WO2023052335A1

WO2023052335A1 - Coverage enhancing device having arrangement

Info

Publication number: WO2023052335A1
Application number: PCT/EP2022/076782
Authority: WO
Inventors: Fredrik RUSEK; Erik Lennart Bengtsson; Olof Zander; Kun Zhao; Jose Flordelis; Chaitanya TUMULA; Zhinong Ying
Original assignee: Sony Group Corporation; Sony Europe B.V.
Priority date: 2021-09-29
Filing date: 2022-09-27
Publication date: 2023-04-06

Abstract

Disclosed herein are examples of a coverage enhancing device comprising a first antenna input configured to receive a first signal, a second antenna input configured to receive a second signal, a first antenna output configured to output the first signal, a second antenna output configured to output the second signal, wherein a relative arrangement of the first antenna input and the first antenna output is different from a relative arrangement of the second antenna input and the second antenna output.

Description

COVERAGE ENHANCING DEVICE HAVING ARRANGEMENT

TECHNICAL FIELD

The present disclosure pertains generally to the field of wireless communications. The present disclosure relates to coverage enhancing devices and methods of operation.

BACKGROUND

Coverage enhancing devices can be used for beamforming, such as to or from a base station. Coverage enhancing devices can be used to improve signal coverage, for example at hard-to-reach locations, or transitions from outdoors to indoors. Certain coverage enhancing devices can be reconfigurable, such as having the ability to choose a phase shift per coverage enhancing device antenna. For given incoming and outgoing angles, an optimal phase setting can be obtained. However, a significant problem is that such phase setting is not limited to reflecting the designed-for incoming and outgoing signal directions, but is in fact reflecting a wide range of other directional pairs with the same beamforming gain as for the designed-for incoming and outgoing signal directions. This is because, in general, any input angle has an associated output angle for a specific configuration. This may lead to associated issues, such as signal interference.

SUMMARY

Accordingly, there is a need for coverage enhancing devices that reduce unwanted signal reflections and/or transmissions, which can improve interference levels.

There is a need for coverage enhancing devices and related methods which may mitigate, alleviate, or address the existing shortcomings, for example by reducing unwanted signal reflections and/or transmissions.

Disclosed herein is an example of a coverage enhancing device. The coverage enhancing device comprises a first antenna input. The first antenna input is configured to receive a first signal. The coverage enhancing device comprises a second antenna input. The second antenna input is configured to receive a second signal. The coverage enhancing device comprises a first antenna output. The first antenna output is configured to output the first signal. The coverage enhancing device comprises a second antenna output. The second antenna output is configured to output the second signal. A relative arrangement of the first antenna input and the first antenna output is different from a relative arrangement of the second antenna input and the second antenna output.

It is an advantage of the present disclosure to provide coverage enhancing devices which reduce interference. For example, the present disclosure can reduce, or eliminate, unwanted signal reflections and/or transmissions from the coverage enhancing device. For example, reflections and/or transmissions not configured for can be reduced and/or eliminated.

Disclosed herein is an example of a coverage enhancing device. The coverage enhancing device comprises a plurality of antennas arranged on the coverage enhancing device. At least some antennas of the plurality of antennas are spaced apart irregularly on the coverage enhancing device. The plurality of antennas is configured to reduce parasitic reflections of the coverage enhancing device.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other features and advantages of the present disclosure will become readily apparent to those skilled in the art by the following detailed description of examples thereof with reference to the attached drawings, in which:

Fig. 1 is a schematic of a coverage enhancing device,

Fig. 2 is a beamforming gain plot of the coverage enhancing device of Fig. 1 ,

Fig. 3 is a schematic of an example coverage enhancing device according to the disclosure,

Fig. 4A is a beamforming gain plot of the example coverage enhancing device according to the disclosure, Fig. 4B is a beamforming gain plot of the example coverage enhancing device according to the disclosure,

Fig. 5A is a combined beamforming gain plot of a coverage enhancing device,

Fig. 5B is a combined beamforming gain plot of the example coverage enhancing device according to the disclosure,

Fig. 6 is a cumulative distribution function of beamforming gain summarizing the combined beamforming gain plots of Fig. 5A- Fig. 5B,

Fig. 7 is a schematic of an example coverage enhancing device according to the disclosure,

Fig. 8 is a schematic of a coverage enhancing device,

Fig. 9 is a schematic of an example coverage enhancing device according to the disclosure,

Fig. 10 is a schematic of an example coverage enhancing device according to the disclosure,

Fig. 11 is a schematic of an example system with an example coverage enhancing device according to the disclosure,

Fig. 12 is a beamforming gain plot of the coverage enhancing device of Fig. 10, and

Figs. 13A-13C are schematics of example coverage enhancing devices according to the disclosure.

DETAILED DESCRIPTION

Various examples and details are described hereinafter, with reference to the figures when relevant. It should be noted that the figures may or may not be drawn to scale and that elements of similar structures or functions are represented by like reference numerals throughout the figures. It should also be noted that the figures are only intended to facilitate the description of the examples. They are not intended as an exhaustive description of the disclosure or as a limitation on the scope of the disclosure. In addition, an illustrated example need not have all the aspects or advantages shown. An aspect or an advantage described in conjunction with a particular example is not necessarily limited to that example and can be practiced in any other examples even if not so illustrated, or if not so explicitly described.

Disclosed herein are devices and/or systems for beamforming. Specifically, disclosed herein are coverage enhancing devices and systems. The disclosed coverage enhancing devices can provide for an improved coverage and reduced interference. The coverage enhancing devices can be used for network management. The coverage enhancing devices can be used for beam and/or panel management. The coverage enhancing devices can be used for far-field propagation and/or near-field propagation. The devices can utilize both passive fixed array panels and intelligent surfaces to improve coverage and beamforming of signals.

The disclosed coverage enhancing devices can be one of a number of different types of devices, which can be used interchangeably herein. For example, the coverage enhancing devices can be one or more of reconfigurable intelligent surfaces (RISs), repeater type devices, repeaters, intelligent surfaces, and reconfigurable reflective devices (RRDs). The coverage enhancing devices can have one or more antennas, such as antenna panels, antenna elements, antenna inputs, antenna outputs, and/or unit cells for meta-surfaces. The coverage enhancing devices can have one or more receivers, for example low-power receivers. The coverage enhancing devices can have one or more transmitters, such as an active component that provides amplification to a signal.

As an example coverage enhancing device being a reconfigurable intelligent surface, the reconfigurable intelligence surface may, in certain circumstances though not in all circumstances, be compared to a metal plate, or a mirror, where azimuth and elevation can be tilted. Any input angle will have an associated output angle that depends on how it is tilted. Configuring it can mean that one such input-output angle pair is ensured, while other angle pairs are indirectly set as a result of the configuration of the targeted pair.

In one or more example coverage enhancing devices, the signals disclosed herein can be one or more of: energy, transmission, wave energy, FR1 and FR2 signals, 5G signals, 6G signals, sub-6 GHz, electromagnetic energy, waves, electromagnetic plane waves, electromagnetic signals, plane signals, spherical waves, spherical signals, cylindrical waves, and cylindrical signals. As disclosed herein, waves and signals can be used interchangeably. The particular type of signal is not limiting.

In one or more example systems, the signals can be millimeter waves. In one or more example coverage enhancing devices, the signals can have a wavelength of 10, 9, 8, 7, 6, 5, 4, 3, 2, or 1mm or less. In one or more example systems, the signals can have a wavelength of 10, 9, 8, 7, 6, 5, 4, 3, 2, or 1 mm or greater. In one or more example coverage enhancing devices, the signals can have a wavelength of between 1mm and 10mm. The particular wavelength of the signal is not limiting.

In one or more example coverage enhancing devices, the signals can have a frequency in the range of 1GHz to 100 THz. In one or more example coverage enhancing devices, the signals can have a frequency in the range of 1 MHz to 100 THz, such as 400MHz to 100 THz. In one or more example coverage enhancing devices, the signals can have a frequency of 1 , 2, 3, 4, 5, 6, 7, 8, 9, 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 200, 300, 400, 500, 600, 700, 800, 900, or 1000 GHz or less. In one or more example coverage enhancing devices, the signals can have a frequency of 1 , 2, 3, 4, 5, 6, 7, 8, 9, 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 200, 300, 400, 500, 600, 700, 800, 900, or 1000 GHz or greater. In one or more example coverage enhancing devices, the signals can have a frequency of 1 , 2, 3, 4, 5, 6, 7, 8, 9, 10, 20, 30, 40, 50, 60, 70, 80, 90, or 100 THz or less. In one or more example systems, the signals can have a frequency of 1 , 2, 3, 4, 5, 6, 7, 8, 9, 10, 20, 30, 40, 50, 60, 70, 80, 90, or 100 THz or greater. The particular frequency of the signal is not limiting.

