Patent Publication Number: US-2020280354-A1

Title: Method and Apparatus for Switching a Transmit Path of a Transceiver Between Three or More Antennas

Description:
FIELD OF THE APPLICATION 
     The present disclosure relates generally to controlling the transmit path of a wireless communication device, and more particularly, to selective coupling of the transceiver to one of multiple antennas in support of the transmission of a wireless radio frequency signal. 
     BACKGROUND 
     Wireless communication devices are continuously integrating new and enhanced features, that leverage an ability to remotely transmit and receive data using wireless communication capabilities. As the features are added and/or enhanced, there often is a need to communicate wirelessly, an ever increasing amount of information/data in order to support the added and/or enhanced features of the device. This need for additional data throughput impacts both the overall operation of the network, as well as the data throughput relative to individual devices operating within the network. 
     The overall desire for higher data throughput for at least some cellular networks has led to at least some networks implementing support for Multiple Input Multiple Output (MIMO) forms of communication, including for example 4×4 MIMO relative to one or more bands of operation, while simultaneously supporting carrier aggregation. MIMO is a method for expanding the capacity of a radio link using multiple transmit and receive antennas, where multipath propagation properties are used to distinguish between different sets of signaling sent simultaneously over the same radio channel via separate antennas. MIMO is distinct from other throughput enhancement techniques developed to augment the performance of a propagated data signal, such as a beamforming signal processing technique and/or a multiple antenna diversity scheme. Carrier aggregation allows a number of separate carriers to be combined into a single data channel to enhance the data rates and data throughput capacity relative to a particular user. 
     While many prior communication techniques combined the performance of a pair of antennas in support of a communication connection, a 4×4 MIMO technique expands this requirement for multiple antennas in support of a communication connection even further, so as to include at least four spatially distinct antennas. Such a requirement extends beyond the two spatially distinct antennas that supported prior signal diversity schemes. Correspondingly, some manufacturers have begun to integrate sets of antennas that incorporate individual respective antennas that each reside proximate a separate location around the device. For example, each of the four antennas can each separately reside proximate a corresponding one of the four corners of the device for use in receiving a 4×4 MIMO signal. In at least some instances, the device continues to transmit via a single transmit antenna. 
     However, it is possible that a particular one of the antennas assigned to transmit a signal can be at least temporarily compromised. For example, depending upon how a user is holding the device, the user&#39;s hand could come within proximity of one or more of the antennas. For example, in some instances, such as use in landscape mode, where multiple hands may be holding the device, it is possible for multiple antennas including antennas located at opposite sides of the device to be compromised. This can be particularly problematic, where the antennas are formed as part of an exterior metal housing. 
     When a user&#39;s hand encroaches upon and/or comes into contact with an antenna, for lower frequency signals, the hand can de-tune the antenna. In some of these cases, an antenna tuner can help to alleviate these concerns. However for higher frequency signal bands, the hand can absorb some of the energy, where an antenna tuner may be insufficient to fully recover from the corresponding adverse affects. 
     The present innovators have recognized that often there is an antenna among the various three or more spatially distinct antennas, that has not been compromised. Correspondingly by switching the transmit function to one of the uncompromised antennas, via a switch coupled to each of the three or more antennas, acceptable signal transmission performance may continue to be possible. 
     SUMMARY 
     The present application provides an antenna switching circuit. The antenna switching circuit includes three or more antennas, and a switch coupled to each of the three or more antennas. The antenna switching circuit further includes a controller coupled to the switch, as well as a transceiver, which is coupled to each of the three or more antennas via the switch. Each of the coupled antennas is selectively associated with a different respective receive path of the transceiver, and the transceiver has a transmitter path that can be separately selectively coupled to any one of the three or more antennas via the switch under the control of the controller. 
     In at least one embodiment, the antenna switching circuit further includes one or more sensors, which can be used to detect the conditions in which one or more of the three or more antennas are at least temporarily excluded from being coupled to the transmitter path of the transceiver by the controller. 
     In at least a further embodiment, the controller monitors, on an ongoing basis, the one or more sensors, and adjusts where appropriate an exclusion by the controller of any one of the three or more antennas from being coupled to the transmitter path of the transceiver. 
