KR-20260067214-A - RIS-added Multi-Input Multi-Output System and Method for Channel Estimation and Beamforming

Abstract

A beamforming method for a wireless communication system comprising a base station, an intelligent reflective surface, and a plurality of user terminals according to a disclosed embodiment comprises: acquiring channel information between the base station and the intelligent reflective surface; determining a phase change value input to the intelligent reflective surface; and estimating a dependent channel based on the channel information, the phase change value, and the L-th column vector of an effective channel collected from the user terminals.

Inventors

• 홍송남
• 이정재

Assignees

• 한양대학교 산학협력단

Dates

Publication Date

20260512

Application Date

20241105

Claims (8)

1. A beamforming method of a wireless communication system comprising a base station, an intelligent reflective surface, and a plurality of user terminals, Acquire channel information between the base station and the intelligent reflective surface; Determining the phase change value input to the above intelligent reflective surface; A beamforming method for a wireless communication system comprising: estimating a dependent channel based on the channel information, the phase change value, and the L-th column vector of an effective channel collected from the user terminal.
2. In Article 1, A beamforming method for a wireless communication system further comprising performing a Kronecker product based on a preset constant value and the phase change value.
3. In Paragraph 2, Estimating the above dependent channel is, Calculate diagonal matrix values based on the L-th column vector of the above valid channel, and A beamforming method for a wireless communication system comprising: calculating the effective channels of the plurality of user terminals based on the diagonal matrix values and the channel information.
4. In Paragraph 3, A beamforming method of a wireless communication system further comprising performing hybrid beamforming based on the estimated dependent channel above.
5. Intelligent reflective surface; The above intelligent reflective surface and a base station for transmitting and receiving signals; It includes a plurality of user terminals that transmit and receive signals to and from the intelligent reflective surface; The above base station is, Acquire channel information between the above base station and the intelligent reflective surface, and Determining the phase change value input to the above intelligent reflective surface, and A wireless communication system that estimates a dependent channel based on the first channel information, the phase change value, and the L-th column vector of the effective channel collected from the user terminal.
6. In Paragraph 5, The above base station is A wireless communication system that performs a Kronecker product based on a preset constant value and the phase change value.
7. In Paragraph 6, The above base station is, Calculate diagonal matrix values based on the L-th column vector of the above valid channel, and A wireless communication system that calculates the effective channels of the plurality of user terminals based on the above diagonal matrix values and the above channel information.
8. In Article 7, The above base station is, A wireless communication system that performs hybrid beamforming based on the above-mentioned estimated dependent channel.

Description

RIS-added Multi-Input Multi-Output System and Method for Channel Estimation and Beamforming The disclosed embodiment relates to a multiple input/output system comprising a reconfigurable intelligent surface (RIS) that estimates a low-rank-based dependent wireless channel and performs hybrid beamforming suitable therefor. Wireless communication systems are widely deployed to provide various telecommunication services, such as telephony, video, data, messaging, broadcast, or other similar types of devices. These wireless communication systems may employ multiple-access technologies that support communication with such users by sharing available system resources with multiple users (e.g., bandwidth, transmission power, or other resources). Multiple-access technologies may rely on any of several examples, such as code division, time division, frequency division orthogonal frequency division, single-carrier frequency division, or time division synchronous code division. These and other multiple-access technologies have been adopted in various communication standards to provide common protocols that enable different wireless devices to communicate at city, national, regional, and even global levels. Although wireless communication systems have achieved technological advancements over the years, challenges still remain to be addressed. For example, complex and dynamic environments still attenuate or block signals between wireless transmitters and receivers. To address this, research into various channel estimation and reporting mechanisms is necessary. Among these, hybrid beamforming technology used to manage and optimize the use of finite wireless channel resources has been studied; however, there was a limitation in that it was practically impossible to secure dependent wireless channel information suitable for 6G communication. Here, the channel that needs to be estimated with the help of intelligent reflective surfaces is called a dependent channel, and a new type of multiple-input multiple-output channel distinct from conventional multiple-input multiple-output channels was required. Conventionally, channel estimation was performed efficiently by utilizing a compressed sensing algorithm based on the sparsity of dependent channels, and a technology for hybrid beamforming optimization suitable for this was proposed. However, as the size of wireless communication systems continues to grow and existing channel estimation methods fail to deliver good performance for 6G communication, the need for new technology is emerging. Meanwhile, in order to secure a higher data transmission rate than 5G communication, 6G communication requires increasing the frequency and bandwidth. Since radio waves in high frequency bands have strong directional properties, there was a problem where the waves were not transmitted well to the receiver when there were intermediate obstacles. FIG. 1 is a drawing for explaining an example of a wireless communication system according to a disclosed embodiment. FIG. 2 is a block diagram of a base station and a user terminal according to a disclosed embodiment. FIG. 3 is a flowchart for explaining a disclosed beamforming method. FIG. 4 is a diagram illustrating an embodiment of a disclosed wireless communication system that reduces training overhead and computational complexity. Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the attached drawings. However, the technical concept of the present invention is not limited to the embodiments described herein and may be embodied in other forms. Rather, the embodiments introduced herein are provided to ensure that the disclosed content is thorough and complete and to sufficiently convey the concept of the present invention to those skilled in the art. In this specification, when a component is described as being on another component, it means that it may be formed directly on the other component or that a third component may be interposed between them. Additionally, in the drawings, shapes and sizes are exaggerated for the effective illustration of the technical content. Additionally, although terms such as first, second, third, etc., have been used to describe various components in the various embodiments of this specification, these components should not be limited by such terms. These terms are used merely to distinguish one component from another. Accordingly, what is referred to as the first component in one embodiment may be referred to as the second component in another embodiment. Each embodiment described and illustrated herein also includes its complementary embodiment. Furthermore, in this specification, "and/or" is used to mean including at least one of the components listed before and after it. In the specification, singular expressions include plural expressions unless the context clearly indicates otherwise. Furthermore, terms such as "include" or "have" are intended to specify the