System, panel device and method for passive reflection of RF signals

Abstract

A system for reflecting RF signals comprises a reference antenna (6') and a plurality of antenna elements (2) for receiving and passively reflecting RF signals. Each antenna element (2) comprises a respective phase shifter (8) operable to adjustably impart a phase change to an RF signal before it is reflected. The system can be a large intelligent surface LLS, and the antenna elements can be comprised in an arrangement of separate panel devices. A control system (20) is configured to: operate the respective phase shifters (8) to phase align first analog antenna signals ASn respectively received by the respective antenna elements (2) and a first analog reference signal REF in response to a first RF signal by the respective antenna elements (2) and the reference antenna (6'); determine, for the respective phase shifters (8), first phase settings that result in the phase alignment; and store the first phase settings. The first phase settings enable the system to perform beamforming in reception and / or reflection with substantially no power consumption.

Description

Technical Field

[0001] This disclosure relates generally to wireless communication, and more specifically to techniques for passively reflecting RF (radio frequency) signals from one device to another. Background Technology

[0002] In wireless communication, it is advantageous to have multiple antennas and position them near the user. Ultimately, it is desirable to install antennas anywhere around the user.

[0003] Recently, the concept of a large-scale intelligent surface (LIS) has been proposed. The LIS concept can be viewed as an extension of traditional massive MIMO, scaled up beyond the traditional large antenna array concept. The vision is to provide a low-hardware-footprint structure that can be deployed on or within building facades, walls and ceilings of rooms and factories. However, massive MIMO requires digital baseband processing of antenna signals to focus energy in three-dimensional space. Since the LIS concept involves a large number of antennas, the same number of antenna signals must be processed, whether locally at the antennas or at a central processing unit. This data processing is difficult to achieve with a reasonable response time and results in excessive power consumption.

[0004] To overcome these drawbacks, C. Huang et al., in their paper "Large Intelligent Surfaces for Energy Efficiency in Wireless Communication" published in arXiv:1810.06934, proposed a type of LIS (Limited Inductive Surface) with a large number of small, nearly passive reflective elements with reconfigurable parameters. Each LIS reflective element can effectively reflect a phase-shifted version of the impact electromagnetic field, and the LIS is described as performing as a scatterer with reconfigurable properties without performing decoding, channel estimation, or transmission.

[0005] However, while the above articles outline the concept of passive LIS and present a theoretical analysis of how to maximize energy efficiency in outdoor LIS-assisted multi-user downlink communication, there is still important inventive activity to make the concept of passive LIS useful in practice.

[0006] Existing technology also includes the article "Intelligent Reflecting Surface Enhanced Wireless Network: Joint Active and Passive beamforming Design" published by Q. Wu and R. Zhang in IEEE Transactions on Wireless Communications, vol. 18, no. 11, pp. 5394-5409, Nov. 2019. Here, a single-antenna UE is directly linked to a multi-antenna AP via a LIS (referred to as "Intelligent Reflecting Surface" (IRS)). To achieve this link, the active transmission at the AP and the reflection of the phase shifter at the IRS are jointly optimized to maximize the total signal power received at the UE. In the distributed optimization algorithm, the AP and IRS independently adjust the transmit beamforming and phase shift in an alternating manner until convergence is achieved. This optimization requires repeated signal exchange between all three devices (UE, AP, and IRS) and may be difficult to implement in practice. Summary of the Invention

[0007] One objective is to overcome, at least partially, one or more limitations of the existing technology.

[0008] Another objective is to provide a technique for receiving RF signals at multiple antennas and focusing the RF signals in three-dimensional space without baseband processing.

[0009] One or more of these objectives, and other objectives that may arise from the following description, are achieved, at least in part, by a system for reflecting RF signals, a panel device, a method in a system for reflecting RF signals, and a computer-readable medium.

[0010] Some implementations relate to systems comprising multiple antenna elements configured to receive and passively reflect RF signals, wherein each antenna element includes a corresponding phase shifter operationally for adjustably applying a phase change to the RF signal before it is reflected. The system is passive in the sense that the reflection occurs without digital signal processing of the incoming RF signal. The system can be a passive LIS as described above, or any other dynamically configurable and passive RF reflection system. To enable the system to perform beamforming of the RF signal in both reception and reflection, the system also includes a reference antenna. In some implementations, the control system is configured to: operate the corresponding phase shifter to phase-align a first analog antenna signal received by the corresponding antenna element with a first analog reference signal received by the reference antenna in response to a first RF signal from a first device; determine a first phase setting for the corresponding phase shifter; and store the first phase setting. The first phase setting of the phase shifter enables the system to perform beamforming in both reception and / or reflection. Phase alignment is achieved by operating the analog signal through a phase shifter (i.e., without baseband processing) and can be performed automatically, quickly, and efficiently by an analog controller (e.g., in the corresponding antenna element).

[0011] Further objects, features, aspects and technical effects will become apparent from the following detailed description, the appended claims and the accompanying drawings. Attached Figure Description

[0012] The implementation will now be described in more detail with reference to the accompanying diagrams.

[0013] Figure 1 This is a 3D view of a user device interacting with a large intelligent surface (LIS).

[0014] Figure 2A This is a partial cross-sectional side view of the panel device according to the embodiment. Figure 2B It is a top view of the panel device, and Figure 2C This is a circuit diagram of the antenna unit in a panel device.

[0015] Figure 3A This is a flowchart of an example method for training and operating a passive reflective panel device, and Figure 3B This is an example of the operating status of the panel device.

[0016] Figures 4A to 4C The training and operation of the panel device in relation to two wireless devices are illustrated.

[0017] Figures 5A to 5B This is a schematic circuit diagram of an example structure for phase adjustment of an antenna element.

[0018] Figure 6AThis is a side view of a pair of panel devices used in passive reflective coherent operation. Figure 6B It is a 3D view of multiple panel devices in coherent operation. Figure 6C This is a partial cross-sectional side view of two panel devices according to an embodiment, and Figures 6D to 6E An example of coherent operation for a selected panel used for passive reflection is shown.

[0019] Figures 7A to 7B An example of a panel device performing passive reflective coherent operation via coherent signal reception at one panel device and coherent signal transmission at another panel device is illustrated.

[0020] Figure 8 This is a circuit diagram of an antenna unit according to an implementation method.

[0021] Figure 9 This is an example sequence diagram of the configuration process in the system of a panel device. Detailed Implementation

[0022] Embodiments will now be described more fully below with reference to the accompanying drawings, which illustrate some, but not all, of the embodiments. In fact, the subject matter of this disclosure may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided to enable this disclosure to meet applicable legal requirements. The same reference numerals throughout refer to the same elements.

[0023] Furthermore, it will be understood that, where possible, any advantage, feature, function, device, and / or operational aspect of any implementation of any of the embodiments described and / or contemplated herein may be included in any other implementation of the embodiments described and / or contemplated herein, and / or vice versa. Additionally, where possible, unless expressly stated otherwise, any term expressed in the singular herein means to include the plural form as well, and / or vice versa. As used herein, “at least one” should mean “one or more,” and these phrases are intended to be interchangeable. Thus, the terms “a” and / or “one” should mean “at least one” or “one or more,” even though the phrases “one or more” or “at least one” are used herein. As used herein, unless the context requires otherwise due to the language of expression or necessary implication, the word “comprising” or variations such as “comprises” or “comprising” are used in an inclusive sense, that is, specifying the presence of the stated feature but not excluding the presence or addition of additional features in various embodiments.