The disclosed coverage enhancing devices can utilize passive components, such as passive fixed array panels, and active components, such as intelligent surfaces. The passive components may be passive or semi-passive components.

Components of the disclosed coverage enhancing devices systems, such as the active components and passive components, can be advantageous to reflect and/or direct and/or redirect signals. For example, the coverage enhancing devices reflect and/or direct and/or redirect an incoming signal from a given incoming direction to a given outgoing direction. As disclosed herein, reflecting and directing can be used interchangeably. Components of the coverage enhancing devices can be used to reflect waves and/or signals, such as in the mm wave spectrum and/or any other wave spectrum. Further, the components of the coverage enhancing devices can be configured to make reflections of signals which appear in-phase in a certain direction and/or area.

As disclosed herein, reflecting can include transmitting, re-radiating, directing, and/or retransmitting a signal. The reflecting may include altering direction, wavefront, and/or polarization of a signal.

The user equipment disclosed herein can be one of many types of electronic devices, for example one or more of: a user device, a computer, a tablet, a wireless device, a server, and a smart phone. The particular electronic device is not limiting.

As discussed herein, a coverage enhancing device, and in particular antennas, such as antenna input(s) and antenna output(s) may have an arrangement, such as a relative arrangement. The arrangement may be, for example, a relative arrangement of antennas, such as antenna input(s) and antenna output(s) on a particular coverage enhancing device. The arrangement may be, for example, a relative arrangement of antennas, such as antenna input(s) and antenna output(s) on a particular array of a coverage enhancing device.

For example, two arrays of a coverage enhancing device, which are at different physical positions in space, such as orthogonal, may have the antennas, such as antenna input(s) connected with respective antenna output(s), having the same relative arrangement. Positions can be relative positions within an arrangement, or a relative arrangement.

A relative arrangement of the first antenna input and the first antenna output may be seen as a relative arrangement in space. A relative arrangement of the first antenna input and the first antenna output may be obtained by a geometric transformation, such as a projection, a translation, and/or a rotation. For example, when the relative arrangement of the first antenna input and the first antenna output is different from a relative arrangement of the second antenna input and the second antenna output, the geometric transformation between a position of the first antenna input and a position of the first antenna output may be different from the geometric transformation between a position of the second antenna input and a position of the second antenna output. A relative position may be seen as a relative position in space, such as a relative distance between a first antenna input and a first antenna output. For example, when the relative position of the first antenna input and the first antenna output is different from a relative position of the second antenna input and the second antenna output, the distance between the first antenna input and the first antenna output may be different from the distance between the second antenna input and the second antenna output. For example, for a second position relative to the second antenna output being different than the first position relative to the second antenna input, the distance between the first antenna input and the second antenna input may be different from the distance between the first antenna output and the second antenna output.

As an example, an arrangement may be a particular arrangement with respect to a grid on a coverage enhancing device, or an array, wherein each space on a grid can have a particular antenna, such as an antenna input and/or antenna output. Two arrays of a coverage enhancing device, may have different arrangements if the antennas, such as the antenna inputs and/or antenna outputs, on each of the two arrays are located in different grid spaces.

To provide for a further example, a first array may have four antennas, such as antenna elements, such as antenna inputs and/or antenna outputs. It may have an upper left antenna, an upper right antenna, a lower left antenna, and a lower right antenna. A second array may have four antennas, such as antenna inputs and/or antenna outputs. It may have an upper left antenna, an upper right antenna, a lower left antenna, and a lower right antenna.

Each antenna of the first array may be connected to an antenna in the second array. For example, when the upper left antenna of the first array is connected to the upper left antenna of the second array, the upper right antenna of the first array is connected to the upper right antenna of the second array, the lower left antenna of the first array is connected to the lower left antenna of the second array, and the lower right antenna of the first array is connected to the lower right antenna of the second array, the relative arrangement between a first antenna input and first antenna output (e.g. the upper right antennas of the first and second arrays) may be considered to be the same as the relative arrangement between a second antenna input and a second antenna output (e.g. the upper left antennas of the first and second arrays).

However, in a different scenario, the upper left antenna of the first array is connected to the upper right antenna of the second array, the upper right antenna of the first array is connected to the upper left antenna of the second array, the lower left antenna of the first array is connected to the lower left antenna of the second array, and the lower right antenna of the first array is connected to the lower right antenna of the second array. In this scenario, the relative arrangement between a first antenna input (upper right antenna of the first array) and a first antenna output (upper left antenna of the second array) may be considered to be different from a relative arrangement between a second antenna input (upper left antenna of the first array) and a second antenna output (upper right antenna of the second array).

As a further example, a relative arrangement of a first antenna input and a first antenna output being different from a relative arrangement of a second antenna input and a second antenna output can include, for a single array coverage enhancing device, that a position of the first antenna input on the coverage enhancing device, such as a location on the grid of antennas, compared to a position of the first antenna output on the coverage enhancing device, such as a location on the grid of antennas, are different than a position of the second antenna input on the coverage enhancing device, such as a location on the grid of antennas, compared to a position of the second antenna output on the coverage enhancing device, such as a location on the grid of antennas. If the position of the first antenna input and the position of the first antenna output were the same antenna and a position of the second antenna input and a position of the second antenna output were on an antenna different from the antenna of the first antenna input and the first antenna output, they would have the same relative arrangement. However, if the same arrangement is maintained but the second antenna output was on a different antenna from the second antenna input, the relative arrangement would be different.

With respect to a two array configuration, each antenna input on a first array can be connected to an antenna output on the second array. For example, if, while facing the same way and having the same size, the second array was placed directly on the first array, the relative arrangement of the first antenna input and the first antenna output would be different from a relative arrangement of the second antenna input and the second antenna output if one or more of the antenna inputs did not line up with the respective connected antenna outputs. If all antenna inputs aligned with the respective antenna outputs, the relative arrangements would be considered the same.

As used herein, random can mean without structured order. For example, random and/or randomized connections can mean that there is little or no structured order to the relative locations, such as between relative locations of a first antenna and a first antenna output. For example, the connections between antenna inputs and antenna outputs can be random, for example with no or minimal structured order. Random, as discussed herein, can be pseudo random. Random, as discussed herein, can be connections that behave as a random connection. Random could mean that the coverage enhancing device could have a relative arrangement.

Fig. 1 illustrates a schematic of a coverage enhancing device 10 having two arrays, a first array 12 and a second array 14. The coverage enhancing device 10 as illustrated in Fig. 1 may comprise a planar array of reflecting antenna elements. Each of the first array 12 and the second array 14 includes a plurality of antennas 16, such as antenna elements. As shown, the two arrays are connected via connectors 20 (e.g., electrical wires) in the same arrangement.

For example, antenna 18A of the first array 12 is connected to antenna 18B of the second array 14 via a connector 20. Antenna 18A is located in the same relative position on the first array 12 as antenna 18B is on the second array 14. To clarify, antenna 18A is located on the bottom row, second column of the first array 12 and antenna 18B is located on the bottom row, second column of the second array 14. A connected pair of antennas, such as antenna 18A and antenna 18B can be considered a pair of antennas. All pairs of antennas on the coverage enhancing device 10 would be connected via a connector 20, but only two such connections are shown for convenience. Every antenna of the plurality of antennas 16 on the first array 12, for example antenna inputs, would be connected to a respective antenna of the plurality of antennas 16 on the second array 14, for example antenna outputs, at the same relative arrangement.

The coverage enhancing device 10 can optionally include phase changers 22 and/or gain changers 24. This legacy configuration of a coverage enhancing device 10 has significant drawbacks, in that unwanted signals are transmitted with the same beamforming gains as for the wanted signals. Fig. 2 illustrates such problems for a one-dimensional (e.g., a single row of antenna elements) coverage enhancing device, but the same problems exist for other structures of coverage enhancing devices, such as the two-dimensional coverage enhancing device 10 of Fig. 1.

