# Patent

## Title
Method and apparatus for managing interference in a communication device

## Abstract

A system that incorporates teachings of the present disclosure may include, for example, a matching network including a tunable reactance circuit configured to be coupled to at least one of a transmitter portion and a receiver portion of a communication device, wherein the tunable reactance circuit is adjustable to a plurality of tuning states, and wherein the determination of a tuning state is based on parameters associated with a detected interference. Additional embodiments are disclosed.

## Background
CROSS-REFERENCE TO RELATED APPLICATIONS
This application claims priority to U.S. Provisional Application Ser. No. 61/326,206 filed on Apr. 20, 2010, the disclosure of which is hereby incorporated by reference in its entirety. This Application is also related to U.S. application Ser. No. 13/090,575 entitled “Method and Apparatus for Managing Interference in a Communication Device” and filed contemporaneously herewith, the disclosure of which is hereby incorporated by reference in its entirety.


FIELD OF THE DISCLOSURE
The present disclosure relates generally to communication device operations, and more specifically to a method and apparatus for managing interference in a communication device.
BACKGROUND
The quality of wireless communications between wireless access points such as Wireless Fidelity (WiFi) or cellular base stations and portable mobile devices such as cell phones and laptop computers can depend on many factors. For example, an antenna's performance in a portable device can be impacted by its operating environment. Multiple use cases can exist for radio handsets, which include such conditions as the placement of the handset's antenna next to a user's head, or in the user's pocket or the covering of an antenna with a hand, which can significantly impair wireless device efficiency. Similarly, the quality of wireless communications can be affected by network topology and location of the mobile device.



BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 depicts an illustrative embodiment of a communication device;
FIG. 2 depicts an illustrative embodiment of a portion of a transceiver of the communication device of FIG. 1;
FIGS. 3-4 depict illustrative embodiments of a tunable matching network of the transceiver of FIG. 2;
FIGS. 5-6 depict illustrative embodiments of a tunable reactive element of the tunable matching network;
FIGS. 7-8 depict illustrative embodiments of portions of communication devices with tunable matching networks;
FIG. 9 depicts a method operating in portions of the communication device of FIGS. 7-8;
FIG. 10 depicts an illustrative embodiment of a portion of communication devices including a power and phase detector;
FIG. 11 depicts an illustrative embodiment of a frequency diagram for the communication device of FIG. 10;
FIGS. 12-16 depict illustrative embodiments of portions of communication devices including power and phase detectors;
FIGS. 17-18 depict illustrative embodiments of exemplary timing diagrams;
FIG. 19 depicts an illustrative embodiment of a portion of a communication device including a power and phase detector;
FIG. 20 depicts an exemplary diagrammatic representation of a machine in the form of a computer system within which a set of instructions, when executed, may cause the machine to perform any one or more of the methodologies disclosed herein.



