Patent Description:
Millimeter waves (mmWaves) corresponding to carrier frequencies above <NUM> have been introduced for the new radio (NW) air interface as used in fifth generation (<NUM>) telecommunication systems. However, communication over mmWaves are sensible to blocking, i.e. physical objects blocking the radio waves. Although the blocking itself might be unavoidable, there are means that can be introduced that reduce the effects of the blocking. One such means is the use of smart radio environments. One technique enabling the creation of such smart radio environments involves the use of surfaces that can interact with the radio environment. This is illustrated in <FIG> shows a communications network <NUM> where a network node <NUM> is configured to communicate with a user equipment <NUM>. The network node <NUM> might be a radio access network node, radio base station, base transceiver station, node B (NB), evolved node B (eNB), gNB, access point (AP), access node, or integrated access and backhaul (IAB) node. The user equipment <NUM> might be a portable wireless device, mobile station, mobile phone, handset, wireless local loop phone, smartphone, laptop computer, tablet computer, wearable electronic device, Internet-of Things (IoT) device, network equipped sensor, or network equipped vehicle.

In the illustrative example of <FIG>, the line of sight signal path corresponding to communication channel 140a is blocked by a physical object 150a. An intelligent reconfigurable surface <NUM> is provided at physical object 150b such that the signal from network node <NUM> reaches user equipment <NUM> via the non-line of sight signal path corresponding to communication channel 140b.

As disclosed in, for example, "<NPL>), "<NPL>), and "<NPL> such surfaces are commonly called intelligent reconfigurable surfaces (IRS), meta-surfaces, reconfigurable intelligent surfaces, large intelligent surfaces. Without loss of generality or discrimination between these terms, the term IRS will be used throughout this disclosure.

Examples of IRS-aided wireless communication systems are disclosed in the following prior art documents:.

For communication in the far-field of the electromagnetic field (EM) around the IRS, the directions of expected wave propagation for each of the element of the IRS are parallel with almost equal distance. Equal distance implies that the path losses and the phase of the EM at all the elements are same and thus added constructively. Generally, the IRS has a comparatively large surface, compared to the surface of an antenna array of a traditional network node. Therefore, the far-field will be located further away from the IRS compared to a traditional network node. This will imply that the user equipment in some operational conditions will be in the near-field of the IRS. When the user equipment is in the near-field, the directions of expected wave propagation at the elements of the IRS will no longer be parallel. Additionally, the distance between each element of the IRS and the user equipment will be different. This negatively affects the communication channel between the network node and the user equipment. As a result, the collective signal at the user equipment will be uncontrolled and the received power at the user equipment will be sensitive to a slight change in position of the user equipment. In the worst case, the communication via the IRS between the network node and the user equipment is interrupted when the user equipment is located in the near-field of the IRS.

Hence, there is a need for enabling the communication between the network node and the user equipment to be maintained when the user equipment is located in the near-field of the IRS.

An object of embodiments herein is to provide a method, a controller, a computer program, and a computer program product that address the above issues.

According to a first aspect there is presented a method for adjusting atoms of an IRS. The method is performed by a controller. The controller is configured to control the IRS. The IRS comprises an array of the atoms. Each of the atoms has an individually adjustable phase shift and gain. At least some of the atoms are provided with a measurement sensor. The method comprises obtaining, from the measurement sensors, measurements of received power of a signal transmitted from a user equipment and received by the atoms. The method comprises determining, by a gradient in received power between two of the measurement sensors is larger than a threshold value, that the user equipment is in near-field of the IRS. The method comprises, as a result thereof, adjusting the phase shift of a first subset of the atoms for reflection at the IRS of subsequent communication between a network node and the user equipment when the user equipment is in the near-field of the IRS.

According to a second aspect there is presented a controller for adjusting atoms of an IRS. The controller is configured to control the IRS. The IRS comprises an array of the atoms. Each of the atoms has an individually adjustable phase shift and gain. At least some of the atoms are provided with a measurement sensor. The controller comprises processing circuitry. The processing circuitry is configured to cause the controller to obtain, from the measurement sensors, measurements of received power of a signal transmitted from a user equipment and received by the atoms. The processing circuitry is configured to cause the controller to determine, by a gradient in received power between two of the measurement sensors is larger than a threshold value, that the user equipment is in near-field of the IRS. The processing circuitry is configured to cause the controller to, as a result thereof, adjust the phase shift of a first subset of the atoms for reflection at the IRS of subsequent communication between a network node and the user equipment when the user equipment is in the near-field of the IRS.

