Method and apparatus for improving co-channel operation of independent radio systems

Abstract

A method and apparatus for improving co-channel operation of independent radio systems operating simultaneously. The method and apparatus receive at least one signal, perform motion compensation correlation on the at least one signal, and determine a direction of arrival of the at least one signal. A response to the direction of arrival is implemented to improve co-channel operation of the radio system.

Description

Technical Field

[0001] Embodiments of the present invention relate generally to radio communications, and in particular, to methods and apparatus for providing co-channel operation of independent radio systems. Background Art

[0002] Radio frequency bands are becoming increasingly crowded with competing radio signals. Using various modulation techniques, such as code division multiplexing (CDM), frequency division multiplexing (FDM), orthogonal frequency division multiplexing (OFDM), quadrature amplitude modulation (QAM), time division multiplexing (TDM), or a combination thereof, has enabled transmitters and receivers to operate in the same frequency band, known as co-channel operation. However, signals with very low signal-to-noise ratios or those that do not use complex modulation schemes can be severely impacted by co-channel transmission.

[0003] In a recent case, 5G cellular signal transmitters were found to interfere with aircraft altimeters operating in the same frequency band. One of the frequency bands in which 5G systems operate is 3.7 GHz to 3.98 GHz, while certain aircraft altimeters used at altitudes less than 2,500 feet utilize the 4.2-4.4 GHz band. This type of altimeter is used for low-visibility approaches to airports when the aircraft is operating on autopilot. The proximity of the 5G operating frequency band to the altimeter frequency band resulted in erroneous altitude measurements. Interference with the accuracy of the aircraft altimeter could potentially compromise the operational safety of the aircraft.

[0004] Therefore, there is a need for a method and apparatus for improving co-channel operation of standalone radio systems. Summary of the Invention

[0005] According to one aspect of the present invention, a method for improving co-channel operation between multiple radio systems using a signal processing system is provided, comprising: receiving a first signal from a first remote source and a second signal from a second remote source at a receiver of the signal processing system, wherein the first signal and the second signal have the same or similar frequencies, causing the first signal to interfere with reception of the second signal; selecting one of the first signal and the second signal; correlating at least one local signal with the selected signal to generate at least one correlation result; determining the motion of an antenna of the receiver; generating a plurality of phasors each including a signal phase, wherein each phasor represents an estimate of a direction of arrival of the selected signal; compensating the phase of at least one of the at least one local signal, the selected signal, or at least one correlation result based on the plurality of phasors and the corresponding plurality of direction of arrival estimates to generate a plurality of phase-compensated correlation results; determining a phasor from the plurality of phasors that produces an optimized phase-compensated correlation result; identifying a direction of arrival of the selected signal using the determined phasor; determining one or more actions for improving reception of the second signal at the receiver from the direction of arrival of the selected signal; and performing the one or more actions.

[0006] In this manner, interference between a first signal (which may correspond to an undesired signal) and a second signal (which may correspond to a signal intended to be received by a signal processing system) at a receiver can be reduced. One or more actions utilize the determined direction of arrival to adjust the behavior of multiple radio systems (i.e., the first remote source, the second remote source, and / or the signal processing system) to improve reception of the second signal at the receiver. This reduces interference between these radio systems operating at similar frequencies, or in other words, improves co-channel operation of the radio systems.

[0007] The one or more actions may be any suitable operation that minimizes interference. In one example, the action may be switching the first remote source or the second remote source to a different frequency, or requesting the first remote source or the second remote source to switch to a different frequency. The determined direction of arrival may be used to identify the first remote source or the second remote source to make such a request.

[0008] The second remote source can be the original radiation source, i.e., a transmitter external to the signal processing system. Alternatively, the second remote source can be a reflection point of a signal transmitted by the transmitter of the signal processing system. In one example, the signal processing system is co-located with the radar system, and the second signal corresponds to a reflected radar signal used to determine the distance to the object. The first signal can also be a direct line-of-sight signal or a reflected signal. However, in any case, the first signal and the second signal originate from different transmitters.

[0009] The first signal and the second signal may have frequencies that are sufficiently similar for reception of the first signal to degrade the quality of (simultaneous) reception of the second signal at the receiver. In one example, the first signal and the second signal may be in adjacent frequency bands or in the same frequency band. The first signal and the second signal are preferably radio signals, and the first remote source and the second remote source are preferably wireless power sources.

[0010] The first signal and the second signal may also include deterministic codes for positioning calculations, such as Gold codes or other GNSS satellite codes.

[0011] One or more actions may be performed based on the direction of arrival calculated for only a selected one of the first and second signals. Alternatively, the direction of arrival may be determined for both signals in the same manner, or in other words, by performing the following additional steps: correlating at least one local signal with the remaining signal to generate at least one correlation result; determining the motion of the antenna; generating a plurality of phasors each comprising a signal phase, wherein each phasor represents an estimate of the direction of arrival of the remaining signal; compensating the phase of at least one of the at least one local signal, the remaining signal, or the at least one correlation result based on the plurality of phasors and the corresponding plurality of direction of arrival estimates to generate a plurality of phase-compensated correlation results; determining a phasor from the plurality of phasors that produces an optimized phase-compensated correlation result; and identifying the direction of arrival of the remaining signal using the determined phasor. In this case, one or more actions may be determined and performed based on the directions of arrival calculated for both the first and second signals.

