Electromagnetic time-reversal beamforming system

Abstract

An electromagnetic time-reversal beamforming system is provided that can enhance signal integrity, robustness, and real-time adaptability in inter-vehicle communication networks. [Solution] The electromagnetic time-reversal beamforming system of the present invention comprises a rigid support frame (202) carrying spatially distributed antenna array elements, a radio frequency front-end compartment (206), a signal conditioning housing (210), a time-reversal processing unit (214), and a re-radiation subsystem (216).

Description

[Technical Field]

[0001] The present disclosure relates to the field of vehicular communication systems, and more particularly to an electromagnetic time-reversal beamforming system. In a more specific aspect, the present invention relates to an electromagnetic time-reversal beamforming system for enhancing signal integrity, robustness, and real-time adaptability in inter-vehicle networks. The system is configured for adaptive beamforming in inter-vehicle communications using electromagnetic time-reversal techniques to improve performance in multipath-prone and dynamic environments. [Background technology]

[0002] Vehicle-to-vehicle communications is a key requirement for next-generation autonomous driving networks, ensuring real-time, reliable, and low-latency communications essential for autonomous vehicle navigation, cooperative driving, safety alerts, and traffic coordination.

[0003] Existing beamforming systems are highly dependent on line-of-sight conditions and often perform poorly under multipath propagation or non-line-of-sight scenarios, such as urban intersections, tunnels, or dense traffic situations.

[0004] In various prior art, existing adaptive beamforming systems struggle to maintain signal fidelity in rapidly changing environments. Techniques such as multiple-input multiple-output, millimeter-wave beamsteering, and channel estimation have been used to improve performance, but they often introduce latency and require significant computational resources. From the above discussion, it is clearly depicted that there is a need for a vehicular communication system configured to perform adaptive beamforming in vehicle-to-vehicle communications using electromagnetic time reversal to improve performance in multipath prone and dynamic environments. Summary of the Invention [Problem to be solved by the invention]

[0005] This disclosure relates to an electromagnetic time-reversal beamforming system for enhancing signal integrity, robustness, and real-time adaptability in inter-vehicle communication networks. The proposed electromagnetic time-reversal beamforming system exploits time-reversal symmetry to dynamically reconstruct the original signal path in complex environments. The system is configured to record the incoming distorted wavefront, apply time-reversal, which is inverse filtering in the time domain, and retransmit the signal through the same channel. With the application of the proposed system, the wave retraces its path and coherently converges to the original signal source or intended receiver, despite scattering, reflection, and diffraction.

[0006] The present disclosure seeks to provide an electromagnetic time-reversal beamforming system. The system comprises: a multi-element antenna array having an RF front end configured to passively receive a highly distorted received electromagnetic signal; and a low-noise amplifier in the RF front end configured to amplify the received analog signal without significantly increasing noise, the low-noise amplifier connected to a plurality of analog-to-digital converters configured to digitize the amplified signal for digital processing; a pre-processing module configured to perform noise reduction and signal synchronization of the digitized signal, the pre-processing module using a plurality of digital filters to perform noise reduction and signal synchronization to align phase and timing across the plurality of antenna elements; a time-reversal processing module including a time-reversal signal processor configured to capture and digitally sample an incoming distorted waveform over a time window using a wavefront recorder and apply temporal filtering or inversion to the recorded signal; and an adaptive transmitter module connected to the time-reversal processing module and configured to re-transmit the time-reversed signal to ensure spatial and temporal focusing, the adaptive transmitter module configured to output a reliable, spatially focused, and interference-resistant vehicle-to-vehicle communication signal.

[0007] In one embodiment, the system further comprises: a beamforming control unit configured to receive the reversed signal and determine an optimal beamforming vector for steering the retransmitted signal, the beamforming control unit configured to utilize spatial information from the antenna array and vehicle telemetry to ensure phase-aligned transmission in the intended direction; an interference mitigation module operatively connected to the beamforming control unit and configured to refine the signal from the beamforming control unit, the interference mitigation module configured to suppress signals from undesired sources or directions using null steering and spatial filtering; and a channel estimation module configured to perform channel estimation concurrently with the time reversal, the channel estimation module configured to utilize pilot signals or feedback from the vehicles to all receivers. a power control module operably connected to the adaptive transmission module, the power control module configured to adjust the power level of the retransmitted time-reversed signal based on channel feedback and path loss estimation; and a calibration module configured to continuously monitor channel conditions and vehicle movement via on-board sensors and adjust beamforming parameters in real time, the calibration module configured to receive inputs from the interference mitigation module and the power control module, thereby performing adaptive optimization by adjusting beamwidth, adjusting time resolution, updating a channel model, and recalibrating antenna gain patterns.