DETAILED DESCRIPTION
One embodiment of the present disclosure entails a computer-readable storage medium comprising computer instructions to detect an existence of an interferer and determine a tuning state of a matching network having a tunable reactance, where the determination of the tuning state is based on whether the interferer exists and is based on information from at least one of an open-loop or closed-loop feedback configuration.
One embodiment of the present disclosure entails a matching network, comprising: a tunable reactance circuit configured to be coupled to at least one of a transmitter portion and a receiver portion of a communication device, wherein the tunable reactance circuit is adjustable to a plurality of tuning states, and wherein the determination of a tuning state is based on whether an interferer exists and is based on information from at least one of an open-loop or closed-loop feedback configuration of the tunable reactance circuit.
One embodiment of the present disclosure entails a method comprising detecting interference with a communication device based on an existence of an interferer and determining a tuning state of a variable matching network of the communication device based on whether the interferer exists.
One embodiment of the present disclosure entails a communication device comprising a controller to determine a tuning state of a variable matching network that controls one or more operational characteristics of one of a receiver portion and a transmitter portion of the communication device, where the controller is operable to detect an existence of an interferer and determine the tuning state based on whether the interferer exists and based on information from at least one of an open-loop or closed-loop feedback configuration.
One embodiment of the present disclosure entails a method comprising detecting an existence of an interferer that is interfering with a communication device; determining a tuning state of a variable matching network of the communication device based on whether the interferer exists; and adjusting the variable matching network based on the determined tuning state only when the existence of the interferer is not detected.
One embodiment of the present disclosure entails a method comprising detecting interference with a communication device sourced by an interferer; and determining a tuning state of a variable matching network of the communication device based on the detected interference.
One embodiment of the present disclosure entails a method comprising determining parameters of interference with a communication device, the interference being sourced by an interferer; and adjusting a tuning state of a variable matching network of the communication device based on the interference parameters.
One embodiment of the present disclosure entails a matching network comprising a tunable reactance circuit configured to be coupled to at least one of a transmitter portion and a receiver portion of a communication device, wherein the tunable reactance circuit is adjustable to a plurality of tuning states, and wherein the determination of a tuning state is based on parameters associated with a detected interference.
One embodiment of the present disclosure entails a non-transitory computer-readable storage medium comprising computer instructions to determine interference with a communication device; and adjust a tuning state of a variable matching network of the communication device based on parameters associated with the interference.
FIG. 1 depicts an exemplary embodiment of a communication device 100. The communication device 100 can comprise a wireless transceiver 102 (herein having independent transmit and receiver sections, a user interface (UI) 104, a power supply 114, and a controller 106 for managing operations thereof. The wireless transceiver 102 can utilize short-range or long-range wireless access technologies such as Bluetooth, WiFi, Digital Enhanced Cordless Telecommunications (DECT), or cellular communication technologies, just to mention a few. Cellular technologies can include, for example, CDMA-1X, WCDMA, UMTS/HSDPA, GSM/GPRS, TDMA/EDGE, EV/DO, WiMAX, and next generation cellular wireless communication technologies as they arise.
The UI 104 can include a depressible or touch-sensitive keypad 108 with a navigation mechanism such as a roller ball, joystick, mouse, or navigation disk for manipulating operations of the communication device 100. The keypad 108 can be an integral part of a housing assembly of the communication device 100 or an independent device operably coupled thereto by a tethered wireline interface (such as a flex cable) or a wireless interface supporting for example Bluetooth. The keypad 108 can represent a numeric dialing keypad commonly used by phones, and/or a Qwerty keypad with alphanumeric keys. The UI 104 can further include a display 110 such as monochrome or color LCD (Liquid Crystal Display), OLED (Organic Light Emitting Diode) or other suitable display technology for conveying images to an end user of the communication device 100. In an embodiment where the display 110 is a touch-sensitive display, a portion or all of the keypad 108 can be presented by way of the display.
The power supply 114 can utilize common power management technologies (such as replaceable batteries, supply regulation technologies, and charging system technologies) for supplying energy to the components of the communication device 100 to facilitate portable applications. The controller 106 can utilize computing technologies such as a microprocessor and/or digital signal processor (DSP) with associated storage memory such a Flash, ROM, RAM, SRAM, DRAM or other like technologies.
FIG. 2 depicts an illustrative embodiment of a portion of the wireless transceiver 102 of the communication device 100 of FIG. 1. In GSM applications, the transmit and receive portions of the transceiver 102 can include common amplifiers 201, 203 coupled to a tunable matching network 202 and an impedance load 206 by way of a switch 204. The load 206 in the present illustration can be an antenna as shown in FIG. 1 (herein antenna 206). A transmit signal in the form of a radio frequency (RF) signal (TX) can be directed to the amplifier 201 which amplifies the signal and directs the amplified signal to the antenna 206 by way of the tunable matching network 202 when switch 204 is enabled for a transmission session. The receive portion of the transceiver 102 can utilize a pre-amplifier 203 which amplifies signals received from the antenna 206 by way of the tunable matching network 202 when switch 204 is enabled for a receive session. Other configurations of FIG. 2 are possible for other types of cellular access technologies such as CDMA. These undisclosed configurations are contemplated by the present disclosure.
FIGS. 3-4 depict illustrative embodiments of the tunable matching network 202 of the transceiver 102 of FIG. 2. In one embodiment, the tunable matching network 202 can comprise a control circuit 302 and a tunable reactive element 310. The control circuit 302 can comprise a DC-to-DC converter 304, one or more digital to analog converters (DACs) 306 and one or more corresponding buffers 308 to amplify the voltage generated by each DAC. The amplified signal can be fed to one or more tunable reactive components 504, 506 and 508 such as shown in FIG. 5, which depicts a possible circuit configuration for the tunable reactive element 310. In this illustration, the tunable reactive element 310 includes three tunable capacitors 504-508 and an inductor 502 with a fixed inductance. Other circuit configurations are possible, and thereby contemplated by the present disclosure.
