Passive communication system and method using reconfigurable smart surface

Abstract

Methods, systems, and apparatus are provided for passive communication with a device. The device is a communication network terminal device, or a device with practical application rather than as a network infrastructure device. In one embodiment, a reconfigurable intelligent surface (RIS) is associated with the device, and information for use in communication by the device is obtained. An electromagnetic signal from a transmitter is incident on the RIS, and the RIS reflects the electromagnetic signal to a receiver. The reflections may involve beamforming to direct the reflections to a controllable direction. The RIS is modulated to facilitate modulation of the reflection so as to carry the information of the device. This may include amplitude modulation and / or phase modulation. The transmitter and the receiver are coordinated over a channel separate from the electromagnetic signal and its reflections.

Description

Technical Field

[0001] This disclosure generally relates to wireless communication and sensing, and more particularly to reconfigurable smart surfaces for sensing of reflected signals, electromagnetic signal modulation and radar-like signals. Background Technology

[0002] Wireless communication involves a device that transmits signals via an antenna and another device that monitors those signals. In contrast, technologies such as radar and lidar can be used to detect the location of objects by transmitting electromagnetic signals and monitoring reflections from them. Furthermore, integrated sensing and communication (ISAC) technology is developing, in which signal transmitters and receivers can use communication frequencies to detect objects in a manner similar to radar or lidar applications.

[0003] A reconfigurable intelligent surface (RIS) is proposed as a controllable electromagnetic reflector for purposes such as improving communication channels between transmitters and receivers. For example, a RIS can comprise a one-dimensional or two-dimensional array of numerous tunable passive reflectors. When combined and tuned, these reflectors can induce controllable amplitude and / or phase changes in the reflection of the incident signal, thereby enabling beamforming of the reflection in a desired direction.

[0004] However, in some radar, LiDAR, and similar ISAC applications, the detected objects are passive participants and do not actively transmit information through their reflected signals. To date, RIS has not been applied in a way that addresses this issue. Furthermore, wireless communication with terminal devices can be complex and energy-intensive, as such devices typically have limited battery capacity. Even when transmitting only a small amount of information, multiple signals need to be sent and received according to potentially complex schemes, which can lead to inefficient use of terminal devices and / or spectrum resources.

[0005] Therefore, it is necessary to develop communication systems and methods to avoid or mitigate one or more limitations present in the aforementioned prior art.

[0006] The purpose of providing this background information is to disclose information that the applicant believes may be relevant to the present invention. It is neither necessary nor should it be construed as any of the foregoing information constituting prior art. Summary of the Invention

[0007] This disclosure provides a system and method for passive communication on behalf of a specific device using a reflective intelligent surface (RIS). According to this disclosure, an RIS associated with a first device (e.g., a terminal device such as a user equipment (UE)) reflects incoming electromagnetic signals in a specific manner, such that the reflection encodes information. This encoding is achieved by manipulating the RIS to alter its reflection characteristics in order to modulate the electromagnetic signals, for example, by amplitude or phase modulation. The electromagnetic signals are transmitted via this RIS reflection to retrieve the information. The encoded information may be, but is not limited to, identifiers, states, or locations. Furthermore, the RIS can be used to direct its reflections in a selected specific direction to facilitate reception. A transmitter sends signals to the RIS so that the reflections can be induced, collected, and processed to recover the encoded information. A receiver can cooperate with the transmitter to receive and process the reflections. The above operations can be performed prior to a setup phase, which includes active communication by the UE.

[0008] According to an embodiment, an apparatus is provided including a reconfigurable intelligent surface (RIS) and a controller. The apparatus may be integrated with or operatively coupled to a first device. The RIS is used to interact with incident electromagnetic signals transmitted from or by transmitters at different locations. The controller is used to operate the RIS to redirect the electromagnetic signals in a direction received by a receiver using beamforming. The receiver cooperates with the transmitter to interrogate the apparatus using the electromagnetic signals. The controller is also used to operate the RIS to simultaneously modulate the electromagnetic signals to include information to be transmitted to the receiver. The apparatus is also used to obtain the information to be transmitted to the receiver from the first device, which is co-located with the apparatus. The first device is a communication network terminal device, or a device with a practical application rather than being a network infrastructure device.

[0009] In various embodiments, the first device and the RIS can move together, and the RIS can be redirected, wherein the controller responds to the movement of the RIS and the redirection of the RIS to adjust the redirection of the electromagnetic signal. In various embodiments, the first device is a device that does not have long-range wireless transmission capabilities other than relying on the RIS. In various embodiments, the first device is a user equipment (UE) device.

[0010] In various embodiments, the information to be transmitted to the receiver includes one or more of the following: the location of the first device, the identifier of the first device, the distress signal of the first device, and the status of the first device.

[0011] In various embodiments, the controller is also configured to perform the following operations on each of a plurality of incident signals. Each incident signal corresponds to one of a plurality of different time intervals. The controller reconfigures (e.g., during each of the plurality of different time intervals) the RIS to redirect the incident signal in a different corresponding direction of the scan mode. The controller is also configured (e.g., during each of the plurality of different time intervals) to operate the RIS to simultaneously modulate the incident signal to include the information to be transmitted to the receiver. Hereinafter, one of the incident signals represents the electromagnetic signal. In some embodiments, the scan mode is configured based on previously acquired information indicating a range of directions, which includes the direction received by the receiver. In some embodiments, the scan mode is also configured based on the spatial orientation perceived by the RIS.

[0012] In various embodiments, the transmitter and the receiver are co-located in a single-base configuration. In other embodiments, the transmitter and the receiver are located in different positions in a dual-base configuration.

[0013] In various embodiments, the electromagnetic signal is a sensing signal generated, transmitted, and received according to radar or integrated sensing and communication (ISAC) operation. In various embodiments, the electromagnetic signal may be characterized as an interrogation signal for obtaining information about the first device.

[0014] In various embodiments, the transmitter and the receiver coordinate with each other via a first communication channel or an internal link, and the electromagnetic signal is transmitted and received via a second communication channel separate from the first communication channel. If the transmitter and the receiver are co-located or integrated, the internal link (e.g., internal electronics carrying the signal) can be used, which facilitates coordination between the transmitter and the receiver.

[0015] In various embodiments, the direction received by the receiver is a direction known to the controller. The direction can be known based on one or more of the following: the spatial orientation perceived by the RIS; information previously acquired during the setup phase.

[0016] In various embodiments, the first device is configured to interact wirelessly with the transmitter, or a second device associated with the transmitter and / or the receiver, during a setup phase. In these embodiments, the first device is also configured to configure the controller to operate the RIS based on information acquired during the setup phase.

[0017] In some other embodiments, the information acquired during the setup phase includes one or more of the following: the location of the transmitter, the location of the receiver, the location of the device, the location of the first device; the format of the information to be transmitted to the receiver; an indication of the modulation and coding scheme to be used by the device when modulating the electromagnetic signal; an indication of the operating timing of the RIS; and an indication of the scanning mode to be implemented by the device for redirecting the electromagnetic signal in different directions.

[0018] In some embodiments, the interactions during the setup phase include beam training interactions for configuring the operation of the transmitter and / or the receiver.

[0019] In various embodiments, the RIS is mounted to the first device. In various embodiments, the RIS is operatively coupled to the first device via a short-range wireless communication link.

[0020] In various embodiments, the controller is configured to initiate operation of the RIS in response to a trigger from the first device.

[0021] In various embodiments, modulating the electromagnetic signal includes phase modulation and / or amplitude modulation.

[0022] In various embodiments, the transmitter and the receiver further cooperate to locate the device by guiding the electromagnetic signal and processing the reflection of the electromagnetic signal from the RIS.

[0023] According to an embodiment of the present invention, a system is provided, including the apparatus as described above, and a first device co-located with the apparatus.

[0024] According to embodiments of the present invention, a second apparatus is provided, comprising a transmitter and a receiver, for example, as part of one or more base stations. For example, the transmitter, which may be part of the apparatus or system described above, is used to transmit electromagnetic signals to a reconfigurable intelligent surface (RIS). The receiver cooperates with the transmitter to use the electromagnetic signals to interrogate a first device associated with the RIS. The receiver is used to monitor and receive reflections of the electromagnetic signals from the RIS. The apparatus is also used to process the reflections to recover information already included in the reflections by the RIS modulating the electromagnetic signals.

[0025] The second device may include, in various embodiments, the various details and features described above with respect to the device including the RIS and the controller. These details and features will not be repeated here. However, further details and features present in at least some embodiments of the second device are described below.

[0026] In various embodiments, the transmitter and the receiver cooperate with each other via a first communication channel or internal link to interrogate the first device, and the electromagnetic signal is transmitted and received via a second communication channel separate from the first communication channel (and internal link).

[0027] In various embodiments, the receiver reports the information to the transmitter or another device controlling the transmitter after recovering the information.

