Method and apparatus for enhancing power of signals using IRS in wireless communication system

Abstract

A method for enhancing received signal power at a receiver is provided. The method includes estimating channel gains by transmitting pilot signals to the receiver via each antenna of a plurality of antennas of a transmitter and an IRS, determining an antenna selection metric based on the channel gains when transmitting the pilot signals to the receiver via each antenna of the transmitter and the IRS, identifying an antenna from the plurality of antennas that provides a maximum antenna selection metric, determining reflection coefficients for each reflector of the IRS based on the identified antenna, configuring reflectors of the IRS with the reflection coefficients, and transmitting signals to the receiver via the identified antenna and the configured reflectors.

Description

Technical Field

[0001] This disclosure relates to a wireless communication system. More specifically, this disclosure relates to a method and apparatus for using a smart reflective surface (IRS) in a wireless communication system to enhance the power of a signal. Background Technology

[0002] Considering the evolution of wireless communication generation after generation, the technology has consistently been developed primarily for human-facing services such as voice calls, multimedia services, and data services. Following the commercialization of 5G (fifth-generation) communication systems, the number of connected devices is expected to grow exponentially. Increasingly, these devices will connect to communication networks. Examples of connected things can include vehicles, robots, drones, home appliances, displays, smart sensors connected to various infrastructures, construction machinery, and factory equipment. Mobile devices are expected to evolve in various form factors, such as augmented reality glasses, virtual reality headsets, and holographic devices. Efforts are underway to develop improved 6G communication systems to provide a wide range of services by connecting hundreds of billions of devices and things in the 6G (sixth-generation) era. For these reasons, 6G communication systems are referred to as "beyond 5G" systems.

[0003] The 6G communication system, expected to be commercialized around 2030, will have peak data rates in the Tera (1,000 gigabits) range and wireless latency of less than 100 μsec, making it 50 times faster than 5G communication systems and with 1 / 10 of their wireless latency.

[0004] To achieve such high data rates and ultra-low latency, 6G communication systems have been considered for implementation in the terahertz band (e.g., the 95 GHz to 3 THz band). It is anticipated that technologies capable of guaranteeing signal transmission distance (i.e., coverage) will become more important, as path loss and atmospheric absorption in the terahertz band are more severe than those introduced in the mmWave band in 5G. As a primary technology for guaranteeing coverage, it is necessary to develop radio frequency (RF) components, antennas, and novel waveforms that offer better coverage compared to orthogonal frequency division multiplexing (OFDM), beamforming and massive MIMO, full-dimensional MIMO (FD-MIMO), array antennas, and multi-antenna transmission technologies such as massive MIMO. Furthermore, new technologies for improving the coverage of terahertz band signals, such as metamaterial-based lenses and antennas, orbital angular momentum (OAM), and reconfigurable smart surfaces (RIS), have been discussed.

[0005] Furthermore, to improve spectrum efficiency and overall network performance, the following technologies have been developed for 6G communication systems: full-duplex technology that enables uplink and downlink transmissions to use the same frequency resources simultaneously; network technologies for integrated utilization of satellites, high-altitude platform stations (HAPS), etc.; improved network architectures to support mobile base stations and enable network operation optimization and automation; dynamic spectrum sharing technology based on spectrum usage prediction with conflict avoidance; the use of artificial intelligence (AI) in wireless communication to improve overall network operation by leveraging AI from the design phase of 6G development and internalizing end-to-end AI support functions; and next-generation distributed computing technologies to overcome the limitations of UE computing capabilities through ultra-high-performance communication and computing resources accessible on the network, such as mobile edge computing (MEC) and the cloud. In addition, efforts continue to strengthen device connectivity, optimize networks, enhance the software-defined nature of network entities, and increase the openness of wireless communication by designing new protocols to be used in 6G communication systems, developing mechanisms for achieving hardware-based security environments and secure data use, and developing technologies for maintaining privacy.

[0006] Research and development on hyper-connectivity aspects of 6G communication systems, including human-to-machine (P2M) and machine-to-machine (M2M) connections, are anticipated to enable the next generation of hyper-connected experiences. In particular, services such as truly immersive extended reality (XR), high-fidelity mobile holograms, and digital replicas are expected to be provided via 6G communication systems. Furthermore, services such as remote surgery for enhanced security and reliability, industrial automation, and emergency response will be available through 6G communication systems, enabling the application of these technologies in various fields such as industry, healthcare, automotive, and home appliances.

[0007] Intelligent reflective surfaces (IRS) are envisioned as energy-efficient devices to assist sixth-generation (6G) wireless communication systems in delivering signals from transmitter to receiver. IRS are also known as reconfigurable intelligent surfaces (RIS). IRS do not contain active components like power-consuming radio frequency (RF) chains (e.g., amplifiers, mixers, filters, signal converters, etc.). Therefore, IRS consumes very little energy. An IRS is a digitally controlled meta-surface with many low-cost passive reflectors, such as phase shifters and printed dipoles, that reflect signals emitted from the transmitter toward the receiver to improve the power of the signal received at the receiver at a lower cost. However, when reflecting the signal toward the receiver, the IRS causes an amplitude / phase shift in the signal, which can be controlled by the IRS controller. The IRS reflector enables passive beamforming of the signal received from the transmitter to improve the power of the signal received at the receiver. Similar to IRS, transmit antenna selection (AS) is a conventional technique for improving energy and cost efficiency by reducing the number of RF chains at the transmitter. According to the transmit AS, the transmitter selects a subset of its antennas and connects them to the transmitter's available RF chains, the number of which is less than the number of the transmitter's antennas. The transmit AS achieves full diversity with fewer RF chains.

[0008] To improve the power of the signal received at the receiver, several techniques have been proposed to use passive beamforming at the transmit AS and IRS in conjunction with active beamforming at the transmitter (i.e., transmit beamforming). When active beamforming is performed, the transmitter must listen for channel changes between the transmitter and receiver due to reflections of the transmitted signal from the IRS. Furthermore, the IRS with passive beamforming needs to be configured with a reflection coefficient that maximizes the power of the signal received at the receiver.

[0009] In existing methods, local optima are developed while using alternating optimization techniques to minimize the transmit power at the transmitter. Currently, different optimization techniques exist to maximize the power of the signal received at the receiver. Fixed-point iterative methods are existing methods and techniques based on semi-infinite relaxation (SDR) that produce approximate solutions. Alternatively, manifold optimization techniques based on conjugate gradients, which improve performance compared to SDR-based techniques, converge to local optima. Furthermore, branch-and-bound methods, with manifold-based approaches, converge to global optima with performance close to optimal with lower computational complexity. All these existing methods involve the assumption of channel state information (CSI) at both the transmitter and the IRS, which is challenging to obtain due to the passive nature of the IRS reflector. Moreover, existing methods focus on beamforming at the transmitter, which requires multiple RF chains, the same number as the number of antennas used for transmission. Therefore, it is desirable to provide an optimal solution that maximizes the power of the signal received at the receiver by combining antenna subset selection and passive beamforming.

[0010] The above information is presented as background information only to aid in understanding this disclosure. It is neither determined nor asserted whether any of the foregoing items may be applicable as prior art to this disclosure. Summary of the Invention

[0011] Technical issues

[0012] Various aspects of this disclosure are intended to address at least the aforementioned problems and / or disadvantages and to provide at least the following advantages. Therefore, one aspect of this disclosure is to provide a method and apparatus for using an IRS to enhance the power of a signal received at a receiver. This method improves system performance at the transmitter with lower hardware cost by using passive beamforming at the IRS to assist transmit antenna selection (AS). System performance is improved by performing optimal antenna subset selection, transmit beamforming at the transmitter, and passive beamforming at the IRS to maximize the power of the signal received at the receiver.

[0013] Additional aspects will be set forth in part in the following description, and in part will be apparent from the specification, or may be learned by practice of the presented embodiments.

[0014] Technical solution

[0015] According to one aspect of this disclosure, a method is provided for enhancing the power of a signal received at a receiver in a wireless communication system using an IRS. The method includes: a transmitter of the wireless communication system estimating a channel gain by transmitting a pilot signal to the receiver via each of a plurality of antennas of the transmitter and the IRS; the transmitter determining an antenna selection metric based on the channel gain when transmitting the pilot signal to the receiver via each of the plurality of antennas of the transmitter and the IRS; the transmitter identifying an antenna from the plurality of antennas that provides the maximum antenna selection metric; the transmitter determining a reflection coefficient of each reflector of the IRS based on the identified antenna; the transmitter configuring the reflectors of the IRS with the reflection coefficients; and the transmitter transmitting a signal to the receiver via the identified antenna and the configured reflector.

[0016] According to another aspect of this disclosure, a method is provided for enhancing the power of a signal received at a receiver in a wireless communication system using an IRS. The method includes: the receiver estimating a channel gain by receiving pilot signals from each of a plurality of antennas of a transmitter of the wireless communication system and the IRS; the receiver determining an antenna selection metric based on the channel gain when receiving the pilot signals from each of the plurality of antennas of the transmitter and the IRS; the receiver identifying from the plurality of antennas an antenna that provides the maximum antenna selection metric; the receiver determining a reflection coefficient of each reflector of the IRS based on the identified antenna; and the receiver reporting the identified antenna and the reflection coefficient of each reflector to the transmitter to configure the reflectors of the IRS with the reflection coefficients and enable the transmitter to transmit signals via the identified antenna.

[0017] According to another aspect of this disclosure, a method for using an IRS to enhance the power of a signal received at a receiver in a wireless communication system. The method includes: a transmitter of the wireless communication system estimating a first channel gain by transmitting pilot signals to a receiver via each of a plurality of antennas of the transmitter and the IRS, wherein the reflection coefficient of each reflector of the IRS is set to zero; the transmitter estimating a second channel gain by transmitting the pilot signals to the receiver via each of the plurality of antennas and the IRS, wherein the reflection coefficient of each reflector of the IRS is set to one; the transmitter determining the difference between the second channel gain and the first channel gain for each antenna; the transmitter identifying the antenna among the plurality of antennas whose sum of the magnitude of the first channel gain and the magnitude of the difference between the second channel gain and the first channel gain is the largest; the transmitter determining the reflection coefficient of each reflector of the IRS by transmitting each pilot signal in a set of pilot signals via the identified antenna and the IRS, wherein the number of pilot signals in the set of pilot signals is equal to the number of reflectors in the IRS; and the transmitter transmitting signals to the receiver via the identified antenna and the IRS based on the reflection coefficients.

[0018] According to another aspect of this disclosure, a method is provided for using an IRS to enhance the power of a signal received at a receiver in a wireless communication system. The method includes: the receiver estimating a first channel gain by receiving pilot signals from each of a plurality of antennas of the transmitter of the wireless communication system and the IRS, wherein the reflection coefficient of each reflector of the IRS is set to zero; the receiver estimating a second channel gain by receiving the pilot signals from each of the plurality of antennas and the IRS, wherein the reflection coefficient of each reflector of the IRS is set to one; the receiver determining the difference between the second channel gain and the first channel gain for each antenna; the transmitter identifying the antenna among the plurality of antennas whose sum of the magnitude of the first channel gain and the magnitude of the difference between the second channel gain and the first channel gain is the largest; the receiver determining the reflection coefficient of each reflector of the IRS by receiving each pilot signal from the identified antenna and the set of pilot signals of the IRS, wherein the number of pilot signals in the set of pilot signals is equal to the number of reflectors in the IRS; and the receiver reporting the identified antenna and the reflection coefficient of each reflector to the transmitter so as to configure the reflectors of the IRS with the reflection coefficients and enable the transmitter to transmit signals via the identified antenna.

[0019] According to another aspect of this disclosure, a method is provided for enhancing the power of a signal received at a receiver in a wireless communication system using an IRS. The method includes: a transmitter of the wireless communication system estimating a channel gain by transmitting a pilot signal to the receiver via an antenna set of a plurality of antennas of the transmitter and the IRS; the transmitter determining an antenna selection metric based on the channel gain when transmitting the pilot signal to the receiver via the antenna set of the plurality of antennas of the transmitter and the IRS; the transmitter identifying, from the plurality of antennas, the antenna set that provides the maximum antenna selection metric; the transmitter determining a reflection coefficient of each reflector of the IRS based on the antenna set; the transmitter configuring the reflectors of the IRS with the reflection coefficients; the transmitter determining, based on the reflection coefficients and the antenna set, an optimal beamforming required to transmit a signal from the antenna set; and the transmitter, based on the optimal beamforming, transmitting the signal via the configured reflectors. The antenna set transmits a signal to the receiver; the receiver estimates the channel gain by receiving the pilot signal from the antenna set of the plurality of antennas of the transmitter of the wireless communication system and the IRS; the receiver determines the antenna selection metric based on the channel gain when receiving the pilot signal from the antenna set of the plurality of antennas of the transmitter and the IRS; the receiver identifies from the plurality of antennas the antenna set that provides the maximum antenna selection metric; the receiver determines the reflection coefficient of each reflector of the IRS based on the identified antenna set; and the receiver reports the identified antenna set and the reflection coefficient of each reflector to the transmitter so as to configure the reflectors of the IRS with the reflection coefficients and enable the transmitter to transmit signals via the identified antenna set.