The tunable capacitors 504-508 can each utilize technology that enables tunability of the capacitance of said component. One embodiment of the tunable capacitors 504-508 can utilize voltage or current tunable dielectric materials such as a composition of barium strontium titanate (BST). An illustration of a BST composition is the Parascan® Tunable Capacitor. In another embodiment, the tunable reactive element 310 can utilize semiconductor varactors. Other present or next generation methods or material compositions that can support a means for a voltage or current tunable reactive element are contemplated by the present disclosure.
The DC-to-DC converter 304 can receive a power signal such as 3 Volts from the power supply 114 of the communication device 100 in FIG. 1. The DC-to-DC converter 304 can use common technology to amplify this power signal to a higher range (e.g., 30 Volts) such as shown. The controller 106 can supply digital signals to each of the DACs 306 by way of a control bus of “n” or more wires to individually control the capacitance of tunable capacitors 504-508, thereby varying the collective reactance of the tunable matching network 202. The control bus can be implemented with a two-wire common serial communications technology such as a Serial Peripheral Interface (SPI) bus. With an SPI bus, the controller 106 can submit serialized digital signals to configure each DAC in FIG. 3 or the switches of the tunable reactive element 404 of FIG. 4. The control circuit 302 of FIG. 3 can utilize common digital logic to implement the SPI bus and to direct digital signals supplied by the controller 106 to the DACs.
In another embodiment, the tunable matching network 202 can comprise a control circuit 402 in the form of a decoder and a tunable reactive element 404 comprising switchable reactive elements such as shown in FIG. 6. In this embodiment, the controller 106 can supply the control circuit 402 signals via the SPI bus which can be decoded with common Boolean or state machine logic to individually enable or disable the switching elements 602. The switching elements 602 can be implemented with semiconductor switches or micro-machined switches such as utilized in micro-electromechanical systems (MEMS). By independently enabling and disabling the reactive elements (capacitor or inductor) of FIG. 6 with the switching elements 602, the collective reactance of the tunable reactive element 404 can be varied.
The tunability of the tunable matching networks 202, 204 provides the controller 106 a means to optimize performance parameters of the transceiver 102 such as, for example, but not limited to, transmitter power, transmitter efficiency, receiver sensitivity, power consumption of the communication device, a specific absorption rate (SAR) of energy by a human body, frequency band performance parameters, and so on.
To achieve one or more desirable performance characteristics which a designer can define, the communication device 100 can be placed in an anechoic chamber. In this configuration, the designer can perform calibration measurements of performance parameters of the communication device 100 such as Total Radiated Power (TRP), Total Isotropic Sensitivity (TIS) or Radiated Harmonics measurements, receiver efficiency, transmit power efficiency, and power consumption, just to mention a few. For a multi-frequency band communication device 100, the calibration measurements can be performed per band or per sub-band.
Additionally, the calibration measurements can be performed under a number of use cases of the communication device 100 utilizing a phantom body that emulates the composition of a human body. For instance, a communication device 100 having a housing assembly of a flip design, the communication device 100 can be placed next to an ear of the phantom when the flip is open to emulate a typical conversational use case. In a hands-free application such when a user utilizes a Bluetooth headset or when the communication device 100 is in standby mode, the communication device 100 can be placed on a hip of the phantom with the flip closed. Calibration can be performed on other use cases such as antenna up, or down, speakerphone feature “ON” with communication device 100 held with a phantom hand but away from the phantom head. Any number of use cases can be applied to each frequency band and sub-band if desirable.
FIG. 7 depicts an exemplary embodiment of a portion of a communication device 700 (such as device 100 in FIG. 1) having a tunable matching network which can include a number of components such as a directional coupler 710, a detector(s) 720, a High Voltage Application Specific Integrated Circuit (HVASIC) 730 and a tuner 740 (such as an Adaptive Impedance Matching Module (AIMM) tuner)). The tunable matching network can include various other components in addition to or in place of the components shown, including components described above with respect to FIGS. 1-6. The tunable matching network can be coupled to an antenna 780 and a transceiver (or transmitter and/or receiver) for facilitating communication of signals between the communication device and another device or system. In this exemplary embodiment, the communication device 700 is in proximity to an interferer 790 which is interfering with the transmission and reception of signals by the device. Various RF levels are depicted which include a desired range for the transmission level of 0 to +33 dBm. The present disclosure contemplates other RF levels being utilized or encountered. As can be seen, the introduction of the interferer 790 can result in undesired tuning of the device 700.
FIG. 8 depicts an exemplary embodiment of a portion of a communication device 800 (such as device 100 in FIG. 1) having a tunable matching network which can include a number of components such as a coupler 810, a detector(s) 820, a High Voltage Application Specific Integrated Circuit (HVASIC) 830 and a tuner 840 (such as an Adaptive Impedance Matching Module (AIMM) tuner)). The tunable matching network can include various other components in addition to or in place of the components shown, including components described above with respect to FIGS. 1-6. The tunable matching network can be coupled to an antenna 880 and a transceiver (or transmitter and/or receiver) for facilitating communication of signals between the communication device and another device or system. In this exemplary embodiment, the communication device 800 is in proximity to an interferer 890 which is disrupting the tuner control loop, such as the measurement of the antenna VSWR by the device.
Device 800 can include one or more components that allow for the detection of the interferer and an adjustment to the tuning technique based on the interferer detection. For instance, in one exemplary embodiment, the AIMM algorithm can act as a look-up table of tuning states but subject to updating the tuning state when valid measurements can be made. When a measurement is determined to be invalid, then the device can utilize the last known valid tuning state for the particular use case. Other adjustments to the tuning technique can also be utilized. For instance, the tuning can be delayed, such as for a predetermined period of time, until a valid measurement can be made. In another embodiment, if a valid measurement cannot be made within the predetermined time period then the last known valid tuning state for the particular use case can be utilized for tuning.
In one embodiment, isolation between antennas inside the device 800 can be maintained in order to reduce the power of internally generated interferers (such as WiFi and Bluetooth) that are detected at the coupler outputs. The particular level of isolation that is utilized can vary. Examples of multiple antenna systems in communication devices, such as diversity antenna systems, are described in U.S. patent application Ser. No. 13/005,122 filed on Jan. 12, 2011, the disclosure of which is hereby incorporated by reference in its entirety.