[0012] Each phasor can be used to numerically represent the phase shift of a signal detected from a particular direction due to the motion of the antenna, compared to when there is no relative motion between the antenna and the signal. In this sense, each phasor can represent and be referred to as a "hypothesis" of the direction of arrival of the signal, as referred to elsewhere in this specification.

[0013] The signal phase in each phasor represents the direction of arrival of the selected signal. The signal phase may also include a phase component corresponding to the motion of the antenna. The step of generating a plurality of phasors may include generating, for each received signal, a set of phase hypotheses (or "phasors") associated with the motion of the antenna and a set of phase hypotheses (or "phasors") associated with the direction of arrival. Alternatively, the two sets of hypotheses may be combined into a single set of hypotheses that are tested simultaneously to determine the direction of arrival.

[0014] Preferably, one or more actions involve modifying a transmission pattern of the first signal or the second signal based on the identified direction of arrival, and / or modifying a sensitivity pattern of an antenna to improve reception of the second signal at the receiver. In this manner, by aligning a low-sensitivity or high-sensitivity region of the antenna with the direction of arrival of the first signal and / or the second signal, the gain or strength of the first signal can be reduced, or alternatively, the gain of the second signal can be increased. This minimizes the harmful interference effects of simultaneously receiving the first and second signals.

[0015] The transmission pattern can be a spatial antenna pattern, also known as a "radiation pattern," of the first remote source or the second remote source that can be changed to a different three-dimensional profile or rotated to a different orientation so that the main transmission lobe is directed toward or away from the antenna of the signal processing system. In a specific example, the antenna pattern can be changed from a typical sector pattern to a "knife-edge" pattern that is more heavily weighted toward a particular direction. The transmission pattern can also be a time pattern, in which transmissions are temporarily inhibited or "blanked" to prevent interference between the first signal and the second signal. In one example, transmission of the first signal can be inhibited for a predetermined time period or when the antenna and the first remote source are within a threshold distance. Similarly, the sensitivity pattern of an antenna can be spatially altered by redirecting or changing its radiation pattern. Alternatively, the sensitivity pattern can be temporarily altered by temporarily ignoring (or "blanking") signals received by the antenna.

[0016] Rotating or changing the antenna's radiation pattern can be performed mechanically (by physically moving the antenna) or digitally (e.g., using an electronic beam steering unit that drives a phased array antenna to change the antenna pattern), as known to those skilled in the art. Motion compensation can be used to artificially change or redirect the antenna pattern. For example, motion compensation can be used to adjust receiver parameters, such as frequency and rate, to enhance reception of desired signals arriving at the antenna from a particular direction, or to suppress reception of undesired signals arriving at the antenna from a different direction.

[0017] In one embodiment, the direction of arrival can be used to identify the source of the first signal. For example, the first signal may be transmitted by a 5G radio tower at a known location, in which case the determined direction of arrival of the first signal can be compared with the known location. An instruction can be sent to the identified source to temporarily disable transmission of the first signal. Alternatively, the direction of arrival can be used to determine that the source cannot be identified, in which case the sensitivity pattern of the antenna or receiver can be modified to avoid interference.

[0018] Preferably, the one or more determined actions include beam steering the antenna. In this way, the radiation pattern of the antenna can be aligned with the calculated direction of arrival of the first signal or the second signal to improve the reception or "gain" of the second signal at the receiver.

[0019] When selecting one of the first signal and the second signal includes selecting the second signal, beam steering the antenna preferably includes steering a main sensitivity lobe of the antenna toward the direction of arrival of the identified second signal. In this manner, the strength or gain of the received second signal can be increased because the antenna is redirected so that its most sensitive area or lobe is pointed toward the direction of arrival of the (desired) second signal.

[0020] When selecting one of the first signal and the second signal includes selecting the first signal, beam steering the antenna preferably includes steering a sensitivity null of the antenna toward the identified direction of arrival of the first signal. In this manner, the strength or gain of the received first signal can be reduced because the antenna is redirected so that one of its least sensitive areas is aligned with the direction of arrival of the (undesired) first signal. This indirectly improves reception or the signal-to-noise ratio of the second signal because the first signal is detected at a lower amplitude.

[0021] In embodiments where the directions of arrival of both the first and second signals are calculated, beam steering or adjustment of the antenna's radiation pattern may be performed to simultaneously align the direction of arrival of the first signal with the antenna's sensitivity null and the direction of arrival of the second signal with the main lobe. This may further reduce interference between the first and second signals.

[0022] The radiation pattern of the antenna can be steered or continuously changed to track the changing direction of arrival of the second remote source to account for movement between the antenna and the second remote source. This can be achieved by continuously recalculating the direction of arrival of the second signal. The recalculation of the direction of arrival can be determined based on a previous calculation, for example, based on incremental changes to a previous phasor in a plurality of phasors that produced an optimized phase compensation correlation result. This takes advantage of the fact that any change in the relative positioning of the antenna and the second remote source can be gradual, allowing for more efficient recalculation of the direction of arrival. Similarly, for example, the direction of arrival of the first signal can be continuously calculated in the same manner to repeatedly rotate or change the radiation pattern of the antenna to align the sensitivity null with the direction of arrival of the first signal.

[0023] Preferably, the one or more actions include sending a third signal to the first remote source or the second remote source to instruct the first remote source or the second remote source to take remedial action to improve reception of the second signal at the receiver. In this manner, the signal processing system can communicate with the remote source to resolve interference at the receiver. The remedial action can be any suitable measure to reduce interference at the receiver, such as switching to a different frequency or adjusting the transmission pattern of the first signal or the second signal.

