PATENT DOCUMENT

Publication Number: US-10680693-B1
Application Number: US-201916379377-A
Country: US
Kind Code: B1

Title: Radio frequency beamforming calibration systems and methods

Abstract:
Systems and methods for improving testing and/or calibration efficiency of radio frequency system. In some embodiments, a testing system includes a beamformer radio frequency system, in which the beamformer radio frequency system includes first transceiver circuitry and a first plurality of antennas coupled to the first transceiver circuitry, a beamformee radio frequency system, in which the beamformee radio frequency system includes second transceiver circuitry and a second plurality of antennas coupled to the second transceiver circuitry, one or more wired connections coupled between the first transceiver circuitry of the beamformer radio frequency system and the second transceiver circuitry of the beamformee radio frequency system, in which each of the one or more wired connections bypasses the first plurality of antennas of the first radio frequency system and the second plurality of antennas of the second radio frequency system.

Claims:
What is claimed is: 
     
       1. A testing system comprising:
 a beamformer radio frequency system, wherein the beamformer radio frequency system comprises first transceiver circuitry and a first plurality of antennas coupled to the first transceiver circuitry; 
 a beamformee radio frequency system, wherein the beamformee radio frequency system comprises second transceiver circuitry and a second plurality of antennas coupled to the second transceiver circuitry; and 
 one or more wired connections coupled between the first transceiver circuitry of the beamformer radio frequency system and the second transceiver circuitry of the beamformee radio frequency system, wherein each of the one or more wired connections bypasses the first plurality of antennas of the beamformer radio frequency system and the second plurality of antennas of the beamformee radio frequency system, and wherein the one or more wired connections transmit beamforming parameters between the beamformer radio frequency system and the beamformee radio frequency system. 
 
     
     
       2. The testing system of  claim 1 , wherein:
 the beamformer radio frequency system is configured to not transmit electromagnetic waves from the first plurality of antennas during a testing process; and 
 the first transceiver circuitry of the beamformer radio frequency system is configured to transmit one or more analog electrical signals corresponding to a test data packet to the second transceiver circuitry of the beamformee radio frequency system via the one or more wired connections during the testing process. 
 
     
     
       3. The testing system of  claim 1 , wherein:
 the beamformee radio frequency system is configured to not transmit electromagnetic waves from the second plurality of antennas during a testing process; and 
 the second transceiver circuitry of the beamformee radio frequency system is configured to transmit the beamforming parameters to be used by the beamformer radio frequency system to transmit a subsequent data packet via the one or more wired connections during the testing process. 
 
     
     
       4. The testing system of  claim 1 , wherein the beamformer radio frequency system is configured to process a packet before transmission to the beamformee radio frequency system via the one or more wired connections to emulate an expected effect of transmitting the packet via a wireless communication channel without transmitting the packet via the wireless communication channel. 
     
     
       5. The testing system of  claim 1 , wherein the beamformer radio frequency system is configured to:
 determine channel emulation parameters that emulate wireless transmission from the beamformer radio frequency to the beamformee radio frequency system via a wireless communication channel; 
 generate a plurality of modified versions of a beamforming initiation packet at least in part by adjusting phase, magnitude, or both of the beamforming initiation packet based at least in part on the channel emulation parameters; and 
 transmit one or more of analog electrical signals indicative of the plurality of modified versions of the beamforming initiation packet to the beamformee radio frequency system via the one or more wired connections. 
 
     
     
       6. The testing system of  claim 5 , wherein the beamformee radio frequency system is configured to:
 determine the plurality of modified versions of the beamforming initiation packet based at least in part on the one or more analog electrical signals received via the one or more wired connections; 
 determine a current set of communication conditions based at least in part on distortion introduced in one or more of the plurality of modified versions of the beamforming initiation packet; and 
 determine the beamforming parameters to be used by the beamformer radio frequency system to process a subsequent data packet based at least in part on the current set of communication conditions. 
 
     
     
       7. The testing system of  claim 1 , wherein the beamformer radio frequency system is configured to:
 receive the beamforming parameters transmitted from the beamformee radio frequency system via the one or more wired connections; 
 determine channel emulation parameters that emulate wireless transmission from the beamformer radio frequency system to the beamformee radio frequency system via a wireless communication channel; 
 generate a first plurality of modified versions of a first data packet at least in part by adjusting phase, magnitude, or both of the first data packet based at least in part on the beamforming parameters and the channel emulation parameters; and 
 transmit one or more of analog electrical signals indicative of the first plurality of modified versions of the first data packet to the beamformee radio frequency system via the one or more wired connections. 
 
     
     
       8. The testing system of  claim 7 , wherein:
 the beamformee radio frequency system is configured to determine the first plurality of modified versions of the first data packet based at least in part on the one or more analog electrical signals received from the beamformer radio frequency system via the one or more wired connections; and 
 the testing system is configured to determine a data packet error rate based at least in part on one or more comparisons between different versions of the first data packet. 
 
     
     
       9. The testing system of  claim 8 , wherein the testing system is configured to:
 determine whether the data packet error rate is greater than an error threshold; 
 maintain a current configuration of the beamformee radio frequency system when the data packet error rate is not greater than the error threshold; and 
 adjust the current configuration of the beamformee radio frequency system when the data packet error rate is greater than the error threshold. 
 
     
     
       10. The testing system of  claim 7 , wherein:
 the beamformer radio frequency system is configured to generate a second plurality of modified versions of a second data packet to be concurrently transmitted with the first data packet at least in part by adjusting phase, magnitude, or both of the second data packet based at least in part on the beamforming parameters and the channel emulation parameters; and 
 the one or more of analog electrical signals transmitted from the beamformer radio frequency system to the beamformee radio frequency system via the one or more wired connections are indicative of the first plurality of modified versions of the first data packet and the second plurality of modified versions of the second data packet. 
 
     
     
       11. The testing system of  claim 10 , wherein the beamformee radio frequency system is configured to:
 the beamformee radio frequency system is configured to determine the second plurality of modified versions of the second data packet based at least in part on the one or more analog electrical signals received from the beamformer radio frequency system via the one or more wired connections; and 
 the testing system is configured to determine a data packet error rate based at least in part on one or more comparisons between different versions of the second data packet. 
 
     
     
       12. The testing system of  claim 1 , comprising a first electronic device and a second electronic device, wherein:
 the beamformer radio frequency system is deployed in the first electronic device; 
 the first electronic device comprises a first computer, a first mobile phone, a first portable media device, a first tablet device, a first television, a first handheld game platform, a first personal data organizer, a first virtual-reality headset, a first mixed-reality headset, or a first vehicle dashboard; 
 the beamformee radio frequency system is deployed in the second electronic device; and 
 the second electronic device comprises a second computer, a second mobile phone, a second portable media device, a second tablet device, a second television, a second handheld game platform, a second personal data organizer, a second virtual-reality headset, a second mixed-reality headset, or a second vehicle dashboard. 
 
     
     
       13. A method of operating a testing system comprising:
 receiving, using a first radio frequency system in the testing system, a first analog electrical signal transmitted from a second radio frequency system via a first wired connection coupled between the first radio frequency system and the second radio frequency system, wherein the first analog electrical signal comprises a first modified version of a beamforming initiation packet modified by the first radio frequency system at least in part to emulate wireless transmission of the beamforming initiation packet from the second radio frequency system to the first radio frequency system via a wireless communication channel; 
 determining, using the first radio frequency system, beamforming parameters to be used by the second radio frequency system to process one or more subsequent data packets based at least in part on a current configuration of the first radio frequency system and one or more comparisons between different versions of the beamforming initiation packet; and 
 transmit, using transceiver circuitry of the first radio frequency systems, the beamforming parameters to the second radio frequency system via the first wired connection or a dedicated wired connection coupled between the first radio frequency system and the second radio frequency system. 
 
     
     
       14. The method of  claim 13 , comprising:
 receiving, using the first radio frequency system, a second analog electrical signal transmitted from the second radio frequency system via the first wired connection, wherein the second analog electrical signal comprises a first version of a first data packet modified by the first radio frequency system based at least in part on the beamforming parameters and channel emulation parameters that emulate wireless transmission from the second radio frequency system to the first radio frequency system via the wireless communication channel; 
 determining, using the testing system, a packet error rate based at least in part on one or more comparisons between different versions of the first data packet; and 
 adjusting, using the testing system, the current configuration of the first radio frequency system when the packet error rate is greater than an error threshold. 
 
     
     
       15. The method of  claim 14 , comprising:
 generating, using the second radio frequency system, the first modified version of the beamforming initiation packet at least in part by adjusting phase, magnitude, or both of an original version of the beamforming initiation packet based at least in part on the channel emulation parameters; and 
 generating, using the second radio frequency system, the first version of the first data packet at least in part by adjusting phase, magnitude, or both of the first data packet based at least in part on the beamforming parameters and the channel emulation parameters. 
 
     
     
       16. The method of  claim 14 , comprising determining the packet error rate based at least in part on one or more comparisons between different versions of a second data packet transmitted from the second radio frequency system concurrently with the first data packet, wherein the second analog electrical signal comprises a second version of the second data packet modified by the first radio frequency system based at least in part on the beamforming parameters and the channel emulation parameters. 
     
     
       17. The method of  claim 14 , comprising:
 receiving, using the first radio frequency system, a third analog electrical signal transmitted from the second radio frequency system via a second wired connection, wherein the third analog electrical signal comprises a second version of the first data packet modified by the first radio frequency system based at least in part on the beamforming parameters and the channel emulation parameters; and 
 determining, using the testing system, the packet error rate based at least in part on a first comparison between the first version of the first packet and the second version of the first data packet, a second comparison between the first version of the first data packet and an original version of the first data packet, a third comparison between the second version of the first data packet and the original version of the first data packet, or any combination thereof. 
 
     
     
       18. The method of  claim 13 , comprising:
 receiving, using the first radio frequency system, a second analog electrical signal transmitted from the second radio frequency system via a second wired connection coupled between the first radio frequency system and the second radio frequency system, wherein the second analog electrical signal comprises a second modified version of the beamforming initiation packet modified by the first radio frequency system at least in part to emulate wireless transmission from the second radio frequency system to the first radio frequency system via the wireless communication channel; and 
 determining, using the first radio frequency system, the beamforming parameters to be used by the second radio frequency system to process one or more subsequent data packets based at least in part on a first comparison between the first modified version of the beamforming initiation packet and the second modified version of the beamforming initiation packet, a second comparison between the first modified version of the beamforming initiation packet and an original version of the beamforming initiation packet, a third comparison between the second modified version of the beamforming initiation packet and the original version of the beamforming initiation packet, or any combination thereof. 
 
     
     
       19. An electronic device comprising a first radio frequency system, comprising:
 memory configured to store channel emulation parameters that emulate an expected effect of wireless communication between the first radio frequency system and a second radio frequency system via a wireless communication channel; and 
 transceiver circuitry configured to, during testing of the first radio frequency system: 
 adjust magnitude, phase, or both of a first packet based at least in part on the channel emulation parameters to determine a first plurality of versions of the first packet; and 
 output a first one or more analog electrical signals indicative of the first plurality of versions of the first packet to one or more wired connections coupled to the transceiver circuitry to enable communication of the first plurality of versions of the first packet to the second radio frequency system without using the wireless communication channel. 
 