Fig. 2 illustrates beamforming gain for a one-dimensional coverage enhancing device. In Fig. 2, the beamforming gain is plotted for an incoming signal with direction angle of arrival (AoA) to an outgoing direction angle of departure (AoD). The coverage enhancing device has been configured to reflect, such as transmit, an incoming angle, or angle pair, with respect to the array’s broadside direction, of 30° to an outgoing direction of -20°. This is indicated by an “x” 40 in Fig. 2. As is seen, the coverage enhancing device can properly reflect the signal it has been configured to reflect, but it also reflects, equally well, a wide range of other angle-pairs. This may cause interference into the system, since a signal arriving at the coverage enhancing device, from any direction, will be reflected equally well to some other direction. Further, the observations of Fig. 2 are not limited to linear arrays, but hold true also for planar (2D) arrays, such as the coverage enhancing device 10 shown in Fig. 1. Accordingly, it would be advantageous to remove and/or reduce the beamforming gain for the wide range of other angle-pairs that the coverage enhancing device 10 is not configured to reflect.

Fig. 3 is a schematic of an example coverage enhancing device 100 according to the disclosure. The coverage enhancing device 100 may have one or more of a processor and a memory. In one or more example coverage enhancing devices, the coverage enhancing device 100 can include a first antenna input 102. In one or more example coverage enhancing devices, the first antenna input 102 can be configured to receive a first signal 101. In one or more example coverage enhancing devices, the coverage enhancing device 100 can include a second antenna input 104. In one or more example coverage enhancing devices, the second antenna input 104 can be configured to receive a second signal 103. In one or more example coverage enhancing devices, the coverage enhancing device 100 can include a first antenna output 106. In one or more example coverage enhancing devices, the first antenna output 106 can be configured to output the first signal 101. In one or more example coverage enhancing devices, the coverage enhancing device 100 can include a second antenna output 108. In one or more example coverage enhancing devices, the second antenna output 108 can be configured to output the second signal 103. In one or more example coverage enhancing devices, a relative arrangement of the first antenna input 102 and the first antenna output 106 can be different from a relative arrangement of the second antenna input 104 and the second antenna output 108.

In one or more example coverage enhancing devices, the first antenna input 102 may be a first input-antenna. In one or more example coverage enhancing devices, the first antenna input 102 may be a first antenna-input. In one or more example coverage enhancing devices, the second antenna input 104 may be a second input-antenna. In one or more example coverage enhancing devices, the second antenna input 104 may be a second antenna-input. In one or more example coverage enhancing devices, the first antenna output 106 may be a first output-antenna. In one or more example coverage enhancing devices, the first antenna output 106 may be a first antenna-output. In one or more example coverage enhancing devices, the second antenna output 108 may be a second output-antenna. In one or more example coverage enhancing devices, the second antenna output 108 may be a second antenna-output.

Advantageously, the coverage enhancing device 100 can be configured to reduce parasitic reflection which occurs in the coverage enhancing device 10 discussed with respect to Fig. 1 . For example, only the signals that the coverage enhancing device 100 is configured to reflect, such as redirect and/or transmit, are reflected, such as redirected and/or transmitted, and all others may be scattered.

The first signal 101 and the second signal 103 may be different received signals. The first signal 101 and the second signal 103 may be the same signal received at different places. Therefore, the first signal 101 and the second signal 103 as received may only differ by a phase shift, or may not differ at all.

The first antenna input 102 may be an antenna, such as an antenna element. The second antenna input 104 may be an antenna, such as an antenna element. The first antenna output 106 may be an antenna, such as an antenna element. The second antenna output 108 may be an antenna, such as an antenna element. In one or more example coverage enhancing devices, the coverage enhancing device 100 may be configured to phase shift the first signal 101 and/or the second signal 103. For example, the coverage enhancing device 100 may be configured to do one or more of: shift a phase, apply a phase shift, and change a phase.

In one or more example coverage enhancing devices, the coverage enhancing device 100 can be configured to increase a power density of the first signal 101 and/or the second signal 103. For example, the coverage enhancing device 100 may be configured to amplify the power of the first signal 101 and/or the second signal 103. For example, the coverage enhancing device 100 may be configured to increase the power density in a certain direction and/or location based on an incoming direction and/or location. This can ensure that all signals arrive coherently in the outgoing direction and/or location.

In one or more example coverage enhancing devices, the relative arrangement of the first antenna input 102 and the first antenna output 106 being different from the relative arrangement of the second antenna input 104 and the second antenna output 108 can include the first antenna input 102 having a first position relative to the second antenna input 104. In one or more example coverage enhancing devices, the relative arrangement of the first antenna input 102 and the first antenna output 106 being different from the relative arrangement of the second antenna input 104 and the second antenna output 108 can include the first antenna output 106 having a second position relative to the second antenna output 108. The second position relative to the second antenna output 108 can be different than the first position relative to the second antenna input 104.

For example, in the coverage enhancing device 100 shown in Fig. 3, the coverage enhancing device 100 can have randomized wiring, such as by having randomized connections between antenna inputs and antenna outputs. In this regard, “randomized” can mean that there is little or no structured order to the relative locations of a first antenna input 102 and a corresponding first antenna output 106 within their respective antenna arrays. Unlike the coverage enhancing device 10 discussed with respect to Fig. 1 , the relative arrangement of the antenna inputs and antenna outputs of the coverage enhancing device 100 are different. For example, the first antenna input 102 may not be connected to a first antenna output 106 at the same position on a first array 120 for the first antenna input 102 as the first antenna output 106 on the second array 122. The coverage enhancing device 100 may include a first array 120 and a second array 122. The coverage enhancing device 100 may include further arrays.

In one or more example coverage enhancing devices, the relative arrangement of the first antenna input 102 and the first antenna output 106 being different from the relative arrangement of the second antenna input 104 and the second antenna output 108 can include the relative arrangement being different in one or more of: an x-direction, a y- direction, and a z-direction. The x-direction, y-direction, and/or z-direction may be with respect to an axis formed with respect to an individual coverage enhancing device. Thus, if two arrays of a coverage enhancing device are spatially spaced apart, the first antenna input and first antenna output on a first array could have the same relative arrangement of a second antenna input and second antenna output on a second array, despite the two arrays being spatially different.

In one or more example coverage enhancing devices, the first antenna input 102 is a first antenna on a first array 120. In one or more example coverage enhancing devices, the first antenna output 106 is a second antenna on an array 122.

As shown, the coverage enhancing device 100 may include a first array 120, and a second array 122. Each of the first array 120 and the array 122 of the coverage enhancing device 100 may include a number of antennas, such as antenna elements. The antennas may be, for example, the first antenna input 102, the second antenna input 104, the first antenna output 106, and the second antenna output 108.

First array 120 can receive the signal(s) using M antennas. The received signal at each antenna can be phase changed, possibly amplified, and then transmitted from another antenna of the second array 122.

In one or more example coverage enhancing devices, the second antenna input 104 is a third antenna on the first array 120. In one or more example coverage enhancing devices, the second antenna output 108 is a fourth antenna on the second array 122. In this manner, the relative arrangement of the first antenna input 102 to the first antenna output 106 can be different from the relative arrangement of the second antenna input 104 to the second antenna output 108. The first antenna, such as being the first antenna input 102, can be connected to the second antenna, such as being the first antenna output 106. For example, they can be electrically connected. The third antenna, such as being the second antenna input 104, can be connected to the fourth antenna, such as being the second antenna output 108. For example, they can be electrically connected.

For example, the first antenna and the second antenna can be connected via a first connector 124, thus providing a connection between the first antenna input 102 and the first antenna output 106. The third antenna and the fourth antenna can be connected via a second connector 126, thus providing a connection between the second antenna input 104 and the second antenna output 108.

The first connector 124 and/or the second connector 126 can be physical connectors. The first connector 124 and/or the second connector 126 can be electrical connectors. The first connector 124 and/or the second connector 126 can be wireless connectors.

All pairs of antennas, such as an antenna input connected to an antenna output, would be connected in the coverage enhancing device 100, but only a few of such connections are shown for convenience and clarity of the figure. The coverage enhancing device 100 may include phase changes and gains, or other components, which are not shown for clarity. For example, the connectors, such as first connector 124 and/or second connector 126, can be configured to apply phase changes and/or gains.

As shown in Fig. 3, a relative arrangement of the first antenna input 102 and the first antenna output 106 is different from a relative arrangement of the second antenna input 104 and the second antenna output 108. For example, the first antenna input 102 can be located in the third column, first row while the first antenna output 106 can be located on the fourth column, bottom row. Further, the second antenna input 104 can be located on the first column, second row while the second antenna output 108 can be located on the fourth column, third row. Thus, the relative arrangement can be different. Other different relative arrangements can be used, and this is merely one example. A change in one input being connected to an output at a different relative position, or arrangement, can be a different relative arrangement. The connections between antenna inputs and antenna outputs can be random, for example with no or minimal structured order. The connections between antenna inputs and antenna outputs can be not-fully aligned. The connections between antenna inputs and antenna outputs can be only partially aligned. The connections between antenna inputs and antenna outputs can be mirrored. The connections between antenna inputs and antenna outputs can be switched in relative position. At least one antenna input can be positioned differently on the first array as compared to a relative position of its connected antenna output.

