Search

KR-20260064486-A - RIS AND RIS CONTROL METHOD

KR20260064486AKR 20260064486 AKR20260064486 AKR 20260064486AKR-20260064486-A

Abstract

A reconfigurable intelligent surface (RIS) according to one embodiment disclosed in this document comprises: an oscillator that generates a clock; an optical module connected to a base station via an optical network; a reflective panel including a plurality of RIS elements; and a RIS controller including a counter. The RIS controller receives a synchronization signal from the optical network and a control signal from the base station, respectively, through the optical module, initializes the counter in accordance with the clock and the synchronization signal to synchronize with the base station, and when RIS beamforming information and RIS time information are obtained based on the control signal, generates RIS element control information for beam direction control corresponding to the RIS beamforming information, calculates a control time according to the RIS time information using the synchronized counter, and outputs the RIS element control information to the plurality of RIS elements at the calculated time so that the plurality of RIS elements generate a beam according to the RIS beamforming information.

Inventors

  • 최성우
  • 정희상

Assignees

  • 한국전자통신연구원

Dates

Publication Date
20260507
Application Date
20250730
Priority Date
20241030

Claims (10)

  1. In a RIS (reconfigurable intelligent surface) device, An oscillator that generates a clock; Optical module connected to a base station via an optical network; A reflective panel comprising a plurality of RIS elements; and It includes an RIS controller including a counter, and the RIS controller, Through the optical module, a synchronization signal from the optical network and a control signal from the base station are each received, and Initialize the counter in accordance with the clock and the synchronization signal to synchronize with the base station, and When RIS beamforming information and RIS time information are obtained based on the above control signal, RIS element control information for beam direction control corresponding to the RIS beamforming information is generated, and a control time point according to the RIS time information is calculated using the synchronized counter, and A RIS that outputs RIS element control information to the plurality of RIS elements at the calculated time so that the plurality of RIS elements generate a beam according to the RIS beamforming information.
  2. In claim 1, the optical network is, RIS comprising a synchronization line receiving a PPS (pulse per second) signal as the synchronization signal and a control line receiving the control signal in the form of an Ethernet packet.
  3. In claim 2, the synchronization line is, RIS that receives the PPS signal from the base station or external GNSS receiver.
  4. In claim 1, RIS that is connected to the base station in at least one of a one-to-one, STAR type, or RING type depending on the performance of the optical module and the performance of the optical network.
  5. In a RIS (reconfigurable intelligent surface) device, An oscillator that generates a clock; GNSS receiver generating a PPS signal; Optical module connected to a base station via an optical network; A reflective panel comprising a plurality of RIS elements; and It includes an RIS controller equipped with a counter, and the RIS controller, A control signal from the above base station is received through the optical network and the optical module, and Initialize the counter in accordance with the above clock and the above PPS signal to synchronize with the base station, and When RIS beamforming information and RIS time information are obtained based on the above control signal, RIS element control information for beam direction control corresponding to the RIS beamforming information is generated, and a control time point according to the RIS time information is calculated using the synchronized counter, and A RIS that outputs RIS element control information to the plurality of RIS elements at the calculated time so that the plurality of RIS elements generate a beam according to the RIS beamforming information.
  6. In claim 5, the optical module is, RIS that transmits the above PPS signal to at least one external RIS through the optical network.
  7. In claim 5, the optical network is, An RIS comprising a synchronization line that transmits a PPS (pulse per second) signal to at least one external RIS using the above synchronization signal, and a control line that receives the above control signal in the form of an Ethernet packet.
  8. In claim 5, RIS that is connected to the base station in at least one of a one-to-one, STAR type, or RING type depending on the performance of the optical module and the performance of the optical network.
  9. In a RIS (reconfigurable intelligent surface) control method, The above RIS includes an oscillator that generates a clock; an optical module connected to a base station via an optical network; a reflective panel comprising a plurality of RIS elements; and an RIS controller comprising a counter, and The operation of receiving a synchronization signal from the optical network and a control signal from the base station, respectively, through the optical module; Operation of initializing the counter in accordance with the clock and the synchronization signal to synchronize with the base station; An operation of generating RIS element control information for beam direction control corresponding to the RIS beamforming information when RIS beamforming information and RIS time information are obtained based on the above control signal; An operation to calculate a control time point according to the RIS time information using the synchronized counter; and An RIS control method comprising the operation of outputting RIS element control information to the plurality of RIS elements at the calculated time so that the plurality of RIS elements generate a beam according to the RIS beamforming information.
  10. In claim 9, the receiving operation is, An RIS control method comprising: receiving a PPS (pulse per second) signal as a synchronization signal through a synchronization line of the optical network; and receiving a control signal in the form of an Ethernet packet through a control line of the optical network.