[0024] Furthermore, it will be understood that while the terms first, second, etc., may be used herein to describe various elements, these elements should not be limited by these terms. These terms are used only to distinguish one element from another. For example, without departing from the scope of this disclosure, a first element may be referred to as a second element, and similarly, a second element may be referred to as a first element. As used herein, the term “and / or” includes any and all combinations of one or more of the associated listed terms.

[0025] As used herein, “RF signal” is any electromagnetic signal used for wireless communication and includes electromagnetic waves having frequencies in the radio spectrum (i.e., the frequency range from 30 Hz to 300 GHz).

[0026] As used herein, "passive reflection" refers to the reflection or retransmission of an incoming RF signal without digital signal processing (e.g., decoding or channel estimation) of the RF signal. Preferably, "passive reflection" also implies a reflection in which no energy is added to the incoming RF signal (e.g., by amplification) before retransmission.

[0027] As used herein, “beamforming” is used in its common sense and refers to the technique of manipulating an antenna array to achieve spatial beam focusing of incoming or outgoing RF signals. Therefore, beamforming can be performed “in reception,” meaning that analog antenna signals received at different antennas used for the incoming RF signal are combined to achieve constructive interference for a specific input direction and optimally focus the spatial beam at the source of the incoming RF signal. Beamforming can also be performed “in reflection,” meaning that analog antenna signals corresponding to the incoming RF signals at different antennas are modulated to achieve constructive interference for a specific output direction and optimally focus the spatial beam at the intended receiver of the reflected RF signal.

[0028] As used in this article, "phase alignment" refers to adjusting two or more analog signals to be in phase with each other. Furthermore, "coherent combination" refers to combining phase-aligned analog signals by addition.

[0029] As used herein, “antenna” refers to an antenna element or a surface configured to receive incoming RF signal waves and convert the RF signal waves into analog signals (e.g., oscillating current).

[0030] The implementation relates to a technique for receiving RF signals at multiple antenna elements and focusing the RF signals in 3D space without digital signal processing. Antenna elements are included in a system that is operationally used to control the antenna elements to passively reflect incoming RF signals. The number of antenna elements is large. In a non-limiting example, the number of antenna elements is 100,000 or more. The antenna elements can be fixedly arranged, for example, distributed across one or more support structures.

[0031] The implementation method is applicable to any standardized or proprietary radio-based communication technology, including but not limited to 5G NR, 4G LTE, 3G, Wi-Fi, WiMAX, etc.

[0032] Figure 1 An example of System (LIS) 1 is shown, which is deployed to establish communication links to one or more destination nodes (not shown) (e.g., other user equipment or one or more base stations (BS)) for various communication devices D1-D3 (e.g., user equipment (UE) as shown). Figure 1 It is understood that LIS 1 defines a large surface structure that can be arranged, for example, on the wall of a building (not shown). LIS 1 is used to reflect incoming RF signals from D1-D3 to the corresponding destination node using beamforming. Due to the large range of LIS 1, LIS 1 will define a large aperture and collect most of the radiated energy from D1-D3 (as shown by the corresponding circular area on LIS 1), and beamform it about the destination node. This results in significant array gain and spatial focusing for achieving substantial energy savings and thus enabling green communication. For example, the radiated power of D1-D3 may be so low that D1-D3 cannot directly establish any communication link with the corresponding destination node without the assistance of LIS 1.

[0033] The implementation described herein assumes that the reflection and beamforming of LIS 1 are passive processes, i.e., no buffering or baseband processing of the incoming RF signal is involved in LIS 1. A challenge in this context is achieving beamforming in both reception and reflection without digital signal processing.

[0034] Figure 2A This is an elevated side view of a system for reflecting RF signals according to some embodiments. The system includes a panel device 1 with a plate-like housing, which includes a support structure 3. Multiple antenna elements 2 are fixed to the support structure 3 and distributed across the support structure 3 (e.g., as shown in...). Figure 2B(The top view illustrates a two-dimensional form). Panel device 1 includes a reference antenna 6', which is fixed to support structure 3 and electrically connected to antenna element 2. Antenna element 2 can be individually reconfigured to passively receive and reflect incoming RF signals using beamforming in both reception and reflection. To achieve beamforming in a selected direction, antenna element 2 is configured to modify the characteristics of an analog signal (“antenna signal”) corresponding to the incoming RF signal based on an analog reference signal from reference antenna 6'. In the following description, it is assumed that the characteristic is phase, and antenna element 2 is configured to impart a controlled phase shift (or equivalently, a time delay) to the antenna signal.

[0035] The overall operation of panel device 1 is controlled by control device 1A, which includes any type of processing device 4, such as a microprocessor, microcontroller, DSP, CPU, etc. Processing device 4 is connected to antenna unit 2 and memory device 5 in control unit 1A. Memory device 5 may include one or more of a buffer, flash memory, hard disk drive, removable media, volatile memory, non-volatile memory, random access memory (RAM), or another suitable device. Processing device 4 can execute instructions stored in memory device 5 to control the operation of panel device 1. When executed by processing device 4, the instructions can cause panel device 1 to perform any or part of the methods described herein. Software instructions that may be provided to control device 1A reside on a computer-readable medium, such as a tangible (non-transitory) product or a propagating signal, such as magnetic media, optical disc, read-only memory, flash memory, etc.

[0036] It is worth noting that, Figure 2A The system described here is entirely different from existing MIMO, beamforming, decoding and relay, and backscatter communication paradigms, which involve RF processing, decoding, encoding, and retransmission. Instead, panel device 1 includes a large number of passive elements that reflect incident RF signals with selected phases to achieve beamforming in a selected direction, and preferably with respect to both the originating communication device and the destination node.

