  92  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  92  may be used to control the operation of base stations  80 . This processing circuitry may be based on one or more microprocessors, microcontrollers, digital signal processors, application specific integrated circuits, etc. For example, circuitry  92  may generate and transmit downlink signals for transmission to device  10  over antennas  98 . In general, radio-frequency signals conveyed from transmitters  48  on device  10  to base stations  80  may sometimes be referred to as uplink signals, whereas radio-frequency signals conveyed from base stations  80  to receivers  50  on device  10  may sometimes be referred to as downlink signals. 
     If desired, storage circuitry  92  may be used to store device information  94 . Device information  94  may include information about device  10  such as device identification information and connection settings associated with communications links  82  and/or  84  with which base stations  80  are in communication with device  10  (e.g., device settings used by device  10  to send and receive signals with base stations  80 ). If desired, storage circuitry  92  may store neighboring base station information  96 . Base station information  96  may include information about other base stations  80  that are geographically nearby a given base station. For example, a first base station  80 - 1  may store information  96  identifying that base station  80 - 2  or other base stations are geographically near to base station  80 - 1 . In general, neighboring base stations identified by information  96  may be any base station within a predetermined distance of a particular base station or may be other base stations having wireless coverage that overlaps with the wireless coverage of a particular base station. If desired, information  96  may include frequency information associated with the neighboring base stations. For example, information  96  may identify one or more communications frequencies (e.g., communications bands) that are being used by each neighboring base station  80 . 
     Wireless signals received by device  10  from base stations  80  may be provided to diplexer circuitry  64  (e.g., to one or more diplexers within circuitry  64 ). Diplexer circuitry  64  may include circuitry that routes signals according to frequency. For example, diplexer circuitry  64  may have a low pass filter and a high pass filter that divide received wireless transmissions into low frequencies and high frequencies, respectively, while minimizing signal loss (e.g., while minimizing insertion loss). During signal transmission, low band signals and high band signals received from transmitters  48  may be combined by diplexer circuitry  64  and the resulting combined signals may be output to antennas  40 . 
     Duplexer circuitry  66  may be formed from filter circuitry that provides high isolation between transmitted and received signals. For example, the radio-frequency signals transmitted by transmitters  48  may be much larger than the radio-frequency signals received by receivers  50  (e.g., tens of dBm larger). Duplexers  66  may help prevent the relatively large signals transmitted by the transmitters  50  from being received by receivers  48 , thereby providing high isolation between the transmitters and the receivers. In other words, duplexer circuitry  66  may provide high out-of-band attenuation for transceiver circuitry  90 . Control circuitry  52  may configure switching circuitry  68  to route transmit and receive signals between corresponding antennas  40  and the desired transmitter and receiver circuits. 
     Radio-frequency signals transmitted and received by the wireless communications circuitry  34  may be generated and operated on in accordance with the LTE communications protocol. The LTE communications protocol uses an Orthogonal Frequency-Division Multiplexing (OFDM) digital modulation scheme. The OFDM scheme is a type of frequency-division multiplexing scheme in which a large number of closely-spaced orthogonal subcarriers are used to carry data. Different variants of the OFDM scheme may be used for uplink signal transmission and downlink signal transmission, respectively. For example, downlink signals may be modulated using an Orthogonal Frequency Multiple Access (OFDMA) scheme and uplink signals may be modulated using a Single-Carrier Frequency Division Multiple Access (SC-FDMA) scheme. The closely-spaced orthogonal subcarriers may sometimes be referred to as frequency subcarriers, because each subcarrier may correspond to a range of frequencies (e.g., a range of frequencies having a bandwidth of 15 kHz). The data in each subcarrier may be modulated using respective digital modulation schemes such as quadrature phase shift keying (QPSK) and quadrature amplitude modulation (e.g., 16-QAM and 64-QAM). Base station such as base stations  80  may modulate downlink signals transmitted to device  10  using a selected modulation scheme and wireless circuitry  34  on device  10  may modulate uplink signals transmitted to base stations  10  using a selected modulation scheme. 
     As shown in  FIG. 4 , a designated user device may be given permission to transmit uplink signals during each time slot. For example, a first user device UE 1  (e.g., a device such as device  10  of  FIGS. 1-3 ) may transmit uplink signals to a corresponding base station  80  during a first time period, a second user device UE 2  may transmit uplink signals to the base station during a second time period, a third user device UE 3  may transmit uplink signals to the base station during a third time period, etc. In another suitable arrangement, a base station  80  may broadcast downlink signals intended for more than one user device during a given time slot (e.g., LTE may implement Orthogonal Frequency-Division Multiple Access for downlink transmission). 
     A wireless electronic device such as device  10  may simultaneously transmit uplink signals in multiple resource blocks  300  during each time slot. Each time slot is partitioned in time into a number of OFDM symbols. A resource block may serve as a basic scheduling unit that is defined as a set of consecutive OFDM symbols in the time domain and a set of consecutive frequency subcarriers in the frequency domain. For example, a resource block such as resource block  300  may be defined as 7 consecutive OFDM symbols in the time domain and 12 consecutive frequency subcarriers in the frequency domain. The set of consecutive OFDM symbols used to define a resource block may depend on a parameter such as a normal or extended Cyclic Prefix. Each resource block  300  may, for example, measure 0.5 ms by 180 kHz (i.e., assuming a subcarrier spacing of 15 kHz). This example is merely illustrative. In general, resource blocks may be defined as a set of consecutive OFDM symbols of any desired size in the time and frequency domains. 
     Each LTE frequency band (e.g., LTE band 1, LTE band 2, etc.) may include an associated uplink band and an associated downlink band. As an example, LTE band 1 has an uplink band from 1920-1980 MHz and a downlink band from 2110-2170 MHz. As another example, LTE band 5 has an uplink band from 824-849 MHz and a downlink band from 869-894 MHz. During communications operations, a wireless electronic device such as device  10  may transmit radio-frequency signals in the uplink band associated with a desired LTE frequency band and may receive radio-frequency signals in the downlink band associated with the desired LTE frequency band. For example, device  10  may receive radio-frequency signals in the downlink band associated with the desired LTE frequency band while continuously transmitting radio-frequency signals in the uplink band associated with the desired LTE frequency band. 
     Device  10  may transmit radio-frequency signals over a range of frequencies within a selected uplink band (this range of frequencies in a selected uplink band may sometimes be referred to as an uplink channel having an associated channel bandwidth). For example, a device  10  that is configured to transmit radio-frequency signals using LTE band 1 may be configured to transmit signals in an uplink channel centered at 1950 MHz with a channel bandwidth of 10 MHz (e.g., device  10  may transmit signals in a channel between frequencies 1945 MHz and 1955 MHz). In general, a device  10  that is configured to transmit signals using LTE band 1 may transmit signals in an uplink channel centered at any frequency from 1920-1980 MHz given that the channel bandwidth does not include frequencies outside of the frequency range of LTE band 1. Device  10  may receive radio-frequency signals over a range of frequencies within a selected downlink band (this range of frequencies in a selected downlink band may sometimes be referred to as a downlink channel having an associated channel bandwidth). 
