Time division duplex (TDD) antenna system

Abstract

One example includes an automatic synchronization TDD antenna system. The system includes an antenna system that transmits a transmit signal and receives a receive signal, and an antenna control circuit coupled to a user communication system. The antenna control circuit includes a transmission line measurement circuit that determines a signal loss through a transmission line cable coupled to the antenna system, and an amplitude adjustment circuit that adjusts an amplitude of the transmit signal and / or receive signal based on the signal loss. A transmit detection circuit monitors a signal power of the transmit signal, and a controller switches the amplitude adjustment circuit from a receive mode to a transmit mode in response to the monitored signal power exceeding a predetermined threshold. In the receive mode, the adjustment circuit applies a receive amplitude adjustment to the receive signal, and in the transmit mode, the adjustment circuit applies a transmit amplitude adjustment to the transmit signal.

Description

TECHNICAL FIELD

[0001] The present disclosure relates generally to communication systems, and more particularly to time division duplex (TDD) antenna systems. BACKGROUND

[0002] An antenna array (or array antenna) is a set of multiple antenna elements that work together as a single antenna to transmit or receive radio waves. The individual antenna elements can be connected by circuitry to a receiver and / or transmitter that applies appropriate amplitude and / or phase adjustments to the signals received and / or transmitted by the antenna elements. When used for transmission, the radio waves radiated by each individual antenna element combine and superimpose on each other, adding together constructively in the desired direction to enhance the power radiated in that direction and canceling to reduce the power radiated in other directions. SUMMARY

[0003] One example includes an automatically synchronized TDD antenna system. The system includes an antenna system that transmits a transmit signal and receives a receive signal and an antenna control circuit coupled to a user communication system. The antenna control circuit includes a transmission line measurement circuit that determines a signal loss through a transmission line cable coupled to the antenna system and an amplitude adjustment circuit that adjusts an amplitude of the transmit signal and / or the receive signal based on the signal loss. A transmit detection circuit monitors a signal power of the transmit signal, and a controller switches the amplitude adjustment circuit from a receive mode to a transmit mode in response to the monitored signal power exceeding a predetermined threshold. In the receive mode, the adjustment circuit applies a receive amplitude adjustment to the receive signal, and in the transmit mode, the adjustment circuit applies a transmit amplitude adjustment to the transmit signal.

[0004] Another example includes a method for transmitting at least one of a transmit signal and a receive signal via a time division duplex (TDD) antenna communication system including an antenna system. The method includes providing a calibration signal from an antenna control circuit to the antenna system on at least one transmission line cable and receiving a return signal on the at least one transmission line cable corresponding to the calibration signal retransmitted from the antenna system back to the antenna control circuit. The method also includes determining a signal loss between the antenna system and the antenna control circuit over the at least one transmission line cable based on the return signal and adjusting an amplitude of a receive signal received via the at least one transmission line cable in a receive mode based on the determined signal loss. The method also includes monitoring a signal power of a transmit signal obtained from a user communication system and switching an amplitude adjustment circuit from the receive mode to a transmit mode in response to the monitored signal power exceeding a predetermined threshold. The method also includes adjusting the amplitude of the transmit signal in the transmit mode based on the determined signal loss. BRIEF DESCRIPTION OF DRAWINGS

[0005] Figure 1 An example of a communication system is shown.

[0006] Figure 2 An example of an antenna control circuit is shown.

[0007] Figure 3 An example of a calibration of a communication system is shown.

[0008] Figure 4 Another example of a calibration of a communication system is shown.

[0009] Figure 5 An example of a calibration circuit is shown.

[0010] Figure 6 Another example of a calibration circuit is shown.

[0011] Figure 7 An example of a transmission line measurement circuit is shown.

[0012] Figure 8 An example of a controller is shown.

[0013] Figure 9 An example of a TDD communication flow is shown.

[0014] Figure 10 An example of an amplitude adjustment circuit is shown.

[0015] Figure 11 Another example of an amplitude adjustment circuit is shown.

[0016] Figure 12 Another example of an amplitude adjustment circuit is shown.

[0017] Figure 13 Another example of an amplitude adjustment circuit is shown.

[0018] Figure 14 Another example of an amplitude adjustment circuit is shown.

[0019] Figure 15 Another example of an amplitude adjustment circuit is shown.

[0020] Figure 16 An example of a method for transmitting at least one of a transmit signal and a receive signal via a time division duplex (TDD) antenna system including an antenna is shown. DETAILED DESCRIPTION

[0021] The present disclosure relates generally to communication systems, and more particularly to time division duplex (TDD) antenna systems. A communication system can be implemented that includes a user communication system and an antenna system. As one example, the communication system can be implemented as a wireless broadband communication system (such as using a Long Term Evolution (LTE) communication standard). The antenna system can be physically communicatively coupled (e.g., via a set of transmission line cables) to an antenna control circuit that is coupled to the user communication system to provide enhanced wireless communication capabilities for the communication system, such as to provide wireless extension or capabilities of the user communication system to communicate (e.g., in a time division duplex (TDD) manner) with a base station. For example, the antenna system can provide wireless communication capabilities of the user communication system based on the user communication system being located in a location that prevents or hinders wireless connection with a base station based on, for example, intervening physical barriers or extreme range.

[0022] The antenna system includes one or more antenna arrays and calibration circuitry. The antenna arrays can be arranged as any of a variety of antenna arrays to provide respective one or more wireless signals to be transmitted from and / or received at the antenna system. For example, the antenna arrays can include arrangements of antenna elements (e.g., stripline conductors) to provide signal diversity between two or more respective signal paths, such as based on polarization diversity (e.g., orthogonal polarization of two separate signal paths). The antenna arrays can each thus transmit and receive signals based on defined standards of user communication system operation, such as in a TDD manner.

[0023] As described herein, antenna control circuitry can determine, for example, the cable loss of the interconnect between the antenna system and the user communication system during calibration. Therefore, antenna control circuitry can be implemented to provide attenuation of the transmitted signal (hereinafter “transmitted signal”) provided from the user communication system via the antenna array in a manner that allows the transmitted signal to be transmitted at or below a predetermined Effective Isotropic Radiated Power (EIRP) defined by the operating criteria of the user communication system. Additionally, also as described herein, antenna control circuitry can be configured to monitor the signal power on the corresponding communication path to facilitate TDD operation of the communication system without any input from the user communication system. Therefore, antenna systems can be installed to cooperate with the user communication system in a manner substantially agnostic to the interconnect between the antenna control circuitry and the antenna system, without requiring active communication between the antenna system and the user communication system.

[0024] Figure 1 An example of communication system 10 is shown. Communication system 10 can be implemented as a wireless broadband communication system (such as using the Long Term Evolution (LTE) communication standard). Figure 1 In the example, communication system 10 includes user communication system 12, antenna control circuitry 13, and antenna system 14. As an example, user communication system 12 may correspond to a wireless gateway, such as one that facilitates wireless communication (e.g., Wi-Fi, Bluetooth, and / or cellular communication) between one or more user devices and wireless networks (such as cellular networks or other wide area networks (WANs)).

[0025] exist Figure 1 In the example, antenna system 14 is communicatively coupled to antenna control circuitry 13 via at least one transmission line cable 16 (e.g., RG6 cable), such that antenna control circuitry 13 interconnects user communication system 12 (via another transmission line cable) and antenna system 14. As an example, antenna system 14 can provide enhanced wireless communication capabilities to user communication system 12, such as providing wireless extension or capability for communication with base station (e.g., in time-division duplex (TDD) mode). For example, antenna system 14 can provide wireless communication capabilities to user communication system 12 based on its location, which is based on, for example, an intervening physical barrier or extreme range that prevents or hinders wireless connectivity with base station.

[0026] The antenna system 14 includes one or more antenna arrays 18 and calibration circuitry 20. The antenna arrays 18 can be arranged as any of a variety of antenna arrays to provide a respective one or more wireless signals to be transmitted from and / or received at the antenna system 14. For example, the antenna arrays 18 can include an arrangement of antenna elements (e.g., stripline conductors) to provide signal diversity between two or more respective signal paths, such as based on polarization diversity. For example, the antenna arrays 18 can include two separate arrays of orthogonally polarized antenna elements to provide orthogonally polarized signals that propagate in two separate respective signal paths between the user communication system 12 and the antenna system 14 through the antenna control circuitry 13. The antenna arrays 18 can each thus transmit and receive signals bidirectionally based on defined standards by which the user communication system 12 operates, such as in a TDD manner. In Figure 1 In the example, signals transmitted from and received at the antenna arrays 18 are shown as signal “RF,” and the same signals that propagate bidirectionally along the transmission line cable 16 are shown as signal “TS.”

[0027] The antenna control circuitry 13 includes transmission line measurement circuitry 22 and amplitude adjustment circuitry 24. The transmission line measurement circuitry 22 is configured to determine a signal loss through the at least one transmission line cable 16 between the antenna system 14 and the antenna control circuitry 13. For example, the transmission line measurement circuitry 22 can periodically initiate a calibration operation (e.g., in response to a calibration command) during and / or after installation of the antenna system 14. As one example, during a calibration operation, the transmission line measurement circuitry 22 can be configured to generate a calibration signal, such as a radio frequency (RF) signal, that can be transmitted from the antenna control circuitry 13 to the antenna system 14 via the transmission line cable 16, such that the calibration signal can be retransmitted from the antenna system 14 back to the antenna control circuitry 13 via the transmission line cable 16. The transmission line measurement circuitry 22 can thus measure at least one characteristic (e.g., power) of the return signal to determine a signal loss exhibited by the transmission line cable 16.