[0024] Preferably, when the one or more actions include transmitting a third signal to the first remote source, the remedial action includes steering the first remote source's antenna beam away from the receiver or temporarily disabling transmission of the first signal. In this manner, the signal processing system can communicate with the first remote source to resolve interference at the receiver. The third signal can be used to inform the first remote source of the angular position of the signal processing system's antenna, allowing the first remote source to steer its own antenna's beam away from the signal processing system's antenna.

[0025] Preferably, the signal processing system is arranged in an aircraft. In this way, the method can be used to protect the aircraft from potentially dangerous interferences that could disrupt various operations of the aircraft, thereby posing a safety risk to the people on board.

[0026] Preferably, the second signal is a landing signal configured to assist in landing operations of the aircraft. In one example, the first remote source may be a 5G cellular network having an antenna mast near an airport. The receiver may be part of an altimeter radar on the aircraft, which may provide inaccurate altitude readings when the 5G system is transmitting at a nearby location. In this case, the second signal may be a signal emitted by the altimeter's transmitter that has been reflected from the ground back to the aircraft. An embodiment of the present invention may be implemented in an aircraft to determine the direction of arrival of a 5G signal from a nearby mast. The embodiment may control the altimeter's receive antenna pattern to reduce signal reception in the direction of the 5G mast, or may blank the altimeter operation to avoid erroneous altitude measurements that may put the aircraft in danger of crashing.

[0027] Preferably, the first signal is a 5G signal. In this way, interference caused by 5G signals (which may be a common signal type causing interference) can be reduced.

[0028] Preferably, the first signal and the second signal have a frequency difference of about 1 GHz or less. In one example, the first signal has a frequency of about 3.7 GHz to 3.98 GHz, and the second signal may have a frequency of about 4.2 GHz to 4.4 GHz.

[0029] Preferably, improving the reception of the second signal at the receiver comprises improving the signal-to-noise ratio of the second signal at the receiver.Improving the reception of the second signal at the receiver may also be referred to as improving the gain or strength of the second signal.

[0030] The invention may also be said to provide a method for reducing radio interference between two radio signals at a receiver.

[0031] According to a further aspect of the present invention, a signal processing system for improving co-channel operation between multiple radio systems is provided, comprising: a receiver, which includes an antenna, configured to receive a first signal from a first remote source and a second signal from a second remote source, the first signal and the second signal having the same or similar frequency so that the first signal can interfere with reception of the second signal at the receiver; and a controller, which is configured to: select one of the first signal and the second signal; correlate at least one local signal with the selected signal to generate at least one correlation result; determine the movement of the antenna; generate a plurality of phasors each including a signal phase, wherein each phasor represents an estimate of the direction of arrival of the selected signal; compensate the phase of at least one of the at least one local signal, the selected signal or at least one correlation result based on the plurality of phasors and the corresponding plurality of direction of arrival estimates to generate a plurality of phase-compensated correlation results; determine a phasor from the plurality of phasors that produces an optimized phase-compensated correlation result; use the determined phasor to identify the direction of arrival of the selected signal; determine one or more actions for improving reception of the second signal at the receiver from the direction of arrival of the selected signal; and perform one or more actions.

[0032] A non-transitory computer-readable medium storing executable instructions that, when executed by a computer, cause the computer to perform steps comprising: selecting one of a first signal received at a receiver from a first remote source and a second signal received at the receiver from a second remote source, the first signal and the second signal having the same or similar frequencies such that the first signal can interfere with reception of the second signal at the receiver; correlating at least one local signal with the selected signal to generate at least one correlation result; determining motion of an antenna of the receiver; generating a plurality of phasors each comprising a phase of the signal, wherein each phasor represents an estimate of a direction of arrival of the selected signal; compensating a phase of at least one of the at least one local signal, the selected signal, or the at least one correlation result based on the plurality of phasors and the corresponding plurality of direction of arrival estimates to generate a plurality of phase-compensated correlation results; determining a phasor from the plurality of phasors that produces an optimized phase-compensated correlation result; identifying a direction of arrival of the selected signal using the determined phasor; determining one or more actions for improving reception of the second signal at the receiver from the direction of arrival of the selected signal; and performing the one or more actions.

[0033] According to a further aspect of the present invention, a method for improving co-channel operation between multiple radio systems using a signal processing system is provided, comprising: receiving at least one signal from at least one remote source; correlating at least one local signal with at least one received signal to generate at least one correlation result; determining the motion of an antenna of the signal processing system; generating a plurality of phasors, wherein each phasor represents a hypothesis including a signal phase representing an estimate of an arrival direction of at least one received signal; compensating the phase of at least one of the local signal, at least one received signal, or at least one correlation result based on a plurality of hypotheses about the determined motion and arrival direction to generate a plurality of phase-compensated correlation results; determining a hypothesis from the plurality of hypotheses that optimizes at least one of the phase-compensated correlation results; identifying a direction of arrival of at least one received signal using the determined hypothesis; and determining a response to be applied to the at least one received signal from each direction of arrival of the at least one received signal to improve the co-channel operation.