[0020] According to another aspect of this disclosure, a method is provided for enhancing the power of a signal received at a receiver in a wireless communication system using an IRS. The method includes: a transmitter of the wireless communication system estimating a first channel gain by transmitting a pilot signal to the receiver via each of a plurality of antennas of the transmitter and the IRS, wherein the reflection coefficient of each reflector of the IRS is set to zero; the transmitter estimating a second channel gain by transmitting the pilot signal to the receiver via each of the plurality of antennas and the IRS, wherein the reflection coefficient of each reflector of the IRS is set to one; the transmitter determining, for each antenna, the difference between the second channel gain and the first channel gain; and the transmitter determining, for each antenna, the difference between the second channel gain and the first channel gain. The transmitter sorts each antenna in descending order of the difference between the channel gain and the first channel gain; the transmitter selects the first n antennas from the sorted antennas as an antenna set; the transmitter transmits the pilot signal via the selected antenna set; the transmitter determines the reflection coefficient of each reflector of the IRS based on the antenna set; the transmitter configures the reflectors of the IRS with the reflection coefficients; the transmitter determines the optimal beamforming required to transmit signals from the antenna set based on the reflection coefficients and the antenna set; and the transmitter transmits signals to the receiver via the configured reflectors and the antenna set based on the optimal beamforming.

[0021] According to another aspect of this disclosure, a method is provided for enhancing the power of a signal received at a receiver in a wireless communication system using an IRS. The method includes: the receiver estimating a first channel gain by receiving pilot signals from each of a plurality of antennas of a transmitter of the wireless communication system and the IRS, wherein the reflection coefficient of each reflector of the IRS is set to zero; the receiver estimating a second channel gain by receiving the pilot signals from each of the plurality of antennas and the IRS, wherein the reflection coefficient of each reflector of the IRS is set to one; the receiver determining the difference between the second channel gain and the first channel gain for each antenna; the receiver sorting each antenna in descending order of the difference between the second channel gain and the first channel gain; the receiver selecting the first n antennas from the sorted antennas as an antenna set; the receiver determining the reflection coefficient of each reflector of the IRS based on the antenna set and the pilot signals transmitted by the transmitter; and the receiver reporting the selected first n antennas and the reflection coefficient of each reflector to the transmitter to configure the reflectors of the IRS with the reflection coefficients and enable the transmitter to transmit signals via the identified antennas.

[0022] According to another aspect of this disclosure, a transmitter is provided for enhancing the power of a signal received at a receiver in a wireless communication system using an IRS. The transmitter includes: a memory; a communicator equipped with a plurality of antennas and a plurality of radio frequency (RF) chains; and processing circuitry connected to the memory and the communicator. The processing circuitry is configured to: estimate a channel gain by transmitting a pilot signal to the receiver via each of the plurality of antennas of the transmitter and the IRS; determine an antenna selection metric based on the channel gain when transmitting the pilot signal to the receiver via each of the plurality of antennas of the transmitter and the IRS; identify from the plurality of antennas an antenna that provides the maximum antenna selection metric; determine the reflection coefficient of each reflector of the IRS based on the identified antenna; configure the reflectors of the IRS with the reflection coefficients; and transmit a signal to the receiver via the identified antenna and the configured reflector.

[0023] According to another aspect of this disclosure, a receiver is provided for enhancing the power of signals received from a transmitter and an IRS. The receiver includes: a memory; a communicator equipped with at least one receiving antenna and at least one receiving radio frequency (RF) chain; and processing circuitry connected to the memory and the communicator. The processing circuitry is configured to: estimate a channel gain by receiving pilot signals from each of a plurality of antennas of the transmitter and the IRS; determine an antenna selection metric based on the channel gain when receiving the pilot signals from each of the plurality of antennas of the transmitter and the IRS; identify from the plurality of antennas an antenna that provides the maximum antenna selection metric; determine the reflection coefficient of each reflector of the IRS based on the identified antenna; and report the identified antenna and the reflection coefficient of each reflector to the transmitter so as to configure the reflectors of the IRS with the reflection coefficients and enable the transmitter to transmit signals via the identified antenna.

[0024] According to another aspect of this disclosure, a transmitter is provided for enhancing the power of a signal received at a receiver in a wireless communication system using an IRS. The transmitter includes: a memory; a communicator equipped with a plurality of antennas and a plurality of radio frequency (RF) chains; and processing circuitry connected to the memory and the communicator. The processing circuit is configured to: estimate a first channel gain by transmitting pilot signals to the receiver via each of the plurality of antennas of the transmitter and the IRS, wherein the reflection coefficient of each reflector of the IRS is set to zero; estimate a second channel gain by transmitting the pilot signals to the receiver via each of the plurality of antennas and the IRS, wherein the reflection coefficient of each reflector of the IRS is set to one; determine the difference between the second channel gain and the first channel gain for each antenna; identify the antenna among the plurality of antennas whose sum of the magnitude of the first channel gain and the magnitude of the difference between the second channel gain and the first channel gain is the largest; determine the reflection coefficient of each reflector of the IRS by transmitting each pilot signal in the set of pilot signals via the identified antenna and the IRS, wherein the number of pilot signals in the set of pilot signals is equal to the number of reflectors in the IRS; and transmit a signal to the receiver via the identified antenna and the IRS based on the reflection coefficient.

[0025] According to another aspect of this disclosure, a receiver is provided for enhancing the power of signals received from a transmitter and an IRS. The receiver includes: a memory; a communicator equipped with at least one receiving antenna and at least one receiving radio frequency (RF) chain; and processing circuitry connected to the memory and the communicator. The processing circuit is configured to: estimate a first channel gain by receiving pilot signals from each of a plurality of antennas of the transmitter and the IRS, wherein the reflection coefficient of each reflector of the IRS is set to zero; estimate a second channel gain by receiving the pilot signals from each of the plurality of antennas and the IRS, wherein the reflection coefficient of each reflector of the IRS is set to one; determine the difference between the second channel gain and the first channel gain for each antenna; identify the antenna among the plurality of antennas whose sum of the magnitude of the first channel gain and the magnitude of the difference between the second channel gain and the first channel gain is the largest; determine the reflection coefficient of each reflector of the IRS by receiving each pilot signal from the set of pilot signals of the identified antennas and the IRS, wherein the number of pilot signals in the set of pilot signals is equal to the number of reflectors in the IRS; and report the identified antennas and the reflection coefficients of each reflector to the transmitter so as to configure the reflectors of the IRS with the reflection coefficients and enable the transmitter to transmit signals via the identified antennas.

[0026] According to another aspect of this disclosure, a transmitter is provided for enhancing the power of a signal received at a receiver in a wireless communication system using an IRS. The transmitter includes: a memory; a communicator equipped with a plurality of antennas and a plurality of radio frequency (RF) chains; and processing circuitry connected to the memory and the communicator. The processing circuitry is configured to: estimate a channel gain by transmitting a pilot signal to the receiver via an antenna set of the plurality of antennas of the transmitter and the IRS; determine an antenna selection metric based on the channel gain when transmitting the pilot signal to the receiver via the antenna set of the plurality of antennas of the transmitter and the IRS; identify an antenna set from the plurality of antennas that provides the maximum antenna selection metric; determine the reflection coefficient of each reflector of the IRS based on the antenna set; configure the reflectors of the IRS with the reflection coefficients; determine the optimal beamforming required for transmitting a signal from the antenna set based on the reflection coefficients and the antenna set; and transmit a signal to the receiver via the configured reflectors and the antenna set based on the optimal beamforming.

[0027] According to another aspect of this disclosure, a receiver is provided for enhancing the power of signals received from a transmitter and an IRS. The receiver includes: a memory; a communicator equipped with at least one receiving antenna and at least one receiving radio frequency (RF) chain; and processing circuitry connected to the memory and the communicator. The processing circuitry is configured to: estimate a channel gain by receiving pilot signals from an antenna set from a plurality of antennas of the transmitter and the IRS; determine an antenna selection metric based on the channel gain received from the pilot signals from the antenna set from the plurality of antennas of the transmitter and the IRS; identify an antenna set from the plurality of antennas that provides the maximum antenna selection metric; determine the reflection coefficient of each reflector of the IRS based on the identified antenna set; and report the identified antenna set and the reflection coefficient of each reflector to the transmitter so as to configure the reflectors of the IRS with the reflection coefficients and enable the transmitter to transmit signals via the identified antenna set.

[0028] According to another aspect of this disclosure, a transmitter is provided for enhancing the power of a signal received at a receiver in a wireless communication system using an IRS. The transmitter includes: a memory; a communicator equipped with a plurality of antennas and a plurality of radio frequency (RF) chains; and processing circuitry connected to the memory and the communicator. The processing circuitry is configured to: estimate a first channel gain by transmitting pilot signals to the receiver via each of the plurality of antennas of the transmitter and the IRS, wherein the reflection coefficient of each reflector of the IRS is set to zero; estimate a second channel gain by transmitting the pilot signals to the receiver via each of the plurality of antennas and the IRS, wherein the reflection coefficient of each reflector of the IRS is set to one; determine the difference between the second channel gain and the first channel gain for each antenna; sort each antenna in descending order of the difference between the second channel gain and the first channel gain; select the first n antennas from the sorted antennas as an antenna set; transmit the pilot signals via the selected antenna set; determine the reflection coefficient of each reflector of the IRS based on the antenna set; configure the reflectors of the IRS with the reflection coefficients; determine the optimal beamforming required for transmitting signals from the antenna set based on the reflection coefficients and the antenna set; and transmit signals to the receiver via the configured reflectors and the antenna set based on the optimal beamforming.

[0029] According to another aspect of this disclosure, a receiver is provided for enhancing the power of signals received from a transmitter and an IRS. The receiver includes: a memory; a communicator equipped with at least one receiving antenna and at least one receiving radio frequency (RF) chain; and processing circuitry connected to the memory and the communicator. The processing circuit is configured to: estimate a first channel gain by receiving pilot signals from each of the plurality of antennas of the transmitter and the IRS, wherein the reflection coefficient of each reflector of the IRS is set to zero; estimate a second channel gain by receiving the pilot signals from each of the plurality of antennas and the IRS, wherein the reflection coefficient of each reflector of the IRS is set to one; determine the difference between the second channel gain and the first channel gain for each antenna; sort each antenna in descending order of the difference between the second channel gain and the first channel gain; select the first n antennas from the sorted antennas as an antenna set; determine the reflection coefficient of each reflector of the IRS based on the antenna set and the pilot signals transmitted by the transmitter; and report the selected first n antennas and the reflection coefficient of each reflector to the transmitter so as to configure the reflectors of the IRS with the reflection coefficients and enable the transmitter to transmit signals via the identified antennas.

[0030] Other aspects, advantages, and salient features of this disclosure will become apparent to those skilled in the art from the following detailed description, which discloses various embodiments of the disclosure in conjunction with the accompanying drawings. Attached Figure Description

[0031] The above and other aspects, features, and advantages of certain embodiments of the present disclosure will become clearer from the following description taken in conjunction with the accompanying drawings, in which:

[0032] Figure 1 This is a block diagram of a wireless communication system according to embodiments of the present disclosure for enhancing the power of a signal received at a receiver using a smart reflective surface (IRS).

[0033] Figure 2A This is a flowchart illustrating a method for enhancing the power of a signal received at a receiver using an IRS, according to an embodiment of the present disclosure.

[0034] Figure 2B This is a flowchart illustrating a method for enhancing the power of a signal received at a receiver using an IRS, according to an embodiment of the present disclosure.

[0035] Figure 2C This is a flowchart illustrating a method for enhancing the power of a signal received at a receiver using an IRS, according to an embodiment of the present disclosure.

[0036] Figure 2D This is a flowchart illustrating a method for enhancing the power of a signal received at a receiver using an IRS, according to an embodiment of the present disclosure.

[0037] Figure 3A This is a flowchart illustrating a method for enhancing the power of a signal received at a receiver using an IRS, according to an embodiment of the present disclosure.

[0038] Figure 3B This is a flowchart illustrating a method for enhancing the power of a signal received at a receiver using an IRS, according to an embodiment of the present disclosure.

[0039] Figure 3C This is a flowchart illustrating a method for enhancing the power of a signal received at a receiver using an IRS, according to an embodiment of the present disclosure.

[0040] Figure 3D This is a flowchart illustrating a method for enhancing the power of a signal received at a receiver using an IRS, according to an embodiment of the present disclosure.

[0041] Figure 4 This is a schematic diagram illustrating a single antenna selection and passive beamforming for delivering a signal to a receiver according to an embodiment of the present disclosure.

[0042] Figure 5A and Figure 5B This is a schematic diagram illustrating a method for estimating direct link channel gain and reflected link channel gain according to an embodiment of the present disclosure.

[0043] Figure 6 It is a graphical representation of the average symbol error probability (SEP) as a function of peak transmit power for different numbers of IRS reflectors according to embodiments of the present disclosure.

[0044] Figure 7 It is a graphical representation of the signal-to-noise ratio (SNR) at the receiver as a function of the distance of the receiver from the transmitter for different numbers of IRS reflectors according to embodiments of the present disclosure.

[0045] Figure 8 It is a graphical representation of the average SEP as a function of peak transmit power for different numbers of antennas at the transmitter, according to embodiments of the present disclosure.