     
     
       20. The electronic device of  claim 19 , wherein:
 the first radio frequency system comprises a plurality of antennas coupled to the transceiver circuitry; and 
 the transceiver circuitry is configured to, during normal operation, use the first one or more analog electrical signals to the plurality of antennas to enable the first radio frequency system to wirelessly transmit a second packet using one or more electromagnetic wave beams. 
 
     
     
       21. The electronic device of  claim 19 , wherein:
 the first packet comprises a beamforming initiation packet; and 
 the transceiver circuitry is configured to, during testing of the first radio frequency system:
 receive beamforming parameters returned via the one or more wired connections in response to transmission of the beamforming initiation packet; 
 adjust magnitude, phase, or both of a data packet based at least in part on the beamforming parameters and the channel emulation parameters to determine a second plurality of versions of the data packet; and 
 output a second one or more analog electrical signals indicative of the second plurality of versions of the data packet to the one or more wired connections to enable communication of the second plurality of versions of the data packet to the second radio frequency system without using the wireless communication channel. 
 
 
     
     
       22. The electronic device of  claim 19 , wherein:
 the first packet comprises a first data packet; and 
 the transceiver circuitry is configured to, during testing of the first radio frequency system:
 receive beamforming parameters returned via the one or more wired connections in response to transmission of a beamforming initiation packet from the first radio frequency system; 
 adjust magnitude, phase, or both of the first data packet based at least in part on the beamforming parameters and the channel emulation parameters to determine a second plurality of versions of the first data packet; 
 adjust magnitude, phase, or both of a second data packet to be transmitted from the first radio frequency system concurrently with the first data packet based at least in part on the beamforming parameters and the channel emulation parameters to determine a third plurality of versions of the second data packet; and 
 output a second one or more analog electrical signals indicative of the second plurality of versions of the first data packet and the third plurality of versions of the second data packet to the one or more wired connections to enable communication to the second radio frequency system without using the wireless communication channel.