[0037] Figure 2CAn example of antenna element 2 is schematically depicted. Antenna element 2 includes an antenna 6 connected in a conductive path to an RF reflecting element 7, which reflects an analog antenna signal ASn generated by antenna 6 in response to an incoming RF signal. In the illustrated example, RF reflecting element 7 is a ground plane. In another example, RF reflecting element 7 is defined by another type of discontinuity (e.g., an open end) in the characteristic impedance of the conductive path. A tunable phase shifter 8 is disposed in series with antenna 6 in the conductive path. Phase shifter 8 is used to modify the phase of the antenna signal, for example, by modifying its capacitance and / or inductance or otherwise delaying the antenna signal time. In a non-limiting example, phase shifter 8 is a varactor diode or inductor. Antenna element 2 also includes a local control device 20, which includes a phase comparator 21 and a phase controller 22. Phase comparator 21 is arranged to receive the antenna signal from a coupler or switch 8A in the conductive path, receive a reference signal REF from a reference antenna 6', and output a measurement signal indicating the phase difference between these signals. Coupler / switch 8A is a passive element disposed between phase shifter 8 and RF reflector 7. Coupler / switch 8A may be a directional element configured to transfer power flowing in one direction (towards or away from RF reflector 7) in the conductive path only to phase comparator 21. Phase controller 22 may operate in an adaptive or static state. In adaptive state, phase controller 22 adjusts phase shifter 8 to achieve a predefined criterion substantially corresponding to phase alignment of antenna signal and reference signal. The predefined criterion may be one or more signal values ​​from or calculated from phase comparator 21 that are equal to, higher than, or lower than a target value, or within a range of a target value. In adaptive state, local control device 20 operates a control loop defined by analog circuitry to automatically determine the phase shifter 8 settings that result in phase alignment. In static state, phase controller 22 applies predetermined settings to phase shifter 8. Phase controller 22 may retrieve predetermined settings from local memory (not shown) in antenna unit 2, or predetermined settings may be retrieved from memory 5 by processor 4 and provided to phase controller 22. The phase controller 22 can switch between an adaptive state and a static state based on a control signal C1 from the processor 4. In the context of this disclosure, the control device 1A and the local control device 20 in the antenna unit 2 are considered to jointly define the “control system” of the panel device 1.

[0038] The reference antenna 6' can be a dedicated antenna in system 1. Alternatively, the antenna of one of the antenna elements in antenna element 2 of system 1 can be deployed as the reference antenna, provided that the phase shifters are set to a fixed phase value (e.g., zero) in adaptive states R1, R2 (hereinafter).

[0039] Figure 3A and Figure 3B An example method that can be executed by the control system of a panel device is illustrated. During the execution of this method, the control system sets the panel device to different modes or states: a first adaptive state R1, a second adaptive state R2, and a static reflective state R12. (Refer to...) Figures 4A to 4C To illustrate this method, an example is provided. Figures 4A to 4C A first communication device D1 and a second communication device D2 are illustrated, which transmit RF signals received by panel device 1. Although D1 is illustrated as a base station and D2 as a mobile phone, the corresponding RF signals can originate from any type of fixed or mobile communication device, including but not limited to mobile phones, PDAs, laptops, base stations, wearable computers, wireless sensors, etc.

[0040] In the first adaptive state R1, panel device 1 receives the first RF signal from D1 (step 301), such as Figure 4A As shown. The first RF signal is received by antenna 6 and a corresponding first analog antenna signal is generated. The first RF signal is also received by reference antenna 6' and a first analog reference signal is generated. In step 302, the corresponding phase shifter 8 is operated to align the first analog antenna signal with the first analog reference signal in phase (e.g., as shown above). Figure 2C As described above, the first phase setting of the corresponding phase shifter 8 is determined. Therefore, the first phase setting is the setting (phase) of the corresponding phase shifter 8 used to achieve phase alignment between the first analog antenna signal and the first analog reference signal, thereby achieving phase alignment of the first analog antenna signal of the antenna element 2. It can be noted that the phase alignment of the first antenna signal allows the panel device 1 to retroreflect the first RF signal to D1 using beamforming. In step 303, the first phase setting is stored, for example, in the local memory of the corresponding antenna element or in the memory unit 5.

[0041] In the second adaptive state R2, panel device 1 receives the second RF signal from D2 (step 304), such as Figure 4B As shown. The second RF signal is received by antenna 6 and a corresponding second analog antenna signal is generated. The second RF signal is also received by reference antenna 6' and a second analog reference signal is generated. In step 305, the corresponding phase shifter 8 is operated to align the second analog antenna signal with the second analog reference signal in phase (e.g., as shown above). Figure 2C(As described), and determines the second phase setting of the corresponding phase shifter 8. Therefore, the second phase setting is the setting (phase) of the corresponding phase shifter 8, which is used to achieve phase alignment between the second analog antenna signal and the second analog reference signal, thereby achieving phase alignment of the second analog antenna signal of the antenna element 2. The phase alignment of the second antenna signal allows the panel device 1 to retroreflect the second RF signal to D2 using beamforming. In step 306, the second phase setting and / or the combined phase setting given by the combination of the first phase setting and the second phase setting are stored, for example, in the local memory of the corresponding antenna element or in the memory unit 5. Alternatively, the second phase setting or the combined phase setting can be stored by being applied to the phase shifter 8 to lock the phase shifter.

[0042] In static reflection state R12, the combined phase setting is applied to phase shifter 8 (step 307). Depending on the implementation, step 307 can retrieve the first phase setting and the second phase setting from memory and calculate the combined phase setting, or step 307 can retrieve the combined phase setting from memory. Alternatively, step 307 can be performed by locking the phase shifter in step 306. By applying the combined phase setting to the phase shifter, panel device 1 is operationally used to receive an RF signal from D1 using beamforming associated with D1, and to retransmit (reflect) the RF signal using beamforming associated with D2. Similarly, panel device 1 is operationally used to receive an RF signal from D2 using beamforming associated with D2, and to retransmit (reflect) the RF signal using beamforming associated with D1. Thus, a communication link can be established between D1 and D2 via panel device 1, such as... Figure 4C As shown.

[0043] In a non-limiting example, step 302 can result in a phase setting θ1 for phase shifter 8 to achieve phase alignment in state R1, and step 305 can result in a phase setting θ2 for phase shifter 8 to achieve phase alignment in state R2. The combined phase setting of phase shifter 8 to be used in R12 is calculated as the average of θ1 and θ2, i.e., (θ1+θ2) / 2. This calculation can be performed for each antenna element in panel device 1.

[0044] Figure 3BSome envisioned static and adaptive states of panel device 1 are listed, including states R1, R2, and R12 mentioned above. In addition to these states, panel device 1 can obtain a static first retroreflection state RR1, in which the phase shifter 8 is configured to retroreflect the incoming RF signal from D1. In RR1, a phase setting θ1 is applied to the phase shifter 8. Correspondingly, panel device 1 can be controlled to retroreflect the incoming RF signal from D2 by applying a phase setting θ2 to the phase shifter 8 in a static second retroreflection state RR2. This will be discussed in further detail below. Figure 3B The remaining static states are listed below.

[0045] Figure 5A This is a first schematic example of an electronic circuit for automatic phase alignment of analog signals from different antennas. The upper antenna serves as a reference antenna 6'. Analog multipliers (mixers) 9 are arranged in each antenna element to multiply the analog reference signal REF of the reference antenna 6' with the analog antenna signals AS1, ..., ASn of the antenna 6 in the corresponding antenna element. A phase controller 22 is arranged to receive the analog output signal of the multiplier 9 and adjust the phase shifter 8 to optimize (e.g., maximize or minimize) the amplitude (e.g., power) of the analog output signal or the analog signal derived therefrom. Figure 2C The analog multiplier 9 corresponds to or is included in the phase comparator 21. It can be noted that... Figure 5A AS1, ..., ASn in the above can represent the first analog antenna signal or the second analog antenna signal.