     Different LTE bands (e.g., LTE band 1, LTE band 2, etc.) may each require device  10  to transmit and receive radio-frequency signals having selected channel bandwidths. For example, a device  10  that is configured to transmit radio-frequency signals in the uplink band of LTE band 1 may be required to transmit radio-frequency signals having a channel bandwidth of 5 MHz, 10 MHz, 15 MHz, or 20 MHz. In another example, a device  10  that is configured to receive radio-frequency signals in the uplink band of LTE band 5 may be required to receive radio-frequency signals having a channel bandwidth of 1.4 MHz, 3 MHz, 5 MHz, or 10 MHz. In general, each LTE band imposes respective requirements on the allowable channel bandwidth. Each uplink and downlink channel in each LTE band may be identified by a respective channel number such as an Absolute Radio Frequency Channel Number (ARFCN), an E-UTRA Absolute Radio Frequency Channel Number (EARFCN), etc. In other words, each channel may be numbered to identify the channel. Each LTE band may include one or more dedicated control channels over which control signals and measurement data may be conveyed between device  10  and external equipment. Control channels may be formed from reserved resource blocks (i.e., resource blocks that have been assigned to a respective control channel). 
       FIG. 5  shows an illustrative LTE band  302  having multiple channels  304 . Each channel in the LTE band of  FIG. 6  has a corresponding channel bandwidth CBW. Each channel within band  302  may be any numbered channel in the uplink or downlink band of LTE band  302  (e.g., each channel  304  may be any desired uplink or downlink channel of the corresponding LTE band). Each channel  304  may be partitioned in frequency into a number of resource blocks  306 . In general, band  302  may have any desired number of channels having any desired channel bandwidth, and each channel may have any desired number of resource blocks  300 . As an example, each channel  304  may have a channel bandwidth CBW of 10 MHz and 50 resource blocks  300  and band  302  may have four channels  304 . As another example, band  302  may have ten channels  304 . In general, the number of channels and resource blocks in each channel may depend on the LTE band that is being used. 
     Device  10  need not utilize all of its available resource blocks  300 . Device  10  may be configured to transmit or receive in only one resource block  300  or an allocated portion (e.g., a subset) of its resource blocks  300 . If desired, device  10  may be configured to communicate in all available resource blocks. In the example of  FIG. 6 , device  10  communicates using shaded resource blocks  300 ′ (e.g., device  10  may communicate using the third, fourth, fifth, and seventh resource blocks of channel  304 ). The particular resource blocks  300 ′ that are used by device  10  may sometimes be referred to herein as the deployment, allocation, or configuration of resource blocks used by device  10 . The deployment of resource blocks used by device  10  may include any desired number of resource blocks  300  starting at any desired position within the corresponding channel  304 . Resource blocks deployed by device  10  may each be adjacent in frequency or may be separated in frequency by other unused resource blocks (as shown in the example of  FIG. 6 ). During operation, device  10  may be configured to transmit using a particular resource block configuration (e.g., using a selected number of resource blocks beginning at a selected point in the corresponding channel). Similarly, base stations  80  may transmit downlink signals to device  10  using any desired configuration of resource blocks  300 . 
     During communications operations by wireless communications circuitry  4  in device  10 , antenna structures  40  may be used to simultaneously transmit uplink signals and receive downlink signals (e.g., wireless communications circuitry  34  may receive downlink signals in a channel of a downlink band and transmit uplink signals in a channel of an uplink band simultaneously). Duplexer circuitry  66  ( FIG. 3 ) may partition radio-frequency signals into respective uplink and downlink signals. 
     Downlink signals received by antennas  40  may include a digital data stream having a series of binary bits “1” and “0.” The digital data stream may, for example, be encoded using a desired modulation scheme (e.g., QPSK, 16-QAM, 64-QAM, etc.). Circuitry  92  in base stations  80  may include modulation circuitry for generating the downlink signals with a desired modulation scheme and amplifier circuitry for providing downlink signals at a desired downlink power level. Circuitry  92  may generate downlink signals using any desired number of LTE resource blocks (e.g., any desired resource block deployment) in any desired channel of any desired LTE band. Baseband module  54  may extract the digital data stream from the downlink signals received from base stations  80 . The number of bits in the digital data stream that are successfully retrieved by baseband module  54  per second may be defined as the data reception throughput (sometimes referred to as data throughput or receive path data throughput) of wireless communications circuitry  34 . 
     It may be desirable to simultaneously receive and/or transmit radio-frequency signals in two different frequency bands to increase data throughput in wireless communications circuitry  34 . For example, device  10  may communicate with base stations  80  using a Long Term Evolution (LTE) protocol in which cellular base stations  80  may expect device  10  to receive data using two different LTE communications bands (a scheme sometimes referred to as carrier aggregation). As an example, a given base station such as base station  80 - 1  may require device  10  to simultaneously receive data on LTE band 4 and LTE band 17. To receive data on LTE band 4, device  10  may be configured to accommodate frequencies from 2110 MHz to 2155 MHz. To receive data on LTE band 17, device  10  may be configured to accommodate frequencies from 734 MHz to 746 MHz. 
     By receiving data using two different communications bands, device  10  may be provided with increased bandwidth. For example, a device  10  that simultaneously receives data streams in LTE band 4 and LTE band 17 may be provided with a communications bandwidth equal to the combination of the respective bandwidths of LTE band 4 and LTE band 17 (e.g., 45 MHz from LTE band 4 added to 12 MHz from LTE band 17). In this way, device  10  may be provided with improved data transmissions and throughput rates. 
     If desired, device  10  may simultaneously communicate with two or more base stations  80  in two different LTE communications bands (e.g., device  10  may perform carrier aggregation over multiple base stations  80 ). For example, device  10  may simultaneously communicate with a first base station  80 - 1  using LTE band 4 and with a second base station  80 - 2  using LTE band 17. To receive data on LTE band 4 from first base station  80 - 1 , device  10  may be configured to accommodate frequencies from 2110 MHz to 2155 MHz. To receive data on LTE band 17 from second base station  80 - 2 , device  10  may be configured to accommodate frequencies from 734 MHz to 746 MHz. 
     As an example,  FIG. 6  shows one illustrative embodiment of device  10  with wireless communications circuitry  34  that is configured to simultaneously receive radio-frequency transmissions in different frequency bands from two different base stations  80 . In the example of  FIG. 6 , wireless communications circuitry  34  includes a single transmitter and two receivers that are multiplexed with switching circuitry (e.g.,  68  of  FIG. 3 ) to accommodate all communications bands. 
     As shown in  FIG. 4 , wireless communications circuitry  34  may include an antenna such as antenna  40 - 1  that receives wireless transmissions (e.g., from one or more cellular base stations  80 ). Switching circuitry  68  may include multiple switching multiplexers (e.g., switch  68 LB,  68 HB,  68 LBRX,  68 TX, and  68 HBRX may be formed as a part of switching circuitry  68  of  FIG. 3  and may sometimes be referred to herein as switching stages, multiplexers, or switching multiplexers). The received wireless transmission may be provided to diplexer  64  via diplexer port PA. Diplexer  64  may include circuitry that routes signals according to frequency. For example, diplexer  64  may have filters FLB (e.g., a low pass filter) and FHB (e.g., a high pass filter) that divide received wireless transmissions into low frequencies and high frequencies, respectively, while minimizing signal loss (e.g., while minimizing insertion loss). Received signals with low frequencies may be routed to terminal T′ of switch  68 LB from diplexer port PL. Received signals with high frequencies may be routed to terminal T′ of switch  68 HB from diplexer port PH. During signal transmission, low band signals at port PL and high band signals at port PH may be combined by diplexer  64  and the resulting combined signals may be output at port PA. 
