Patent Description:
As vehicles incorporate more wireless communication technologies, the requirements for wireless connectivity in vehicles increases. For example, many vehicles are configured for vehicle-to-everything (V2X) applications, including LTE legacy, <NUM>, and WiFi, etc. These technologies generally require antennas and radio frequency front ends ("RFFE") to be integrated on the surface of a vehicle, such as on the roof, the hood, the trunk, and/or on the side mirrors, etc. These locations can be particularly hostile environments for radio frequency ("RF") electronics and especially to the low-efficiency RF power-amplifiers that require bulky or complex cooling solutions. Moreover, shark-fin and similar assemblies may suffer from a solar-oven effect, which may raise their internal ambient temperature to very high levels under hot and/or sunny conditions. These increased temperatures may significantly degrade performance of the semiconductors within the wireless connectivity equipment.

In addition, the design of the antenna/RFFE must conform with industrial car design practices and/or goals. For example, it is known to separate the antenna front end from the RFFE, such that the RFFE may be housed in a part of the vehicle that is less susceptible to the above solar-oven effect; however, such solutions generally involve multiple cables to connect the RFFE to the various antennas, thereby substantially increasing weight and cost.

Microwave and mmW communications systems for complex platform integration may furthermore require multiple, distributed, interconnecting radio circuits. For example, this may be common in a vehicle, in which radio circuitry must be located in a variety of places within a vehicle and still maintain functional interconnections. Various methods have been attempted for connecting these distributed systems. For example, it is known to use coaxial cables for connection of distributed RF circuity. Similarly, a variety of waveguides are known for maintaining such distributed RF systems, such as in automobiles. Modern automobiles with advanced RF-systems may be particularly cable-dependent, with complex cable distributions which add significant cost (materials and installation) and weight. These cable bundles may be required to carry any combination of DC-power cables, low-frequency cables, and RF cables.

In certain installations, it may be required to interconnect multiple antennas to distributed TX/RX circuitry, which may be located significant distances from the antennas. For example, it is known in various vehicles to connect antennas to circuitry that is ~<NUM>-<NUM> away. Thus, it becomes necessary to utilize a low-loss waveguide. RF/microwave/mmW interconnections running from antennas to radio circuitry must to conform to the vehicle dimensions / surfaces to minimize footprint or the space occupied by them. Moreover, interconnecting distributed radio elements around the vehicle may also require running long DC or low-speed data lines. This increases costs because the interconnecting lines are manufactured and assembled separately.

Known methods of achieving these aims may have various disadvantages. For examples, coaxial cables may have significant insertion losses at RF/microwave and mmWaves. Conventional waveguides and gap waveguides are generally inflexible and poorly suited to the curves and/or bends of vehicles. Corrugated waveguides increase waveguide height to accommodate corrugation, which adds significant bulk, and thus may be disadvantageous. Twisted-pair transmission lines often have high manufacturing cost, low frequency operation, and poor electromagnetic compatibility. DC, low-frequency and RF/mmW Cable Distribution are known to resent challenges with radio frequency interference, electromagnetic interference, and other coexistence issues.

<CIT> describes an electronic device that may include an antenna, a transceiver, and a low noise amplifier module that amplifies receive signals from the antenna to the transceiver circuitry in a first configuration and passes transmit signals from the transceiver to the antenna in a second configuration. The low noise amplifier module may include a first switching circuit coupled to the antenna, a second switching circuit coupled to the transceiver, at least one low noise amplifier coupled between the first and second switching circuits, and a transmit bypass path coupled between the first and second switching circuits. The operations may be performed by generating and providing control signals using baseband circuitry or other control circuitry in an electronic device.

<CIT> describes a monitoring and troubleshooting system to determine whether or not an antenna that is used for receiving wireless weak signals is operational.

The object to be solved is to effectively operate a connection between a radio frequency front end and an antenna front end in an efficient manner. The object is achieved by the present invention in the aspects of a circuitry and a method having the features of the independent claims. Additional features for advantageous embodiments are provided in the dependent claims.