[0046] Figure 5B This is a second schematic example of the electronic circuitry for the antenna element. The same bandpass filter 13 (BPF) is arranged to transmit an analog reference signal REF and a corresponding analog antenna signal ( ) within a defined frequency band. Figure 5B(ASn in the original text). Combiner 14 is arranged to receive the input signal from bandpass filter 13. In the first example, combiner 14 is an analog multiplier or mixer, and low-pass filter 15 is arranged to extract the DC component from the output signal of mixer 14. The DC component represents the phase difference between the input signals of mixer 14. The circuit shown is then used to optimize (e.g., maximize or minimize) the DC component, and sample-and-hold device 16 is arranged to hold the optimized DC component. In the second example, combiner 14 is an analog adder, and one of the input signals of the adder is inverted (phase shifted by 180 degrees) such that the adder outputs an analog differential signal representing the difference between the input signals. Power detector 15 is arranged to measure the power of the differential signal. Power represents the phase difference between the input signals of adder 14. The circuit shown is then used to minimize the power, and sample-and-hold device 16 is arranged to hold the minimized power value. One advantage of the second example over the first example is that the second example uses the full bandwidth of the input signal of combiner 14. In the first example, the mixed-down DC component is isolated, which results in the loss of power components that are not mixed into the DC.

[0047] Including more than one panel device in a system used for reflecting RF signals can be advantageous. This allows panel devices to be manufactured in manageable sizes and combined to span larger surface areas, such as covering a wall or ceiling or a portion thereof. Ideal structural features of the respective panel devices may include: ease of attachment to adjacent panel devices, provision of electronic and / or optical connections for the transmission of control data with adjacent panel devices, and the ability to be powered by electricity from adjacent panel devices.

[0048] Figure 6A A system comprising a primary panel device or main panel device 1 and a secondary panel device or slave panel device 1' is illustrated in a side view. In the example shown, panel devices 1 and 1' operate coherently to reflect RF signals between D1 and D2. Coherent operation means that RF signals reflected by the different panel devices 1 and 1' are coherently received at D1 and D2, respectively. Figure 6B This is a perspective view of a system of eight panel devices arranged side-by-side on a wall and operating coherently to reflect RF signals between D1 and D2 using beamforming. Beamforming is... Figure 6B as well as Figure 6D , Figure 6E and Figure 7B The corresponding lobes are schematically represented in the diagram. Those skilled in the art will understand that the lobes are a simplification and that beamforming can have any shape and can involve reflected signal components.

[0049] Figure 6CThis is a side view of two adjacent panel devices 1, 1', illustrating their internal components. Panel devices 1, 1' are structurally identical and include components as shown in the reference. Figure 2A The description includes multiple antenna elements 2, a processor 4, and a memory 5. The corresponding panel devices 1 and 1' also include at least two signal interfaces 30A (electrical and / or optical) and at least two power interfaces 30B (electrical). Interfaces 30A and 30B may be located on at least two sides of the corresponding panel. In the corresponding control panel, the signal interface 30A is connected to the processor 4 and configured to enable the transfer of control data CD between the processors 4 in the panel devices 1 and 1'. The control data CD may be analog or digital. In the corresponding control panel, the power interface 30B is connected to a power management unit (PMU) 32 and configured to connect to a power source (e.g., mains power) and to a power interface 30B on another panel device to transmit power. In one embodiment, the PMU 32 is capable of switching between a power supply mode and a power transmission mode.

[0050] Back Figure 6B The installer mounts the panel devices on the wall in a continuous manner. Each panel device is connected to an adjacent panel device via interfaces 30A and 30B, which in this example are located on all four sides of the panel device. The selected panel device is connected to a power source (not shown), and all other panel devices are powered through power transmission from the selected panel device through all other panel devices. The PMU 32 of the selected panel device is set to power supply mode, while the PMU 32 of the other panel devices is set to power transmission mode.

[0051] In order to achieve coherent operation of panel devices 1 and 1' in the system (e.g., ... Figures 6A to 6B The reflection between D1 and D2 shown can be performed by each of panel devices 1 and 1'. Figure 3A and Figure 3B The method described above is used to determine the combined phase setting of its antenna elements. Each panel device 1, 1' can determine its combined phase setting relative to its reference antenna 6'. Typically, the relative positions of panel devices 1, 1' and the relative positions of reference antenna 6' are not known precisely enough. To ensure coherent operation of all panel devices 1, 1', the corresponding slave panel device 1' can apply phase correction data to adjust its combined phase setting. The phase correction data can be determined during the initial calibration process, which may involve measuring the time delay between the received RF signals by the reference antenna 6' in the system. The phase correction data can be stored in the corresponding slave panel device 1 or transmitted from the master panel device 1 to the corresponding slave panel device 1' as control data CD. Return Figure 3BIn the state of the antenna unit 2, the main panel device 1 can be set to static state R12, and the corresponding slave panel device 1' can be set to static slave state R12*, wherein the corresponding slave panel device 1' applies its combined phase setting adjusted by phase correction data to the phase shifter 8 in the antenna unit 2. Figure 2C ).

[0052] In order to achieve coherent operation of retroreflection to D1 (or D2) of panel devices 1 and 1', the main panel device 1 can be set to a static state RR1 (or RR2), and the corresponding slave panel device 1' can be set to a static slave state RR1* (or RR2*), wherein the corresponding slave panel device 1' applies its first (or second) phase setting adjusted by phase correction data to the phase shifter 8 in the antenna unit 2.

[0053] In one example, the phase correction data is the phase value. It is specific to the corresponding slave panel device 1'. The phase setting θ1 determined for state RR1 can be adjusted in state RR1*. The phase setting θ2 determined for state RR2 can be adjusted to the following under state RR1*: Furthermore, the combined phase setting (θ1+θ2) / 2 determined for state R12 can be adjusted to (θ1+θ2) / under state R12*.

[0054] In another embodiment, an analog reference signal from the reference antenna 6' in the main panel device 1 is transmitted as control data CD to the corresponding slave panel 1', which can perform... Figure 3A and Figure 3B The method described above is used to determine the phase setting associated with the analog reference signal. The corresponding slave panel 1' can then apply the obtained phase setting in one or more of the static slave states R12*, RR1*, and RR2*.

[0055] In some implementations, the main panel device 1 can control the corresponding slave panel device 1' to enter a specific state by providing corresponding control data CD to the corresponding slave panel device 1'. For example, the specific state could be... Figure 3B Any static and adaptive states listed in the table.

[0056] In some implementations, a master panel device 1 can be dynamically selected from among the panel devices in the system or from a group of panel devices (below). For example, each panel device in the system can calculate the current value of a selection parameter and distribute that current value among other panel devices (e.g., as control data CD), so that one panel device can select itself as the master panel device 1 based on the current values ​​of all panel devices. Other panel devices can automatically set themselves as slave panel device 1'.

[0057] In some implementations, a subset of the panel devices in the system are operated coherently. Figure 6D An example is shown in the 3D diagram, in which a group 1A of four panel devices is coherently operated to reflect RF signals between D1 and D2.