In another embodiment, one or more filters 850 can be coupled to the coupler 810. The particular type of filter can vary and can include BT/WiFi elimination filters or BP filters. For example, these filters can be band rejection or band “suckout” circuits. The filter can be a single filter coupled to the reflection output of the coupler 810, but the present disclosure contemplates filters coupled to both outputs of the coupler. In one embodiment, 2.4 GHz elimination filters can be coupled to the output ports of the directional coupler, although other filter ranges can also be utilized.
In one embodiment, a filter 860 (such as a BP filter) can be incorporated into the coupler 810. For instance, since couplers can be built in a multi-layer dielectric structure, filter elements can be incorporated into the structure to deploy the types of band reject or elimination filters desired.
While the previous embodiments have described the use of a directional coupler to detect the VSWR or impedance of the tunable matching network as the source of feedback for the algorithm controlling the tunable network, there are other possible components, techniques and/or means to determine the impedance of the network, or to supply inputs to an algorithm designed to tune the tunable matching network. Known methods for determining impedance matching can also be utilized with the exemplary embodiments described herein. It should be noted that the techniques to avoid and mitigate interfering signals described herein can be applied to other means of determining feedback for the control algorithm.
In another embodiment, a peak detector 870 and an average detector 875 can be coupled to or included within the sensor IC 820 to determine the presence of amplitude modulation such as through comparing forward to reverse output data on constant envelope signals. In one embodiment, the peak and average measurements on the difference between the forward and reverse signals can ignore the transmitter's intentional modulation but detect amplitude modulation from the beat note which is generated by the combination of the desired and interfering signals being present simultaneously.
The exemplary embodiments described herein allow a communication device to mitigate the effects of an interferer that is generating interference that is affecting the communication device. In one embodiment, the device can implement a multi-thread antenna tuning algorithm. For instance, an open loop look-up table can operate to store the nominal tuning state for each band, sub-band, mechanical position, speaker state, etc. (use cases). When transmitting, the algorithm can run to determine if a better tuning state can be found, and can continuously improve it. The tuning state in the look up table can be replaced as the algorithm finds better tuning states for the particular use case in operation. Each Return Loss (RL) or impedance measurement can be checked for validity before the algorithm is allowed to update the tuning state. If an RL measurement is deemed invalid (such as for a single iteration) then the tuner state may not be changed.
Referring to FIG. 9, method 900 can begin with step 902 in which an RF signal is analyzed in order to perform impedance matching using one or more of the components and/or systems described above, including the AIMM tuner 840. In one embodiment, the AIMM algorithm can act as a look-up table of tuning states, which can be updated based on measurements that are determined to be valid. Method 900 can be based on closed-loop and/or open-loop feedback. For instance, the RF signal can be analyzed using closed-loop feedback in combination with open-loop feedback, such as based on stored information that is correlated to a physical state of the device (e.g., in a flipped-open position). The present disclosure also contemplates performing one or more of the steps of method 900 based on only open-loop feedback or based on only closed loop feedback. In step 904, the tuning state can be determined based on the analysis and the feedback described above.
Measurements can then be validated in step 906, such as to detect the existence of an interferer. Validation can be performed in a number of different ways. In one embodiment, a number of return loss phase measurements can be taken over time. A comparison of the maximum to minimum values can be done, and validity can be based on the range being less than a predetermined threshold. For instance, if an interfering signal is present for only some of the measurements, an assumption can be made that the phase of the interfering signal will be different from that of the transmission forward and reflected signals. The timing of the measurements can be long enough such that one burst of a WiFi or other interfering transmission would not be present in all of the measurements, and at least one measurement would fall in between transmission bursts. In another embodiment, the measurements can be processed with respect to the forward and reverse power measurements (amplitude) which are coincident with the phase measurements to determine which are valid and which were made in the presence of an interferer, and ignore only those measurements, while using the valid measurements in the algorithmic computations.
In another embodiment in which the detectors are complete receivers, the forward and reverse demodulated data can be compared to detect interference. For example, complete receivers as detectors in both the forward and received sampled signal paths (such as shown in FIG. 8) can be utilized. These receivers can be tuned specifically to the frequency of the transmitted signal and can thus ignore any interfering signals not on the same frequency or channel. This aspect will eliminate virtually all possible interfering signals in a normal implementation. Also, in this example, the forward and reverse samples should have the same modulation as the desired transmitted signal. If an interferer is present, the receiver may either have the selectivity to ignore the interferer or the received signal may be disrupted and the demodulated data would not match the desired transmitted data. In this latter case, the measurements of forward and reverse power can then be ignored as being invalid.
In one embodiment, multiple fast samples can be taken to detect peaks/nulls that are indicative of interference. For instance, an interfering signal mixing with the desired signals can create a “beat note” in the amplitude. By taking amplitude measurements at very high speeds, method 900 can detect the effective amplitude modulation. If the amplitude modulation exceeds the desired transmitted signal modulation then the measurement can be designated as invalid.
In another embodiment, phase measurements can be analyzed and compared to a threshold for erratic shift (for example applying a 50 ohm exclusion) Phase measurements between non-coherent signals (such as between an interferer and a desired signal) can give random results. Phase measurements between coherent signals (such as the forward and reflected signals) which are close to 50 ohms can also give random results. Phase measurements between coherent signals that are not very close to 50 ohms are relatively stable. If phase signals are erratic (such as change by more than a certain amount between two readings or a standard deviation greater than a certain value or some other method of detecting erratic measurements) then the reflected signal may be an interferer. In one embodiment, the algorithm can be turned off only if both erratic phase is present and the return loss is larger than a certain value (away from 50 ohms).
In another embodiment, sampling can be performed during transmission and when the transmitter is off. For instance, DTX can be used in WCDMA/CDMA to find times when the transmitter is off. In GSM or other Time Division systems, intervals between transmit bursts can be used. A threshold can be compared and applied to a reflected input. If the measured levels during transmission are too close to the levels when the transmitter is off, then the measurement can be deemed invalid. In one embodiment, multiple measurements can be used to detect pulsed interferers.