The following detailed description refers to the accompanying drawings that show, by way of illustration, specific details and aspects in which the disclosure may be practiced. One or more aspects are described in sufficient detail to enable those skilled in the art to practice the disclosure. Other aspects may be utilized and structural, logical, and/or electrical changes may be made without departing from the scope of the disclosure. The various aspects of the disclosure are not necessarily mutually exclusive, as some aspects can be combined with one or more other aspects to form new aspects. Various aspects are described in connection with methods and various aspects are described in connection with devices. However, it may be understood that aspects described in connection with methods may similarly apply to the devices, and vice versa.

The term "exemplary" may be used herein to mean "serving as an example, instance, or illustration". Any aspect or design described herein as "exemplary" is not necessarily to be construed as preferred or advantageous over other aspects or designs.

The terms "at least one" and "one or more" may be understood to include a numerical quantity greater than or equal to one (e.g., one, two, three, four, [. The term "a plurality" may be understood to include a numerical quantity greater than or equal to two (e.g., two, three, four, five, [.

The phrase "at least one of" with regard to a group of elements may be used herein to mean at least one element from the group consisting of the elements. For example, the phrase "at least one of" with regard to a group of elements may be used herein to mean a selection of: one of the listed elements, a plurality of one of the listed elements, a plurality of individual listed elements, or a plurality of a multiple of listed elements.

The words "plural" and "multiple" in the description and in the claims expressly refer to a quantity greater than one. Accordingly, any phrases explicitly invoking the aforementioned words (e.g., "a plurality of (objects)", "multiple (objects)") referring to a quantity of objects expressly refers more than one of the said objects. The terms "group (of)", "set (of)", "collection (of)", "series (of)", "sequence (of)", "grouping (of)", etc., and the like in the description and in the claims, if any, refer to a quantity equal to or greater than one, i.e. one or more.

The term "data" as used herein may be understood to include information in any suitable analog or digital form, e.g., provided as a file, a portion of a file, a set of files, a signal or stream, a portion of a signal or stream, a set of signals or streams, and the like. Further, the term "data" may also be used to mean a reference to information, e.g., in form of a pointer. The term "data", however, is not limited to the aforementioned examples and may take various forms and represent any information as understood in the art. Any type of information, as described herein, may be handled for example via a one or more processors in a suitable way, e.g. as data.

The terms "processor" or "controller" as, for example, used herein may be understood as any kind of entity that allows handling data. The data may be handled according to one or more specific functions executed by the processor or controller. Further, a processor or controller as used herein may be understood as any kind of circuit, e.g., any kind of analog or digital circuit. A processor or a controller may thus be or include an analog circuit, digital circuit, mixed-signal circuit, logic circuit, processor, microprocessor, Central Processing Unit (CPU), Graphics Processing Unit (GPU), Digital Signal Processor (DSP), Field Programmable Gate Array (FPGA), integrated circuit, Application Specific Integrated Circuit (ASIC), etc., or any combination thereof. Any other kind of implementation of the respective functions, which will be described below in further detail, may also be understood as a processor, controller, or logic circuit. It is understood that any two (or more) of the processors, controllers, or logic circuits detailed herein may be realized as a single entity with equivalent functionality or the like, and conversely that any single processor, controller, or logic circuit detailed herein may be realized as two (or more) separate entities with equivalent functionality or the like.

The term "memory" detailed herein may be understood to include any suitable type of memory or memory device, e.g., a hard disk drive (HDD), a solid-state drive (SSD), a flash memory, etc..

Differences between software and hardware implemented data handling may blur. A processor, controller, and/or circuit detailed herein may be implemented in software, hardware and/or as hybrid implementation including software and hardware.

The term "system" (e.g., a sensor system, a control system, a computing system, etc.) detailed herein may be understood as a set of interacting elements, wherein the elements can be, by way of example and not of limitation, one or more mechanical components, one or more electrical components, one or more instructions (e.g., encoded in storage media), and/or one or more processors, and the like.