     The present application further provides a method for switching a transmit path of a transceiver between three or more antennas. The method includes evaluating signal propagation characteristics for each propagation path respectively associated with conveying a signal between each of the three or more antennas and a separate remote communication partner. A selection is then made by a controller via a switch of a particular one of the three or more antennas to couple to the transmit path of the transceiver. 
     The present invention still further provides a wireless communication device. The wireless communication device includes an antenna switching circuit having three or more antennas, a switch coupled to each of the three or more antennas, and a controller coupled to the switch. The wireless communication device further includes a transceiver, which is coupled to each of the three or more antennas via the switch, where each of the coupled antennas is selectively associated with a different respective receive path of the transceiver, and wherein the transceiver has a transmitter path that can be separately selectively coupled to any one of the three or more antennas via the switch under the control of the controller. 
     These and other features, and advantages of the present disclosure are evident from the following description of one or more preferred embodiments, with reference to the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a block diagram of an exemplary network environment; 
         FIG. 2  is a front view of an exemplary user equipment in the form of a wireless communication device, such as a radio frequency radio telephone; 
         FIG. 3  is an example of a user holding an exemplary device in portrait mode; 
         FIG. 4  is an example of a user holding an exemplary device in landscape mode; 
         FIG. 5  is a block diagram of an exemplary wireless communication device; 
         FIG. 6  is a block diagram of a radio frequency front end circuit for coupling a transceiver having a transmit line and one or more receive lines to a plurality of antennas; and 
         FIG. 7  is a flow diagram of a method for switching a transmit path of a transceiver between three or more antennas. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT(S) 
     While the present invention is susceptible of embodiment in various forms, there is shown in the drawings and will hereinafter be described presently preferred embodiments with the understanding that the present disclosure is to be considered an exemplification and is not intended to limit the invention to the specific embodiments illustrated. One skilled in the art will hopefully appreciate that the elements in the drawings are illustrated for simplicity and clarity and have not necessarily been drawn to scale. For example, the dimensions of some of the elements in the drawings may be exaggerated relative to other elements with the intent to help improve understanding of the aspects of the embodiments being illustrated and described. 
       FIG. 1  illustrates a block diagram of an exemplary network environment  100 . The exemplary network environment  100  can include one or more wireless communication devices, such as user equipment  102 , which might communicate directly with one another, or via one or more networks, each having an associated network infrastructure. For example, the network infrastructure can include one or more base stations  104 , which in turn are coupled to other network elements, which correspond to one or more networks, and which are generally represented as clouds labeled network  106 . The various base stations  104  can be associated with the same network or can be separately associated with different networks. 
     A base station  104  will generally have an expected associated area  108  of coverage, which defines the area over which wireless radio frequency signaling from the base station can generally reach. While the strength of wireless radio frequency signaling is generally affected by the range of transmission, within an expected area of coverage, terrain and/or other physical elements can impact the ability of the signaling to be perceived at particular locations within the expected area  108  of coverage. Depending upon the reception capabilities of the user equipment  102 , the current signal strength of the signal being transmitted at a particular location will affect whether a particular user equipment  102  can send or receive data with a particular base station  104 . As such, some networks  106  will make use of multiple geographically spaced apart base stations  104 , to provide communication capabilities across a larger geographical area. 
     It is further possible that different base stations  104  can be more directly associated with different networks  106 , which may interact with one another at different parts of the respective networks. The network(s)  106  can include any type of network that is capable of conveying signals between different associated elements of the network including the one or more user equipment  102 . 
     In some instances, the user equipment  102  is generally a wireless communication device that could take the form of a radio frequency cellular telephone. However, the user equipment  102  could also take the form of other types of devices that could support wireless communication capabilities. For example, the different potential types of user equipment can include a tablet, a laptop computer, a desktop computer, a netbook, a cordless telephone, a selective call receiver, a gaming device, a personal digital assistant, as well as any other type of wireless communication device that might be used to support wireless forms of communication. 