According to a third aspect there is presented a controller for adjusting atoms of an IRS. The controller is configured to control the IRS. The IRS comprises an array of the atoms. Each of the atoms has an individually adjustable phase shift and gain. At least some of the atoms are provided with a measurement sensor. The controller comprises an obtain module configured to obtain, from the measurement sensors, measurements of received power of a signal transmitted from a user equipment and received by the atoms. The controller comprises a determine module configured to determine, by a gradient in received power between two of the measurement sensors is larger than a threshold value, that the user equipment is in near-field of the IRS. The controller comprises an adjust module configured to, as a result thereof, adjust the phase shift of a first subset of the atoms for reflection at the IRS of subsequent communication between a network node and the user equipment when the user equipment is in the near-field of the IRS.

According to a fourth aspect there is presented a computer program for adjusting atoms of an IRS, the computer program comprising computer program code which, when run on a controller, causes the controller to perform a method according to the first aspect.

According to a fifth aspect there is presented a computer program product comprising a computer program according to the fourth aspect and a computer readable storage medium on which the computer program is stored. The computer readable storage medium could be a non-transitory computer readable storage medium.

Advantageously these aspects resolve the above issues.

Advantageously these aspects enable the communication between the network node and the user equipment to be maintained when the user equipment is located in the near-field of the IRS.

As noted above there is a need for enabling the communication between the network node and the user equipment to be maintained when the user equipment is located in the near-field of the IRS.

In one example the IRS consists of arrays of passive patch antennas also denoted passive elements, where each patch antenna/element comprises an atom. The embodiments disclosed herein relate to mechanisms for adjusting atoms of an IRS. In order to obtain such mechanisms there is provided a controller, a method performed by the controller, a computer program product comprising code, for example in the form of a computer program, that when run on the controller, causes the controller to perform the method.

The IRS <NUM> comprises an array of elements, each comprising an atom, extending in the azimuth and the elevation directions. The locations of each element (or relative distance between the elements) are known. In some examples, the elements are equally spaced in azimuth and the elevation directions. Each element may have a setup to adjust the phase and gain of the reflected signal to create desire beam at the IRS <NUM>. Additionally, each element is having termination so the amplitude of the reflected signal to be controlled.

<FIG> schematically illustrates an IRS <NUM> comprising two types of elements 121a, 121b, where each element 121a, 121b comprises an atom. An IRS <NUM> comprising an array of elements 121a, 121b thus comprises an array of atoms (see <FIG>). A controller <NUM> is configured to, by means of adapting the individual phase shift and/or gain of each atom, control the reflection angle of the IRS <NUM>, and thus how the signal path corresponding to communication channel 140b is reflected at the IRS <NUM>. In this respect, the atoms are not connected to active radio transceivers (i.e., devices capable to modulate data streams up to radio frequency and demodulate radio frequencies to data streams). Instead, the atoms in the array are connected to resistors, inductors, and/or capacitors of which the electrical impedance is controllable, and where the atoms are connected to the resistors, inductors, and/or capacitors towards a ground plane such that the reflection phase of respective atoms can be adapted based on electrical impedance setting. Thus, by controlling the electrical impedances of the respective atoms, the reflection angle of an incoming electromagnetic wave can be adapted according to the generalized Snell's law. The IRS <NUM> might be part of, or operatively connected to, a network node.

Each of the elements 121a, 121b comprises an atom. In short, each of the second type of elements 121b comprises a measurement sensor whereas the first type of elements 121a do not comprise any measurement sensor. There could be different ways in which the first type of elements 121a and the second type of elements 121b are distributed in the array. According to a first example, the atoms provided with the measurement sensors are evenly distributed throughout the IRS <NUM>. According to a second example, the atoms provided with the measurement sensors are coarsely or randomly distributed throughout the IRS <NUM> (but still with known positions). Also further examples of how the first type of elements 121a and the second type of elements 121b could be distributed in the array are envisioned.