[0008] An objective of the present disclosure is to provide an electromagnetic time-reversal beamforming system to enhance signal integrity, robustness, and real-time adaptability in inter-vehicle communication networks.

[0009] Another object of the present disclosure is to provide a system that exploits the time-reversal symmetry of Maxwell's equations to dynamically reconfigure the original signal path in a complex environment.

[0010] Another object of the present disclosure is to apply time reversal in the time domain to the received distorted wavefront and retransmit the signal over the same channel.

[0011] Another object of the present disclosure is to retransmit a wave so that it retraces its path and converges at the original source or intended receiver, even in the presence of scattering, reflection, and diffraction.

[0012] Furthermore, another object of the present disclosure is to address the limitations of conventional beamforming systems that transmit signals based on pre-calculated steering vectors.

[0013] To further clarify the advantages and features of the present disclosure, a more particular description of the present invention will be made by reference to specific embodiments thereof which are illustrated in the accompanying drawings. It is understood that these drawings depict only typical embodiments of the invention and are therefore not to be considered limiting of its scope. The invention will be described with additional specificity and detail through the use of the accompanying drawings. [Means for solving the problem]

[0014] To achieve the above object, the present invention provides an electromagnetic time-reversal beamforming system, comprising: a rigid support frame carrying spatially distributed antenna array elements, each antenna element mounted to the rigid support frame using an adjustable fixture to maintain a predefined geometric alignment and orientation, each antenna element physically connected to a modular radio frequency front-end compartment; a radio frequency front-end compartment, the radio frequency front-end compartment comprising a set of electromagnetically shielded enclosures, each containing a low-noise amplifier unit connected to a coaxial signal conduit from a corresponding antenna element, each amplifier unit further hard-wired to a signal digitization board including an analog-to-digital converter; a signal conditioning enclosure, the signal conditioning enclosure comprising a plurality of plug-in filter modules for analog and digital noise attenuation and a synchronization module including a timing crystal oscillator and a delay matching circuit, the plug-in filter modules the time-reversal processing unit is housed in a thermally managed chassis and includes a wavefront capture module having a high-speed sample-and-hold integrated circuit and a waveform storage array; and a re-radiation subsystem including a phased antenna transmitter array mounted on a connectable mechanical fixture to radiate the processed time-reversed signal toward a source of distortion in the input signal with high spatial and temporal coherence using physical signal routing paths and phase-calibrated antenna elements, each antenna of the phased antenna transmitter array being coupled via a digitally controlled phase shifter to an impedance-matched power amplifier located on an emission control board housed in a grounded metal casing. [Effects of the Invention]

[0015] The electromagnetic time-reversal beamforming system according to the present invention includes a rigid support frame (202) carrying spatially distributed antenna array elements, a radio frequency front-end compartment (206), a signal conditioning enclosure (210), a time-reversal processing unit (214), and a re-radiation subsystem (216). In this configuration, the electromagnetic time-reversal beamforming system can improve signal integrity, robustness, and real-time adaptability in inter-vehicle communication networks. [Brief explanation of the drawings]

[0016] These and other features, aspects, and advantages of the present disclosure will become better understood from the following detailed description when read in conjunction with the accompanying drawings.

[0017] FIG. 1 illustrates a block diagram of an electromagnetic time-reversal beamforming system according to one embodiment of the present disclosure. FIG. 2 shows a block diagram of an electromagnetic time-reversal beamforming system according to another embodiment of the present invention. FIG. 3 illustrates three time-domain plots visualizing signals at different operational stages of an electromagnetic time-reversal beamforming system according to an embodiment of the present disclosure; and FIG. 4 shows a plot depicting the effects of a Rayleigh fading channel and the benefits of time-reversal beamforming, in accordance with an embodiment of the present disclosure.