The following detailed description refers to the accompanying drawings that show, by way of illustration, specific details and aspects of this disclosure in which the invention may be practiced. Other aspects may be utilized and structural, logical, and electrical changes may be made without departing from the scope of the invention. The various aspects of this disclosure are not necessarily mutually exclusive, as some aspects of this disclosure can be combined with one or more other aspects of this disclosure to form new aspects.

To the extent that the embodiments described herein relate specifically to use in a vehicle, or are described only with respect to vehicle use, the connection to a vehicle is intended to be illustrative and should not be understood to be limiting. The principles and methods described herein, such as the single-cable connection of a RFFE and an antenna front end, or the connection of waveguides, may have broad application outside of the realm of vehicles. For example, the principles and methods described with respect to single-cable connection of an RFFE and an antenna front end may be applied in a variety of situations, such as where it is desired to separate the RFFE and the antenna front end, due to heat, aesthetics, or for any other reason, or in situations in which it is desired to minimize cable usage. Furthermore, waveguides are frequency discussed in this disclosure as being used in a vehicle. The vehicle as a site of use of the waveguides is employed herein for demonstrative purposes only. The principles, methods, and devices disclosed herein with respect to a waveguide may be applied in a variety of other situations, and therefore the inclusion of a vehicle in the description should be considered to be limiting.

It is known to separate the RFFE and the AFE such that the antenna front end includes a minimal possible circuit close to antenna such as the LNA and switches, which allowed the electronics to be small and minimizes the required heat load to be able to meet the aesthetic requirements with a small heat sink. However, conventional methods of connecting the antenna front end and the RFFE typically require four cables (power, control and Rx and Tx coaxial cables) per antenna, wherein two of the four cables must generally be coaxial cables. Thus, in a vehicle with four antennas in the roof, at least sixteen cables would be required to connect the four antennas to the RFFE. Such cables account for a significant portion of the weight and expense of modern vehicles, and it is therefore desirable to reduce the number of cables for improved weight (fuel economy etc.) and cost.

In light of the foregoing, it is desired to meet high transmit power requirements with aesthetic antenna design (including antenna front end), provide reliable cooling without the need for a bulky non-aesthetic solution, and to minimize increase in materials costs and the weight of a vehicle.

Herein is disclosed a novel cable and assembly design that reduces the number of cables significantly especially in a car environment which requires a long and complex cable/harness system. Limiting the cables between the antenna front end and the RFFE to one cable may have multiple advantages. First, it may minimize the added weight to the vehicle. Second, it may significantly reduce cost (the cost of cables is significant in vehicle manufacture). Third, it may allow small form-factor, low-heat loads and aesthetic antenna front end design, since no power amplifier ("PA") is required in AFE, and the AFE circuitry is minimized. Reducing the number of cables from four to one can be achieved via a controlled time domain duplexing (TDD) system. Moreover, this TDD system may be ideal for Digital Pre-Distortion (DPD) to further enhance PA linearity and meet strict spectral emission mask requirements (<NUM>. 11p), since this system permits the PA to be located close to the RFIC. Furthermore, PA and RFIC cooling is simplified, since they can both be located in a less hostile environment compared to a roof-top or shark-fin.