[0028] In response to determining the signal loss, the amplitude adjustment circuit 24 can be configured to adjust an amplitude of at least one of the transmit signal emitted from the antenna system 14 and the receive signal received at the antenna system 14 based on the determined signal loss. As described herein, the term "transmit signal" refers to a signal originating from the user communication system 12, propagating through the transmission line cable 16 as signal TS, and emitted from the antenna system 14 as signal RF via the antenna array 18. Similarly, the term "receive signal" refers to a signal received at the antenna system 14 as signal RF via the antenna array 18, propagating through the transmission line cable 16 as signal TS, and provided to the user communication system 12. The amplitude adjustment circuit 24 can thus adjust the amplitude of the transmit signal and the receive signal in the individual respective signal paths in the antenna control circuit 13 based on the signal loss determined during the calibration operation.

[0029] For example, the communication system 10 can be configured to operate based on a predetermined communication standard, which can specify a predetermined maximum effective isotropic radiated power (EIRP), such as +23 dBm for the transmit signal. As one example, the amplitude adjustment circuit 24 can include one or more variable circuit elements (VCEs) that amplify or attenuate the transmit signal (e.g., up to less than the predetermined maximum EIRP) and / or the receive signal (e.g., up to less than a maximum saturation power associated with the antenna control circuit 13 and / or the user communication system 12). For example, the antenna array 18 can be designed to have sufficient gain, or the antenna control circuit 13 can have sufficiently high gain to provide the transmit signal at a power level greater than the predetermined maximum EIRP (e.g., to overcome power loss of the transmission line cable 16 regardless of the length of the transmission line cable 16) such that the transmit signal can be attenuated all the way down to approximately the predetermined maximum EIRP. The antenna system 14 can thus be installed in a substantially length- and / or loss-characteristic-agnostic manner to determine the signal loss of the transmission line cable 16 based on the calibration operation.

[0030] In Figure 1In the example of FIG. 1, the antenna control circuit 13 further includes a transmit detection circuit 28 and a controller 26. As previously described, the communication system 10 can operate based on a TDD communication standard such that transmit signals and receive signals can be interleaved with one another on a given signal path between the user communication system 12 and the antenna array 18. The transmit detection circuit 28 can be configured to measure power on a given signal path in the antenna control circuit 13 to determine whether the user communication system 12 is transmitting a transmit signal. Accordingly, in response to determining whether the user communication system 12 is transmitting a transmit signal, the controller 26 can switch the adjustment circuit 24 from a receive mode (e.g., as a default mode) to a transmit mode to facilitate transmission of the transmit signal from the antenna system 14 via the antenna array 18. Additionally, in response to the transmit detection circuit 28 detecting a reduction in power (e.g., less than a predetermined threshold) of the signal path, the controller 26 can switch the adjustment circuit 24 from the transmit mode back to the receive mode (e.g., upon expiration of a timer).

[0031] In response to the transmit detection circuit 28 determining that the user communication system 12 is transmitting a transmit signal (such as based on the power on the signal path being greater than a predetermined threshold), the controller 26 can provide a signal to the amplitude adjustment circuit 24 to switch the signal path from the receive mode to the transmit mode. Accordingly, the amplitude adjustment circuit 24 can provide appropriate amplitude adjustments to the transmit signal (e.g., via the VCE) to facilitate transmission of the transmit signal from the antenna system 14 via the antenna array 18. As one example, the amplitude adjustment circuit 24 can include a power amplifier and / or a filter in each of the transmit switchable portion and the receive switchable portion of the signal path, and / or can include a shorted bypass path in one of the transmit signal path and the receive signal path.

[0032] Accordingly, the antenna system 14 can operate to facilitate bi-directional TDD communication between transmit signals and receive signals without requiring communication or signal transmission from the user communication system 12. Thus, the antenna system 14 can be installed in a simple manner that is largely independent of the operation of the user communication system 12. Additionally, as previously described, the antenna system 14 can be installed in a manner that is agnostic to the length of the transmission line cable 16 interconnecting the antenna system 14 and the antenna control circuit 13. Accordingly, and as described in greater detail herein, the antenna system 14 can be simply installed to effectively facilitate wireless communication between the user communication system 12 and a network hub (e.g., a base station).

[0033] Figure 2 An example of an antenna control circuit 50 is shown. The antenna control circuit 50 can correspond to Figure 1 the antenna control circuit 13 in the example of FIG. 1. Accordingly, in the following description of the example of FIG. 2, reference will be made to Figure 2 the example of FIG. 1. Figure 1 An example of an antenna control circuit 50 is shown. The antenna control circuit 50 can correspond to Figure 1 the antenna control circuit 13 in the example of FIG. 1. Accordingly, in the following description of the example of FIG. 2, reference will be made to Figure 2 the example of FIG. 1. Figure 1 An example of an antenna control circuit 50 is shown. The antenna control circuit 50 can correspond to Figure 1 the antenna control circuit 13 in the example of FIG. 1. Accordingly, in the following description of the example of FIG. 2, reference will be made to Figure 2 the example of FIG. 1. Figure 1 An example of an antenna control circuit 50 is shown. The antenna control circuit 50 can correspond to Figure 1 the antenna control circuit 13 in the example of FIG. 1. Accordingly, in the following description of the example of FIG. 2, reference will be made to Figure 2 the example of FIG. 1. Figure 1 An example of an antenna control circuit 50 is shown. The antenna control circuit 50 can correspond to Figure 1 the antenna control circuit 13 in the example of FIG. 1. Accordingly, in the following description of the example of FIG. 2, reference will be made to Figure 2 the example of FIG. 1. Figure 1 An example of an antenna control circuit 50 is shown. The antenna control circuit 50 can correspond to Figure 1 the antenna control circuit 13 in the example of FIG. 1. Accordingly, in the following description of the example of FIG. 2, reference will be made to Figure 2 the example of FIG. 1. Figure 1 An example of an antenna control circuit 50 is shown. The antenna control circuit 50 can correspond to Figure 1 the antenna control circuit 13 in the example of FIG. 1. Accordingly, in the following description of the example of FIG. 2, reference will be made to Figure 2 the example of FIG. 1. Figure 1 An example of an antenna control circuit 50 is shown. The antenna control circuit 50 can correspond to Figure 1 the antenna control circuit 13 in the example of FIG. 1. Accordingly, in the following description of the example of FIG. 2, reference will be made to Figure 2 the example of FIG. 1. Figure 1 An example of an antenna control circuit 50 is shown. The antenna control circuit 50 can correspond to Figure 1 the antenna control circuit 13 in the example of FIG. 1. Accordingly, in the following description of the example of FIG. 2, reference will be made to Figure 2 the example of FIG. 1. Figure 1 An example of an antenna control circuit 50 is shown. The antenna control circuit 50 can correspond to Figure 1 the antenna control circuit 13 in the example of FIG. 1. Accordingly, in the following description of the example of FIG. 2, reference will be made to Figure 2 the example of FIG. 1. Figure 1 An example of an antenna control circuit 50 is shown. The antenna control circuit 50 can correspond to Figure 1 the antenna control circuit 13 in the example of FIG. 1. Accordingly, in the following description of the example of FIG. 2, reference will be made to Figure 2 the example of FIG. 1. Figure 1 An example of an antenna control circuit 50 is shown. The antenna control circuit 50 can correspond to Figure 1 the antenna control circuit 13 in the example of FIG. 1. Accordingly, in the following description of the example of FIG. 2, reference will be made to Figure 2 the example of FIG. 1. Figure 1 An example of an antenna control circuit 50 is shown. The antenna control circuit 50 can correspond to Figure 1 the antenna control circuit 13 in the example of FIG. 1. Accordingly, in the following description of the example of FIG. 2, reference will be made to Figure 2 the example of FIG. 1. Figure 1 An example of an antenna control circuit 50 is shown. The antenna control circuit 50 can correspond to Figure 1 the antenna control circuit 13 in the example of FIG. 1. Accordingly, in the following description of the example of FIG. 2, reference will be made to Figure 2 the example of FIG. 1. Figure 1 An example of an antenna control circuit 50 is shown. The antenna control circuit 50 can correspond to Figure 1 the antenna control circuit 13 in the example of FIG. 1. Accordingly, in the following description of the example of FIG. 2, reference will be made to Figure 2 the example of FIG. 1. Figure 1 An example of an antenna control circuit 50 is shown. The antenna control circuit 50 can correspond to Figure 1 the antenna control circuit 13 in the example of FIG. 1. Accordingly, in the following description of the example of FIG. 2, reference will be made to Figure 2 the example of FIG. 1. Figure 1 An example of an antenna control circuit 50 is shown. The antenna control circuit 50 can correspond to Figure 1 the antenna control circuit 13 in the example of FIG. 1. Accordingly, in the following description of the example of FIG. 2, reference will

[0034] Antenna control circuit 50 in Figure 2 The example is shown as including a first signal path 52 and a second signal path 54, each corresponding to a separate signal diversity type, as described in more detail herein. Additionally, antenna control circuitry 50 is communicatively coupled to an antenna system (e.g., antenna system 14) via a first transmission line cable 56 and a second transmission line cable 58, the first transmission line cable being configured to propagate signal TS1 between the antenna system and antenna control circuitry 50, and the second transmission line cable being configured to propagate signal TS2 between the antenna system and antenna control circuitry 50. For example, transmission line cables 56 and 58 may be connected to a calibration circuit (e.g., calibration circuitry 20) coupled to the antenna system. Transmission line cables 56 and 58 may each be associated with a corresponding signal diversity type, and thus with a corresponding signal path of antenna control circuitry 50. For example, transmission line cables 56 and 58 may be configured as RG6 cables or other types of transmission line cables.

[0035] exist Figure 2 In the example, antenna control circuitry 50 includes a first amplitude adjustment circuitry 60 provided in a first signal path 52 and a second amplitude adjustment circuitry 62 provided in a second signal path 54. As an example, amplitude adjustment circuits 60 and 62 may each include at least one variable circuit element (VCE) in the respective signal paths 52 and 54. For example, the VCE may be configured as a variable attenuator, a variable gain amplifier, and / or a fixed gain amplifier. As described in more detail herein, amplitude adjustment circuits 60 and 62 may provide amplification (e.g., attenuation) of signals TS1 and TS2. As described herein, the term "amplification" may refer to adjusting signals TS1 and TS2 using positive or negative gain. As an example, the gain may be set to zero as a bypass condition (e.g., for received signals TS1 and TS2). Figure 2 In the example, signals TS1 and TS2 are provided to the corresponding amplitude adjustment circuits 60 and 62 through the first switch SW1 and the second switch SW2, respectively.