[0018] Additionally, those skilled in the art will appreciate that elements in the figures are illustrated for simplicity and may not necessarily be drawn to scale. For example, a flowchart illustrates a method in terms of the most prominent steps involved to help improve understanding of aspects of the present disclosure. Furthermore, with respect to device structure, one or more components of the device may be represented in the drawings by conventional symbols, and the drawings may show only certain details relevant to understanding embodiments of the present disclosure, so as not to obscure the drawings with details that will be readily apparent to one skilled in the art having the benefit of the description herein. DETAILED DESCRIPTION OF THE INVENTION

[0019] For the purposes of promoting an understanding of the principles of the invention, reference will now be made to the embodiments illustrated in the drawings and specific language will be used to describe them. Nevertheless, it will be understood that no limitation of the scope of the invention is thereby intended, and that such changes and further modifications in the illustrated system, and such further applications of the principles of the invention as illustrated therein, are contemplated as would normally occur to one skilled in the art to which the invention pertains.

[0020] It will be understood by those skilled in the art that the foregoing general description and the following detailed description are exemplary and explanatory of the invention, but are not intended to be restrictive thereof.

[0021] References throughout this specification to "one aspect," "another aspect," or similar language mean that a particular feature, structure, or characteristic described in connection with an embodiment is included in at least one embodiment of the present disclosure. Thus, the appearances of "in one embodiment," "in another embodiment," and similar phrases throughout this specification do not necessarily all refer to the same embodiment.

[0022] Composition, or other variations thereof, is intended to be non-exclusive inclusive, meaning that a process or method consisting of a list of steps does not include only those steps, but may include other steps not expressly listed or inherent in such process or method. Similarly, one or more devices or subsystems or elements or structures or components preceded by "consisting of..." does not, without more constraints, exclude the presence of other devices or subsystems or elements or structures or components, or additional devices or subsystems or elements or structures or components.

[0023] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The systems, methods, and examples provided herein are illustrative only and are not intended to be limiting.

[0024] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. FIG. 1 is a block diagram of an electromagnetic time-reversal beamforming system (100) according to one embodiment of the present disclosure.

[0025] Referring to FIG. 1, the system (100) comprises a multi-element antenna array (102) having an RF front end (104) configured to passively receive a highly distorted received electromagnetic signal; a plurality of low-noise amplifiers (106) disposed within the RF front end (104), each configured to amplify a received analog signal without significantly increasing noise, the low-noise amplifiers (106) connected to a plurality of analog-to-digital converters (108) configured to digitize the amplified signals for digital processing; a pre-processing module (110) configured to perform noise reduction and signal synchronization of the digitized signals, wherein a plurality of digital filters (110a) are used to perform noise reduction, and signal synchronization is performed to align phase and timing across the plurality of antenna elements; and a time-reversal processing module (112) including a time-reversal signal processor (112a) configured to capture and digitally sample an input distorted waveform over a time window using a wavefront recorder (112b) and apply time filtering or inversion to the recorded signal; and an adaptive transmit module (114) connected to the time-reversal processing module (112) and configured to retransmit the time-reversed signal to ensure spatial and temporal focusing, wherein the adaptive transmit module (114) is configured to output a reliable, spatially focused, and interference-resistant vehicle-to-vehicle communication signal.

[0026] In one embodiment, the system (100) further comprises: a beamforming control unit (116) configured to receive the inverted signal and determine an optimal beamforming vector for steering the retransmitted signal, the beamforming control unit (116) configured to utilize spatial information from the antenna array (102) and vehicle telemetry to ensure phased transmission in the intended direction; and an interference mitigation module (118) operably connected to the beamforming control unit (116), configured to improve a signal from the beamforming control unit (116), the interference mitigation module (118) configured to suppress signals from undesired sources or directions using null steering and spatial filtering; and a channel estimation module (120) configured to perform channel estimation concurrently with the time reversal, the channel estimation module (120) configured to utilize pilot signals or feedback from the vehicles to all receivers; and a power control module (122) operably connected to the adaptive transmit module (114), configured to adjust a power level of the retransmitted time-reversed signal based on the channel feedback and path loss estimates. A calibration module (124) configured to continuously monitor channel conditions and vehicle movement via on-board sensors and adjust beamforming parameters in real time, the calibration module (124) configured to receive inputs from the interference mitigation module (118) and the power control module (122) and thereby perform adaptive optimization by adjusting beamwidth, adjusting time resolution, updating channel models, and recalibrating antenna gain patterns.