Vehicular communications may require multiple antennas to increase reliability and or support different technologies such as C-V2X, WiFi, GNSS or LTE/<NUM>. <FIG> depicts a known technique for separating the RFFE from the antenna <NUM>. As shown in <FIG>, and at least due to the common omnidirectional coverage requirement, it is often preferred to place the antennas on the roof-top or another outer surface of the car. As shown in this figure, it is known to place the antenna <NUM> on the rooftop <NUM>, but this method separates from the antenna <NUM> the RFFE <NUM>. In this case, the RFFE <NUM> may include a low noise amplifier ("LNA") <NUM>, the power amplifier <NUM>, an integrated circuit <NUM>, and/or a baseband processor <NUM>. It is known to store the RFFE <NUM> in the shark-fin of the vehicle. This location, however, is very hostile for the electronics, as the rooftop can easily reach temperatures of greater than +<NUM>, and thus any electronics in a shark-fin or similar assembly may experience very high ambient temperatures even before they are under an electrical load. Moreover, the solar-oven effect raises the temperature inside the shark-fin to even higher temperatures, as there generally is no air circulation within the shark-fin due to the waterproof design requirement. Cooling the RF power amplifier generally requires a bulky cooling solution which is not easily designed to be aesthetic and adds weight to the vehicle. Moreover, this method experiences degraded performance due to the distance between the antenna and the LNA.

<FIG> depicts a known placement of the antenna <NUM> with close proximity to the LNA to compensate for the poor noise figure of <FIG> In this example, the rooftop <NUM> contains at least one antenna <NUM>, which is connected to, and generally in close proximity to the LNA / LNA switch <NUM> and the power amplifier <NUM>. The RFFE <NUM> is placed externally to, or in another part of the vehicle with respect to, the AFE <NUM>. The RFFE <NUM> may include an integrated circuit <NUM> and/or a baseband processor <NUM>. To correct the degraded performance due to the distance between the antenna and the LNA, it may be preferred to have only the LNA and switches (i.e. the AFE <NUM>) close to the antenna <NUM> to minimize the noise figure. In this configuration, four cables must generally be run between the RFFE and the AFE. The requirement for four cables represents a substantial increase in cost and weight, which may be undesirable or unacceptable.

<FIG> depicts a known placement <NUM> with the PA, integrated circuit, and baseband processor located separated from the antennas and LNAs. It may be particularly beneficial to have the PA close to the RFIC, as this permits easily coupling of the PA output for digital pre-distortion (DPD) purposes, which is an energy-efficient way to meet strict spectral mask requirements. This may be particularly meaningful for car-to-car communication applications, which operate at the frequency of <NUM>, near WiFi frequencies (for example the strict IEEE <NUM>. 11p spectral mask). In this example, the rooftop <NUM> is configured with a plurality of antennas 304a-304d (i.e., such as in a MIMO installation), wherein each antenna is connected to a corresponding AFE 308a-308d, each including an LNA and a switch. Separate from the AFE, and generally located in another portion of the vehicle, the RFFE <NUM> may be placed in a location that is thermally advantageous for its semiconductor circuitry. In this case, the RFFE <NUM> may include a PA for each of the antennas 310a-310d, integrated circuit <NUM>, and a baseband processor <NUM>. As stated above, the conventional connection between the RFFE <NUM> and the AFE <NUM> includes two electrical wires and two coaxial cables per antenna. In this simple, four-antenna MIMO installation, sixteen cables / wires are necessary. This represents a significant increase in cost and weight, and may be undesirable or unacceptable.

<FIG> depicts a DPD system <NUM> that is operated with close physical relationship between the PA and the integrated circuit. The PA output may be coupled to and received by a digital baseband, where the algorithm finds correct predistortion coefficients which maximize PA linearity. In this example, the processor <NUM> executes a DPD algorithm <NUM>. The processor <NUM> is connected to an integrated circuit <NUM> which is connected to the power amplifier <NUM>. In installations in which the PA is located far from RFIC, an additional cable is required to provide a feedback signal for the DPD algorithm, which thus increases both the weight and materials costs, which may be undesirable or unacceptable.

The conventional solution for connecting the AFE to the RFFE in a time domain duplexing ("TDD") system is to have one receiving ("Rx") coaxial cable, one transmitting ("Tx") coaxial cable, one power cable, and one control cable. The benefit of this solution is that it has the lowest insertion loss for Tx and Rx and fastest control rate due to its dedicated control cable. This conventional solution is depicted in <FIG>, which shows an RFFE <NUM>, including a baseband processor <NUM>, and integrated circuit <NUM>, a power amplifier <NUM>, and an LNA <NUM>. The RFFE <NUM> is connected to an AFE <NUM>, which includes an LNA <NUM>, a control circuit <NUM>, the power circuit <NUM>, a switch <NUM>, and an antenna <NUM>. The electrical connections between the RFFE <NUM> and the AFE <NUM> are created by four cables, the control cable <NUM>, the power cable <NUM>, the first coaxial cable <NUM>, and the second coaxial cable <NUM>.