In one embodiment, an AIMM engagement threshold and Reflection Loss (RL) targets based on detected reflected input (when not transmitting) can be varied. When the transmitter is not active, a measurement of the reflected port can be taken. This measurement can be used to detect an interferer and measure its amplitude. The amplitude of the interferer can be used to set a threshold for the reflected power below which the measurement would be deemed invalid. The interferer level could also be used to adjust the RL target of the algorithm's figure of merit under interferer conditions.
In another embodiment, measurements can be performed both before and after known transmit power level changes and then changes can be compared to predicted change. For instance, the cellular handset controller has knowledge of the power level at which it is transmitting and also the size of any intentional changes to the transmitted power level. To test for the presence of an interferer, the tuning can be kept static and the detected powers/return loss can be measured. If the detected change in power measurements are not within a preset tolerance of the known intentional change, the measurement can be determined to be degraded by an interferer, and measurements can be deemed invalid.
In one embodiment, tuning can be prevented if the RL detected is greater than zero. For instance, if the measured RL is greater than zero (or a predetermined value to allow measurement uncertainty or other variations), then the existence of an interferer has been determined. The predetermined value can further include design knowledge of the tuner and antenna load in a specific application.
If the measurements are determined to be valid then the tuning can be performed as in step 910 to achieve the impedance matching. If on the other hand, the measurements are deemed invalid (such as through the existence of an interferer) then the algorithm can ignore the last inputs and retain the previous tuning state as in step 910. The algorithm can then continue normally and take the next scheduled measurements and again gauge the validity of those measurements. The algorithm can maintain the last known good tuning state until valid measurements allow the algorithm to continue tuning the matching network according to the figure of merit.
Method 900 can apply a number of thresholds in determining the validity of the measurements and detecting the existence of an interferer. For example, the cellular handset controller has knowledge of the power level at which it is transmitting. The AIMM algorithm can be disabled if the known transmit power level is below a predetermined threshold.
Detected levels of interference can be used to set the AIMM on/off control. For example, reflected power measurements that exceed certain thresholds can be invalidated. The thresholds can be dynamic and set as a function of the known transmitted power level, and also as a function of the RL target for the particular channel/use case currently being tuned. As another example, detected level of forward power can be monitored. The cellular handset controller has knowledge of the power level at which it is transmitting. If the forward power detected is in not within a set limit of the desired level, the measurements of both forward and reflected power can be deemed invalid.
In one embodiment, with phase-based tuning algorithms (using impedance targets), predicted RL improvements based on known techniques can be compared to actual measured RL improvements. With RL phase information and a look-up table (LUT) (predetermined open-loop typical tuning state values) or calculations (using known/expected tuner LUT), antenna impedance can be predicted, and correspondingly the tuning state in which to set the tuner can be determined in order to achieve the desired match. After changing the tuning state, if the change in RL/impedance is not within a predetermined threshold of the expected result, then it can be determined that the measurement is being degraded by an interferer, and deemed invalid. The tuner can be restored to its last known good or valid tuning state (such as a default state).
In another embodiment, the tuning range can be limited to increase tuner attenuation at known interferer frequencies.
In typical embodiments there may be additional limitations in the circuitry such as noise thresholds caused by non-coherent signals from within or without a cellular handset or other radio which could affect the validity of detected signals used by an adaptive tuning network. While most of this specification describes the sources of these limitations as interfering signals, this invention is not limited to just the consideration of such signals. The exemplary embodiments can be utilized for tuning of a variable matching network in a communication device based on all types of interference or undesired conditions affecting the communication device. The exemplary embodiments can apply anomaly detection to the tuning algorithm for determining a tuning state.
In one embodiment, a low pass filter can be implemented that eliminates interferers outside of the filter bandwidth. Quadrature mixers can be utilized to avoid cancellation due to in-phase forward and reflection signals. The particular configuration of the components can vary. For instance, a low pass filter and a 90 degree phase shifter can be utilized, and can be incorporated into or otherwise implemented from, the transceiver components. In one embodiment, a VCO can be utilized that is running at twice the frequency and flip-flops can be used for dividing.
In exemplary embodiment 1000 and its corresponding frequency graph 1100, which are shown generally in FIGS. 10 and 11, low pass filters (LPFs) can be utilized to reduce or eliminate all interferers outside the filter bandwidth. The return loss magnitude and/or phase can be obtained by combining fp_I_flt, fp_Q_flt, rp_I_flt, rp_Q_flt in the analog or digital domain. Quadrature mixers can be utilized to avoid cancellation due to RF and LO being in-phase. One or more of the LPFs can be set at values low enough so that AM modulation may be removed.
In one embodiment, the forward signal can be utilized as the LO for the I and Q mixers on the detection IC of embodiment 1000. This eliminates the need for the transceiver IC to provide the LO signal. Another advantage of this method is that the transmit modulation will be present on the LO signal. The modulation envelope can then be eliminated by the mixers. With the modulation eliminated, the baseband lowpass filter can be wider, allowing for a faster measurement than if the LPF had to be set low enough to filter out the modulation. When using the forward signal for the LO, a BPF may be employed to improve performance by attenuating any interferers that may have coupled on to the forward signal.
This exemplary embodiment contemplates use of the same LO as the transmitter or use of a different LO, such as a stand-alone LO (e.g., generated by an IC detector) which can be phase-locked with the transmitter.
In exemplary embodiment 1200 shown generally in FIG. 12, low pass filter(s) (LPFs) can be utilized in combination with power and phase detectors and other control logic for tuning and filtering out interference. In one embodiment, ph1 can be sweeped to maximize node G while ph2 is sweeped to maximize node G2. Other components can be utilized with embodiment 1200, such as an amplitude detector and/or a phase modulator. The RL and phase can be computed.
In another exemplary embodiment 1300 shown generally in FIG. 13, the sweeping and computation described with respect to FIG. 12 can be performed. The LO can be taken from the transmitter, prior to power amplification (PA). For instance, the LO can be obtained from the input to the PA, which may be more accessible to the tuning components. The PA can provide isolation from any interferer and provide a clean LO. The limiter can be utilized to strip away the envelope of the amplitude modulation.