The coverage enhancing device 100 can include a “random realization of rewiring” as compared to the coverage enhancing device 10, which can reduce and/or eliminate parasitic reflections.

In one or more example coverage enhancing devices, the coverage enhancing device 100 is a reciprocal coverage enhancing device. In other words, the same antenna elements of the coverage enhancing device 100 can process both downlink (DL) and uplink (UL) transmissions without changing configurations of the coverage enhancing device 100.

In one or more example coverage enhancing devices, the coverage enhancing device 100 is a non-reciprocal coverage enhancing device. In other words, the antenna elements of the coverage enhancing device 100 is required to change configuration between downlink (DL) and uplink (UL) transmissions.

Fig. 4A-Fig. 4B show gain plots corresponding to a coverage enhancing device according to the present disclosure. Fig. 4A is a gain plot of a 16 antenna uniform linear array (ULA) configuration of a coverage enhancing device and Fig. 4B is a gain plot of a 32 antenna ULA configuration of a coverage enhancing device.

For both plots, the coverage enhancing device 100 has been configured and/or optimized to reflect an angle pair coinciding with the dot 402A or 402B, respectively. As can be seen, the coverage enhancing device reflects now in precisely those angles, and no others, although some traces of parasitic reflections are still left for Fig. 4A. Similar gain plots can also be created for uniformly rectangular array (URA) configurations for a coverage enhancing device, similar to the coverage enhancing device 100 of Fig. 3, and are plotted and discussed with respect to Fig. 5A- Fig. 6.

For URA configurations, it can be difficult to visualize the effect of the disclosure as there are four angles that need to be represented, and the combination would lead to a four dimensional image. In order to produce Figs. 5A-5B, the coverage enhancing device 100 having a 4x4 array has been optimized to reflect an incoming signal arriving from 40° azimuth and 30° elevation to an outgoing direction with 160° azimuth and 20° elevation. The coverage enhancing device angles have been kept constant and the beamforming gain has been computed for any other combination of four angles. The elevation angles have been parameterized as 0°:5°:60° and the azimuth angles have been parameterized as 0°:5°:355°. The data has been normalized so that the value T refers to a beamforming gain of M², which is the best value possible.

A vector has been constructed where each element holds the beamforming gain for some combination of the four angles. Both beamforming gains for angles that are at most ±5°, in all angles, away from the designed-for angles of the coverage enhancing device and all other angles have been plotted. Generally, dots appearing near the top of the y-axis of Figs. 5A-5B outside of around 0.2-0.4, which is the range 502A or 502B the particular coverage enhancing device is configured for, on the x-axis are parasitic reflections.

Fig. 5A illustrates results of a legacy coverage enhancing device, such as the coverage enhancing device 10 of Fig. 1 and Fig. 5B illustrates results of a coverage enhancing device according to this disclosure, such as coverage enhancing device 100 of Fig. 3.

As illustrated, Fig. 5A contains vastly more dots near the top, especially outside of the range 502A the coverage enhancing device 10 is configured for, and most of those correspond to a parasitic reflection. In Fig. 5B, most of these have vanished, and the majority of dots near the top are within the range 502B that the coverage enhancing device 100 is configured for. Increasing the array size from 4x4 to a larger array would eliminate even more parasitic reflections.

Moreover, Fig. 5B has a more natural higher floor, as the coverage enhancing device 100 can reflect all incoming energy somewhere in space, so the sum of all the points weighted with a cosine-kernel in the two figures must sum to the same value. Therefore, if parasitic reflections are eliminated the floor must rise. This can be interpreted to show that the example coverage enhancing device 100 of the disclosure can act as a scatterer for any incoming signals apart from the configured directions/angles.

Fig. 6 summarizes the plots of Fig. 5A-Fig. 5B as a cumulative distribution function (CDF). Line 602 illustrates a CDF with respect to the coverage enhancing device 100, and line 604 illustrates a CDF with respect to the coverage enhancing device 10. Fig. 6 shows the probability that a directional pair far from the designed for pair gives a large beamforming gain. Specifically, Fig. 6 illustrates that the number of directional pairs with large beamforming gain far away from the designed pair of directions will be minimized.

Fig. 7 is a schematic of an example coverage enhancing device 300 according to the disclosure. The coverage enhancing device 300 may have one or more of a processor and a memory.

In one or more example coverage enhancing devices, the coverage enhancing device 300 can include a first antenna input 302. The first antenna input 302 can be configured to receive a first signal 301. In one or more example coverage enhancing devices, the coverage enhancing device 300 can include a second antenna input 304. The second antenna input 304 can be configured to receive a second signal 303. In one or more example coverage enhancing devices, the coverage enhancing device 300 can include a first antenna output 306. The first antenna output 306 can be configured to output the first signal 301. In one or more example coverage enhancing devices, the coverage enhancing device 300 can include a second antenna output 308. The second antenna output 308 can be configured to output the second signal 303. In one or more example coverage enhancing devices, a relative arrangement of the first antenna input 302 and the first antenna output 306 can be different from a relative arrangement of the second antenna input 304 and the second antenna output 308.

In one or more example coverage enhancing devices, the first antenna input 302 may be a first input-antenna. In one or more example coverage enhancing devices, the second antenna input 304 may be a second input-antenna. In one or more example coverage enhancing devices, the first antenna output 306 may be a first output-antenna. In one or more example coverage enhancing devices, the second antenna output 308 may be a second output-antenna.

Advantageously, the coverage enhancing device 300 can be configured to reduce parasitic reflections. For example, only the signals that the coverage enhancing device 300 is configured to reflect, such as redirect and/or transmit, are reflected, such as redirected and/or transmitted, and all others may be scattered.

For example, the coverage enhancing device 300 can be configured such that the first signal 301 can be transmitted, such as reflected, from a different antenna than where it is received. The coverage enhancing device 300 can be configured such that the second signal 303 can be transmitted, such as reflected, from a different antenna than where it is received. The coverage enhancing device 300 can be configured such that every signal can be transmitted, such as reflected, from a different antenna than where it is received.

This can be different from some known coverage enhancing devices, where the first signal is received and transmitted, such as reflected, from the same antenna. However, this same receiving/transmitting antenna would produce the unwanted signal reflections, such as discussed in Fig. 2.

The first signal 301 and the second signal 303 may be different received signals. The first signal 301 and the second signal 303 may be the same signal received at different places. Therefore, the first signal 301 and the second signal 303 as received may only differ by a phase shift, or may not differ at all.

The first antenna input 302 may be an antenna, such as an antenna element. The second antenna input 304 may be an antenna, such as an antenna element. The first antenna output 306 may be an antenna, such as an antenna element. The second antenna output 308 may be an antenna, such as an antenna element.

In one or more example coverage enhancing devices, the coverage enhancing device 300 may be configured to phase shift the first signal 301 and/or the second signal 303. For example, the coverage enhancing device 300 may be configured to do one or more of: shift a phase, apply a phase shift, and change a phase. In one or more example coverage enhancing devices, the coverage enhancing device 300 can be configured to increase a power density of the first signal 301 and/or the second signal 303. For example, the coverage enhancing device 300 may be configured to amplify the power of the first signal 301 and/or the second signal 303. For example, the coverage enhancing device 300 may be configured to increase the power density in a certain direction and/or location based on an incoming direction and/or location. This can ensure that all signals arrive coherently in the outgoing direction and/or location.

In one or more example coverage enhancing devices, the relative arrangement of the first antenna input 302 and the first antenna output 306 being different from the relative arrangement of the second antenna input 304 and the second antenna output 308 can include the first antenna input 302 having a first position relative to the second antenna input. In one or more example coverage enhancing devices, the relative arrangement of the first antenna input 302 and the first antenna output 306 being different from the relative arrangement of the second antenna input 304 and the second antenna output 308 can include the first antenna output 306 having a second position relative to the second antenna output 308. The second position relative to the second antenna output 308 can be different than the first position relative to the second antenna input 304.