As can be seen from <FIG>, this method requires two expensive coaxial cables and two additional cables (four in total) for each AFE, which quickly increases the materials costs, increases the form-factor of boards due to multiple connectors, and increases the weight of the system, all of which are non-preferred by car manufacturers. This may be particularly true in a MIMO and/or diversity antenna system.

Rather than utilizing four cables for this connection, it is possible to effectively operate the connection between the RFFE and the AFE using only one coaxial cable. This single coaxial cable concurrently or simultaneously carries DC-power, the RF-signal, and the control signal to toggle between Tx and Rx.

<FIG> depicts a connection of a RFFE and an AFE using a single-cable, according to an aspect of the disclosure. In this example, the RFFE <NUM> may include an LNA <NUM>, a PA <NUM>, a power source <NUM>, a current sensing circuit <NUM>, a comparator <NUM>, and integrated circuit (not pictured), and/or a baseband processor (not pictured). The AFE <NUM> may include a power detector <NUM>, a comparator <NUM>, one or more switches 618a-618b, an LNA <NUM>, and/or and antenna <NUM>. The RFFE <NUM> is connected to the AFE <NUM> via a coaxial cable <NUM>.

Both the RFFE <NUM> and the AFE <NUM> may be configured to be in Rx mode (e.g., a first operational mode) as a default. That is, the LNA <NUM> may be active and the switches (connecting <NUM> and <NUM>, as well as switches 618a and 618b) may be connected to the receiver by pull-ups or pull-downs to maintain default in the first operational mode. When transmission is required, the RFFE <NUM> and AFE <NUM> are switched from Rx mode (first operational mode) to Tx mode (second operational mode). This switching of operational modes may occur by changing the RFFE switch (between <NUM> and <NUM>) to Tx (and thereby disabling the RFFE LNA <NUM> and enabling the RFFE PA <NUM>). The RFIC may transmit a wake-up signal or operational mode switching signal. The wake-up signal or operational mode switching signal may be any signal that can trigger the following steps. According to one aspect of the disclosure, the wake-up signal or operational mode switching signal may be a carrier signal. The wake-up signal or operational mode switching signal may be constantly or generally constantly transmitted to during periods in which the RFFE <NUM> and AFE <NUM> should be in the second operational mode. This wake-up signal or operational mode switching signal may be detected by an RF-power detector <NUM> within the AFE. An output of the RF-power detector <NUM> may be monitored by a comparator <NUM>, which may toggle switches and disable the AFE LNA <NUM> when the RF-power is outside of a predetermined power range. It is expressly noted that there may be a variety of techniques available to cause an output of the RF-power detector <NUM> to disable the AFE LNA620. The use of a comparator is shown here; however, this is not meant to exclude any other technique that may be utilized by a person skilled in the art. For example, logic gates and/or microprocessors could be utilized to the same effect.