[0027] In one embodiment, the system (100) further comprises a buffer memory (112c) configured to store the time-reversed signal for retransmission, the buffer (112c) memory being connected to the beamforming control unit (116) and the adaptive transmitter module (114).

[0028] 2 is a block diagram of an electromagnetic time-reversal beamforming system in accordance with another embodiment of the present invention. The system 200 consists of a rigid support frame 202 carrying spatially distributed antenna array elements 204, each mounted with adjustable fixtures to maintain a predefined geometric alignment and orientation, and each antenna element 204 physically connected to a modular RF front-end section 206.

[0029] The radio frequency front end compartment 206 consists of a set of electromagnetically shielded enclosures, each enclosing a low noise amplifier unit 208 connected to a coaxial signal conduit from a corresponding antenna element 204, and each low noise amplifier unit 208 is further hardwired to a signal digitization board containing an analog-to-digital converter implemented on a multi-layer printed circuit board structure.

[0030] The signal conditioning enclosure 210 consists of multiple plug-in filter modules 212 for analog and digital noise attenuation, and a synchronization module containing a timing crystal oscillator and delay matching circuitry, all electrically interfaced via ribbon cable or impedance-controlled microstrip to maintain phase matching across the signal lines from the multiple antenna channels.

[0031] System 200 further includes a time-reversal processing unit 214 housed in a thermally managed chassis, comprising a wavefront acquisition module with a high-speed sample-and-hold integrated circuit and a waveform storage array; and a re-radiation subsystem 216 comprising a phased antenna transmitter array mounted on a connectable mechanical fixture to radiate the processed time-reversed signal with high spatial and temporal coherence toward the source of the input signal distortion using physical signal routing paths and phase-calibrated antenna elements, each antenna of the transmitter array coupled through an impedance-matched power amplifier and digitally controlled phase shifter located on an emissions control board housed in a grounded metal casing.

[0032] In one embodiment, the chassis of the time reversal processing unit 214 includes an active thermal management system consisting of a network of miniature heat pipe assemblies, thermoelectric coolers, and integrated temperature sensors embedded beneath the processing rack and coupled to a finned aluminum heat sink array and axial fan system attached to the chassis frame to ensure operational stability of the heat-sensitive inversion circuitry.

[0033] In one embodiment, the signal digitization board is enclosed within a grounded conductive compartment lined with ferrite-based electromagnetic interference absorbing tiles, and all interconnecting conduits between the amplifier unit and the analog-to-digital converter are constructed using coaxial or twisted-pair shielded cable terminated with impedance-matching connectors to suppress parasitic coupling and maintain signal fidelity throughout the digitization path.

[0034] In one embodiment, each antenna element 204 in the spatially distributed array is secured to an angle adjustment subassembly consisting of a ball-and-socket joint, a threaded tension collar, and a locking clamp interface, allowing fine adjustment of azimuth and elevation angles to ensure beam alignment across a variety of vehicle or field deployment configurations.

[0035] In one embodiment, the low noise amplifier unit 208, analog-to-digital converter board, and plug-in filter module 212 are each mounted on a hot-swappable card edge connector system with keyed sockets and locking rails, allowing for rapid field replacement and minimizing system downtime during diagnostics or component upgrades.

[0036] In one embodiment, the system comprises an internal power conditioning assembly housed in a shielded enclosure, said assembly including a DC-DC converter, transient voltage suppressors, and a thermally fused power distribution bus, the power conditioning assembly mounted to an insulating damping plate and electrically interfaced to all active components via a color-coded modular wiring harness with electromagnetic interference gaskets and ground plane reference rails.