     Switches  68 LB and  68 HB may each have one or more terminals T. Switches  68 LB and  68 HB may be electrically controllable switches (e.g., transistor-based switches) that may each be configured by control signals received from control circuitry  52  ( FIG. 3 ) via control paths  76  to couple a selected one of terminals T to terminal T′. Each terminal T of switches  68 LB and  68 HB may be coupled to a respective one of duplexers  66 . Duplexers  66  may each have respective high and low band filters. For example, each duplexer may have a first filter such as filter  102  and a second filter such as filter  104 . Filter  102  and filter  104  may separate radio-frequency signals into separate frequency bands corresponding to a transmit frequency bands and a receive frequency bands. Filters  102  may isolate frequencies that correspond to transmit (uplink) frequencies and provide the isolated frequencies to duplexer circuitry  66 . Switching circuit  68 TX may be configurable via control path  76  to couple transmitter  148  (e.g., a particular transmitter TX that is one of transmitters  48  of  FIG. 3 ) to a desired duplexer  66 . Filters  104  may isolate frequencies that correspond to receive (downlink) frequencies. By configuring the frequency responses of filters  102  and  104 , each duplexer  66  (and an associated terminal T) may be configured to handle signals associated with a particular communications band. For example, a first terminal T may be associated with LTE band 4 and a second terminal T may be associated with LTE band 17. 
     To simultaneously receive radio-frequency transmissions in different frequency bands, filters  104  that are coupled to switch  68 LB may be coupled to switching circuit  68 LBRX and filters  104  that are coupled to switch  68 HB may be coupled to switching circuit  68 HBRX. Switching circuitry  68 LBRX and  68 HBRX may be implemented using electrically controllable switches (e.g., transistor-based switches) that are configurable via control terminals  76 . Switch  68 LBRX may be coupled to a first receiver  150  (e.g., a particular receiver RX 1  that is one of receivers  50  of  FIG. 3 ) and switch  68 HBRX may be coupled to a second receiver  150  (e.g., an additional receiver RX 2  of receiver circuits  50 ). Receiver RX 1  may receive radio-frequency signals that correspond to relatively low frequencies. Receiver RX 2  may receive radio-frequency signals that correspond to relatively high frequencies. 
     As an example, a device  10  that communicates with base stations  80  using the LTE standard may simultaneously receive radio-frequency transmissions in band 4 (e.g., a frequency band that corresponds to relatively high frequencies) from a first base station  80 - 1  and in band 17 (e.g., a frequency band that corresponds to relatively low frequencies) from a second base station  80 - 2  (as shown in  FIG. 3 ). In this scenario, the radio-frequency transmissions received by device  10  via antenna  40 - 1  may be partitioned by diplexer  64  into signals that correspond to band 4 and signals that correspond to band 17. 
     The signals that correspond to band 4 may be received by switch  68 HB and forwarded to a first duplexer  66  that is configured to accommodate the frequencies associated with band 4. The first duplexer  66  may partition the frequencies associated with band 4 into a transmit band and a receive band (e.g., a transmit band corresponding to 1710 MHz through 1755 MHz and a receive band corresponding to 2110 MHz through 2155 MHz) and provide the signals associated with the receive band to multiplexer  68 HBRX and receiver RX 2 . Receiver RX 2  may process the signals associated with the receive band (e.g., receiver RX 2  may demodulate the signals and provide the signals to a baseband processor). 
     The signals that correspond to band 17 may be received by switch  68 LB and forwarded to a second duplexer  66  associated with band 17. The second duplexer  66  may partition the frequencies associated with band 17 into a transmit band and a receive band (e.g., a transmit band corresponding to 704 MHz through 716 MHz and a receive band corresponding to 734 MHz through 746 MHz) and provide the signals associated with the receive band to multiplexer  68 LBRX and receiver RX 1  for processing. 
     To allow receiver RX 1  and RX 2  to simultaneously receive radio-frequency signals in different communications bands, each receiver may, if desired, be coupled to a respective local oscillator. Receiver RX 1  may be coupled to local oscillator LO 1  and receiver RX 2  may be coupled to local oscillator LO 2 . Local oscillators LO 1  and LO 2  may generate signals with appropriate frequencies (e.g., sinusoidal signals or other desired signals with appropriate frequencies) for receivers RX 1  and RX 2  to use for processing radio-frequency signals. For example, receiver RX 1  may receive radio-frequency signals corresponding to LTE band 17. In this scenario, local oscillator LO 1  may be tuned to provide a signal with an appropriate frequency for demodulating radio-frequency signals associated with LTE band 17. 
     The use of two separate local oscillators LO 1  and LO 2  to provide receivers RX 1  and RX 2  with respective signals is merely illustrative. If desired, local oscillating circuitry  156  may provide receivers RX 1  and RX 2  with two signals with different frequencies. For example, local oscillating circuitry  156  may include a single local oscillator configured to generate a first signal at a first frequency and the first signal may be provided to receiver RX 1 . Local oscillating circuitry  156  may also include frequency dividing circuitry configured to use the first signal to generate a second signal at a second frequency and the second signal may be provided to receiver RX 2 . 
     In this way, radio-frequency transmissions that are received by device  10  may be simultaneously processed. By simultaneously processing two different frequency bands, device  10  may be provided with increased communications bandwidth, thereby increasing data throughput and transmission rates. By simultaneously receiving signals in each frequency band from different base stations  80 , device  10  may increase throughput regardless of the geographical location of device  10  relative to a given one of the base stations (e.g., even when device  10  is far away from one of the base stations). 
     The use of the circuitry of  FIG. 6  to handle signals associated with LTE bands  4  and  17  is merely illustrative. Any two different communications bands may be simultaneously received by configuring wireless communications circuitry  34  to accommodate the desired frequency bands. For example, LTE band 2 may be simultaneously received with LTE band 17, LTE band 5, the MediaFLO band, or other desired frequency bands. As another example, LTE band 4 may be simultaneously received with LTE band 5 or the MediaFLO band, LTE band 1 may be simultaneously received with LTE band 8 or with LTE band 20, LTE band 3 may be simultaneously received with LTE band 8 or band 20, etc. If desired, more than two frequency bands may be simultaneously handled in this way. For example, multiple diplexers may be arranged in stages to divide received radio-frequency signals into a desired number of frequency bands that are processed by respective receivers, triplexers may be used to divide received radio-frequency signals into three frequency bands, quadplexers may be used to divide signals into four frequency bands, any desired number of transmitters TX and receivers RX may be used to transmit and receive signals in any desired number of bands using any desired number of antennas  40 , etc. 
     Receivers RX 1  and RX 2  may be formed as part of transceiver circuitry or as separate circuits. For example, receiver RX 1  and/or receiver RX 2  may be combined with transmitter TX to form a transceiver or may be implemented separately as distinct receiver and transmitter circuits. If desired, a first optional transceiver  154  may be formed from the combination of receiver RX 1  and transmitter TX and a second optional transceiver  154  may be formed from the combination of receiver RX 2  and an additional transmitter TX. 
     Receivers RX 1  and RX 2  and transmitter TX may be coupled to baseband processor circuitry  54 . Receivers RX 1  and RX 2  may process radio-frequency signals received from switches  68 LBRX and  68 HBRX and provide the processed radio-frequency signals to baseband processor circuitry  54 . For example, receiver RX 1  may receive radio-frequency signals corresponding to LTE band 17 and demodulate the radio-frequency signals to form baseband signals. In this scenario, the baseband signals may be processed by baseband processor circuitry  152 . For example, baseband processor circuitry  54  may decode a modulation scheme associated with the received signals. Baseband processor circuitry  54  may merge the signals that were simultaneously received over each of the bands into a single data stream. 