[0046] Throughout the accompanying drawings, it should be noted that similar reference numerals are used to depict the same or similar elements, features, and structures. Detailed Implementation

[0047] The following description, provided with reference to the accompanying drawings, is intended to aid in a full understanding of the various embodiments of this disclosure as defined by the claims and their equivalents. It includes various specific details to aid this understanding, but these details should be considered exemplary only. Therefore, those skilled in the art will recognize that various changes and modifications can be made to the various embodiments described herein without departing from the scope and spirit of this disclosure. Additionally, descriptions of well-known functions and constructions may be omitted for clarity and brevity.

[0048] The terms and words used in the following description and claims are not limited to their literal meaning, but are merely used by the inventors to achieve a clear and consistent understanding of this disclosure. Therefore, it will be clear to those skilled in the art that the following description of various embodiments of this disclosure is provided for illustrative purposes only and not to limit the disclosure as defined by the appended claims and their equivalents.

[0049] It should be understood that, unless the context clearly specifies otherwise, the singular forms “a,” “an,” and “the” include plural references. Thus, for example, a reference to “component surface” includes a reference to one or more such surfaces.

[0050] As is conventional in the art, embodiments can be described and illustrated by blocks that perform one or more described functions. These blocks, which may be referred to herein as managers, units, modules, hardware components, etc., are physically implemented by analog and / or digital circuitry such as logic gates, integrated circuits, microprocessors, microcontrollers, memory circuits, passive electronic components, active electronic components, optical components, hardwired circuits, etc., and may optionally be driven by firmware. For example, the circuitry may be embodied in one or more semiconductor chips, or on a substrate support such as a printed circuit board. The circuitry constituting a block may be implemented by dedicated hardware, or by a processor (e.g., one or more programmed microprocessors and associated circuitry), or by a combination of dedicated hardware for performing some functions of the block and a processor for performing other functions of the block. Without departing from the scope of this disclosure, each block of an embodiment may be physically divided into two or more interactive and discrete blocks. Similarly, without departing from the scope of this disclosure, the blocks of an embodiment may be physically combined into more complex blocks.

[0051] The accompanying drawings are provided to aid in the easy understanding of the various technical features, and it should be understood that the embodiments presented herein are not limited to the drawings. Therefore, this disclosure should be construed as extending to any variations, equivalents, and substitutions other than those specifically stated in the drawings. Although the terms first, second, etc., may be used herein to describe various elements, these elements should not be limited by these terms. These terms are generally used only to distinguish one element from another.

[0052] Notation: Scalars are represented by lowercase letters. Vectors and matrices are represented by bold lowercase letters and uppercase letters, respectively. C mxn Let m represent the set of all complex-valued matrices of size m×n and |a|, arg(a) and a * Let ||x|| represent the absolute value, phase, and conjugate of the complex number a, respectively. and [x] n Let x represent the 2-norm, conjugate transpose, and nth element of vector x.

[0053] Therefore, embodiments of this document provide a method for enhancing the power of a signal received at a receiver in a wireless communication system using an IRS. The method includes: a transmitter of the wireless communication system estimating a channel gain by transmitting a pilot signal to the receiver via each of a plurality of antennas of the transmitter and the IRS. The method includes: the transmitter determining an antenna selection metric based on the channel gain when transmitting the pilot signal to the receiver via each of the plurality of antennas of the transmitter and the IRS. The method includes: the transmitter identifying from the plurality of antennas an antenna that provides the maximum antenna selection metric. The method includes: the transmitter determining a reflection coefficient of each reflector of the IRS based on the identified antenna. The method includes: the transmitter configuring the reflectors of the IRS with the reflection coefficients. The method includes: the transmitter transmitting a signal to the receiver via the identified antenna and the configured reflector.

[0054] Therefore, embodiments of this document provide a method for enhancing the power of a signal received at a receiver in a wireless communication system using an IRS. The method includes: the receiver estimating a channel gain by receiving pilot signals from each of a plurality of antennas of a transmitter of the wireless communication system and the IRS. The method includes: the receiver determining an antenna selection metric based on the channel gain when receiving the pilot signals from each of the plurality of antennas of the transmitter and the IRS. The method includes: the receiver identifying from the plurality of antennas an antenna that provides the maximum antenna selection metric. The method includes: the receiver determining the reflection coefficient of each reflector of the IRS based on the identified antenna. The method includes: the receiver reporting the identified antenna and the reflection coefficient of each reflector to the transmitter to configure the reflectors of the IRS with the reflection coefficients and enable the transmitter to transmit signals via the identified antenna.

[0055] Therefore, embodiments of this document provide a method for enhancing the power of a signal received at a receiver in a wireless communication system using an IRS. The method includes: a transmitter of the wireless communication system estimating a first channel gain by transmitting pilot signals to the receiver via each of a plurality of antennas of the transmitter and the IRS, wherein the reflection coefficient of each reflector of the IRS is set to zero. The method includes: the transmitter estimating a second channel gain by transmitting the pilot signals to the receiver via each of the plurality of antennas and the IRS, wherein the reflection coefficient of each reflector of the IRS is set to one. The method includes: the transmitter determining the difference between the second channel gain and the first channel gain for each antenna. The method includes: the transmitter identifying the antenna among the plurality of antennas whose sum of the magnitude of the first channel gain and the magnitude of the difference between the second channel gain and the first channel gain is the largest. The method includes: the transmitter determining the reflection coefficient of each reflector of the IRS by transmitting each pilot signal from a set of pilot signals via the identified antenna and the IRS, wherein the number of pilot signals in the set of pilot signals is equal to the number of reflectors in the IRS. The method includes: the transmitter transmitting a signal to the receiver via an identified antenna and the IRS based on the reflection coefficient.

[0056] Therefore, embodiments of this document provide a method for enhancing the power of a signal received at a receiver in a wireless communication system using an IRS. The method includes: the receiver estimating a first channel gain by receiving pilot signals from each of a plurality of antennas of a transmitter of the wireless communication system and the IRS, wherein the reflection coefficient of each reflector of the IRS is set to zero. The method includes: the receiver estimating a second channel gain by receiving the pilot signals from each of the plurality of antennas and the IRS, wherein the reflection coefficient of each reflector of the IRS is set to one. The method includes: the receiver determining the difference between the second channel gain and the first channel gain for each antenna. The method includes: the transmitter identifying the antenna among the plurality of antennas whose sum of the magnitude of the first channel gain and the magnitude of the difference between the second channel gain and the first channel gain is the largest. The method includes: the receiver determining the reflection coefficient of each reflector of the IRS by receiving each pilot signal from a set of pilot signals from the identified antennas and the IRS, wherein the number of pilot signals in the set of pilot signals is equal to the number of reflectors in the IRS. The method includes: the receiver reporting the identified antennas and the reflection coefficients of each reflector to the transmitter, so as to configure the reflectors of the IRS with the reflection coefficients and enable the transmitter to transmit signals via the identified antennas.

[0057] Therefore, embodiments of this document provide a method for enhancing the power of a signal received at a receiver in a wireless communication system using an IRS. The method includes: a transmitter of the wireless communication system estimating a channel gain by transmitting a pilot signal to the receiver via an antenna set of a plurality of antennas of the transmitter and the IRS. The method includes: the transmitter determining an antenna selection metric based on the channel gain when transmitting the pilot signal to the receiver via the antenna set of the plurality of antennas of the transmitter and the IRS. The method includes: the transmitter identifying, from the plurality of antennas, the antenna set that provides the maximum antenna selection metric. The method includes: the transmitter determining the reflection coefficient of each reflector of the IRS based on the antenna set. The method includes: the transmitter configuring the reflectors of the IRS with the reflection coefficients. The method includes: the transmitter determining, based on the reflection coefficients and the antenna set, the optimal beamforming required for transmitting a signal from the antenna set. The method includes: the transmitter transmitting a signal to the receiver via the configured reflectors and the antenna set based on the optimal beamforming. The method includes: the receiver estimating the channel gain by receiving the antenna set from the plurality of antennas of the transmitter of the wireless communication system and the pilot signal of the IRS. The method includes: the receiver determining the antenna selection metric based on the channel gain when receiving the antenna set from the plurality of antennas of the transmitter and the pilot signal of the IRS. The method includes: the receiver identifying from the plurality of antennas an antenna set that provides the maximum antenna selection metric. The method includes: the receiver determining the reflection coefficient of each reflector of the IRS based on the identified antenna set. The method includes: the receiver reporting the identified antenna set and the reflection coefficient of each reflector to the transmitter to configure the reflectors of the IRS with the reflection coefficients and enable the transmitter to transmit signals via the identified antenna set.

[0058] Therefore, embodiments of this document provide a method for enhancing the power of a signal received at a receiver in a wireless communication system using an IRS. The method includes: a transmitter of the wireless communication system estimating a first channel gain by transmitting a pilot signal to the receiver via each of a plurality of antennas of the transmitter and the IRS, wherein the reflection coefficient of each reflector of the IRS is set to zero. The method includes: the transmitter estimating a second channel gain by transmitting the pilot signal to the receiver via each of the plurality of antennas and the IRS, wherein the reflection coefficient of each reflector of the IRS is set to one. The method includes: the transmitter determining the difference between the second channel gain and the first channel gain for each antenna. The method includes: the transmitter sorting each antenna in descending order of the difference between the second channel gain and the first channel gain. The method includes: the transmitter selecting the first n antennas from the sorted antennas as an antenna set. The method includes: the transmitter transmitting the pilot signal via the selected antenna set. The method includes: the transmitter determining the reflection coefficient of each reflector of the IRS based on the antenna set. The method includes: the transmitter configuring the reflector of the IRS with the reflection coefficient. The method includes: the transmitter determining optimal beamforming required for transmitting a signal from the antenna set based on the reflection coefficient and the antenna set. The method includes: the transmitter transmitting a signal to the receiver via the configured reflector and the antenna set based on the optimal beamforming.

[0059] Therefore, embodiments of this document provide a method for enhancing the power of a signal received at a receiver in a wireless communication system using an IRS. The method includes: the receiver estimating a first channel gain by receiving pilot signals from each of a plurality of antennas of a transmitter of the wireless communication system and the IRS, wherein the reflection coefficient of each reflector of the IRS is set to zero. The method includes: the receiver estimating a second channel gain by receiving the pilot signals from each of the plurality of antennas and the IRS, wherein the reflection coefficient of each reflector of the IRS is set to one. The method includes: the receiver determining the difference between the second channel gain and the first channel gain for each antenna. The method includes: the receiver sorting each antenna in descending order of the difference between the second channel gain and the first channel gain. The method includes: the receiver selecting the first n antennas from the sorted antennas as an antenna set. The method includes: the receiver determining the reflection coefficient of each reflector of the IRS based on the antenna set and the pilot signals transmitted by the transmitter. The method includes: the receiver reporting to the transmitter the reflection coefficients of the first n selected antennas and each reflector, so as to configure the reflectors of the IRS with the reflection coefficients and enable the transmitter to transmit signals via the identified antennas.

[0060] Therefore, embodiments of this document provide a transmitter for enhancing the power of a signal received at a receiver in a wireless communication system using an IRS. The transmitter includes: a memory; a communicator equipped with a plurality of antennas and a plurality of radio frequency (RF) chains; and processing circuitry connected to the memory and the communicator. The processing circuitry is configured to: estimate a channel gain by transmitting a pilot signal to the receiver via each of the plurality of antennas of the transmitter and the IRS. The processing circuitry is configured to: determine an antenna selection metric based on the channel gain when transmitting the pilot signal to the receiver via each of the plurality of antennas of the transmitter and the IRS. The processing circuitry is configured to: identify from the plurality of antennas an antenna that provides the maximum antenna selection metric. The processing circuitry is configured to: determine the reflection coefficient of each reflector of the IRS based on the identified antenna. The processing circuitry is configured to: configure the reflectors of the IRS with the reflection coefficients. The processing circuitry is configured to: transmit a signal to the receiver via the identified antenna and the configured reflector.

[0061] Therefore, embodiments of this document provide a receiver for enhancing the power of signals received from a transmitter and an IRS. The receiver includes: a memory; a communicator equipped with at least one receiving antenna and at least one receiving radio frequency (RF) chain; and processing circuitry connected to the memory and the communicator. The processing circuitry is configured to: estimate a channel gain by receiving pilot signals from each of a plurality of antennas of the transmitter and the IRS. The processing circuitry is configured to: determine an antenna selection metric based on the channel gain when receiving the pilot signals from each of the plurality of antennas of the transmitter and the IRS. The processing circuitry is configured to: identify from the plurality of antennas an antenna that provides the maximum antenna selection metric. The processing circuitry is configured to: determine the reflection coefficient of each reflector of the IRS based on the identified antenna. The processing circuitry is configured to: report the identified antenna and the reflection coefficient of each reflector to the transmitter so as to configure the reflectors of the IRS with the reflection coefficients and enable the transmitter to transmit signals via the identified antenna.

