# US 11,909,479 B2 · Shaping mmWave wireless channel via multi-beam design using reconfigurable intelligent surfaces > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,909,479 B2 - Document ID: US11909479B2 - Status: Granted - Kind: B2 - Application number: 17/863,720 - Filed: 2022-07-13 - Published: 2023-02-09 - Granted: 2024-02-20 - Earliest claimed: 2021-07-14 - Assignees: NEC Corporation - Applicants: NEC Laboratories America, Inc. - Inventors: Mohammad Khojastepour; Nariman Torkzaban - Web page: https://patentgrep.com/patent/US11909479B2 ## CPC - H04B 7/0617: {for beam forming} - H04B 7/04013: {Intelligent reflective surfaces} - H04B 7/10: Polarisation diversity; Directional diversity - H04B 7/15507: {Relay station based processing for cell extension or control of coverage area, (network planning with network coordinated processing with regard to cell extension H04W16/26; network topologies using dedicated repeater stations H04W84/047; terminal devices adapted for relaying to or from an other terminal H04W88/04)} - H04B 7/15528: {Control of operation parameters of a relay station to exploit the physical medium} - H04B: TRANSMISSION ## Abstract A method for shaping a mmWave wireless channel in a wireless network is presented. The method includes enabling communication between a multi-antenna transmitter and a multi-antenna receiver, positioning a reconfigurable intelligent surface (RIS) in a vicinity of the multi-antenna transmitter and the multi-antenna receiver, constructing the RIS as a uniform planar array (UPA) structure forming a multi-beamforming framework, a surface of the UPA defining an array of discrete elements arranged in a grid pattern, wherein parameters of the discrete elements of the UPA are controllable to achieve multiple disjoint beams covering different solid angles, and enabling the plurality of users of the plurality of mobile devices positioned in blind spots of a coverage map to communicate with the multi-antenna transmitter by employing the MS to generate sharp and effective beams having almost uniform gain in a desired angular coverage interval (ACI). ## Claims ### Claim 1 A method for shaping a millimeter wave (mmWave) wireless channel in a wireless network, the method comprising: receiving signals at a reconfigurable intelligent surface (RIS) in a vicinity of a multi-antenna transmitter and a multi-antenna receiver the signals communicated between the multi-antenna transmitter and the multi-antenna receiver through the reconfigurable intelligent surface (RIS), the RIS being a uniform planar array (UPA) structure forming a multi-beamforming framework, a surface of the UPA defining an array of discrete elements arranged in a grid pattern, wherein parameters of the discrete elements of the UPA are controllable to achieve multiple disjoint beams covering different solid angles, the RIS reflecting the signals received from the multi-antenna transmitter toward the multi-antenna receiver; and and enabling the plurality of users of the plurality of mobile devices positioned in blind spots of a coverage map to communicate with the multi-antenna transmitter by employing the RIS to generate sharp and effective beams having almost uniform gain in a desired angular coverage interval (ACI). ### Claim 2 (depends on 1) The method of claim 1, wherein channel matrices of each discrete element of the UPA of the RIS are given as: Ht=dMt{Ωt}ρtdMH{Ω1}, and Hr=dM{Ω2}ρrdMrH{Ωr}, where Ω1, Ω2 are solid angles of departure (AoD) of beams transmitted from the multi-antenna transmitter and the RIS, Ω1 and Ω2 are solid angles of arrival (AoA) of the beams received at the RIS and the multi-antenna receiver, respectively, a gain of the line-of-sight (LoS) paths from the transmitter to the RIS and from the RIS to the receiver are demoted by ρ1 and ρr respectively, and dMt, dM, dMH, and dMrH and denotes various directivity vectors defining distances between the discrete elements of ti UPA of the RIS. ### Claim 3 (depends on 1) The method of claim 1, wherein a beamforming vector is defined as: c = [ c 0 , 0 , … , c 0 , M h - 1 , c 1 , 0 , … , c M v - 1 , M h - 1 ] wherein values of phase shift θk and attenuation value βk for the kth elements of the RIS are found by using corresponding beamforming coefficient ck and a value of the kth element of a directivity vector dM(Ω1) for any receive incident solid an Ω1. ### Claim 4 (depends on 1) The method of claim 1, wherein the sharp and effective beams depend on solid angles at which incident waves from the multi-antenna receiver activate the discrete elements of the UPA. ### Claim 5 (depends on 1) The method of claim 1, wherein the RIS is a passive RIS where both phase control and gain control are permitted. ### Claim 6 (depends on 1) The method of claim 1, wherein values for a phase shift and an attenuation value of the MS are determined by using corresponding beamforming coefficients and a value of a kth element of a directivity vector for any receive incident solid angle. ### Claim 7 (depends on 1) The method of claim 1, wherein the multi-beamforming framework is designed as an optimization problem. ### Claim 8 A non-transitory computer-readable storage medium comprising a computer-readable program for shaping a millimeter wave (mmWave) wireless channel in a wireless network, wherein the computer-readable program when executed on a computer causes the computer to perform the steps of: receiving signals at a reconfigurable intelligent surface (RIS) in a vicinity of a multi-antenna transmitter and a multi-antenna receiver to communicate between the multi-antenna transmitter and the multi-antenna receiver through the reconfigurable intelligent surface (RIS), the RIS being a uniform planar array (UPA) structure