Particular details of the first type of element 121a will be disclosed next with reference to <FIG> and particular details of the second type of element 121b will be disclosed next with reference to <FIG>.

<FIG> schematically illustrates the first type of element 121a of the IRS <NUM> according to an embodiment. The first type of element 121a comprises an atom <NUM> that is connected to ground via a phase shifter <NUM> and an impedance adjuster <NUM>. The phase shifter <NUM> is configured to introduce a delay between the incident signal and reflected signal out from the atom <NUM>. The phase can thereby be controlled to create a beam for the reflected signal, thus determining the refection angle and creating a beam pattern for the reflected signal. The impedance adjuster <NUM> is configured to adjust the gain of the reflected signal. The gain can thereby be controlled by varying the load impedance to create a beam pattern or to mute the atom <NUM>, by setting the matched load. The amount of phase shift to be applied by the phase shifter <NUM> and the amount of gain to be applied by the impedance adjuster <NUM> are controlled by the controller <NUM>.

<FIG> schematically illustrates the second type of element 121b of the IRS <NUM> according to an embodiment. The second type of element 121b comprises an atom <NUM> that is connected to ground via a phase shifter <NUM>, a measurement sensor <NUM>, and an impedance adjuster <NUM>. In turn, the measurement sensor <NUM> comprises a probe and a rectifier. The measurement sensor <NUM> is configured to measure the received signal at the atom <NUM> from the user equipment. The probe will act as a coupler to couple a small amplitude signal. The probe is connected to a rectifier and thus a direct current (DC) voltage can be measured, which will give information of received power of the received signal at that element. The probe could be placed at a known position, e.g. the reflecting load for variable gain adjustment. This might aid to minimize dependency to the different phase and gain setting of the element.

<FIG> is a flowchart illustrating embodiments of methods for adjusting atoms <NUM> of an IRS <NUM>. The methods are performed by the controller <NUM>. The methods are advantageously provided as computer programs <NUM>. The controller <NUM> is configured to control the IRS <NUM>. The IRS <NUM> comprises an array of atoms <NUM>. Each of the atoms <NUM> has an individually adjustable phase shift and gain. At least some of the atoms <NUM> are provided with a measurement sensor <NUM>.

S102: The controller <NUM> obtains, from the measurement sensors <NUM>, measurements of received power of a signal transmitted from a user equipment <NUM> and received by the atoms <NUM>.

When the user equipment <NUM> is in the near-field of the IRS <NUM>, the individual paths between the user equipment <NUM> and each of the atoms <NUM> of the IRS <NUM> will not be parallel and hence not be equally long (see <FIG> as referenced below for an illustration of this). Therefore, the distance between the user equipment <NUM> and the IRS <NUM> will vary considerably between different individual atoms <NUM> of the IRS <NUM> and thus the phase delay will vary considerably between different individual atoms <NUM> of the IRS <NUM>.

S104: The controller <NUM> determines, by a gradient in received power between two of the measurement sensors <NUM> being larger than a threshold value, that the user equipment <NUM> is in the near-field of the IRS <NUM>.

S106: The controller <NUM> as a result thereof (i.e., as a result of having determined that the user equipment <NUM> is in the near-field of the IRS <NUM>) adjusts the phase shift of a first subset of the atoms <NUM> for reflection at the IRS <NUM> of subsequent communication between a network node <NUM> and the user equipment <NUM> when the user equipment <NUM> is in the near-field of the IRS <NUM>.

Hence, there is provided a method where a user equipment <NUM> is identified to be in the near-field of the IRS <NUM> with or without assistance from the user equipment <NUM>. If the controller <NUM> determines the user equipment <NUM> to be in the near-field the IRS <NUM>, the atoms <NUM> of the IRS <NUM> are at least phase-wise adjusted so that the phase of signals received at the atoms <NUM> are within reasonable range, thereby enabling the user equipment <NUM> to communicate with the network node <NUM> via the IRS <NUM> even in the near-field of the IRS <NUM>.