[0036] exist Figure 2 In the example, antenna control circuit 50 includes a power supply block 64 that interconnects amplitude adjustment circuits 60 and 62 with transmission line cables 56 and 58. Power supply block 64 is configured to generate or receive a DC voltage V. DC As an example, voltage V DC It can have an amplitude that varies between normal operating mode and calibration mode. For example, power block 64 can be configured as a low dropout (LDO) regulator, such as generating a DC voltage V from a higher input voltage. DC Power supply block 64 provides DC voltage V to the first injection circuit 66 and the second injection circuit 68. DCFor example, the injection circuits 66 and 68 can be configured as biasers. The injection circuits 66 and 68 are each coupled to the transmission line cables 56 and 58 over which the transmit and receive signals TS1 and TS2 propagate, respectively. Thus, the injection circuits 66 and 68 are configured to inject a DC voltage V DC to the antenna system for controlling associated electronics (e.g., switches) in the antenna system.

[0037] The antenna control circuit 50 also includes a transmission line measurement circuit 70. The transmission line measurement circuit 70 is configured to determine signal loss between the user communication system and the antenna control circuit 50 over the transmission line cables 56 and 58. For example, the transmission line measurement circuit 70 can initiate a calibration operation in response to a calibration command CAL periodically during and / or after installation of the associated antenna system. As one example, the calibration command CAL can be provided in response to a user input such as via a physical input (e.g., a physical button or a button on a touch screen) on the antenna control circuit 50 or the calibration system 20, in response to power-up of the antenna control circuit 50 (e.g., in response to initial receipt of the voltage V DC while automatically provided), from a processor or controller device periodically (e.g., at periodic or programmable intervals), or from any of a variety of other means. As another example, the calibration command CAL can be initiated in response to a change in the DC voltage V DC , or can be initiated via tone signaling on the signals TS1 and TS2.

[0038] In the example of Figure 2 , the transmission line measurement circuit 70 includes a calibration signal generator 72, a signal monitor 74, and a memory 76. The transmission line measurement circuit 70 is communicatively coupled to the first amplitude adjustment circuit 60 through a first switch SW1 and to the second amplitude adjustment circuit 62 through a second switch SW2. In the example of Figure 2 , the switches SW1 and SW2 are shown set to a normal operating mode state and are controlled via the calibration command CAL. Thus, in the normal operating mode, as Figure 2In the state shown in the example of FIG. 1, switch SW1 connects first amplitude adjustment circuit 60 to first signal path 52 to receive signal TS1, and switch SW2 connects second amplitude adjustment circuit 62 to second signal path 54 to receive signal TS2. Thus, in the normal mode of operation, switches SW1 and SW2 can facilitate the propagation of transmit and receive signals between the user communication system and the antenna system via respective signal paths 52 and 54 and respective transmission line cables 56 and 58. However, in a calibration mode, such as initiated by calibration command CAL, switches SW1 and SW2 can be switched to couple amplitude adjustment circuits 60 and 62 to transmission line measurement circuit 70 to facilitate calibration operations.

[0039] During calibration operations, calibration signal generator 72 can be configured to generate a calibration signal, such as a virtual RF signal having a predefined frequency. In the example of FIG. 1, calibration signal generator 72 is shown as generating calibration signals CS1 and CS2 corresponding to first and second transmission line cables 56 and 58, respectively, via amplitude adjustment circuits 60 and 62. Thus, transmission line measurement circuit 70 can transmit one or both of calibration signals CS1 and CS2 to the antenna system via a respective one of transmission line cables 56 and 58. Figure 3

[0040] The antenna system can be configured to retransmit calibration signals CS1 and / or CS2 as respective return signals from the antenna system back to antenna control circuit 50 via transmission line cables 56 and 58 during the calibration process. In response to receiving the return signals, signal monitor 74 can be configured to measure at least one characteristic of the return signals to determine signal losses exhibited by transmission line cables 56 and 58. For example, the characteristic of the return signals can be power, such that signal monitor 74 can calculate a power ratio between one of calibration signals CS1 and CS2 and the respective return signal. Thus, signal monitor 74 can determine signal losses exhibited by transmission line cables 62 and 64 based on the power ratio between calibration signals CS1 and CS2 and the respective return signal. Additionally, other types of characteristics, such as delay time, can be monitored as an alternative or in addition to power to determine signal losses exhibited by transmission line cables 62 and 64. Transmission line measurement circuit 70 can then store the determined signal losses in memory 76. For example, memory 76 can store signal loss information for both transmission line cables 56 and 58, individually or in combination, and can store signal loss information for each calibration operation or the most recent calibration operation. As one example, memory 76 can be configured as a non-volatile memory, such that memory 76 can retain signal loss information calculated during power loss of antenna control circuit 50. Thus, the calculated signal losses can be retrieved from memory 76 after power is returned to antenna control circuit 50 to facilitate operation of antenna control circuit 50 without requiring calibration operations. ​

[0041] Figure 4 and Figure 3 Exemplary schematic diagrams 100 and 150 of calibration of a communication system are shown, respectively. In the example of schematic diagram 100, the communication system includes a calibration circuit 102 and an antenna control circuit 104 communicatively coupled by a first transmission line cable 106 and a second transmission line cable 108. In the example of schematic diagram 150, the communication system includes a calibration circuit 152 and an antenna control circuit 154 communicatively coupled by a first transmission line cable 156 and a second transmission line cable 158. Figure 4 Figure 3 Figure 4 and Figure 1 The calibration circuits in the examples of Figure 3 may each correspond to the calibration circuit 20 in the example of Figure 4 and Figure 1 the following description of the examples of Figure 2 and Figure 5 the examples of

[0042] In schematic diagram 100, the antenna control circuit 104 includes a transmission line measurement circuit 110. During a calibration operation, the transmission line measurement circuit 110 can be configured to generate a first calibration signal CS1 (e.g., via the calibration signal generator 72), which is launched by the transmission line measurement circuit 110 along the first transmission line cable 106. The calibration circuit 102 can be configured to retransmit (e.g., reflect) the calibration signal CS1 as a respective return signal RTN1 back to the antenna control circuit 104 via the first transmission line cable 106. Thus, in schematic diagram 100, the first transmission line 106 is configured to propagate both the calibration signal CS1 and the reflected return signal RTN1. In response to receiving the return signal RTN1, the transmission line measurement circuit 110 can be configured to measure the at least one characteristic of the reflected return signal RTN1 (e.g., via the signal monitor 74) to determine a signal loss exhibited by the first transmission line cable 106. For example, the characteristic of the reflected return signal RTN1 can be power, such that the transmission line measurement circuit 110 can calculate a power ratio between the calibration signal CS1 and the respective reflected return signal RTN1 to determine the signal loss exhibited by the first transmission line cable 106.

[0043] ​​Similarly, the transmission line measurement circuit 110 can repeat the calibration process previously described with respect to the second transmission line cable 108. For example, the transmission line measurement circuit 110 can also be configured to generate a second calibration signal CS2, which is transmitted by the transmission line measurement circuit 110 along the second transmission line cable 108. The calibration circuit 102 can be configured to retransmit (e.g., reflect) the calibration signal CS2 as a respective return signal RTN2 back to the antenna control circuit 104 via the second transmission line cable 108. In response to receiving the reflected return signal RTN2, the transmission line measurement circuit 110 can be configured to measure (e.g., via the signal monitor 74) the at least one characteristic of the reflected return signal RTN2 to determine the signal loss exhibited by the second transmission line cable 108, similar to that previously described with respect to the first transmission line cable 106.

[0044] In diagram 150, the antenna control circuit 154 includes a transmission line measurement circuit 160. During a calibration operation, the transmission line measurement circuit 160 can be configured to generate (e.g., via the calibration signal generator 72) a first calibration signal CS1, which is transmitted by the transmission line measurement circuit 160 along the first transmission line cable 156. The calibration circuit 152 can be configured to retransmit the calibration signal CS1 as a respective return signal RTN1 back to the antenna control circuit 154 via the second transmission line cable 158. Thus, in diagram 150, the first transmission line 156 is configured to propagate the calibration signal CS1, and the second transmission line cable 158 is configured to propagate the return signal RTN1. In response to receiving the return signal RTN1, the transmission line measurement circuit 160 can be configured to measure (e.g., via the signal monitor 74) the at least one characteristic of the return signal RTN1 to determine the signal loss exhibited by the first transmission line cable 156 and the second transmission line cable 158. For example, the characteristic of the return signal RTN1 can be power, such that the transmission line measurement circuit 160 can calculate a power ratio between the calibration signal CS1 and the respective return signal RTN1 to determine the signal loss exhibited by the first transmission line cable 156 and the second transmission line cable 158. As one example, the transmission line measurement circuit 160 can either end the calibration operation or repeat the calibration process previously described with respect to switching the first transmission line cable 156 and the second transmission line cable 158 with respect to the transmission of the calibration signal CS and the reception of the return signal RTN.

[0045] Figure 1 An example of an antenna system 200 is shown. The antenna system 200 can correspond to the antenna system 14 of the example of Figure 5 the example of the following description will refer to the example of Figure 1 the example of the following description will refer to the example of Figure 1 the example of the following description will refer to the example of

[0046] The antenna system 200 comprises a first antenna array 202 and a second antenna array 204, which can each be associated with a respective signal diversity type. The antenna arrays 202 and 204 can be arranged as any one of a variety of antenna arrays to provide a respective one or more wireless signals to be transmitted from and / or received at the antenna system 200, which are shown as respective signals RF1 and RF2. For example, the antenna arrays 202 and 204 can comprise an arrangement of antenna elements (e.g., stripline conductors) to provide signal diversity between two respective signal paths, such as based on polarization diversity. As one example, the antenna arrays 202 and 204 can be configured as separate respective arrays of orthogonally polarized antenna elements to provide orthogonal polarization of signals propagating in the respective signal paths. The antenna arrays 202 and 204 can each thus transmit and receive signals in a TDD manner based on defined standards for user communication system operation.