forming a multi-beamforming framework, a surface of the UPA defining an array of discrete elements arranged in a grid pattern, wherein parameters of the discrete elements of the UPA are controllable to achieve multiple disjoint beams covering different solid angles, the RIS reflecting the signals received from the multi-antenna transmitter toward the multi-antenna receiver; and enabling the plurality of users of the plurality of mobile devices positioned in blind spots of a coverage map to communicate with the multi-antenna transmitter by employing the RIS to generate sharp and effective beams having almost uniform gain in a desired angular coverage interval (ACI). ### Claim 9 (depends on 8) The non-transitory computer-readable storage medium of claim 8, wherein channel matrices of each discrete element of the UPA of the RIS are given as: Ht=dMt{Ωt}ρtdMH{Ω1}, and Hr=dM{Ω2}ρrdMrH{Ωr}, where Ω1 and Ω2 are solid angles of departure (AoD) of beams transmitted from the multi-antenna transmitter and the RIS, Ω1 and Ωr are solid angles of arrival (AoA) of the beams received at the RIS and the multi-antenna receiver, respectively, a gain of the line-of-sight (LOS) paths from the transmitter to the RIS and from the RIS to the receiver are denoted by ρt and ρr, respectively, and dMt, dM, DMH, and dMrH denotes various direct v ty vectors defining distances between the discrete elements of the UPA of the RIS. ### Claim 10 (depends on 8) The non-transitory computer-readable storage medium of claim 8, wherein a beamforming vector is defined as: c = [ c 0 , 0 , … , c 0 , M h - 1 , c 1 , 0 , … , c M v - 1 , M h - 1 ] wherein values of phase shift θk and attenuation value βk for the kth elements of the IRIS are found by using corresponding beamforming coefficient ck and a value of the kth element of a directivity vector dM{Ω1} for any receive incident solid angle Ω1. ### Claim 11 (depends on 8) The non-transitory computer readable storage medium of claim 8, wherein the sharp and effective beams depend on solid angles at which incident waves from the multi-antenna receiver activate the discrete elements of the UPA. ### Claim 12 (depends on 8) The non-transitory computer-readable storage medium of claim 8, wherein the RIS is a passive RIS where both phase control and gain control are permitted. ### Claim 13 (depends on 8) The non-transitory computer-readable storage medium of claim 8, wherein values for a phase shift and an attenuation value of the RIS are determined by using corresponding beamforming coefficients and a value of a kth element of a directivity vector for any receive incident solid angle. ### Claim 14 (depends on 8) The non-transitory computer-readable storage medium of claim 8, wherein the multi-beamforming framework is designed as an optimization problem. ### Claim 15 A system for shaping a millimeter wave (mmWave) wireless channel in a wireless network, the system comprising: a memory; and one or more processors in communication with the memory configured to: receive signals at a reconfigurable intelligent surface (RIS) in a vicinity of a multi-antenna transmitter and a multi-antenna receiver to communicate between the multi-antenna transmitter and the multi-antenna receiver through the configurable intelligent surface (RIS), the RIS being a uniform planar array (UPA) structure forming a multi-beamforming framework, a surface of the UPA defining an array of discrete elements arranged in a grid pattern, wherein parameters of the discrete elements of the UPA are controllable to achieve multiple disjoint beams covering different solid angles, the RIS reflecting the signals received from the multi-antenna transmitter toward the multi-antenna receiver; and enable the plurality of users of the plurality of mobile devices positioned in blind spots of a coverage map to communicate with the multi-antenna transmitter by employing the RIS to generate sharp and effective beams having almost uniform gain in a desired angular coverage interval (ACI). ### Claim 16 (depends on 15) The system of claim 15, wherein channel matrices of each discrete element of the UPA of the RIS are given as: Ht=dMt{Ωt}ρtdMH{Ω1}, and Hr=dM{Ω2}ρrdMrH{Ωr}, where Ωr and Ω2 fat are solid angles of departure (AoD) of beams transmitted from the multi-antenna transmitter and the RIS, Ω1 and Ωr are solid angles of arrival (AoA) of the beams received at the RIS and the multi-antenna receiver, respectively, a gain of the line-of-sight (LoS) paths from the transmitter to the RIS and from the RIS to the receiver are denoted by ρt and ρr, respectively, and dMt, dM, dMH, and dMrH denotes various directivity vectors defining distances between the discrete elements of the UPA of the RIS. ### Claim 17 (depends on 15) The system of claim 15, wherein a beamforming vector is defined as: c = [ c 0 , 0 , … , c 0 , M h - 1 , c 1 , 0 , … , c M v - 1 , M h - 1 ] wherein values of phase shift θk and attenuation value βk for the kth elements of the RIS are found by using corresponding beamforming coefficient ck and a value of the kth element of directivity vector dM{Ω1} for any receive incident solid angle Ω1. ### Claim 18 (depends on 15) The system of claim 15, wherein the sharp and effective beams depend on solid angles at which incident waves from the multi-antenna receiver activate the discrete elements of the UPA. ### Claim 19 (depends on 15) The system of claim 15, wherein the RIS is a passive RIS where both phase control and gain control are permitted. ### Claim 20 (depends on 15) The system of claim 15, wherein values for a phase shift and an attenuation value of the RIS are determined by using corresponding beamforming coefficients and a value of a kth element of a directivity vector for any receive incident solid angle.