[0028] In various embodiments, the transmitter is configured to sequentially transmit the electromagnetic signals in each of a plurality of different directions according to a scanning pattern. The scanning pattern may be based on previously acquired information indicating a range of directions, including directions toward the RIS.

[0029] In various embodiments, the second device is configured to interact with the first device wirelessly during a setup phase. In such embodiments, the device is further configured to self-configure, based on information acquired during the setup phase, to perform operations such as transmitting the electromagnetic signal, monitoring the reflection, processing the reflection, or a combination of the above operations.

[0030] The information acquired during the setup phase may include one or more of the following: the location of the RIS, the location of the first device; the format of the information to be transmitted to the receiver; an indication of the modulation coding scheme to be used by the RIS when modulating the electromagnetic signal; an indication of the operating timing of the RIS; and an indication of the scanning mode to be implemented by the RIS for redirecting the electromagnetic signal in different directions.

[0031] The interaction during the setup phase may include receiving one or more of the following at the second device: an indication that the RIS is capable of redirecting and modulating the electromagnetic signal; the location of the RIS; configuration information of the RIS or the first device; the format of the information to be transmitted to the receiver; an indication of how to use the RIS to interpret a specified instance of the information to be transmitted to the receiver; an indication of the modulation coding scheme to be used by the RIS when modulating the electromagnetic signal; an indication of the operating timing of the RIS; and an indication of the scanning mode to be implemented by the RIS for redirecting the electromagnetic signal in different directions.

[0032] In various embodiments, the second device is also configured to interact wirelessly with the first device associated with the RIS during a setup phase to initialize parameters that can be used to transmit the electromagnetic signals and / or process the reflections.

[0033] According to an embodiment, a method is provided associated with a first device from which information is to be obtained. The method is performed by a device, such as a controller. The method includes obtaining information to be transmitted to a receiver from the first device, which is co-located with the device. The first device is a communication network terminal device, or a device having an actual application rather than serving as network infrastructure equipment. The method includes operating a reconfigurable intelligent surface (RIS) to interact with an incident electromagnetic signal transmitted by a transmitter. The interaction includes redirecting the electromagnetic signal in a direction received by the receiver using beamforming. The receiver cooperates with the transmitter to interrogate the device using the electromagnetic signal. The interaction includes simultaneously modulating the electromagnetic signal to include the information to be transmitted to the receiver.

[0034] According to an embodiment, a method associated with an apparatus for obtaining information from a first device is provided. The method includes: transmitting an electromagnetic signal to a reconfigurable intelligent surface (RIS) via a transmitter. The method includes: interrogating the first device associated with the RIS using the electromagnetic signal via a receiver cooperating with the transmitter, the receiver being configured to monitor and receive reflections of the electromagnetic signal from the RIS. The method includes processing (using processing electronics) the reflections to recover information therefrom, the information being included in the reflections by modulating the electromagnetic signal through the RIS. The information included in the reflections may be provided from the first device associated with the RIS, the first device being: a communication network terminal device, or a device having a practical application rather than being a network infrastructure device.

[0035] Other aspects of the above method may also be provided, for example, in accordance with the foregoing embodiments of the corresponding apparatus already described above.

[0036] According to an example, an electronic device in a communication network is provided, the device including a processor, a network interface, and a memory, and for performing one or more methods described herein. According to an example, a system composed of such electronic devices is provided, these devices being interconnected and used to work collaboratively to perform one or more methods described herein.

[0037] According to an example of the invention, a computer program product is provided, comprising (e.g., a non-transitory) computer-readable medium storing statements and instructions that, when executed by one or more computer processors, cause the computer processors to perform the methods described above. The computer processor may be part of one or more electronic devices (e.g., network entities) as described herein.

[0038] The foregoing has described embodiments and examples in conjunction with various aspects of the present invention, and these embodiments and examples can be implemented based on these aspects. Those skilled in the art will understand that embodiments can be implemented in conjunction with the aspects described therein, but also in conjunction with other embodiments of that aspect. It will be apparent to those skilled in the art that embodiments are mutually exclusive or contradictory. Some embodiments may be described in conjunction with one aspect, but may also be applicable to other aspects, as will be apparent to those skilled in the art. Attached Figure Description

[0039] Other features and advantages of this disclosure will become apparent from the following detailed embodiments, taken in conjunction with the accompanying drawings, in which:

[0040] Figure 1 A reconfigurable intelligent surface (RIS) according to an embodiment of the present disclosure is shown.

[0041] Figure 2 An apparatus according to an embodiment of the present disclosure is shown, including a transmitter, a receiver, a RIS, a controller, and a first device associated with the RIS;

[0042] Figure 3 A transmitter and receiver integrated into a single base station according to an illustrative embodiment of the present disclosure are shown, as well as user equipment (UE) associated with a RIS that modulates the reflection of electromagnetic signals in a monobase arrangement.

[0043] Figure 4The scanning / frequency sweeping operation of the transmitter and RIS according to embodiments of the present disclosure is illustrated;

[0044] Figure 5 The interaction between a first device and a base station (or other network device) according to an embodiment of the present disclosure is illustrated;

[0045] Figure 6 A transmitter of a RIS (Resonance Information System) interrogating a UE and a receiver located at different positions are shown in a dual-base arrangement according to an embodiment of the present disclosure, wherein the RIS modulates an electromagnetic signal from the transmitter and is received by the receiver;

[0046] Figure 7 A single-base arrangement with an additional intermediate RIS is shown according to an embodiment of the present disclosure;

[0047] Figure 8 A dual-base arrangement with an additional intermediate RIS is shown according to an embodiment of the present disclosure;

[0048] Figure 9 An electronic device that can be used to perform operations according to an embodiment of the present disclosure is shown.

[0049] It should be noted that in all the accompanying drawings, similar features are identified by similar reference numerals. Detailed Implementation

[0050] RIS (Radio Reflector Array) is an enabling technology for the engineered control of radio signal propagation in wireless networks. By appropriately tuning signal reflection using a large number of low-cost passive reflector elements, RIS can dynamically alter the wireless channel to enhance communication performance. Generally, an RIS can be a planar surface comprising a large number of passive reflector elements, each of which can independently and simultaneously exert controllable variations on the amplitude and / or phase of the incident signal. This control allows the reflection to be beamformed into a controllable direction. Multiple RIS surfaces can be combined to form an RIS structure, creating a 3D shape. Figure 1 A RIS 110 is shown, comprising a set of passive reflective units 115 operated by a controller 120. In one possible use case, a transmitter 127 transmits one or more signals 125 arriving at the RIS 110. The RIS 110 controllably (via beamforming) redirects some or all of the signals 125 to a first beam 130 toward a first user 132, and also redirects some or all of the signals 125 to a second beam 135 toward a second user 137. The RIS units can be controlled according to their phase response and / or on / off conditions (for amplitude control). As will be readily understood by those skilled in the art, the RIS surface can be reconfigured in a variety of ways.

[0051] RIS technology was initially proposed as an auxiliary means to enable attractive features that could provide performance gains for 6G wireless mobile networks. Such features include (but are not limited to): (i) extending coverage by creating virtual line-of-sight (LoS) links to bypass obstacles between transceivers via intelligent reflection; (ii) improving channel power and rank by adding more controllable signal paths between transceivers in multi-antenna communication scenarios; (iii) mitigating interference by effectively suppressing co-channel interference; (iv) enhancing connection density by adding additional signal paths in desired directions; (v) achieving ultra-high reliability through refined channel statistics / distribution, such as converting Rayleigh / fast fading channels to Rice / slow fading; and (vi) improving positioning accuracy by providing controlled signal reflections and serving as reference nodes for local awareness.

[0052] In this regard, a typical RIS surface is deployed at an intermediate location between the end device (UE) and the base station, and is used to reflect signals sent by the UE to the base station for reception and / or reflect signals sent by the base station to the UE for reception. In fact, according to the literature, RIS are generally considered to be mounted on the walls of large, fixed structures (such as buildings), as well as on street banners. This deployment is very convenient for the applications mentioned above. In this paradigm, the RIS location is fixed, which makes configuring its units easy so that reflections can be controlled and directed.

[0053] In contrast, according to embodiments of this disclosure, the RIS surface is deployed at a potential mobile device that is not part of the network infrastructure. For example, the RIS may be co-located with a device that may or may not have its own (active) wireless transmitter and receiver. This device may be a communication network terminal device, such as a UE. The deployed RIS surface is operated to modulate electromagnetic signals incident on the RIS surface, thereby carrying information. Modulation in the signal can be achieved by corresponding modulation of the properties of the RIS surface, causing a change in the RIS's reflection of the electromagnetic signal. This allows information to be wirelessly transmitted from the associated device via passive reflection. For clarity, a terminal device is generally considered as a device within a communication network that requires support from the communication network, rather than being part of the communication network infrastructure. The device associated with the RIS may be a terminal device or other device (excluding network infrastructure devices).