       FIG. 7  is a graph showing illustrative bands of radio-frequency signals that may be handled using the circuitry of  FIG. 6 . In the example of  FIG. 7 , frequency band LBTX may correspond to a low transmit frequency band such as 704-716 MHz for LTE band 17 and LBRX may correspond to a low receive frequency band such as 734-746 MHz for LTE band 17 (e.g., LBTX may correspond to the transmit band of LTE band 17 and LBRX may correspond to the receive band of LTE band 17). Frequency band HBTX may correspond to a high transmit frequency band such as 1710-1755 MHz for LTE band 4 and HBRX may correspond to a high receive frequency band such as 2110-2155 MHz for LTE band 4 (e.g., HBTX may correspond to the transmit band of LTE band 4 and HBRX may correspond to the receive band of LTE band 4). 
     Diplexer  64  may be configured to partition the radio-frequency transmissions into a first signal partition of frequencies below F 1  and a second signal partition of frequencies above F 1  (e.g., filter FLB may be configured to provide the first signal partition to switch  68 LB and filter HLB may be configured to provide the second signal partition to switch  68 HB). Switch  68 LB may be configured to couple a first duplexer  66  associated with frequency bands LBTX and LBRX to filter FLB. Switch  68 HB may be configured to couple a second duplexer  66  associated with frequency bands HBTX and HBRX to filter HLB. 
     First duplexer  66  may be configured to isolate low transmit band LBTX from low receive band LBRX (e.g., using filters to isolate frequencies lower than F 2  from frequencies higher than F 2 ). Second duplexer  66  may be configured to isolate high transmit band HBTX from high receive band HBRX (e.g., using filters to isolate frequencies lower than F 3  from frequencies higher than F 3 ). Low receive band LBRX may be provided to a first receiver RX 1  and high receive band HBRX may be provided to a second receiver RX 2 . In this way, two different frequency bands may be simultaneously received and processed by wireless communications circuitry  34 . 
       FIG. 8  is an illustrative diagram showing how device  10  may perform carrier aggregation using two wireless base stations  80  (e.g., two cellular communications towers) at different geographical locations in a network (e.g., a cellular network). As shown in  FIG. 6 , device  10  may be located at geographic location  160 . Network  180  may include first and second wireless base stations  80 - 1  and  80 - 2 . Network  180  may be operated by one or more network operators or managers (e.g., one or more network providers). First base station  80 - 1  may be located at geographic location  162  and a second base station  80 - 2  may be located at geographic location  164 . First base station  80 - 1  may have a region of wireless coverage  166 . Region  166  may represent the locations at which first base station  80 - 1  can adequately transmit and receive radio-frequency signals with a wireless device such as device  10  (e.g., a region of wireless coverage in which first base station  80 - 1  can transmit and/or receive signals with a wireless device without dropping the wireless link between base station  80 - 1  and the wireless device, a region in which the wireless device can receive signals from first base station  80 - 1  at a desired signal power level, a region in which base station  80 - 1  can receive signals from the wireless device at a desired signal power level, a region in which signals received by the wireless device and/or base station  80 - 1  have sufficient signal quality, etc.). 
     In one suitable arrangement, base station  80 - 1  may communicate with wireless devices within coverage region  166  using a desired communications band. In another suitable arrangement, region  166  may be divided into two or more zones of coverage  168  each having a corresponding communications band with which base station  80 - 1  communicates with wireless devices within that zone  168 . In the example of  FIG. 6 , region  166  is divided into four coverage zones  168  each having a respective communications band (e.g., a first zone  168 - 1  having a first communications band F A , a second zone  168 - 2  having a second communications band F B , a third zone  168 - 3  having a third communications band F c , and a fourth zone  168 - 4  having a fourth communications band F D ). In this scenario, wireless electronic device  10  is at location  160  that is within zone  168 - 2  of first base station  80 - 1 , and first base station  80 - 1  may communicate with device  10  using the corresponding communications band F B . 
     Second base station  80 - 2  may communicate with wireless devices within coverage region  170  using a desired communications band. In another suitable arrangement, region  170  may be divided into two or more zones of coverage  172  each having a corresponding communications band with which base station  80 - 2  communicates with wireless devices within that zone  172 . In the example of  FIG. 8 , region  170  is divided into four coverage zones  172  each having a respective communications band (e.g., a first zone  172 - 1  having a fifth communications band F E , a second zone  172 - 2  having a second communications band F F , a third zone  172 - 3  having a third communications band F G , and a fourth zone  172 - 4  having a fourth communications band F E ). In this scenario, wireless electronic device  10  is at location  160  that is within zone  172 - 4  of second base station  80 - 2 , and second base station  80 - 2  may communicate with device  10  using the corresponding communications band F E . 
     When device  10  is located within the wireless coverage region of multiple base stations  80 , device  10  may perform carrier aggregation using multiple base stations  80  so that wireless signals are simultaneously received from the base stations in different communications bands (e.g., with improved data throughput relative to communications over a single communications band). In the example of  FIG. 8 , device  10  is located within an overlapping region  174  between coverage region  166  associated with first base station  80 - 1  and coverage region  170  associated with second base station  80 - 2 , and may perform carrier aggregation to simultaneously communicate with both first base station  80 - 1  and second base station  80 - 2 . When performing carrier aggregation, device  10  may perform communications operations with each base station  80  in the communication band associated with the coverage zone in which device  10  is located. For example, as shown in  FIG. 6 , device  10  may perform carrier aggregation to simultaneously communicate with first base station  80 - 1  in communications band F B  and with second base station  80 - 2  in communications band F E . 
     As one example, band F B  may include relatively high frequencies, whereas frequency band F E  may include relatively low frequencies. Diplexer circuitry  64  in device  10  may route signals received in low band F E  from base station  80 - 2  to switch  68 LB for conveying to first receiver RX 1  (as shown in  FIG. 4 ) and may route signals received in high band F B  from base station  80 - 1  to switch  68 HB for conveying to second receiver RX 2 . In scenarios where device  10  communicates with base stations  80  using the LTE standard, device  10  may simultaneously receive radio-frequency transmissions in band 4 (e.g., a frequency band that corresponds to relatively high frequencies) from first base station  80 - 1  and in band 17 (e.g., a frequency band that corresponds to relatively low frequencies) from second base station  80 - 2  (e.g., band F B  may be LTE band 4 and band F E  may be LTE band 17). In this scenario, the radio-frequency transmissions received by device  10  may be partitioned by diplexer  64  into signals that correspond to band 4 and signals that correspond to band 17. This example is merely illustrative. If desired, each coverage zone  168  and  172  may correspond to a respective channel  304  within an associated LTE band or may correspond to any other desired frequency range. If desired, the configuration of switching circuitry  68 , duplexers  66 , and/or diplexer  64  may be adjusted (e.g., using control signals generated by control circuitry  52 ) to route signals received simultaneously from multiple base stations  80  in different bands to the corresponding receiver circuits  50  for handling signals at those frequencies. 
     The example of  FIG. 8  is merely illustrative. If desired, coverage regions  166  and  170  may have any desired shape (e.g., the shape of coverage regions  166  and  170  may be determined by the configuration of the wireless circuitry and antennas  98  on base stations  80 , by the geography and topography of the area in which base stations  80  are located, by objects such as trees or buildings surrounding the base stations, etc.). Coverage regions such as regions  166  and  170  may have any desired number of coverage zones for handling radio-frequency signals in any desired number of communications bands. If desired, one or more of coverage zones  172  of second base station  80 - 2  may have associated communications bands that are the same as one or more of coverage zones  168  of first base station  80 - 1 . Device  10  may perform carrier aggregation with any desired number of base stations  80  (e.g., overlapping coverage region  174  may be located within the coverage regions of three, four, or more than four base stations). For example, device  10  may simultaneously receive signals from three base stations  80 , four base stations  80 , more than four base stations  80 , etc. 