[0062] Therefore, embodiments of this document provide a transmitter for enhancing the power of a signal received at a receiver in a wireless communication system using an IRS. The transmitter includes: a memory; a communicator equipped with a plurality of antennas and a plurality of radio frequency (RF) chains; and processing circuitry connected to the memory and the communicator. The processing circuitry is configured to: estimate a first channel gain by transmitting pilot signals to the receiver via each of the plurality of antennas of the transmitter and the IRS, wherein the reflection coefficient of each reflector of the IRS is set to zero. The processing circuitry is configured to: estimate a second channel gain by transmitting the pilot signals to the receiver via each of the plurality of antennas and the IRS, wherein the reflection coefficient of each reflector of the IRS is set to one. The processing circuitry is configured to: determine the difference between the second channel gain and the first channel gain for each antenna. The processing circuitry is configured to: identify the antenna among the plurality of antennas whose sum of the magnitude of the first channel gain and the magnitude of the difference between the second channel gain and the first channel gain is the largest. The processing circuitry is configured to: determine the reflection coefficient of each reflector of the IRS by transmitting each pilot signal from a set of pilot signals via an identified antenna and the IRS, wherein the number of pilot signals in the set of pilot signals is equal to the number of reflectors in the IRS. The processing circuitry is configured to: transmit a signal to the receiver via the identified antenna and the IRS based on the reflection coefficient.

[0063] Therefore, embodiments of this document provide a receiver for enhancing the power of signals received from a transmitter and an IRS. The receiver includes: a memory; a communicator equipped with at least one receiving antenna and at least one receiving radio frequency (RF) chain; and processing circuitry connected to the memory and the communicator. The processing circuitry is configured to: estimate a first channel gain by receiving pilot signals from each of a plurality of antennas of the transmitter and the IRS, wherein the reflection coefficient of each reflector of the IRS is set to zero. The processing circuitry is configured to: estimate a second channel gain by receiving the pilot signals from each of the plurality of antennas and the IRS, wherein the reflection coefficient of each reflector of the IRS is set to one. The processing circuitry is configured to: determine the difference between the second channel gain and the first channel gain for each antenna. The processing circuitry is configured to: identify the antenna among the plurality of antennas whose sum of the magnitude of the first channel gain and the magnitude of the difference between the second channel gain and the first channel gain is the largest. The processing circuitry is configured to: determine the reflection coefficient of each reflector of the IRS by receiving each pilot signal from the identified antenna and the pilot signal set of the IRS, wherein the number of pilot signals in the pilot signal set is equal to the number of reflectors in the IRS. The processing circuitry is also configured to: report the identified antenna and the reflection coefficient of each reflector to the transmitter, so as to configure the reflectors of the IRS with the reflection coefficients and enable the transmitter to transmit signals via the identified antenna.

[0064] Therefore, embodiments of this document provide a transmitter for enhancing the power of a signal received at a receiver in a wireless communication system using an IRS. The transmitter includes: a memory; a communicator equipped with a plurality of antennas and a plurality of radio frequency (RF) chains; and processing circuitry connected to the memory and the communicator. The processing circuitry is configured to: estimate a channel gain by transmitting a pilot signal to the receiver via an antenna set of the plurality of antennas of the transmitter and the IRS. The processing circuitry is configured to: determine an antenna selection metric based on the channel gain when transmitting the pilot signal to the receiver via the antenna set of the plurality of antennas of the transmitter and the IRS. The processing circuitry is configured to: identify from the plurality of antennas an antenna set that provides the maximum antenna selection metric. The processing circuitry is configured to: determine the reflection coefficient of each reflector of the IRS based on the antenna set. The processing circuitry is configured to: configure the reflectors of the IRS with the reflection coefficients. The processing circuitry is configured to: determine the optimal beamforming required for transmitting a signal from the antenna set based on the reflection coefficients and the antenna set. The processing circuitry is configured to transmit a signal to the receiver via the configured reflector and the antenna set based on the optimal beamforming.

[0065] Therefore, embodiments of this document provide a receiver for enhancing the power of signals received from a transmitter and an IRS. The receiver includes: a memory; a communicator equipped with at least one receiving antenna and at least one receiving radio frequency (RF) chain; and processing circuitry connected to the memory and the communicator. The processing circuitry is configured to: estimate a channel gain by receiving a set of antennas from a plurality of antennas of the transmitter and pilot signals from the IRS. The processing circuitry is configured to: determine an antenna selection metric based on the channel gain when receiving the set of antennas from the plurality of antennas of the transmitter and the pilot signals from the IRS. The processing circuitry is configured to: identify an antenna set from the plurality of antennas that provides the maximum antenna selection metric. The processing circuitry is configured to: determine the reflection coefficient of each reflector of the IRS based on the identified antenna set. The processing circuitry is configured to: report the identified antenna set and the reflection coefficient of each reflector to the transmitter so as to configure the reflectors of the IRS with the reflection coefficients and enable the transmitter to transmit signals via the identified antenna set.

[0066] Therefore, embodiments of this document provide a transmitter for enhancing the power of a signal received at a receiver in a wireless communication system using an IRS. The transmitter includes: a memory; a communicator equipped with a plurality of antennas and a plurality of radio frequency (RF) chains; and processing circuitry connected to the memory and the communicator. The processing circuitry is configured to: estimate a first channel gain by transmitting pilot signals to the receiver via each of the plurality of antennas of the transmitter and the IRS, wherein the reflection coefficient of each reflector of the IRS is set to zero. The processing circuitry is configured to: estimate a second channel gain by transmitting the pilot signals to the receiver via each of the plurality of antennas and the IRS, wherein the reflection coefficient of each reflector of the IRS is set to one. The processing circuitry is configured to: determine the difference between the second channel gain and the first channel gain for each antenna. The processing circuitry is configured to: sort each antenna in descending order of the difference between the second channel gain and the first channel gain. The processing circuitry is configured to: select the first n antennas from the sorted antennas as an antenna set. The processing circuitry is configured to: transmit the pilot signal via a selected set of antennas. The processing circuitry is configured to: determine the reflection coefficient of each reflector of the IRS based on the antenna set. The processing circuitry is configured to: configure the reflectors of the IRS using the reflection coefficients. The processing circuitry is configured to: determine the optimal beamforming required for transmitting a signal from the antenna set based on the reflection coefficients and the antenna set. The processing circuitry is configured to: transmit a signal to the receiver via the configured reflectors and the antenna set based on the optimal beamforming.

[0067] Therefore, embodiments of this document provide a receiver for enhancing the power of signals received from a transmitter and an IRS. The receiver includes: a memory; a communicator equipped with at least one receiving antenna and at least one receiving radio frequency (RF) chain; and processing circuitry connected to the memory and the communicator. The processing circuitry is configured to: estimate a first channel gain by receiving pilot signals from each of a plurality of antennas of the transmitter and the IRS, wherein the reflection coefficient of each reflector of the IRS is set to zero. The processing circuitry is configured to: estimate a second channel gain by receiving the pilot signals from each of the plurality of antennas and the IRS, wherein the reflection coefficient of each reflector of the IRS is set to one. The processing circuitry is configured to: determine the difference between the second channel gain and the first channel gain for each antenna. The processing circuitry is configured to: sort each antenna in descending order of the difference between the second channel gain and the first channel gain. The processing circuitry is configured to: select the first n antennas from the sorted antennas as an antenna set. The processing circuitry is configured to: determine the reflection coefficient of each reflector of the IRS based on the antenna set and the pilot signal transmitted by the transmitter. The processing circuitry is also configured to: report the selected first n antennas and the reflection coefficient of each reflector to the transmitter, so as to configure the reflectors of the IRS with the reflection coefficients and enable the transmitter to transmit signals via the identified antennas.

[0068] Existing systems select the antenna or antenna set for signal transmission by assuming that Channel State Information (CSI) is available at both the transmitter and the IRS. Since the IRS is a passive element, the CSI at the IRS is practically impossible to calculate. Unlike existing methods and systems, the proposed transmitter / receiver selects the antenna or antenna set for signal transmission by assuming that CSI is available only at the transmitter. Therefore, since the CSI at the IRS is not considered in antenna selection, the antenna selection will be accurate.

[0069] Unlike existing methods and systems, the proposed method uses a smaller number of pilot signals to determine the channel gain for antenna selection. Therefore, the computation required for antenna selection is significantly less than that required by existing methods and systems.

[0070] The proposed method selects a subset of antennas to be used for transmission using RF chains, which is determined to maximize the power of the signal received at the receiver. This antenna selection method helps the transmitter achieve performance gains comparable to those achieved by existing transmitters using the same number of RF chains and antennas, resulting in significant cost savings. Unlike existing transmitters, the proposed transmitter contains fewer RF chains than antennas, which significantly reduces the transmitter's design complexity, size, and manufacturing cost.

[0071] Now refer to the accompanying drawings, and more specifically to... Figure 1 , Figure 2A , Figure 2B , Figure 2C , Figure 2D , Figure 3A , Figure 3B , Figure 3C , Figure 3B , Figure 4 , Figure 5A , Figure 5B , Figure 6 , Figure 7 and Figure 8 A preferred embodiment is shown.

[0072] Figure 1 This is a block diagram of a wireless communication system according to embodiments of the present disclosure for using an IRS to enhance the power of a signal received at a receiver.

[0073] Reference Figure 1 The wireless communication system (1000) includes a transmitter (100), an IRS (200), and a receiver (300). In embodiments of this disclosure, the transmitter (100) includes an antenna and a reflection coefficient controller (ARCC) (110), a memory (120), a processor (130), and a communicator (140). In embodiments of this disclosure, the communicator (140) is equipped with N t One antenna and N RF There are N RF chains (1141a-1141n), where N RF ≤N t And “RF” and “t” are natural numbers. In embodiments of this disclosure, the receiver (300) includes an ARCC (310), a memory (320), a processor (330), and a communicator (340). In embodiments of this disclosure, the communicator (340) is equipped with a single antenna and an RF chain (341). The transmitter (100) communicates with the receiver (300) via a direct link (h) between the transmitter's (100) antenna and the receiver's (300) antenna. d And through the reflection link (G+h) formed between the antenna of the transmitter (100) and the antenna of the receiver (300) due to the IRS (200). rThe IRS (200) communicates with the receiver (300). The IRS (200) is equipped with N passive reflectors (also called IRS reflectors) and an IRS controller (210), where N is a natural number. The IRS controller (210) tunes each IRS reflector based on inputs received from the transmitter (100) and / or the receiver (300). Therefore, any change in IRS properties will also affect the channel. The IRS controller (210) is configured with reflection coefficients from the transmitter (100) to control the magnitude and phase shift (θ) of the reflection loss (β) of the IRS reflector. The transmitter (100) receives signals from the antenna set {1,2,...,N}. t Dynamically select N in} RF The antennas are connected to the available RF chains (1141a-1141n) and transmit beamforming is performed.

[0074] In embodiments of this disclosure, if the base station (BS) operates as a transmitter (100), the user equipment (UE) operates as a receiver (300), and if the UE operates as a transmitter (100), the BS operates as a receiver (300). Examples of BS are, but are not limited to, eNodeB, gNodeB, etc. Examples of UE are, but are not limited to, smartphones, wearable devices, Internet of Things (IoT) devices, laptops, etc.

[0075] Memory (120) stores instructions to be executed by processor (130). Memory (320) stores instructions to be executed by processor (330). Memory (120, 320) may include non-volatile storage elements. Examples of such non-volatile storage elements may include magnetic hard disks, optical disks, floppy disks, flash memory, or electrically programmable memory (EPROM) or electrically erasable programmable memory (EEPROM). Additionally, in some examples, memory (120, 320) may be considered a non-transitory storage medium. The term "non-transitory" may indicate that the storage medium is not embodied in a carrier wave or propagating signal. However, the term "non-transitory" should not be interpreted as memory (120, 320) being immovable. In some examples, memory (120, 320) can be configured to store a larger amount of information than its storage space allows. In some examples, non-transitory storage media may store data that can change over time (e.g., in random access memory (RAM) or cache). The memory (120, 320) can be an internal storage unit, or it can be an external storage unit of the transmitter (100), a cloud storage device, or any other type of external storage device. The memory (320) can be an internal storage unit, or it can be an external storage unit of the receiver (300), a cloud storage device, or any other type of external storage device.

[0076] Processor (130) is configured to execute instructions stored in memory (120). Processor (330) is configured to execute instructions stored in memory (320). Processors (130, 330) may be general-purpose processors (such as central processing units (CPUs), application processors (APs), etc.), graphics-only units (such as graphics processing units (GPUs)), visual processing units (VPUs), etc. Processors (130, 330) may include multiple cores to execute instructions. Communicator (140) is configured for internal communication between hardware components in transmitter (100). Furthermore, communicator (140) is configured to facilitate communication between transmitter (100) and other devices by means of one or more networks (e.g., wireless technology). Communicator (340) is configured for internal communication between hardware components in receiver (300). Furthermore, communicator (340) is configured to facilitate communication between receiver (300) and other devices by means of one or more networks (e.g., wireless technology). The communicators (140, 340) include electronic circuitry specific to standards that enable wired or wireless communication.

[0077] ARCCs (110, 310) are implemented by processing circuitry such as logic gates, integrated circuits, microprocessors, microcontrollers, memory circuits, passive electronic components, active electronic components, optical components, hardwired circuits, etc., and may optionally be driven by firmware. For example, the circuitry may be embodied in one or more semiconductor chips, or on a substrate support such as a printed circuit board.