Once the RFFE <NUM> has switched to the PA <NUM> and the AFE <NUM> has disabled the LNA <NUM>, both the AFE <NUM> and the RFFE <NUM> are fully ready for high power Tx; however, the baseband (BB) processor (not pictured), in or connected to the RFFE <NUM>, does not know whether AFE is ready. Thus, it is desired to have a procedure for the RFFE <NUM> to detect whether the AFE <NUM> is prepared for the second operational mode. For this, it is of particular relevance that the power consumption of the AFE consists mainly of LNA power consumption. As such, disconnecting the AFE LNA <NUM> is expected to significantly reduce the current draw of the AFE <NUM>. Accordingly, the status of the AFE (and whether it has been successfully prepared for the second operational mode) can be determined by monitoring the AFE's current draw within the RFFE <NUM>. This is achieved by means of a current sensor <NUM>, which measures the current from the AFE <NUM>. A person skilled in the art will appreciate that the current sensor <NUM> may be connected to the AFE <NUM> via a RF-choke, which would be expected to predominantly block the RF output of the AFE <NUM>, such that the current sensor <NUM> measures predominantly the AFE's current demands. Again, a comparator <NUM> may receive the output of the current sensor <NUM> and to toggle an AFE <NUM> status bit to the BB-processor, thus indicating to the BB-processor that the AFE <NUM> has entered the second operational mode and that transmission is now possible. As with the previous use of a comparator, it is expressly contemplated that a variety of implementations may be used to compensate for or replace the comparator <NUM>, such as by using one or more logic gates and/or one or more processors. The reference to a comparator <NUM> herein is not intended to be limiting.

Whenever transmission is completed, the AFE can be switched back to receive mode and the LNA can be enabled by simply disabling RF-signal (wake-up signal or operational mode switching signal). In so doing, the reverse procedure as that which is described above takes place. Specifically, the power detector <NUM> may detect that the wake-up signal/operational mode switching signal has been turned off, and the comparator <NUM> may receive the output of the power detector <NUM> and may enable the LNA <NUM> by causing the switches 618a and 618b to flip. With the LNA <NUM> enabled, the AFE <NUM> may draw additional current, which is then sensed by the current sensor <NUM>, which triggers the comparator <NUM> to inform BB-processor that the current draw is increased as the LNA is enabled (i.e., the device is now ready for reception).

According to one aspect of the disclosure, it may be desirable that the Rx-to-Tx toggling (i.e., switching from a first operational mode to a second operational mode, or vice versa) occurs rapidly. In certain implementations, it may be desirable for this switching to occur in very rapid speeds, such as in less than <NUM>.

Because rapid switching times may be required, it was desired to test the potential switching times of this proposed arrangement. In order to perform this test, a SPICE simulation circuit was built with LTSpice. Active circuits were modeled using Analog Devices/LTC components and the LNA was a voltage controlled switch (used to model its current consumption). <FIG> depicts the simulated waveforms of this test.

Turning to <FIG>, the transition from a first operational mode to a second operational mode begins at ("<NUM>"), with a <NUM> RFFE switching delay. At ("<NUM>"), the RF-power detector begins to output a voltage corresponding to the input power of the AFE. The notch at <NUM> is due to reflections that occur when the switches change their state. ("<NUM>") depicts the point at which the AFE comparator disables the LNA and switches to the second operational state. ("<NUM>") depicts the measured current beginning to decrease at the RFFE as a result of the LNA having been disconnected. ("<NUM>") depicts the AFE current as measured at the RFFE decreasing such that it is outside of a predetermined range, and thus the comparator toggles to inform the baseband processor that the transition to the second operational mode is complete.

The longest delay may be caused by the current measurement, nevertheless, the system can toggle in less than <NUM>. Alternatively, the system could be characterized by chosen cable lengths and omit this phase cutting the transition time to approximately <NUM>. In general, for fixed systems, it can be measured how long it takes between the initial control signal at the RFFE and the time at which the AFE becomes ready. The AFE may be considered ready when its current begins to decrease. In this case, and since the period of time before AFE readiness is expected to be constant, a timer corresponding to this period of time may be set. At the conclusion of the time, the BB-processor could enable high-power transmission. By utilizing the timer, it may be possible to omit the current sensor in the RFFE. Referring to <FIG>, the comparator threshold could be set to, for example, <NUM>. 5V; however, this may be too close to the steady state current consumption. With the use of the fixed timer described above, the slow current measuring phase may be omitted, and the TX may be enabled more closely to the point where the current is beginning to decrease (i.e., when the AFE is ready to transmit).