[0054] Furthermore, in a possible radar, LiDAR, or ISAC object sensing scenario, the object being sensed is a passive participant. Therefore, the reflection of electromagnetic signals may scatter in multiple directions, resulting in a reduced number of reflected signals that can be used for sensing purposes. In contrast, according to at least some embodiments, the RIS can be operated to direct electromagnetic signals in a specific direction that allows for a sufficiently high signal strength at the receiver (e.g., directly towards a line-of-sight receiver). This can be achieved through the known orientation and direction of the transmitter, receiver, and RIS, or by adjusting the RIS over time to sequentially scan a series of directions with the reflected signals, or a combination of both. This has the potential to improve electromagnetic signal gain. This method can be used simultaneously and in combination with the aforementioned modulation of electromagnetic signals.

[0055] Embodiments of this disclosure can improve the power efficiency of devices requiring communication, such as, but not limited to, 6G and higher-level UEs, which have limited access to power. For this purpose, passive communication utilizing RIS reflection of electromagnetic signals is used. This facilitates basic processes such as UE detection and low-rate message transmission and reception. Embodiments can be integrated with other integrated sensing and communication (ISAC) technologies as part of future mobile networks. ISAC technology allows for dual functionality at the base station (BS). Under ISAC, waves emitted by the BS can be used to carry information via mobile broadband methods, and these waves can also be used for object sensing in a radar-like manner. In this architecture, when a signal emitted by the BS encounters an object, a portion of it is reflected. ISAC proposes that object sensing can be achieved by monitoring and processing these reflections.

[0056] Sensing plays an increasingly important role in 6G wireless networks, especially in emerging applications such as smart transportation, smart homes, smart cities, and various location-based services. With the widespread adoption of massive MIMO technology and the development of wireless communication systems towards higher frequency bands such as millimeter waves and terahertz, sensing and communication systems are becoming increasingly similar in terms of system architecture, channel characteristics, and signal processing methods. This has led to the use of the same equipment and / or waveforms for communication and sensing, and has driven the concept of integrating sensing and communication into the same business unit (BS) within the ISAC (Interactive Space Communication) technology framework.

[0057] Embodiments of this disclosure can be used to beneficially guide reflections by configuring the RIS, thereby improving this sensing. Embodiments of this disclosure can be used, alone or in association with this sensing, to transmit information from a device by modulating electromagnetic signals (e.g., ISAC sensing signals).

[0058] In some embodiments, electromagnetic signals are transmitted primarily for the purpose of obtaining information about a first device, through reflection and modulation by the RIS. In such embodiments, and for this reason, the electromagnetic signal may be referred to as, for example, an "interrogation signal." An interrogation signal is a signal transmitted primarily for the purpose of reflection from the RIS, which modulates the interrogation signal (more specifically, its reflection) as described herein, such that the reflection can be received at a receiver cooperating with the transmitter (e.g., via a separate channel or by integrating with the transmitter). Interrogations can also be transmitted via radar-like or ISAC operations to achieve the additional purpose of locating the RIS or the first device associated therewith; thus, the interrogation signal may be a sensing signal generated, transmitted, and received according to ISAC or radar operations. The transmitter and receiver may further cooperate to locate the RIS (and its co-located devices) by guiding the interrogation signal and processing its reflection, following typical ISAC or radar procedures. Moreover, in some embodiments, the RIS may use its beamforming capabilities to enhance the gain of the interrogation signal for (at least) device location purposes, and to embed information within the interrogation signal.

[0059] In various embodiments, and in light of the foregoing, the electromagnetic signals transmitted prior to RIS modulation carry virtually no information. Therefore, the electromagnetic signals function solely as a medium for transmitting information from the RIS to the receiver. In some embodiments, the electromagnetic signals may be transmitted with specific information intended solely for managing device queries. For example, this information may include an indicator of the time the electromagnetic signal was transmitted, a tracking tag for the electromagnetic signal, an indicator of the direction the electromagnetic signal was transmitted, etc. In some embodiments, this information, which may be present on the electromagnetic signals, is intended for decoding by the receiver. In other embodiments, such information may exist for a first device co-located with the RIS. This situation may arise when the transmitter is unaware of whether the first device is still using active communication or has switched to passive communication to conserve energy. It may also arise when the first device may still have the power required to receive signals but wishes to conserve energy during transmission. It should be noted that in some RIS implementations, the RIS itself may be provided with some active units with limited receiving capabilities, in which case the RIS may be able to receive signals and decode information.

[0060] As described above, UEs or other terminal devices participating in active communication expect to actively send messages to BSs, and such active transmission consumes power. In contrast, according to embodiments of this disclosure, UEs or other devices can use RIS reflection to perform or benefit from some basic processes, which are passive (transmissions that do not generate new RF energy) and require far less power. Configuring RIS not only consumes less power than actively transmitting signals via antenna, but UEs or other devices also do not need to perform related activities such as four-way handshakes, random access channel usage, monitoring shared channels to coordinate medium access, collision resolution, etc. In some embodiments, the power load generated by the communication and data transmission processes disclosed in this invention is primarily transmitted to the transmitter and away from the first device.

[0061] Therefore, this embodiment provides a method for passive-like (reflection-based) communication. Electromagnetic waves (electromagnetic signals) can be transmitted by a transmitter such that they are incident on a RIS (Receptor Array of Independent Components) typically co-located (e.g., close to) with a terminal device (such as a UE) or other type of (non-network infrastructure) equipment. An associated receiver, co-located with or located separately from the transmitter, monitors the reflection of the electromagnetic waves (electromagnetic signals). The transmitter and receiver can be associated with the same base station (BS). For clarity, the electromagnetic signal propagating from the transmitter to the RIS can be considered as the incident electromagnetic signal, while the electromagnetic signal propagating from the RIS to the receiver can be considered as a redirected or reflected electromagnetic signal.

[0062] The receiver can then perform signal processing and extract useful information from the reflection. This signal processing may include determining the location information of the RIS, for example, using possible radar system techniques. The signal processing may additionally or alternatively include recovering information encoded into the reflected electromagnetic signal due to the corresponding modulation of the RIS's reflection characteristics, and thus modulating the reflection.

[0063] Embodiments of this disclosure can use a RIS to improve reliability and achieve communication from the RIS to the receiver through this modulation of the RIS's reflection characteristics. The RIS can guide reflections to improve reliability and signal gain, while also using passive reflection devices to communicate with the receiver.

[0064] According to embodiments, the UE may be equipped with (or connected to) a (e.g., miniature) RIS, onto which (e.g., beamformed) electromagnetic (e.g., microwave frequency) signals may be irradiated. Other devices (including other terminal devices) may be equipped with or connected to the RIS in a similar manner. Such devices may be devices with practical applications rather than as network infrastructure devices. Devices equipped with or supporting the RIS may include, but are not limited to, keys, backpacks, clothing, consumer electronics, consumer products, traffic lights, and vehicles (cars, bicycles, scooters, etc.). Devices may be manned or autonomously operated air or ground vehicles. Devices may be medical devices located inside or outside the human body. Devices may also be those that are difficult to continuously provide high levels of power, such as those powered by battery replacement. Devices may be one of a variety of types of devices that may be mobile and can be operatively coupled, mounted, integrated, or attached to the RIS, controller, and battery (or other power source). It should be noted that in some embodiments, the device coupled to the RIS may be a device that does not have long-range wireless transmission capabilities other than relying on the RIS itself. That is, the RIS may be the primary means of communication for such devices. In this case, configuration may need to be performed before device deployment.

[0065] Due to low power requirements, energy harvesting technologies that generate electricity from solar, wind, vibration, water flow, or other sources may be potentially used to power controllers and RIS (Radio Retrieval System) directly or via batteries, capacitors, or other energy storage devices. The RIS can be installed in the device or connected via short-range wired or wireless (e.g., Wi-Fi) connections. ™ or Bluetooth ™ (or optical communication links can be operatively coupled to the device.)

[0066] For more details, please see Figure 2A device comprising a RIS 215 and a controller 220 may be provided. This device is operatively coupled to a first device 210, such as a UE, or another communication network terminal device, or another device having a practical application rather than being a network infrastructure device. The RIS 215 interacts with an incident electromagnetic signal 235 transmitted by a transmitter 230A. The transmitter 230A may or may not be part of a base station. The RIS 215 reflects (redirects) the electromagnetic signal 235 while also performing beamforming to controllably redirect the reflection. The RIS 215 operates in response to a command signal from the controller. Using beamforming, the RIS 215 redirects the electromagnetic signal in the direction received by the receiver 230B. Thus, a reflection 240 of the electromagnetic signal is transmitted between the RIS 215 and the receiver 230B. This beamforming can be based on reflection beamforming, as will be readily understood by those skilled in the art. The direction for receiving may be the direction of the receiver 230B, or the direction of another RIS reflecting to the receiver, or more generally, a direction associated with providing a sufficiently high signal gain at the receiver.