Description

RIS and RIS Control Method The various embodiments disclosed in this document relate to RIS control technology. 5G mobile communication recommends the use of signals in the millimeter wave band above 24 GHz to support high data speeds. In addition, for 6G mobile communication, technologies using sub-THz or THz frequencies are being developed to enable even higher data speeds. However, signals at frequencies higher than millimeter waves (typically 24 GHz or higher) experience significant attenuation in the atmosphere, weakening rapidly with distance; furthermore, due to their short wavelengths, they can penetrate large obstacles with minimal reflection or diffraction. Consequently, signals at frequencies higher than millimeter waves can cause coverage holes, where signals transmitted from a base station fail to reach the terminal. These coverage holes occur in outdoor environments due to buildings and other facilities, while inside buildings, they frequently occur due to shielding materials such as walls. Recently, reconfigurable intelligent surfaces (RIS) are gaining attention as a means to expand communication coverage with low investment costs. A reconfigurable intelligent surface (RIS) or intelligent reflecting surface (IRS) refers to a reconfigurable surface composed of meta-elements that have artificial reflective properties different from the reflective properties of natural radio waves. An RIS consists of meta-elements arranged in two dimensions, and the reflection coefficients of the meta-elements constituting the surface can be controlled. For example, controlling the reflection coefficients of the meta-elements means that the phase and amplitude of the reflected wave can be changed. However, changing the amplitude of the reflected wave requires a radio signal amplifier, which results in high power consumption and makes the meta-elements complex. Therefore, passive RISs that use passive components to control only the phase are commonly used. Passive RISs have a simple structure, allowing for low-cost development, and consume less power, resulting in lower maintenance costs. The reflection coefficients of these RIS meta-elements (RIS elements) can be controlled via a control link from a base station that manages the network. The communication path (link) through which the base station controls the operation of the RIS is called the RIS control link, and RIS control information is transmitted through the RIS control link. The RIS control link can be implemented wirelessly or via a wired connection. Figure 1 shows a configuration diagram of a mobile communication system utilizing RIS according to one embodiment. Figure 2 is a diagram illustrating RIS control based on RIS control information. Figure 3 shows a conceptual diagram of a wired RIS control link connecting a base station and multiple RISs with optical cables. FIG. 4 is an example of a wired RIS control channel according to one embodiment, and FIG. 5 shows a synchronization signal according to one embodiment. FIG. 6 shows a RIS configuration diagram according to one embodiment. FIG. 7 shows a flowchart of an RIS control method according to one embodiment. FIG. 8 is a timing diagram of a signal received or generated in an RIS according to one embodiment. FIG. 9 shows a configuration diagram illustrating the connections between a base station and a plurality of RISs according to one embodiment. In relation to the description of the drawings, the same or similar reference numerals may be used for identical or similar components. The wired RIS control link receives RIS control signals directly from the base station through a wired cable (wired connection) - various optical cables, UTP cables, etc. However, wired RIS control links have disadvantages such as cable construction costs and maintenance costs because they must be connected from the base station to the RIS via wires. However, if wired infrastructure such as optical cables is available around the RIS, the wired RIS control method can be easily applied. Furthermore, the wired RIS control method has the advantage of being usable without allocating wireless transmission resources (frequency, time), even when controlling multiple RISs. In addition, wired transmission has a lower transmission error rate than wireless reception methods, resulting in higher reliability of control signals. Meanwhile, transmission rules (protocols) and interfaces must be defined for the RIS control link (hereinafter referred to as the 'control link'). For example, if the number of RIS elements is large or the phase resolution of the RIS elements is high, the reflection capability of the RIS is improved, but the amount of RIS control information also increases accordingly. As another example, the RIS beam may be set by slot and symbol spacing, or by distinguishing between uplink and downlink, in which case the number of RIS controls increases. Therefore, the RIS control link must be designed to correspond to the amo