Embodiments relating to further details of adjusting atoms <NUM> of an IRS <NUM> as performed by the controller <NUM> will now be disclosed.

In some aspects, not only a phase shift is applied but also the gain of at least some of the atoms <NUM> is adjusted. In particular, in some embodiments, some atoms <NUM> are muted. Hence, according to an embodiment, the controller <NUM> is configured to perform (optional) step S108:
S108: The controller <NUM> mutes (as a result of having determined that the user equipment <NUM> is in the near-field of the IRS <NUM>) a second subset of the atoms <NUM> for reflection at the IRS <NUM> of the subsequent communication between the network node <NUM> and the user equipment <NUM>.

In general terms, the phase is adjusted for all atoms <NUM> whose gain is not adjusted, and vice versa. That is, in some embodiments, each of the atoms <NUM> is either a member of the first subset or the second subset but not both. Hence, once the members of one of the subsets have been identified, also the members of the other one of the subsets are automatically identified.

There could be different ways for the controller <NUM> to select which atoms <NUM> to have the phase shift adjusted, i.e. to determine which atoms <NUM> to be part of the first subset. In some aspects, the selection is made with respect to the variation of angle of arrival.

<FIG> show examples in terms of received power and phase delay variation, respectively, as a function of atom position of an IRS where the user equipment is in the near-field of the IRS. The examples are the result of simulation of an IRS with <NUM> atoms where the atoms are arranged in a <NUM>-by-<NUM> array. In the array all atoms equally spaced apart such that their centers are separated by <NUM>. For the simulation the user equipment is located at the center position of the array and <NUM> away from the array. In <FIG> the circles of lines with different thickness represent the relative power levels at each position of the atoms; the thicker the line, the higher the relative power levels. The thickest line represents a relative power level of about <NUM> dB whereas the thinnest line represents about <NUM> dB. From <FIG> thus follows that the difference between the received power among atoms at the center of the array and at edges of the array is more than <NUM> dB. In <FIG> the circles of lines with different thickness represent the relative phase delay at each position of the atoms; the thicker the line, the higher the relative phase delay. The thickest line represents a relative phase delay of about <NUM> times 2π whereas the thinnest line represents about <NUM> times 2π. From <FIG> thus follows that the difference between the phase delay among atoms at the center of the array and at edges of the array is almost <NUM> times 2π (since the difference between <NUM> times 2π and <NUM> times 2π is <NUM> times 2π).

In particular, in some embodiments, the atoms <NUM> in the first subset all yield an adjustment of the phase shift within a predefined interval and maximize number of members in the first subset subject to a power maximization criterion. The members of the first subset could thus be selected as those atoms <NUM> for which the variation of angle of arrival is within the predefined interval in combination with the condition to either maximize the number of members in the first subset or the atoms <NUM> that yield maximum total power, Pmax. In this respect, the maximum total power can be expressed as: <MAT> where N are the total number of elements in the IRS, where j is the imaginary unit, i.e., j<NUM> = -<NUM>, where Ai is the simulated or measured power of element i, where θi is the simulated phase component of element i, and where <MAT>.

Similarly, the members of the second subset could be selected as those atoms <NUM> for which the variation of angle of arrival is not within the predefined interval. That is, in some embodiments, none of the atoms <NUM> in the second subset yield an adjustment of the phase shift within the predefined interval.

<FIG> at (a) shows an example of which number of selected elements that yields maximum power as a function of elements selected within a distance D, in units of 2π, from the element yielding highest received power, and at (b) shows the summed total power for the selected elements as a function of elements selected within a distance D, in units of 2π from the element yielding highest received power. As seen in the figure, both the number of elements and the corresponding summed total power first increase and then decrease as a function of the distance D from the element yielding highest received power.

<FIG> shows an example of element positions of an IRS and which elements are selected to be active when a user equipment is in the near-field of the IRS. The examples are the result of simulation of an IRS with <NUM> atoms where the atoms are arranged in a <NUM>-by-<NUM> array. In the array all atoms equally spaced apart such that their centers are separated by <NUM>. For the simulation the user equipment is located at the center position of the array and <NUM> away from the array. This selection of elements for the given simulation ensures that, with proper phase adjustment, the combination of elements will ensure maximum power transfer in the near-field.