Description:
BACKGROUND 
     The present disclosure generally relates to radio frequency systems and, more particularly, to calibration and/or testing of beamforming (e.g., beamsteering) techniques implemented in a radio frequency system. 
     This section is intended to introduce the reader to various aspects of art that may be related to various aspects of the present techniques, which are described and/or claimed below. This discussion is believed to be helpful in providing the reader with background information to facilitate a better understanding of the various aspects of the present disclosure. Accordingly, it should be understood that these statements are to be read in this light, and not as admissions of prior art. 
     Electronic devices often include a radio frequency system to facilitate wireless data communication with another electronic device and/or a communication network, such as a Wi-Fi network and/or a cellular network. Generally, a radio frequency system may include transceiver circuitry and an antenna, which is coupled to the transceiver circuitry. To facilitate wirelessly transmitting data, the transceiver circuitry may generate an analog representation of the data as an analog electrical signal and the antenna may modulate electromagnetic (e.g., radio) waves based at least in part on the analog electrical signal. Additionally or alternatively, the antenna may output an analog representation of received (e.g., incident) electromagnetic waves as an analog electrical signal and the transceiver circuitry may process the analog electrical signal, for example, to convert the analog electrical signal into a digital electrical signal to facilitate subsequent processing. 
     However, wireless communication between radio frequency systems is generally affected by communication conditions, such as propogation loss resulting between the radio frequency systems and/or presence of stray electromagnetic waves, which potentially vary. In fact, in some instances, a radio frequency system may adaptively adjust operation based at least in part on current communication conditions, for example, to facilitate balancing operational efficiency (e.g., power consumption) and communication reliability (e.g., communication distance and/or signal strength). To facilitate adaptive operation adjustment, in some instances, operation of a radio frequency system may be tested and/or calibrated under various communication conditions, for example, which are expected to occur during normal operation of the radio frequency system after deployment of an electronic device including the radio frequency system. 
     In other words, in some instances, a radio frequency system may be tested and/or calibrated by reproducing various sets of communication conditions (e.g., channel configurations) and operating the radio frequency system under the reproduced communication conditions. However, at least in some instances, reproducing a set of communication conditions may be a complex and/or time consuming process, for example, due to the set of communication conditions being physically reproducing using heavy equipment and/or an anechoic room. In other words, efficiency with which communication conditions may be reproduced may affect testing and/or calibration efficiency of a radio frequency system and, thus, an electronic device in which the radio frequency system is deployed. 
     SUMMARY 
     A summary of certain embodiments disclosed herein is set forth below. It should be understood that these aspects are presented merely to provide the reader with a brief summary of these certain embodiments and that these aspects are not intended to limit the scope of this disclosure. Indeed, this disclosure may encompass a variety of aspects that may not be set forth below. 
     The present disclosure generally relates to radio frequency systems, which may be implemented in electronic devices to facilitate wireless communication (e.g., transmission and/or reception). At least in some instances, different communication networks and/or different radio frequency systems may utilize different communication protocols and/or different communication frequencies. 
     Nevertheless, radio frequency systems generally include transceiver (e.g., transmitter and/or receiver) circuitry and at least one antenna and, thus, operation of radio frequency systems may generally be similar. For example, to facilitate wirelessly transmitting data, the transceiver circuitry may generate an analog representation of the data as an analog electrical signal and the antenna may modulate electromagnetic (e.g., radio) waves based at least in part on the analog electrical signal. Additionally or alternatively, the antenna may output an analog representation of received (e.g., incident) electromagnetic waves as an analog electrical signal and the transceiver circuitry may process the analog electrical signal, for example, to convert the analog electrical signal into a digital electrical signal. 
     To facilitate improving operational efficiency and/or communication reliability, in some instances, radio frequency systems may be implemented with multiple antennas. In particular, in some instances, a (e.g., receiving or beamformee) radio frequency system may include an array of multiple antennas to enable the radio frequency system to receive multiple concurrently transmitted data streams, for example, using beamforming techniques. Additionally or alternatively, a (e.g., transmitting or beamformer) radio frequency system may include an array of multiple antennas to enable the radio frequency system to wirelessly transmit one or more data streams using beamforming techniques. 
     To implement beamforming techniques, a beamformer (e.g., transmitting) radio frequency system may concurrently transmit electromagnetic wave signals from multiple antennas such that additive and/or destructive interference therebetween produces one or more electromagnetic wave beams (e.g., concentrated strength) oriented in a target direction, such as toward a target beamformee (e.g., receiving) radio frequency system. In fact, at least in some instances, orientation of an electromagnetic wave beam produced by a beamformer radio frequency system may be adjusted by adaptively controlling phase and/or magnitude of analog electrical signals supplied to its antennas. In other words, at least in some instances, coding (e.g., beamforming) parameters to be used by a beamformer radio frequency system and/or a beamformee radio frequency system to implement beamforming techniques may be dependent at least in part on communication conditions, such as location (e.g., distance and/or orientation) of the beamformee radio frequency system relative to the beamformer radio frequency system. 
     However, communication conditions often vary, for example, due to a radio frequency system being moved and/or the radio frequency system communicating with different radio frequency systems at different times. To facilitate accounting for potential variations, in some instances, a target beamformee radio frequency system may determine current communication conditions, for example, based at least in part on distortion introduced on a beamforming initiation packet, such as a non-data packet (NDP), received from a beamformer radio frequency system. Additionally, based at least in part on the current communication conditions, the target beamformee radio frequency system may determine coding (e.g., encoding and/or decoding) parameters and return encoding (e.g., beamforming) parameters to the beamformer radio frequency system. 
     In this manner, the beamformer radio frequency system may process subsequent data packets based at least in part on the encoding parameters to facilitate wirelessly transmitting the data packets via one or more electromagnetic wave beams. Additionally or alternatively, the beamformee radio frequency system may process analog electrical signals output from its antennas and/or corresponding digital electrical signals based at least in part on decoding parameters to facilitate identifying the data packets. In other words, at least in some instances, coding (e.g., encoding and/or decoding) parameters determined for different sets of communication conditions may affect operational efficiency and/or communication reliability of radio frequency systems, for example, due to encoding parameters resulting in an electromagnetic wave beam oriented in an improper direction and/or a beamformer radio frequency system re-transmitting dropped packets. 
     Accordingly, to facilitate improving operational efficiency and/or communication reliability of radio frequency systems, the present disclosure provides techniques for implementing and/or operating a testing system to facilitate calibrating and/or testing performance (e.g., operation) of a radio frequency system under various sets of communication conditions. In some instances, a radio frequency system may be calibrated and/or tested by physically reproducing communication conditions and operating the radio frequency within the physically reproduced communication conditions. However, physically reproducing communication conditions is often a complex and/or time consuming process, which, at least in some instances, may limit calibration efficiency and/or testing efficiency of radio frequency systems, for example, due to a wireless communication channel being physically reproduced using heavy equipment and/or an anechoic room. 
     To facilitate improving calibration and/or testing efficiency, in some embodiments, a testing system may include a tester radio frequency system implemented and/or operated to emulate wireless communication, for example, on-chip. In some embodiments, a tester radio frequency system may emulate wireless communication by emulating the effect that transmission of a packet via a wireless communication channel is expected to have on the packet. In other words, before transmitting a packet, the tester radio frequency system may modify magnitude and/or phase of the packet based at least in part on distortion expected to be introduced due to wireless transmission of the packet. 
     In fact, in some embodiments, emulating wireless communication in this manner may enable calibration and/or testing of another (e.g., device under testing (DUT)) radio frequency system via one or more wired connections. For example, a testee radio frequency system may be wired to the tester radio frequency system in the testing system in a manner that bypasses their antennas. In other words, in such embodiments, transceiver circuitry of the tester radio frequency system may be coupled to to transceiver circuitry of the testee radio frequency system via one or more wired connections and, thus, an analog electrical signal received by the transceiver circuitry of the testee radio frequency system may emulate transmission of one or more corresponding packets from the tester radio frequency system to the testee radio frequency system via a wireless communication channel. 
     As such, during a testing (e.g., calibration) process, a tester radio frequency system may operate similarly to a beamformer radio frequency system. However, during the testing process, the tester radio frequency system may process the beamforming initiation packet based on encoding parameters, which emulate the effect of communication conditions currently being tested, and output analog electrical signals indicative of the encoded packet to the testee radio frequency system via one or more wired connections. In other words, during the testing process, the set of encoding parameters applied by the tester radio frequency system may include channel emulation parameters and/or beamforming parameters. In particular, the tester radio frequency system may process a beamforming initiation packet based on the channel emulation parameters, for example, along with default (e.g., uniform gain and/or uniform phase shift) beamforming parameters. Additionally, the tester radio frequency system may process subsequent data packets based on the channel emulation parameters as well as updated (e.g., non-default) beamforming parameters returned from the tested radio frequency system. 
     Additionally, during the testing process, a testee radio frequency system may operate similarly to a beamformee radio frequency. However, during the testing process, the testee radio frequency system may return a set of beamforming (e.g., encoding) parameters to the tester radio frequency system via one or more wired connections. Additionally, during the testing process, the testee radio frequency system may receive packets transmitted from a tester radio frequency system via one or more wired connections. 
     In some embodiments, a testing system may evaluate performance of a testee radio frequency system as a beamformee based at least in part on one or more comparisons between different versions of a packet. In fact, in some embodiments, one or more data packets to be transmitted during the testing process may be pre-determined and stored in a tangible, non-transitory, computer-readable medium of the testing system, for example, in controller memory. By comparing different versions of a data packet, the testee may determine distortion and, thus, a packet error rate resulting from transmission of the data packet to the testee radio frequency system. 
     To facilitate improving performance as a beamformee, in some embodiments, the testing system may adaptively adjust configuration (e.g., programming and/or implementation) of a testee radio frequency system during the testing (e.g., calibration) process. For example, the testing system may adjust a current configuration of the testee radio frequency system such that the testee radio frequency system determines a different set of beamforming parameters if a current set of communication conditions is subsequently determined again. Additionally, in some embodiments, the testing system may adjust the current configuration of the testee radio frequency system when use of the previously returned set of beamforming parameters result in a packet error rate greater than an error threshold. In fact, in some embodiments, operation (e.g., performance) of the testee radio frequency system under different sets of communication conditions may be tested and/or calibrated merely be adjusting the channel emulation parameters applied by the tester radio frequency system. In this manner, as will be described in more detail below, the techniques described in the present disclosure may facilitate improving calibration efficiency and/or testing efficiency of a radio frequency system and, thus, an electronic device in which the radio frequency system is deployed, for example, by obviating wireless communication and, thus, physical reproduction of communication conditions during testing and/or calibration of the radio frequency system. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Various aspects of the present disclosure may be better understood upon reading the following detailed description and upon reference to the drawings in which: 
         FIG. 1  is a block diagram of an electronic device including a radio frequency system, in accordance with an embodiment of the present disclosure; 
         FIG. 2  is an example of the electronic device of  FIG. 1 , in accordance with an embodiment; of the present disclosure 
         FIG. 3  is another example of the electronic device of  FIG. 1 , in accordance with an embodiment of the present disclosure; 
         FIG. 4  is another example of the electronic device of  FIG. 1 , in accordance with an embodiment of the present disclosure; 
         FIG. 5  is another example of the electronic device of  FIG. 1 , in accordance with an embodiment of the present disclosure; 
         FIG. 6  is block diagram of an example of the radio frequency system of  FIG. 1 , in accordance with an embodiment of the present disclosure; 
         FIG. 7  is a block diagram of an example of a wireless communication system including a transmitting (e.g., beamformer) radio frequency system and a receiving (e.g., beamformee) radio frequency system, in accordance with an embodiment of the present disclosure; 
         FIG. 8  is a flow diagram of an example process for operating the transmitting radio frequency system of  FIG. 7 , in accordance with an embodiment of the present disclosure; 
         FIG. 9  is a flow diagram of an example process for operating the receiving radio frequency system of  FIG. 7 , in accordance with an embodiment of the present disclosure; 
         FIG. 10  is block diagram of a testing system including a transmitting (e.g., tester) radio frequency system and a receiving (e.g., testee) radio frequency system, in accordance with an embodiment of the present disclosure; 
         FIG. 11  is a flow diagram of an example process for operating the transmitting radio frequency system of  FIG. 10  during a testing process, in accordance with an embodiment of the present disclosure; and 