[0047] The antenna system 200 further comprises a calibration circuit 205, such as the calibration circuit 20 in the example of Figure 5 The calibration circuit 205 comprises an extraction circuit 206, which can be configured to be coupled to a DC decoupler (e.g., a bias tee) of the transmission line cables 56 and 58 to extract a DC voltage, such as provided from the power supply block 64 (shown as voltage V DC ), to power electronics of the antenna system 200. For example, the DC voltage V DC may be a DC bias voltage provided on the transmission line cables 56 and 58, such that the extraction circuit 206 extracts the voltage V DC to power electronic components of the antenna system 200. Thus, the antenna system 200 does not require a local power supply, such that the antenna system 200 can be installed in a more flexible manner.

[0048] The calibration circuit 205 comprises a first signal port 208 and a second signal port 210 coupled to the antenna control circuit 50. The first signal port 208 is configured to propagate transmit and receive signals TS1 via the transmission line cable 56, and the second signal port 210 is configured to propagate transmit and receive signals TS2 via the transmission line cable 58. The first signal port 208 is coupled to the first transmission line cable 56 via a first switch SW3 associated with the calibration circuit 205, and the second signal port 210 is coupled to the second transmission line cable 58 via a second switch SW4 associated with the calibration circuit 205. In the example of Figure 2 the switches SW3 and SW4 are shown set to a normal operation mode state, and are controlled via a calibration command CAL. For example, the calibration command CAL can correspond to the same calibration command CAL described in the example of Figure 5 , or can be a different calibration command to be provided during a calibration operation (e.g., facilitated by a change in the DC voltage operated by a user).

[0049] Thus, in a normal mode of operation, as in the state shown in Figure 4 the example, switch SW3 connects first signal port 208 to first transmission line cable 56 and switch SW4 connects second signal port 210 to second transmission line cable 58 to facilitate the propagation of transmit and receive signals between antenna control circuit 50 and antenna system 200 via respective transmission line cables 56 and 58. However, in a calibration mode, such as initiated by calibration command CAL, switches SW3 and SW4 can be switched to provide a short between transmission line cables 56 and 58. Thus, a calibration signal CS1, such as provided in the example of Figure 6 can be provided from first transmission line cable 56 and can be retransmitted as return signal RTN1 along second transmission line cable 58 back to antenna control circuit 50. Thus, with minimal inputs, antenna system 200 can be implemented in a calibration operation to determine signal losses of transmission line cables 56 and 58.

[0050] Figure 1 An example of an antenna system 230 is shown. Antenna system 230 can correspond to antenna system 14 of the example of Figure 6 Thus, in the following description of the example of Figure 1 the example of Figure 1 will be referred to.

[0051] Antenna system 230 includes first and second antenna arrays 232 and 234 that can each be associated with a respective signal diversity type. Antenna arrays 232 and 234 can be arranged as any one of a variety of antenna arrays to provide a respective one or more wireless signals to be transmitted from and / or received at antenna system 230, shown as respective signals RF1 and RF2. For example, antenna arrays 232 and 234 can include an arrangement of antenna elements (e.g., stripline conductors) to provide signal diversity between two respective signal paths, such as based on polarization diversity. As one example, antenna arrays 232 and 234 can be configured as separate respective arrays of orthogonally polarized antenna elements to provide orthogonal polarization of signals propagating in respective signal paths. Thus, antenna arrays 232 and 234 can each transmit and receive signals in a TDD manner based on defined standards of user communication system operation.

[0052] Antenna system 230 also includes calibration circuit 235, such as corresponding to calibration circuit 20 in the example of Figure 5 Calibration circuit 235 includes extraction circuit 236 that can be configured as a DC decoupler (e.g., a bias tee) coupled to transmission line cables 56 and 58 to extract a DC voltage, such as provided from power supply block 64, shown as voltage V DCto power the electronics of the antenna system 230. For example, a DC voltage V DC The DC bias voltage provided on the transmission line cables 56 and 58 can be such that the extraction circuit 236 extracts the voltage V DC to power the electronic components of the antenna system 230. Thus, the antenna system 230 does not require a local power supply, enabling a more flexible way of installing the antenna system 230.

[0053] The antenna system 230 comprises a first signal port 238 and a second signal port 240 coupled to the antenna control circuit 50. The first signal port 238 is configured to propagate transmit and receive signals TS1 via the transmission line cable 56, and the second signal port 240 is configured to propagate transmit and receive signals TS2 via the transmission line cable 58. The first signal port 238 is coupled to the first transmission line cable 56 via a first switch SW3 associated with the calibration circuit 235, and the second signal port 240 is coupled to the second transmission line cable 58 via a second switch SW4 associated with the calibration circuit 235. In Figure 2 In the example of Fig. 2, the switches SW3 and SW4 are shown set to a normal operation mode state, and are controlled via a calibration command CAL. For example, the calibration command CAL can correspond to Figure 6 the same calibration command CAL described in the example of Fig. 2, or can be a different calibration command to be provided during a calibration operation (e.g., facilitated by a user).

[0054] Thus, in the normal operation mode, as in the state shown in Figure 3 the example of Fig. 2, the switch SW3 connects the first signal port 238 to the first transmission line cable 56 and the switch SW4 connects the second signal port 240 to the second transmission line cable 58 to facilitate propagation of transmit and receive signals between the antenna control circuit 50 and the antenna system 230 via the respective transmission line cables 56 and 58. However, in a calibration mode, such as initiated by the calibration command CAL, the switches SW3 and SW4 can be switched to couple each of the transmission line cables 56 and 58 to a ground terminal. Thus, a calibration signal CS1 such as provided in the example of Fig. 2 can be provided from the first transmission line cable 56 and can be reflected as a return signal RTN1 along the first transmission line cable 56 back to the antenna control circuit 50. Similarly, a calibration signal CS2 such as provided in the example of Fig. 2 can be provided from the second transmission line cable 58 and can be reflected as a return signal RTN2 along the second transmission line cable 58 back to the antenna control circuit 50. Thus, with minimal input, the calibration circuit 235 can implement in a calibration operation to determine signal losses of the transmission line cables 56 and 58. Figure 3 Figure 7

[0055] Figure 2 ​​An example of a transmission line measurement circuit 250 is shown. The transmission line measurement circuit 250 can correspond to the transmission line measurement circuit 70 in the example of Figure 7 . Thus, in the following description of the example of Figure 2 to Figure 6 , reference will be made to the example of Figure 7 . Thus, in the following description of the example of , reference will be made to the example of

[0056] As previously described, the transmission line measurement circuit 250 is configured to determine a signal loss between an antenna system (e.g., the antenna system 14, or one of the antenna systems 200 and 230) and the antenna control circuit 50 over the transmission line cables 56 and 58. In the example of Figure 7 , the transmission line measurement circuit 250 includes a calibration signal generator 252 and a signal monitor 254. The calibration signal generator 252 includes an RF signal source 256 configured to generate a calibration signal that can correspond to a first calibration signal CS1. As one example, the first calibration signal CS1 can correspond to a virtual RF signal (e.g., a sinusoidal signal) having a predefined frequency. In the example of Figure 4 , the calibration signal generator 252 includes a resistive network 258 including a first resistor R1 and a second resistor R2 each connected to the RF signal source 256 and to a third resistor R3 opposite the RF signal source 256 and interconnecting the first resistor R1 and the second resistor R2. Thus, the resistive network 258 can provide a divided version of the first calibration signal CS1 that can be provided to the first transmission line cable 56 (e.g., via a switch SW1) in a calibration mode. Thus, the transmission line measurement circuit 250 can transmit the calibration signal CS1 to the antenna system via the transmission line cable 56.

[0057] As previously described, the antenna system can be configured to retransmit the calibration signal CS1 as a respective return signal RTN1 from the antenna system back to the antenna control circuit 50 over the transmission line cable 58 during the calibration process, such as described in the example of Figure 7 . In the example of Figure 4 , the return signal RTN1 is provided to the signal monitor 254 via a diode D1. The signal monitor 254 is further configured to receive a divided version of the first calibration signal CS1 via a diode D2, which is shown as a signal CS 1D . Thus, as one example, the signal monitor 254 can be configured to measure a power of each of the return signal RTN1 and the signal CS 1D . Thus, the signal monitor 254 can compute a power ratio between the return signal RTN1 and the signal CS 1D . Thus, the signal monitor 254 can compute a power ratio between the return signal RTN1 and the signal CS 1DThe power ratio between the two lines determines the signal loss exhibited by transmission line cables 56 and 58. Therefore, power monitor 254 can provide the calculated signal loss to memory 76, which is displayed as the signal PWR_LS.

[0058] Although the transmission line measurement circuit 250 is configured to provide Figure 7 The example demonstrates the calibration operation, but it should be understood that the transmission line measurement circuit 250 is not limited to this. Figure 3 Examples. For instance, the transmission line measurement circuit 250 may be arranged in a manner to facilitate the propagation of either the calibration signal CS1 and the return signal RTN1 or the calibration signal CS2 and the return signal RTN2 along one of the transmission line cables 56 and 58, such as... Figure 2 As described in the example.