There could be different predefined intervals. In general terms, the boundaries of the predefined interval will depend on the general design of the elements 121a, 121b and how the phase shift can be implemented. If the elements 121a, 121b comprises phase shifters <NUM> then a signal reflected by the IRS will pass the phase shifters <NUM> twice; once when incoming and once when being reflected. Then the range could be [<NUM>, 4π]. The range could have different end-points for other implementations of the elements 121a, 121b. In some non-limiting examples, the predefined interval is either [<NUM>, 2π], or [<NUM>, 4π]. That is, according to this example, all atoms for which the phase shift should be shifted by a value in the range [<NUM>, 2π] or [<NUM>, 4π] would be selected to be part of the first subset. In some embodiments, the predefined interval is related to the duration of the cyclic prefix (CP) duration used.

In some embodiments, the gradient in received power, as used in step S104, is obtained in terms of an angle of arrival value of the signal transmitted from the user equipment <NUM>. Further aspects of this will now be disclosed with reference to <FIG> schematically illustrates an IRS <NUM> having two atoms 122a, 122b whose centers are separated by a distance D in the y direction. According to <FIG>, the atoms 122a and 122b are in the xy plane. A user equipment <NUM> is located perpendicular to the xy plane with respect to atom 122a and is in the z direction with respect to the atoms 122a, 122b. The user equipment <NUM> is assumed to provide relatively isotropic radiation with respect to the atoms 122a, 122b. The distance between atom 122a and user equipment <NUM> is R<NUM> and the distance between atom 122b and user equipment <NUM> is R<NUM>. R<NUM> and R<NUM> are thus in an angle θ with respect to each other. As R<NUM> is smaller than R<NUM>, the received power, denoted P<NUM>, at atom 122a, is larger than the received power, denoted P<NUM>, at atom 122b. When the value of the angle θ is larger than a threshold angle, user equipment <NUM> is defined to be in the near-field of the IRS <NUM>. The threshold angle can be calculated based on the tolerated power variation among to selected atoms and thus be user-defined. Hence, in some embodiments, the threshold value is dependent on tolerated power variation among the atoms <NUM>. In other embodiments, the threshold value is dependent on how much the atoms <NUM> from which the measurements of received power were made by the measurement sensors <NUM> are distanced from each other and dimension of the IRS <NUM>. A numerical value for the threshold angle can be computed from <FIG> (which will be described in further detail below). For example, with reference to <FIG>, assume that <NUM> dB is set as the tolerance level of the power variation and that the IRS has a diagonal length of <NUM>. Assume further that the user equipment is closest to the center-most element. Assume further that the difference in received power between the center-most element and an element at a distance of <NUM> is <NUM> dB. This corresponds to that the user equipment is distanced <NUM> from the center-most element and thus an angle of arrival to the element at a distance of <NUM> from the center-most element of <NUM>°. Hence, the threshold angle for this example is <NUM>°.

From the Friis equation, the power is inversely proportional to the square of the distance. That is: <MAT>.

Further, from the Pythagorean theorem follows that: <MAT>.

Substituting R<NUM> in the expression for the power ratios with <MAT> yields: <MAT>.

Still further, from the assumptions in <FIG> follows that: <MAT>.

It then follows that the angle of arrival value, defined by θ, can be determined as: <MAT> where P<NUM> thus is the measurement of received power obtained from a measurement sensor at atom 122a and where P<NUM> thus is the measurement of received power obtained from a measurement sensor at atom 122b. As noted above, the IRS <NUM> generally comprises an array of elements, each comprising its own atom, and where some of the elements comprises a measurement sensor. There could then be different ways to select from which sensors the measurement of received power should be obtained. In some embodiments, P<NUM> is the highest of all the obtained measurements of received power and P<NUM> is one of the obtained measurements of received power that is more than a threshold lower than P<NUM> but still higher than a noise floor.