For example, in the coverage enhancing device 300 shown in Fig. 7, the coverage enhancing device 300 can have a randomized rewiring, such as by having randomized connections between antenna inputs and antenna outputs. For example, the relative arrangement of the antenna inputs and antenna outputs of the coverage enhancing device 300 are different, as the antenna input and respective connected antenna output are different antennas. For example, the first antenna input 302 may not be the same antenna as the first antenna output 306. The relative arrangement of the first antenna input 302 and the first antenna output 306 would be different from the relative arrangement of the second antenna input 306 and the second antenna output 308.

In one or more example coverage enhancing devices, the relative arrangement of the first antenna input 302 and the first antenna output 306 being different from the relative arrangement of the second antenna input 304 and the second antenna output 308 can include the relative arrangement being different in one or more of: an x-direction, a y- direction, and a z-direction. The x-direction, y-direction, and z-direction can be with respect to a relative axis of the coverage enhancing device 300.

In one or more example coverage enhancing devices, the first antenna input 302 can be a first antenna on a first array 310. In one or more example coverage enhancing devices, the first antenna output 306 is a second antenna on the first array 310.

In one or more example coverage enhancing devices, the coverage enhancing device 300 can have a single array of antennas. This can differ from the coverage enhancing device 100 discussed above with respect to Fig. 3, which can include a plurality of arrays.

In one or more example coverage enhancing devices, the second antenna input 304 can be the second antenna. For example, the second antenna can act as both the first antenna output 306 and the second antenna input 304. Each antenna on the coverage enhancing device 300 may act as both an antenna input and an antenna output. At least one antenna on the coverage enhancing device 300 can have an antenna which has an antenna input unconnected to an antenna output on the antenna. At least one antenna being a first antenna input 302 is connected to a different antenna being the first antenna output 306.

In one or more example coverage enhancing devices, the second antenna input 304 can be a third antenna. This configuration is shown in Fig. 7.

The coverage enhancing device 300 can include further components which may help direct the first signal 301 and/or the second signal 303 between different antennas. In one or more example coverage enhancing devices, the coverage enhancing device 300 can include a first circulator 312. The first signal 301 can be configured to pass through the first circulator 312. For example, each antenna element can include a circulator that can define the feeds to an antenna input and an antenna output.

In one or more example coverage enhancing devices, the coverage enhancing device 300 can include an additional input circulator 314. The second signal 303 can be configured to pass through the additional input circulator 314.

The coverage enhancing device 300 can include further circulators. For example, the coverage enhancing device 300 can have a circulator for every antenna input. In one or more example coverage enhancing devices, the coverage enhancing device 300 can include a second circulator 316. The first signal 301 can be configured to, after passing through the first circulator 312, pass through the second circulator 316.

In one or more example coverage enhancing devices, the coverage enhancing device 300 can include an additional output circulator 318. The second signal 303 can be configured to pass through the additional output circulator 318.

The coverage enhancing device 300 can include further circulators. For example, the coverage enhancing device 300 can have a circulator for every antenna output. The coverage enhancing device 300 can have a circulator for every antenna output and for every antenna input.

The coverage enhancing device 300 can include further components as well. For example, the coverage enhancing device 300 can include a ground plate 320. For example, when a particular signal path sees a mismatch, which may be an open-ended or infinite impedance mismatch, or a short circuit or zero impedance mismatch, there can be a reflection generated. The reflected signal can travel the opposite direction compared to the original signal. The signal can reflect off ground plate 320.

The first signal 301 and/or the second signal 303 can be configured to be reflected from an impedance mismatch, such as at ground plate 320.

In one or more example coverage enhancing devices, the coverage enhancing device can include a phase shifter 322 between circulators, such as between the first circulator 312 and the second circulator 316. There may be a phase shifter 322 between every set of circulators. The coverage enhancing device 300 can further include an amplifier, for example an amplifier for each antenna input. There may be an amplifier between every set of circulators.

In one or more example coverage enhancing devices, each antenna element can have one or more circulators connected to its feed. The circulator(s) can direct the received signal to a phase-shifter (or delay-line) and optionally an amplifier. This signal can then be fed to a different random antenna where it is directed by a circulator to the antenna. The inputs and outputs, such as the first antenna input 302, the second antenna input 304, the first antenna output 306, and the second antenna output 308, can then be combined in a random fashion or selected to suppress undesired reflection properties.

In one or more example coverage enhancing devices, as shown in Fig. 7, the circulators 312, 314, 316, 318 are optional. For example, the coverage enhancing device 300 can have no circulators. In other words, the coverage enhancing device 300 can be circulator- free. In one or more example coverage enhancing devices, the coverage enhancing device 300 does not include a circulator. Stated differently, such example coverage enhancing devices 300 are circulator-free. In one or more example coverage enhancing devices, connections in the coverage enhancing device 300 do not include circulators.

FIG. 10 illustrates a schematic of a circulator-free coverage enhancing device 500 (not all antenna element connections are shown for convenience). The circulator-free coverage enhancing device 500 can include any and/or all of the features discussed above with respect to coverage enhancing device 200 and/or coverage enhancing device 300. As shown, the circulator-free coverage enhancing device 500 can include one or more phase changers 502.

Removing circulators from the coverage enhancing device may be advantageous as circulators can be bulky and expensive. Accordingly, removing circulators from a coverage enhancing device can advantageously allow for one or more of: cheaper manufacturing, improved efficiencies, improved isolation, reduction in complexity, reduction in size, and reduction of loss (every component adds loss to a system). A circulator-free coverage enhancing device 500 may use a single antenna array. A circulator-free coverage enhancing device 500 can be a reciprocal coverage enhancing device. In some examples, the circulator-free coverage enhancing device 500 is reciprocal by design and cannot be a non-reciprocal coverage enhancing device. As the circulator-free coverage enhancing device 500 can be reciprocal, it may not need to be aware of the uplink (UL) and/or downlink (DL) configurations. In one or more example coverage enhancing devices, the circulator-free coverage enhancing device 500 does not include any amplifiers. In one or more example coverage enhancing devices, the circulator-free coverage enhancing device 500 is a single array of antennas. The first antenna input 302 and the first antenna output 306 can be connected via a first connector 324. The second antenna input 304 and the second antenna output 308 can be connected via a second connector 326.

The first connector 324 and/or the second connector 326 can be physical connectors. The first connector 324 and/or the second connector 326 can be electrical connectors. The first connector 324 and/or the second connector 326 can be wireless connectors.

All pairs of antennas, such as an antenna input connected to an antenna output, would be connected in the coverage enhancing device 300, but only a few of such connections are shown for convenience. The coverage enhancing device 300 may include phase shifters and amplifiers, or other components, some of which are not shown for clarity. For example, the connectors, such as first connector 324 and/or second connector 326, can be configured to apply phase changes and/or gains.

Antennas in the coverage enhancing device 300 can be connected randomly for respective antenna inputs and antenna outputs.

Fig. 8 illustrates a schematic coverage enhancing device 50. The coverage enhancing device 50 can include a plurality of antennas 52. As shown, the plurality of antennas 52 are spaced apart regularly. However, this may create unwanted reflections as discussed above.

Fig. 9 illustrates an example schematic coverage enhancing device 200 according to the disclosure. The coverage enhancing device 200 may have one or more of a processor and a memory.

In one or more example coverage enhancing devices, the coverage enhancing device 200 can include a plurality of antennas 202 arranged on the coverage enhancing device 200.

In one or more example coverage enhancing devices, at least some antennas of the plurality of antennas 202 are spaced apart irregularly on the coverage enhancing device 200. In one or more example coverage enhancing devices, the plurality of antennas 202 is configured to reduce parasitic reflections of the coverage enhancing device 200.

Spacing apart can be, for example, inter-element and/or inter-antenna spacing. Spaced irregularly apart can include being spaced randomly apart. Spaced irregularly apart can include being spaced semi-randomly apart. Spaced irregularly apart can include antennas having different spacings between adjacent antennas. Spaced irregularly apart can be non-uniform spacing.

For example, the plurality of antennas 202 may be spaced differently from a typical half a wavelength, either electrically or physically, apart. Typical antennas are spaced half a wavelength apart. The wavelength can be a wavelength of the signal that the coverage enhancing device 200 is configured to receive.

The coverage enhancing device 200 may be a reflective surface. The coverage enhancing device 200 may include one or more reflective surfaces.

In one or more example coverage enhancing devices, each of the plurality of antennas 202 is spaced irregularly. In one or more example coverage enhancing devices, most of the plurality of antennas 202 is spaced irregularly. In one or more example coverage enhancing devices, some of the plurality of antennas 202 is spaced regularly.