     Each base station  80  may maintain information about other nearby base stations  80  in storage circuitry  92  (as shown in  FIG. 3 ). For example, in the embodiment of  FIG. 6 , base station  80 - 1  may store information  96  that identifies base station  172  as a neighboring base station. Information  96  may include information identifying coverage region  170  and the corresponding zones  172  associated with base station  172 . For example, information  96  may include information about which coverage zones  172  and the corresponding communication bands of base station  80 - 2  overlap with coverage zones  168  of base station  80 - 1  (e.g., base station  80 - 1  may include information  96  that identifies that coverage zone  172 - 4  of base station  80 - 2  has a corresponding communications band F E  and overlaps with coverage zone  168 - 2  of base station  80 - 1  in which device  10  is located). 
     If desired, neighboring base station information  96  may be predetermined and stored on storage  92  prior to communications with device  10 . For example, a network operator associated with base stations  80  may load information  96  onto base stations  80  so that each base station stores information about the neighboring base stations and how the corresponding coverage zones overlap in space. As the operating conditions of network  180  can change over time, neighboring base station information may be updated during normal operations of network  180  so that information  96  reflects any changes to network  180 . For example, neighboring base station information  96  may be manually or automatically updated to reflect changes in network  180  such as when additional base stations  80  are added to network  180 , when base stations  80  are removed from network  180 , when neighboring base stations change their corresponding zones or regions of coverage, when neighboring base stations change frequency bands, etc. If desired, each base station  80  may be coupled together using wired or wireless communications links so that information such as handover information, updated neighboring base station information  96 , control signals, or information about wireless devices such as device  10  (e.g., device information  94  of  FIG. 3 ) can be conveyed between base stations  80 . 
     When performing carrier aggregation with multiple base stations  80 , device  10  may first establish a wireless connection with a single base station such as base station  80 - 1 . The first base station with which device  10  establishes a wireless may sometimes be referred to herein as Primary Component Carriers (PCCs) or primary base stations. Radio-frequency signals conveyed between the PCC and device  10  may sometimes be referred to herein as primary component carrier signals, primary signals, primary component signals, primary carrier signals, or PCC signals, and the wireless links between the primary base stations and device  10  may sometimes be referred to herein as primary connections or primary wireless links. Once a connection is established between device  10  and the PCC, device  10  may establish an additional wireless connection with another base station  80  such as base station  80 - 2  without dropping the connection with the primary base station, and may simultaneously communicate with both base stations (e.g., using different frequency bands in a carrier aggregation scheme). Additional base stations that establish a connection with device  10  after device  10  has established a wireless connection with a primary base station may sometimes be referred to herein as Secondary Component Carriers (SCCs) or secondary base stations. Radio-frequency signals conveyed between the SCCs and device  10  may sometimes be referred to herein as secondary component carrier signals, secondary signals, secondary component signals, secondary carrier signals, or SCC signals, and the wireless links between the secondary base stations and device  10  may sometimes be referred to herein as secondary connections or secondary wireless links. Device  10  may establish a connection with a primary base station and one or more secondary base stations in downlink and uplink communications bands. 
     When establishing a connection with a base station  80 , device  10  and the base station may compare received signals (e.g., computed performance metric information associated with the received signals) to predetermined performance metric standards to determine whether an adequate connection has been established. For example, device  10  may measure a signal strength of the received signals and may compare the measured signal strength to a signal strength threshold. If the measured signal strength is greater than the threshold, device  10  may determine that an adequate connection has been established. 
     Base stations  80  and device  10  may establish a wireless connection using a set of connection settings (sometimes referred to herein as device connection settings, wireless connection settings, or wireless device connection settings). The connection settings may include any desired settings associated with the configuration of wireless circuitry in base stations  80  and the configuration of wireless circuitry  34  (e.g., configurations for duplexers  66 , diplexers  64 , switching circuitry  68 , antennas  40 , amplifiers  72  and  74 , transceiver  90 , and baseband circuitry  54  of device  10 ) for establishing a wireless connection between device  10  and base stations  80  and for transmitting and/or receiving wireless signals between device  10  and base stations  80 . As an example, the connection settings may include uplink power level settings (e.g., the uplink power level provided to transmitted signals by amplifiers  72  in device  10 ), downlink power level settings (e.g., the downlink power level provided to transmitted signals by amplifiers in base stations  80 ), power amplifier offset settings, power ratio index settings, path loss adjustment settings (offsets), uplink and downlink code rate settings, uplink and downlink data rate settings (e.g., data rates associated with the uplink and downlink signals generated by device  10  and base stations  80 ), uplink and downlink modulation scheme settings (e.g., modulation schemes used by baseband processor  54  and/or base station  80  to modulate uplink and downlink signals), uplink and downlink resource block deployment settings (e.g., the number of resource blocks to use for transmitting uplink and downlink signals), throughput settings, scheduling settings, target power level settings, uplink and downlink bandwidth settings, uplink and downlink channel settings, frequency settings, cyclic prefix settings, or any other desired wireless connection settings. 
     Device  10  and a given base station  80  may attempt to establish a connection using first set of connection settings (e.g., using a first downlink or uplink power level, bandwidth setting, resource block configuration, etc.). If an adequate wireless connection cannot be established using the first connection settings (e.g., if signals received by the base station and/or device  10  are characterized by insufficient performance metric information), device  10  and/or base station  80  may cycle through different connection settings until an adequate connection is established. Establishing a wireless connection between device  10  and base stations  80  in such a manner can be time consuming and can, when performed for additional base stations such as when establishing a wireless connection using carrier aggregation (sometimes referred to herein as establishing a carrier aggregation link) with multiple base stations  80 , result in delays in establishing a wireless connection and device  10 . It may therefore be desirable to be able to provide improved methods for establishing a wireless connection for performing carrier aggregation between an electronic device and wireless base stations. 
     To communicate in a carrier aggregation mode (e.g., to communicate between cellular base stations  80  and a wireless device  10  using simultaneous radio-frequency transmissions in different communications bands over a carrier aggregation link), the steps of the illustrative flowchart of  FIG. 9  may be performed. 
     At step  202 , a first cellular base station such as base station  80 - 1  of  FIG. 6 , a second cellular base station such as base station  80 - 2 , and wireless electronic device  10  may prepare for carrier aggregation operations. For example, device  10  may establish a first (primary) connection with first base station  80 - 1  using selected connection settings. Base stations  80  may prepare for transmission of multiple data streams and may instruct the wireless electronic device to prepare for simultaneous receipt of multiple data streams in different communications bands (e.g., base station  80 - 1  or base station  80 - 2  may instruct the wireless electronic device to operate in a carrier aggregation mode). The multiple data streams may be generated by dividing a single source data stream into multiple portions (e.g., a single source data stream may be divided into first and second portions and provided from other networking equipment in network  180  to base stations  80 - 1  and  80 - 2 , respectively). In response to receiving instructions to prepare for simultaneous receipt of multiple data streams, the wireless electronic device may configure switches  68  to make appropriate routing connections (e.g., the switches may be configured to route each communications band to a respective receiver  50 ). 
