Grid of beam-type design and implementation of a reconfigurable intelligent surface

A reconfigurable intelligent surface comprising:

• a tunable reflective array comprising a plurality of reflective elements and a plurality of tunable load impedance circuits electrically connected to the plurality of reflective elements for affecting phases of electromagnetic waves reflected by the plurality of reflective elements;
• and
• an apparatus comprising:
• at least one processor, and
• at least one memory for storing instructions to be executed by the processor, wherein the at least one memory and the instructions are configured to, with the at least one processor, cause the apparatus at least to perform:
• maintaining, in said at least one memory, information on a reference incidence direction and reference configuration information defining a plurality of configurations of a plurality of tunable load impedance circuits of a tunable reflective array of a reconfigurable intelligent surface or a subpanel thereof for implementing a plurality of different reflection beams when reception occurs from the reference incidence direction;
• maintaining, in said at least one memory, a plurality of beam codebooks defining a plurality of sets of beamforming coefficients for the tunable reflective array, wherein the plurality of sets of beamforming coefficients define at least phases inducible by the plurality of tunable load impedance circuits for implementing the plurality of different reflection beams;
• measuring an incidence direction from which electromagnetic waves are received by the reconfigurable intelligent surface;
• calculating, based on the reference incidence direction, the measured incidence direction and the reference configuration information, corrected configuration information, which defines a plurality of corrected configurations of the plurality of tunable load impedance circuits for implementing the plurality of different reflection beams when reception occurs from the measured incidence direction, by calculating a correction matrix based on the reference incidence direction and the measured incidence direction, wherein the correction matrix defines a plurality of correction coefficients for the plurality of sets of beamforming coefficients, and by calculating the plurality of corrected configurations of the plurality of tunable load impedance circuits based on the plurality of beam codebooks and the correction matrix;
• and
• configuring the plurality of tunable load impedance circuits according to a corrected configuration defined in the corrected configuration information.

A system comprising:

• a reconfigurable intelligent surface and an access node,
• the reconfigurable intelligent surface comprising a tunable reflective array, a radio receiver or transceiver for reception of one or more control signals from one or more access nodes via a control channel, and an apparatus, wherein the tunable reflective array comprise a plurality of reflective elements and a plurality of tunable load impedance circuits electrically connected to the plurality of reflective elements for affecting phases of electromagnetic waves reflected by the plurality of reflective elements;
• and wherein the apparatus comprises at least one processor, and at least one memory for storing instructions to be executed by the processor, wherein the at least one memory and the instructions are configured to, with the at least one processor, cause the apparatus at least to perform:
• maintaining, in said at least one memory, information on a reference incidence direction and reference configuration information defining a plurality of configurations of a plurality of tunable load impedance circuits of a tunable reflective array of a reconfigurable intelligent surface or a subpanel thereof for implementing a plurality of different reflection beams when reception occurs from the reference incidence direction;
• maintaining, in said at least one memory, a plurality of beam codebooks defining a plurality of sets of beamforming coefficients for the tunable reflective array, wherein the plurality of sets of beamforming coefficients define at least phases inducible by the plurality of tunable load impedance circuits for implementing the plurality of different reflection beams;
• measuring an incidence direction from which electromagnetic waves are received by the reconfigurable intelligent surface;
• calculating, based on the reference incidence direction, the measured incidence direction and the reference configuration information, corrected configuration information, which defines a plurality of corrected configurations of the plurality of tunable load impedance circuits for implementing the plurality of different reflection beams when reception occurs from the measured incidence direction, by calculating a correction matrix based on the reference incidence direction and the measured incidence direction, wherein the correction matrix defines a plurality of correction coefficients for the plurality of sets of beamforming coefficients, and by calculating the plurality of corrected configurations of the plurality of tunable load impedance circuits based on the plurality of beam codebooks and the correction matrix;
• and
• configuring the plurality of tunable load impedance circuits according to a corrected configuration defined in the corrected configuration information;
• the access node comprising at least one processor, and at least one memory for storing instructions to be executed by the processor, wherein the at least one memory and the instructions are configured to, with the at least one processor, cause the access node at least to transmit one or more control signals to the reconfigurable intelligent surface via a control channel.

A method comprising:

• maintaining, in at least one memory, information on a reference incidence direction and reference configuration information defining a plurality of configurations of a plurality of tunable load impedance circuits of a tunable reflective array of a reconfigurable intelligent surface or a subpanel thereof for implementing a plurality of different reflection beams when reception occurs from the reference incidence direction;
• maintaining, in said at least one memory, a plurality of beam codebooks defining a plurality of sets of beamforming coefficients for the tunable reflective array, wherein the plurality of sets of beamforming coefficients define at least phases inducible by the plurality of tunable load impedance circuits for implementing the plurality of different reflection beams;
• measuring an incidence direction from which electromagnetic waves are received by the reconfigurable intelligent surface;
• calculating, based on the reference incidence direction, the measured incidence direction and the reference configuration information, corrected configuration information, which defines a plurality of corrected configurations of the plurality of tunable load impedance circuits for implementing the plurality of different reflection beams when reception occurs from the measured incidence direction, by calculating a correction matrix based on the reference incidence direction and the measured incidence direction, wherein the correction matrix defines a plurality of correction coefficients for the plurality of sets of beamforming coefficients, and by calculating the plurality of corrected configurations of the plurality of tunable load impedance circuits based on the plurality of beam codebooks and the correction matrix;
• and
• configuring the plurality of tunable load impedance circuits according to a corrected configuration defined in the corrected configuration information.

A computer program product, embodied on a non-transitory computer readable medium, comprising program instructions, that when run is adapted to perform:

• maintaining, in at least one memory, information on a reference incidence direction and reference configuration information defining a plurality of configurations of a plurality of tunable load impedance circuits of a tunable reflective array of a reconfigurable intelligent surface or a subpanel thereof for implementing a plurality of different reflection beams when reception occurs from the reference incidence direction;
• maintaining, in said at least one memory, a plurality of beam codebooks defining a plurality of sets of beamforming coefficients for the tunable reflective array, wherein the plurality of sets of beamforming coefficients define at least phases inducible by the plurality of tunable load impedance circuits for implementing the plurality of different reflection beams;
• measuring an incidence direction from which electromagnetic waves are received by the reconfigurable intelligent surface;
• calculating, based on the reference incidence direction, the measured incidence direction and the reference configuration information, corrected configuration information, which defines a plurality of corrected configurations of the plurality of tunable load impedance circuits for implementing the plurality of different reflection beams when reception occurs from the measured incidence direction, by calculating a correction matrix based on the reference incidence direction and the measured incidence direction, wherein the correction matrix defines a plurality of correction coefficients for the plurality of sets of beamforming coefficients, and by calculating the plurality of corrected configurations of the plurality of tunable load impedance circuits based on the plurality of beam codebooks and the correction matrix;
• and
• configuring the plurality of tunable load impedance circuits according to a corrected configuration defined in the corrected configuration information.