[0058] In some implementations, a group of panel devices to be coherently operated is selected based on signal quality parameters of the incoming RF signals from D1 and / or D2 at the respective panel devices in the system. For example, each panel device in the system can determine the current value of the signal quality parameter and compare it to a quality threshold. If the current value exceeds the quality threshold, the panel device can signal to other panel devices via control data CD that it will be included in the group. Therefore, the panel device can automatically assign itself to reflect incoming RF signals. The signal quality parameters can be calculated for one or more aggregated antenna signals generated by summing the phase-aligned antenna signals in all antenna elements of the respective panel device. The corresponding aggregated analog signal is an analog representation of the RF signal from D1 or D2. For example, the signal quality parameters can represent amplitude, entropy, power, SNR, array gain, etc. These implementations will allow the remaining panel devices outside the group to be deactivated or operated for reflecting RF signals between another pair of communication devices (see [link to implementation]). Figure 6E ).

[0059] In some implementations, panel devices within a system or group can be dynamically assigned unique identifiers (IDs) for each individual panel device within the system or group. Therefore, the control data CD may include IDs of one or more destination control panels, and optionally include the ID of the originating control panel. Panel devices can be configured to route control data CDs within the system to destination panel devices based on the included IDs.

[0060] In some implementations, different panel devices or subgroups of panel devices in the system can be operated to reflect RF signals associated with different communication devices. Figure 6EAn example is shown in the 3D diagram, where four panel devices in corresponding subsets 1B and 1C are coherently operated to reflect RF signals between D1 and D2 and between D1 and D3, respectively. The panel devices can assign themselves to groups based on the current values ​​of the aforementioned signal quality parameters of the incoming RF signals from different communication devices. For example, the panel devices in subset 1B may have larger current values ​​for RF signals from D1 and D2 than for RF signals from D1 and D3, while the opposite is true for the panel devices in subset 1C.

[0061] In some implementations, the RF signal can be received by a first panel device or group of panel devices using beamforming and retransmitted by a second panel device or group of panel devices using beamforming. Thus, the system is operated as if the first panel device and the second panel device or group were a single panel device.

[0062] exist Figure 7A An example is shown in the side view, where the main panel device 1 receives RF signals and retransmits RF signals via another slave panel device 1' spaced apart from the main panel device 1. Figure 7B Another example is shown in the perspective view, where panel device 1D uses beamforming to receive an RF signal from D2 and panel device 1E uses beamforming to retransmit the RF signal to D1. For example, it can be envisioned that the received signal of panel device 1D, which is closest to D2, is much stronger than that of other panel devices. However, panel device 1D may be far from D1, resulting in a weaker link between panel device 1D and D1. In such an example, it may be advantageous to receive the RF signal from D2 via panel device 1D and retransmit the RF signal from panel device 1E, which is closest to D1. In some implementations, this functionality is achieved by setting panel device 1D to a static receive state RX2 and panel device 1E to a static transmit state TX1. Figure 3B This is achieved through [method 1D]. In state RX2, panel device 1D applies RX2 phase setting to phase-align the analog antenna signals in its antenna element 2 and coherently combines the antenna signals into the aforementioned aggregated antenna signal. Thus, panel device 1D receives RF signals using beamforming associated with D2. Panel device 1D then transmits the aggregated antenna signal as control data CD to panel device 1E (via any intermediate panel device, see [link]). Figures 7A to 7B It can be noted that the aggregated antenna signal, as an analog signal, can be transmitted in either analog or digital format. In state TX1, panel device 1E receives the aggregated antenna signal and transfers a portion of the received analog signal to the individual antenna elements 2 in antenna elements 2 of panel device 1. Antenna elements 2 apply the TX1 phase setting to transmit RF signals using beamforming associated with D1.

[0063] In some implementations, the phase settings of RX2 and TX1 can be determined based on the phase settings of one or more other static states of the respective panel device. Returning to the above non-limiting example where static states RR1 and RR2 are associated with phase settings θ1 and θ2 respectively, the phase settings of states TX1 and RX2 can be given by θ1 / 2 and θ2 / 2 respectively.

[0064] Similarly, the panel device can obtain: static receiver state RX1 ( Figure 3B Its application enables panel devices to receive RF signals and generate aggregated antenna signals using beamforming associated with D1; and static transmitter state TX2 ( Figure 3B This allows panel devices to transmit RF signals using beamforming related to D2 based on aggregated antenna signals. For example, the phase settings for states RX1 and TX2 can be given by θ1 / 2 and θ2 / 2, respectively.

[0065] The implementation method of spatially separated RF signal reception and transmission is also applicable to panel device groups. To ensure coherent operation within a receiving panel device group, the master panel device of the group can be set to state RX1 (or RX2), and the corresponding slave panel device of the group can be set to slave state RX1* (or RX2*). Similarly, for slave states RR1*, RR2*, and R12*, the phase settings of RX1* and RX2* adjusted by phase correction data can be applied to the phase shifter 8 in antenna element 2. Alternatively, the phase settings of slave states RX1* and RX2* can be calculated based on the phase settings of slave states RR1* and RR2*. Likewise, slave panel devices within a transmitting panel device group can be set to slave state TX1* (or TX2*), which allows the phase settings of TX1 (or TX2) adjusted by phase correction data to be applied to the phase shifter 8 in antenna element 2. Alternatively, the phase settings of slave states TX1* and TX2* can be calculated based on the phase settings of slave states RR1* and RR2*.

[0066] Figure 8 An embodiment of antenna element 2 is illustrated, which enables spatially separated reception and transmission of RF signals. The following description will focus on... Figure 2CThe implementation differs from the previous one. Antenna unit 2 includes a switch 23, which is arranged between phase shifter 8 and RF reflector 7 and configured to obtain any of three switching states RR, TX, and RX. Switch 23 can be set to a switching state based on control signal C2 from processor 4. Switching state RR electrically connects antenna 6 to RF reflector 7 and causes antenna unit 2 to reflect incoming RF signals. Switching state TX electrically connects antenna 6 to input device 24, which is configured to receive incoming aggregated antenna signal AAS and distribute it to antenna unit 2 of panel device. Switching state TX causes antenna unit 2 to direct analog signals to antenna 6 for transmission. Switching state RX electrically connects antenna 6 to output device 25, which is configured to receive and combine antenna signals from antenna unit 2 of panel device. Switching state RX causes antenna unit 2 to receive incoming RF signals, preferably without reflection.

[0067] Back Figure 3B The panel device can also be configured to obtain a static state OFF, wherein the phase controller 22 can apply a predefined phase setting that effectively randomizes the phase between the antenna elements 2 in the panel device. This prevents the panel device from being unintentionally configured to reflect incoming RF signals using beamforming, which could interfere with the operation of communication devices within range. In an alternative embodiment, the static state OFF may involve setting switch 23 to a switch state configured to disable the ability of antenna elements 2 to reflect incoming RF signals.