     The various networks  106 , base stations  104  and user equipment  102  could be associated with one or more different communication standards. A few examples of different communication standards that a particular network  106  could support include Global System for Mobile Communications (GSM) Code Division Multiple Access (CDMA), Orthogonal Frequency Division Multiple Access (OFDMA), Long Term Evolution (LTE), New Radio Access Technology (NR), Global Positioning System (GPS), Wi-Fi (IEEE 802.11), as well as various other communication standards. It is possible that each network and/or associated element could support one or more different communication standards. It is also possible that different networks  106  can support one or more of the same standards. In addition, the wireless communication devices  102 , base stations  104  and networks  106  may utilize a number of additional various forms of communication and communication techniques including beamforming, signal diversity, and simultaneous voice and data that concurrently enables the use of simultaneous signal propagation. 
       FIG. 2  illustrates a front view  200  of an exemplary user equipment  102  in the form of a wireless communication device, such as a radio frequency radio telephone. In the illustrated embodiment, the radio frequency cellular telephone includes a display  202  which covers a large portion of the front facing. In at least some instances, the display can incorporate a touch sensitive matrix, that can help facilitate the detection of one or more user inputs relative to at least some portions of the display, including an interaction with visual elements being presented to the user via the display  202 . In some instances, the visual elements could include an object with which the user can interact. In other instances, the visual elements can form part of a visual representation of a keyboard including one or more virtual keys and/or one or more buttons with which the user can interact and/or select for a simulated actuation. In addition to one or more virtual user actuatable buttons or keys, the device can include one or more physical user actuatable buttons  204 . In the particular embodiment illustrated, the device has three such buttons located along the right side of the device. 
     The exemplary electronic device, illustrated in  FIG. 2 , additionally includes a speaker  206  and a microphone  208  in support of voice communications. The speaker  206  may additionally support the reproduction of an audio signal, which could be a stand-alone signal, such as for use in the playing of music, or can be part of a multimedia presentation, such as for use in the playing of a movie, which might have at least an audio as well as a visual component. The speaker  206  may also include the capability to also produce a vibratory effect. However, in some instances, the purposeful production of vibrational effects may be associated with a separate element, not shown, which is internal to the device. Generally, the speaker  206  is located toward the top of the device, which corresponds to an orientation consistent with the respective portion of the device facing in an upward direction during usage in a portrait orientation in support of a voice communication. In such an instance, the speaker  206  might be intended to align with the ear of the user, and the microphone  208  might be intended to align with the mouth of the user. Also located near the top of the device, in the illustrated embodiment, is a front facing camera  210 . The wireless communication device will also generally include one or more radio frequency transceivers, as well as associated transmit and receive circuitry, including one or more antennas that may be positioned internally relative to the device. In some instances, some or all of the antenna elements may also and/or alternatively be incorporated as part of the housing of the device. 
       FIG. 3  illustrates an exemplary perspective view  300  of a user holding an exemplary device  102  in a portrait use mode or orientation. More specifically, the exemplary device  102  is being held by the hand  304  of a user. Depending upon their location, relative to the device  102 , the hand may come into contact and/or proximity to at least some of one or more antennas. As the hand  304  or other element approaches an antenna element, the hand  304  or other element may have an adverse effect on the ability of the antenna to receive or radiate energy, as intended. In some cases, the element coming into contact or proximity with an antenna can cause a detuning of the same. In other instances, the element coming into contact or proximity with an antenna can block or absorb nearby electromagnetic energy being produced by the antenna, and/or intended to be received via the antenna. In a portrait orientation, the device  102  can be more readily brought into proximity of the mouth and ear of the user, so as to more readily facilitate the receipt and conveyance of an audio signal, relative to a microphone and a speaker. However, in turn, this results in the head of the user being additionally brought into relative proximity to the device  102 , and potentially one or more of the antennas. 
     A user, however, can interact with a communication device  102  in multiple different ways. For example, a device  102  could be alternatively tilted and held using two hands  404 , which could change the portions of the device with which a user&#39;s hand  404  might encroach.  FIG. 4  illustrates an alternative examplary perspective view  400  of a user holding an exemplary device  102  in a landscape use mode or orientation. 