         FIG. 12  is a flow diagram of an example process for operating the receiving radio frequency system of  FIG. 10  during the testing process, in accordance with an embodiment of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     One or more specific embodiments of the present disclosure will be described below. These described embodiments are only examples of the presently disclosed techniques. Additionally, in an effort to provide a concise description of these embodiments, all features of an actual implementation may not be described in the specification. It should be appreciated that in the development of any such actual implementation, as in any engineering or design project, numerous implementation-specific decisions must be made to achieve the developers&#39; specific goals, such as compliance with system-related and business-related constraints, which may vary from one implementation to another. Moreover, it should be appreciated that such a development effort might be complex and time consuming, but may nevertheless be a routine undertaking of design, fabrication, and manufacture for those of ordinary skill having the benefit of this disclosure. 
     When introducing elements of various embodiments of the present disclosure, the articles “a,” “an,” and “the” are intended to mean that there are one or more of the elements. The terms “comprising,” “including,” and “having” are intended to be inclusive and mean that there may be additional elements other than the listed elements. Additionally, it should be understood that references to “one embodiment” or “an embodiment” of the present disclosure are not intended to be interpreted as excluding the existence of additional embodiments that also incorporate the recited features. 
     The present disclosure generally relates to radio frequency systems, which may be implemented in electronic devices to facilitate wireless communication. For example, a radio frequency system may facilitate wireless communication between electronic devices. Additionally or alternatively, a radio frequency system may facilitate wireless communication between an electronic device and a communication network, such as a Bluetooth network, a Wi-Fi network, and/or a cellular (e.g., LTE, 5G, or millimeter wave) network. 
     Different types of communication networks often utilize different communication protocols and/or different communication (e.g., transmission and/or reception) frequencies. For example, a Wi-Fi network may utilize communication frequencies, such as a 900 MHz band, a 2.4 GHz band, a 3.6 GHz band, a 4.9 GHz band, a 5 GHz band, a 5.9 GHz band, and/or a 60 GHz band. As a further example, a millimeter wave (mmWave) communication network may utilize communication frequencies, such as a 28 GHz band, a 38 GHz band, and/or a 60 GHz band. 
     Nevertheless, radio frequency systems generally include transceiver (e.g., transmitter and/or receiver) circuitry and at least one antenna coupled to the transceiver circuitry. As such, operation of radio frequency systems may be generally similar. For example, to wirelessly transmit a (e.g., data) packet, transceiver circuitry of a first radio frequency system may determine a digital representation of the packet as a first digital electrical signal. Based at least in part on the first digital electrical signal, the transceiver circuitry may generate an analog representation of the packet as a first analog electrical signal. An antenna coupled to the transceiver circuitry may then may modulate electromagnetic (e.g., radio) waves based at least in part on the first analog electrical signal, thereby wirelessly transmitting the packet from the first radio frequency system via an electromagnetic wave signal. 
     On the other end, an antenna may output analog electrical signals based at least in part on received (e.g., incident) electromagnetic (e.g., radio) waves. In other words, when an electromagnetic wave signal corresponding with the (e.g., data) packet is incident on an antenna of a second radio frequency system, the antenna may output an analog representation of the packet to transceiver circuitry of the second radio frequency as a second analog electrical signal. Based on the second analog electrical signal, the transceiver circuitry may generate a digital representation of the packet as a second digital electrical signal, thereby receiving the wirelessly transmitted packet. 
     However, an electromagnetic wave generally experiences some amount of loss as it propagates, for example, which reduces power of the electromagnetic wave proportionally with travel (e.g., propagation) distance squared. Moreover, electromagnetic waves may generally interact with each other, thereby producing additive interference and/or destructive interference. However, in normal operating scenarios, stray electromagnetic waves are generally present, for example, due at least in part to persistent emission of electromagnetic waves from the Sun. In other words, continuing with the above example, the electromagnetic wave signal transmitted from the first radio frequency system may differ from the electromagnetic wave signal received by the second radio frequency system, which, at least in some instances, may affect communication reliability, for example, due to propogation loss and/or stray electromagnetic waves causing the transmitted version of the packet to differ from the version determined by the second radio frequency system. 
     To facilitate improving communication reliability, a radio frequency system may include amplifier circuitry that operates to amplify analog electrical signals, for example, before the analog electrical signals are used to transmit corresponding electromagnetic waves and/or before the analog electrical signals are converted into corresponding digital electrical signals. During operation, the amplifier circuitry may apply a gain to an input analog electrical signal to produce an output analog electrical signal with increased magnitude. In particular, increasing gain (e.g., amount of amplification) applied to an analog electrical signal before transmission may increase magnitude (e.g., output power) of resulting electromagnetic waves. In other words, increasing gain applied in a transmitting radio frequency system may facilitate compensating for propogation loss resulting in an electromagnetic wave signal transmitted from the transmitting radio frequency system to a receiving radio frequency system, which, at least in some instances, may facilitate improving ability of the receiving radio frequency system to properly identify a transmitted (e.g., target or intended) packet from noise introduced by stray electromagnetic waves. 
     However, operating amplifier circuitry to amplify an analog electrical signal generally consumes electrical power. In fact, the amount of electrical power consumed generally increases as the gain (e.g., amount of amplification) applied to analog electrical signals increases. In other words, at least in some instances, increasing the gain applied in a radio frequency system may increase power consumption and, thus, affect (e.g., reduce) operational efficiency of the radio frequency system. 
     To facilitate improving operational efficiency and/or communication reliability, in some instances, a radio frequency system may include multiple antennas coupled to its transceiver circuitry. For example, a (e.g., beamformer) radio frequency system may include an array of multiple antennas to enable the radio frequency system to wirelessly transmit one or more data streams using beamforming (e.g., beamsteering) techniques. Additionally or alternatively, a (e.g., beamformee) radio frequency system may include an array of multiple antennas to enable the radio frequency system to receive multiple concurrently transmitted data streams. 
     However, the number of data streams that can be concurrently received by a beamformee radio frequency system and, thus, that can be concurrently transmitted from a beamformer radio frequency system is generally be limited by the number of antennas utilized by the target beamformee radio frequency system. For example, when the beamformee utilizes a single antenna, the beamformer radio frequency system may wirelessly transmit a single data stream using beamforming techniques. As a further example, when the beamformee utilizes three antennas, the beamformer radio frequency system may concurrently transmit up to three data streams. 
     To implement beamforming techniques, a beamformer radio frequency system may concurrently transmit electromagnetic wave signals from multiple antennas such that additive and/or destructive interference therebetween produces one or more electromagnetic wave beams (e.g., concentrated strength) oriented in a target direction, such as toward a target beamformee radio frequency system. In other words, concurrent transmission of electromagnetic wave signals from multiple antennas of the beamformer radio frequency system may effectively combine the analog electrical signals supplied to the antennas. As such, an analog electrical signal output from an antenna of a beamformee radio frequency system may be a (e.g., linear) combination of stray electromagnetic waves and the analog electrical signals supplied to the antennas of the beamformer radio frequency system reduced by propagation loss resulting therebetween. 
     In other words, orientation of an electromagnetic wave beam produced by a beamformer radio frequency system may be adjusted by adaptively controlling phase and/or magnitude of the analog electrical signals supplied to its antennas. As such, to facilitate implementing beamforming techniques, a radio frequency system may include coding circuitry that operates to process (e.g., encode) a packet before transmission and/or to process (e.g., decode) a packet received from another radio frequency system. For example, to facilitate wirelessly transmitting a data stream using beamforming techniques, coding circuitry in a beamformer radio frequency system may encode the data stream based at least in part on encoding parameters to produce multiple versions of an analog electrical signal corresponding with the data stream. In particular, based at least in part on the encoding parameters, the coding circuitry may process and/or route the data stream such that different versions, which have potentially differing magnitude and/or differing phase, are supplied to different antennas of the beamformer radio frequency system. 
     On the other side, to facilitate receiving a data stream wirelessly transmitted using beamforming techniques, coding circuitry in a beamformee radio frequency system may decode analog electrical signals output from one or more antennas and/or corresponding digital electrical signals based at least in part on decoding parameters. In particular, in some instances, the coding circuitry in the beamformee radio frequency system may reverse the encoding performed by the beamformer radio frequency system and the effects (e.g., combination and/or stray electromagnetic interference) of wireless transmission. In other words, based at least in part on the decoding parameters, the coding circuitry may adjust phase and/or magnitude of an analog electrical signal output from each antenna of the beamformee radio frequency system and/or corresponding digital electrical to facilitate identifying (e.g., separating out) one or more data streams, for example, from one another and/or from noise produced by stray electromagnetic waves. 
     As such, at least in some instances, coding (e.g., encoding and/or decoding) parameters to be applied by radio frequency systems to enable the radio frequency system to wirelessly communicate using beamforming techniques may be dependent at least in part on current communication conditions. For example, a set of communication conditions may include operational parameters of the radio frequency systems, such as the number of antennas utilized by a beamformer radio frequency system, the number of antennas utilized by a beamformee radio frequency system, location of the beamformee radio frequency system relative to the beamformer radio frequency system, the number of data streams to be concurrently transmitted, and/or one or more communication frequencies to be used to wirelessly transmit each data stream. In some instances, the set of communication conditions may additionally include parameters of a wireless communication channel used by the beamformer radio frequency system and the beamformee radio frequency system, such characteristics (e.g., location, type, reflection coefficient, and/or size) of obstructions and/or other environmental conditions present in the wireless communication channel. 
     However, communication conditions often vary, for example, due to a radio frequency system being moved and/or the radio frequency system communicating with different radio frequency systems at different times. To facilitate accounting for potential variations, in some instances, a target beamformee radio frequency system may determine current communication conditions, for example, based at least in part on distortion introduced on a beamforming initiation packet, such as a non-data packet (NDP), received from a beamformer radio frequency system. Additionally, based at least in part on the current communication conditions, the target beamformee radio frequency system may determine coding (e.g., encoding and/or decoding) parameters and return encoding (e.g., beamforming) parameters to the beamformer radio frequency system. 
     As described above, the beamformer radio frequency system may then process a data packet based at least in part on the encoding parameters to facilitate wirelessly transmitting the data packet via one or more electromagnetic wave beams. Additionally or alternatively, the beamformee radio frequency system may process analog electrical signals output from its antennas and/or corresponding digital electrical signals based at least in part on decoding parameters to facilitate identifying the data packet. In other words, at least in some instances, coding (e.g., encoding and/or decoding) parameters determined for different sets of communication conditions may affect operational efficiency and/or communication reliability of radio frequency systems, for example, due to encoding parameters resulting in an electromagnetic wave beam oriented in an improper direction and/or a beamformer radio frequency system re-transmitting dropped packets. 
     Accordingly, to facilitate improving operational efficiency and/or communication reliability of radio frequency systems, the present disclosure provides techniques for implementing and/or operating a testing system to facilitate calibrating and/or testing a radio frequency system under various sets of communication conditions, for example, before commercial deployment of the radio frequency system and/or an electronic device including the radio frequency system. In some instances, a radio frequency system may be calibrated and/or tested by physically reproducing communication conditions and operating the radio frequency within the physically reproduced communication conditions. However, physically reproducing communication conditions is often a complex and/or time consuming process, which, at least in some instances, may limit calibration efficiency and/or testing efficiency of radio frequency systems, for example, due to a wireless communication channel being physically reproduced using heavy equipment and/or an anechoic room. 
     To facilitate improving calibration and/or testing efficiency, in some embodiments, a testing system may include a tester radio frequency system implemented and/or operated to emulate wireless communication, for example, on-chip. In some embodiments, a tester radio frequency system may emulate wireless communication by emulating the effect that transmission of a packet via a wireless communication channel is expected to have on the packet. In other words, before transmitting a packet, the tester radio frequency system may modify magnitude and/or phase of one or more electrical signals corresponding with the packet based at least in part on distortion expected to be introduced due to wireless transmission of the packet, for example, via its coding circuitry. 
     In fact, in some embodiments, emulating wireless communication in this manner may enable calibration and/or testing of another (e.g., device under testing (DUT)) radio frequency system via one or more wired connections. For example, a testee radio frequency system may be wired to the tester radio frequency system in the testing system. In some embodiments, the tester radio frequency system and the testee radio frequency system may be wired in a manner that bypasses their antennas, for example, such that transceiver circuitry of the tester radio frequency system is wired directly to transceiver circuitry of the testee radio frequency system. In other words, an analog electrical signal received by the testee radio frequency system may emulate transmission of one or more corresponding packets from the tester radio frequency system to the testee radio frequency system via a wireless communication channel. 