[0067] During beamforming, the RIS 215 simultaneously modulates the electromagnetic signal to add specific information to the reflection 240 of the electromagnetic signal for transmission to the receiver 230B. This information is acquired by the device from a co-located first device, for example, via a wired or short-range wireless link, or through pre-configuration. Modulation may involve reconfiguring the RIS unit over time so that the phase and / or amplitude of the reflection (of the electromagnetic signal) varies with time. For electromagnetic signals with longer lifetimes (either continuous in time or in multiple independent segments), time-varying modulation can be used to embed a corresponding amount of information in the reflection. The receiver of the reflection can then recover the information through appropriate signal processing, including demodulation, decoding, etc.

[0068] Receiver 230B cooperates with transmitter 230A to acquire information from the device and thereby from its associated equipment using electromagnetic signals. Receiver 230B and transmitter 230A can thus communicate, for example, causing the receiver to provide recovered information to the transmitter or another control entity. This communication can be achieved via channel 232. In some embodiments, transmitter 230A and receiver 230B can be coordinated via a coordinating network entity 230C, which may co-locate with the transmitter and / or receiver, or be located elsewhere in the communication network infrastructure. This coordination is conducted via a channel other than any channel through which electromagnetic signals and their reflections are wirelessly transmitted to or from the RIS.

[0069] For example, transmitter 230A may transmit electromagnetic signals in different directions according to a scanning pattern in multiple instances 235, 235A. RIS 215 may reflect (reflected) electromagnetic signals in, for example, different directions according to a scanning pattern in multiple instances 240, 240A.

[0070] In some embodiments, a system is provided that includes the means as described above and a co-located first device as described above. The means and the first device may be integrated together or may be separate but operatively coupled together.

[0071] By utilizing beamforming technology, currently considered an inherent feature of mobile network operation, and combining it with ISAC technology, a BS can be transformed into a directional radar node. Furthermore, by installing or connecting a RIS (Reflection Array) on equipment such as a UE (User Equipment), the quality of reflections can be improved through the beamforming process. This helps improve the directionality toward the receiver, thereby increasing the success rate of reflection reception and decoding.

[0072] MIMO beamforming systems (BSs) are typically used as transmitters and / or receivers. MIMO antennas are used to beamform signals to a specific target and listen for reflections. The reflections are then used to extract useful information, much like in a typical radar system. However, due to beamforming characteristics, the transmitted signal can be directed towards the target, increasing the probability of actual target contact. Furthermore, with proper beamforming, reflections can be manipulated to avoid potential interference. Additionally, the ability of a BS to operate over a wide bandwidth allows the beam to assume different parameters that can be adjusted to match the reflection coefficient of the target object. When the exact location of the target is unknown, the BS can sweep its beam to cover the space where the target is believed to be present. Otherwise, the BS might simply sweep the entire angular domain.

[0073] Therefore, by combining beamforming and ISAC, a radar-like directional system can be designed. However, for target sensing, although the incident wave is directional, the reflection remains random and non-directional. As described in this paper, using a RIS surface at the target location can potentially improve this situation because the reflection can be directed towards the receiver. This can increase the signal strength (of the reflected electromagnetic signal) at the receiver. More specifically, RIS can improve the directivity of the reflection and enhance the overall performance of passive communication systems.

[0074] Figure 3An exemplary embodiment of this disclosure is shown, wherein the UE 210 is equipped with a RIS 215. The UE can be replaced with other types of devices. The RIS is operated by a programmable controller 220, and the RIS and controller consume relatively little power. This power consumption allows the RIS to continue operating as described above even when the UE has almost no remaining battery power. For example, the RIS can be operated using a small backup battery. Therefore, by utilizing the implicit characteristics of RIS technology, the RIS 215 can be used to reflect incident electromagnetic signals (electromagnetic waves) in an engineered manner, such that the reflection carries information such as a pre-agreed unique code or identifier. In the currently shown embodiment, the base station 230 transmits an electromagnetic signal 235, and the RIS 215 reflects the electromagnetic signal back to the base station 230 as a reflected signal 240. Through modulation by the RIS 215, the reflected signal is modulated to carry information back to the base station. The controller 220 can be integrated with the UE or the RIS, or separate from both.

[0075] More specifically, the inherent structural design and engineered tuning of the RIS allow for the configuration of RIS cells to create a phase gradient along the RIS surface. This phase gradient allows the incident signal to be redirected in a specific direction, corresponding to beamforming operations. The RIS can also add a global phase shift to all cells, which only shifts the signal phase at the receiver but does not change the direction of the reflected signal. RIS operating in this way can perform phase modulation. Using this global phase modulation, low data rate information can be embedded into the reflected signal. Furthermore, the RIS cells play a role in the beamforming power of the reflected signal. By turning a certain number of RIS cells on or off, the power or amount of the reflected signal can be manipulated. This operation can be used for amplitude modulation of the reflected signal, for example, by changing the number of RIS cells on or off over time. By combining these two capabilities, the RIS can modulate the incident electromagnetic signal using amplitude modulation and / or phase modulation, and can also reflect the incident electromagnetic signal in a controllable direction. It has been determined that a RIS with a sufficient number of cells has sufficient configurability and controllability to perform beamforming and modulation simultaneously.

[0076] Modulation can involve changing the phase and amplitude of the reflection over time, similar to how phase or amplitude modulation schemes encode information by modulating the transmitted waveform. For example, a RIS can apply a phase shift according to a first mode at a first time to encode binary zero, and a phase shift according to a second mode at a second time to encode binary one. The phase shift can vary over time to encode a sequence of binary values, and this encoding is embedded in the reflection of the electromagnetic signal incident on the RIS for a sufficiently long duration. Similarly, the RIS can apply a time-varying amplitude variation in the reflection of the electromagnetic signal by changing the number of RIS units that are active over time. For example, at a first time, all RIS units can be active, thereby amplifying the signal strength in the reflection to encode binary one. At a second time, perhaps only far fewer than all RIS units can be active, thereby weakening the signal strength in the reflection to encode binary zero. Channel coding can be used to improve the signal-to-noise ratio of the information embedded in the electromagnetic signal by the RIS.

[0077] According to embodiments, various potentially arbitrary information can be encoded into the reflection of electromagnetic signals. For example, such information may include identifiers of the UE or other devices, distress signals (SOS), status indicators, useful operational information, location information (e.g., device location), or combinations thereof. This information can be obtained from the device during configuration or on demand.

[0078] In a simple model scenario, the BS or transmitter sends electromagnetic signals to a (e.g., a miniature) RIS that is mounted or operatively coupled to a device such as the UE. The RIS is used to reflect the incident electromagnetic signal modulated in a specific (e.g., pre-agreed) pattern to embed information such as an SOS message. With the gain and improved directivity that the RIS can provide, the reflected signal is expected to have better quality at the receiver (e.g., at the BS), and the reflection can then be decoded to recover the embedded information.

[0079] An embodiment provides an apparatus (e.g., a BS) having a transmitter and a receiver, which may be co-located or located in different places. The transmitter is used to send electromagnetic signals to a RIS associated with the device. The receiver cooperates with the transmitter to query the device associated with the RIS through interaction with the RIS. Cooperation may be achieved at least in part through interaction occurring using another communication channel, or through an internal link resulting from the co-location and integration of the transmitter and receiver. Specifically, the RIS modulates and reflects electromagnetic signals as described elsewhere herein. The apparatus (e.g., the receiver) is used to process the reflections from the RIS to recover information from them. Cooperation may include the receiver reporting to the transmitter (or another device controlling the transmitter and / or receiver) after recovering information from the received reflected electromagnetic signals.

[0080] Similar to the BS side, when the device, RIS, or RIS controller does not know the exact location of the BS (or receiver), the RIS can be used to scan one or more beams to increase the probability that at least one reflection is directed towards the BS. In the absence of any BS location information, the RIS can be used to sweep the entire angular space. In other words, when the receiver's location is unknown or not precisely known, the RIS can be adjusted so that the incident electromagnetic signal will be reflected in different directions at different times. Therefore, the reflections will be scanned or swept across various angles to increase the signal strength at the receiver from which one of these reflections reaches.

[0081] Therefore, the device can be equipped with or operatively coupled to (e.g., a miniature) RIS. The RIS can be used to enable passive reflection of incident electromagnetic signals to be beamshaped and modulated in an engineered manner. The RIS can be configured to modulate the electromagnetic signals according to a specific, pre-agreed encoding format that can be understood by the receiver and converted into an understandable message. In some embodiments, the RIS can be configured on a per-application basis (e.g., via a BS) such that the reflection can be beamshaped to improve reception and decoding at the receiver (e.g., the BS). Thus, passive communication can be enabled for low-rate messaging applications.