[0059] See back Figure 2 For example, antenna control circuit 50 also includes controller 78. In response to determining signal loss, transmission line measurement circuit 70 may (e.g., from memory) provide controller 78 with a determined signal loss, which... Figure 2 In the example, it is shown as "SM". In response to a determined signal loss SM, controller 78 can be configured to adjust the amplitude of at least one of a transmitted signal transmitted from antenna control circuit 50 and a received signal received at antenna control circuit 50 based on the determined signal loss. As an example, controller 78 may include a processor configured to determine appropriate adjustments to the amplitude of each of the corresponding transmitted and received signals based on the determined signal loss SM. While controller 78 is described as including a processor, the term "processor" can be used to describe other types of processing devices, such as field-programmable gate arrays (FPGAs), application-specific integrated circuits (ASICs), or other types of processing devices. Figure 2 In the example, controller 78 is configured to provide control signals, shown as “AT1” and “AT2”, to amplitude adjustment circuits 60 and 62, respectively, based on a determined signal loss SM and whether signal paths 54 and / or 56 are in transmit or receive mode.

[0060] For example, the communication system 10 can be configured to operate based on a predetermined communication standard, which can specify a predetermined maximum effective isotropic radiated power (EIRP), such as +23 dBm for a transmit signal. Accordingly, the controller 78 provides control signals AT1 and AT2 to the respective amplitude adjustment circuits 60 and 62 in the transmit mode to attenuate the transmit signal to less than the predetermined maximum EIRP. For example, the antenna arrays 202 and 204 or the antenna arrays 232 and 234 can be designed to have sufficiently high gain to provide a transmit signal at a power level greater than the predetermined maximum EIRP to overcome power losses of the transmission line cables 56 and 58 regardless of the lengths of the transmission line cables 56 and 58, such that the transmit signal can be attenuated to approximately the predetermined maximum EIRP. Additionally or alternatively, the signal paths 52 and 54 can include sufficient power amplification in the transmit mode (as described in greater detail herein) to overcome power losses of the transmission line cables 56 and 58 regardless of the lengths of the transmission line cables 56 and 58, such that the transmit signal can be attenuated to approximately the predetermined maximum EIRP. Similarly, the controller 78 provides control signals AT1 and AT2 to the respective amplitude adjustment circuits 60 and 62 in the receive mode to attenuate the receive signal to less than an acceptable operating level (e.g., a maximum saturation power associated with the antenna control circuit 50 and / or the user communication system 12). Accordingly, the antenna system 14 can be installed in a manner that is substantially agnostic to the lengths and / or loss characteristics of the transmission line cables 56 and 58 to determine the signal losses of the transmission line cables 56 and 58 based on the calibration operation.

[0061] Further, in Figure 2 the example, the controller 78 can also be configured to provide continuous voltage or tone signal monitoring of the transmission line cables 56 and 58 to determine a fault condition and / or a calibration failure. In response to detecting a fault condition and / or a calibration failure, the controller 78 can each assert respective signals FLT1 and FLT2 provided to respective switches SW5 and SW6. The switches SW5 and SW6 can thus terminate the signal paths 52 and 54 to a ground resistor to provide isolation and / or termination of the signal paths 52 and 54 to isolate the antenna system 14 from the user communication device 12 in the event of a fault condition and / or a calibration failure. Such termination of the signal paths 52 and 54 to a load via the switches SW5 and SW6 can also reduce external harmful signal disruption of the calibration. As another example, the controller 78 can instead control isolation or termination switches in the amplitude adjustment circuits 60 and 62, respectively, for isolating and / or terminating the signal paths 52 and 54 in the event of a fault condition and / or a calibration failure.

[0062] In Figure 5 the example, as one example, the controller 78 can provide a calibration voltage VCAL Calibration voltage V CAL Therefore, the voltage V is transmitted to the antenna system 14 via transmission line 58. CAL It can be transmitted via transmission line 56 (e.g., via...) Figure 5 In the example, calibration circuit 205) is provided back to antenna control circuit 50. If controller 78 does not detect voltage V via transmission line 56 CAL (For example, provided from calibration circuit 205), then controller 78 can indicate a fault and / or calibration failure. Thus, controller 78 can monitor the continuity of communication system 10, and in the event of a short circuit or fault / open circuit in transmission lines 56 and 58, controller 78 can remove voltage, thereby automatically terminating antenna system 200 or 230, and can assert fault signals FLT1 and FLT2 to terminate user communication equipment 12.

[0063] See Figure 6 and Figure 2 For example, antenna systems 200 and 230 each include termination switches SW7 and SW8 to terminate antenna arrays 202 and 204 or antenna arrays 232 and 234 in response to fault signals FLT1 and FLT2. As an example, controller 78 can trigger a calibration sequence by applying a voltage or tone signal to transmission lines 56 and 58. Extraction circuits 206 and 236 may also include voltage or tone detection circuitry to switch antenna systems 200 and 230 to a calibration state. During calibration or when voltage V... DC In the event of a fault, antenna systems 200 and 230 can automatically switch antenna arrays 202 and 204 or antenna arrays 232 and 234 to load resistors (e.g., via switches SW7 and SW8) to prevent transmission during fault conditions and reduce external interference and harmful signals from disrupting calibration.

[0064] See again Figure 2 For example, as previously described, communication system 10 can operate based on a TDD communication standard, such that transmitted and received signals can be interleaved on a given signal path between user communication system 12 and antenna arrays 202 and 204 or antenna arrays 232 and 234. Additionally, as previously described, signal paths 52 and 54 of antenna control circuitry 50 can operate in either a transmit mode or a receive mode, corresponding to the transmission of transmitted signals or the reception of received signals in a TDD manner along the respective signal paths 52 and 54. Figure 2 In the example, the antenna control circuit 50 also includes a first transmit detection circuit 80 associated with the first signal path 52 and a second transmit detection circuit 82 associated with the second signal path 54. The transmit detection circuits 80 and 82 can be configured to measure the power on the respective signal paths 52 and 54 to determine whether the user communication system 12 is transmitting a transmit signal.

[0065] For example, transmit detection circuits 80 and 82 may each include a bidirectional coupler with a terminating load to determine whether the power on a corresponding one of the signal paths 52 and 54 is greater than a predetermined threshold, thereby determining whether the user communication system 12 is transmitting a transmit signal. Figure 8 In the example, transmit detection circuits 80 and 82 are configured to generate mode signals TX1 and TX2 provided to controller 78, such as to indicate that a corresponding one of signal paths 52 and 54 is in transmit mode. Therefore, in response to transmit detection circuits 80 and 82 determining whether user communication system 12 is transmitting a transmit signal, controller 78 can switch the corresponding signal paths 52 and 54 from receive mode (which is the default mode) to transmit mode to facilitate the transmission of the transmit signal from antenna control circuit 50 via antenna arrays 202 and 204 or antenna arrays 232 and 234. Similarly, in response to transmit detection circuits 80 and 82 detecting a decrease in the power of a signal path (e.g., less than a predetermined threshold), controller 78 can switch the corresponding signal paths 52 and 54 back from transmit mode to receive mode (e.g., when a timer expires).

[0066] As previously described, controller 78 can be configured to adjust corresponding control signals AT1 and AT2 based on an indication of the transmission or reception mode of a corresponding one of signal paths 52 and 54 (such as based on corresponding mode signals TX1 and TX2). Therefore, the amplitudes of the transmitted and received signals can be adjusted (e.g., attenuated) based on whether the corresponding signal path 52 or 54 is in transmission or reception mode. As another example, as previously described, amplitude adjustment circuits 60 and 62 can be switched between the transmission mode signal path and the reception mode signal path of each of amplitude adjustment circuits 60 and 62 via a switch. Therefore, controller 78 may also include a switch controller 84 configured to control the switching of amplitude adjustment circuits 60 and 62.

[0067] As one example, the switch controller 84 can be configured to generate mode signals MD1 and MD2 to control the mode of a respective one of the signal paths 52 and 54. For example, the amplitude adjustment circuit 60 can be controlled by the first switch signal MD1 and the amplitude adjustment circuit 62 can be controlled by the second switch signal MD2. In response to one of the transmit detection circuits 80 and 82 determining that the user communication system 12 is transmitting one transmit signal along a respective one of the signal paths 52 and 54, the respective one of the transmit detection circuits 80 and 82 commands the controller 78 to provide the respective one of the switch signals MD1 and MD2 to the respective one of the amplitude adjustment circuits 60 and 62 (e.g., via the mode signals TX1 and TX2). In response to the respective one of the switch signals MD1 and MD2, the respective amplitude adjustment circuit 60 and 62 can activate at least one switch to switch the respective amplitude adjustment circuit 60 or 62 from a default receive mode to a transmit mode, thereby facilitating transmission of the transmit signal along the respective signal path 52 and 54 and from the respective antenna array 58 and 60.

[0068] Figure 2 An example of a controller 300 is shown. The controller 300 can correspond to Figure 8 the controller 78 in the example of Figure 2 the example of Figure 8 the example.

[0069] The controller 300 includes a processor 302. For example, the processor 302 can be in communication with, or include, the amplitude adjustment circuits 60 and 62. In the example of Figure 7 the processor 302 receives a signal SM corresponding to signal loss of the transmission line cables 56 and 58. Accordingly, the processor 302 can be configured to calculate an appropriate amount of amplification (e.g., attenuation) to provide to the amplitude adjustment circuits 60 and 62, such as to provide appropriate attenuation to the signal paths 52 and / or 54 based on a respective mode (e.g., a transmit mode or a receive mode). In the example of Figure 2 the processor 302 is shown generating control signals AT1 and AT2 to provide to the amplitude adjustment circuits 60 and 62, such as to provide appropriate attenuation to the signal paths 52 and / or 54 based on a respective mode.

[0070] As previously described, Figure 8 the controller 78 in the example of Figure 8In the example of FIG. 3, the controller 300 can include a switching controller 304 that can provide a switching signal MD for one of the amplitude adjustment circuits 60 and 62. Thus, it should be understood that the controller 300 can include a switching controller 304 for each of the signal paths 52 and 54. The switching controller 304 includes a first comparator 306 and a second comparator 308. The first comparator 306 is configured to compare a voltage V RX corresponding to an approximate power of the receive signal to a threshold voltage V RX_TH . Similarly, the second comparator 308 is configured to compare a voltage V TX corresponding to an approximate power of the transmit signal to a threshold voltage V TX_TH . As one example, the voltages V RX and V TX may correspond to the same voltage (e.g., corresponding to a signal power on a given one of the signal paths 52 and 54 as measured by the transmit detection systems 90 and 92). Thus, the comparators 306 and 308 can be configured to provide an asserted output corresponding to a mode of the respective signal path 52 or 54.