[0034] According to a further aspect of the present invention, a method for improving co-channel operation between two radio systems is provided, the two radio systems including a first radio system transceiver having an antenna and a transceiver controller controlling an antenna pattern of the antenna, the method comprising receiving at least one signal from a remote source forming part of the second radio system, wherein the at least one signal is an undesired signal that interferes with the operation of the first radio system transceiver; correlating at least one local signal with at least one received signal to generate at least one correlation result; determining a motion of the antenna of the first radio system transceiver; generating a plurality of phasors, wherein each phasor represents a hypothesis including a signal phase representing an estimate of an arrival direction of the at least one received signal; compensating the phase of at least one of the local signal, at least one received signal, or at least one correlation result based on a plurality of hypotheses about the determined motion and arrival direction to generate a plurality of phase-compensated correlation results; determining a hypothesis from the plurality of hypotheses that optimizes at least one of the phase-compensated correlation results; identifying a direction of arrival of the at least one received signal using the determined hypothesis; and adjusting the antenna pattern using the transceiver controller to reduce signal reception of the undesired signal.

[0035] According to a further aspect of the present invention, there is provided an apparatus for performing signal correlation within a signal processing system, comprising at least one processor and at least one non-transitory computer-readable medium for storing instructions which, when executed by the at least one processor, cause the apparatus to perform operations comprising: receiving at least one signal from at least one remote source; correlating at least one local signal with at least one received signal to generate at least one correlation result; determining the motion of an antenna of the signal processing system; generating a plurality of phasors, wherein each phasor represents a hypothesis including a signal phase representing an estimate of an arrival direction of at least one received signal; compensating the phase of at least one of the local signal, at least one received signal, or at least one correlation result based on a plurality of hypotheses about the determined motion and arrival direction to generate a plurality of phase-compensated correlation results; determining a hypothesis from a plurality of hypotheses that optimizes at least one of the phase-compensated correlation results; identifying a direction of arrival of at least one received signal using the determined hypothesis; and determining, from each direction of arrival of at least one received signal, a response to be applied to at least one received signal to improve co-channel operation.

[0036] These and other features and advantages of the present disclosure may be understood from a review of the following detailed description of the disclosure, taken in conjunction with the accompanying drawings, in which like reference numerals refer to like parts throughout. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] So that the manner in which the above-described features of the present invention can be understood in detail, a detailed description of the invention may be made with reference to embodiments thereof, some of which are illustrated in the accompanying drawings. It should be noted, however, that the drawings illustrate only typical embodiments of this invention and are therefore not to be considered limiting of its scope, for the invention may admit to other equally effective embodiments.

[0038] Figure 1 A block diagram depicting a scenario in which two independent radio systems operate simultaneously in accordance with at least one embodiment of the present invention;

[0039] Figure 2 Describes an embodiment of the present invention Figure 1 A block diagram of a first radio system transceiver;

[0040] Figure 3 According to at least one embodiment of the present invention Figure 2 A flowchart of an operating method of the signal processing software; and

[0041] Figure 4 Describes an embodiment of the present invention Figure 2 Flowchart of the operating method of the control software. DETAILED DESCRIPTION

[0042] Embodiments of the present invention include apparatus and methods for improving co-channel operation of independent radio systems operating simultaneously. Many of today's radio communication systems utilize digital signals to improve communication throughput and security. Most of these systems utilize some form of deterministic digital code to facilitate signal acquisition, such as a Gold code. This digital code is determined by a receiver and broadcast by a transmitter to enable a communication receiver to find, obtain, and receive the transmitted signal. Using this deterministic code in combination with precise motion information of the receiver, embodiments of the present invention are useful for identifying the direction of arrival (DoA) of the signal propagation path between a receiver and a transmitter. The technique for determining DoA using receiver motion information is known as SUPERCORRELATION TM , and described in commonly assigned U.S. Patents 9,780,829, issued on October 3, 2017; 10,321,430, issued on June 11, 2019; 10,816,672, issued on October 27, 2020; U.S. Patent Publication No. 2020 / 0264317, published on August 20, 2020; and 2020 / 0319347, published on October 8, 2020, which are incorporated herein by reference in their entireties. Knowing the DoA of desired and / or undesired signals, a receiver can implement responses to improve co-channel performance. For example, a receiver can use the DoA to control the receive direction to do one or more of: improve reception of signals from certain transmitters (desired signals), reduce reception of signals from certain transmitters (undesired signals), or send a control signal to a transmitter so that the transmitter can take action to change device functionality at the transmitter. You can use, for example, SUPERCORRELATION TM technology or beam steering the antenna pattern to control the reception direction.

[0043] For example, if two radio systems are operating simultaneously in close proximity using the same or substantially the same channel (e.g., co-channel), a radio receiver or transceiver equipped with an embodiment of the present invention can control the antenna pattern of the receiver to avoid receiving signals in the direction of the transmitter that may interfere with reception when transmitting an undesired signal, and / or control the antenna pattern to improve reception of signals in the direction of the transmitter of the desired signal. In other embodiments, when the second transceiver may experience interference from the first radio system or may cause interference to the first radio system, the first radio system may notify the transceiver in the second radio system to stop transmitting or receiving, for example, the second radio system is "blanked" at an appropriate time and for an appropriate duration.