[0082] To facilitate passive communication from a device to a base station or other receiver using RIS modulation of incident electromagnetic signals, embodiments of this disclosure may incorporate one or more of the following features. First, the device (e.g., UE) is operatively coupled to a co-located RIS. If the device is mobile, the RIS moves with the device. That is, the device and the RIS move together. Furthermore, the RIS may be (e.g., along with the device) reorientable. In such embodiments, a controller adjusts the RIS operation to redirect electromagnetic signals in response to changes in the RIS's location and possible reorientation. For example, the controller may access the RIS's location sensors (e.g., GPS) and / or orientation sensors (e.g., a gyroscope) and may adjust the angle of the RIS's reflected signals based on the sensed location and / or orientation. The controller may sense the spatial orientation of the RIS and, at least in part based on that spatial orientation, control the RIS to redirect electromagnetic signals using beamforming in a specific direction known to the controller. The controller may additionally or alternatively control the RIS to redirect electromagnetic signals in a specific direction (using beamforming) based on other information, such as that acquired during a setup phase. For example, this information may indicate the location of the receiver or a direction associated with high signal strength at the receiver.

[0083] In some embodiments, the RIS is mounted to or integrated into a device. For example, the back or casing of a mobile phone may cover the RIS's configurable reflective unit, or the RIS may be integrated into a bicycle or other vehicle. In some embodiments, the RIS uses a wired connection such as USB-C or Bluetooth. ™ A separate device is wirelessly coupled to the RIS. For example, a device (e.g., as a UE) can notify the network (e.g., a BS) of the presence of a RIS via UE capability signaling. This signaling can be sent via radio transmission during the setup phase before passive communication begins. Because the RIS and the device are co-located, the device can configure the RIS or update its configuration as needed. The locations of the RIS or the device can be considered equivalent and interchangeable herein.

[0084] Figure 4 The scanning (also known as frequency sweeping) behavior of a transmitter and a RIS according to embodiments of this disclosure is illustrated. For ease of description, the transmitter is associated with a base station, and the RIS is associated with a UE. To initiate passive communication, the BS 230 transmits beams 435 of one or more electromagnetic signals such that at least one beam is directed at the RIS 215. Different beams 435 may be transmitted simultaneously or at different times, or a combination of both. When the BS knows the location of the RIS (or the location of the UE, since they are co-located), the BS may send beams to that location for possible reflections. When the location is uncertain, the BS may send more than one beam to an area where a UE / RIS may be present. In the worst case, the BS may sweep the beams of an entire sector / area. The BS frequency sweep may depend on several factors, including, but not limited to, the previous UE location, UE type (e.g., pedestrian, bicycle, or car), and environment type (e.g., city or forest). More generally, the transmitter (e.g., the BS) may sequentially transmit different instances (or copies) of electromagnetic signals in each of several different directions according to a scanning pattern. The scanning pattern may be based on previously acquired information, such as information acquired during the setup phase. The information can indicate the directional range of the scan (frequency sweep). The directional range should include the direction toward the RIS (i.e., the line-of-sight direction or the direction in which the electromagnetic signal will have a sufficiently high signal strength when it reaches the RIS after one or more reflections).

[0085] For the RIS 215, there are two configurations that specify beam reflection characteristics. The first configuration, also known as a sweep configuration, enables the RIS to reflect the incident beam directionally. The second configuration involves the modulation of the RIS to transmit information via reflection. For the first configuration, the reflection direction is the direction that facilitates receiver reception. This can be a line-of-sight direction toward the receiver, a direction redirected to another infrastructure RIS or other reflective surface of the receiver, or another direction related to ensuring a sufficiently high signal strength at the receiver (e.g., due to favorable ambient reflection, constructed multipath interference, etc.). When the location of the receiver or the desired reflection direction is uncertain, the RIS can be used to sweep the configured directional range. In the worst case, the RIS may sweep the entire angular space.

[0086] Information regarding the frequency sweep configuration can be obtained in more than one way. In one embodiment, the frequency sweep configuration information is obtained by configuring the RIS to reflect transmitted electromagnetic signals (beams) to a set of directions by a device (e.g., a UE) or controller. The transmitter (e.g., an associated BS) informs the device or controller of the direction index (or multiple indices) corresponding to a favorable SNR. The UE, device, or controller can then use its internal sensors to adapt to changes in the RIS orientation; for example, using a gyroscope. In another scenario, the transmitter (e.g., the BS) can transmit the location of the receiver to the UE, device, or controller, and the UE, device, or controller can use its sensors (e.g., GPS and a gyroscope) to obtain the direction of the reflection. Since the RIS can sweep in multiple directions, the configuration can also include information associated with the time of each beam.

[0087] The second type of RIS configuration, also known as modulation or message configuration, allows RIS to modulate its units to add amplitude and / or phase modulation for transmitting information via reflected beams. The modulation configuration can set the number of possible phases and / or amplitudes, as well as the modulation frequency. The configuration can also include application-specific messages. In one example, the BS can configure the UE, device, or controller using an ID to identify the UE or device. In another example, the BS can configure a special set of bits for the UE, device, or controller that can be transmitted when a specific event occurs (via RIS modulation); for example, SOS. In a third example, the BS can configure the UE, device, or controller to transmit its GPS coordinates when assistance is needed (via RIS modulation). Information transmitted by or on behalf of the UE can be shared between more than one transmit and receive point (TRP) to ensure smooth operation after handover.

[0088] As instructed by the controller, scanning (frequency sweep) and modulation can work together as follows. During each of several distinct (e.g., consecutive) time intervals, the RIS is reconfigured to redirect the incident electromagnetic signal (if present) in a different corresponding direction of the scanning mode. The scanning mode can be set based on partial information about the receiver's location, or similar information. Accordingly, the scanning mode can be configured based on previously acquired information indicating a range of directions (possibly) including the receiver's location, or a transmission direction that enables good reception by the receiver. Similarly, the scanning mode can be configured based on the spatial orientation perceived by the RIS, so as to scan, for example, towards such a range of directions. It should be noted that the RIS and the controller do not detect the electromagnetic signal, therefore the reconfiguration of the RIS is performed blindly. Meanwhile, during each of these time intervals, the RIS is operated to modulate the incident electromagnetic signal (if present) to include specific information as described elsewhere herein. Thus, if and when an instance of the electromagnetic signal is incident on the RIS, it is reflected (by beamforming) to one of the scanning directions and is also modulated. As time changes, with multiple instances (or copies) of the (repeating) electromagnetic signal being sent, multiple such instances are expected to arrive at the RIS, and these instances will be reflected in different directions via modulation. At least one of these reflections is expected to be received at the receiver with sufficient signal strength for decoding. Similarly, the RIS can perform the aforementioned redirection and modulation operations on a per-event signal basis rather than on a per-time interval basis.

[0089] It may be desirable to configure the scanning modes of the transmitter and RIS to be significantly different from each other. Otherwise, it is possible to encounter a situation where the RIS is in the same part of its scan cycle each time an electromagnetic signal arrives, and this part of the scan cycle is unfavorable for the receiver to receive the reflection. Therefore, for example, one or both of the scanning modes of the transmitter and RIS can be randomized. Appropriate configuration can be performed during the setup phase. Another example is that the transmitter and RIS have different scan frequencies. In one embodiment, the transmitter frequency will be much slower than the RIS frequency, so the RIS can reflect the same transmitter signal in different directions. In another embodiment, the transmitter frequency is much higher than the RIS frequency, in which case the RIS will reflect over long intervals to ensure that the transmitted signal is reflected in a specific direction. The different modes may depend on the RIS capability; for example, the RIS phase transition frequency. In another embodiment, the size of the scan beam can be different (wider and / or narrower). In yet another embodiment, the scanning can be progressive, i.e., starting with a wide beam scan and then slowly narrowing the scan beam.

[0090] In some embodiments, once the RIS is configured using the frequency sweep and modulation configurations described above, the device or controller can activate the RIS at a given time for beam reflection and modulation, depending on the application or conditions. In some embodiments, the RIS may have a separate wake-up signal. In some embodiments, when the RIS has an active receiver unit, the wake-up signal is based on a specific received signal from the transmitter. Once the RIS is operational, the RIS controller can program its phase using received or otherwise acquired configuration information to reflect electromagnetic signals in the configured direction. Once a RIS reflection is decoded by the receiver, the receiver can perform an action based on the decoded message.

[0091] Refer again Figure 3 Embodiments of this disclosure provide single-base operation, wherein an electromagnetic signal transmitter and receiver are co-located, for example at a base station. Accordingly, the transmitter directs the electromagnetic signal to the RIS, which may be mounted on the UE. The co-located receiver receives the reflection of the electromagnetic signal from the RIS. The RIS is controlled by a programmable controller and may be provided with a backup battery dedicated to powering the RIS and the controller. The RIS may be implemented as an organic / inherent component of the UE physical device, or the RIS may be added to the UE physical device as a component mounted or otherwise operatively coupled.