     As such, during a testing (e.g., calibration) process, a tester radio frequency system may operate similarly to a beamformer radio frequency system and a testee radio frequency system may operate similarly to a beamformee radio frequency. For example, as described above, a beamformer radio frequency system may broadcast a beamforming initiation packet from each of its antennas. However, during the testing process, the tester radio frequency system may additionally process the beamforming initiation packet based on encoding parameters, which emulate the effect of communication conditions currently being tested, and output analog electrical signals indicative of the encoded packet to the testee radio frequency system via one or more wired connections. 
     In some embodiments, an original version of the beamforming initiation packet may be pre-determined and stored in a beamformee radio frequency system and/or a testee radio frequency system. In other words, based on analog electrical signals supplied to its transceiver circuitry, a receiving (e.g., beamformee or testee) radio frequency system may determine a received version of the beamforming initiation packet and compare the received version with the original version to determine distortion introduced by transmission of the beamforming initiation packet. Moreover, when utilizing multiple antennas, the receiving radio frequency system may determine multiple versions of the beamforming initiation packet and compare different versions to determine relative differences in introduced distortion. Based at least in part on the introduced distortion, the receiving radio frequency system may determine communication conditions under which the beamforming initiation packet was transmitted and determine coding (e.g., encoding and/or decoding) parameters accordingly, for example, by selecting a set of coding parameters associated with communication conditions by its current configuration. 
     As described above, in some embodiments, a set of communication conditions may include operational parameters of a beamformer radio frequency system, operational parameters of a beamformee radio frequency system, and/or parameters of a wireless communication channel used by the beamformer radio frequency system and the beamformee radio frequency system. To facilitate improving operational efficiency, in some embodiments, a receiving (e.g., beamformee or testee) radio frequency system may indirectly determine a set of communication conditions by determining phase and/or magnitude relationships between each antenna of a transmitting (e.g., beamformer or tester) radio frequency system and each antenna of the receiving radio frequency system. For example, when the transmitting radio frequency system utilizes eight antennas and the receiving radio frequency system utilizes three antennas, the receiving radio frequency system may determine a current set of communication conditions as an 8×3 communication condition matrix. 
     Additionally, as described above, a beamformee radio frequency may determine coding (e.g., encoding and/or decoding) parameters to be applied to subsequent data packets to account (e.g., compensate) for current communication conditions. For example, when a transmitting (e.g., beamformer or tester) radio frequency system utilizes eight antennas and a receiving (e.g., beamformee or testee) utilizes three antennas, the receiving radio frequency system may determine the set of encoding parameters to be used by the transmitting radio frequency system as 3×8 encoding matrix. Additionally, the receiving radio frequency system may determine the set of decoding parameters to be used by the receiving radio frequency system as 3×3 decoding matrix, for example, which is the inverse of a matrix resulting from combination (e.g., matrix multiplication) of the 3×8 encoding matrix and an 8×3 communication condition matrix. 
     Furthermore, as described above, a beamformee radio frequency system may return encoding (e.g., beamforming) parameters associated with current communication conditions to a beamformer radio frequency system. In this manner, as described above, the beamformer radio frequency system may process subsequent data packets based on the encoding parameters received from the beamformee radio frequency system to facilitate wirelessly transmitting the data packets via one or more electromagnetic wave beams. During normal operation, the beamformee radio frequency system may wirelessly transmit the encoding parameters to the beamformer radio frequency system. 
     On the other hand, during the testing process, in some embodiments, a testee radio frequency system may return the encoding parameters to a tester radio frequency system via one or more wired connections. Based at least in part on the returned encoding parameters, the tester radio frequency system may process a subsequent data packet and output analog electrical signals indicative of the encoded packet to the testee radio frequency system via one or more wired connections. However, as described above, the tester radio frequency system may also utilize encoding parameters, which emulate the effect of communication conditions currently being tested. 
     In other words, during the testing process, the encoding parameters applied by the tester radio frequency system may include channel emulation parameters and/or beamforming parameters. In particular, the tester radio frequency system may process a beamforming initiation packet based on the channel emulation parameters, for example, along with default (e.g., uniform gain and/or uniform phase shift) beamforming parameters. On the other hand, the tester radio frequency system may process subsequent data packets based on the channel emulation parameters as well as updated (e.g., non-default) beamforming parameters returned from the tested radio frequency system. 
     In some embodiments, an original version of a data packet to be transmitted during the testing process may be pre-determined and stored in the testing system. Accordingly, based on analog electrical signals supplied to transceiver circuitry of the testee radio frequency system, the testing system may determine a received version of the data packet and compare the received version with the original version to facilitate evaluating performance of the testee radio frequency system as a beamformee. For example, the testing system may compare the received version with the original version to determine a packet error rate resulting from use of the set of beamforming parameters previously returned to the tester radio frequency system. 
     To facilitate improving performance as a beamformee, in some embodiments, the testing system may adaptively adjust configuration (e.g., programming and/or implementation) of a testee radio frequency system during the testing (e.g., calibration) process. For example, the testing system may adjust a current configuration of the testee radio frequency system such that the testee radio frequency system determines a different set of beamforming parameters if communication conditions are subsequently detected again. Additionally, in some embodiments, the testing system may adjust the current configuration of the testee radio frequency system when use of the previously returned set of beamforming parameters result in a packet error rate greater than an error threshold. In fact, in some embodiments, operation (e.g., performance) of the testee radio frequency system under different sets of communication conditions may be tested and/or calibrated merely be adjusting the channel emulation parameters applied by the tester radio frequency system. In this manner, as will be described in more detail below, the techniques described in the present disclosure may facilitate improving calibration efficiency and/or testing efficiency of a radio frequency system and, thus, an electronic device in which the radio frequency system is deployed, for example, by obviating wireless communication and, thus, physical reproduction of communication conditions during testing and/or calibration of the radio frequency system. 
     To help illustrate, an example of an electronic device  10 , which includes a radio frequency system  12 , is shown in  FIG. 1 . As will be described in more detail below, the electronic device  10  may be any suitable electronic device, such as a computer, a mobile (e.g., portable) phone, a portable media device, a tablet device, a television, a handheld game platform, a personal data organizer, a virtual-reality headset, a mixed-reality headset, a vehicle dashboard, and/or the like. Thus, it should be noted that  FIG. 1  is merely one example of a particular implementation and is intended to illustrate the types of components that may be present in an electronic device  10 . 
     As depicted, in addition to the radio frequency system  12 , the electronic device  10  includes one or more input devices  14 , one or more input/output ports  16 , a processor core complex  18 , one or more storage devices  20 , a power source  22 , memory  24 , and an electronic display  26 . The various components described in  FIG. 1  may include hardware elements (e.g., circuitry), software elements (e.g., a tangible, non-transitory computer-readable medium storing instructions), or a combination of both hardware and software elements. It should be noted that the various depicted components may be combined into fewer components or separated into additional components. For example, the memory  24  and a storage device  20  may be included in a single memory or storage component. 
     As depicted, the processor core complex  18  is operably coupled with memory  24  and the storage device  20 . In this manner, the processor core complex  18  may execute instruction stored in memory  24  and/or the storage device  20  to perform operations, such as instructing the radio frequency system  12  to communicate with another electronic device and/or a communication network. As such, the processor core complex  18  may include one or more general purpose microprocessors, one or more application specific processors (ASICs), one or more field programmable logic arrays (FPGAs), or any combination thereof. 
     In addition to instructions, the memory  24  and/or the storage device  20  may store data to be processed by the processor core complex  18 . Thus, in some embodiments, the local memory and/or the storage device  20  may include one or more tangible, non-transitory, computer-readable mediums. For example, the memory  24  may include random access memory (RAM) and the storage device  20  may include read only memory (ROM), rewritable non-volatile memory, such as flash memory, a hard drive, an optical disc, and/or the like. 
     As depicted, the processor core complex  18  is also operably coupled with the I/O ports  16 . In some embodiments, the I/O ports  16  may enable the electronic device  10  to interface with other electronic devices. For example, a portable storage device may be connected to an I/O port  16 , thereby enabling the processor core complex  18  to communicate with the portable storage device. 
     Additionally, as depicted, the processor core complex  18  is operably coupled to the power source  22 . In this manner, the power source  22  may provide electrical power to the processor core complex  18 , for example, as well as one or more components in the electronic device  10 , such as the radio frequency system  12 . Thus, the power source  22  may include any suitable energy source, such as a rechargeable lithium polymer (Li-poly) battery and/or an alternating current (AC) power converter. 
     Furthermore, as depicted, the processor core complex  18  is operably coupled with the input devices  14 . In some embodiments, an input device  14  may facilitate user interaction with the electronic device  10 , for example, by receiving user inputs and communicating the user inputs to the processor core complex  18 . Thus, in some embodiments, the input devices  14  may include a button, a keyboard, a mouse, a trackpad, and/or the like. Additionally, in some embodiments, the input devices  14  may include touch sensing components implemented in the electronic display  26 . In such embodiments, the touch sensing components may receive user inputs by detecting occurrence and/or position of an object contacting the surface of the electronic display  26 . 
     In addition to enabling user inputs, the electronic display  26  may display images, such as a graphical user interface (GUI) for an operating system, an application interface, a still image, or video content. As depicted, the electronic display  26  is operably coupled to the processor core complex  18 . As such, in some embodiments, the electronic display  26  may display images based at least in part on image data received from the processor core complex  18 . 
     As depicted, the processor core complex  18  is also operably coupled with the radio frequency system  12 . As described above, the radio frequency system  12  may facilitate wirelessly communication with another electronic device and/or a communication network. For example, the radio frequency system  12  may enable the electronic device  10  to communicate with a personal area network (PAN), such as a Bluetooth network, a local area network (LAN), such as an 802.11x Wi-Fi network, and/or a wide area network (WAN), such as an LTE or a millimeter wave (mmWave) cellular network. In other words, the radio frequency system  12  may enable wirelessly communicating data using various communication protocols. 
     Even when using different communication protocols and/or different communication frequencies, operational principles of radio frequency systems  12  may generally be similar. For example, the radio frequency system  12  may convert a digital electrical signal, which digitally represents a (e.g., data) packet to be transmitted, into an analog electrical signal, thereby generating an analog representation of the packet. Additionally, the radio frequency system  12  may amplify the analog electrical signal to a target output power, thereby generating an amplified analog electrical signal, for example, after converting the analog electrical signal from a processing (e.g., intermediate or baseband) frequency to a target communication (e.g., transmission and/or reception) frequency. Based at least in part on the amplified analog electrical signal, the radio frequency system  12  may modulate electromagnetic waves at a radio frequency, thereby wirelessly transmitting the packet via an electromagnetic wave signal. 
     Additionally or alternatively, the radio frequency system  12  may generate an analog electrical signal modulated based at part on power of received (e.g., incident) electromagnetic waves, thereby indicating wirelessly received data via an analog electrical signal. Since received electromagnetic waves often include electromagnetic interference, the radio frequency system  12  may filter and/or amplify the analog electrical radio frequency signals. Furthermore, to facilitate subsequent processing, the radio frequency system  12  may convert the analog electrical signal from the communication (e.g., transmission and/or reception) frequency to a processing (e.g., intermediate or baseband) frequency and/or to a digital electrical signal. Due to similarities in operational principles, the techniques described herein may be applicable to any suitable radio frequency system  12  regardless of communication protocol or communication frequency. 
     As described above, the electronic device  10  may be any suitable electronic device. To help illustrate, one example of a suitable electronic device  10 , specifically a handheld electronic device  10 A, is shown in  FIG. 2 . In some embodiments, the handheld electronic device  10 A may be a portable phone, a media player, a personal data organizer, a handheld game platform, and/or the like. For example, the handheld electronic device  10 A may be a smart phone, such as any iPhone® model available from Apple Inc. 
     As depicted, the handheld electronic device  10 A includes an enclosure  28  (e.g., housing). In some embodiments, the enclosure  28  may protect interior components from physical damage and/or shield them from electromagnetic interference. Thus, a radio frequency system  12  may also be enclosed within the enclosure  28  and internal to the handheld electronic device  10 A. 
     Additionally, as depicted, the enclosure  28  may surround the electronic display  26 . In the depicted embodiment, the electronic display  26  is displaying a graphical user interface (GUI)  29  having an array of icons. By way of example, when an icon is selected be a user input received via an input device  14  or a touch sensing component of the electronic display  26 , an application program may launch. 
     Furthermore, as depicted, input devices  14  open through the enclosure  28 . As described above, the input devices  14  may enable a user to interact with the handheld electronic device  10 A. For example, the input devices  14  may enable the user to activate or deactivate the handheld electronic device  10 A, navigate a user interface to a home screen, navigate a user interface to a user-configurable application screen, activate a voice-recognition feature, provide volume control, and/or toggle between vibrate and ring modes. As depicted, the I/O ports  16  also open through the enclosure  28 . In some embodiments, the I/O ports  16  may include, for example, an audio jack to connect to external devices. 