In some aspects, how much the phase shift is adjusted is proportional to the gradient in received power. Further, the angle of arrival value, defined by θ, can be utilized during the adjustment of the phase shift. In particular, the phase shift can be adjusted by a compensation factor Δφ that is a function of the angle of arrival value. Assume that the signal transmitted from the user equipment <NUM> has a wavelength λ, that the atoms <NUM> from which the measurements of received power were made by the measurement sensors <NUM> are separated a distance D, and that the phase shift is adjusted by a compensation factor Δφ. Then, in some embodiments, the compensation factor Δφ is determined according to: <MAT>.

<FIG> shows the power difference, in dB, from the maximum received power as a function of the distance between the user equipment <NUM> and the IRS <NUM> for different dimensions of the IRS <NUM>. As can be seen in the figure, the difference increases as the user equipment <NUM> is moved closer to the IRS <NUM> and as the size of the IRS increases. The maximum received power will be at the element which has the shortest distance to the user equipment <NUM> when the user equipment <NUM> is perpendicular to the array of elements. The larger the IRS <NUM> is, the larger the near-field will be. Whether the user equipment <NUM> is in the near-field or not can be detected by monitoring this power difference for a given distance.

<FIG> is a flowchart of a method for adjusting atoms <NUM> of an IRS <NUM> as performed by the controller <NUM>, and in particular to identify if the user equipment <NUM> is in the near-field of the IRS <NUM> or not.

S201: Measurements of received power of a signal transmitted from the user equipment <NUM> and received by the atoms <NUM> are obtained from the measurement sensors <NUM>
S202: The element corresponding to the atom where the maximum amount of power was received is identified. This amount of power is denoted P<NUM>.

S203: An element at a distance D from the element in step S202 is identified. The amount of power from the atom at this element is denoted P<NUM>.

S204: It is determined, by comparing a gradient in received power, in terms of a difference between P<NUM> and P<NUM>, to a threshold value, whether the user equipment <NUM> is in the near-field of the IRS <NUM> or not.

S205: If the gradient is larger than the threshold value the user equipment <NUM> is in the near-field of the IRS <NUM> and step S207 is entered. Else step S206 is entered.

S206: The user equipment <NUM> is in the far-field of the IRS <NUM>. No further adjustment of the IRS <NUM> is required. Step S201 can then be entered again.

S207: A first subset of the atoms identified that yield an adjustment of the phase shift within a predefined interval and that maximize the number of members in the first subset subject to a power maximization criterion.

S208: Phase shift differences for the atoms in the first subset are estimated.

S209: The phase shift of the first subset of the atoms <NUM> is adjusted for reflection at the IRS <NUM> during subsequent communication between a network node <NUM> and the user equipment <NUM>.

S210: Gain equalization is performed based on a measured gain variation between the atoms in the first subset.

S211: A second subset of the atoms <NUM> composed of those atoms <NUM> that are not part of the first subset are muted for reflection at the IRS <NUM> during the subsequent communication between the network node <NUM> and the user equipment <NUM>. Step S201 can then be entered again.

Aspects of the user equipment <NUM> will now be disclosed. The user equipment <NUM> might be equipped with one or more antenna arrays, where each of the one or more antenna array comprises one or more individual elements, each element comprising an atom. The user equipment <NUM> might thereby be configured for beamforming. In case the user equipment <NUM> either by itself or by obtaining an indication from another entity, such as from the IRS <NUM> or controller <NUM> via the network node <NUM>, determines that the user equipment <NUM> is in the near-field of the IRS <NUM>, the user equipment <NUM> might form a wide beam, or an omni-directional beam. For example, the user equipment <NUM> might by itself determine that it is in the near-field of the <NUM><NUM> when a variation in received power (between two individual elements, or atoms) is above a threshold value.

<FIG> schematically illustrates, in terms of a number of functional units, the components of a controller <NUM> according to an embodiment. Processing circuitry <NUM> is provided using any combination of one or more of a suitable central processing unit (CPU), multiprocessor, microcontroller, digital signal processor (DSP), etc., capable of executing software instructions stored in a computer program product <NUM> (as in <FIG>), e.g. in the form of a storage medium <NUM>. The processing circuitry <NUM> may further be provided as at least one application specific integrated circuit (ASIC), or field programmable gate array (FPGA).