[0068] Reference Figure 9 Further examples illustrate some of the implementation methods described above. Figure 9 The example illustrates signaling within a system comprising a master panel device 1 and a slave panel device 1'. The example shown is mapped to... Figure 3A and Figure 3BThe steps in the process also include some additional steps. Each panel device 1, 1' receives an RF signal from D1 (step 301). The main panel device 1 transmits the analog antenna reference signal REF to the slave panel device 1' (step 301A). The main panel device 1 determines the phase setting of its state RR1 (step 302), and the corresponding slave panel device 1' determines the phase setting of its state RR1* (step 302). The panel devices 1, 1' store their phase settings (step 303). The corresponding slave device 1' determines the current value Qi_D1 of the signal quality parameter of D1 and transmits the current value to the main panel device 1 that stores the current value (step 303B). Then, each panel device 1, 1' receives the RF signal from D2 (step 304). The main panel device 1 transmits the analog antenna reference signal REF to the slave panel device 1' (step 304A). The main panel device 1 determines the phase setting of its state RR2 (step 305), and the corresponding slave panel device 1' determines the phase setting of its state RR2* (step 305). Panel devices 1, 1' store their phase settings (step 306). The corresponding slave device 1' determines the current value Qi_D2 of the signal quality parameter of D2 and transmits this current value to the main panel device 1 (step 306B). It evaluates the current values ​​Qi_D1 and Qi_D2 and determines the corresponding static state of the corresponding panel device 1, 1' (step 306C). The main panel device 1 transmits the selected state to the corresponding slave device 1' (step 306D), thereby obtaining and applying the phase setting of its assigned static state (step 307A). The main panel device 1 also acquires and applies the phase setting of its assigned static state (step 307A). For example, step 307A may cause the system to be configured to correspond to... Figure 6B , Figure 6D , Figure 6E and Figure 7B Any one of them.

[0069] The preceding description assumes that the first adaptive state R1 and the second adaptive state R2 are obtained sequentially by the system used to determine the phase settings relating to both D1 and D2. However, it is conceivable that the second adaptive state R2 may be omitted or performed well before the first adaptive state R1, for example, if it is known that D2 is stationary with respect to the system. In an alternative, a predefined codebook of phase settings relating to D2 may be stored by a corresponding panel device in the system.

[0070] Although the foregoing embodiments have been described for systems comprising aggregated physically separate panel devices, these embodiments are equally applicable to systems consisting of a single panel device. Figure 6D Similarly, a subset 1A of the antenna elements in the panel device can be configured to receive and reflect RF signals using beamforming between two communication devices. Figure 6ESimilarly, different subsets 1B and 1C of the antenna elements in the panel device can be configured to receive and reflect RF signals between different communication device pairs using beamforming. Figure 7B Similarly, different subsets 1D and 1E of the antenna elements in the panel device can be configured to receive and reflect RF signals separately between two communication devices using beamforming.

[0071] While the subject matter of this disclosure has been described in conjunction with embodiments that are currently considered to be the most practical and preferred, it should be understood that the subject matter is not limited to the disclosed embodiments, but rather is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims.

[0072] Furthermore, although the operations are depicted in a specific order in the accompanying drawings, this should not be construed as requiring that such operations be performed in the specific order shown or in sequential order, or that all of the shown operations be performed to obtain the desired result. In some cases, parallel processing may be advantageous.

[0073] The following sections set forth terms to summarize some of the aspects and implementation methods disclosed above.

[0074] Clause 1. A system for reflecting RF signals, the system comprising:

[0075] Multiple antenna elements (2) are configured to receive and passively reflect the RF signal, wherein each antenna element (2) includes a corresponding phase shifter (8) which is operationally configured to adjustably apply a phase change to the RF signal before the RF signal is reflected.

[0076] Reference antenna (6'); and

[0077] A control system (1A, 20) that communicates with the reference antenna (6') and the corresponding phase shifter (8), the control system (1A, 20) being configured to:

[0078] The corresponding phase shifter (8) is operated to phase-align the first analog antenna signal received by the corresponding antenna unit (2) in response to the first RF signal from the first device (D1) with the first analog reference signal (REF) received by the reference antenna (6') in response to the first RF signal.

[0079] For the corresponding phase shifter (8), a first phase setting corresponding to the phase of the corresponding phase shifter (8) is determined when the first analog antenna signal is phase-aligned with the first analog reference signal (REF); and

[0080] Store the first phase setting.

[0081] Clause 2. The system according to Clause 1, wherein the control system (1A, 20) is further configured to: generate a product or sum of a first input signal corresponding to the first analog antenna signal and a reference input signal corresponding to the first analog reference signal (REF), and adjust the phase of the corresponding phase shifter (8) until the product or the sum satisfies a predefined criterion, wherein the first phase setting corresponds to the phase of the corresponding phase shifter (8) when the product or the sum satisfies the predefined criterion.

[0082] Clause 3. The system according to Clause 1 or 2, wherein the respective antenna unit (2) includes an antenna (6), an RF reflective element (7) configured to reflect the first analog antenna signal, and a conductive path extending from the antenna (6) to the RF reflective element (7).

[0083] Clause 4. The system according to Clause 3, wherein the respective phase shifter (8) is arranged in the conductive path between the antenna (6) and the RF reflector (7).

[0084] Clause 5. The system according to Clause 4, wherein the respective antenna unit (2) further includes a switch (23) arranged in the conductive path between the respective phase shifter (8) and the RF reflector (7), wherein the switch (23) is operable by the control system (1A, 20) to obtain a first switch state (RR), in which the switch (23) electrically connects the phase shifter (8) to the RF reflector (7), and also obtains at least one of a second switch state (TX) and a third switch state (RX), wherein the switch (23) in the second switch state (TX) connects the phase shifter (8) to a first device (24) configured to supply an analog input signal, and wherein the switch (23) in the third switch state (RX) connects the phase shifter (8) to a second device (25) configured to combine analog signals into a converged signal.

[0085] Clause 6. The system according to any one of the preceding clauses, wherein the first phase setting corresponds to the time delay applied by the phase shifter (8) to the first analog antenna signal.

[0086] Clause 7. The system according to any one of the preceding clauses, wherein the control system (1A, 20) is further configured to: operate the respective phase shifter (8) to phase-align a second analog antenna signal received by the respective antenna unit (2) in response to a second RF signal from the second device (D2) with a second analog reference signal (REF) received by the reference antenna (6') in response to the second RF signal; determine, for the respective phase shifter (8), a second phase setting corresponding to the phase of the respective phase shifter (8) when the second analog antenna signal (AS1, ..., ASn) is phase-aligned with the second analog reference signal (REF); and store the second phase setting or a combined phase setting corresponding to a combination of the first phase setting and the second phase setting.

[0087] Clause 8. The system according to Clause 7, wherein the control system (1A, 20) is further configured to apply the combined phase setting to the respective phase shifter (8) in the first group (1A, 1B, 1C) antenna elements (2) of the plurality of antenna elements (2), thereby configuring the group (1A, 1B, 1C) antenna elements to reflect incoming RF signals from the first device (D1) to the second device (D2), or from the second device (D2) to the first device (D1).