[0071] The switching controller 304 includes a first sequence of D-latches (e.g., flip-flops) shown as 310, 312, and 314. The first D-latch 310 receives an output of the first comparator 306 as an input, where the D-latches 310, 312, and 314 are configured in a cascaded arrangement from output to input. Each of the D-latches 310, 312, and 314 receives a clock signal CLK from an oscillator 316. Outputs of the second D-latch 312 and the third D-latch 314 are provided as inputs to an AND gate 318, where the input received from the third D-latch 314 is inverted. In a similar arrangement, the switching controller also includes a second sequence of D-latches shown as 320, 322, and 324. The first D-latch 320 receives an output of the second comparator 308 as an input, where the D-latches 320, 322, and 324 are configured in a cascaded arrangement from output to input. Each of the D-latches 320, 322, and 324 likewise receives the clock signal CLK. Outputs of the second D-latch 322 and the third D-latch 324 are provided as inputs to an AND gate 326, where the input received from the third D-latch 324 is inverted.

[0072] An output of the AND gate 318 is provided as a set input to an SR latch 328, and an output of the AND gate 326 is provided as a reset input to the SR latch 328. The SR latch 328 likewise receives the clock signal CLK and is configured to generate a respective switching signal MD (e.g., one of the switching signals MD1 and MD2). Thus, the SR latch 328 is configured to assert the switching signal MD in response to the voltage V TX and / or VRX The state of the switching signal MD changes rapidly due to amplitude variations. For example, in response to voltage V... TX and / or V RX The amplitude variation, the logic sequence of D latches 310, 312, 314, 320, 322 and 324, AND gates 318 and 326 and SR latch 328 can be configured to change the state of the switching signal MD in about 10 microseconds or less, such as to meet TDD communication standards.

[0073] Processor 302 can be configured to receive multiple inputs associated with the switching logic of switching controller 304. Figure 8 In the example, processor 302 receives the outputs of D latches 314 and 324 and the outputs of AND gates 318 and 326 as inputs. For example, processor 302 may be configured as a state machine to monitor the state of a signal path (e.g., signal path 52 or 54), such that the inputs of processor 302 are configured to set flags and / or registers for the operation of antenna control circuitry 50. As another example, oscillator 316 may be included in processor 302, causing processor 302 to generate a clock signal CLK. Additionally, processor 302 is shown to generate a predetermined threshold voltage V. TX_TH and V RX_TH These predetermined threshold voltages can be programmed via inputs to the processor 302, or they can have a fixed voltage amplitude.

[0074] exist Figure 9 In the example, processor 302 includes timer 330 (e.g., one for each of signal paths 52 and 54). As an example, timer 330 may correspond to a watchdog timer to control timing associated with mode selection of the respective signal paths 52 and 54. For example, in response to an input indication provided to processor 302, a mode is set for the transmission mode of a given one of signal paths 52 and 54, but the transmission power is less than a predetermined threshold (e.g., voltage V). TX Less than a predetermined threshold V TX_TH), the corresponding timer 330 can begin counting a predetermined timing threshold. As one example, in response to the corresponding timer 330 counting within a predetermined duration (e.g., approximately one millisecond), the processor 302 can switch back to a default receive mode for the given signal path 52 or 54, such as to change an amplitude of a corresponding one of the control signals AT1 and AT2. Additionally, the processor 302 can assert an output to the SR latch 328 (e.g., to a "clear" input of the SR latch 328). Thus, the SR latch 328 can reset to change a state of the switch signal MD to indicate switching the mode from a transmit mode back to a receive mode. Thus, the signal path 52 and / or 54 can return to a default receive mode in response to a timing indication that the transmit signal is no longer being transmitted from the user communication system 12.

[0075] To meet a given TDD communication standard, the control signals AT1 and AT2 and the amplitude adjustment circuits 60 and 62 can be required to switch between transmit and receive modes as soon as possible. Figure 9 An exemplary schematic 350 of a TDD communication flow is shown. The TDD communication flow includes a first set of receive signal subframes shown at 352, a first set of transmit signal subframes shown at 354, and a second set of receive mode subframes 356. As one example, the TDD communication flow can continue with alternating sets of transmit signal subframes and receive signal subframes in a TDD manner. The transmit signal subframes and receive signal subframes are shown in Figure 9 The elements of the time domain shown in the example of Figure 9 The elements of the time domain shown in the example of

[0076] In the example of Figure 9 In the example of INT In the example of INT may correspond to a substantially maximum intermediate time between propagation of the receive signal subframes and the transmit signal subframes on the given signal path, such as between the user communication system 12 and a corresponding one of the antenna arrays 202 or 204, along the transmission line cable 56 or 58, along the corresponding signal path 52 or 54 in the antenna control circuit 50, such as defined by a predetermined TDD communication standard.

[0077] In the example of Figure 10 to Figure 15 In the example of INTA first portion of time 358 and a second portion of time 360 are included. The first portion of time 358 can correspond to a switching time (e.g., approximately 10 microseconds or less), such as to generate appropriate switching signals MD1 and MD2 and / or to activate respective switches of the amplitude adjustment circuits 60 and 62. The second portion of time 360 can correspond to a switching settling time (e.g., also approximately 10 microseconds or less), such as a time for respective switches to settle to a saturation region and / or to eliminate parasitic effects (e.g., capacitance and / or inductance) of circuit components of the switching controller 304 and / or respective amplitude adjustment circuits 60 and 62. Accordingly, the hardware-based logic circuit of the switching controller 304 can enable rapid state changes of the switching signals MD1 and MD2 to satisfy rapid switching requirements specified by TDD communication standards.

[0078] Figure 10 Examples of amplitude adjustment circuits are shown. Figure 11 Examples of amplitude adjustment circuits 370, Figure 12 Examples of amplitude adjustment circuits 400, Figure 13 Examples of amplitude adjustment circuits 450, Figure 14 Examples of amplitude adjustment circuits 500, Figure 15 Examples of amplitude adjustment circuits 550, and Figure 2 Examples of amplitude adjustment circuits 600. Any of the amplitude adjustment circuits 370, 400, 450, 500, 550, and 600 can correspond to Figure 10 to Figure 15 the amplitude adjustment circuits 60 and 62 in the example of Figure 2 the amplitude adjustment circuits 370, 400, 450, 500, 550, and 600 will be referred to with reference to Figure 10 to Figure 15 the example of

[0079] Additionally, the amplitude adjustment circuits 370, 400, 450, 500, 550, and 600 are not limited to the examples shown in the example of Figure 10 to Figure 15 For example, the amplitude adjustment circuits 370, 400, 450, 500, 550, and 600 can include filters, such as low noise filters, bandpass filters, and / or the like, which can be disposed in respective transmit paths, receive paths, or both. As another example, in the example of Figure 10The amplitude adjustment circuits 370, 400, 450, 500, 550, and 600 described in the examples are not limited to providing amplification in each of the transmit and receive paths, but can include a signal bypass path (e.g., zero gain) in either the transmit or receive path. As another example, each of the amplitude adjustment circuits 370, 400, 450, 500, 550, and 600 can include an isolation or termination switch (not shown), such as controlled via the transmit detection circuits 80 and 82, to provide isolation and / or termination of the respective signal paths 52 and 54 to isolate the antenna system 14 from the user communication device 12 in the event of a fault condition and / or calibration failure. Further, the switches described in the amplitude adjustment circuits 400, 450, 500, 550, and 600 can be implemented as transistor devices, such as to provide very fast switching times between transmit and receive modes.

[0080] In Figure 11 In the example of the amplitude adjustment circuit 370, the amplitude adjustment circuit 370 includes a VCE 372 in the signal path (e.g., the signal path 52 or 54). The VCE 372 is shown as being controlled by the control signal AT (e.g., one of the control signals ATI or AT2). For example, the VCE 372 can be configured as a variable attenuator that is controlled by the controller 78 to provide attenuation of the transmit signal in the transmit mode and attenuation of the receive signal in the receive mode (e.g., based on the respective one of the mode signals TX1 or TX2). Thus, the mode of the amplitude adjustment circuit 370 is controlled by the amount of adjustment (e.g., attenuation) provided by the control signal AT in each of the transmit and receive modes.

[0081] In Figure 11 In the example of the amplitude adjustment circuit 400, the amplitude adjustment circuit 400 includes a VCE 401 in the signal path (e.g., the signal path 52 or 54). The VCE 401 is shown as being controlled by the control signal AT (e.g., one of the control signals ATI or AT2). For example, the VCE 401 can be configured as a variable attenuator that is controlled by the controller 78 to provide attenuation of the transmit signal in the transmit mode and attenuation of the receive signal in the receive mode (e.g., based on the respective one of the mode signals TX1 or TX2). The amplitude adjustment circuit 400 further includes a first switch SW5, a second switch SW6, and a third switch SW7 each controlled by the switching signal MD. The switches SW5, SW6, and SW7 are shown in a default state corresponding to a default state of the receive mode. The first switch SW5 and the second switch SW6 are each in a first state in the transmit mode and in a second state in the receive mode. The third switch SW7 is in the first state in the transmit mode and in the second state in the receive mode. Figure 11 In the example of the amplitude adjustment circuit 400, the amplitude adjustment circuit 400 includes a VCE 401 in the signal path (e.g., the signal path 52 or 54). The VCE 401 is shown as being controlled by the control signal AT (e.g., one of the control signals ATI or AT2). For example, the VCE 401 can be configured as a variable attenuator that is controlled by the controller 78 to provide attenuation of the transmit signal in the transmit mode and attenuation of the receive signal in the receive mode (e.g., based on the respective one of the mode signals TX1 or TX2). The amplitude adjustment circuit 400 further includes a first switch SW5, a second switch SW6, and a third switch SW7 each controlled by the switching signal MD. The switches SW5, SW6, and SW7 are shown in a default state corresponding to a default state of the receive mode. The first switch SW5 and the second switch SW6 are each in a first state in the transmit mode and in a second state in the receive mode. The third switch SW7 is in the first state in the transmit mode and in the second state in the receive mode. Figure 12In the example of FIG. 4, the first signal path 402 can correspond to a receive mode, and the second signal path 404 can correspond to a transmit mode. The second signal path 404 includes a power amplifier 406 configured to amplify a transmit signal in the transmit mode. In addition, the amplitude adjustment circuit 400 includes a low noise amplifier (LNA) 408 arranged in parallel with a third switch SW7 (arranged as a single-pole, single-throw switch). Thus, in the receive mode, a receive signal is amplified by the LNA 408, and in the transmit mode, the transmit signal is provided in a bypass short through the closed switch SW7.