[0044] In a more specific example, the first radio system may be a 5G cellular network with an antenna mast near an airport. The second radio system may be an altimeter radar on an aircraft, which may provide inaccurate altitude readings when the 5G system is transmitting. An embodiment of the present invention may be juxtaposed with an aircraft to determine the DoA of a 5G signal from a nearby mast. The embodiment may control the altimeter antenna pattern to reduce signal reception in the direction of the 5G mast, or may blank the altimeter operation. Further improvements to the altimeter application may be made by using an altimeter antenna pattern with a fan-shaped pattern directed towards the ground, perpendicular to the aircraft's motion path. Such a pattern facilitates the use of very short blanking periods when an aircraft passes a 5G mast at high speeds (e.g., 250KPH to 300KPH). In a further embodiment, a transceiver using an embodiment of the present invention may send a signal to a 5G transmitter, and the transmitter may adjust its antenna pattern to avoid transmitting towards the aircraft.

[0045] A transceiver or receiver using this embodiment of the present invention can be manufactured to operate at lower transmit power, thereby reducing overall component cost and / or extending battery life. This improvement is useful in mobile devices that utilize communication technologies using deterministic codes (such as, but not limited to, WiFi, Bluetooth, cellular phones, and the like).

[0046] Figure 1 A block diagram depicts a scenario 100 according to one embodiment of the present invention, wherein two independent radio systems 122 and 124 (e.g., system 122 represented by first radio system transceivers 102 and 104, and system 124 represented by second radio system transceiver 106) operate simultaneously. In this exemplary embodiment, first radio transceiver 102 (a remote source) is transmitting a desired signal 108 to mobile first radio signal transceiver 104, while second radio system transceiver 106 (another remote source) is transmitting an undesired signal 110. Signals 108 and 110 are transmitted in the same frequency band or substantially the same frequency band (i.e., co-channel), such that if both signal 108 and signal 110 were received by mobile transceiver 104, transceiver 104 would not be able to receive desired signal 108. In one embodiment, first radio system transceiver 102 may be a fixed base station communicating with at least one mobile device (represented by mobile transceiver 104).

[0047] The mobile first radio system transceiver 104 includes a transceiver controller 118 operating in accordance with an embodiment of the present invention to respond to received signals to improve co-channel operation of the radio system. As described in detail below, the transceiver controller 118 uses SUPERCORRELATION as described in commonly assigned U.S. Patents 9,780,829, issued on October 3, 2017; 10,321,430, issued on June 11, 2019; 10,816,672, issued on October 27, 2020; U.S. Patent Publication 2020 / 0264317, published on August 20, 2020; and 2020 / 0319347, published on October 8, 2020. TM The present invention relates to a method for determining the direction of arrival (DoA) of received signals 108, 110, or both using a plurality of different techniques, which are incorporated herein by reference in their entirety. As the mobile transceiver 104 moves (represented by arrow 120), the transceiver controller 118 calculates motion information representing the motion of the mobile transceiver 104. The motion information is used to perform motion-compensated correlation on the received signals 108 and / or 110. Based on the motion-compensated correlation process, the transceiver controller 118 estimates the DoA of the signals 108 and / or 110.

[0048] Based on one or more signal DoAs, the transceiver controller 118 can respond to improve co-channel operation between the systems 122 and 124. In one embodiment, the response can be to modify the antenna pattern 112 of the transceiver 104, such as by beam steering. The pattern modification can steer the main lobe 114 toward the desired signal DoA (signal 108) to enhance reception of the desired signal 108, or place an antenna pattern null 116 in the DoA of the undesired signal 110 to suppress reception of the undesired signal 110, or a combination of these two techniques.

[0049] In other embodiments, SUPERCORRELATION TM Techniques can be used to enhance or suppress reception of signals based on their DoA. The technique adjusts receiver parameters, such as frequency and frequency rate, to enhance reception of desired signals arriving at the antenna from a particular direction, or to suppress reception of undesired signals arriving at the antenna from a different direction.

[0050] In other embodiments, the transceiver response may be to blank the operation of the mobile transceiver during periods when the second radio system transceiver 106 is operating or the mobile transceiver 104 is in proximity to the second radio system transceiver 106 .

[0051] In an exemplary scenario, the desired signal 108 may be a reflected altimeter signal transmitted by the mobile transceiver 104 located on the aircraft. The transceiver controller 118 may respond by changing the antenna pattern to reduce the unwanted signal (e.g., the interfering 5G signal), switching to a knife-edge antenna pattern so that the interference period is insignificant to the mobile transceiver, and / or blanking the mobile transceiver 104 during the possible interference period.

[0052] In an alternative embodiment, where the radio systems are not completely independent, the mobile transceiver 104 may transmit a control signal (represented by path 126) to the second radio system transceiver 106 in response to the undesired signal 110. The control signal 126 may cause the transceiver 106 to change its antenna pattern to steer toward a null in the direction of the mobile transceiver 104 or to blank its transceiver operation when in proximity to the first radio system transceiver 104. Generally speaking, the transceiver 106 responds to the control signal 126 in order to reduce the probability of interfering with the operation of the first radio system 122.

[0053] Figure 2 Describes an embodiment of the present invention Figure 1 FIG2 is a block diagram of a first radio system transceiver 104. The first radio system transceiver 104 includes a mobile platform 200 and an antenna 202. The mobile transceiver 104 may form part of a mobile computing system in a laptop, mobile phone, tablet computer, Internet of Things (IoT) device, unmanned aerial vehicle, autonomous vehicle, or human-operated vehicle, and the like. In general, embodiments of the present invention may find use in any environment where a mobile transceiver is used and may experience interference from another radio system operating in a co-channel manner.