[0088] Clause 9. The system according to any one of Clauses 1 to 7, wherein the control system (1A, 20) is further configured to: generate a converged antenna signal (AAS) by coherently combining a third analog antenna signal received by an antenna element (2) in a first group (1D) of the plurality of antenna elements (2) in response to an incoming RF signal from the first device (D1); provide the converged antenna signal (AAS) to an antenna element (2) in a second group (1E) of the plurality of antenna elements (2); and operate the antenna element (2) in the second group (1E) to transmit the incoming RF signal.

[0089] Clause 10. The system according to Clause 9, wherein the first group (1D) and the second group (1E) do not overlap.

[0090] Clause 11. The system according to Clause 9 or 10, wherein the control system (1A, 20) is configured to: calculate a third phase setting for the corresponding phase shifter (8) in the first group (1D) antenna elements (2) according to the first phase setting; apply the third phase setting to the corresponding phase shifter (8) in the first subset (1D) to phase align the third analog signal; and combine the phase-aligned third analog signal to generate the aggregated antenna signal (AAS).

[0091] Clause 12. The system according to any one of Clauses 8 to 11, wherein the control system (1A, 20) is configured to: determine signal quality data at the plurality of antenna elements (2) and define at least one of the first group and the second group (1A-1E) based on the signal quality data.

[0092] Clause 13. The system according to any one of Clauses 8 to 12, wherein the first group of antenna elements (2) and the second group of antenna elements (2) are arranged on separate panel devices (1, 1').

[0093] Clause 14. The system according to any one of the preceding clauses, the system comprising panel devices (1, 1'), the panel devices (1, 1') comprising a corresponding subset of the plurality of antenna elements (2), wherein the control system (1A, 20) is configured to coordinate the operation of the panel devices (1, 1').

[0094] Clause 15. A panel device comprising: a housing; and a system according to any one of Clauses 1 to 12, wherein the housing includes a support (3) for the plurality of antenna elements (2) and the reference antenna (6').

[0095] Clause 16. The panel device according to Clause 15, the panel device including a signal interface (30A) for connection to another panel device (1') including a system according to any one of Clauses 1 to 12, wherein the control system (1A, 20) of the panel device is configured to exchange control data (CD) with the other panel device (1') via the signal interface (30A).

[0096] Clause 17. The panel device according to Clause 16, wherein the control system (1A, 20) is configured to send the control data (CD) to set the operating state of the additional panel device (1'), the operating state causing the additional panel device (1') to apply a dedicated phase setting to the corresponding phase shifter (8) in the plurality of antenna elements (2) in the additional panel device (1').

[0097] Clause 18. The panel device according to Clause 16 or 17, wherein the control data (CD) includes reference phase data (REF), and the additional panel device (1') is phase-aligned with the first analog antenna signal in the antenna unit (2) of the additional panel device (1') based on the reference phase data (REF).

[0098] Clause 19. The panel device according to any one of Clauses 16 to 18, the panel device further comprising a power interface (30B) for supplying power to and / or receiving power from the additional panel device (1').

[0099] Clause 20. A method for a system for reflecting an RF signal, the system comprising a plurality of antenna elements (2) and a reference antenna (6'), the plurality of antenna elements (2) being configured to receive and passively reflect the RF signal, wherein each antenna element (2) includes a corresponding phase shifter (8) operationally configured to adjustably apply a phase change to the RF signal before it is reflected, the method comprising the steps of:

[0100] The corresponding phase shifter (8) is operated (301) to phase-align the first analog antenna signal received by the corresponding antenna unit (2) in response to the first RF signal from the first device (D1) with the first analog reference signal (REF) received by the reference antenna (6') in response to the first RF signal.

[0101] For the corresponding phase shifter (8), determine (302) a first phase setting corresponding to the phase of the corresponding phase shifter (8) when the first analog antenna signal is phase-aligned with the first analog reference signal (REF); and

[0102] Store (303) the first phase setting.

[0103] Clause 21. The method according to Clause 20, wherein the step of determining (302) comprises: generating a product or sum of a first input signal corresponding to the first analog antenna signal and a reference input signal corresponding to the first analog reference signal (REF), and adjusting the phase of the corresponding phase shifter (8) until the product or the sum satisfies a predefined criterion, wherein the first phase setting corresponds to the phase of the corresponding phase shifter (8) when the product or the sum satisfies the predefined criterion.

[0104] Clause 22. The method according to Clause 20 or 21, the method further comprising the steps of: operating (304) the respective phase shifter (8) to phase-align a second analog antenna signal received by the respective antenna unit (2) in response to a second RF signal from the second device (D2) with a second analog reference signal (REF) received by the reference antenna (6') in response to the second RF signal; determining (305) for the respective phase shifter (8) a second phase setting corresponding to the phase of the respective phase shifter (8) when the second analog antenna signal is phase-aligned with the second analog reference signal (REF); and storing (306) the second phase setting or a combined phase setting corresponding to a combination of the first phase setting and the second phase setting.

[0105] Clause 23. The method according to Clause 22, the method further comprising the step of: applying the combined phase setting (307) to the corresponding phase shifter (8) in the first group (1A, 1B, 1C) antenna elements (2) of the plurality of antenna elements (2), thereby configuring the group (1A, 1B, 1C) antenna elements to reflect an incoming RF signal from the first device (D1) to the second device (D2), or from the second device (D2) to the first device (D1).

[0106] Clause 24. A computer-readable medium comprising computer instructions that, when executed by a processor (4), cause the processor (4) to perform the method according to any one of Clauses 20 to 23.

Claims

1. A system for reflecting RF signals, the system comprising: a plurality of antenna elements (2) configured to receive and passively reflect the RF signals, wherein each antenna element of the plurality of antenna elements (2) comprises an antenna (6) and a respective phase shifter (8) operatively used to adjustably impose a phase change on the RF signals before the RF signals are reflected, a reference antenna (6’), and a control system (1A, 20) in communication with the reference antenna (6’) and the respective phase shifters (8), the control system (1A, 20) being configured to: operate on the respective phase shifters (8) to phase align a first analog antenna signal (AS1,..., ASn) received by the antenna (6) in the respective antenna element of the plurality of antenna elements (2) in response to a first RF signal from a first device (D1) with a first analog reference signal (REF) received by the reference antenna (6’) in response to the first RF signal, determine, for the respective phase shifters (8), a first phase setting corresponding to a phase of the respective phase shifter (8) when the first analog antenna signal (AS1,..., ASn) is phase aligned with the first analog reference signal (REF), and store the first phase setting, wherein each antenna element of the plurality of antenna elements (2) comprises an RF reflecting element (7) configured to reflect the first analog antenna signal (AS1,..., ASn) and a conductive path extending from the antenna (6) to the RF reflecting element (7), wherein the respective phase shifter (8) is arranged in the conductive path intermediate the antenna (6) and the RF reflecting element (7), and wherein the control system (1A, 20) is further configured to generate a product or a sum of a first input signal corresponding to the first analog antenna signal (AS1,..., ASn) and a reference input signal corresponding to the first analog reference signal (REF) and to adjust a phase of the respective phase shifter (8) until the product or the sum satisfies a predefined criterion, wherein the first phase setting corresponds to the phase of the respective phase shifter (8) when the product or the sum satisfies the predefined criterion.