[0092] Figure 5 An exemplary signal diagram according to an embodiment of this disclosure is shown. This signal diagram illustrates a setup phase, a maintenance phase, and a potential detection phase. It is assumed that the transmitter and receiver are associated with the BS, and the UE is active in each phase. Alternatively, the transmitter and receiver may be provided independently of the BS, and a controller or other terminal device (besides the UE) may be active. In the setup phase, the BS and UE engage in bidirectional active communication 510 to agree on configurations corresponding to different applications and to perform initial access 512 for the UE. The UE also transmits its capabilities and RIS capabilities 514 to the BS. The UE may also perform code sharing with the BS, whereby the BS may provide 516 instructions for RIS sweep configuration and / or message configuration to the UE. The UE may acknowledge 518 these instructions and may provide its own information to the BS. This setup phase or active communication phase 510 may also include a beam training interaction for configuring the operation of the transmitter and / or receiver. In the beam training interaction, the BS may perform a beam sweep to determine the baseline of the RIS reflection. The setup phase or active communication phase 510 can also be used to determine or transmit basic initial information, such as the current location of the UE / RIS, orientation or direction of travel (if the UE is moving), the type of material used in the RIS (frequency tuning to achieve the optimal reflection coefficient), etc.

[0093] Accordingly, during the setup phase, the RIS controller or its associated devices interact with the BS or another device associated with the electromagnetic signal transmitter and / or receiver. The RIS controller or its associated devices can then be configured to operate the RIS based on the information acquired during the setup phase.

[0094] For example, information acquired by the RIS controller or associated devices during the setup phase may include location information, such as the location of the transmitter or receiver of the electromagnetic signal. Information acquired during the setup phase may include the format the RIS uses to embed information into the electromagnetic signal and / or the modulation and coding scheme the RIS will use. Information acquired during the setup phase may include timing indications of the RIS's operation. Information acquired during the setup phase may include indications of the scan mode to be implemented by the RIS. During the setup phase, the RIS controller or associated devices may provide information such as indications that the RIS is capable of redirecting and modulating electromagnetic signals; the (e.g., approximate) location of the RIS; configuration information of the RIS or its associated devices; and indications of how to use the RIS to interpret a specified instance of information to be transmitted to the receiver.

[0095] Similarly, during the setup phase, the BS (or transmitter, receiver, or associated network device) can interact with the RIS controller or its associated devices. The BS or other device can then operate based on information acquired during the setup phase. This configuration may include settings for transmitting electromagnetic signals, monitoring reflections of electromagnetic signals, processing reflections, or combinations thereof. The configuration may include initializing parameters used in transmitting electromagnetic signals and / or processing reflections.

[0096] For example, information acquired by the BS or associated network device during the setup phase may include location information, such as the location of the RIS or its associated devices. Information acquired during the setup phase may include the format the RIS uses to embed information into electromagnetic signals and / or the modulation and coding scheme the RIS will use. Information acquired during the setup phase may include timing indications of the RIS's operation. Information acquired during the setup phase may include indications of the scan mode to be implemented by the RIS. The BS or associated network device may receive information during the setup phase, such as indications that the RIS is capable of redirecting and modulating electromagnetic signals; the (e.g., approximate) location of the RIS; configuration information of the RIS or its associated devices; and indications of how to use the RIS to interpret a specified instance of information to be transmitted to the receiver.

[0097] Once the first phase concludes, code sharing and agreement are reached, the configuration can be retained for a predetermined or agreed-upon period. During this pause, the BS may perform operations for the maintenance and potential detection phase. In some embodiments (applications), during this phase, the BS performs a periodic interrogation beam sweep 520 and monitors reflections of the interrogation beam. Beam sweeping involves sending electromagnetic signals in different directions (e.g., at different times). If a reflection is received, the BS processes the reflection to decode any information modulated into the reflection by the RIS. The BS can determine whether such information, if present, indicates a specific event such as SOS. The BS may also perform some passive beam sweeps to determine whether the agreed-upon configuration remains feasible or requires updating. The maintenance and potential detection phase relies on passive reflections from the RIS and does not necessarily involve any active RF transmissions from the UE.

[0098] More specifically, signaling between the BS and UE can begin with a connection. Subsequently, the UE can optionally notify the BS of its passive communication capabilities using a UE Capability Indicator (RIS). Once the BS is informed that the UE is capable of passive communication, it can send a frequency sweep and message configuration to the UE, which the UE can optionally acknowledge. Since the UE and RIS are co-located and connected, the UE can automatically configure the RIS using the frequency sweep and message configuration received from the BS. The RIS can be disabled until triggered by a controller or associated device (e.g., the UE). For example, triggering might occur when the UE has low power and needs to send messages according to the instructions in the message configuration from the BS.

[0099] It should be noted that the frequency sweep and message configuration may include all the information required to include specific information (e.g., a code) in the RIS reflected and modulated signals, or the configuration may have only partial information, with the remaining information required for such operation determined by the UE or specified by the standard. In the event of UE movement, the BS may optionally share some information with neighboring BSs. The BS may begin transmitting beams that sweep the frequency of the area assumed to be where the UE is located. This sweep may be periodic, aperiodic, or event-driven; for example, loss of connection with the UE. The BS may transmit such beams to test its ability to decode information transmitted via passive communication or to adjust parameters such as beam direction. The UE may trigger the RIS to begin passive communication such that when the BS beams are reflected from the RIS, they are modulated into a specific message. Once the BS receives the reflected beams from the RIS, it can decode these beams according to the agreed-upon message configuration to decode the UE message and perform actions accordingly. The message may be the UE ID, a code for a specific action, or typically low-rate information.

[0100] Refer again Figure 5The configuration or RIS reachability test 530 may include the BS sending electromagnetic signals 532 to the RIS. The RIS passively reflects at least one of these electromagnetic signals 534 back to the BS. The BS may also update its configuration settings and send an indication of the updated configuration settings to the UE 536. The update may be based on reflection, such as signal strength characteristics, bit error rate, determined UE location, time spent acquiring the reflection, etc. The update may include adjusting the modulation and coding scheme, frequency sweep schedule, etc. of the BS and / or the UE.

[0101] Once the UE or controller registers event 542, it causes the RIS to embed the corresponding code or other information into the reflection of the electromagnetic signal by modulating the RIS unit. Thereafter, any instance (copy) of the electromagnetic signal incident on the RIS will be reflected along with the embedded code or other information. In this example, the code indicates the UE ID and the associated short message. It is expected that at least one of these reflections will be reflected back to the BS at 544, for example, due to the RIS's sweep beamforming action. The BS will detect the UE ID at 546 and decode the message by decoding the reflection, and perform the relevant action. For example, if the message is SOS, the BS can trigger an alarm with the appropriate permissions. Receiving reflection 544 or the message itself can trigger the BS to send more electromagnetic signals at 548 to the RIS, possibly at a higher rate. The UE or controller can embed more information or repetitive information into the reflection of more electromagnetic signals through the RIS's modulation operation, and receive at least some reflections back at the BS at 550, where these reflections can be decoded and further actions can be performed if necessary.

[0102] In some embodiments, the BS (or transmitter) encodes information such as index, transmission time, or direction into each electromagnetic signal. The BS (or receiver) decodes any received, reflected electromagnetic signals to recover the encoded information (where modulation of the RIS does not destroy or mask such encoded information). For example, the information can be used to determine the specific time and / or direction of the swept electromagnetic signal that caused the reflection. The BS can then guide more electromagnetic signals using the same direction to increase the proportion of successfully reflected and received electromagnetic signals. This method can also be used to locate the RIS. The BS (or transmitter) can encode various information into electromagnetic signals for later decoding in received reflections for various purposes. In some embodiments (applications), the associated RIS can be used to scatter the input electromagnetic signal away from the receiver to hide the first device and disable sensing.

[0103] When applied to specific applications, the signaling in this embodiment can be simplified. In one example, the UE / RIS is a traffic light, while the transmitter and receiver are integrated into the car. When the car stops at the traffic light, beamforming is performed in the direction of the traffic light. This beam, modulated by the RIS, will include information about the remaining seconds before the traffic light turns green. In this case, beamforming is only performed when the car stops at a red light, while the traffic light modulates any beam to include information about the remaining seconds before the green light while it is red. No capability signaling, message configuration, or frequency sweep configuration is required, as these operations are likely to be performed in a standard manner. Therefore, the traffic light is the device, and the transmitter and receiver (equivalent to the BS) are the car. The information encoded in the electromagnetic signal reflection is the traffic light's state information, such as the remaining time before the light changes color.