[0054] In a typical mobile transceiver, the mobile platform 200 and the antenna 202 are an inseparable unit (eg, a mobile phone), where the antenna 202 moves with the mobile platform 200. TM The operation of the technology is based on the motion of the signal receiving antenna. Any reference to motion or transceiver motion described herein refers to the motion of antenna 202. In some embodiments, antenna 202 may be separate from mobile platform 200. In this case, the motion estimate used in the motion compensation process is the motion of antenna 202. In most scenarios, the motion of mobile platform 200 is the same as the motion of antenna 202, and therefore, the following description will assume that the motion of platform 200 and antenna 202 is the same.

[0055] Mobile platform 200 includes a transceiver 204, a signal processing and control system 208, and a motion module 222. Transceiver 204 includes an antenna controller 206, which facilitates antenna pattern control, i.e., antenna pattern beam steering. Antenna controller 206 can be a mechanical antenna steering mechanism, or more likely an electronic beam steering unit, which drives a phased array antenna to change the antenna pattern, as is known to those skilled in the art.

[0056] Signal processing and control system 208 includes at least one processor 210, support circuits 212, and memory 214. The at least one processor 210 can be any form of processor or combination of processors, including but not limited to a central processing unit, a microprocessor, a microcontroller, a field programmable gate array, a graphics processing unit, a digital signal processor, and the like. Support circuits 212 can include well-known circuits and devices that facilitate the functionality of one or more processors. Support circuits 212 can include one or more of a power supply, clock circuits, analog-to-digital converters, communication circuits, cache memory, and / or the like, or a combination thereof.

[0057] The memory 214 comprises one or more forms of non-transitory computer readable media, including one or more of read-only memory or random access memory, or any combination thereof. The memory 214 stores software and data, including, for example, signal processing software 216, control software 218, and data 220. The signal processing software 216, when executed by the one or more processors 210, performs motion compensated correlation on the received signals to estimate the DoA of the received signals. In one embodiment, the signal processing may be applied only to the signals of interest, i.e., the signal from the first radio system and the signal from the second radio system, so that the processing is focused on specific signal sources to improve the co-channel operation of the system. In other embodiments, the signal processing may process all received signals to achieve improved signal reception at the first radio system transceiver in view of many co-channel systems operating simultaneously. The following is about Figure 3 The motion compensation related process is described in detail. The signal processing software 216 and the control software 218 operate together as Figure 1 The transceiver controller 118 is configured to:

[0058] The DoA information is used by control software 218 to implement responses to received signals, such as adjusting antenna patterns, blanking transceivers, etc. Data 220 stored in memory 214 may also include signal estimates, correlation results, motion compensation information, motion information, position information, and the like.

[0059] The motion module 222 generates motion estimates for the transceiver 104. The motion module may include an inertial navigation system (INS) and a global navigation satellite system (GNSS), such as GPS, GLONASS, GALILEO, DEIBOU, etc. The INS may include, but is not limited to, one or more of a gyroscope, a magnetometer, an accelerometer, and the like, and may also include other devices not typically associated with an INS system, such as an altimeter. To facilitate motion compensation correlation, the motion module 222 generates motion information (sometimes referred to as a motion model) that includes at least the velocity of the antenna 202 in the direction of the transmitter of interest (i.e., the direction of the desired or undesired signal propagation path). The motion information may also include estimates of the pitch, roll, and yaw of the platform 200 / antenna 202, as well as the heading (direction of travel) of the platform 200 / antenna 202.

[0060] Figure 3 is a flow chart of a method 300 of operating the signal processing software 216 according to at least one embodiment of the present invention. The method 300 may be implemented in software, hardware, or a combination of both (e.g., using Figure 2 signal processing and control system 208).

[0061] Method 300 begins at 302 and continues to 304, where at a receiver, a Figure 1 The described method receives signals from multiple remote sources (e.g., transmitters such as a first radio system transceiver and a second radio system transceiver). The received signals include synchronization codes, such as Gold codes, extracted from radio frequency (RF) signals received at an antenna. The processes of down-converting RF signals and extracting codes are well known in the art. At 306, method 300 receives signals from a plurality of remote sources (e.g., transmitters such as a first radio system transceiver and a second radio system transceiver). Figure 2 The motion module 222 receives motion information. The motion information includes Figure 1 An estimate of the motion of the mobile transceiver 104 .

[0062] At 308, method 300 generates multiple phasor hypotheses related to the directions of interest of the received signal. Signal processing correlates at least one local code (at least one local signal) with at least one code extracted from the received RF signal. If multiple received signals are being processed, multiple local signals are generated. The phasor hypotheses are used to adjust the carrier phase of the local code relative to the extracted code with sub-wavelength accuracy. This adjustment or compensation can be performed by adjusting the phase of the local oscillator signal, the received signal, or the correlation result. For each received signal, at 310, method 300 correlates the received signal with the local signal using a set of (or multiple) motion hypotheses containing estimates of the phase offset required to accurately correlate the received signal with the local signal. Once the motion-compensated correlation is complete, the received signal is correlated with the local signal using phasors representing the DoA hypotheses to determine the received signal's direction of arrival. In one embodiment, for each received signal, there is a set of hypotheses (including a set of phase hypotheses related to antenna motion and a set of phase hypotheses related to the direction of arrival). In another embodiment, these two sets of hypotheses can be combined into a single set of hypotheses that are all tested simultaneously.