     If desired, first base station  80 - 1  may determine whether device  10  is to operate in carrier aggregation mode prior to instructing device  10  to prepare for carrier aggregation. For example, first base station  80 - 1  may identify a coverage zone (e.g., coverage zone  168 - 2 ) in which device  10  is located and may identify whether that coverage zone overlaps in space with a coverage zone of second base station  80 - 2  based on stored neighboring base station information  96 . If the coverage zone of second base station  80 - 2  overlaps with the coverage zone of base station  80 - 1  in which device  10  is located, first base station may instruct device  10  to configure wireless circuitry  34  for carrier aggregation (e.g., base station  80 - 1  may instruct device  10  to perform carrier aggregation in a communications band corresponding to the coverage zone  172  of second base station  80 - 2  in which device  10  is located and device  10  may configure switching circuitry  68 , diplexer circuitry  64 , and duplexer circuitry  66  to handle simultaneous communications in that communications band and the communications band that is being used by first base station  80 - 1 ). In another suitable arrangement, device  10  may determine whether to operate in carrier aggregation mode. For example, if data throughput is satisfactory without using carrier aggregation, device  10  may determine that carrier aggregation operations are not necessary and may subsequently communicate with base station  80 - 1  using a single frequency band. 
     Once device  10  has prepared for simultaneous receipt of multiple data streams in different communications bands, device  10  may establish a connection with second base station  80 - 1 . Using the example of  FIG. 8 , device  10  may first establish a primary connection with first base station  80 - 1 . Device  10  may establish the primary connection with first base station  80 - 1  using selected connection settings (e.g., device  10  may communicate with first base station  80 - 1  in communications band F B  corresponding to the coverage zone in which device  10  is located, with selected uplink and downlink power levels, modulation schemes, etc.). First base station  80 - 1  may identify that device  10  is located in coverage zone  168 - 2  having corresponding frequency band F B . First base station  80 - 1  may identify that second base station  80 - 2  has a coverage zone  172 - 4  and corresponding frequency band F E  that overlaps with coverage zone  168 - 2  based on stored neighboring base station information  96 . First base station  80 - 1  may subsequently instruct device  10  to prepare for carrier aggregation using frequency bands F B  and F E . Control circuitry  52  in device  10  may provide control signals to front end circuitry  60  over path  76  to configure diplexer circuitry  64 , duplexer circuitry  66 , and switching circuitry  68  to handle simultaneous transmission/reception of signals in frequency bands F B  and F E . Device  10  may subsequently establish a secondary wireless connection with second base station  80 - 2  in communications band F E . 
     At step  204 , base stations  80  may simultaneously transmit multiple data streams on different communications bands to wireless electronic device  10 . For example, first base station  80 - 1  may transmit a first data stream on LTE band 17 and second base station  80 - 2  may transmit a second data stream on LTE band 4. 
     At step  206 , electronic device  10  may use multiplexing circuitry such as diplexer  64  and duplexers  66  to divide radio-frequency signals that are received from base stations  80 - 1  and  80 - 2  based on frequency. For example, electronic device  10  may use diplexer  64  to divide radio-frequency signals received by an antenna  40 - 1  from base stations  80 - 1  and  80 - 2  into relatively low frequencies and relatively high frequencies. The relatively low frequencies may be provided to a first switch  68 LB that has been configured (e.g., configured during step  202 ) to route the relatively low frequencies to a first duplexer  66 . The relatively high frequencies may be provided to a second switch  68 HB and routed to a second duplexer  66 . The first duplexer  66  may isolate a first data stream received from base station  80 - 1  at the relatively low frequencies and provide the first data stream to receiver RX 1 . The second duplexer  66  may isolate a second data stream from the relatively high frequencies and provide the second data stream to receiver RX 2 . 
     At step  208 , electronic device  10  may simultaneously receive the multiple data streams using multiple receivers. For example, receiver RX 1  may demodulate a first data stream and provide the demodulated first data stream to the base station. Receiver RX 2  may demodulate a second data stream and provide the demodulated second data stream to baseband processing circuitry  54 . 
     At step  210 , baseband processing circuitry  54  may simultaneously receive the demodulated first and second data streams and combine the demodulated first and second data streams to reconstruct the single source data stream. 
       FIG. 10  shows a flow chart of illustrative steps that may be performed by base stations  80  in a cellular network such as network  180  of  FIG. 6  for preparing device  10  and base stations  80  for carrier aggregation operations (e.g., for establishing primary and secondary connections between device  10  and base stations  80 ). The steps of  FIG. 8  may, for example, be performed while processing step  202  of  FIG. 7 . 
     At step  212 , first base station  80 - 1  may establish a primary connection with device  10 . For example, device  10  may send a wireless request to first base station  80 - 1  and base station  80 - 1  may send a wireless response to device  10 . Device  10  may attempt to establish the connection with first base station  80 - 1  using selected connection settings (e.g., selected uplink and downlink connection settings). In one suitable arrangement, device  10  and base station  80 - 1  may cycle through connection settings until an adequate connection between base station  80 - 1  and device  10  is established. The connection settings with which the connection between device  10  and base station  80 - 1  was successfully established may be stored as a portion of device information  94  on storage circuitry  92 . 
     If desired, first base station  80 - 1  may receive device identification information from device  10  (e.g., a unique device identification number, registration number, serial number, time stamp information, geo-location information such as GPS information associated with the geographic location of device  10 , etc.). First base station  80 - 1  may store the received device identification information as a portion of device information  94  on storage circuitry  92 . If desired, base station  80 - 1  may identify a coverage zone  168  in which device  10  is located and may store the information about the identified coverage zone as a portion of device information  94 . 
     First base station  80 - 1  may compare device information  94  to stored neighboring base station information  96  to determine whether to instruct device  10  to prepare for carrier aggregation with an additional (SCC) base station. For example, base station  80 - 1  may determine whether neighboring base station information  96  identifies a neighboring base station having a coverage region  170  that overlaps with coverage zone  168  in which device  10  is located. In another suitable arrangement, base station  80 - 1  may compare geo-location information received from device  10  to neighboring base station information  96  to determine whether device  10  is within an overlapping coverage region  170 . If base station  80 - 1  determines that device  10  is located within a region of coverage associated with an additional base station such as base station  80 - 2 , device  10  may identify a corresponding frequency band associated with the coverage zone  172  of the additional base station in which device  10  is located. 
     At step  214 , first base station  80 - 1  may broadcast device information  94  associated with device  10  to other base stations  80  in network  180 . In one suitable arrangement, first base station  80 - 1  may broadcast device information  94  to all neighboring base stations identified in stored neighboring base station information  96 . In another suitable arrangement, base station  80 - 1  may broadcast device information  94  to the base station  80 - 2  having the coverage region  170  in which device  10  is located. Second base station  80 - 2  may store device information  94  associated with device  10  in the corresponding circuitry  92 . 
     At step  216 , first base station  80 - 1  may transmit some or all of neighboring base station information  96  to device  10  to instruct device  10  to prepare for carrier aggregation operations in the frequency band associated with additional base station  80 - 2 . Device  10  may use the neighboring base station information to broadcast a connection request (e.g., in the frequency band identified by the neighboring base station information). This step is merely illustrative. If desired, step  216  may be performed prior to step  214  to broadcast the device information before broadcasting the neighboring base station information. 
     At step  218 , second base station  80 - 2  may wait until a request to establish a wireless connection is received from a wireless device. Once second base station  80 - 2  has received a request to establish a connection from a wireless device (e.g., a request from a wireless device within coverage region  170 ), processing may proceed to step  220 . 
     At step  220 , second base station  80 - 2  may retrieve device information associated with the wireless device that sent the request. For example, second base station  80 - 2  may identify device information included within the received request or base station  80 - 2  may request the device information after receiving the request to establish the connection from the wireless device. The retrieved device information may include, for example, a unique device identification number, registration number, serial number, time stamp information, geo-location information such as GPS information associated with the geographic location of device  10 , or any other desired information about the device that sent the request to establish the connection. 