     To help further illustrate, another example of a suitable electronic device  10 , specifically a tablet electronic device  10 B is shown in  FIG. 3 . As an illustrative example, the tablet electronic device  10 B may be any iPad® model available from Apple Inc. A further example of a suitable electronic device  10 , specifically a computer  10 C, is shown in  FIG. 4 . As an illustrative example, the computer  10 C may be any MacBook® or iMac® model available from Apple Inc. Another example of a suitable electronic device  10 , specifically a watch  10 D, is shown in  FIG. 5 . As an illustrative example, the watch  10 D may be any Apple Watch® model available from Apple Inc. 
     As depicted, the tablet electronic device  10 B, the computer  10 C, and the watch  10 D each also include an electronic display  26 , input devices  14 , I/O ports  16 , and an enclosure  28 . Thus, in some embodiments, the enclosure  28  may enclose a radio frequency system  12  in the tablet electronic device  10 B, the computer  10 C, and/or the watch  10 D. In any case, as described above, a radio frequency system  12  may facilitate wirelessly communication with other electronic devices  10  and/or a communication network. 
     To help illustrate, an example of a radio frequency system  12 , which may be implemented (e.g., deployed) in an electronic device  10 , is shown in  FIG. 6 . As depicted, the radio frequency system  12  includes transceiver circuitry  32 , antennas  34 , and a controller  36 . It should be appreciated that the depicted example is merely intended to be illustrative and not limiting. For example, in other embodiments, a radio frequency system  12  may include a single antenna  34  or more than two antennas  34 . 
     To enable an electronic device  10  to wirelessly communicate via the radio frequency system  12 , in some embodiments, its processor core complex  18  and/or other digital processing circuitry may be communicatively coupled to the transceiver circuitry  32  of the radio frequency system  12 . Generally, digital processing circuitry may process data and/or other types of packets in a digital domain. In other words, digital processing circuitry may process data and/or other types of packets indicated via digital electrical signals, for example, which indicate “0” bits when voltage is below a voltage threshold and “1” bits when voltage is above the voltage threshold. 
     On the other end, as depicted, the transceiver circuitry  32  is coupled to multiple antennas  34 —including at least a first antenna  34 A and an Nth antenna  34 N. However, an antenna  34  generally operates in an analog domain. For example, an antenna  34  may facilitate wireless transmission by modulating electromagnetic (e.g., radio) waves based at least in part on an analog electrical signal received from the transceiver circuitry  32 . Additionally or alternatively, an antenna  34  may facilitate reception of wireless transmissions by outputting an analog electrical signal based at least in part on received (e.g., incident) electromagnetic waves. In other words, the transceiver circuitry  32  may act as an interface between the digital domain (e.g., used by digital processing circuitry) and the analog domain (e.g., used by an antenna  34  and/or analog processing circuitry). 
     To facilitate interfacing the digital domain and the analog domain, as in the depicted example, the transceiver circuitry  32  may include an analog-to-digital converter (ADC)  42  and/or a digital-to-analog converter (DAC)  44 . Generally, the analog-to-digital converter (ADC)  42  may operate to convert an analog electrical signal (e.g., output from an antenna  34 ) into a digital electrical signal (e.g., to be output to the digital processing circuitry  30 ). On the other hand, the digital-to-analog converter (DAC)  44  may generally operate to convert a digital electrical signal (e.g., output from digital processing circuitry) into an analog electrical signal (e.g., to be output to an antenna  34 ). 
     In addition to converting between the digital domain and the analog domain, the transceiver circuitry  32  may include processing circuitry that operates to process electrical signals corresponding with packets to be transmitted from the radio frequency system  12  and/or packets received by the radio frequency system  12 . In some embodiments, the transceiver circuitry  32  may process the electrical signals at least in part in the digital domain and, thus, may include digital processing circuitry, for example, including a modem, a baseband processor, and/or the like. Additionally or alternatively, the transceiver circuitry  32  may process the electrical signals at least in part in the analog domain and, thus, may include analog processing (e.g., front-end) circuitry. 
     Merely as an illustrative example, processing circuitry implemented in the transceiver circuitry  32  may include frequency converter circuitry  46 , amplifier circuitry  48 , phase shift circuitry  50 , and/or filter circuitry  52 . Generally, the filter circuitry  52  may operate to remove noise from an electrical signal, for example, by attenuating frequencies outside a target communication frequency or band. Thus, in some embodiments, the filter circuitry  52  may include one or more bandpass filters. Additionally, in some embodiments, operation of the filter circuitry  52  may be controlled based at least in part on filter parameters, such as one or more target communication frequencies and/or one or more target filter strengths. 
     Furthermore, the amplifier circuitry  48  may generally operate to amplify magnitude (e.g., amplitude) of electrical signals, for example, to facilitate compensating for propagation loss. In some embodiments, the amplifier circuitry  48  may include one or more transmit (e.g., power) amplifiers, which operate to amplify electrical signals to be supplied to the antennas  34 . Additionally or alternatively, the amplifier circuitry  48  may include one or more receipt (e.g., low noise) amplifier, which operate to amplify electrical signals output from the antennas  34 . Furthermore, in some embodiments, operation of the amplifier circuitry  48  may be controlled based at least in part on amplifier parameters, such as a one or more target gain values (e.g., amount of amplification). 
     Additionally, the frequency converter circuitry  46  may generally operate to convert electrical signals between different frequencies. For example, the frequency converter circuitry  46  may convert between a processing (e.g., baseband) frequency used by digital processing circuitry and a communication (e.g., carrier) frequency used by an antenna  34 . Additionally or alternatively, first frequency converter circuitry  46  may convert between the processing frequency and an intermediate frequency, which is between the processing frequency and the communication frequency, while second frequency converter circuitry  46  converts between the intermediate frequency and the communication frequency. Furthermore, in some embodiments, operation of the frequency converter circuitry  46  may be controlled based at least in part on frequency converter parameters, such as one or more target output frequencies. 
     Moreover, the phase shift circuitry  50  may generally operate to phase shift electrical signals, for example, to facilitate implementing beamforming techniques. Thus, in some embodiments, the phase shift circuitry  50  may include delay circuitry, for example, which operates to delay a first version of an electrical signal to be supplied to the first antenna  34 A relative to a second version of the electrical signal to be supplied to the Nth antenna  34 N. Additionally, in some embodiments, operation of the phase shift circuitry  50  may be controlled based at least in part on phase shift parameters, such as one or more target phase shifts. 
     In other words, in some embodiments, operation of processing circuitry implemented in the transceiver circuitry  32  may be controlled based at least in part on processing parameters, for example, including one or more filter parameters, one or more amplifier parameters, one or more frequency converter parameters, and/or one or more phase shift parameters. In fact, in some embodiments, operation of the processing circuitry may be adaptively adjusted based at least in part on current communication conditions, for example, to facilitate balancing operational efficiency (e.g., power consumption) and communication reliability (e.g., transmission distance) and/or to facilitate implementing beamforming techniques. 
     To facilitate adaptively adjusting operation of its processing circuitry, as in the depicted example, the transceiver circuitry  32  may include routing circuitry  54 . Generally, routing circuitry  54  may operate to route electrical signals to appropriate destinations in the radio frequency system  12 , for example, between different portions of the processing circuitry and/or between the processing circuitry and the antennas  34 . As in the depicted example, the routing circuitry  54  may include one or more switching devices  66 . In some embodiments, one or more of the switching devices  66  may be implemented in a multiplexer or a de-multiplexer. Additionally, in some embodiments, the switching devices  66  may include a time division duplex (TDD) switch, for example, which selectively switches between a transmission (e.g., uplink) state and a reception (e.g., downlink) state. Furthermore, in some embodiments, one or more of the switching devices  66  may be a semiconductor switching device, such as a metal-oxide-semiconductor field-effect transistor (MOSFET). 
     Additionally, as in the depicted example, the routing circuitry  54  may include one or more splitters  70  and/or one or more combiners  72 . Generally, a splitter  70  may operate to supply the same electrical signal to multiple different destinations. On the other hand, a combiner  72  may generally operate to combine electrical signals received from multiple different sources into a single electrical signal, for example, which includes multiple different frequency components and/or multiple data streams. 
     In fact, in some embodiments, including splitters  70  and/or combiners  72  in the routing circuitry  54  may facilitate implementing beamforming techniques. As an illustrative example, in a transmitting (e.g., beamformer) radio frequency system  12 , a splitter  70  may operate to output the same version of an electrical signal corresponding with a data stream to multiple different destinations, for example, different portions of the amplifier circuitry  48  operated to apply different gain values and/or different portions of the phase shift circuitry  50  operated to apply different phase shifts. Additionally, to concurrently transmit multiple data streams, a combiner  72  in the transmitting radio frequency system  12  may combine electrical signals corresponding with multiple different data streams into a single electrical signal, which is output to a single destination, such as antenna  34  or subsequent processing circuitry. 
     On the other hand, when a receiving (e.g., beamformee) radio frequency system  12  utilizes multiple antennas  34 , a combiner  72  in the receiving radio frequency system  12  may combine electrical signals corresponding with analog electrical signals output from each of the antennas  34 , for example, after processing by the frequency converter circuitry  46 , the amplifier circuitry  48 , the phase shift circuitry  50 , and/or the filter circuitry  52 . Additionally, to receive multiple concurrently transmitted data streams, a splitter  70  in the receiving radio frequency system  12  may operate to output the same version of an electrical signal corresponding with an analog electrical signal output from an antenna  34  to multiple different destinations, for example, different portions of filter circuitry  52  operated to target different communication frequencies. As such, in some embodiments, operation of the routing circuitry  54  may be controlled based at least in part on routing parameters, such as one or more target switching device states and/or one or more target routing paths (e.g., target source and/or target destination). 
     In some embodiments, the controller  36  may generally control operation of the radio frequency system  12 . Although depicted as a single controller  36 , in other embodiments, one or more separate controllers  36  may be used to control operation of a radio frequency system  12 . To facilitate controlling operation, the controller  36  may include at least one controller processor  38  and/or controller memory  40 . In some embodiments, the controller processor  38  may execute instructions and/or process data stored in the controller memory  40  to determine one or more control commands that instruct processing circuitry and/or routing circuitry  54  in the radio frequency system  12  to perform a control action. Additionally or alternatively, the controller processor  38  may be hardwired with instructions that determine control commands when executed. Furthermore, in some embodiments, the controller processor  38  may be included in the processor core complex  18  and/or separate processing circuitry. 
     Additionally, in some embodiments, the controller memory  40  may be included in memory  24 , a storage device  20 , and/or another tangible, non-transitory computer-readable medium. Furthermore, as in the depicted example, the controller memory  40  may store coding parameters  74 , for example, including channel emulation parameters  76  and/or beamforming parameters  78 . In some embodiments, the coding parameters  74  (e.g., channel emulation parameters  76  and/or beamforming parameters  78 ) may include processing parameters and/or routing parameters to be implemented by the transceiver circuitry  32 . 
     Furthermore, in some embodiments, different sets of coding parameters  74  may be determined for different sets of communication conditions. For example, before transmission of a data packet, the radio frequency system  12  may operate on the packet based at least in part on coding (e.g., encoding) parameters  74  associated with a current set of communication conditions. Additionally or alternatively, the radio frequency system  12  may operate on a received data packet based at least in part on coding (e.g., decoding) parameters  74  associated with a current set of communication conditions. In this manner, as will be described in more detail below, a radio frequency system  12  may be implemented in an electronic device  10  to wirelessly communicate using a wireless communication channel, for example, using beamforming techniques. 
     To help illustrate, an example of a wireless communication system  80 , which includes a first electronic device  10 E and a second electronic device  10 F communicatively coupled via a wireless communication channel  82 , is shown in  FIG. 7 . It should be appreciated that the depicted example is merely intended to be illustrative and not limiting. For example, in other embodiments, the wireless communication system  80  may additionally include another electronic device  10  communicatively coupled to the first electronic device  10 E and/or the second electronic device  10 F via the wireless communication channel  82 . 
     To enable wireless communication, as depicted, the first electronic device  10 E includes a first radio frequency system  12 A and the second electronic device  10 F includes a second radio frequency system  12 B. Additionally, as described above, a radio frequency system  12  may include transceiver circuitry  32  and one or more antennas  34 . In particular, as depicted, the first radio frequency system  12 A includes first transceiver circuitry  32 A and multiple antennas  34 —including at least a first antenna  34 A and an Nth antenna  34 N—each coupled to the first transceiver circuitry  32 A. Additionally, as depicted, the second radio frequency system  12 B includes second transceiver circuitry  32 B and multiple antennas  34 —including at least a second antenna  34 B and an Mth antenna  34 M—each coupled to the second transceiver circuitry  32 B. 
     Furthermore, as described above, transceiver circuitry  32  may route and/or process electrical signals based at least in part on coding parameters  74 . Thus, in some embodiments, coding circuitry  84  that operates based at least in part on the coding parameters  74  may be implemented in the transceiver circuitry  32 . In particular, as depicted, the first transceiver circuitry  32 A includes first coding circuitry  84 A and the second transceiver circuitry  32 B includes second coding circuitry  84 B. 
     As described above, in some embodiments, coding parameters  74  may including routing parameters and/or processing parameters, for example, including one or more filter parameters, one or more amplifier parameters, one or more frequency converter parameters, and/or one or more phase shift parameters. Thus, in some embodiments, the first coding circuitry  84 A may include frequency converter circuitry  46 , amplifier circuitry  48 , phase shift circuitry  50 , filter circuitry  52 , and/or routing circuitry  54  implemented in the first transceiver circuitry  32 A. Additionally, in some embodiments, the second coding circuitry  84 B may include frequency converter circuitry  46 , amplifier circuitry  48 , phase shift circuitry  50 , filter circuitry  52 , and/or routing circuitry  54  implemented in the second transceiver circuitry  32 B. 