In another exemplary embodiment 1400 shown generally in FIG. 14, the sweeping and computation described with respect to FIG. 12 can be performed. The LO can be taken from the forward power (FP). The FP can be filtered to reduce the effect of the interferer on the LO. In this embodiment, the RF coupler and the bandpass filter can be integrated, such as made from the same ceramic structure.
In the embodiments of 1200-1400, the sensed DC voltage thru the ADC can be used to control the ph1 and the ph2. When the ph1, ph2 is such that the DC voltages are maximized, then the two signals into the mixer are deemed to be in-phase. Ph1 can be adjusted to increase or otherwise make optimum the forward power measurement. Ph2 can also be adjusted to increase or otherwise make optimum the reflected power measurement. The power can be detected when phase difference between the two inputs of the mixer is zero degrees. These exemplary embodiments can ensure that the phase difference does not contribute to the power measurements. The RL can be calculated from the power measurements, and the phase difference is equal to ph2−ph1. The phase difference can be computed after power measurements have been determined for stable phase error measurement. A limiter can remove amplitude modulation on a transmitted signal (desired or undesired modulation). The limiter can act as a filter on forward power signal. Interfering signals may act to increase jitter on FP clock into mixer and can generate odd harmonics. A phase delay can be utilized in measured RF signal path to ensure that the ph1 and ph2 do not go negative. An amplifier can be utilized, but in one embodiment the amplifier can be utilized for only the dynamic range requirements of the mixer. A baseband low pass filter can reject interferers outside of the filter bandwidth. The LPF can also be used to filter out the AM on the modulated signal. If the AM remains, forward and reflected signal can be sampled at the same time. Multiple samples can also be utilized to avoid nulls.
In exemplary embodiment 1500 shown generally in FIG. 15, bandpass and low pass filter(s) (BPF and LPF) can be utilized with a shared limiter. The shared limiter can be utilized to reduce phase error between transmit and reflected measurements. Various other components and configurations can also be utilized to reduce current drain and/or reduce die area. This embodiment allows obtaining data based on filtered forward power.
In exemplary embodiment 1600 shown generally in FIG. 16, bandpass and low pass filter(s) (BPF and LPF) can be utilized with a shared delay clock. The shared delayed clock can be utilized to allow for phase difference to be determined by ph2 only. While not shown, a bandpass filter can be utilized, along with one or more other components described in FIGS. 12-15. In one example, embodiment 1600 can utilize a phase-shifted LO from the forward power for the reverse power.
FIG. 17 illustrates an example of timing that can be utilized for one or more of the tuning embodiments described herein, such as for a GSM/EDGE device. Forward and reverse power measurements can be made at the time periods indicated in time slots three and four. If the power detected outside of the transmission burst is above a threshold, then the measurement made during a burst can be deemed invalid. In this embodiment, frames are 4.615 ms and slots are 577 us, however other time periods may also be utilized.
FIG. 18 illustrates an example of timing that can be utilized for one or more of the tuning embodiments described herein, such as for a WCDMA device. Forward and reverse power measurements can be made at the time periods indicated in FIG. 18. If the power detected outside of the transmission burst is above a threshold, then the measurement made during the transmission can be deemed invalid.
A number of techniques can be utilized for validating return loss measurements. Measurements can be deemed invalid if: multiple fast measurements of the reflected port are taken and amplitude variations are detected which exceed the known envelope modulation; multiple fast measurements of transmit minus reflected values show amplitude variations (this method can cancel the transmit modulation and detects an interfering beat note); and multiple fast measurements are taken during transmission, excessive phase variation between measurements can be indicative of an interferer, and if the range of measurements exceeds a set threshold. In one embodiment, when using a “one step” tuning method, which uses impedance measurement to tune to a known match, not seeing a RL after the adjustment within an expected threshold would invalidate the tuning step, and the algorithm would then return to the last known good tuning state.
Additional validity methods, such as through use of peak and average detectors. For example, forward and reverse measurements are done with both Peak and Average detectors and compared. If the error exceeds the expected (modulation) peak-to-average ratio by a set threshold, measurements are deemed invalid. Using Peak and Average detection on the forward minus reverse summed signal can cancel the transmitted modulation and any difference should be due to interference, and thus compared to a set threshold for invalidity.
In exemplary embodiment 1900 shown generally in FIG. 19, a Costas Loop can be utilized where the forward power is relied upon to lock the local oscillator. The LPF in front of the LO can be set at a low enough frequency to strip off the angle modulation of the TX waveform. In another embodiment, a filter in the forward power path and/or in the reverse power path can be utilized. In another embodiment, where the level of the interferer is low enough, no filter may be needed. Embodiment 1600 can utilize an internal LO that is phase-locked to the forward power without the need for an external LO.
From the foregoing descriptions, it would be evident to an artisan with ordinary skill in the art that the aforementioned embodiments can be modified, reduced, or enhanced without departing from the scope and spirit of the claims described below. For example, the detection of an interferer can be used to determine whether even to perform the algorithm that determines the tunable state. For example, the detection of an interferer can result in the device determining a tuning state based on open-loop feedback rather than closed-loop feedback. Additionally, one or more of the steps described herein can be performed by a component of the transceiver. This can include incorporating particular components into the transceiver or utilizing already existing components of the transceiver. Other suitable modifications can be applied to the present disclosure. Accordingly, the reader is directed to the claims for a fuller understanding of the breadth and scope of the present disclosure.
FIG. 20 depicts an exemplary diagrammatic representation of a machine in the form of a computer system 2000 within which a set of instructions, when executed, may cause the machine to perform any one or more of the methodologies discussed above. In some embodiments, the machine operates as a standalone device. In some embodiments, the machine may be connected (e.g., using a network) to other machines. In a networked deployment, the machine may operate in the capacity of a server or a client user machine in server-client user network environment, or as a peer machine in a peer-to-peer (or distributed) network environment.