[0104] In another example, the UE is a car, and the transmitter is a traffic device that directs a signal beam at a section of the road. Passing vehicles modulate traffic information through this beam, such as speed, license plate number, and driver information. In a third example, the UE is a car or bicycle, and the transmitter is a parking lot device that periodically sends a beam. The UE responds with its own location information to help drivers locate their vehicles or bicycles in large parking lots. Therefore, the car is the device, and the transmitter and receiver (equivalent to the BS) are roadside or parking lot equipment. The information encoded in the reflected electromagnetic signal includes the car's identity information or other relevant operational or status information.

[0105] As can be seen from the signaling and examples above, the selected signaling can be used to implement application-specific passive communication. It should be noted that this disclosure generally relates to passive communication, and not all steps described herein are necessary for every application.

[0106] The embodiments shown above primarily assume that the transmitter and receiver are co-located, similar to a monostatic radar or sensing setup. However, in some embodiments, the transmitter and receiver are located in different locations, similar to a bistatic radar or sensing setup, for example... Figure 6As shown in the diagram. In this scenario, transmitter 630 (e.g., at the first BS) transmits an electromagnetic signal 632, which is modulated and reflected by the RIS of UE 210, and received at receiver 635, located at a different location from transmitter 630, a reflection 637. However, in such embodiments, transmitters and receivers at different locations can generally still coordinate with each other using a communication channel (or internal link) separate from the communication channel carrying the electromagnetic signal. In other words, the transmitter and receiver are not only communicationally coupled through the electromagnetic signal itself. For example, the transmitter and receiver can communicate through another wired, wireless, optical, or networked communication medium. This allows the transmitter and receiver to coordinate the transmission of electromagnetic signals so that the same entity controls the operation of both the transmitter and receiver, so that the receiver reports information embedded in the reflection, RIS location information, information about which directions of transmission cause the RIS reflection, etc., or a combination of such information. In some embodiments, the transmitter is associated with a base station or other control device, and the receiver reports its information back to that control device. However, the control device may be located at the receiver or other locations within the network infrastructure.

[0107] Electromagnetic signals and their reflections can reach and / or originate from the RIS via line-of-sight or non-line-of-sight paths. That is, like many electromagnetic signals, this electromagnetic signal can be reflected by one or more objects that appear by chance or are intentionally placed. One such object is the RIS. Figure 7 A monobase embodiment is illustrated, in which an electromagnetic signal from a base station (BS) (or transmitter) 730 is reflected by a first RIS 737 and then further reflected by a RIS of device 210. The reflection from the RIS of the device can also be further reflected by the first RIS 737 and then received at the BS (or receiver co-located with the transmitter) 730. This can be referred to as a monobase embodiment with RIS extension. Thus, the electromagnetic signal can be redirected by additional RISs before and / or after the modulated RIS incident on the device. One or more of these additional RISs may also modulate the electromagnetic signal. The RIS is fixed and in an intermediate position. In some embodiments, more RISs in intermediate positions may be included. Furthermore, the intermediate RISs in these embodiments can typically perform the required beam scanning instead of being performed by the transmitter, by adjusting the angle at which the electromagnetic signal is reflected to intercept the RIS of the device (which may be located in an unknown location). The intermediate RIS can further scan the reflection in a similar manner, for example, by maintaining its configuration for a sufficiently long time to reflect the electromagnetic signal back to the base station (or transmitter).

[0108] Figure 8A bistatic embodiment of the extended RIS is illustrated. In this case, the transmitter 830 and receiver 835 are located in different positions. A first RIS 837 reflects the electromagnetic signal from the transmitter 830 back to the RIS of device 210. The first RIS 837 further reflects the electromagnetic signal (from the RIS of the device) toward the receiver 835. The first RIS 837 can perform beamforming operations to achieve time-varying frequency sweeps or scans of the electromagnetic signal and / or its reflections. Additional RISs can also be provided to redirect the electromagnetic signal and / or its reflections.

[0109] Figure 9 This is a schematic diagram of an electronic device 900 according to different embodiments of the present invention, which can perform at least some of the operations of the methods and features described herein, either explicitly or implicitly. For example, a computer equipped with network capabilities can be configured as electronic device 900. Such electronic device can be used as part of one or more of the following: a controller, an edge server, a processing device, a UE, a base station, a transmitter, a receiver, etc.

[0110] As shown, the device includes a processor 910 (e.g., a central processing unit (CPU) or a dedicated processor, such as a graphics processing unit (GPU), or other such processor units), a memory 920, a non-transient mass storage element 930, an I / O interface 940, a network interface 950, and a transceiver 960, all of which are communicatively coupled via a bidirectional bus 970. According to a particular embodiment, any or all of the elements shown may be utilized, or only a subset of the elements may be used. Furthermore, the device 900 may include multiple instances of specific elements, such as multiple processors, memories, or transceivers. Additionally, units in the hardware device may be directly coupled to other units without a bidirectional bus. Other electronic devices, such as integrated circuits, may be employed to perform the required logical operations as a supplement to or alternative to the processor and memory.

[0111] Memory 920 may include any type of non-transitory memory, such as static random access memory (SRAM), dynamic random access memory (DRAM), synchronous DRAM (SDRAM), read-only memory (ROM), or combinations thereof. Mass storage element 930 may include any type of non-transitory storage device, such as a solid-state drive, hard disk drive, disk drive, optical disk drive, USB drive, or any computer program product configured to store data and machine-executable program code. According to a particular embodiment, memory 920 or mass storage element 930 may record statements and instructions executable by processor 910 thereon for performing any of the above-described method operations.

[0112] It should be understood that while specific embodiments of the technology have been described herein for illustrative purposes, various modifications can be made without departing from the scope of the technology. Therefore, the specification and drawings are to be considered merely as a description of the invention as defined in the appended claims, and are intended to cover any and all modifications, variations, combinations, or equivalents falling within the scope of the invention. Specifically, computer program products or program elements for storing machine-readable signals, or program storage or memory devices such as magnetic wires, optical fibers, magnetic tapes, or disks, are provided within the scope of this technology for controlling the operation of a computer according to the method of this technology and / or constructing some or all of its components according to the system of this technology.

[0113] The actions associated with the method described herein can be implemented as coded instructions in a computer program product. In other words, a computer program product is a computer-readable medium on which software code is recorded, which executes the method when the computer program product is loaded into memory and executed on the microprocessor of a wireless communication device.

[0114] Furthermore, each operation of this method can be performed on any computing device such as a personal computer, server, or PDA, based on one or more program units, modules, or objects, or a portion thereof, generated from any programming language such as C++ or Java. Additionally, each operation, or the file or object implementing each operation, can be performed by dedicated hardware or a circuit module designed for this purpose.

[0115] Based on the description of the above embodiments, the present invention can be implemented using only hardware, or using software and necessary general-purpose hardware platforms. Based on this understanding, the technical solution of the present invention can be embodied in the form of a software product. The software product can be stored in a non-volatile or non-transitory storage medium, such as a compact disk read-only memory (CD-ROM), a USB flash drive, or a removable hard drive. The software product includes a number of instructions that enable a computer device (personal computer, server, or network device) to perform the methods provided in the embodiments of the present invention. For example, such execution may correspond to the simulation of the logical operations described herein. According to embodiments of the present invention, the software product may additionally or alternatively include a plurality of instructions that enable a computer device to perform operations for configuring or programming digital logic devices.

[0116] Although the invention has been described with reference to specific features and embodiments thereof, it will be apparent that various modifications and combinations thereof can be made without departing from the invention. Therefore, the specification and drawings are to be regarded merely as illustrative of the invention as defined by the appended claims and are intended to cover any and all modifications, variations, combinations, or equivalents falling within the scope of the invention.

[0117] The embodiments described above in conjunction with various aspects of the present invention can be implemented based on these aspects. Those skilled in the art will understand that embodiments can be implemented in conjunction with the aspects described therein, but also in conjunction with other embodiments of that aspect. It will be apparent to those skilled in the art that embodiments are mutually exclusive or contradictory. Some embodiments may be described in conjunction with one aspect, but may also be applicable to other aspects, as will be apparent to those skilled in the art.

Claims

1. An apparatus, characterized in that, include: A reconfigurable smart surface (RIS) for interacting with incident electromagnetic signals from a transmitter; Controller, used to operate the RIS to: Beamforming is used to redirect the electromagnetic signal in a direction that is received by a receiver, which cooperates with the transmitter to interrogate the device using the electromagnetic signal. Simultaneously modulate the electromagnetic signal to include information to be transmitted to the receiver; The device is used to obtain the information from a first device co-located with the device, the first device being: a communication network terminal device, or a device having a practical application rather than being a network infrastructure device.

2. The apparatus according to claim 1, characterized in that, The first device and the RIS can move together, and the RIS can be redirected, wherein the controller responds to the movement of the RIS and the redirection of the RIS to adjust the redirection of the electromagnetic signal.