     In at least some instances, various antennas can be positioned so as to correspond with different spatially distinct locations around the device. In some of these instances, various antennas can be respectively located proximate different corners of a device. Depending upon how the device is being held, one or more of the antennas may come into proximity to one of the hands of the user. 
       FIG. 5  illustrates a block diagram  500  of an exemplary wireless communication device, in accordance with at least one embodiment. In the illustrated embodiment, the wireless communication device includes a controller  502 , which is adapted for managing at least some of the operation of the device. In some embodiments, the controller  502  could be implemented in the form of one or more processors  503 , which are adapted to execute one or more sets of pre-stored instructions  504 , which may be used to form or implement the operation of at least part of one or more controller modules including those used to manage wireless communication and/or the coupling of wireless communication signals to one or more antennas. The one or more sets of pre-stored instructions  504  may be stored in a storage element  506 , which while shown as being separate from and coupled to the controller  502 , may additionally or alternatively include some data storage capability for storing at least some of the prestored instructions for use with the controller  502 , that is integrated as part of the controller  502 . 
     The storage element  506  could include one or more forms of volatile and/or non-volatile memory, including conventional ROM, EPROM, RAM, or EEPROM. The possible additional data storage capabilities may also include one or more forms of auxiliary storage, which is either fixed or removable, such as a hard drive, a floppy drive, or a memory card or stick. One skilled in the art will still further appreciate that still other further forms of storage elements could be used without departing from the teachings of the present disclosure. In the same or other instances, the controller  502  may additionally or alternatively incorporate state machines and/or logic circuitry, which can be used to implement at least partially, some of the modules and/or functionality associated with the controller  502  including all or portions of the claimed methods. 
     In the illustrated embodiment, the device further includes a transceiver  508 , which is coupled to the controller  502  and which serves to manage the external communication of data including their wireless communication using one or more forms of communications. In such an instance, the transceiver  508  will generally be coupled to one or more antennas  510 , via which the wireless communication signals will be radiated and received. For example, the transceiver  508  might include one or more transceiver, transmitter, and/or receiver sub-elements  512  for supporting wireless communications with various networks. Transceivers, receivers and/or transmitters for other forms of communication are additionally and/or alternatively possible. In the present instance, the transceiver  508  is coupled to the one or more antennas  510  via front end circuitry  513  and an N-pole, N-throw switch  511 , which can help to facilitate the transceiver  508 , and the various transmit and receive paths supported within the transceiver  508  interacting with various respective ones of the one or more antennas  510 . 
     More specifically, the front end circuitry  513  and N-pole, N-throw switch  511  are intended to allow one or more transceiver ports to be selectively coupled to one or more ports associated with the various antenna elements. Front end circuitry can often include various sub-elements, such as power amplifiers, filters, diplexers, duplexers and switches, which help to facilitate the coupling of a produced signal to an antenna. The front end circuitry  513  can further include impedance matching elements, antenna tuners, and/or additional signal amplifiers, so as to more effectively manage the conveyance of signals between the transceivers and the antenna elements. 
     In the illustrated embodiment, the device can additionally include user interface circuitry  515 , some of which can be associated with producing an output  516  to be perceived by the user, and some of which can be associated with detecting an input  518  from the user. For example, the user interface circuitry  515  can include a display  202  adapted for producing a visually perceptible output, which may further support a touch sensitive array for receiving an input from the user. The user interface circuitry may also include a speaker  206  for producing an audio output, and a microphone  208  for receiving an audio input. The user interface output  515  could further include a vibrational element. The user interface input  518  could further include one or more user actuatable switches  204 , as well as one or more cameras  210 . Still further alternative and additional forms of user interface elements may be possible. 
     In the illustrated embodiment, the device can still further include one or more sensors  520 , which can be used for gathering status information relative to the operating environment as well as the manner in which the device is being used. For example, the one or more sensors  520  can include one or more of tilt sensors  522  and/or proximity sensors  524 , which the device can use to detect the usage orientation, as well as the presence of nearby elements proximate the corresponding sensors. In turn, this information can be used to help determine how other elements of the device are controlled including to which ones of the antenna elements  510  a transmit path of the transceiver  508  might be coupled. 