[0078] In embodiments of this disclosure, the ARCC (110) estimates channel gain by transmitting pilot signals to the receiver (300) via each of the plurality of antennas of the transmitter (100) and the IRS (200). In embodiments of this disclosure, to estimate channel gain, the ARCC (110) transmits pilot signals to the receiver (300) via each of the plurality of antennas of the transmitter (100) by disabling the IRS (200). In response to the receiver (300) receiving the pilot signals, the ARCC (310) determines the location of the pilot signals based on the time and frequency of the pilot signals. Furthermore, the ARCC (310) estimates channel gain based on the pilot signals when the IRS (200) is disabled. Additionally, the ARCC (110) transmits pilot signals to the receiver (300) via each of the plurality of antennas of the transmitter (100) by enabling the IRS (200) and setting the reflection coefficient to one. In response to the receiver (300) receiving the pilot signal, the ARCC (310) estimates the channel gain based on the pilot signal when the IRS (200) is enabled. In addition, the ARCC (310) reports the estimated channel gain to the transmitter (100) when the IRS (200) is disabled and enabled.

[0079] The ARCC (110) determines an antenna selection metric based on the channel gain when transmitting pilot signals to the receiver (300) via each of the plurality of antennas of the transmitter (100) and the IRS (200). Furthermore, the ARCC (110) identifies from the plurality of antennas the antenna that provides the maximum antenna selection metric. Additionally, the ARCC (110) determines the reflection coefficient of each reflector of the IRS (200) based on the identified antenna. In embodiments of this disclosure, the reflection coefficient includes the magnitude of phase shift (θ) and reflection loss (β). Furthermore, the ARCC (110) configures the reflectors of the IRS (200) with the reflection coefficients. Finally, the ARCC (110) transmits signals to the receiver (300) via the identified antennas and the configured reflectors.

[0080] In another embodiment of this disclosure, the ARCC (310) estimates the channel gain by receiving pilot signals from each of the plurality of antennas of the transmitter (100) and the IRS (200). Furthermore, the ARCC (310) determines an antenna selection metric based on the channel gain received from each of the plurality of antennas of the transmitter (100) and the IRS (200). Furthermore, the ARCC (310) identifies from the plurality of antennas the antenna that provides the maximum antenna selection metric. Furthermore, the ARCC (310) determines the reflection coefficient of each reflector of the IRS (200) based on the identified antenna. Furthermore, the ARCC (310) reports the identified antenna and the reflection coefficient of each reflector to the transmitter (100). In response to receiving a report of the identified antenna and the reflection coefficient of each reflector from the receiver, the ARCC (110) configures the reflectors of the IRS (200) with the reflection coefficients and enables the transmitter (100) to transmit signals via the identified antenna.

[0081] In another embodiment of this disclosure, the ARCC (110) estimates a first channel gain by transmitting pilot signals to the receiver (300) via each of the plurality of antennas of the transmitter (100) and the IRS (200), wherein the reflection coefficient of each reflector of the IRS (200) is set to zero. In an embodiment of this disclosure, to estimate the first channel gain, the ARCC (110) transmits pilot signals to the receiver (300) via each of the plurality of antennas of the transmitter (100) by disabling the IRS (200). In response to receiving the pilot signals, the ARCC (310) determines the location of the pilot signals based on their time and frequency. Furthermore, the ARCC (310) estimates the first channel gain based on the pilot signals. Additionally, the ARCC (310) reports the first channel gain to the transmitter (100).

[0082] The ARCC (110) estimates the second channel gain by transmitting pilot signals to the receiver (300) via each of a plurality of antennas and an IRS (200), wherein the reflection coefficient of each reflector of the IRS (200) is set to one. In embodiments of this disclosure, to estimate the second channel gain, the ARCC (110) transmits pilot signals to the receiver (300) via each of a plurality of antennas of the transmitter (100) by enabling the IRS (200) and setting the reflection coefficient to one. In response to receiving the pilot signals, the ARCC (310) determines the location of the pilot signals based on the time and frequency of the pilot signals. Furthermore, the ARCC (310) estimates the second channel gain based on the pilot signals. Additionally, the ARCC (310) reports the second channel gain to the transmitter (100).

[0083] ARCC (110) determines the difference between the second channel gain and the first channel gain for each antenna. Furthermore, ARCC (110) determines the antenna among the plurality of antennas whose sum of the magnitude of the first channel gain and the magnitude of the difference between the second channel gain and the first channel gain is the largest. Additionally, ARCC (110) determines the reflection coefficient of each reflector in the IRS (200) by transmitting each pilot signal in the pilot signal set via the identified antenna and the IRS (200), wherein the number of pilot signals in the pilot signal set is equal to the number of reflectors in the IRS (200). Furthermore, ARCC (110) transmits signals to the receiver (300) via the identified antenna and the IRS (200) based on the reflection coefficients.

[0084] In another embodiment of this disclosure, the ARCC (310) estimates a first channel gain by receiving pilot signals from each of the plurality of antennas of the transmitter (100) and the IRS (200), wherein the reflection coefficient of each reflector of the IRS (200) is set to zero. Furthermore, the ARCC (310) estimates a second channel gain by receiving pilot signals from each of the plurality of antennas and the IRS (200), wherein the reflection coefficient of each reflector of the IRS (200) is set to one. Furthermore, the ARCC (310) determines the difference between the second channel gain and the first channel gain for each antenna. Additionally, the ARCC (310) determines the antenna among the plurality of antennas whose sum of the magnitude of the first channel gain and the magnitude of the difference between the second channel gain and the first channel gain is the largest. Furthermore, the ARCC (310) determines the reflection coefficient of each reflector in the IRS (200) by receiving each pilot signal from the set of pilot signals of the identified antenna and the IRS (200), wherein the number of pilot signals in the set of pilot signals is equal to the number of reflectors in the IRS (200). Additionally, the ARCC (310) reports the reflection coefficients of the identified antenna and each reflector to the transmitter (100).

[0085] In another embodiment of this disclosure, the ARCC (110) estimates channel gain by transmitting a pilot signal to the receiver (300) via an antenna set of multiple antennas of the transmitter (100) and an IRS (200). In an embodiment of this disclosure, the ARCC (110) transmits the pilot signal to the receiver (300) via an antenna set of multiple antennas of the transmitter (100) by disabling the IRS (200). In response to receiving the pilot signal, the ARCC (310) determines the location of the pilot signal based on the time and frequency of the pilot signal. Furthermore, when the IRS (200) is disabled, the ARCC (310) estimates the channel gain based on the pilot signal. The ARCC (110) transmits the pilot signal to the receiver (300) via an antenna set of multiple antennas of the transmitter (100) by enabling the IRS (200) and setting the reflection coefficient to one. Furthermore, in response to receiving the pilot signal, the ARCC (310) estimates the channel gain based on the pilot signal when the IRS (200) is enabled. In addition, the ARCC (310) reports the estimated channel gain to the transmitter (100) when the IRS (200) is disabled and enabled.

[0086] The ARCC (110) determines an antenna selection metric based on the channel gain when transmitting pilot signals to the receiver (300) via an antenna set from multiple antennas of the transmitter (100) and the IRS (200). Furthermore, the ARCC (110) identifies the antenna set from the multiple antennas that provides the maximum antenna selection metric. Additionally, the ARCC (110) determines the reflection coefficient of each reflector of the IRS (200) based on the antenna set. Furthermore, the ARCC (110) configures the reflectors of the IRS (200) using the reflection coefficients. Furthermore, the ARCC (110) determines the optimal beamforming required for transmitting signals from the antenna set based on the reflection coefficients and the antenna set. Furthermore, the ARCC (110) transmits signals to the receiver (300) via the configured reflectors and antenna set based on the optimal beamforming.

[0087] In another embodiment of this disclosure, the ARCC (310) estimates the channel gain by receiving pilot signals from an antenna set of multiple antennas of the transmitter (100) and an IRS (200). In this embodiment, to estimate the channel gain, the ARCC (310) receives pilot signals from the antenna set of multiple antennas of the transmitter (100) by disabling the IRS (200). Furthermore, the ARCC (310) determines the location of the pilot signals based on the time and frequency of the pilot signals. Furthermore, when the IRS (200) is disabled, the ARCC (310) estimates the channel gain based on the pilot signals. Furthermore, the ARCC (310) receives pilot signals from the antenna set of multiple antennas of the transmitter (100) by enabling the IRS (200) and setting the reflection coefficient to one. Furthermore, the ARCC (310) estimates the channel gain based on the pilot signals when the IRS (200) is enabled.

[0088] The ARCC (310) determines an antenna selection metric based on the channel gain when receiving pilot signals from the antenna set of multiple antennas from the transmitter (100) and the IRS (200). Furthermore, the ARCC (310) identifies the antenna set from the multiple antennas that provides the maximum antenna selection metric. Additionally, the ARCC (310) determines the reflection coefficient of each reflector of the IRS (200) based on the identified antenna set. Furthermore, the ARCC (310) reports the identified antenna set and the reflection coefficient of each reflector to the transmitter (100). In response to receiving the report from the receiver (300), the ARCC (110) configures the reflectors of the IRS (200) with the reflection coefficients and enables the transmitter (100) to transmit signals via the identified antenna set.

[0089] In another embodiment of this disclosure, the ARCC (110) estimates a first channel gain by transmitting pilot signals to the receiver (300) via each of the plurality of antennas of the transmitter (100) and the IRS (200), wherein the reflection coefficient of each reflector of the IRS (200) is set to zero. Furthermore, the ARCC (110) estimates a second channel gain by transmitting pilot signals to the receiver (300) via each of the plurality of antennas and the IRS (200), wherein the reflection coefficient of each reflector of the IRS (200) is set to one. Furthermore, the ARCC (110) determines the difference between the second channel gain and the first channel gain for each antenna. Furthermore, the ARCC (110) sorts each antenna in descending order of the difference between the second channel gain and the first channel gain. Furthermore, the ARCC (110) selects the first n antennas from the sorted antennas as an antenna set. Furthermore, the ARCC (110) transmits pilot signals via the selected antenna set. Furthermore, the ARCC (110) determines the reflection coefficient of each reflector of the IRS (200) based on the antenna set. Furthermore, the ARCC (110) configures the reflectors of the IRS (200) using the reflection coefficients. Furthermore, the ARCC (110) determines the optimal beamforming required for transmitting signals from the antenna set based on the reflection coefficients and the antenna set. Furthermore, the ARCC (110) transmits signals to the receiver (300) via the configured reflectors and antenna set based on the optimal beamforming.

[0090] In another embodiment of this disclosure, the ARCC (310) estimates a first channel gain by receiving pilot signals from each of the plurality of antennas of the transmitter (100) and the IRS (200), wherein the reflection coefficient of each reflector of the IRS (200) is set to zero. Furthermore, the ARCC (310) estimates a second channel gain by receiving pilot signals from each of the plurality of antennas and the IRS (200), wherein the reflection coefficient of each reflector of the IRS (200) is set to one. Furthermore, the ARCC (310) determines the difference between the second channel gain and the first channel gain for each antenna. Furthermore, the ARCC (310) sorts each antenna in descending order of the difference between the second channel gain and the first channel gain. Furthermore, the ARCC (310) selects the first n antennas from the sorted antennas as an antenna set. Furthermore, the ARCC (310) determines the reflection coefficient of each reflector of the IRS (200) based on the antenna set and the pilot signals transmitted by the transmitter (100). In addition, the ARCC (310) reports the selected first n antennas and the reflection coefficient of each reflector to the transmitter (100).

[0091] In another embodiment of this disclosure, both the transmitter (100) and the receiver (300) include a machine learning (ML) engine for determining the channel gain and the reflection coefficient of each reflector of the IRS (200). In embodiments of this disclosure, the ARCC (110, 310) monitors the estimated channel gain for at least one antenna at various times. Furthermore, the ARCC (110, 310) trains the ML engine to learn the estimated channel gain. Additionally, the ARCC (110, 310) predicts the channel gain when transmitting a pilot signal to the receiver (300) via at least one antenna based on the learning using the ML engine. In embodiments of this disclosure, the ARCC (110, 310) monitors the determined reflection coefficients at various times. Furthermore, the ARCC (110, 310) trains the ML engine to learn the determined reflection coefficients. Additionally, the ARCC (110, 310) predicts the reflection coefficient of each reflector of the IRS (200) based on the learning using the ML engine.

[0092] At least one of the multiple modules can be implemented via the ML engine. Functions associated with the ML engine can be executed via non-volatile memory, volatile memory, and processors (130, 330).

[0093] One or more processors control the processing of input data based on predefined operating rules or an ML engine stored in non-volatile and volatile memory. The predefined operating rules or artificial intelligence model are provided through training or learning.

[0094] Here, "learning by providing" means that predefined operational rules or an ML engine with desired characteristics are made by applying learning techniques to multiple learning data. Learning can be performed within the apparatus in which the ML engine according to the embodiment is executed, and / or it can be implemented via a separate server / system.

[0095] ML engines can consist of multiple neural network layers. Each layer has multiple weight values, and layer operations are performed by computing the previous layer and operating on the multiple weights. Examples of neural networks include, but are not limited to, Convolutional Neural Networks (CNNs), Deep Neural Networks (DNNs), Recurrent Neural Networks (RNNs), Restricted Boltzmann Machines (RBMs), Deep Belief Networks (DBNs), Bidirectional Recurrent Deep Neural Networks (BRDNNs), Generative Adversarial Networks (GANs), and Deep Q-Networks.

[0096] Learning techniques are methods for training a predetermined target device (e.g., a robot) using multiple learning data sets to enable, allow, or control the target device to make determinations or predictions. Examples of learning techniques include, but are not limited to, supervised learning, unsupervised learning, semi-supervised learning, or reinforcement learning.