[0082] In Figure 11 In the example of FIG. 4, the first signal path 402 can correspond to a receive mode, and the second signal path 404 can correspond to a transmit mode. The second signal path 404 includes a power amplifier 406 configured to amplify a transmit signal in the transmit mode. In addition, the amplitude adjustment circuit 400 includes a low noise amplifier (LNA) 408 arranged in parallel with a third switch SW7 (arranged as a single-pole, single-throw switch). Thus, in the receive mode, a receive signal is amplified by the LNA 408, and in the transmit mode, the transmit signal is provided in a bypass short through the closed switch SW7. Figure 13 In the example of FIG. 4, the first signal path 402 can correspond to a receive mode, and the second signal path 404 can correspond to a transmit mode. The second signal path 404 includes a power amplifier 406 configured to amplify a transmit signal in the transmit mode. In addition, the amplitude adjustment circuit 400 includes a low noise amplifier (LNA) 408 arranged in parallel with a third switch SW7 (arranged as a single-pole, single-throw switch). Thus, in the receive mode, a receive signal is amplified by the LNA 408, and in the transmit mode, the transmit signal is provided in a bypass short through the closed switch SW7.

[0083] In Figure 13In the example, amplitude adjustment circuit 500 includes VCE 501 in a signal path (e.g., signal path 52 or 54). VCE 501 is shown as being controlled by a control signal AT (e.g., one of control signals AT1 or AT2). For example, VCE 501 may be configured as a variable attenuator controlled by controller 78 to provide attenuation of the transmitted signal in transmit mode and attenuation of the received signal in receive mode (e.g., based on a corresponding one of mode signals TX1 or TX2). Amplitude adjustment circuit 500 also includes switch SW5 and circulator 502. Switch SW5 is arranged as a single-pole double-throw switch controlled by switching signal MD and is shown in a default state corresponding to the default state of receive mode. Switch SW5 selects between a first signal path shown at 504 and a second signal path shown at 506. Figure 14 In the example, the first signal path 504 may correspond to a transmit mode, and the second signal path 506 may correspond to a receive mode. The first signal path 504 includes a power amplifier 508 configured to amplify the transmit signal in transmit mode, thus outputting from the amplitude adjustment circuit 500 via a circulator 502 (which is also arranged as a "clockwise" circulator). The second signal path 506 includes an LNA 510, such that the circulator 502 provides the receive signal on the second signal path 506 in receive mode for amplification by the LNA 510 and output from the amplitude adjustment circuit 500 via a switch SW5.

[0084] exist Figure 14 In the example, amplitude adjustment circuit 550 includes VCE 551 in a signal path (e.g., signal path 52 or 54). VCE 551 is shown as being controlled by a control signal AT (e.g., one of control signals AT1 or AT2). For example, VCE 551 may be configured as a variable attenuator controlled by controller 78 to provide attenuation of the transmitted signal in transmit mode and attenuation of the received signal in receive mode (e.g., based on a corresponding one of mode signals TX1 or TX2). Amplitude adjustment circuit 550 also includes switch SW5 and circulator 552. Switch SW5 is arranged as a single-pole double-throw switch controlled by switching signal MD and is shown in a default state corresponding to the default state of receive mode. Switch SW5 selects between a first signal path shown at 554 and a second signal path shown at 556. Figure 15In the example of FIG. 6, the first signal path 554 can correspond to the transmit mode, and the second signal path 556 can correspond to the receive mode. The first signal path 554 is shown as a bypass short to output the transmit signal from the amplitude adjustment circuit 550 via the circulator 552 (which is also arranged as a “clockwise” circulator). The second signal path 556 includes the LNA 558, such that the circulator 552 provides the receive signal on the second signal path 556 for amplification by the LNA 558 and output from the amplitude adjustment circuit 550 via the switch SW5 in the receive mode.

[0085] In the example of FIG. 6, the first signal path 554 can correspond to the transmit mode, and the second signal path 556 can correspond to the receive mode. The first signal path 554 is shown as a bypass short to output the transmit signal from the amplitude adjustment circuit 550 via the circulator 552 (which is also arranged as a “clockwise” circulator). The second signal path 556 includes the LNA 558, such that the circulator 552 provides the receive signal on the second signal path 556 for amplification by the LNA 558 and output from the amplitude adjustment circuit 550 via the switch SW5 in the receive mode. Figure 10 In the example of FIG. 6, the first signal path 554 can correspond to the transmit mode, and the second signal path 556 can correspond to the receive mode. The first signal path 554 is shown as a bypass short to output the transmit signal from the amplitude adjustment circuit 550 via the circulator 552 (which is also arranged as a “clockwise” circulator). The second signal path 556 includes the LNA 558, such that the circulator 552 provides the receive signal on the second signal path 556 for amplification by the LNA 558 and output from the amplitude adjustment circuit 550 via the switch SW5 in the receive mode.

[0086] Figure 14 , Figure 15 and Figure 11 to Figure 13 The example of FIG. 6 does not include a power amplifier to provide amplification of the transmit signal in the transmit mode. As previously described, the signal paths 52 and 54 can include sufficient power amplification in the transmit mode (such as provided in the example of FIG. 5) to overcome the power losses of the transmission line cables 56 and 58 regardless of the lengths of the transmission line cables 56 and 58 (e.g., to attenuate the transmit signal all the way to approximately the predetermined maximum EIRP). As another example, the signal paths 52 and 54 can include sufficient power amplification in the transmit mode (such as provided in the example of FIG. 4) to overcome the power losses of the transmission line cables 56 and 58 regardless of the lengths of the transmission line cables 56 and 58 (e.g., to attenuate the transmit signal all the way to approximately the predetermined maximum EIRP). Figure 10 , Figure 14 , Figure 15 and Figure 9 The respective amplitude adjustment circuits 370, 550, and 600 in the examples of FIGS. 3, 5, and 6, respectively, can be implemented when the user communication system 12 includes sufficient power amplification of the transmit signal such that a power amplifier is not needed in the transmit signal path. Additionally or alternatively, the antenna arrays 202 and 204 or the antenna arrays 232 and 234 can be designed to have sufficient gain such that power amplification of the transmit signal is not needed in the transmit signal path, thereby providing the feasibility of the amplitude adjustment circuits 550 and 600.

[0087] As another example, the amplitude adjustment circuits 400, 450, and 500 can be implemented so as to install the antenna system 14 in a manner that is completely agnostic to the user communication system 12. For example, during a calibration process, in addition to measuring the signal loss of the transmission line cables 56 and 58, the antenna control circuit 50 can measure the output power of the transmit signal provided from the user communication system 12 (e.g., via the transmit detection circuits 80 and 82, such as relative to a plurality of thresholds). Accordingly, in response to determining the output power of the user communication system 12, the antenna control circuit 50 can appropriately attenuate the transmit signal in the transmit mode all the way down to approximately the predetermined maximum EIRP.

[0088] Accordingly, the switch controller 304 can respond to a change in the amplitude of the voltage V TX and / or V RX such as in response to the transmit detection circuits 80 and 82 detecting a change in power on the respective signal paths 52 and 54. Accordingly, the switch signals MD1 and MD2 can provide fast enough switching to satisfy a maximum switching time (e.g., a first portion 558 of the time in the example of FIG. 6), thereby complying with TDD communication standards. Accordingly, the antenna control circuit 50 can operate to facilitate bi-directional TDD communication between the transmit signal and the receive signal, such as without requiring communication or signaling from the user communication system 12. Accordingly, the antenna system 14 can be installed in a simple manner that is largely independent of the operation of the user communication system 12. In addition, the antenna system 14 can be installed in a manner that is agnostic to the length of the transmission line cables 56 and 58 that interconnect the antenna control circuit 50 and the user communication system 12. Accordingly, the antenna control circuit 50 can be simply installed to effectively facilitate wireless communication between the user communication system 12 and a network hub (e.g., a base station). Figure 16

[0089] In view of the structural and functional features described above, the methods according to various aspects of the present application will be better understood with reference to Figure 16 While, for purposes of illustrative simplicity, the methods are shown and described as being performed sequentially, it is to be understood and appreciated that the application is not limited by the illustrated ordering as some aspects can occur in different orders and / or concurrently with other aspects from those shown and described herein. Moreover, it is not necessary that all described features be included to implement a methodology in accordance with the application. Figure 16

[0090] ​ ​​An example of a method 650 for communicating at least one of a transmit signal and a receive signal via a TDD antenna communication system (e.g., communication system 10) including an antenna system (e.g., antenna system 14) is shown. At 652, a calibration signal (e.g., calibration signals CS1 and / or CS2) is provided from an antenna control circuit (e.g., antenna control circuit 13) to the antenna system over at least one transmission line cable (e.g., transmission line cable 16). At 654, a return signal (e.g., return signals RTN1 and RTN2) corresponding to the calibration signal is received at the antenna control circuit from the antenna system over the at least one transmission line cable. At 656, a signal loss between the antenna system and the antenna control circuit over the at least one transmission line cable is determined (e.g., via transmission line measurement circuit 22) based on the return signal. At 658, an amplitude of a receive signal received via the at least one transmission line cable is adjusted in a receive mode based on the determined signal loss. At 660, a signal power of a transmit signal obtained from a user communication system via the at least one transmission line cable is monitored (e.g., via transmit detection circuit 28). At 662, an amplitude adjustment circuit (e.g., amplitude adjustment circuit 24) is switched from the receive mode to a transmit mode (e.g., via controller 26) in response to the monitored signal power exceeding a predetermined threshold. At 664, the amplitude of the transmit signal is adjusted in the transmit mode based on the determined signal loss.