Particularly, the processing circuitry <NUM> is configured to cause the controller <NUM> to perform a set of operations, or steps, as disclosed above. For example, the storage medium <NUM> may store the set of operations, and the processing circuitry <NUM> may be configured to retrieve the set of operations from the storage medium <NUM> to cause the controller <NUM> to perform the set of operations.

Thus the processing circuitry <NUM> is thereby arranged to execute methods as herein disclosed. The controller <NUM> may further comprise a communications interface <NUM> at least configured for communications with the IRS <NUM>. As such the communications interface <NUM> may comprise one or more transmitters and receivers, comprising analogue and digital components. The processing circuitry <NUM> controls the general operation of the controller <NUM> e.g. by sending data and control signals to the communications interface <NUM> and the storage medium <NUM>, by receiving data and reports from the communications interface <NUM>, and by retrieving data and instructions from the storage medium <NUM>. Other components, as well as the related functionality, of the controller <NUM> are omitted in order not to obscure the concepts presented herein.

<FIG> schematically illustrates, in terms of a number of functional modules, the components of a controller <NUM> according to an embodiment. The controller <NUM> of <FIG> comprises a number of functional modules; an obtain module 210a configured to perform step S102, a determine module 210b configured to perform step S104, and an adjust module 210c configured to perform step S106. The controller <NUM> of <FIG> may further comprise a number of optional functional modules, such a mute module 210d configured to perform step S108. In general terms, each functional module 210a:210e may in one embodiment be implemented only in hardware and in another embodiment with the help of software, i.e., the latter embodiment having computer program instructions stored on the storage medium <NUM> which when run on the processing circuitry makes the controller <NUM> perform the corresponding steps mentioned above in conjunction with <FIG>. It should also be mentioned that even though the modules correspond to parts of a computer program, they do not need to be separate modules therein, but the way in which they are implemented in software is dependent on the programming language used. Preferably, one or more or all functional modules 210a:210e may be implemented by the processing circuitry <NUM>, possibly in cooperation with the communications interface <NUM> and/or the storage medium <NUM>. The processing circuitry <NUM> may thus be configured to from the storage medium <NUM> fetch instructions as provided by a functional module 210a:210e and to execute these instructions, thereby performing any steps as disclosed herein.

The controller <NUM> may be provided as a standalone device or as a part of at least one further device. For example, the controller <NUM> may be part of, integrated with, or collocated with, the IRS <NUM>. Alternatively, functionality of the controller <NUM> may be distributed between at least two devices, or nodes. A first portion of the instructions performed by the controller <NUM> may be executed in a first device, and a second portion of the of the instructions performed by the controller <NUM> may be executed in a second device; the herein disclosed embodiments are not limited to any particular number of devices on which the instructions performed by the controller <NUM> may be executed. Hence, the methods according to the herein disclosed embodiments are suitable to be performed by a controller <NUM> residing in a cloud computational environment. Therefore, although a single processing circuitry <NUM> is illustrated in <FIG> the processing circuitry <NUM> may be distributed among a plurality of devices, or nodes. The same applies to the functional modules 210a:210e of <FIG> and the computer program <NUM> of <FIG>.

Claim 1:
A method for adjusting atoms (<NUM>) of an intelligent reflective surface, IRS (<NUM>), the method being performed by a controller (<NUM>), the controller (<NUM>) being configured to control the IRS (<NUM>), the IRS (<NUM>) comprising an array of the atoms (<NUM>), wherein each of the atoms (<NUM>) has an individually adjustable phase shift and gain, and wherein at least some of the atoms (<NUM>) are provided with a measurement sensor (<NUM>), the method comprising:
obtaining (S102), from the measurement sensors (<NUM>), measurements of received power of a signal transmitted from a user equipment (<NUM>) and received by the atoms (<NUM>);
determining (S104), by a gradient in received power between two of the measurement sensors (<NUM>) being larger than a threshold value, that the user equipment (<NUM>) is in near-field of the IRS (<NUM>); and as a result thereof:
adjusting (S106) the phase shift of a first subset of the atoms (<NUM>) for reflection at the IRS (<NUM>) of subsequent communication between a network node (<NUM>) and the user equipment (<NUM>) when the user equipment (<NUM>) is in the near-field of the IRS (<NUM>).