     Moreover, as described above, in some embodiments, coding parameters  74  may include beamforming parameters  78 . In other words, in some embodiments, coding circuitry  84  may route and/or process a (e.g., data) packet based at least in part on beamforming parameters  78  to facilitate wirelessly transmitting the packet via one or more electromagnetic wave beams. As such, in some embodiments, one of the first radio frequency system  12 A and the second radio frequency system  12 B may act as a beamformer while the other acts as a beamformee. 
     To help illustrate, an example of a process  86  for operating a transmitting (e.g., beamformer or tester) radio frequency system  12  is described in  FIG. 8  and an example of a process  94  for operating a receiving (e.g., beamformee or testee) radio frequency system  12  is described in  FIG. 9 . Generally, the process  86  for operating a transmitting radio frequency system  12  includes transmitting a beamforming initiation packet (process block  88 ) and determining whether beamforming parameters have been received (decision block  90 ). Additionally, after the beamforming parameters have been received, the process  86  includes transmitting a data stream based on the beamforming parameters (process block  92 ). 
     Although described in a particular order, which represents a particular embodiment, it should be noted that the process  86  may be performed in any suitable order. Additionally, embodiments of the process  86  may omit process blocks and/or include additional process blocks. Moreover, in some embodiments, the process  86  may be implemented at least in part by executing instructions stored in a tangible, non-transitory, computer-readable medium, such as controller memory  40 , using processing circuitry, such as the controller processor  38 . 
     Accordingly, in some embodiments, a controller  36  may instruct a transmitting (e.g., beamformer or tester) radio frequency system  12  to transmit a beamforming initiation packet, for example, by switching a time division duplex (TDD) switching device  66  to its transmission state and/or supplying the beamforming initiation packet to transceiver circuitry  32  of the transmitting radio frequency system  12  (process block  88 ). During normal operation, in some embodiments, a beamformer radio frequency system  12  may wirelessly broadcast the beamforming initiation packet from each of its antennas  34 . Thus, in some embodiments, the transmitting radio frequency system  12  may apply a default set of beamforming parameters  78  to the beamforming initiation packet, for example, which includes uniform gains and uniform phase shifts. Additionally, in some embodiments, the beamforming initiation packet may be a non-data (e.g., null-data) packet (NDP), for example, which only includes header metadata. 
     Furthermore, the transmitting radio frequency system  12  may determine whether a set of updated (e.g., non-default) beamforming parameters  78  has been received (decision block  90 ). As will be described in more detail below, in some embodiments, updated beamforming parameters  78  may be returned and/or fed back to the transmitting radio frequency system  12 . In fact, in some embodiments, the set of updated beamforming parameters  78  may be determined based at least in part on distortion resulting from transmission of the beamforming initiation packet. 
     After the updated set of beamforming parameters  78  has been received, the transmitting radio frequency system  12  may transmit one or more data streams based at least in part on the updated set of beamforming parameters  78  (process block  92 ). For example, coding circuitry  84  in the transmitting radio frequency system  12  may vary gain and/or phase shift applied to a data packet based at least in part on the updated set of beamforming parameters  78 . In other words, in some embodiments, the coding circuitry  84  may operate to produce multiple versions of a data stream, which when supplied to the antennas  34  of a beamformer radio frequency system  12  results in additive and/or destructive interference that produces one or more electromagnetic wave beams oriented in a target direction. 
     As described above, in some embodiments, a beamformer radio frequency system  12  may be operated to concurrently transmit multiple data streams. In such embodiments, the analog electrical signals supplied to the antennas  34  of the beamformer radio frequency system  12  may be a (e.g., linear and/or weighted) combination of the multiple data streams, for example, such that analog electrical signals supplied to different antennas  34  include different versions of the data streams. By operating in this manner, a beamformer radio frequency system  12  may wirelessly transmit one or more data streams to a beamformee radio frequency system  12  via one or more electromagnetic wave beams. 
     As described above, a process  94  for operating a receiving (e.g., beamformee or testee) radio frequency system  12  is described in  FIG. 9 . Generally, the process  94  includes receiving a beamforming initiation packet (process block  96 ) and determining current communication conditions based on the beamforming initiation packet (process block  98 ). Additionally, the process  94  includes determining beamforming parameters based on the current communication conditions (process block  100 ) and transmitting the beamforming parameters (process block  102 ). 
     Although described in a particular order, which represents a particular embodiment, it should be noted that the process  94  may be performed in any suitable order. Additionally, embodiments of the process  94  may omit process blocks and/or include additional process blocks. Moreover, in some embodiments, the process  94  may be implemented at least in part by executing instructions stored in a tangible, non-transitory, computer-readable medium, such as controller memory  40 , using processing circuitry, such as the controller processor  38 . 
     Accordingly, in some embodiments, a controller  36  may instruct a receiving (e.g., beamformee or testee) radio frequency system  12  to receive a beamforming initiation packet, for example, by switching a time division duplex (TDD) switching device  66  to its reception state (process block  96 ). In some embodiments, the receiving radio frequency system  12  may determine one or more received versions of the beamforming initiation packet based at least in part on analog electrical signals supplied to its transceiver circuitry  32 . In fact, when utilizing multiple antennas  34 , the receiving radio frequency system  12  may receive multiple versions of the beamforming initiation packet, for example, each corresponding with one of the antennas  34 . 
     Based at least in part on the one or more received versions of the beamforming initiation packet, the receiving radio frequency system  12  may determine a set of current communication conditions (process block  98 ). Generally, a set of communication conditions includes one or more parameters that can potentially result in a transmitted version of a packet differing from a version determined by the receiving radio frequency system  12  and/or first received version of the packet differing from a second received version of the packet. Thus, in some embodiments, a set of communication conditions may include operational parameters of the radio frequency systems  12 , such as the number of antennas utilized by a beamformer radio frequency system  12 , the number of antennas utilized by a beamformee radio frequency system  12 , location (e.g., distance and/or orientation) of the beamformee radio frequency system  12  relative to the beamformer radio frequency system  12 , the number of data streams to be concurrently transmitted, and/or one or more communication frequencies to be used to wirelessly transmit each data stream. In some embodiments, the set of communication conditions may additionally include parameters of a wireless communication channel  82  used by the beamformer radio frequency system  12  and the beamformee radio frequency system  12 , such as characteristics (e.g., location, type, reflection coefficient, and/or size) of obstructions and/or other environmental conditions present in the wireless communication channel  82 . 
     Additionally, in some embodiments, an original version of the beamforming initiation packet may be pre-determined and stored in a tangible, non-transitory, computer-readable medium of the receiving radio frequency system  12 , for example, in controller memory  40 . In such embodiments, the receiving radio frequency system  12  may retrieve the original version of the beamforming initiation packet and compare it with one or more received versions of the beamforming initiation packet. In this manner, the receiving radio frequency system  12  may determine distortion introduced due to transmission of beamforming initiation and identify a set of communication conditions expected to result in the introduced distortion as the current communication conditions. 
     For example, in some embodiments, the receiving radio frequency system  12  may determine the number of antennas  34  being utilized by a transmitting radio frequency system  12  based on the number of times each of its antennas  34  receives the beamforming initiation packet. Additionally, in some embodiments, the number of antennas  34  being utilized by the receiving radio frequency system  12  may be determined based on the number of analog electrical signals supplied to its transceiver circuitry  32 . Furthermore, in some embodiments, the receiving radio frequency system  12  may determine its relative location and/or obstruction characteristics based at least in part on distortion introduced relative to the original version of the beamforming initiation packet and/or differences in distortion introduced in different received versions of the beamforming initiation packet. 
     Based at least in part on the current communication conditions, the receiving radio frequency system  12  may determine coding (e.g., encoding and/or decoding) parameters  74  including beamforming parameters  78  (process block  100 ). To facilitate determining the coding parameters, in some embodiments, a set of communication conditions may be indirectly expressed as a matrix. For example, when a transmitting radio frequency system  12  utilizes N antennas  34  and the receiving radio frequency system  12  utilizes M antennas  34 , a set of communication conditions may be indirectly expressed as an N×M communication condition matrix with each entry indicating a (e.g., phase, frequency, and/or magnitude) relationship between a corresponding antenna  34  of the transmitting radio frequency system  12  and a corresponding antenna  34  of the receiving radio frequency system  12 . 
     As described above, in some embodiments, the coding (e.g., decoding) parameters  74  to be used by the receiving radio frequency system  12  may be determined to generally reverse the beamforming (e.g., encoding) parameters  78  used by a transmitting radio frequency system  12  and the effect of transmission to the receiving radio frequency system  12 . For example, when a transmitting radio frequency system  12  utilizes N antennas  34  and the receiving radio frequency system  12  utilizes M antennas  34 , the receiving radio frequency system  12  may determine the set of beamforming parameters  78  as an M×N beamforming matrix with each entry indicating a phase and/or magnitude adjustment to be applied to each of up to M data streams. Additionally, the receiving radio frequency system  12  may determine the set of coding (e.g., decoding) parameters  74  to be used by the receiving radio frequency system  12  as an M×M decoding matrix, which is the inverse of a matrix resulting from combination of the M×N beamforming matrix and an N×M communication condition matrix. 
     The receiving (e.g., beamformee or testee) radio frequency system  12  may then transmit an updated set of beamforming parameters  78  to a transmitting (e.g., beamformer or tester) radio frequency system  12  (process block  102 ). During normal operation, in some embodiments, a beamformee radio frequency system  12  may wirelessly transmit a set of updated beamforming parameters  78  to a beamformer radio frequency system  12 , for example, using broadcast techniques and/or beamforming techniques. On other hand, during a testing (e.g., calibration) process, in some embodiments, a testee radio frequency system  12  may transmit the updated set of beamforming parameters to a tester radio frequency system  12  using one or more wired connections, for example, to facilitate obviating wireless communication in a testing system. 
     To help illustrate, an example of a testing system  104 , which includes a first electronic device  10 E and a second electronic device  10 F communicatively coupled via wired connections  106 , is shown in  FIG. 7 . In particular, as depicted, the first radio frequency system  12 A includes first transceiver circuitry  32 A and multiple antennas  34 —including at least a first antenna  34 A and an Nth antenna  34 N. Additionally, as depicted, the second radio frequency system  12 B includes second transceiver circuitry  32 B and multiple antennas  34 —including at least a second antenna  34 B and an Mth antenna  34 M. 
     Since both radio frequency systems  12  include multiple antennas  34 , as in the depicted example, the testing system  104  may be operated to concurrently communicate multiple data streams  107 —including at least a first data stream  107 A and an Mth data stream  107 M. However, it should be appreciated that the depicted example is merely intended to be illustrative and not limiting. For example, in other embodiments, the testing system  104  may be operate to communicate a single data stream  107  or more than two (e.g., three or eight) data streams  107 . 
     As described above, to facilitate communicating using beamforming techniques, radio frequency systems  12  may include coding circuitry  84  that operates (e.g., routes and/or processes) on electrical signals based at least in part on coding parameters  74 . Thus, to test beamforming performance, as depicted, the first transceiver circuitry  32 A includes first coding circuitry  84 A and the second transceiver circuitry  32 B includes second coding circuitry  84 B. As such, in some embodiments, one of the first radio frequency system  12 A and the second radio frequency system  12 B may act as a tester radio frequency system  12 , which operates similarly to a beamformer in a wireless communication system  80 , while the other acts as a testee radio frequency system  12 , which operates similarly to a beamformee in the wireless communication system  80 . 
     However, in the testing system  104 , as depicted, the first radio frequency system  12 A and the second radio frequency system  12 B may be coupled via one or more wired connections  106 . For example, a first wired connection  106 A may be coupled between the first radio frequency system  12 A and the second radio frequency system  12 B in a manner that bypasses the antennas  34  of the first radio frequency system  12 A and the second antenna  34 B of the second radio frequency system  12 B. Additionally, an Mth wired connection  106 M may be coupled between the first radio frequency system  12 A and the second radio frequency system  12 B in a manner that bypasses the antennas  34  of the first radio frequency system  12 A and the Mth antenna  34 M of the second radio frequency system  12 B. 
     Moreover, as in the depicted example, a feedback wired connection  106 F may be coupled between the first radio frequency system  12 A and the second radio frequency system  12 B. In some embodiments, the feedback wired connection  106  may be dedicated to communication of beamforming parameters  78 . In other embodiments, the feedback wired connection  106  may obviated and, thus, optional, for example, due to the testing system  104  instead returning beamforming parameters  78  using the first wired connection  106 A and/or the Mth wired connection  106 M. 
     Additionally, in some embodiments, one or more of the wired connections  106  may be included in a cable bundle. For example, the first wired connection  106 A, the Mth wired connection  106 M, the feedback wired connection  106 F, or any combination thereof may be included in a cable bundle connected between the first radio frequency system  12 A and the second radio frequency system  12 B. In other words, in some embodiments, the first transceiver circuitry  32 A of the first radio frequency system  12 A and the second transceiver circuitry  32 B of the second radio frequency system  12 B may be directly wired together, which, at least in some instances, may obviate wireless communication in the testing system  104  and, thus, complete physical reproduction of communication conditions during the testing (e.g., calibration) process. 