In one or more example coverage enhancing devices, the at least some antennas of the plurality of antennas 202 are spaced apart along a z-axis with respect to the coverage enhancing device 200.

The coverage enhancing device 200 can be a single array. The coverage enhancing device 200 can be multiple arrays.

Advantageously, at least the quarter circle in the bottom left corner of Fig. 2 can be reduced and/or removed. Thus, the coverage enhancing device 300 can be capable of eliminating or reducing at least some of the parasitic reflections.

In one or more example coverage enhancing devices, the coverage enhancing device 100 and/or the coverage enhancing device 300 as discussed above could further include the irregularly spacing discussed with respect to the coverage enhancing device 200. For example, the coverage enhancing device 100 can include some or all of the elements of coverage enhancing device 200 and vice versa. The coverage enhancing device 300 can include some or all of the elements of coverage enhancing device 200 and vice versa. Fig. 11 illustrates an example schematic coverage enhancing device 600 according to the disclosure. The coverage enhancing device 600 may have one or more of a processor and a memory. The coverage enhancing device 600 can include any and/or all of the features discussed above with respect to coverage enhancing device 200, coverage enhancing device 300, and/or coverage enhancing device 500.

In one or more example coverage enhancing devices, the coverage enhancing device 600 can utilize “beam splitting”. As used herein, beam splitting can include receiving a signal (e.g., first signal 101 , second signal 103) and re-transmitting the signal into two different directions. While Fig. 11 illustrates beam splitting, the benefit associated herein is that this beam splitting allows for the coverage enhancing device 600 to obtain reciprocity. In particular, this is done because reciprocity means that signal should be sent over two directed channels (UE->gNB, and gNB->UE). Mathematically, this is no different from sending signals to two different directions. So, to create reciprocity, beam-splitting can be used, but where the two directions (such as 101 A and 101 B in Fig. 11 ) now refer to UE- >gNB and gNB->UE.

In one or more example coverage enhancing devices, the coverage enhancing device 600 can be configured to split the first signal 101 into at least two first signals 101 A, 101 B and/or split the second signal 103 into at least two second signals 103A, 103B. In one or more examples or embodiments, the at least two first signals 101A, 101 B have different directionality and/or the at least two second signals 103A, 103B have different directionality. For example, the at least two first signals 101 A, 101 B and/or the at least two second signals 103A, 103B can have different phase shifts. The at least two first signals 101A, 101 B and/or the at least two second signals 103A, 103B can include the same information as the respective first signal 101 and second signal 103. The coverage enhancing device 600 can be configured to receive a configuration signal 406, wherein the configuration signal 406 is indicative of the directionality of the at least two first signals 101A, 101 B and/or the at least two second signals 103A, 103B. In one or more examples or embodiments, the coverage enhancing device 600 can include bidirectional amplifiers between antenna pairs.

Fig. 11 illustrates a schematic of a base station 400 (e.g., gNB) and a coverage enhancing device 600. The base station 400 can send a signal (e.g., first signal 101 , second signal 103) towards the coverage enhancing device 600 which should be “split” at the coverage enhancing device 600 so that a fraction of the impinging signal power is reflected in a first directionality (first signal 101 A, second signal 103A) and another fraction in a second directionality (first signal 101 B, second signal 103B). Note that the signals reflected (101A, 101 B) to the can be identical to the received signal (101), save for a scaling factor that can be controlled by the coverage enhancing device 600. Further, the base station 400 can be configured to send a configuration signal 406 to the coverage enhancing device 600.

Fig. 12 illustrates a beamforming gain plot of the example coverage enhancing device 400 according to the disclosure. Similar to Figs. 4A-4B, all or a majority of parasitic reflections have vanished. While Figs. 4A-4B illustrate a single angle of arrival is reflected, Fig. 12 illustrates both a downlink and an uplink reflection. Figs. 4A-4B imply that the coverage enhancing device reflects signal from, say, the base station to the UE, but not in the reverse direction. So the coverage enhancing device may need to be reconfigured whenever there is a switch between UL and DL even though the spatial directions remain the same. Advantageously, Fig. 12 does illustrate that a reconfiguration is not needed. In Fig. 12, it is assumed that the base station and the UE are located at angles a and with respect to the coverage enhancing device, respectively. If the coverage enhancing device has reflection characteristics according to Fig. 12, no reconfiguration is needed between UL and DL.

Examples

Example 1

The following disclosure illustrates some of the benefits of the coverage enhancing devices according to the disclosure, such as coverage enhancing device 100, coverage enhancing device 200, and/or coverage enhancing device 300. The examples are merely exemplary, and the disclosure should not be so limited.

Let the M antennas be located at

but at z=0. Assume an incoming planar wave from angles (AoA) <p, 0 (first is azimuth, second is elevation) and consider the coverage enhancing device response, up to a constant common for all M antennas, in an AoD <p, 0

Where:

Note that the notation suppresses the dependency on Assume an

inter-antenna spacing of 2/2 in both x and y directions, to obtain:

where c_{k n} traverses c_m row by row.

Assume now, for the same set c_kJl, another signal arriving from It can be

asked whether there exists a pair such that:

Where:

This may imply that the new combination of AOAs and AoDs is reflected equally well as the other pair. For any such pair may exist.

In fact, it may be sufficient if the following is satisfied:

where

there is can be a unique solution (to (2)) given by:

where mod

The implication can be that the beamforming gain between

p ^ ₀ and is identical to that between no matter the

values of and the coverage enhancing device coefficients c_{k n}.

Regarding example coverage enhancing device 200 with respect to Fig. 9, the interelement spacing is not 2/2, the more restricted set of equations can be satisfied: (3)That is,

can hold in (2). This can imply that whenever any of

the modulus operations is “active”, i.e., or

then there may be no solution in the sense that there may be no pair that solves

the two equations in (1 ). Thus, at least some of the parasitic reflections can be eliminated.

Regarding the example coverage enhancing devices 100/300 of the disclosure shown in Fig. 3 and Fig 7, equation (1 ) can change into:

where is the same numbers as

but taken in another order. This can imply that the x_m terms cannot be factored out as before, or, in other words, A and A may not enter the expression solely through A + A (and similar for B/B).

This can imply that the set of two equations solved without rewiring, e.g., with the same arrangement, now expands into the 2M equations (one pair for each value of m):

for all values of But as the number of variables is far less than 2M, there may

be little hope in satisfying all equations simultaneously. Therefore, the parasitic reflections can reduce and/or vanish.

The following can apply to situations where two arrays are used, and where the two communication nodes, such as a base station or next generation Node B (gNB) and a user equipment (UE), are located such that the UE can only see one array and the gNB can only the other array.

It is well understood that the transfer function of a phase-shifting coverage enhancing device can be represented by a diagonal matrix with unit-magnitude elements

on the diagonal, i.e.:

where part of the configured state can be seen as related to incoming waves (i.e., and part to outgoing waves

such that

and zero otherwise. Rewiring the unit cells and/or antennas, such as forming the different relative arrangements discussed herein, could correspond to inserting a permutation matrix P_n, i.e.:

such that > and zero otherwise. Local rewiring of the unit

cells and/or antennas such as forming the different relative arrangements discussed herein, could correspond to inserting a block-diagonal matrix:

where are permutation matrices and it is assumed that N is divisible

by the number, B, of permutation matrices.

In general, the above networks are non-reciprocal. That is, the behavior of the network changes when inputs and outputs can be reversed. This is not a problem for coverage enhancing device implementations consisting of two arrays facing opposite directions, and unit cells, such as antennas, wired according to P_n. If reciprocity of the coverage enhancing device is desired, e.g., to uphold the reciprocity of the radio channel in the base station to user equipment and user equipment to base station directions, permutation matrices can be used that satisfy:

Example 2

Figs. 13A-13C illustrate a particular coverage enhancing device (Fig. 13A) and a circulator-free coverage enhancing device (Fig. 13C) which is reciprocal. Further, Fig. 13B can be understood as showing an attempt at a coverage enhancing device which is a generalization of Fig. 13A by adding more phase shifters. However, as discussed below, the phase shifters do not appear to improve the cover enhancing device, thus illustrating that the coverage enhancing device of Fig. 13A cannot be easily fixed by adding phase shifters at places where there are no phase shifters.