[0037] The present invention relates to an electromagnetic time-reversal beamforming system configured to perform time reversal on a received distorted signal. In contrast to conventional beamforming systems, which suffer from drawbacks such as multipath fading and signal distortion, the proposed system is configured to exploit time-reversal symmetry in electromagnetic wave propagation to reconstruct the distorted signal with sub-millisecond accuracy. The system is configured to capture the incident wavefront, perform inverse time filtering, and retransmit the signal in a phase-coherent manner. The system implementation aims to neutralize the effects of interference and multipath. The system includes a real-time adaptive calibration module configured to continuously optimize the beam pattern based on vehicle mobility, ensuring uninterrupted high-speed data exchange.

[0038] In one embodiment, the system comprises multiple components: a multi-element antenna array, multiple low noise amplifiers, multiple analog-to-digital converters, a pre-processing module, a temper reversal processing module a, a beamforming control unit, a channel estimation module, an interference mitigation module, a power control module, and a feedback and optimization component. Each component of the system is described in detail below.

[0039] The system consists of a multi-element antenna array configured to operate in the mmWave and THz frequency bands. The radio frequency front end includes components such as low-noise amplifiers, filters, and mixers. The antenna system passively receives incoming electromagnetic signals that are highly distorted due to multipath and line-of-sight conditions.

[0040] The low-noise amplifier amplifies the received analog signal, emphasizing weak signals without significantly increasing noise, and then passes the amplified analog signal through an analog-to-digital converter to convert it into a digital signal for digital processing. The high-speed analog-to-digital converter allows for accurate capture of high-frequency components.

[0041] The system is configured to pre-process the digitized signals, performing noise reduction and signal synchronization. Noise reduction is performed using digital filters to remove channel-induced thermal noise. Signal synchronization aligns phase and timing across multiple antenna elements. The pre-processing module ensures that the signals are clean and time-aligned before time reversal is applied.

[0042] The system is configured to perform time reversal using a time-reversal signal processor. The time-reversal signal processor configures the system to capture a received distorted waveform over a time window using a waveform recorder, which digitally samples the received distorted waveform over time. Time reversal is performed on the recorded waveform or signal, and the signal is stored in a buffer for retransmission. When retransmitted, the time-reversed waveform naturally converges to its original source point or intended direction due to the time-reversal symmetry of Maxwell's equations, effectively neutralizing multipath interference.

[0043] The system is configured to perform beamforming control, and the support system is configured to receive the inverted signal and determine the optimal beamforming vector to direct the retransmitted signal. The beamforming control unit uses spatial information from the antenna array and vehicle telemetry (e.g., position, velocity) to ensure phase-aligned transmission in the intended direction. The system is configured to perform channel estimation, which runs in parallel with the time reversal operation. To perform channel estimation, the system uses pilot signals or feedback from the vehicle to all receivers. The channel estimation provides key metrics such as path delay, fading characteristics, and Doppler shift. The channel response allows for refinement of the inverted signal and informs power and beam management decisions. The system is configured to perform interference mitigation, and the signal obtained after beamforming control is further refined by an interference mitigation module. The interference mitigation module is configured to suppress signals from unwanted sources or directions using null steering and spatial filtering techniques to ensure robustness in congested communication environments (e.g., traffic intersections).

[0044] The system is further configured to perform power control and retransmission of the signal, and based on the channel feedback and path loss estimation, the system performs power control by adjusting the power level of the retransmitted time-reversed signal to ensure focused energy towards the target receiver without violating any emissions regulations and without causing any interference.

[0045] The system includes a closed-loop module for performing feedback and optimization, configured to continuously monitor the environment and vehicle dynamics based on inputs received from the interference mitigation module and the power control module, and providing adaptive optimization by changing bandwidth, adjusting time resolution, updating channel models, and recalibrating antenna gain patterns. The closed-loop module ensures seamless communication even in high-speed or highly dynamic scenarios, such as tunnels, curving roads, and urban canyons.

[0046] In the final stage, the system is configured to output a reliable, spatially focused, and interference-resistant vehicle-to-vehicle communication signal that can be used for: autonomous vehicle-to-autonomous vehicle coordination, infrastructure communication (traffic lights, road signs), cloud-based vehicle analytics, safety warnings, and infotainment systems.