[0097] although Figure 1 The hardware components of the electronic device (100) are shown, but it should be understood that other embodiments are not limited thereto. In other embodiments of this disclosure, the electronic device (100) may include fewer or more components. Furthermore, the labels or names of the components are for illustrative purposes only and do not limit the scope of this disclosure. One or more components can be combined to perform the same or substantially similar functions in order to enhance the power of the signal received at the receiver (300).

[0098] Figure 2A This is a flowchart (A200) illustrating a method for enhancing the power of a signal received at a receiver using an IRS according to an embodiment of the present disclosure.

[0099] Reference Figure 2A This method allows the ARCC (110) to perform operations A201-A206 of flowchart (A200). In operation A201, the method includes estimating channel gain by transmitting pilot signals to the receiver (300) via each of the plurality of antennas of the transmitter (100) and the IRS (200). In operation A202, the method includes determining an antenna selection metric based on the channel gain when transmitting pilot signals to the receiver (300) via each of the plurality of antennas of the transmitter (100) and the IRS (200).

[0100] In operation A203, the method includes: identifying an antenna from a plurality of antennas that provides the maximum antenna selectivity metric. In operation A204, the method includes: determining the reflection coefficient of each reflector of the IRS (200) based on the identified antenna. In operation A205, the method includes: configuring the reflectors of the IRS (200) with the reflection coefficients. In operation A206, the method includes: transmitting a signal to a receiver (300) via the identified antenna and the configured reflectors.

[0101] Figure 2B This is a flowchart (B200) illustrating a method for enhancing the power of a signal received at a receiver using an IRS according to an embodiment of the present disclosure.

[0102] Reference Figure 2BThis method allows the ARCC (110) to perform operations B201-B206 of flowchart (B200). In operation B201, the method includes estimating a first channel gain by transmitting pilot signals to the receiver (300) via each of the plurality of antennas of the transmitter (100) and the IRS (200), wherein the reflection coefficient of each reflector of the IRS (200) is set to zero. In operation B202, the method includes estimating a second channel gain by transmitting pilot signals to the receiver (300) via each of the plurality of antennas and the IRS (200), wherein the reflection coefficient of each reflector of the IRS (200) is set to one.

[0103] In operation B203, the method includes: determining the difference between a second channel gain and a first channel gain for each antenna. In operation B204, the method includes: determining the antenna among a plurality of antennas whose sum of the magnitudes of the first channel gain and the difference between the second channel gain and the first channel gain is the largest. In operation B205, the method includes: determining the reflection coefficient of each reflector of the IRS (200) by transmitting each pilot signal in the pilot signal set via the identified antenna and the IRS (200), wherein the number of pilot signals in the pilot signal set is equal to the number of reflectors in the IRS (200). In operation B206, the method includes: transmitting a signal to a receiver (300) via the identified antenna and the IRS (200) based on the reflection coefficient.

[0104] Figure 2C This is a flowchart (C200) illustrating a method for enhancing the power of a signal received at a receiver using an IRS according to an embodiment of the present disclosure.

[0105] Reference Figure 2C This method allows the ARCC (110) to perform operations C201-C207 of flowchart (C200). In operation C201, the method includes estimating channel gain by transmitting pilot signals to the receiver (300) via an antenna set of a plurality of antennas of the transmitter (100) and an IRS (200). In operation C202, the method includes determining an antenna selection metric based on the channel gain when transmitting pilot signals to the receiver (300) via an antenna set of a plurality of antennas of the transmitter (100) and an IRS (200).

[0106] In operation C203, the method includes: identifying an antenna set from a plurality of antennas that provides the maximum antenna selectivity metric. In operation C204, the method includes: determining the reflection coefficient of each reflector of the IRS (200) based on the antenna set. In operation C205, the method includes: configuring the reflectors of the IRS (200) with the reflection coefficients. In operation C206, the method includes: determining the optimal beamforming required to transmit a signal from the antenna set based on the reflection coefficients and the antenna set. In operation C207, the method includes: transmitting a signal to a receiver (300) via the configured reflectors and antenna set based on the optimal beamforming.

[0107] Figure 2D This is a flowchart (D200) illustrating a method for enhancing the power of a signal received at a receiver using an IRS according to an embodiment of the present disclosure.

[0108] Reference Figure 2D This method allows the ARCC (110) to perform operations D201-D210 of flowchart (D200). In operation D201, the method includes estimating a first channel gain by transmitting pilot signals to a receiver (300) via each of a plurality of antennas of the transmitter (100) and the IRS (200), wherein the reflection coefficient of each reflector of the IRS (200) is set to zero. In operation D202, the method includes estimating a second channel gain by transmitting pilot signals to the receiver (300) via each of a plurality of antennas and the IRS (200), wherein the reflection coefficient of each reflector of the IRS (200) is set to one. In operation D203, the method includes determining the difference between the second channel gain and the first channel gain for each antenna. In operation D204, the method includes sorting each antenna in descending order of the difference between the second channel gain and the first channel gain.

[0109] In operation D205, the method includes: selecting the first n antennas from the sorted antennas as an antenna set. In operation D206, the method includes: transmitting a pilot signal via the selected antenna set. In operation D207, the method includes: determining the reflection coefficient of each reflector of the IRS (200) based on the antenna set. In operation D208, the method includes: configuring the reflectors of the IRS (200) with the reflection coefficients. In operation D209, the method includes: determining the optimal beamforming required for transmitting a signal from the antenna set based on the reflection coefficients and the antenna set. In operation D210, the method includes: transmitting a signal to a receiver (300) via the configured reflectors and antenna set based on the optimal beamforming.

[0110] Figure 3AThis is a flowchart (A300) illustrating a method for enhancing the power of a signal received at a receiver using an IRS according to an embodiment of the present disclosure.

[0111] Reference Figure 3A This method allows the ARCC (310) to perform operations A301-A305 of flowchart (A300). In operation A301, the method includes: estimating channel gain by receiving pilot signals from each of a plurality of antennas of the transmitter (100) and the IRS (200). In operation A302, the method includes: determining an antenna selection metric based on the channel gain when receiving pilot signals from each of the plurality of antennas of the transmitter (100) and the IRS (200). In operation A303, the method includes: identifying from the plurality of antennas an antenna that provides the maximum antenna selection metric. In operation A304, the method includes: determining the reflection coefficient of each reflector of the IRS (200) based on the identified antenna. In operation A305, the method includes: reporting the identified antenna and the reflection coefficient of each reflector to the transmitter (100) so as to configure the reflectors of the IRS (200) with the reflection coefficients and enable the transmitter (100) to transmit signals via the identified antenna.

[0112] Figure 3B This is a flowchart (B300) illustrating a method for enhancing the power of a signal received at a receiver (300) using an IRS according to an embodiment of the present disclosure.

[0113] Reference Figure 3B This method allows the ARCC (310) to perform operations B301-B306 of flowchart (B300). In operation B301, the method includes: estimating a first channel gain by receiving pilot signals from each of the plurality of antennas of the transmitter (100) and the IRS (200), wherein the reflection coefficient of each reflector of the IRS (200) is set to zero. In operation B302, the method includes: estimating a second channel gain by receiving pilot signals from each of the plurality of antennas and the IRS (200), wherein the reflection coefficient of each reflector of the IRS (200) is set to one.

[0114] In operation B303, the method includes: determining the difference between a second channel gain and a first channel gain for each antenna. In operation B304, the method includes: identifying the antenna among a plurality of antennas whose sum of the magnitude of the first channel gain and the magnitude of the difference between the second channel gain and the first channel gain is the largest. In operation B305, the method includes: determining the reflection coefficient of each reflector of the IRS (200) by receiving each pilot signal from the identified antenna and the pilot signal set of the IRS (200), wherein the number of pilot signals in the pilot signal set is equal to the number of reflectors in the IRS (200). In operation B306, the method includes: reporting the identified antenna and the reflection coefficient of each reflector to the transmitter (100) so as to configure the reflectors of the IRS (200) with the reflection coefficients and enable the transmitter (100) to transmit signals via the identified antenna.

[0115] Figure 3C This is a flowchart (C300) illustrating a method for enhancing the power of a signal received at a receiver using an IRS according to an embodiment of the present disclosure.

[0116] Reference Figure 3C This method allows the ARCC (310) to perform operations C301-C305 of flowchart (C300). In operation C301, the method includes estimating channel gain by receiving pilot signals from an antenna set of multiple antennas of the transmitter (100) and the IRS (200). In operation C302, the method includes determining an antenna selection metric based on the channel gain when receiving pilot signals from the antenna set of multiple antennas of the transmitter (100) and the IRS (200).

[0117] In operation C303, the method includes: identifying an antenna set from a plurality of antennas that provides a maximum antenna selectivity metric. In operation C304, the method includes: determining the reflection coefficient of each reflector of the IRS (200) based on the identified antenna set. In operation C305, the method includes: reporting the identified antenna set and the reflection coefficient of each reflector to a transmitter (100) so as to configure the reflectors of the IRS (200) with the reflection coefficients and enable the transmitter (100) to transmit signals via the identified antenna set.

[0118] Figure 3D This is a flowchart (D300) illustrating a method for enhancing the power of a signal received at a receiver using an IRS according to an embodiment of the present disclosure.

[0119] Reference Figure 3DThis method allows the ARCC (310) to perform operations D301-D307 of flowchart (D300). In operation D301, the method includes: estimating a first channel gain by receiving pilot signals from each of the plurality of antennas of the transmitter (100) and the IRS (200), wherein the reflection coefficient of each reflector of the IRS (200) is set to zero. In operation D302, the method includes: estimating a second channel gain by receiving pilot signals from each of the plurality of antennas and the IRS (200), wherein the reflection coefficient of each reflector of the IRS (200) is set to one. In operation D303, the method includes: determining the difference between the second channel gain and the first channel gain for each antenna.

[0120] In operation D304, the method includes: sorting each antenna in descending order of the difference between the second channel gain and the first channel gain. In operation D305, the method includes: selecting the first n antennas from the sorted antennas as an antenna set. In operation D306, the method includes: determining the reflection coefficient of each reflector of the IRS (200) based on the antenna set and the pilot signal transmitted by the transmitter (100). In operation D307, the method includes: reporting the selected first n antennas and the reflection coefficient of each reflector to the transmitter (100) so as to configure the reflectors of the IRS (200) with the reflection coefficients and enable the transmitter (100) to transmit signals via the identified antennas.

[0121] Various actions, behaviors, boxes, steps, etc., in the flowcharts (A200, B200, C200, D200, A300, B300, C300, D300) can be executed in the presented order, in different orders, or simultaneously. Furthermore, in some embodiments of this disclosure, some actions, behaviors, boxes, steps, etc., can be omitted, added, modified, or skipped without departing from the scope of this disclosure.

[0122] Reference Figure 1 In the example scenario describing the proposed method, a channel model is considered, namely a quasi-static flat attenuation channel model. Furthermore, the operating mode considered in this example scenario is a time-division duplex (TDD) operating mode that utilizes reciprocity and reduces CSI feedback overhead. Let... Let represent the complex baseband channel gain vector from IRS(200) to receiver(300). and Let S represent the complex baseband channel gain vector from transmitter (100) to receiver (300) and the complex channel gain matrix from transmitter (100) to IRS (200), respectively. Let S denote that each contains N RF A set of n elements {1,2,...,N}t The set of all possible subsets of}. Let S∈S denote the set containing the selected N. RF A subset of the indices of each antenna. Let This represents the channel gain vector from transmitter (100) to receiver (300) corresponding to subset S, and This represents a submatrix in S containing columns of G corresponding to the antenna indices. The reflection coefficient of the nth IRS reflector is given by x. n =βe jθn It is represented that θ n Let ∈[0,2π] and β∈[0,1] be the phase shift and reflection loss of the nth IRS reflector. Let It is the passive beamforming vector at IRS(200) and This represents the transmitted beamforming vector at the transmitter (100).

[0123] The transmitter uses a subset S of its antennas to transmit data symbol d. The receiver then receives the signal via a direct link from the transmitter to the receiver. Transmitted from antenna k and through the application of reflection coefficient x n Observation of the cascaded channel of the signal reflected by the nth IRS reflector Therefore, the receiver receives via the reflection link (i.e., the link from the transmitter to the IRS and then to the receiver). The composite signal received by all selected antennas and all IRS reflectors can be written as of Given, among which Indicates by element The diagonal matrix is ​​represented by its diagonal elements. Therefore, Equation 1 gives the signal y received at the receiver via the direct link and the reflected link.

[0124] [math Figure 1 ]

[0125]

[0126] in And z indicates that the receiver (300) has zero mean and zero variance σ. 2 Additive white Gaussian noise.

[0127] Consider the transmitter (100) knowing the direct link channel gain vector of the link channel between the transmitter (100) and the receiver (300). and the cascaded gain matrix H of the reflection link channel rG. The transmitter (100) uses a two-stage approach to estimate these channel gains at the transmitter (100) using pilot symbols transmitted from the receiver (300). In the first stage, the IRS (200) is turned off and the transmitter (100) estimates the direct link channel gain. In the second stage, the IRS (200) is turned on and the transmitter (100) estimates the sum of the direct link channel gain and the reflected link channel gain, which can be accomplished by turning on only one IRS reflector at a time or by turning on all IRS reflectors and using the rows of the Discrete Fourier Transform (DFT) matrix as the passive beamforming vector. Individual channel gains from transmitter (100) to IRS (200) and from IRS (200) to receiver (300), which are difficult to obtain due to the passive nature of the IRS (200), are not assumed at the transmitter (100). Furthermore, CSI is not assumed at either the IRS (200) or the receiver (300). The transmitter (100) calculates the passive beamforming vector x based on the acquired CSI and communicates with the IRS (200) controller via a control link.