       FIG. 6  illustrates a partial block diagram  600  of a radio frequency front end circuit for coupling a transceiver having a transmit path and one or more receive paths to a plurality of antennas. More specifically, the partial block diagram  600  of front end circuitry includes a power amplifier  614 , which has an input  622 , which is adapted for receiving a radio frequency transmit signal from a transceiver sub-element  612  of the transceiver  608 , and has an output  624 , which is adapted for producing an amplified radio frequency signal. The amplified radio frequency signal of the transmit path of the transceiver sub-element  612  is grouped with a corresponding receive path signal via a duplexer  626 . The grouped signal is coupled to the input port of the 4-pole, 4-throw switch that can be selectively coupled to a respective one of each of the 4 output ports of the switch  611 . The other three input ports of the switch are coupled to a respective receiver sub element of the transceiver  611  via a respective receive filter  628 . 
     In turn, each of the output ports of the switch  611  is coupled to an antenna element  610  via an antenna tuner  630 . In at least some instances, the antenna tuner  630  can compensate for at least some detuning of the antenna due to external factors, such as the contact and/or proximity of an external element relative to the corresponding antenna element  610  for signals having at least some frequencies, i.e. typically relatively lower radio frequency signals. Alternatively, the 4-pole, 4-throw switch  611  can be used to reroute the transmit path associated with the transmitter sub-element  612  away from antennas  610  that are deemed to be adversely affected by external factors. While an antenna is deemed to be adversely affected, the antenna can be excluded from being used with the corresponding transceiver  608  sub element having a transmit path. 
     In some cases, the determination of an antenna  610  being adversely affected can be determined through an analysis by the controller  502  of the readings of the one or more sensors  520 . In other instances, the controller  502  can rely upon feedback signaling received from the intended destination, such as a network base station  104 , to determine the extent that a particular antenna might be being affected. For example, a closed loop feedback path could be evaluated including a received signal strength indicator (RSSI) for each of the antenna elements  610  could be evaluated, and the element  610  producing the strongest signal at the intended destination could be selected. Such a check could be performed periodically to account for the possibility of changing circumstances. The output of the sensors might be monitored to control how frequently the closed loop feedback is checked. 
     The transceiver sub elements (receiver sub-elements  611  and transceiver sub-element  612  can each be coupled to one or more modems. The one or more modems can each be implemented as part of at least one of the one or more processors  503  of the controller  502 . The controller/modem can further provide various control signaling which in turn can affect the performance of the duplexers  626  and receive filters  628 , as well as the antenna tuner  630 . The controller/modem can still further provide the control signal used by the 4-pole, 4-throw switch  611  to determine to which one of the antenna elements  610  the transmit path is to be currently coupled. 
     By taking advantage of the increase in the number of antenna elements that are included in support of enhanced signaling techniques, such as 4×4 MIMO, the instances in which a transmit path can be negatively affected by the manner in which the device is being used can be reduced. In turn this can improve transmitter functionality without necessarily resorting to increases in transmitter power, by routing transmit signal paths to antenna elements that are less likely to be experiencing current degradations in performance. 
       FIG. 7  illustrates a flow diagram  700  of a method for switching a transmit path of a transceiver between three or more antennas. The method  700  includes evaluating  702  signal propagation characteristics for each propagation path respectively associated with conveying a signal between each of the three or more antennas and a separate remote communication partner. A particular one of the three or more antennas is selected  704  by a controller to couple to the transmit path of the transceiver via a switch. 
     In some instances, the evaluation of the signal propagation characteristics are at least periodically repeated  706 . When the propagation characteristics have changed, the particular one of the three or more antennas that is coupled to the transmit path of the transceiver is updated  708 , where appropriate. In some instances, selecting by the controller includes a selection for coupling of the particular one of the three or more antennas, that is respectively associated with the propagation path having the smallest path losses. 
     While the preferred embodiments have been illustrated and described, it is to be understood that the invention is not so limited. Numerous modifications, changes, variations, substitutions and equivalents will occur to those skilled in the art without departing from the spirit and scope of the present invention as defined by the appended claims.