[0047] In an exemplary embodiment, the system comprises: a multi-band antenna array unit supporting millimeter-wave and terahertz bands and enabling high-resolution wave capture; a wavefront recorder configured to digitally sample distorted received waveforms over time; a time-reversal signal processor configured to apply inverse-time filtering to the received signals; an adaptive transmit module configured to retransmit the time-reversed signals to ensure spatial and temporal focusing; and a calibration and feedback module configured to continuously monitor channel conditions and vehicle motion via on-board sensors such as an IMU and GPS and adjust beamforming parameters in real time.

[0048] In an embodiment, the system is configured to perform the following: Signal reception and acquisition: The vehicle or roadside unit receives a distorted version of the transmitted signal due to channel-induced multipath; Time reversal: The system applies a time reversal process, effectively reversing the time characteristics of the received waveform; Phase coherent transmission: The time-reversed signal is retransmitted through the same medium, and the energy is refocused back to the original source or target receiver.

[0049] FIG. 3 illustrates three time-domain plots visualizing signals at different operational stages of an electromagnetic time-reversal beamforming system, according to one embodiment of the present disclosure.

[0050] Referring to Figure 3, the plot emulates how an autonomous vehicle would benefit from this system in a complex, multipath-heavy urban environment. The plot shown in the figure illustrates signal processing in a digital communications context, including modulation, channel effects, and detection or gain control mechanisms. A detailed explanation of the plot shown in Figure 3 is provided below.

[0051] Plot 1 shows a transmitted signal such as binary phase shift keying or quadrature phase shift keying. This plot displays a digital signal oscillating rapidly between two different amplitude levels, such as +1 and -1. This plot strongly suggests a binary phase shift keying or quadrature phase shift keying modulated signal. In binary phase shift keying, data bits are mapped to phase shifts (0 or π radians), typically represented by amplitudes of +1 and -1. In quadrature phase shift keying, upsampling and pulse shaping allow the baseband signal to also exhibit these amplitude levels. This plot represents an ideal digital signal generated by the transmitter, before distortion or noise from the communication channel occurs. The x-axis is time (seconds) and the y-axis is amplitude. The time shown is 1×10 -3 seconds (1 millisecond).

[0052] The middle plot, 2, shows the received signal before the event. In this plot, approximately 0.5×10 -3 Up until seconds, a noisy signal with a relatively high average amplitude is shown. After this point, the amplitude suddenly drops to a much lower, but still noisy, level for the remainder of the plot. This plot likely represents the received signal passing through the communications channel and being corrupted by noise. The following results can be observed in this plot:

[0053] 0.5×10 -3 Seconds ago: Higher average amplitude and visible noise suggest a signal is present and being received, but with inherent channel loss and noise.

[0054] 0.5×10 -3 Seconds later: A sudden drop in amplitude indicates a significant event or change in the communications link. This could indicate loss of signal due to blockage or severe fading, a reduction in transmitting power from the transmitter, a change in channel conditions that increases attenuation, or the transmitter being turned off or moved out of range. A sustained low-level fluctuation suggests that the desired signal has almost disappeared or is significantly weakened, but noise is still being received. Plot 3, shown in the bottom panel, shows the processed or detected signal after the event. This plot initially shows a very low amplitude signal, representing noise. However, it grows to approximately 0.5 × 10 -3 After a few seconds, there is a sudden large increase in the signal amplitude, followed by a high noise level for the remainder of the plot. This plot depicts the reverse behavior of Plot 2 at the transition point.

[0055] ≒0.5 × 10 -3 Before: The small amplitude indicates that a significant single signal was not detected or was suppressed by the processing step.

[0056] 0.5×10 -3 Seconds later: The sudden increase in amplitude correlates with the drop in plot 2, strongly suggesting a detection or activation event.

[0057] Energy detection: The system is designed to detect the presence of a signal by thresholding the energy of the signal, when the signal appears or there is a significant increase in energy after ≈0.5 × 10-3 s.