The machine may comprise a server computer, a client user computer, a personal computer (PC), a tablet PC, a laptop computer, a desktop computer, a control system, a network router, switch or bridge, or any machine capable of executing a set of instructions (sequential or otherwise) that specify actions to be taken by that machine. It will be understood that a device of the present disclosure includes broadly any electronic device that provides voice, video or data communication. Further, while a single machine is illustrated, the term “machine” shall also be taken to include any collection of machines that individually or jointly execute a set (or multiple sets) of instructions to perform any one or more of the methodologies discussed herein.
The computer system 2000 may include a processor 2002 (e.g., a central processing unit (CPU), a graphics processing unit (GPU, or both), a main memory 2004 and a static memory 2006, which communicate with each other via a bus 2008. The computer system 2000 may further include a video display unit 2010 (e.g., a liquid crystal display (LCD), a flat panel, a solid state display, or a cathode ray tube (CRT)). The computer system 2000 may include an input device 2012 (e.g., a keyboard), a cursor control device 2014 (e.g., a mouse), a disk drive unit 2016, a signal generation device 2018 (e.g., a speaker or remote control) and a network interface device 2020.
The disk drive unit 2016 may include a machine-readable medium 2022 on which is stored one or more sets of instructions (e.g., software 2024) embodying any one or more of the methodologies or functions described herein, including those methods illustrated above. The instructions 2024 may also reside, completely or at least partially, within the main memory 2004, the static memory 2006, and/or within the processor 2002 during execution thereof by the computer system 2000. The main memory 2004 and the processor 2002 also may constitute machine-readable media.
Dedicated hardware implementations including, but not limited to, application specific integrated circuits, programmable logic arrays and other hardware devices can likewise be constructed to implement the methods described herein. Applications that may include the apparatus and systems of various embodiments broadly include a variety of electronic and computer systems. Some embodiments implement functions in two or more specific interconnected hardware modules or devices with related control and data signals communicated between and through the modules, or as portions of an application-specific integrated circuit. Thus, the example system is applicable to software, firmware, and hardware implementations.
In accordance with various embodiments of the present disclosure, the methods described herein are intended for operation as software programs running on a computer processor. Furthermore, software implementations can include, but not limited to, distributed processing or component/object distributed processing, parallel processing, or virtual machine processing can also be constructed to implement the methods described herein.
The present disclosure contemplates a machine readable medium containing instructions 2024, or that which receives and executes instructions 2024 from a propagated signal so that a device connected to a network environment 2026 can send or receive voice, video or data, and to communicate over the network 2026 using the instructions 2024. The instructions 2024 may further be transmitted or received over a network 2026 via the network interface device 2020.
While the machine-readable medium 2022 is shown in an example embodiment to be a single medium, the term “machine-readable medium” should be taken to include a single medium or multiple media (e.g., a centralized or distributed database, and/or associated caches and servers) that store the one or more sets of instructions. The term “machine-readable medium” shall also be taken to include any medium that is capable of storing or encoding a set of instructions for execution by the machine and that cause the machine to perform any one or more of the methodologies of the present disclosure.
The term “machine-readable medium” shall accordingly be taken to include, but not be limited to: solid-state memories such as a memory card or other package that houses one or more read-only (non-volatile) memories, random access memories, or other re-writable (volatile) memories; magneto-optical or optical medium such as a disk or tape; and/or a digital file attachment to e-mail or other self-contained information archive or set of archives is considered a distribution medium equivalent to a tangible storage medium. Accordingly, the disclosure is considered to include any one or more of a machine-readable medium or a distribution medium, as listed herein and including art-recognized equivalents and successor media, in which the software implementations herein are stored.
Although the present specification describes components and functions implemented in the embodiments with reference to particular standards and protocols, the disclosure is not limited to such standards and protocols. Each of the standards for Internet and other packet switched network transmission (e.g., TCP/IP, UDP/IP, HTML, HTTP) represent examples of the state of the art. Such standards are periodically superseded by faster or more efficient equivalents having essentially the same functions. Accordingly, replacement standards and protocols having the same functions are considered equivalents.
The illustrations of embodiments described herein are intended to provide a general understanding of the structure of various embodiments, and they are not intended to serve as a complete description of all the elements and features of apparatus and systems that might make use of the structures described herein. Many other embodiments will be apparent to those of skill in the art upon reviewing the above description. Other embodiments may be utilized and derived therefrom, such that structural and logical substitutions and changes may be made without departing from the scope of this disclosure. Figures are also merely representational and may not be drawn to scale. Certain proportions thereof may be exaggerated, while others may be minimized. Accordingly, the specification and drawings are to be regarded in an illustrative rather than a restrictive sense.
Such embodiments of the inventive subject matter may be referred to herein, individually and/or collectively, by the term “invention” merely for convenience and without intending to voluntarily limit the scope of this application to any single invention or inventive concept if more than one is in fact disclosed. Thus, although specific embodiments have been illustrated and described herein, it should be appreciated that any arrangement calculated to achieve the same purpose may be substituted for the specific embodiments shown. This disclosure is intended to cover any and all adaptations or variations of various embodiments. Combinations of the above embodiments, and other embodiments not specifically described herein, will be apparent to those of skill in the art upon reviewing the above description.
The Abstract of the Disclosure is provided to allow the reader to quickly ascertain the nature of the technical disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims. In addition, in the foregoing Detailed Description, it can be seen that various features are grouped together in a single embodiment for the purpose of streamlining the disclosure. This method of disclosure is not to be interpreted as reflecting an intention that the claimed embodiments require more features than are expressly recited in each claim. Rather, as the following claims reflect, inventive subject matter lies in less than all features of a single disclosed embodiment. Thus the following claims are hereby incorporated into the Detailed Description, with each claim standing on its own as a separately claimed subject matter. It is also contemplated that features in one embodiment may be utilized with features of another embodiment.