[0091] What has been described above are examples of the present application. It is, of course, not possible to describe every conceivable combination of components or methodologies for purposes of describing the present application, but one of ordinary skill in the art will recognize that many further combinations and permutations of the present application are possible. Accordingly, the present application is intended to embrace all such alterations, modifications, and variations that fall within the spirit and scope of the appended claims. Additionally, where the disclosure or claims recite "a," "an," "the" or "another" element, or "at least one" element, these terms are taken to mean one or more than one such element, neither requiring nor excluding the presence of two or more such elements. As used herein, the term "includes" means includes but not limited to, and the term "including" means including but not limited to. The term "based on" means based at least in part on.

Claims

1. An automatic synchronous time division duplex (TDD) antenna communication system, comprising: an antenna system configured to communicate a transmit signal and a receive signal; and an antenna control circuit coupled to a user communication system and the antenna system and at least one transmission line cable, wherein: the antenna system is configured to communicate the transmit signal and the receive signal to and from the user communication system without active control communication between the antenna system and the user communication system, wherein the antenna system is used to facilitate bidirectional time division duplex communication between transmit and receive signals without requiring communication or signaling from the user communication system; the antenna control circuit is coupled to the antenna system via the at least one transmission line cable, and the antenna control circuit comprises: a transmission line measurement circuit configured to determine signal loss between the antenna system and the antenna control circuit over the at least one transmission line cable; an amplitude adjustment circuit configured to adjust an amplitude of at least one of the transmit signal and the receive signal based on the determined signal loss; a transmit detection circuit configured to monitor signal power along a signal path within the antenna control circuit and generate a transmit mode signal based on the signal power; and a controller configured to receive the transmit mode signal from the transmit detection circuit to generate a mode signal and provide the mode signal to the amplitude adjustment circuit to switch the amplitude adjustment circuit from a receive mode to a transmit mode in response to the monitored signal power exceeding a predetermined threshold, the controller being further configured to generate a control signal and provide the control signal to the amplitude adjustment circuit, wherein based on the control signal, in the receive mode the amplitude adjustment circuit applies a receive amplitude adjustment to the receive signal along the signal path, and in the transmit mode the amplitude adjustment circuit applies a transmit amplitude adjustment to the transmit signal along the signal path.

2. The system of claim 1, wherein in the receive mode the amplitude adjustment circuit adjusts the amplitude of the receive signal obtained via the at least one transmission cable and provides the adjusted receive signal to the user communication system, and in the transmit mode the amplitude adjustment circuit adjusts the amplitude of the transmit signal and provides the adjusted transmit signal to the antenna system via the at least one transmission cable.

3. The system of claim 1, wherein the transmission line measurement circuit comprises: a calibration signal generator configured to provide a calibration signal from the antenna control circuit to the antenna system on the at least one transmission line cable, the calibration signal being retransmitted as a return signal from the antenna system back to the antenna control circuit; and a a signal monitor configured to detect a characteristic of the return signal and determine the signal loss based on the characteristic of the return signal.

4. The system of claim 3, wherein the calibration signal generator provides the calibration signal in response to one of an amplitude change of a DC control voltage provided on the at least one transmission line cable or a tone signal.

5. The system of claim 3, wherein the signal monitor is configured to measure a first power associated with the calibration signal provided on the at least one transmission line cable and measure a second power associated with the return signal on the at least one transmission line cable to determine the signal loss as a ratio of the first power to the second power.

6. The system of claim 5, wherein the at least one transmission line cable includes a first transmission line cable and a second transmission line cable, wherein the signal monitor is configured to measure the first power associated with the calibration signal provided on the first transmission line cable and measure the second power associated with the return signal received on the second transmission line cable.

7. The system of claim 1, wherein the antenna system includes extraction circuitry configured to receive DC power from the antenna control circuitry via the at least one transmission line cable.

8. The system of claim 1, wherein the controller is further configured to switch from the transmit mode to the receive mode in response to the monitored signal power being below the predetermined threshold.

9. The system of claim 1, wherein: the transmit signal is a first transmit signal and the receive signal is a first receive signal; the antenna system includes a first antenna array that transmits the first transmit signal and the first receive signal, and further includes a second antenna array that transmits a second transmit signal and a second receive signal; the signal path of the amplitude adjustment circuitry is a first signal path; the amplitude adjustment circuitry is a first amplitude adjustment circuitry; the receive amplitude adjustment is a first receive amplitude adjustment; the transmit amplitude adjustment is a first transmit amplitude adjustment; the receive mode is a first receive mode; the transmit mode is a first transmit mode; and in a second receive mode, a second amplitude adjustment circuitry applies a second receive amplitude adjustment to the second receive signal along a second signal path, and in a second transmit mode, a second amplitude adjustment circuitry applies a second transmit amplitude adjustment to the second transmit signal along the second signal path.

10. The system of claim 9, wherein: the at least one transmission line cable includes a first transmission line cable and a second transmission line cable; and the antenna control circuitry uses the antenna system to transmit the first receive signal and the first transmit signal via the first transmission line cable, and to transmit the second receive signal and the second transmit signal via the second transmission line cable.

11. The system of claim 1, wherein the antenna control circuit further comprises a memory to store the determined signal loss.

12. The system of claim 1, wherein the transmit detection circuit comprises a directional coupler and a power detector to monitor the signal power of the transmit signal.

13. A method for communicating at least one of a transmit signal in a transmit mode and a receive signal in a receive mode via a time division duplex (TDD) antenna communication system comprising an antenna system, the antenna system configured to communicate the transmit signal and the receive signal to and from the user communication system without active control communications between the antenna system and the user communication system, wherein the antenna system is used to facilitate bi-directional time division duplex communication between transmit and receive signals without requiring communications or signaling from the user communication system; the method comprising: providing a calibration signal from an antenna control circuit to the antenna system on at least one transmission line cable; receiving a return signal corresponding to the calibration signal retransmitted from the antenna system back to the antenna control circuit on the at least one transmission line cable; determining a signal loss between the antenna system and the antenna control circuit over the at least one transmission line cable based on the return signal; monitoring, by a transmit detection circuit, a signal power of the transmit signal obtained from a user communication system along a signal path within the antenna control circuit and generating a transmit mode signal based on the signal power; receiving, by a controller connected to the transmit detection circuit, the transmit mode signal from the transmit detection circuit to generate a mode signal and providing the mode signal to an amplitude adjustment circuit; switching the amplitude adjustment circuit from the receive mode to the transmit mode in response to the mode signal indicating that the monitored signal power exceeds a predetermined threshold; generating, by the controller, a control signal and providing the control signal to the amplitude adjustment circuit; and applying, by the amplitude adjustment circuit and in response to the control signal, a receive amplitude adjustment to the receive signal in the receive mode along the signal path based on the determined signal loss and applying, by the amplitude adjustment circuit, a transmit amplitude adjustment to the transmit signal in the transmit mode along the signal path based on the determined signal loss.

14. The method of claim 13, wherein determining a signal loss comprises: detecting a characteristic of the return signal; and determining the signal loss based on the characteristic of the return signal.

15. The method of claim 13, wherein providing the calibration signal comprises providing the calibration signal in response to a calibration command.

16. The method of claim 13, wherein determining a signal loss comprises: measuring a first power associated with the calibration signal provided on the at least one transmission line cable; and determining the signal loss based on the measured first power. measuring a second power associated with the return signal on the at least one transmission line cable to determine the signal loss as a ratio of the first power and the second power.

17. The method of claim 16, wherein the at least one transmission line cable includes a first transmission line cable and a second transmission line cable, wherein measuring the first power includes measuring the first power associated with the calibration signal provided on the first transmission line cable, and measuring the second power includes measuring the second power associated with the return signal received on the second transmission line cable.

18. The method of claim 13, further comprising switching from the transmit mode to the receive mode in response to the monitored signal power being below the predetermined threshold.

19. The method of claim 13, wherein: the transmit signal is a first transmit signal and the receive signal is a first receive signal; the antenna system includes a first antenna array that transmits the first transmit signal and the first receive signal, and further includes a second antenna array that transmits a second transmit signal and a second receive signal; the amplitude of the receive signal includes a first amplitude of the first receive signal; the receive mode includes a first receive mode; the determined signal loss includes a first determined signal loss; the signal power includes a first signal power; the amplitude adjustment circuit includes a first amplitude adjustment circuit; and the transmit mode includes a first transmit mode, the method further comprises: adjusting a second amplitude of a second receive signal received via the at least one transmission line cable in a second receive mode based on a second determined signal loss; monitoring a second signal power of a second transmit signal obtained from the user communication system; switching a second amplitude adjustment circuit from the second receive mode to a second transmit mode in response to the monitored second signal power exceeding the predetermined threshold; and adjusting a second amplitude of the second transmit signal in the second transmit mode based on the determined signal loss.

20. The method of claim 19, wherein the at least one transmission line cable includes: a first transmission line cable on which the first receive signal and the first transmit signal are transmitted between the antenna system and the antenna control circuit; and a second transmission line cable on which the second receive signal and the second transmit signal are transmitted between the antenna control circuit and the antenna system.

21. The method of claim 13, further comprising storing the determined signal loss in a memory.

22. The method of claim 13, wherein monitoring the signal power of the transmit signal includes monitoring the signal power of the transmit signal via a directional coupler and a power detector. ​ ​

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