[0058] Automatic Gain Control or Power Control: In this case, the second plot represents the input to the automatic gain control circuit, and the third plot represents its output. The automatic gain control attempts to maintain constant output power. As the input signal drops (plot 2), the automatic gain control increases its gain to compensate, resulting in a higher output amplitude (plot 3), representing a typical response in a receiver to normalize signal levels.

[0059] Switching signal sources: Another strong signal source may have become active or switched on at that time.

[0060] Referring to Figure 3, a digital signal is transmitted, the received signal suddenly experiences a large drop in power or loss of signal at approximately 0.5 ms, and the receiving mechanism responds to this change by suddenly increasing the amplitude of the processed signal 0.5 ms later, either to compensate for the loss or to highlight the presence of a newly detected or amplified signal.

[0061] FIG. 4 is a plot illustrating the effects of a Rayleigh fading channel and the benefits of time-reversal beamforming, in accordance with one embodiment of the present disclosure.

[0062] Referring to Figure 4, three different plots represent the transformation of a quadrature phase shift keying modulated signal through a wireless channel, followed by the effect of time-reversal beamforming. An explanation of each plot shown in Figure 4 follows:

[0063] The top plot, representing the transmitted signal (quadrature phase shift keying), shows the absolute amplitude of the transmitted signal. This is a quadrature phase shift keying modulated signal, which, ideally, has a relatively constant envelope. After pulse shaping, the signal exhibits amplitude variations, ranging from 0.2 units to 0.7 units. This plot represents the shape of the signal as it leaves the transmitter, before it is subjected to channel impairments. The x-axis represents time in milliseconds (ms), and the y-axis represents amplitude.

[0064] The center plot shows the received signal without time reversal, showing the absolute amplitude of the signal after propagation through a simulated wireless channel containing additive white Gaussian noise. This signal has not undergone time reversal processing. The pronounced, irregular amplitude fluctuations in this plot, characterized by numerous deep fades where the signal amplitude drops to near zero and occasional peaks, are indicative of a signal traveling through a Rayleigh fading channel where multipath propagation causes destructive and constructive interference, leading to severe signal degradation and loss of received power. The presence of noise further contributes to the jagged appearance of the signal.

[0065] The bottom plot, representing the received signal after time-reversal beamforming, shows the absolute amplitude of the received signal after applying time-reversal beamforming. Comparing the bottom plot with the middle plot, we see a significant increase in the signal's peak amplitude (reaching approximately 2 units, more than twice the peak of the transmitted signal, and substantially higher than the unbeamformed received signal). The deep fades observed in the middle plot have been largely mitigated, and the signal maintains a higher, more consistent amplitude level throughout the transmission period. This plot visually confirms the effectiveness of time-reversal beamforming in coherently combining multipath components, thereby concentrating signal energy at the receiver and significantly mitigating the deleterious effects of fading and dispersion in the wireless channel. The signal is stronger and more robust, demonstrating a significant improvement in the effective signal-to-noise ratio.

[0066] In an embodiment, the system receives a multipath-distorted signal, time-reverses the received signal, dynamically estimates channel state information, determines an adaptive retransmission beamforming vector, and retransmits the reversed signal using the vector to spatially concentrate energy from the vehicle to all receivers. The system continuously optimizes retransmission parameters based on real-time vehicle mobility and environmental feedback for adaptive beamwidth, resolution, and gain. The system is configured to first record the distorted received wavefront, then apply inverse time filtering to create a time-reversed signal, then phase-coherently retransmit this time-reversed signal into the channel, and then adaptively optimize the retransmissions for sub-millisecond precision and enhanced signal-to-noise ratio at all vehicular receivers.

[0067] In one embodiment, a system includes a multi-element antenna array, a time-reversal processor for acquiring and inverting a received signal, a real-time channel estimator for dynamic channel state information, an adaptive beamforming controller for generating retransmission vectors, and a retransmission module for spatially focusing the inverted signal. The system further includes an interference mitigation module configured to suppress undesired signals by null steering and spatial filtering prior to retransmission.