2. The system of claim 1, wherein, The individual one of the plurality of antenna elements (2) further comprises a switch (23) arranged in the conductive path intermediate the respective phase shifter (8) and the RF reflective element (7), wherein the switch (23) is operable by the control system (1A, 20) for obtaining a first switch state (RR) in which the switch (23) electrically connects the phase shifter (8) to the RF reflective element (7), and at least one of a second switch state (TX) and a third switch state (RX), wherein the switch (23) in the second switch state (TX) connects the phase shifter (8) to a first device (24) configured to supply an analog input signal, and wherein the switch (23) in the third switch state (RX) connects the phase shifter (8) to a second device (25) configured to combine analog signals into an aggregated signal.

3. The system of claim 1, wherein, The first phase setting corresponds to a time delay imposed by the phase shifter (8) on the first analog antenna signal.

4. The system of claim 1, wherein, The control system (1A, 20) is further configured to: operate the respective phase shifter (8) to phase align a second analog antenna signal (AS1,..., ASn) received by the individual one of the plurality of antenna elements (2) in response to a second RF signal from a second device (D2) with a second analog reference signal (REF) received by the reference antenna (6') in response to the second RF signal, determine, for the respective phase shifter (8), a second phase setting corresponding to a phase of the respective phase shifter (8) when the second analog antenna signal (AS1,..., ASn) is phase aligned with the first analog reference signal (REF), and store the second phase setting or a combined phase setting corresponding to a combination of the first phase setting and the second phase setting.

5. The system of claim 4, wherein, The control system (1A, 20) is further configured to apply the combined phase setting to the respective phase shifter (8) in a first group of antenna elements of the plurality of antenna elements (2), thereby configuring the first group of antenna elements to reflect an incoming RF signal from the first device (D1) to the second device (D2) or from the second device (D2) to the first device (D1).

6. The system of any one of claims 1 to 4, wherein, The control system (1A, 20) is further configured to generate an aggregated antenna signal (AAS) by coherently combining third analog antenna signals received by antenna elements in a first group of antenna elements of the plurality of antenna elements (2) in response to an incoming RF signal from the first device (D1), provide the aggregated antenna signal (AAS) to antenna elements in a second group of antenna elements of the plurality of antenna elements (2), and operate the antenna elements in the second group of antenna elements to transmit the incoming RF signal.

7. The system of claim 6, wherein, The first and second groups of antenna elements are non-overlapping.

8. The system of claim 6, wherein, The control system (1A, 20) is configured to calculate, from the first phase setting, third phase settings for the respective phase shifters (8) in the first group of antenna elements; apply the third phase settings to the respective phase shifters (8) in the first group of antenna elements for phase aligning the third analog antenna signals; and combine the phase aligned third analog antenna signals to generate the aggregated antenna signal (AAS).

9. The system of claim 6, wherein, The control system (1A, 20) is configured to determine signal quality data at the plurality of antenna elements (2) and to define at least one of the first and second groups of antenna elements from the signal quality data.

10. The system of claim 6, wherein, The first and second groups of antenna elements are arranged on separate panel devices (1, 1’).

11. The system of claim 1, comprising a panel device (1, 1') comprising a respective subset of the plurality of antenna elements (2), wherein, The control system (1A, 20) is configured to coordinate operation of the panel devices (1, 1’).

12. The system of claim 1, wherein, The individual ones of the plurality of antenna elements (2) comprise a phase comparator (21) configured to generate the product or sum of the first input signal and the reference input signal and a phase controller (22) configured to adjust the phase of the respective phase shifter (8) until the product or sum satisfies a predefined criterion.

13. The system of claim 12, wherein, A coupler or switch (8A) is arranged in a conductive path between the respective phase shifter (8) and the RF reflecting element (7) to divert power flowing in one direction in the conductive path towards or away from the RF reflecting element (7) to the phase comparator (21), the power being diverted by the coupler or switch (8A) to form the first input signal.

14. A panel device comprising a housing and the system of claim 1, wherein, The housing comprises a support (3) for the plurality of antenna elements (2) and the reference antenna (6’).

15. Panel device according to claim 14, comprising a signal interface (30A) for connecting to a further panel device (1') comprising a system according to claim 1, wherein, The control system (1A, 20) of the panel device is configured to exchange control data (CD) with the further panel device (1’) over the signal interface (30A).

16. The panel apparatus of claim 15, wherein, The control system (1A, 20) is configured to send the control data (CD) to set an operating state of the further panel device (1’), the operating state causing the further panel device (1’) to apply dedicated phase settings to the respective phase shifters (8) in the plurality of antenna elements (2) in the further panel device (1’).

17. The panel apparatus of claim 15, wherein, The control data (CD) comprises reference phase data (REF) and is based on the reference phase data (REF) to cause the further panel device (1') to phase align the first analog antenna signal (AS1,..., ASn) in each of the plurality of antenna elements (2) of the further panel device (1') with the first analog antenna signal (AS1,..., ASn) in the respective one of the plurality of antenna elements (2) of the panel device.

18. The panel device of claim 15, further comprising a power interface (30B) for supplying and / or receiving power to / from the further panel device (1').

19. A method of operating a system according to any one of claims 1 to 13, the method comprising the steps of: operating (301) a respective phase shifter (8) to phase align a first analog antenna signal received by a plurality of antenna elements (2) in response to a first RF signal from a first device (D1) with a first analog reference signal (REF) received by a reference antenna (6') in response to the first RF signal; determining (302), for the respective phase shifter (8), a first phase setting corresponding to a phase of the respective phase shifter (8) when the first analog antenna signal is phase aligned with the first analog reference signal (REF); and storing (303) the first phase setting.

20. The method of claim 19, wherein, The step of determining (302) comprises generating a product or a sum of a first input signal corresponding to the first analog antenna signal and a reference input signal corresponding to the first analog reference signal (REF) and adjusting a phase of the respective phase shifter (8) until the product or the sum satisfies a predefined criterion, wherein the first phase setting corresponds to the phase of the respective phase shifter (8) when the product or the sum satisfies the predefined criterion.

21. The method of claim 19, further comprising the step of: operating (304) the respective phase shifter (8) to phase align a second analog antenna signal received by the plurality of antenna elements (2) in response to a second RF signal from a second device (D2) with a second analog reference signal (REF) received by the reference antenna (6') in response to the second RF signal; determining (305), for the respective phase shifter (8), a second phase setting corresponding to a phase of the respective phase shifter (8) when the second analog antenna signal is phase aligned with the second analog reference signal (REF); and storing (306) the second phase setting or a combined phase setting corresponding to a combination of the first phase setting and the second phase setting.

22. The method of claim 21, further comprising the step of: applying (307) the combined phase setting to the respective phase shifters (8) in a first set of antenna elements in the plurality of antenna elements (2), thereby configuring the first set of antenna elements to reflect an incoming RF signal from the first device (Dl) to the second device (D2), or from the second device (D2) to the first device (Dl).

23. A computer readable medium comprising computer instructions which, when executed by a processor (4), cause the processor (4) to perform the method according to claim 19.

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