[0063] Motion estimation is typically a hypothesis of motion in the direction of interest, such as the direction of the transceiver emitting the received signal. At initialization, the direction of interest may be unknown or inaccurately estimated. Therefore, a brute-force search technique can be used to identify the direction of interest by searching in all directions and correlating the signals received in all directions. Comparing the correlation results in all directions enables method 300 to narrow the search space in the direction of the transceiver of interest. Using an iterative process, the search space is narrowed and a DoA estimate is determined. There is a strong correlation between the true values ​​of these hypotheses between code repetitions, so the initial search can be intensive, but subsequent processing only requires tracking parameters in the system as they evolve over time. Consequently, subsequent compensation is performed over a narrower search space.

[0064] In one embodiment, if a signal from a given transceiver was previously received, the set of hypotheses for the newly received signal includes a set of phasor hypotheses using the expected Doppler and Doppler rate and / or the last Doppler and Doppler rate used in receiving the previous signal from the transceiver. These values ​​can be centered around the last value used, or the last value used can be additionally offset by predictions of further offsets based on expected motion of the mobile transceiver. Each phasor representation includes a hypothesis of the signal phase representing an estimate of the direction of arrival of at least one received signal. At 310, the method 300 correlates each received signal with the set of hypotheses for that signal. These hypotheses are used as parameters to form a phase compensation phasor that phase compensates the correlation process with sub-wavelength accuracy. Thus, phase compensation can be applied to the received signal, a local frequency source (e.g., an oscillator), or a correlation value. The hypotheses collectively form N V The search space is a function of the number of hypotheses N and V, where N is the number of hypotheses and V is the number of variables to be defined. In addition to searching over the direction of arrival space and the transceiver motion compensation space, method 300 can also apply hypotheses related to other parameters (such as oscillator frequency) to correct for frequency and / or phase drift. Other variables may include heading to ensure that the correct motion compensation is applied. The result of the correlation process is a plurality of phase-compensated correlation results—one phase-compensated correlation value for each hypothesis for each received signal.

[0065] At 312, method 300 processes the correlation results to find the "best" or optimal result for each received signal. In one embodiment, method 300 generates a joint correlation output as a function (e.g., a sum) of multiple correlation values ​​generated by all hypotheses for a given received signal. The joint correlation output can be a single value or multiple values ​​representing a parameter that provides the optimal or best correlation output. In one embodiment, a cost function is applied to each set of resulting correlation values ​​for each received signal to find the optimal correlation output that represents the most accurate set of variables used in the hypothesis.

[0066] At 314, method 300 identifies the DoA of each received signal from the optimal correlation result of the signal. Thus, using motion compensated correlation enables the mobile transceiver to identify the direction of arrival of the received signal. Method 300 ends at 316.

[0067] In other embodiments, rather than using the maximum magnitude correlation value, other test criteria may be used. For example, method 300 may monitor the progress of the correlation as hypotheses are tested and apply a cost function indicating the best hypothesis or hypotheses when the cost function reaches a minimum (e.g., a small Hamming distance between peaks in the correlation graph). Thus, the joint correlation output may be a joint correlation value or a set of values. In other embodiments, additional hypotheses may be tested in addition to the direction hypothesis, for example to ensure that motion compensation parameters (i.e., velocity and heading) are correct.

[0068] Figure 4 A flow chart depicts a method 400 of operating the control software 218 according to an embodiment of the present invention. Method 400 begins at 402 and continues to 404, where method 400 receives a direction of arrival and signal information, such as a desired signal or an undesired signal. At 406, method 400 determines a response based on the signal information, i.e., steering the antenna pattern to maximize received signal strength if the signal is desired, or steering the antenna pattern to suppress received signal strength if the signal is undesired. At 408, method 400 implements the response and ends at 410.

[0069] Here, a number of examples have been given to illustrate various features and are not intended to be limiting. Any one or more of the features may not be limited to the specific examples presented herein, regardless of any order, combination, or connection described. In fact, it should be understood that any combination of the features and / or elements described above by way of example is contemplated, including any variations or modifications not listed but capable of achieving the same content. Unless otherwise specified, any one or more of the features may be combined in any order.

[0070] As mentioned above, the figures are presented herein for illustrative purposes and are not meant to impose any structural limitations unless otherwise specified. Various modifications to any structure shown in the figures are contemplated as being within the scope of the invention presented herein. The present invention is not intended to be limited to any scope of the claim language.

[0071] Where "coupled" or "connected" is used, unless otherwise specified, no limitation is implied: coupling or connection is limited to physical coupling or connection, and instead should be understood to include communicative coupling, including wireless transmissions and protocols.

[0072] Any block, step, module or other content described herein can represent one or more instructions, which can be stored as software on a non-transitory computer-readable medium and / or executed by hardware. Any such block, module, step or other content can be executed in a manner that can be automated by various software and / or hardware combinations, including using dedicated hardware designed to achieve such purposes. As described above, any number of blocks, steps or modules can be executed in any order, or not at all, including substantially simultaneously, i.e., within the tolerance range of the system executing the blocks, steps, or modules.

[0073] Where conditional language is used, including but not limited to "can," "could," "may," or "might," it should be understood that the associated feature or element is not required. Thus, where conditional language is used, elements and / or features should be understood as being optionally present in at least some instances and not necessarily conditional on anything unless otherwise specified.