## Claims

1. A matching network, comprising:
a tunable reactance circuit configured to be coupled to at least one of a transmitter portion and a receiver portion of a communication device, wherein the tunable reactance circuit is adjustable to a plurality of tuning states, wherein the determination of one of the plurality of tuning states is based on parameters associated with a detected interference, and wherein the tunable reactance circuit is adjusted based on a last known tuning state of the plurality of tuning states when the interference is determined to be not present.

2. The matching network of claim 1, wherein the tunable reactance circuit comprises at least one of one or more voltage tunable capacitors, one or more semiconductor varactors, one or more micro-electro-mechanical systems (MEMS) varactors, one or more semiconductor switched capacitors, one or more MEMS switched capacitors, and one or more ferroelectric capacitors.

3. The matching network of claim 1, further comprising a signal sampling network, wherein a signal output of the signal sampling network has a filter coupled thereto.

4. The matching network of claim 3, wherein the signal sampling network comprises a directional coupler.

5. The matching network of claim 1, wherein the determination of the one tuning state is based on information from at least one of an open-loop or closed-loop feedback configuration of the tunable reactance circuit.

6. The matching network of claim 5, wherein the tunable reactance circuit is operable to:
change the one tuning state to a different one of the plurality of tuning states based on the information from the at least one of the open-loop or closed-loop feedback configuration when detected signal measurements are determined to be valid; and
utilize one of a last known valid tuning state or a default tuning state when the detected signal measurements are invalid.

7. The matching network of claim 5, wherein the parameters associated with the detected interference are determined utilizing at least one of Voltage Standing Wave Ratio (VSWR) data measured over a period of time, amplitude modulation, a reflected input measured during transmission and non-transmission, phase measurements outside of a standard deviation, a comparison of measured and predicted transmission power level changes, and a comparison of measured and predicted improvement in reflected loss between the plurality of tuning states.

8. The matching network of claim 5, wherein the tunable reactance circuit comprises at least one of one or more capacitors with a tunable dielectric constant, and one or more capacitors of a fixed capacitance controlled by one of one or more micro-electromechanical systems (MEMS) switches and one or more semiconductor switches.

9. The matching network of claim 5, wherein a determination of invalidity of detected measurements is caused by a mobile device generating a signal that interferes with the communication device.

10. The matching network of claim 5, wherein a determination of invalidity of detected measurements is caused by internal interference generated by the communication device.

11. A matching network, comprising:
a tunable reactance circuit configured to be coupled to at least one of a transmitter portion and a receiver portion of a communication device, wherein the tunable reactance circuit is adjustable to a plurality of tuning states, wherein the determination of one of the plurality of tuning states is based on detecting interference with the communication device, and wherein the tunable reactance circuit is adjusted based on a last known tuning state of the plurality of tuning states when the interference is determined to be not present.

12. The matching network of claim 11, wherein the detecting of the interference is based on at least one of Voltage Standing Wave Ratio (VSWR) data measured over a period of time, amplitude modulation, a reflected input measured during transmission and non-transmission, phase measurements outside of a predetermined deviation, a comparison of measured and predicted transmission power level changes, and a comparison of measured and predicted improvement in reflected loss.

13. An apparatus for a communication device, the apparatus comprising a controller to determine a tuning state of a variable matching network that controls one or more operational characteristics of one of a receiver portion and a transmitter portion of the communication device, wherein the controller performs operations comprising:
detecting an existence of an interferer;
determining the tuning state based on whether the interferer exists and based on information from at least one of an open-loop or closed-loop feedback configuration;
changing the tuning state to a different tuning state based on the information from the closed-loop feedback configuration when the interferer does not exist; and
utilizing a previously determined tuning state when the interferer does exist.

14. The apparatus of claim 13, wherein the detecting of the existence of an interferer is based on at least one of Voltage Standing Wave Ratio (VSWR) data measured over a period of time, amplitude modulation, a reflected input measured during transmission and non-transmission, phase measurements outside of a predetermined deviation, a comparison of measured and predicted transmission power level changes, or a comparison of measured and predicted improvement in reflected loss.

15. The apparatus of claim 13, wherein the variable matching network comprises a voltage tunable dielectric and a directional coupler, wherein the directional coupler is operably connected with a filter.

16. A method comprising:
detecting interference with a communication device;
determining a tuning state of a variable matching network of the communication device based on parameters associated with the interference;
adjusting the variable matching network based on the determined tuning state; and
adjusting the variable matching network based on a last known tuning state when the interference is determined to be not present.

17. The method of claim 16, wherein the detecting of the interference is based on at least one of Voltage Standing Wave Ratio (VSWR) data measured over a period of time, amplitude modulation, a reflected input measured during transmission and non-transmission, phase measurements outside of a predetermined deviation, a comparison of measured and predicted transmission power level changes, or a comparison of measured and predicted improvement in reflected loss.

18. A method comprising:
detecting interference with a communication device, wherein the interference is sourced by another communication device; and
determining a tuning state of a variable matching network of the communication device based on the detected interference; and
adjusting the variable matching network based on a last known tuning state when the interference is determined to be not present.