[0068] The proposed electromagnetic time-reversal beamforming system offers several advantages over existing systems: robustness to multipath and non-line-of-sight conditions (time reversal enables precise spatial focusing even in highly scattering channels); low latency (sub-millisecond signal processing ensures compliance with autonomous vehicle-to-everything requirements); adaptive beam control (real-time feedback-based calibration ensures uninterrupted communication even during high-speed movement and mobility transitions); scalability to mmWave / THz bands (compatible with future high-frequency communication standards); and low computational overhead (exploiting the reciprocity of the physical channel reduces the reliance on complex matrix inversions and high-dimensional channel estimation).

[0069] Applications where the proposed system would be beneficial include real-time cooperative maneuvering and lane changes, safety messaging at urban intersections, high-throughput infotainment services while on the move, edge-assisted driving assistance in smart cities, and enhancing resilient all-round vehicles in tunnels and highways.

[0070] This invention provides a time-reversal electromagnetic beamforming system that offers an effective approach to vehicle communications, overcoming the limitations of conventional beamforming techniques in multipath environments and ensuring low-latency, highly reliable communications, essential requirements for the safe and efficient operation of autonomous vehicles.

[0071] The drawings and the foregoing description illustrate exemplary embodiments. Those skilled in the art will appreciate that one or more of the described elements may be combined into a single functional element. Alternatively, certain elements may be divided into multiple functional elements. Elements of one embodiment may be added to another embodiment. For example, the order of the steps described herein may be changed and is not limited to the aspects described herein. Furthermore, the actions in any flow diagram need not be performed in the order shown, and not all actions necessarily need to be performed. Furthermore, actions that are independent of other actions may be performed in parallel with other actions. The scope of the embodiments is in no way limited by these specific examples. Numerous variations, such as differences in structure, dimensions, and use of materials, are possible, whether or not explicitly stated herein. The scope of the embodiments is broad, as defined at least by the following claims.

[0072] Although advantages, other benefits, and solutions to problems have been described above with respect to particular embodiments, the advantages, benefits, solutions to problems, and elements that may cause or make more noticeable an advantage, benefit, or solution are not to be construed as critical, essential, or required features or elements of any or all of the claims.

Claims

1. 1. An electromagnetic time reversal beamforming system, comprising: a rigid support frame carrying spatially distributed antenna array elements, each antenna element mounted using adjustable fixtures to maintain a predefined geometric alignment and orientation, each antenna element physically connected to a modular radio frequency front end compartment; a high frequency front end compartment, the high frequency front end compartment consisting of a set of electromagnetically shielded enclosures, each containing a low noise amplifier unit connected to a coaxial signal conduit from a corresponding antenna element, each amplifier unit further hardwired to a signal digitization board including an analog-to-digital converter; a signal conditioning enclosure comprising a plurality of plug-in filter modules for analog and digital noise attenuation and a synchronization module including a timing crystal oscillator and a delay matching circuit, the plug-in filter modules being electrically connected via ribbon cables or impedance-controlled microstrips to maintain phase matching across signal lines from the plurality of antenna channels; a time-reversal processing unit, the time-reversal processing unit housed in a thermally managed chassis, the time-reversal processing unit including a wavefront acquisition module having a high-speed sample-and-hold integrated circuit and a waveform storage array; 1. An electromagnetic time-reversal beamforming system comprising: a re-radiating subsystem including a phased antenna transmitter array mounted on a connectable mechanical fixture to radiate the processed time-reversed signal toward a source of input signal distortion with high spatial and temporal coherence using physical signal routing paths and phase-calibrated antenna elements, each antenna of the phased antenna transmitter array coupled via a digitally controlled phase shifter to an impedance-matched power amplifier located on an emissions control board housed in a grounded metal casing.

2. the chassis of the time reversal processing unit comprises an active thermal management system consisting of a network of miniature heat pipe assemblies, thermoelectric coolers, and integrated temperature sensors; These components are embedded beneath the processing rack and coupled to a finned aluminum heat sink array and axial fan system attached to the chassis frame to ensure operational stability of the heat-sensitive inverting circuitry. the signal digitization board is enclosed within a grounded conductive compartment lined with ferrite-based electromagnetic interference absorbing tiles; 2. The electromagnetic time reversal beamforming system of claim 1, wherein all interconnecting conduits between the amplifier units and the analog-to-digital converters are constructed using coaxial or twisted-pair shielded cables terminated with impedance-matching connectors.

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