In that case, the switching time would be mostly due to the <NUM> toggling time of the RF-switches. Power detectors and comparators operate with delays of tens of nanoseconds, causing minimal delays in the <NUM> budget. While this simulation was fully analog, alternatively, the comparator could be a low power microcontroller with built-in comparator if additional functionality was required at the AFE such as minimum time spent at Tx or Rx mode.

Additionally, the impact on the RF-performance was analyzed. For an RF-optimized case, there would normally be dedicated cables for Tx and Rx to minimize insertion losses, such as depicted in <FIG>. Comparing the electrical connections (e.g., the <NUM> cables) to those of <FIG>, the single-cable systems may be implemented using two additional switches and a coupler in the signal path.

This configuration may have a minimal impact on the noise figure, since the LNA may be very close to the antenna in the configurations depicted in both <FIG>. A single-cable system appears to have a larger effect on PA requirements, as the two additional switches and a coupler tend to cause additional insertion loss which must be compensated for.

Additionally, and according to another aspect of the disclosure, it may be desirable that the required coupler has a low coupling such as <NUM> dB or <NUM> dB and thus would have a very low theoretical insertion loss. Couplers of these coupling values mostly have losses due to practical implementation and could be assumed to be less than <NUM> dB. The added insertion loss due to single cable solution compared to multiple cables is thus <NUM> dB up to <NUM> or even less, depending mainly on the switch performance and operating frequency. While not negligible, it can be compensated for by increasing PA-output power - especially considering that the PA is now located in a place where cooling can be arranged conveniently.

According to another aspect of the disclosure, and with respect to vehicle installation, it may be desirable to have the RFFE, RFIC, and baseband processor inside an enclosure, for example, the headliner, the trunk or the dashboard. This may minimize the length and insertion loss of the required coaxial cables to the multiple AFEs. Further, using the single-cable connection described herein, only one cable per antenna is required, which limits the cable-burden of separating the RFFE from the AFE. Given the challenges of temperature regulation for the PA, it is noted that a module located inside headliner and/or dashboard may be able to leverage cabin air conditioning for cooling. This architecture and single-cable solution may provide advantages in terms of system performance and efficiency by reducing the number of cables, relaxing thermal requirements, reducing materials costs, etc. The impact may be magnified in MIMO/diversity antenna systems, in which the reduction from four cables to one cable per antenna is realized over a plurality of antennas.

<FIG> depicts a single-cable installation with multiple antennas <NUM>, according to an aspect of the disclosure. In this figure, four antennas (such as in a MIMO installation) are installed within the rooftop <NUM> of the vehicle. These are depicted herein as antennas 804a-804d, which are connected to AFE 808a-808d, respectively, each of which are connected to the RFFE <NUM>. With the RFFE <NUM>, are four PA 810a-810d, each of which are connected to one of the antennas. A single RF-cable connects the RFFE <NUM> to each of the AFEs 808a-808d.

<FIG> depicts a method of duplexing including sending an operational mode switching signal from a radio frequency front end to an antenna front end <NUM>; detecting in the antenna front end the operational mode switching signal <NUM>; and disconnecting a low noise amplifier from an electrically conductive connection between an antenna of the antenna front end and the radio frequency front end, based on the detected operational mode switching signal <NUM>.

As described herein, both the RFFE and the AFE may be configured to operate according to either of a first operational mode or a second operational mode. The first operational mode may be understood for the purposes herein as a receive mode, and the second operational mode may be understood as a transmission mode. The RFFE and the AFE may be configured to default to either the first operational mode or the second operational mode. In the examples disclosed herein, the RFFE and the AFE are defaulted to the first operational mode (i.e. reception mode). This default can be achieved by means of a pullup or pulldown circuit.

Although the examples disclosed herein specifically relate to a default of the first operational mode, the RFFE and the AFE may alternatively be arranged to default to the second operational mode. That is, the RFFE and the AFE may be configured with a pullup or pulldown circuit such that they default in transmission mode. According to this configuration, the operational switching signal of the processor in the RFFE would cause the power detector of the AFE and its connected comparator to engage the LNA of the AFE. The increased current draw triggered by the engagement of the LNA would be detected by the current sensing circuit in the RFFE which, in connection with the comparator, would inform the processor that the first operational mode has been entered.