The coverage enhancing devices of Figs. 13A-13C can be the coverage enhancing devices as discussed herein. Figs. 13A and 13B illustrate coverage enhancing devices 1300A, 1300B with phase changers 1302, amplifiers 1304, and circulators 1306. As noted, Fig. 13B includes additional phase changers 1302 as compared to Fig. 13A. Fig. 13C illustrates a circulator-free coverage enhancing device 1300C including phase changers 1302.

For an impinging wave from spherical direction

the mathematical model for the reflected signal along an outgoing direction

is

where s(-) are column steering vectors, £>(y) is a diagonal matrix with the values e^iy along its main diagonal, and P is a permutation matrix describing the permutation o

On the other hand, for the coverage enhancing device 1300B of Fig. 13B, the signals are affected by the phase shifts a both at arrival and at departure due to the extra phase changers 1302. Thus, the model becomes

From elementary matrix algebra, it follows that , where should be

interpreted as the inverse permutation of the phases a. Further, as diagonal matrices and phase values are in the product

Thus,

From this expression it follows that choosing

yields:

The adaptive reciprocity/non-reciprocity mode of Figs. 13A-13B comes about by a choice of the phase values y. Or more precisely, there exists a setting y such that

However, a 4dB loss may be incurred to

compared to the y that maximizes

Moving to the circulator-free coverage enhancing device 1300C of Fig. 13C, the number of elements in the sequence δ is half of that in y. Further, the permutation matrix built into the implementation is symmetric

. It can be advantageous to work with a phase vector 6 having the same number of elements as the number of antenna elements, which can be accomplished if an extended phase vector

is defined which satisfies:

In words, if, say, antennas 15 and 37 are connected, then from symmetry of the permutation is = 1. A vector 6 satisfying the definition must have its

15th and 37th elements to be equal, i.e

However, this value is free to select, thus, there are as many degrees of freedom (DoFs) in 6 as in 6.

With that, the mathematical model of the circulator-free coverage enhancing device 1300C can be seen as:

To see that this expression is always reciprocal, note that for a symmetric

from which in the reverse direction the following is obtained:

where the second equality follows since there are scalar valued quantities, and the third from the observation just above. It is established that reciprocity always holds and cannot be avoided by tuning

Next is the optimization of the vector

As the coverage enhancing device 1300B, 1300C is reciprocal, it suffices to optimize it for the forward direction:

Define the row vector s

^₂ ^₁ be a pair such that which by necessity forces

but

by definition, so:

Where But from this expression, to optimize 8_t, namely, it should be

selected such that:

This expression can be recognized as the beam splitting formula.

Let us now contrast this with the implementation in Figs. 13A-13B operated in reciprocal mode. The permutation in Figs. 13A-13B needs not to be symmetric, but to obtain a fair comparison a symmetric permutation is assumed. Note that even with a symmetric permutation, it might not a-priori be clear how the two implementations compare, as the one in Figs. 13A-13B has twice the number of phase shifters 1302.

The model for the left implementation is:

As this implementation is not reciprocal by default, y is tuned so that it is. Recall the definition To make it reciprocal, beam splitting is applied, so that:

Consider now k and k' such that for some value . It is easily verified

that

(this follows from the symmetry of P). Thus, to optimize

Thus, for a symmetric permutation, the phases in the implementation of Figs. 13A-13B always appear in pairs, and the corresponding phases are identical to those of the circulator-free coverage enhancing device 1300C of Fig. 13C.

Thus, with symmetric permutations, the circulator-free coverage enhancing 1300C device of Fig. 13C and the coverage enhancing devices 1300A, 1300B of Figs. 13A-13B are identical. The benefit of the circulator-free coverage enhancing device 1300C of Fig. 13C is that it is free from circulators. The benefit of the coverage enhancing devices 1300A, 1300B of Figs. 13A-13B may be that gains are possible by using non-symmetric permutations and also that the reciprocity can be turned off to gain 4 dB.

Example 3

The following example uses an embodiment of a beam-forming coverage enhancing device 600 according to the disclosure. In particular, the example shows how beamsplitting can be used to create reciprocity. While beam-splitting is usually thought of as two “spatial directions”, it can be shown to be two “directed directions”.

Part 1

This part of Example 3 illustrates what to do if for sending a signal in two directions (e.g., beam-splitting). With a far-field model, incoming signal at the coverage enhancing device across its M antennas can be described by the M x 1 steering vector s(k_gNB). Similarly, the channels from the coverage enhancing device to the UEs are described by the steering vectors The variables “k” denote directional cosine

vectors comprising the spatial directions. With that, within the directions of the gNB and UE beams, the received signals (in the absence of noise) at the UEs read:

where x is the information symbol sent by the gNB, z is an M x 1 vector of complex exponentials representing the phase shifts applied at the coverage enhancing device, s_n is an “effective” 1 x M steering vector between the gNB and UE n, and all scalings have been removed (e.g., path loss, array gains, etc.). The notation “diag” is a diagonal matrix with its argument along the main diagonal.

For a beam split to happen, it may be advantageous that both A₁ and ₂ are large. With perfect fairness, the following optimization problem can be solved:

P such that min

As M grows large, the solution to this problem is P = AM²/n² achieved by:

where s_nm is element m of s_n. If a non-fair situation is desired, i.e., il #= M21 it can be optimal to construct z_m as: and then determining (Technically, the solution to the problem

such that is of this form for some Further, the magnitude

of 2i can be set to unity.) Based on the implementations described herein, the signal pattern illustrated in Fig. 12 can be formed by making use of beam splitting in a coverage enhancing device.

Part 2

Part 2 of Example 3 illustrates the case of a single UE, and observes that reflections in two “directed directions” are needed. For the implementations disclosed herein, a mathematical model for the downlink is (within the gNB and UE beams)

where P is a permutation matrix. Similarly, in the uplink:

The two vectors s_DL and s_UL are both 1 x M vectors. To make the coverage enhancing device reciprocal in UL and DL, it is advantageous that both quantities |s_ULz|² and |s_DLz|² are large. This is, mathematically, the same setup as for beam splitting. However, in the beam splitting case, the two effective steering vectors

and s₂ correspond to different UEs, while for reciprocity, the two vectors s_DL and s_UL correspond to the DL and UL between the gNB and a single UE. The beam splitting method can be applied to the vectors s_DL and s_UL. Thus,

A common situation is that the UE is power limited. For that case, one can use

With 2 > 1 in order to achieve better reflection in the UL than in the DL.

Due to the solution of the optimization problem being about 4dB (compared

to a non-reciprocal but rewired RIS) may be lost. Accordingly, the price to pay for reciprocity can be 4dB, but with a coverage enhancing device with built in amplification, this loss may be compensated for. Therefore, a fully reciprocal and parasitic-free coverage enhancing device can be obtained.

Examples of methods and products (coverage enhancing devices) according to the disclosure are set out in the following items:

Item 1 : A coverage enhancing device comprising: a first antenna input configured to receive a first signal; a second antenna input configured to receive a second signal; a first antenna output configured to output the first signal; and a second antenna output configured to output the second signal; wherein a relative arrangement of the first antenna input and the first antenna output is different from a relative arrangement of the second antenna input and the second antenna output.

Item 2: Coverage enhancing device of Item 1 , wherein the coverage enhancing device is configured to phase shift the first signal and/or the second signal.

Item 3: Coverage enhancing device of Item 1 or Item 2, wherein the coverage enhancing device is configured to increase a power density of the first signal and/or the second signal.

Item 4: Coverage enhancing device of any one of the preceding Items, wherein the relative arrangement of the first antenna input and the first antenna output being different from the relative arrangement of the second antenna input and the second antenna output comprises: the first antenna input having a first position relative to the second antenna input; and the first antenna output having a second position relative to the second antenna output; wherein the second position relative to the second antenna output is different than the first position relative to the second antenna input.

Item 5: Coverage enhancing device of any one of the preceding Items, wherein the relative arrangement of the first antenna input and the first antenna output being different from the relative arrangement of the second antenna input and the second antenna output comprises the relative arrangement being different in one or more of: an x-direction, a y- direction, and a z-direction.

Item 6: Coverage enhancing device of any one of the preceding Items, wherein: the first antenna input is a first antenna on a first array; and the first antenna output is a second antenna on the first array.

Item 7: Coverage enhancing device of Item 6, wherein the second antenna input is the second antenna.

Item 8: Coverage enhancing device of Item 6, wherein the second antenna input is a third antenna.

Item 9: Coverage enhancing device of any one of Items 6-8, wherein the coverage enhancing device comprises a first circulator, and wherein the first signal is configured to pass through the first circulator.