3. The apparatus according to claim 1 or 2, characterized in that, The first device is a device that does not have long-distance wireless transmission capability except for relying on the RIS.

4. The apparatus according to claim 1 or 2, characterized in that, The first device is a user equipment (UE) device.

5. The apparatus according to any one of claims 1 to 4, characterized in that, The information includes one or more of the following: the location of the first device, the identifier of the first device, the distress signal of the first device, and the status of the first device.

6. The apparatus according to any one of claims 1 to 5, characterized in that, The controller is also used for: For each of the multiple incident signals, each incident signal corresponds to one of a plurality of different time intervals: The RIS is reconfigured to redirect the incident signal in different corresponding directions of the scanning mode; The RIS is operated to simultaneously modulate the incident signal to include the information. One of the plurality of incident signals is represented by the electromagnetic signal.

7. The apparatus according to claim 6, characterized in that, The scanning mode is configured based on previously acquired information indicating a range of directions, which includes directions received by the receiver.

8. The apparatus according to claim 7, characterized in that, The scanning mode is also configured based on the spatial orientation perceived by the RIS.

9. The apparatus according to any one of claims 1 to 8, characterized in that, The transmitter and the receiver share the same address.

10. The apparatus according to any one of claims 1 to 8, characterized in that, The transmitter and the receiver are located in different locations.

11. The apparatus according to any one of claims 1 to 10, characterized in that, The electromagnetic signal is a sensing signal generated, transmitted, and received according to radar or sensing communication integrated ISAC operation.

12. The apparatus according to any one of claims 1 to 11, characterized in that, The transmitter and the receiver coordinate with each other via a first communication channel or an internal link, and the electromagnetic signal is transmitted and received via a second communication channel separate from the first communication channel.

13. The apparatus according to any one of claims 1 to 12, characterized in that, The direction received by the receiver is a direction known to the controller based on one or more of the following: The spatial orientation sensed by the RIS; Information previously acquired during the setup phase.

14. The apparatus according to any one of claims 1 to 13, characterized in that, The first device is used for: During the setup phase, the device interacts wirelessly with the transmitter, or a second device associated with the transmitter and / or the receiver. Configure the controller to operate the RIS based on information acquired during the setup phase.

15. The apparatus according to claim 14, characterized in that, The information acquired during the setup phase includes one or more of the following: the location of the transmitter, the location of the receiver, the location of the device, the location of the first device; the format of the information; an indication of the modulation and coding scheme to be used by the device when modulating the electromagnetic signal; and an indication of the operating timing of the RIS. An indication of the scanning mode to be implemented by the device for redirecting the electromagnetic signal in different directions.

16. The apparatus according to claim 14 or 15, characterized in that, The interactions during the setup phase include beam training interactions for configuring the operation of the transmitter and / or the receiver.

17. The apparatus according to any one of claims 1 to 16, characterized in that, The RIS is installed into the first device.

18. The apparatus according to any one of claims 1 to 17, characterized in that, The RIS is operatively coupled to the first device via a short-range wireless communication link.

19. The apparatus according to any one of claims 1 to 18, characterized in that, The controller is used to start operating the RIS in response to a trigger from the first device.

20. The apparatus according to any one of claims 1 to 19, characterized in that, Modulating the electromagnetic signal includes phase modulation and / or amplitude modulation.

21. The apparatus according to any one of claims 1 to 20, characterized in that, The transmitter and the receiver further cooperate to locate the device by guiding the electromagnetic signal and processing the reflection of the electromagnetic signal from the RIS.

22. A system, characterized in that, include: The apparatus according to any one of claims 1 to 21, and the first device co-located with the apparatus.

23. An apparatus, characterized in that, include: A transmitter for sending electromagnetic signals to the reconfigurable smart surface RIS; A receiver, cooperating with the transmitter to interrogate a first device associated with the RIS using the electromagnetic signal, the receiver being used to monitor and receive reflections of the electromagnetic signal from the RIS; The apparatus is also used to process the reflection to recover information therefrom, the information being included in the reflection by modulating the electromagnetic signal by the RIS, wherein the information included in the reflection is provided from the first device associated with the RIS, the first device being: a communication network terminal device, or a device having a practical application rather than being a network infrastructure device.

24. The apparatus according to claim 23, characterized in that, The first device is a user equipment (UE) device.

25. The apparatus according to any one of claims 23 to 24, characterized in that, The transmitter and the receiver cooperate with each other via a first communication channel or internal link to interrogate the first device, and the electromagnetic signal is transmitted and received via a second communication channel separate from the first communication channel.

26. The apparatus according to claim 25, characterized in that, After recovering the information, the receiver reports it to the transmitter or another device controlling the transmitter.

27. The apparatus according to any one of claims 23 to 26, characterized in that, The electromagnetic signal is an object sensing signal generated, transmitted, and received according to radar or sensing communication integrated ISAC operation.

28. The apparatus according to any one of claims 23 to 27, characterized in that, The transmitter and the receiver share the same address.

29. The apparatus according to any one of claims 23 to 27, characterized in that, The transmitter and the receiver are located in different locations.

30. The apparatus according to any one of claims 23 to 29, characterized in that, The transmitter is used to sequentially send the electromagnetic signals in each of a plurality of different directions according to a scanning pattern.

31. The apparatus according to claim 30, characterized in that, The scanning pattern is based on previously acquired information indicating a range of directions, including directions toward the RIS.

32. The apparatus according to any one of claims 23 to 31, characterized in that, The information includes one or more of the following: the location of the first device, the identifier of the first device, the distress signal of the first device, and the status of the first device.

33. The apparatus according to any one of claims 23 to 32, characterized in that, The device is used for: During the setup phase, the device interacts with the first device wirelessly. The device is configured to operate based on information acquired during the setup phase to perform operations such as transmitting the electromagnetic signal, monitoring the reflection, processing the reflection, or any combination thereof.

34. The apparatus according to claim 33, characterized in that, The information acquired during the setup phase includes one or more of the following: the location of the RIS, the location of the first device; the format of the information; an indication of the modulation coding scheme to be used by the RIS when modulating the electromagnetic signal; an indication of the operating timing of the RIS; and an indication of the scanning mode to be implemented by the RIS for redirecting the electromagnetic signal in different directions.

35. The apparatus according to claim 33 or 34, characterized in that, The interaction during the setup phase includes receiving one or more of the following at the device: an indication that the RIS is capable of redirecting and modulating the electromagnetic signal; the location of the RIS; configuration information of the RIS or the first device; the format of the information; an indication of how to use the RIS to interpret a specified instance of the information; an indication of the modulation coding scheme to be used by the RIS when modulating the electromagnetic signal; an indication of the operating timing of the RIS; and an indication of the scanning mode to be implemented by the RIS for redirecting the electromagnetic signal in different directions.

36. The apparatus according to any one of claims 23 to 32, characterized in that, Also used for: During the setup phase, the device interacts wirelessly with the first device associated with the RIS to initialize parameters that can be used to send the electromagnetic signals and / or process the reflections.

37. The apparatus according to any one of claims 23 to 36, characterized in that, The electromagnetic signal is modulated using phase modulation and / or amplitude modulation.

38. A method performed by a device, characterized in that, The method includes: Information to be sent to the receiver is obtained from a first device co-located with the device, wherein the first device is: a communication network terminal device, or a device having a practical application rather than being a network infrastructure device; The operable reconfigurable smart surface RIS interacts with an incident electromagnetic signal transmitted by a transmitter, the interaction including: Beamforming is used to redirect the electromagnetic signal in a direction that is received by a receiver, which cooperates with the transmitter to interrogate the device using the electromagnetic signal. Simultaneously modulate the electromagnetic signal to include the information.

39. The method according to claim 38, characterized in that, The information includes one or more of the following: the location of the first device, the identifier of the first device, the distress signal of the first device, and the status of the first device.

40. The method according to claim 38 or 39, characterized in that, Also includes: For each of the multiple incident signals, each incident signal corresponds to one of a plurality of different time intervals: The RIS is reconfigured to redirect the incident signal in different corresponding directions of the scanning mode; The RIS is operated to simultaneously modulate the incident signal to include the information. One of the plurality of incident signals is represented by the interrogation signal.

41. A method, characterized in that, include: Electromagnetic signals are sent to the reconfigurable smart surface RIS via a transmitter. A receiver cooperating with the transmitter uses the electromagnetic signal to interrogate a first device associated with the RIS, the receiver being used to monitor and receive reflections of the electromagnetic signal from the RIS; The reflection is processed to recover information therefrom, the information being included in the reflection by modulating the electromagnetic signal through the RIS.

42. The method according to claim 41, characterized in that, The information included in the reflection is provided from the first device associated with the RIS, which is a communication network terminal device or a device with a practical application rather than as a network infrastructure device.

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