[0128] According to Equation 1, Equation 2 gives the instantaneous signal-to-noise ratio (SNR) at the receiver (300) when the transmitter (100) transmits using a subset S with a transmit beamforming vector w and the IRS (200) adopts a passive beamforming vector x.

[0129] [Mathematical Figure 2]

[0130]

[0131] Let R(S,w,x) represent the instantaneous velocity as given in Equation 3.

[0132] [Mathematical Figure 3]

[0133] R(S,w,x)=log2(1+SNR(S,w,x))

[0134] Similarly, Equation 4 gives the symbol error probability SEP(S,w,x) at the receiver (300).

[0135] [math Figure 4 ]

[0136] SEP(S,w,X)=c1exp(-c2SNR(S,w,x))

[0137] According to Equation 4, it is clear that maximizing the instantaneous SNR will maximize the instantaneous rate and minimize the symbol error probability. The main objective of this disclosure is to maximize the SNR at the receiver (300). The transmitter (100) is subject to a peak transmit power constraint, which will be derived from the selected N... RFThe total instantaneous power of each antenna is limited to below the maximum allowed total transmit power P. max That is, ||w|| 2 ≤P max When the goal is to maximize signal power, the reflection loss β is set to 1. Therefore, the modulus of each reflection coefficient at IRS(200) is one, i.e., |x n |=1, This is often referred to as the unity modulus constraint. Another objective is to jointly solve for a subset S of the antenna, the transmit beamforming vector w at the transmitter (100), and the passive beamforming vector x at the IRS (200) to maximize the received SNR while satisfying both peak transmit power and unity modulus constraints. Optimization is performed on a size N... RF Complex vectors {w∈C} NRF×1 :||w|| 2 ≤P max}and The optimization P required in the system can be written out as in Equation 5, based on the space of discrete sets.

[0138] [Mathematical Figure 5]

[0139]

[0140] [math Figure 6 ]

[0141] Obey ||w|| 2 ≤P max

[0142] [math Figure 7 ]

[0143]

[0144] Since the objective function is non-concave and the unity modulus constraint is non-convex, the optimization of P is non-convex in nature. The proposed method achieves low channel estimation overhead and computational complexity for single antenna selection (N... RF =1) Scene and subset antenna selection (N RF >1) The scenario provides optimized P.

[0145] Figure 4 This is a schematic diagram illustrating a single antenna selection and passive beamforming for delivering a signal to a receiver according to an embodiment of the present disclosure.

[0146] Reference Figure 4 Let s∈{1,2,...,N} t} represents the index of the selected antenna. Here, the received signal in Equation 1 is reduced as in Equation 8.

[0147] [math Figure 8 ]

[0148]

[0149] For an IRS (200) assisted communication system with a single antenna selection at the transmitter (100), the optimal antennas for optimal passive beamforming are given in Equations 9, 10, and 11, respectively. * Transmission power and reflection coefficient

[0150] [Mathematical Figure 9]

[0151]

[0152] [Mathematical Figure 10]

[0153]

[0154] [Mathematical Figure 11]

[0155]

[0156] The selection metric for each antenna is the sum of the absolute values ​​of the direct link channel gain and the channel gains of the N reflective links. The optimal antenna is the one with the highest selection metric, and the method for selecting the optimal antenna is called the optimal AS method. The optimal reflection coefficient of each IRS reflector depends on the phase difference between the direct link and the reflective links. The optimal antenna depends only on the absolute value of the channel gain, while the optimal reflection coefficient depends only on their phase.

[0157] Figure 5A and Figure 5B These are schematic diagrams (501, 502) illustrating methods for estimating direct link channel gain and reflected link channel gain according to embodiments of the present disclosure.

[0158] Reference Figure 5A and Figure 5B The transmitter (100) uses a two-stage approach to estimate the direct link channel gain and the reflected link channel gain using pilot symbols transmitted from the receiver (300). In the first stage, the IRS (200) is turned off, i.e., β n =0, and the transmitter (100) transmits N t A pilot signal is used to measure N. t The antennas are used to estimate the direct link channel gain. In the second stage, the IRS (200) is turned on and the transmitter (100) transmits N... tN pilot signals are used to estimate the channel gain of the reflection link. The transmitter (100) has only one RF chain. Therefore, in order to estimate the channel gain, the transmitter (100) switches the RF chain to each antenna. Therefore, the receiver (300) needs to transmit N pilot signals in the first stage. t A pilot signal is used to estimate the direct link channel gain, while N signals are transmitted in the second stage. t N pilot signals are used to estimate the reflection link channel gain. The transmitter (100) uses a total of N pilot signals. t +N t N pilot signals are required. Furthermore, O(N) time is needed. t N+N t The calculation is performed several times to select the best antenna and calculate its optimal reflection coefficient.

[0159] In embodiments of this disclosure, an improved pilot transmission scheme is proposed, wherein the improved pilot transmission scheme includes three stages as described below. In the first stage, the IRS (200) is de-energized (β). n =0) and the transmitter (100) measures the direct link channel gain. In the second stage, the IRS (200) is powered on and the transmitter (100) measures the reflected link channel gain. In addition, the transmitter (100) sets β n =1 and θ n =0 to configure x n =1. The transmitter (100) transmits one signal instead of N via the transmitting antenna. t N pilot signals. This will still make it possible to measure the absolute reflected channel gain of each transmit antenna in order to select the antenna. In the third stage, the transmitter (100) transmits N pilot signals to the receiver (300) via the IRS reflector to estimate the channel gain from the selected transmit antenna. The number of pilots used to measure the direct link channel gain, reflected link channel gain, and phase is N. t N t N. A total of 2N was used. t +N pilot signals, which reduces the overall computational complexity.

[0160] In another embodiment of this disclosure, the method involves selecting an amount (That is, the sum of the absolute channel gain from transmitter (100) to receiver (300) and the sum of the absolute values ​​of the composite channel gains from transmitter (100) to IRS (200) and from IRS (200) to receiver (300) is maximized to reduce channel estimation overhead and computational complexity. This is called the Low Complexity AS (LAS) rule, and Equation 12 is formed by lowering the optimal selection metric for antenna k given in Equation 9. Then, the reflection coefficient calculated for the selected antenna according to Equation 11 is given in Equation 13. The IRS reflectors are configured by selecting the phase factor of each IRS reflector as the difference between the phase of the selected antenna channel from transmitter (100) to receiver (300) and the phase of the composite channel from transmitter (100) to IRS (200) and from IRS (200) to receiver (300).

[0161] [Mathematical Figure 12]

[0162]

[0163] [Mathematical Figure 13]

[0164]

[0165] For each antenna k, the transmitter (100) only needs to know the sum of the reflection link channel gains, which can be achieved by sending a pilot signal from the receiver (300) and configuring x. n =1, To estimate directly. Therefore, the receiver (300) only needs to send N t pilots to obtain Instead of sending the N required for the selection metric of the best rule t N pilot signals. Furthermore, calculate the channel gain of the N reflection links corresponding to the selected antenna. We need to calculate x n This requires N pilots. Therefore, only 2N are needed. t +N pilots instead of N t +N t N pilots are required. Therefore, this method significantly reduces the estimation overhead. Furthermore, determining the AS and reflection coefficient requires only O(N) pilots. t +N) calculations.

[0166] Reference Figure 1 The method for selecting the optimal antenna set is described below. For a given subset S of antennas and a passive beamforming vector x, the optimal beamforming vector w at the transmitter (100) is... opt It is given by the maximum ratio transmission (MRT) in Equation 14.

[0167] [Mathematical Figure 14]

[0168]

[0169] Substituting Equation 14 into Equation 5 yields the signal power.

[0170] Therefore, for a given subset S, the transmitter (100) determines x that maximizes the signal power by solving the following optimization problem given in Equation 15.

[0171] [Mathematical Figure 15]

[0172]

[0173] [Mathematical Figure 16]

[0174] obey

[0175] P S The objective function in x is quadratic and convex. However, the unit modulus constraint is non-convex. Therefore, standard convex optimization techniques cannot be used. The aforementioned unit modulus constraint defines the Riemannian manifold. Therefore, P can be solved efficiently using manifold optimization techniques and alternating optimization techniques. S .

[0176] The Subset Selection Based on Manifold Optimization (MOBSS) method is a manifold optimization technique used by the emitter (100). For each S∈S, the MOBSS method can be used to solve P. S In order to obtain the passive beamforming vector z S and the corresponding signal power. Optimal subset S opt It generates the maximum signal power and the optimal passive beamforming vector x. opt =z Sopt A subset of. By substituting S into Equation 14 opt and x opt The optimal beamforming vector w was further determined. opt The MOBSS method is based on exhaustive search. The steps in the MOBSS method are given below.

[0177] Step-1: Transmitter (100) estimates N t Direct link channel gain and N t N reflection link channel gains.

[0178] Step-2: For all S∈do

[0179] To obtain the solution of P using manifold optimization techniques S z S .

[0180] Step 3: End for

[0181]

[0182] Step-4: x opt =zS opt .

[0183] Step 5: Substitute S into Equation 14 opt and x opt To calculate w opt .

[0184] Step 6: Return to S opt w opt x opt .

[0185] The transmitter (100) has N RF RF chains are needed. Using pilot signals to estimate N t One direct link channel gain, while for the reflected link channel gain, it is necessary to One pilot. This MOBSS method is for those containing For each element S∈S, solve P. S For each element, the emitter (100) uses the MOBSS method to solve the optimization problem, which requires O(N) time complexity. x ) calculations. Therefore, the total computational complexity is .

[0186] The Alternating Optimization-Based Subset Selection (AOBSS) method is an alternating optimization technique used by the transmitter (100). To reduce the computational complexity involved in the MOBSS method, the transmitter (100) developed an order-based subset selection method. For each antenna k, the transmitter (100) first calculates the selection metric of the LAS rule in Equation 12, i.e., And sort them in descending order. Then, the transmitter (100) selects the top N from the sorted list. RF The antennas are used as a subset S for transmission. For this subset S, the transmitter (100) uses the AOBSS method to iteratively solve for w and x. The transmitter (100) initializes w with the MRT-based beamforming vector in the direct link direction, i.e., Given a subset S and a beamforming vector This is the effective direct link channel gain from transmitter (100) to receiver (300). Similarly, [G S w] n This is the effective channel gain from the transmitter (100) to the nth IRS reflector. For these effective channel gains, according to Equation 11, the transmitter (100) knows that the optimal passive beamforming reflection coefficient is given by the following equation:

[0187] [Mathematical Figure 17]

[0188]

[0189] The transmitter (100) then updates w by substituting the passive beamforming vector calculated above into Equation 14. The transmitter (100) then calculates the optimal x for this updated w and continues iterating until convergence. Here, in each iteration, the transmitter (100) alternately optimizes x for a given w, and then optimizes w for a given x. The steps in the low-complexity subset antenna selection method based on alternating optimization are given below.

[0190] Step 1: Estimate the CSI required to calculate the selected metric.

[0191] Step 2: For k∈{1,2,...,N} t Select metrics in descending order. Sort them.

[0192] Step 3: Select the top N values ​​from the sorted list. RF The indices of the antennas are assigned to the subset S.

[0193] Step 4: Estimate the CSI of the reflected link corresponding to the subset of selected antennas.

[0194] Step 5: Initialize m = 0,

[0195] while (SNR improvement > ε) and (m ≤ MAXITER) do

[0196] Update m = m + 1.

[0197]

[0198] x m = [x1, x2, ..., x N ].

[0199]

[0200] end while.

[0201] Step 6:

[0202] Step 7: x m+1 =[x1,x2,...,x N ].

[0203] Step 8: Return to S, w m+1 and x m+1 .

[0204] Similarly, in the AOBSS method, as with the MOBSS method, the transmitter (100) uses direct link CSI. One pilot. However, the transmitter (100) uses a selection metric from the LAS rules and requires... One pilot is needed to obtain the reflection link CSI required for calculating the selection metric, and N pilots are needed to calculate the IRS(200) reflection coefficient. In summary, the transmitter (100) uses... Each method generates one pilot. Then, selecting a subset requires O(Nt log(Nt)) computations, and each iteration requires O(N) computations to compute w and x. Therefore, compared to the MOBSS method, the AOBSS method significantly reduces the required computational complexity and the number of pilot transmissions. Table 1 compares the computational complexity and number of pilot transmissions required by the proposed method with existing semi-finite relaxation (SDR) methods.

[0205] [Table 1]

[0206]

[0207] Figure 6 This illustrates how the average symbol error probability (SEP) is plotted as peak transmit power (P) for different numbers of IRS reflectors according to embodiments of the present disclosure. max A graphical representation of the function. In the example scenario, a uniform linear array with half-wavelength antenna spacing at the transmitter (100) and a uniform planner array at the IRS (200) are used to evaluate the performance of the proposed method. The transmitter (100) and the IRS (200) are positioned such that there is a dominant line-of-sight (LOS) component between them. Therefore, the channel gain model between the transmitter (100) and the IRS (200) is modeled as in Equation 18.