     At step  222 , second base station  80 - 2  may compare the retrieved device information to device information  94  received from first base station  80 - 1  to determine whether the wireless device that sent the request is the wireless device for which base station  80 - 1  is attempting to prepare for carrier aggregation. If the received device information does not match device information  94  (e.g., if the device that sent the request is a wireless device in coverage region  170  other than device  10  that is independently attempting to establish a connection, etc.), processing may loop back to step  218  (as shown by path  224 ) to wait for additional requests to establish a connection. In this way, base station  80 - 2  may avoid attempting to establish a carrier aggregation connection with devices that are not in communication with other base stations  80  in network  180  or that are not attempting to establish a carrier aggregation connection. If desired, base station  80 - 2  may establish an independent wireless connection with other wireless devices that do not match device information  94 . 
     If the received device information matches device information  94  (e.g., if the wireless device that sent the request to base station  80 - 2  is the same device that established the primary connection with base station  80 - 1 ), processing may proceed to step  228  as shown by path  226 . 
     At step  228 , base station  80 - 2  may establish a secondary wireless connection with device  10  using one or more of the device connection settings received from first base station  80 - 1 . If desired, base station  80 - 2  may clone one or more of the device connection settings with which a successful connection was established with first base station  80 - 1  when attempting to establish a connection with device  10 . For example, secondary base station  80 - 2  may use the same downlink power level, modulation scheme, resource block deployment, and/or bandwidth that were used to establish the primary connection between device  10  and primary base station  80 - 1 . As the cloned connection settings have already been used to successfully connect to device  10  using base station  80 - 1 , there is a high probability that one or more of the connection settings can also be used to successfully connect to device  10  using base station  80 - 2 . In this way, second base station  80 - 2  may establish a connection without cycling through possible connection settings until a connection is successfully established or requesting optimal connection settings from an additional source, thereby reducing the time required to establish the secondary connection with secondary base station  80 - 2  relative to the time required to establish the primary connection between device  10  and primary base station  80 - 1 . Steps  214 - 228  may be performed while the primary connection between device  10  and primary base station  80 - 1  is maintained (e.g., the secondary connection between device  10  and secondary base station  80 - 2  may be set up without dropping the primary connection between device  10  and primary base station  80 - 1 . 
     If desired, the steps of  FIG. 10  may be used to establish additional secondary connections with additional base stations  80 . For example, device  10  may perform carrier aggregation to simultaneously send and receive signals with a primary component carrier station (e.g., base station  80 - 1 ) and two secondary component carrier stations. In this example, a single data stream may be divided into three parallel data streams that are conveyed between device  10  and each of the three base stations using different respective frequency bands. In general, any desired number of secondary base stations may be used in simultaneously communicating with device  10  in conjunction with primary base station  80 - 1 . 
       FIG. 11  shows a flow chart of illustrative steps that may be performed by device  10  to establish a carrier aggregation connection with multiple base stations  80  in a cellular network such as network  180  of  FIG. 8 . The steps of  FIG. 11  may, for example, be performed while processing step  202  of  FIG. 9 . 
     At step  240 , device  10  may establish a connection with primary base station  80 - 1  using selected connection settings. As an example, device  10  may send a request to connect to base station  80 - 1  and may receive a response to the request from base station  80 - 1 . Device  10  and/or base station  80 - 1  may determine successful connection settings with which a successful communications link is established between device  10  and base station  80 - 1 . As an example, if a first set of connection settings between device  10  and base station  80 - 1  are unsuccessful at establishing an adequate wireless link, a second set of connection settings may be used to establish the link. Once a successful connection has been established, processing may proceed to step  242 . Device  10  and/or base station  80 - 1  may store the successful connection settings with which device  10  established the connection with base station  80 - 1 . 
     At step  242 , device  10  may begin data communications operations with base station  80 - 1  using the selected connection settings. Device  10  may, for example, send normal communications data (e.g., cellular voice data and non-voice data), may send device identification information, or any other desired data to device  10 . If desired, device  10  may wait until a successful carrier aggregation connection has been established with multiple base stations before sending normal communications data to base station  80 - 1 . 
     At step  244 , device  10  may receive neighboring base station information such as neighboring base station information  96  of  FIG. 3  from base station  80 - 1 . Device  10  may process the received base station information to determine whether to request a secondary connection with an additional base station  80  in network  180 . If device  10  determines that the received base station information identifies a suitable base station  80  with which to establish a secondary connection (e.g., if the received base station information identifies a second base station such as base station  80 - 2  of  FIG. 8  having a wireless coverage region that includes the location of device  10 ), processing may proceed to step  246 . The received base station information may include, for example, a command issued by base station  80 - 1  for device  10  to establish a connection with additional base stations  80 , information about which frequency band to use to establish the connection with additional base stations  80 , etc. If desired, device  10  may determine not to perform carrier aggregation (e.g., if the data throughput on the device is satisfactory, etc.), in which case device  10  may subsequently perform normal communication operations with first base station  80 - 1 . 
     At step  246 , device  10  may send a request to establish a secondary connection to other base stations  80  in network  180  (e.g., base stations other than primary base station  80 - 1  to which device  10  is already connected) based on the neighboring base station information received from base station  80 - 1 . For example, device  10  may configure wireless circuitry  34  for simultaneous communications in the frequency band associated with neighboring base station  80 - 2  and in the frequency band associated with primary base station  80 - 1  (e.g., by configuring switching circuitry  68 , diplexer circuitry  64 , and duplexer circuitry  66  to route signals between appropriate transmitters  48 , receivers  50 , and antennas  40 ). Device  10  may broadcast a request to establish a connection over a frequency band identified in the received neighboring base station information as corresponding to the coverage zone  172  of neighboring base station  80 - 2  in which device  10  is located. In another suitable arrangement, the received neighboring base station information may include a command issued by base station  80 - 1  that instructs device  10  to broadcast the request over an appropriate frequency band used by base station  80 - 2 . By using the received neighboring base station information to broadcast requests to establish a secondary connection, device  10  may omit broadcasting requests over frequency bands that are not in use by neighboring base station  80 - 2 , thereby reducing the amount of time required to establish the carrier aggregation connection. 
     At step  248 , device  10  may wait for a confirmation from neighboring base station  80 - 2  that a secondary connection is to be established. Device  10  may maintain the primary connection with primary base station  80 - 1  while waiting for confirmation from neighboring base station  80 - 2  (e.g., the configuration of wireless circuitry  34  may allow simultaneous communications over primary and one or more secondary connections without dropping the primary connection). Once a confirmation is received from neighboring base station  80 - 2  that a secondary connection is to be established, processing may proceed to step  250 . 
     At step  250 , device  10  and base station  80 - 2  may establish a secondary connection. While establishing the secondary connection, device  10  may receive downlink signals from neighboring base station  80 - 2  that were transmitted using one or more of the selected connection settings with which the connection between first base station  80 - 1  and device  10  was established. Base station  80 - 2  may send control signals to device  10  to instruct device  10  to transmit uplink signals using one or more of the selected connection settings with which the connection between first base station  80 - 1  and device  10  was established. In this way, a satisfactory wireless connection may be established between neighboring base station  80 - 2  and device  10  in less time than in scenarios where base station  80 - 2  is unaware of the connection settings used in establishing the primary connection between device  10  and primary base station  80 - 1 . Device  10  may subsequently begin normal data communications operations using carrier aggregation between primary base station  80 - 1  and secondary base station  80 - 2  to provide device  10  with improved data throughput relative to communications schemes in which only a single frequency band is used. 