[0074] Where a list is listed with alternatives or conjunctions (e.g., one or more of A, B, and / or C), unless otherwise specified, it should be understood to include one or more of each element, including any one or more combinations of any number of the listed elements (e.g., A, AB, AC, ABC, ABB, etc.). When "and / or" is used, it should be understood that these elements can be connected with alternatives or conjunctions.

[0075] While the foregoing is directed to embodiments of the present invention, other and further embodiments of the invention may be devised without departing from the basic scope thereof, and the scope thereof is determined by the claims that follow.

Claims

1. A method for improving co-channel operation between multiple radio systems using a signal processing system, comprising: receiving, at a receiver of the signal processing system, a first signal from a first remote source and a second signal from a second remote source, wherein the first signal and the second signal have the same or similar frequencies, causing the first signal to interfere with reception of the second signal; selecting one of the first signal and the second signal; correlating at least one local signal with the selected signal to generate at least one correlation result; determining motion of an antenna of the receiver; generating a plurality of phasors each comprising a signal phase, wherein each phasor represents a direction of arrival estimate of the selected signal; compensating a phase of at least one of the at least one local signal, the selected signal, or the at least one correlation result based on the plurality of phasors and the corresponding plurality of direction-of-arrival estimates to generate a plurality of phase-compensated correlation results; determining a phasor among the plurality of phasors that produces an optimized phase compensation correlation result; identifying a direction of arrival of the selected signal using the determined phasor; determining, from the direction of arrival of the selected signal, one or more actions for improving reception of the second signal at the receiver; and The one or more actions are performed.

2. The method according to claim 1, wherein: The one or more actions involve modifying a transmission pattern of the first signal or the second signal based on the identified direction of arrival, and / or modifying a sensitivity pattern of the antenna to improve reception of the second signal at the receiver.

3. The method according to claim 1 or 2, wherein: The one or more determined actions include beam steering the antenna.

4. The method according to claim 3, wherein: Selecting one of the first signal and the second signal includes selecting the second signal, and wherein beam steering the antenna includes steering a main sensitivity lobe of the antenna toward a direction of arrival of the identified second signal.

5. The method according to claim 3, wherein: Selecting one of the first signal and the second signal includes selecting the first signal, and wherein beam steering the antenna includes steering a sensitivity null of the antenna toward a direction of arrival of the identified first signal.

6. A method according to any one of the preceding claims, wherein: The one or more actions include sending a third signal to the first remote source or the second remote source to instruct the first remote source or the second remote source to take remedial action for improving reception of the second signal at the receiver.

7. The method according to claim 6, wherein: The one or more actions include transmitting the third signal to the first remote source, and the remedial action includes steering an antenna beam of the first remote source away from the receiver or temporarily disabling transmission of the first signal.

8. A method according to any one of the preceding claims, wherein: The signal processing system is arranged in an aircraft.

9. The method according to claim 8, wherein: The second signal is a landing signal configured to assist in a landing operation of the aircraft.

10. A method according to any one of the preceding claims, wherein: The first signal is a 5G signal.

11. A method according to any one of the preceding claims, wherein: The first signal and the second signal have a frequency difference of about 1 GHz or less.

12. A method according to any one of the preceding claims, wherein: Improving reception of the second signal at the receiver includes improving a signal-to-noise ratio of the second signal at the receiver.

13. A signal processing system for improving co-channel operation between multiple radio systems, comprising: a receiver comprising an antenna configured to receive a first signal from a first remote source and a second signal from a second remote source, the first signal and the second signal having the same frequency or frequencies such that the first signal can interfere with reception of the second signal at the receiver; and A controller configured to: selecting one of the first signal and the second signal; correlating at least one local signal with the selected signal to generate at least one correlation result; determining movement of the antenna; generating a plurality of phasors each comprising a signal phase, wherein each phasor represents a direction of arrival estimate of the selected signal; compensating a phase of at least one of the at least one local signal, the selected signal, or the at least one correlation result based on the plurality of phasors and the corresponding plurality of direction-of-arrival estimates to generate a plurality of phase-compensated correlation results; determining a phasor among the plurality of phasors that produces an optimized phase compensation correlation result; identifying a direction of arrival of the selected signal using the determined phasor; determining, from the direction of arrival of the selected signal, one or more actions for improving reception of the second signal at the receiver; and The one or more actions are performed.

14. A non-transitory computer-readable medium storing executable instructions, which, when executed by a computer, cause the computer to perform steps comprising: selecting one of a first signal received at a receiver from a first remote source and a second signal received at the receiver from a second remote source, the first signal and the second signal having the same or similar frequencies such that the first signal is capable of interfering with reception of the second signal at the receiver; correlating at least one local signal with the selected signal to generate at least one correlation result; determining motion of an antenna of the receiver; generating a plurality of phasors each comprising a signal phase, wherein each phasor represents a direction of arrival estimate of the selected signal; compensating a phase of at least one of the at least one local signal, the selected signal, or the at least one correlation result based on the plurality of phasors and the corresponding plurality of direction-of-arrival estimates to generate a plurality of phase-compensated correlation results; determining a phasor among the plurality of phasors that produces an optimized phase compensation correlation result; identifying a direction of arrival of the selected signal using the determined phasor; determining, from the direction of arrival of the selected signal, one or more actions for improving reception of the second signal at the receiver; and The one or more actions are performed.

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