     Instead, during the testing process, a tester radio frequency system  12  may emulate the effects of wireless transmission via a wireless communication channel  82 , for example, without actually transmitting packets via the wireless communication channel  82 . To emulate wireless transmission via a wireless communication channel  82 , as described above, the tester radio frequency system  12  may route and/or process a (e.g., data or beamforming initiation) packet based on a set of channel emulation parameters  76 , for example, in addition to a set of beamforming parameters  78 . In other words, although generally operating in a similar manner, operation of a tester radio frequency system  12  may nevertheless differ slightly from normal operation of a beamformer radio frequency system  12  in a wireless communication system  80 . 
     To help illustrate, an example of a process  108  for operating a tester radio frequency system  12  is described in  FIG. 11 . Generally, the process  108  includes determining channel emulation parameters (process block  110 ), modifying a packet based on the channel emulation parameters (process block  112 ), and transmitting a modified version of the packet via a wired connection (process block  114 ). In some embodiments, the packet may be a beamforming initiation packet. Additionally or alternatively, the packet may be a data packet, for example, included in a data stream  107  transmitted after return of updated beamforming parameters  78 . 
     Although described in a particular order, which represents a particular embodiment, it should be noted that the process  108  may be performed in any suitable order. Additionally, embodiments of the process  108  may omit process blocks and/or include additional process blocks. Moreover, in some embodiments, the process  108  may be implemented at least in part by executing instructions stored in a tangible, non-transitory, computer-readable medium, such as controller memory  40 , using processing circuitry, such as the controller processor  38 . 
     Accordingly, in some embodiments, a controller  36  of a tester radio frequency system  12  may determine a set of channel emulation parameters  76  (process block  110 ). As described above, in some embodiments, a set of channel emulation parameters  76  may facilitate emulating the effect of transmission via a wireless communication channel  82  by describing an expected relationship between each antenna  34  of a transmitting (e.g., tester or beamformer) radio frequency system  12  and each antenna  34  of a receiving (e.g., testee or beamformee) radio frequency system  12 . For example, when a transmitting radio frequency system  12  utilizes N antennas  34  and the receiving radio frequency system  12  utilizes M antennas  34 , the set of channel emulation parameters  76  may be expressed as an N×M channel emulation matrix with each entry indicating a (e.g., phase, frequency, and/or magnitude) relationship between a corresponding antenna  34  of the transmitting radio frequency system  12  and a corresponding antenna  34  of the receiving radio frequency system  12 . 
     However, in some embodiments, the number of antennas  34  included in the tester radio frequency system  12  may actually differ from the number of antennas  34  that will be included in a beamformer radio frequency system  12 , for example, since wireless communication may be obviated during the testing (e.g., calibration) process. In fact, in some embodiments, the tester radio frequency system  12  may be implemented without antennas  34 . At least in some instances, utilizing a tester radio frequency system  12  with a different number of antennas  34  compared to a target (e.g., actual) beamformer radio frequency system  12  may facilitate further improving testing and/or calibration efficiency, for example, by enabling beamformee performance of a radio frequency system  12  to be tested and/or calibrated before design of the target beamformer radio frequency system  12  is completed. 
     Additionally, in some embodiments, various sets of channel emulation parameters  76  may be pre-determined and stored in a tangible, non-transitory, computer-readable medium of a testing system  104 , such as controller memory  40 . Thus, in such embodiments, the tester radio frequency system  12  may retrieve a set of channel emulation parameters  76  to be tested from the tangible, non-transitory, computer-readable medium. Additionally or alternatively, the channel emulation parameters  76  may be manually input, for example, via one or more user inputs received via an input device  14 . In fact, in some embodiments, operation under different sets of communication conditions may be tested merely by adjusting the channel emulation parameters  76 . For example, the number of antennas  34  used by the radio frequency systems  12  may be adjusted by adjusting dimensions of a channel emulation matrix. 
     Additionally, the tester radio frequency system  12  may modify a (e.g., data or beamforming initiation) packet based at least in part on coding (e.g., encoding) parameters  74  including the channel emulation parameters  76  (process block  112 ). As described above, in some embodiments, the coding (e.g., encoding) parameters  74  may also include beamforming parameters  78 . As such, in some embodiments, the tester radio frequency system  12  may adjust magnitude and/or phase of an electrical signal based at least in part on the channel emulation parameters  76  and the beamforming parameters  78 . 
     However, as described above, in some embodiments, the tester radio frequency system  12  may process different packets using different sets of beamforming parameters  78 . For example, when a packet is a beamforming initiation packet, the tester radio frequency system  12  may utilize a default set of beamforming parameters  78 , which results in application of uniform gains and uniform phase shifts. On the other hand, when a packet is a data packet transmitted after the beamforming initiation packet, the tester radio frequency system  12  may utilize an updated set of beamforming parameters  78  returned from a testee radio frequency system  12 , for example, which results in application of varied gains and/or varied phase shifts. 
     Moreover, as described above, a set of beamforming parameters  78  to be utilized by the tester radio frequency system  12  may be determined based at least in part on communication conditions. For example, when a transmitting radio frequency system  12  utilizes N antennas  34  and the receiving radio frequency system  12  utilizes M antennas  34 , the beamforming parameters  78  may be expressed as an M×N beamforming matrix with each entry indicating a phase and/or magnitude adjustment to be applied to each of up to M data streams  107 . 
     In some embodiments, the tester radio frequency system  12  may successively apply the beamforming parameters  78  followed by the channel emulation parameters  76 , for example, by applying a set of beamforming parameters  78  followed by a set of channel emulation parameters  76 . In other words, when a transmitting radio frequency system  12  utilizes N antennas  34  and a receiving radio frequency system  12  utilizes M antennas  34 , the tester radio frequency system  12  may apply an M×N beamforming matrix followed by an N×M channel emulation matrix and, thus, effectively applying an M×M encoding matrix. Accordingly, in other embodiments, the tester radio frequency system  12  may process and/or route a packet based at least in part on the M×M encoding matrix, thereby producing up to M modified versions of the packet. 
     The tester radio frequency system  12  may then transmit one or more modified versions of the packet via one or more wired connections  106  (process block  114 ). For example, the tester radio frequency system  12  may transmit a first modified version of the packet to transceiver circuitry  32  of a testee radio frequency system  12  via a first wired connection  106 A and an Mth modified version of the packet to the transceiver circuitry  32  of the testee radio frequency system  12  via an Mth wired connection  106 M. As described above, when the packet transmitted to the testee radio frequency system  12  is a data packet, a testing system  104  may determine performance of the testee radio frequency system  12  as a beamformee and adaptively adjust operation of the testee radio frequency system  12  accordingly. 
     To help illustrate, an example of a process  116  for operating a testing system  104  and/or a testee radio frequency system  12  included in the testing system  104  is described in  FIG. 12 . Generally, the process  116  includes transmitting beamforming parameters via a wired connection (process block  118 ), determining whether a data packet has been received (decision block  120 ), and determining an error rate of the data packet after receipt of the data packet (process block  122 ). Additionally, the process  116  includes determining whether the error rate is greater than an error threshold (decision block  124 ), maintaining a current configuration of a testee radio frequency system when the error rate is not greater than the error threshold (process block  126 ), and modifying the current configuration of the testee radio frequency system when the error rate is greater than the error threshold (process block  128 ). 
     Although described in a particular order, which represents a particular embodiment, it should be noted that the process  116  may be performed in any suitable order. Additionally, embodiments of the process  116  may omit process blocks and/or include additional process blocks. Moreover, in some embodiments, the process  116  may be implemented at least in part by executing instructions stored in a tangible, non-transitory, computer-readable medium, such as controller memory  40 , using processing circuitry, such as the controller processor  38 . 
     Accordingly, in some embodiments, a controller  36  in a testing system  104  may instruct a testee radio frequency system  12  to transmit a set of beamforming parameters  78  to a tester radio frequency system  12  via one or more wired connections  106 , for example, by switching a time division duplex (TDD) switching device  66  in the testee radio frequency system  12  to its transmission state (process block  118 ). As described above, in some embodiments, the testee radio frequency system  12  may transmit the beamforming parameters  78  via a feedback wired connection  106 F. Additionally or alternatively, the testee radio frequency system  12  may transmit the beamforming parameters  78  via another wired connection  106 , such as a first wired connection  106 A or an Mth wired connection  106 M, coupled between transceiver circuitry  32  of the testee radio frequency system  12  and transceiver circuitry of the tester radio frequency system  12 . Furthermore, as described above, the tester radio frequency system  12  may operate on subsequent data packets based at least in part on an updated set of beamforming parameters  78  returned from the testee radio frequency system  12  and transmit one or more modified versions of the data packets to the testee radio frequency system  12  via corresponding wired connections  106 . 
     Once the testee radio frequency system  12  receives a data packet from the tester radio frequency system  12 , the testing system  104  (e.g., testee radio frequency system  12 ) may determine an error rate of the data packet (process block  122 ). In some embodiments, an original version of one or more data packets to be transmitted during the testing process may be pre-determined and stored in a tangible, non-transitory, computer-readable medium of the testing system  104 , such as controller memory  40 . Thus, in such embodiments, the testing system  104  may retrieve the original version of a data packet from the tangible, non-transitory, computer-readable medium and compare one or more received versions of the data packet with the original version to determine a (e.g., absolute) distortion and, thus, an (e.g., absolute) error rate produced in the data packet due to application of the updated set of beamforming parameters  78  by the tester radio frequency system  12 . Additionally or alternatively, the testing system  104  may compare different versions of the data packet received from the tester radio frequency system  12  to determine a (e.g., relative) distortion and, thus, an (e.g., relative) error rate produced in the data packet due to application of the updated set of beamforming parameters  78 . 
     Furthermore, the testing system  104  (e.g., testee radio frequency system  12 ) may determine whether the error rate of the data packet is greater than an error threshold (decision block  124 ). In some embodiments, the error threshold may be pre-determined and stored in a tangible, non-transitory, computer-readable medium of the testing system  104 , such as controller memory  40 . Thus, in such embodiments, the testing system  104  may retrieve the error threshold from the tangible, non-transitory, computer-readable medium and compare the error rate of the data packet against the error threshold. 
     When the error rate is not greater than the error threshold, the testing system  104  may determine that performance of the testee radio frequency system  12  as a beamformee is satisfactory and, thus, a current configuration of the testee radio frequency system  12  (process block  126 ). In other words, when the error rate is not greater than the error threshold, the testing system  104  may maintain the current configuration of the testee radio frequency system  12  such that subsequent determination of the same communication conditions by the testee radio frequency system  12  results in determination of the same set of updated beamforming parameters  78 . On the other hand, when the error rate of the data packet is greater than the error threshold, the testing system  104  may determine that performance of the testee radio frequency system  12  as a beamformee is not satisfactory and, thus, adjust the current configuration of the testee radio frequency system  12  (process block  128 ). In other words, when the error rate is greater than the error threshold, the testing system  104  may adjust the current configuration of the testee radio frequency system  12  such that subsequent determination of the same communication conditions by the testee radio frequency system  12  results in determination of a different set of updated beamforming parameters  78 . 
     In this manner, the techniques described in the present disclosure may facilitate improving testing and/or calibration efficiency of radio frequency systems. As described above, at least in some instances, wireless communication performance of a radio frequency system under various sets of communication conditions may be tested and/or calibrated, for example, before commercial deployment of the radio frequency system and/or an electronic device including the radio frequency system. Since physically reproducing wireless communication conditions is often a complex and/or time consuming process, the present disclosure provides techniques that enable testing and/or calibrating wireless communication performance of a radio frequency system via one or more wired connections, for example, by emulating the effect of wireless transmission via a wireless communication channel. In other words, the techniques described in the present disclosure may enable obviating actual wireless communication and, thus, complete physical reproduction of communication condition, which, at least in some instances, may facilitate improving testing and/or calibration efficiency of radio frequency systems. 
     The specific embodiments described above have been shown by way of example, and it should be understood that these embodiments may be susceptible to various modifications and alternative forms. It should be further understood that the claims are not intended to be limited to the particular forms disclosed, but rather to cover all modifications, equivalents, and alternatives falling within the spirit and scope of this disclosure.

Metadata:
Filing Date: 20190409
Publication Date: 20200609
Grant Date: 20200609
Priority Date: 20190409
Inventors: COHEN, MIK VH
SHIMON, RAN
GERSHONI, SHAY
Assignee: APPLE INC
CPC Classifications: [{"code": "H04B7/0617", "inventive": true, "first": true, "tree": "[]"}, {"code": "H04B17/11", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04B17/21", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04B17/391", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04B17/21", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04B17/12", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04B7/0617", "inventive": true, "first": true, "tree": "[]"}, {"code": "H04B7/0617", "inventive": true, "first": true, "tree": "[]"}, {"code": "H04B17/21", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04B17/11", "inventive": true, "first": false, "tree": "[]"}]
Family ID: 70973201