       FIG. 12  shows a table  398  of connection settings that may be used in establishing the primary connection between device  10  and first base station  80 - 1  and in establishing the secondary connection between device  10  and second base station  80 - 2 . The information in table  398  of  FIG. 12  may, for example, be stored as a portion of device information  94  on first base station  80 - 1 , and may therefore sometimes be referred to herein as device connection settings  398  or device connection information  398 . First base station  80 - 1  may generate and store device connection information  398  once a successful connection has been established with device  10  (e.g., after processing step  212  of  FIG. 8 ) and may broadcast connection information  398  to neighboring base stations  80  in network  180  (e.g., while processing step  214  of  FIG. 8 ). 
     Each entry (row) of connection information  398  may correspond to a connection setting used by base station  80 - 1  and/or device  10  to successfully establish the primary connection between the base station and the device. Entries in connection information  398  may include connection settings associated with the generation and transmission of uplink signals such as uplink connection settings  404  and may include connection settings associated with the generation and transmission of downlink signals such as downlink connection settings  406 . Device  10  may, for example, use one or more of connection settings  404  to transmit uplink signals to base stations  80 . Base stations  80  may, for example, use one or more of connection settings  406  to transmit downlink signals to device  10 . If desired, primary base station  80 - 1  and/or secondary base station  80 - 2  may instruct device  10  to transmit secondary signals to base station  80 - 2  (e.g., to establish a secondary connection) using settings  404  or device  10  may transmit secondary signals to secondary base station  80 - 2  based on predetermined uplink connection settings stored on storage and processing circuitry  28  that are already in use between device  10  and primary base station  80 - 1 . Secondary base station  80 - 2  may clone (copy) one or more entries of device connection settings  398  when establishing the secondary connection between device  10  and base station  80 - 2  (e.g., while processing step  228  of  FIG. 10 ). 
     Column  400  of table  398  includes connection settings associated with the established connection between device  10  and base station  80 - 1 . Column  402  includes examples of values corresponding to each connection setting in column  400 . In the example of  FIG. 12 , uplink connection settings  404  include the number of resource blocks  300  used by device  10  to transmit uplink signals to base stations  80  (e.g., device  10  may transmit uplink signals using 25 resource blocks  300 ), the starting resource block in the corresponding channel  304  to use for transmitting the uplink signals (e.g., device  10  may transmit the uplink signals using 25 resource blocks  300  beginning with the first resource block in the channel), the modulation scheme with which the uplink signals are generated (e.g., device  10  may modulate the uplink signals using a QPSK modulation scheme), the uplink data rate to use when generating the uplink signals (e.g., device  10  may generate the uplink signals having an uplink data rate A), the uplink power level provided by power amplifier  72  (e.g., power amplifiers  72  may provide uplink signals at a power level B), a path loss compensation value to be added to the uplink signals (e.g., a path loss compensation value E may be added to the uplink signals by device  10  and/or base stations  80 ), and a channel bandwidth to use for generating the uplink signals (e.g., device  10  may generate the uplink signals having channel bandwidth F). This example is merely illustrative. In general, any desired uplink connection settings  404  may be stored and used for transmitting uplink signals (e.g., settings  404  may include the particular deployment of resource blocks  300  to use, the frequency channel of a particular LTE band to use, etc.). Device  10  may use uplink settings  404  to configure baseband circuitry  54 , amplifier circuitry  72 , front end circuitry  60 , antennas  40 , and/or transceivers  90  to generate corresponding uplink signals that are to be transmitted to base stations  80 - 1  and  80 - 2  using a carrier aggregation communications scheme (e.g., over a carrier aggregation link). 
     In the example of  FIG. 12 , downlink connection settings  406  include the number of downlink resource blocks  300  used by base stations  80  to transmit downlink signals to device  10 , the starting resource block for transmitting the downlink signals, the modulation scheme used to generate the downlink signals, the downlink data rate, downlink power level, downlink power offset level, downlink channel bandwidth, etc. This example is merely illustrative. In general, any desired downlink connection settings  406  may be stored and used for transmitting downlink signals. Base stations  80  may use downlink settings  406  to configure corresponding wireless circuitry to generate and transmit the desired downlink signals to device  10 . If desired, device  10  may use downlink settings  406  to configure baseband circuitry  54 , amplifier circuitry  74 , front end circuitry  60 , antennas  40 , and/or transceivers  90  for preparing to receive and process corresponding downlink signals from base stations  80 . 
     Second base station  80 - 2  may use any desired number of device connection settings  398  to establish the secondary connection between base station  80 - 2  and device  10 . In one suitable arrangement, secondary base station  80 - 2  may clone all of the connection settings in table  398  for establishing the secondary connection. However, in some scenarios, such as when device  10  is located at different distances with respect to base station  80 - 1  and base station  80 - 2 , some connection settings  398  such as uplink and downlink power level may be omitted from cloning at secondary base station  80 - 2  (e.g., because the path loss between base stations  80 - 1 ,  80 - 2  and device  10  would be different in such a scenario). In this scenario, base station  80 - 2  may determine power levels to use in establishing the secondary connection using any desired algorithm (e.g., by cycling through different power levels, etc.). In general, any desired number of connection settings  398  may be cloned at secondary base station  80 - 2  for establishing the secondary connection with device  10 . As settings  398  were previously used to establish a successful connection between device  10  and primary base station  80 - 1 , second base station  80 - 2  may establish a successful secondary connection with device  10  using one or more of the same connection settings, thereby reducing the amount of time required to establish the secondary connection. In this way, base stations  80  and device  10  may rapidly set up and begin high-throughput carrier aggregation operations between base stations  80  and device  10 . 
     If desired, base stations  80  and device  10  may be operable in a test mode of operation for performing wireless test operations or in a normal mode of operation. In the test mode of operation, device  10  may send wireless test data to base stations  80  and/or may receive wireless test data from base stations  80 . If desired, device  10  may receive voice data from base stations  80  in addition to or instead of test data from base stations  80  during the test mode. During the normal mode of operation, device  10  may receive data traffic and/or voice data from base stations  80  (e.g., based on the configuration of base stations  80 ). For example, software or test circuitry on base stations  80  and device  10  may perform wireless testing operations on the network, device, and/or base stations when enabled. The test circuitry or software may be enabled autonomously (e.g., at a predetermined interval) and/or when selected by a user of the base station (e.g., when a network operator chooses to perform testing) or a user of the device (e.g., when an end user of the device chooses to perform testing). If desired, device connection settings may be cloned between base stations only when device  10  is operated in the test mode, only when operated in the normal communications mode, and/or in both the test mode and the normal communications mode. 
     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: 20150528
Publication Date: 20170704
Grant Date: 20170704
Priority Date: 20140613
Inventors: LUONG ANH Q.
Assignee: APPLE INC
CPC Classifications: [{"code": "H04W72/27", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04W72/27", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04W72/27", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04W72/27", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04W76/15", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04W76/15", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04W72/0453", "inventive": true, "first": true, "tree": "[]"}, {"code": "H04W76/15", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04W72/0453", "inventive": true, "first": true, "tree": "[]"}, {"code": "H04W72/0453", "inventive": true, "first": true, "tree": "[]"}, {"code": "H04L1/0003", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04W88/08", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04W72/0453", "inventive": true, "first": true, "tree": "[]"}, {"code": "H04L1/0003", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04W72/0426", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04W76/025", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04W72/0453", "inventive": true, "first": true, "tree": "[]"}, {"code": "H04W88/08", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04W76/15", "inventive": true, "first": true, "tree": "[]"}, {"code": "H04W72/27", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04W72/0453", "inventive": true, "first": false, "tree": "[]"}]
Family ID: 53434464