[0208] [Mathematical Figure 18]

[0209]

[0210] Among them, G LOS and G NLOS These represent the LOS component and the non-LOS component, respectively. K represents the Rician factor, which is set to 10. In the example scenario, for G... NLOS The direct link from transmitter (100) to receiver (300) and the link from IRS (200) to receiver (300) take into account independent Rayleigh fading. Let d bi d bu and d iuLet represent the distances from transmitter (100) to IRS (200), from transmitter (100) to receiver (300), and from IRS (200) to receiver (300), respectively. The path loss from transmitter (100) to IRS (200), from transmitter (100) to receiver (300), and from IRS (200) to receiver (300) are considered to be 16.6 + 22log 10 (d bi ), 35+30log 10 (d bu ) and 20+30log 10 (d iu ). σ 2 It was set to -80dBm.

[0211] Reference Figure 6 The performance of the optimal AS method and the LAS rule was compared. The average SEP increased with P. max The power increases while decreasing because the transmitter (100) is allowed to transmit at higher power. The LAS rule with low computational complexity and channel estimation overhead is close to optimal. Furthermore, the average SEP of the transmitter (100) with a single antenna is significantly higher than that of the transmitter (100) with four antennas and an RF chain. For example, in P... max At 6 dB, the average SEP was 8.1 times and 23.8 times higher for N=25 and N=75, respectively. Furthermore, the average SEP decreased significantly with increasing N. At P max At 6dB, the average SEP of N=75 was 58.1 times lower than that of N=25.

[0212] Figure 7 This illustrates how, according to embodiments of the present disclosure, the SNR at the receiver is plotted as the distance d between the receiver and the transmitter for different numbers of IRS reflectors. bu The graph of the function.

[0213] Reference Figure 7 The distance d between the transmitter (100) and the IRS (200) bi The distance is fixed at 40 meters, and the receiver (300) moves parallel to the line connecting the transmitter (100) and the IRS (200). When N t =4 and N RF When d = 2, the SNR performance of the proposed subset antenna selection method is compared with that of SDR-based beamforming techniques requiring all four RF chains. Furthermore, when there is no IRS(200), the SNR increases with d bu It decreases as it increases. However, in the case of IRS(200), SNR initially decreases as d increases. buIncrease and then decrease, then increase until d. bu =40m. This occurs because as the receiver (300) moves away from the transmitter (100), it moves closer to the IRS (200), which strengthens the reflection link. Furthermore, as both the receiver (300) and the IRS (200) move away, for d... bu >40 meters, SNR decreases. SNR is maximized when the receiver (300) is close to the IRS (200). The greatest benefit of increasing N occurs at d. bu At a distance of 40 meters, the SNR increased by 6 dB by doubling the number of IRS(200) reflectors. Therefore, the placement of the IRS(200) plays a crucial role in SNR performance. Regardless of the low complexity and channel estimation overhead of the AOBSS method, its performance is very close to that of the MOBSS method. Furthermore, the proposed method achieves an SNR close to that of SDR-based beamforming techniques that require two additional RF chains. bu At 40m, the SNR loss due to less hardware is only 1.72dB and 2.2dB for N=50 and N=100, respectively.

[0214] Figure 8 This is a graphical representation of the average SEP as a function of peak transmit power for different numbers of antennas at the transmitter, according to embodiments of the present disclosure. For this plot, N RF It was set to 2.

[0215] Reference Figure 8 ,exist Figure 8 The average SEP performance of the MOBSS and AOBSS methods was compared, and they were very close. The AOBSS method is both simple and a near-optimal subset selection method. By increasing the number of antennas with the same number of RF chains, the average SEP is significantly reduced. For example, in P... max When it reaches 4dBm, it is in N t =4 and N t =8, which decreased by 3.6 times and 24.4 times respectively.

[0216] Although this disclosure has been shown and described with reference to various embodiments thereof, those skilled in the art will understand that various changes in form and detail may be made therein without departing from the spirit and scope of this disclosure as defined by the appended claims and their equivalents.

Claims

1. A method for using a smart reflective surface (IRS) to enhance the power of a signal in a wireless communication system, the method comprising: The transmitter of the wireless communication system estimates the channel gain by transmitting pilot signals to the receiver via at least one of the transmitter's multiple antennas and the IRS; The transmitter determines an antenna selection metric based on the channel gain when transmitting the pilot signal to the receiver via at least one of the plurality of antennas of the transmitter and the IRS; The transmitter identifies from the plurality of antennas at least one antenna that provides the maximum antenna selection metric; The transmitter determines the reflection coefficient of each reflector of the IRS based on the identified antenna; The transmitter uses the reflection coefficient to configure the reflector of the IRS; as well as The transmitter transmits signals to the receiver via at least one identified antenna and a configured reflector.

2. The method according to claim 1, wherein, Determining the antenna selection metric includes: The transmitter estimates the first channel gain by transmitting the pilot signal to the receiver via at least one of the plurality of antennas of the transmitter and the IRS, wherein the reflection coefficient of each reflector of the IRS is set to zero; The transmitter estimates the second channel gain by transmitting the pilot signal to the receiver via at least one of the plurality of antennas and the IRS, wherein the reflection coefficient of each reflector of the IRS is set to one; The transmitter determines the difference between the second channel gain and the first channel gain for the at least one antenna; and The transmitter identifies at least one antenna from the plurality of antennas whose sum of the magnitude of the first channel gain and the magnitude of the difference between the second channel gain and the first channel gain is the largest.

3. The method according to claim 2, in, The transmitter estimates a first channel gain by transmitting the pilot signal to the receiver via at least one of the plurality of antennas of the transmitter and the IRS, wherein the reflection coefficient of each reflector of the IRS is set to zero, including: The receiver receives the pilot signal from at least one of the plurality of antennas of the transmitter, wherein the IRS is disabled; In response to receiving the pilot signal, the receiver determines the location of the pilot signal based on the time and frequency of the pilot signal; The receiver estimates the first channel gain based on the pilot signal; and The receiver reports the first channel gain to the transmitter.

4. The method according to claim 2, in, The transmitter estimates the second channel gain by transmitting the pilot signal to the receiver via at least one of the plurality of antennas and the IRS, wherein the reflection coefficient of each reflector of the IRS is set to one, including: The receiver receives the pilot signal from at least one of the plurality of antennas of the transmitter, wherein the IRS is enabled and the reflection coefficient is set to one; In response to receiving the pilot signal, the receiver determines the location of the pilot signal based on the time and frequency of the pilot signal; The receiver estimates the second channel gain based on the pilot signal; and The receiver reports the second channel gain to the transmitter.

5. The method according to claim 1, further comprising: The transmitter determines the optimal beamforming required to transmit a signal from the at least one antenna based on the reflection coefficient and the at least one antenna. as well as The transmitter transmits a signal to the receiver via the configured reflector and the at least one antenna based on the optimal beamforming.

6. The method according to claim 1, wherein, Estimating the channel gain includes: The receiver receives the pilot signal from at least one of the plurality of antennas of the transmitter, wherein the IRS is disabled; In response to receiving the pilot signal, the receiver determines the location of the pilot signal based on the time and frequency of the pilot signal; When the IRS is disabled, the receiver estimates the channel gain based on the pilot signal; The receiver receives the pilot signal from at least one of the plurality of antennas of the transmitter, wherein the IRS is enabled and the reflection coefficient is set to one; When the IRS is enabled, the receiver estimates the channel gain based on the pilot signal; and The receiver reports the estimated channel gain to the transmitter when the IRS is disabled and enabled.

7. The method according to claim 1, wherein, Estimating the channel gain includes: The transmitter monitors the estimated channel gain for the at least one antenna at various times; The transmitter trains a machine learning (ML) engine to learn the estimated channel gain; and The transmitter predicts the channel gain when transmitting the pilot signal to the receiver via the at least one antenna based on learning using the ML engine.

8. The method according to claim 1, wherein, Determining the reflection coefficient of each reflector of the IRS includes: The transmitter listens to the reflection coefficient determined at each moment; The transmitter trains the ML engine to learn the reflection coefficients determined at various times; and The transmitter predicts the reflection coefficient of each reflector of the IRS based on learning using the ML engine.

9. A method for using a smart reflective surface (IRS) to enhance the power of a signal in a wireless communication system, the method comprising: The receiver estimates the channel gain by receiving pilot signals from at least one of the multiple antennas of the transmitter of the wireless communication system and the IRS; The receiver determines an antenna selection metric based on the channel gain when receiving the pilot signal from at least one of the plurality of antennas of the transmitter and the IRS; The receiver identifies from the plurality of antennas at least one antenna that provides the maximum antenna selection metric; The receiver determines the reflection coefficient of each reflector of the IRS based on at least one identified antenna; as well as The receiver reports the reflection coefficients of the at least one identified antenna and each reflector to the transmitter so as to configure the reflectors of the IRS with the reflection coefficients and enable the transmitter to transmit signals via the at least one identified antenna.

10. The method according to claim 9, wherein, Estimating the channel gain includes: The receiver receives the pilot signal from at least one of the plurality of antennas of the transmitter, wherein the IRS is disabled; The receiver determines the position of the pilot signal based on the time and frequency of the pilot signal; When the IRS is disabled, the receiver estimates the channel gain based on the pilot signal; The receiver receives the pilot signal from at least one of the plurality of antennas of the transmitter, wherein the IRS is enabled and the reflection coefficient is set to one; and When the IRS is enabled, the receiver estimates the channel gain based on the pilot signal.

11. The method according to claim 9, wherein, Determining the antenna selection metric includes: The receiver estimates the first channel gain by receiving the pilot signal from at least one of the plurality of antennas of the transmitter of the wireless communication system and the IRS, wherein the reflection coefficient of each reflector of the IRS is set to zero; The receiver estimates the second channel gain by receiving the pilot signal from at least one of the plurality of antennas and the IRS, wherein the reflection coefficient of each reflector of the IRS is set to one; The receiver determines the difference between the second channel gain and the first channel gain for the at least one antenna; and The receiver identifies at least one antenna among the plurality of antennas whose sum of the magnitude of the first channel gain and the magnitude of the difference between the second channel gain and the first channel gain is the largest.

12. The method according to claim 9, wherein, Estimating the channel gain includes: The receiver listens to the estimated channel gain for the at least one antenna at various times; The receiver trains a machine learning (ML) engine to learn the estimated channel gain; and The receiver predicts the channel gain when the pilot signal is transmitted to the receiver via the at least one antenna based on learning using the ML engine.

13. The method according to claim 9, wherein, Determining the reflection coefficient of each reflector of the IRS includes: The receiver monitors the reflection coefficient determined at each moment; The receiver trains the ML engine to learn the reflection coefficients determined at various times; and The receiver predicts the reflection coefficient of each reflector of the IRS based on learning using the ML engine.

14. A method for using a smart reflective surface (IRS) to enhance the power of a signal in a wireless communication system, the method comprising: The transmitter of the wireless communication system estimates a first channel gain by transmitting pilot signals to the receiver via each of the transmitter's multiple antennas and the IRS, wherein the reflection coefficient of each reflector of the IRS is set to zero; The transmitter estimates the second channel gain by transmitting the pilot signal to the receiver via each of the plurality of antennas and the IRS, wherein the reflection coefficient of each reflector of the IRS is set to one; The transmitter determines the difference between the second channel gain and the first channel gain for each antenna; The transmitter sorts each antenna in descending order of the difference between the second channel gain and the first channel gain. The transmitter selects the first n antennas from the sorted antennas as an antenna set; The transmitter transmits the pilot signal via a selected set of antennas; The transmitter determines the reflection coefficient of each reflector of the IRS based on the antenna set; The transmitter configures the reflector of the IRS using the reflection coefficient; The transmitter determines the optimal beamforming required for transmitting a signal from the antenna set based on the reflection coefficient and the antenna set; and The transmitter transmits signals to the receiver via the configured reflector and the antenna set based on the optimal beamforming.

15. A method for using a smart reflective surface (IRS) to enhance the power of a signal in a wireless communication system, the method comprising: The receiver estimates the first channel gain by receiving pilot signals from each of the multiple antennas of the transmitter of the wireless communication system and the IRS, wherein the reflection coefficient of each reflector of the IRS is set to zero; The receiver estimates the second channel gain by receiving the pilot signals from each of the plurality of antennas and the IRS, wherein the reflection coefficient of each reflector of the IRS is set to one; The receiver determines the difference between the second channel gain and the first channel gain for each antenna; The receiver sorts each antenna in descending order of the difference between the second channel gain and the first channel gain. The receiver selects the first n antennas from the sorted antennas as an antenna set; The receiver determines the reflection coefficient of each reflector of the IRS based on the antenna set and the pilot signal transmitted by the transmitter; and The receiver reports the selected first n antennas and the reflection coefficient of each reflector to the transmitter so that the reflectors of the IRS can be configured using the reflection coefficients and the transmitter can transmit signals via the identified antennas.

16. An apparatus for using a smart reflective surface (IRS) to enhance the power of a signal in a wireless communication system, the apparatus comprising: Memory; A communicator, the communicator being equipped with at least one antenna and at least one radio frequency (RF) chain; as well as A processing circuit, connected to the memory and the communicator, is configured to perform the method according to any one of claims 1 to 15.

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