The RFFE and the AFE may be configured such that the operational mode switching signal of the RFFE causes the operational mode to change from the first operational mode to the second operational mode, and further that pausing the operational mode switching signal of the RFFE causes the RFFE and the AFE to switch from the second operational mode to the first operational mode. That is, pausing the operational mode switching signal causes the RFFE and the AFE to revert to their default operational mode state.

To the extent that any specific parameters have been referenced herein with respect to any of the components of the switching circuits (e.g. LNAs, PAs, current sensing circuits, power detectors, comparators, switches, or the like), it is expressly anticipated that the specifications of these components may be selected and/or adapted to a particular installation. That is, many of the components must be configured relative to the other components and the needs of the installation. For example, the current sensing circuit/current sensor must be selected to sensor current that corresponds with the current usage of the LNA in the AFE. Similarly, the power detector of the AFE must be selected to correspond to the operational mode switching signal of the RFFE, and vice versa.

In the methods and procedures disclosed herein, the LNA of the AFE may be engaged or disengaged from the system by means of two switches (depicted in <FIG> as 618a and 618b). Although such switches may be a convenient means to achieve the same, it is contemplated that other methods of electrically conductively connecting the LNA within the conductive path between the antenna and the RFFE may be employed. The person skilled in the art will appreciate a variety of circuitry or implementation techniques for the same, and the use of two switches is not intended to be limiting in this matter.

According to an aspect of the disclosure, the RFFE may include a switch to selectively connect either an LNA or a PA within the RFFE to the electrical path with the antenna. In this case, it is anticipated that the switch will selectively connect to the LNA for reception (the first operational mode) and will selectively connect to the PA for transmission (second operational mode). The switch may be operated by any means which is capable of toggling the switch for the changes between operational modes. According to one aspect of the disclosure, the one or more processors of the RFFE may be utilized to operate the switch for the changing between operational modes along with the generation of the operational mode switching signal.

The methods and principles described herein are designed to be implementable with a single electrically conductive connection between the RFFE and the AFE (i.e., a single coaxial cable). The use of the single coaxial cable permits reduced complexity of implementation, reduced weight, and reduced materials costs.

The RFFE and the AFE may be implemented together or separately. That is, although certain aspects of the RFFE and the AFE must be configured to operate with one another (e.g., the sensor in the AFE must be configured to recognize the operational mode switching signal of the RFFE), the RFFE and the AFE may be manufactured, sold, and/or distributed independently of one another. As such, the RFFE and the AFE may each be considered independent devices.

According to another aspect of the disclosure, a method of antenna duplexing may include sending an operational mode switching signal from a first radiofrequency device to a second radiofrequency device; disconnecting a low noise amplifier from an electrically conductive connection between the first radiofrequency device and an antenna of the second radiofrequency device; detecting a change in current drawn by the second radiofrequency device, as a result of disconnecting the low noise amplifier; and changing from a first operational mode to a second operational mode based on the detected change in current.

The principles and methods described herein may be performed as part of a non-transient computer readable medium, including a plurality of instructions which, when implemented, because one or more processors to perform the methods disclosed herein.

Claim 1:
A circuitry (<NUM>) comprising:
a sensor (<NUM>) configured to detect an electrical signal indicating whether a low-noise amplifier in an antenna front end (<NUM>) is active or not active, wherein the sensor (<NUM>) measures the current drawn from the antenna front end (<NUM>); and
one or more processors, configured to
send an operational mode switching signal to control the antenna front end (<NUM>) to activate or deactivate the low-noise amplifier (<NUM>) in the antenna front end (<NUM>); and
control the antenna front end (<NUM>) to receive or transmit data depending on the indication of the detected electrical signal.