Item 10: Coverage enhancing device of Item 9, wherein the coverage enhancing device comprises a second circulator, wherein the first signal is configured to, after passing through the first circulator, pass through the second circulator.

Item 11 : Coverage enhancing device of any one of Items 1 -5, wherein: the first antenna input is a first antenna on a first array; and the first antenna output is a second antenna on a second array.

Item 12: Coverage enhancing device of Item 11 , wherein: the second antenna input is a third antenna on the first array; and the second antenna output is a fourth antenna on the second array.

Item 13: Coverage enhancing device of Item 12, wherein the first antenna is connected to the second antenna, and wherein the third antenna is connected to the fourth antenna.

Item 14. Coverage enhancing device of any one of Items 1-8, 11 , 12 and13, wherein the coverage enhancing device does not comprise a circulator.

Item 15. Coverage enhancing device of any one of the preceding Items, wherein the coverage enhancing device is a reciprocal coverage enhancing device.

Item 16. Coverage enhancing device of any one of the preceding Items, wherein the coverage enhancing device is configured to split the first signal into at least two first signals and/or split the second signal into at least two second signals.

Item 17. Coverage enhancing device of Item 16, wherein the at least two first signals have different directionality and/or wherein the at least two second signals have different directionality.

Item 18: A coverage enhancing device comprising: a plurality of antennas arranged on the coverage enhancing device; wherein at least some antennas of the plurality of antennas are spaced apart irregularly on the coverage enhancing device; and wherein the plurality of antennas is configured to reduce parasitic reflections of the coverage enhancing device.

Item 19: Coverage enhancing device of Item 18, wherein each of the plurality of antennas is spaced irregularly.

Item 20: Coverage enhancing device of any one of Items 18-19, wherein the at least some antennas of the plurality of antennas are spaced apart along a z-axis with respect to the coverage enhancing device.

The use of the terms “first”, “second”, “third” and “fourth”, “primary”, “secondary”, “tertiary” etc. does not imply any particular order, but are included to identify individual elements. Moreover, the use of the terms “first”, “second”, “third” and “fourth”, “primary”, “secondary”, “tertiary” etc. does not denote any order or importance, but rather the terms “first”, “second”, “third” and “fourth”, “primary”, “secondary”, “tertiary” etc. are used to distinguish one element from another. Note that the words “first”, “second”, “third” and “fourth”, “primary”, “secondary”, “tertiary” etc. are used here and elsewhere for labelling purposes only and are not intended to denote any specific spatial or temporal ordering. Furthermore, the labelling of a first element does not imply the presence of a second element and vice versa.

It may be appreciated that the figures comprise some circuitries or operations which are illustrated with a solid line and some circuitries or operations which are illustrated with a dashed line. Circuitries or operations which are comprised in a solid line are circuitries or operations which are comprised in the broadest example. Circuitries or operations which are comprised in a dashed line are examples which may be comprised in, or a part of, or are further circuitries or operations which may be taken in addition to circuitries or operations of the solid line examples. It should be appreciated that these operations need not be performed in order presented. Furthermore, it should be appreciated that not all of the operations need to be performed. The example operations may be performed in any order and in any combination.

It is to be noted that the word "comprising" does not necessarily exclude the presence of other elements or steps than those listed.

It is to be noted that the words “a” or “an” preceding an element do not exclude the presence of a plurality of such elements.

It should further be noted that any reference signs do not limit the scope of the claims, that the examples may be implemented at least in part by means of both hardware and software, and that several “means”, “units” or “devices” may be represented by the same item of hardware.

The various example methods, devices, nodes and systems described herein are described in the general context of method steps or processes, which may be implemented in one aspect by a computer program product, embodied in a computer- readable medium, including computer-executable instructions, such as program code, executed by computers in networked environments. A computer-readable medium may include removable and non-removable storage devices including, but not limited to, Read Only Memory (ROM), Random Access Memory (RAM), compact discs (CDs), digital versatile discs (DVD), etc. Generally, program circuitries may include routines, programs, objects, components, data structures, etc. that perform specified tasks or implement specific abstract data types. Computer-executable instructions, associated data structures, and program circuitries represent examples of program code for executing steps of the methods disclosed herein. The particular sequence of such executable instructions or associated data structures represents examples of corresponding acts for implementing the functions described in such steps or processes.

Although features have been shown and described, it will be understood that they are not intended to limit the claimed disclosure, and it will be made obvious to those skilled in the art that various changes and modifications may be made without departing from the scope of the claimed disclosure. The specification and drawings are, accordingly, to be regarded in an illustrative rather than restrictive sense. The claimed disclosure is intended to cover all alternatives, modifications, and equivalents.

Claims

1 . A coverage enhancing device (100) comprising: a first antenna input (102) configured to receive a first signal (101); a second antenna input (104) configured to receive a second signal (103); a first antenna output (106) configured to output the first signal (101); and a second antenna output (108) configured to output the second signal (103); wherein a relative arrangement of the first antenna input (102) and the first antenna output (106) is different from a relative arrangement of the second antenna input (104) and the second antenna output (108).

2. Coverage enhancing device of claim 1 , wherein the coverage enhancing device (100) is configured to phase shift the first signal (101 ) and/or the second signal (103).

3. Coverage enhancing device of claim 1 or claim 2, wherein the coverage enhancing device (100) is configured to increase a power density of the first signal (101 ) and/or the second signal (103).

4. Coverage enhancing device of any one of the preceding claims, wherein the relative arrangement of the first antenna input (102) and the first antenna output (106) being different from the relative arrangement of the second antenna input (104) and the second antenna output (106) comprises: the first antenna input (102) having a first position relative to the second antenna input (104); and the first antenna output (106) having a second position relative to the second antenna output (108); wherein the second position relative to the second antenna output (108) is different than the first position relative to the second antenna input (104).

5. Coverage enhancing device of any one of the preceding claims, wherein the relative arrangement of the first antenna input (102) and the first antenna output (106) being different from the relative arrangement of the second antenna input (104) and the second antenna output (108) comprises the relative arrangement being different in one or more of: an x-direction, a y-direction, and a z-direction.

6. Coverage enhancing device of any one of the preceding claims, wherein: the first antenna input (102) is a first antenna on a first array (120); and the first antenna output (106) is a second antenna on the first array (120).

7. Coverage enhancing device of claim 6, wherein the second antenna input (104) is the second antenna.

8. Coverage enhancing device of claim 6, wherein the second antenna input (104) is a third antenna.

9. Coverage enhancing device of any one of claims 6-8, wherein the coverage enhancing device 600 comprises a first circulator (312), and wherein the first signal (101 ) is configured to pass through the first circulator (312).

10. Coverage enhancing device of claim 9, wherein the coverage enhancing device 300 comprises a second circulator (316), wherein the first signal (101) is configured to, after passing through the first circulator (312), pass through the second circulator (316).

11. Coverage enhancing device of any one of claims 1-5, wherein: the first antenna input (102) is a first antenna on a first array (120); and the first antenna output (106) is a second antenna on a second array (122).

12. Coverage enhancing device of claim 11 , wherein: the second antenna input (104) is a third antenna on the first array (120); and the second antenna output (108) is a fourth antenna on the second array (122).

13. Coverage enhancing device of claim 12, wherein the first antenna is connected to the second antenna, and wherein the third antenna is connected to the fourth antenna.

14. Coverage enhancing device of any one of claims 1-8,11 , 12, and 13, wherein the coverage enhancing device (500) does not comprise a circulator.

15. Coverage enhancing device of any one of the preceding claims, wherein the coverage enhancing device (100) is a reciprocal coverage enhancing device.

16. Coverage enhancing device of any one of the preceding claims, wherein the coverage enhancing device (600) is configured to split the first signal (101) into at least two first signals (101 A, 101 B) and/or split the second signal (103) into at least two second signals (103A, 103B).

17. Coverage enhancing device of claim 16, wherein the at least two first signals (101 A, 101 B) have different directionality and/or wherein the at least two second signals (103A, 103B) have different directionality.

18. A coverage enhancing device (100) comprising: a plurality of antennas arranged on the coverage enhancing device (100); wherein at least some antennas of the plurality of antennas are spaced apart irregularly on the coverage enhancing device; and wherein the plurality of antennas is configured to reduce parasitic reflections of the coverage enhancing device.

19. Coverage enhancing device of claim 18, wherein each of the plurality of antennas is spaced irregularly.

20. Coverage enhancing device of any one of claims 18-19, wherein the at least some antennas of the plurality of antennas are spaced apart along a z-axis with respect to the coverage enhancing device (100).