# US 10,312,974 B2 · MIMO transmission scheme using multiple antennas in a radio communication station > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,312,974 B2 - Document ID: US10312974B2 - Status: Granted - Kind: B2 - Application number: 15/508,448 - Filed: 2015-09-02 - Published: 2017-10-12 - Granted: 2019-06-04 - Earliest claimed: 2014-09-03 - Assignees: Ntt Docomo, Inc. - Applicants: Ntt Docomo, Inc. - Inventors: Jiyun Shen; Satoshi Suyama; Yukihiko Okumura - Web page: https://patentgrep.com/patent/US10312974B2 ## CPC - H04B 7/0413: MIMO systems - H04B 7/043: {using best eigenmode, e.g. beam forming or beam steering} - H04B 7/0465: {taking power constraints at power amplifier or emission constraints, e.g. constant modulus, into account} - H04B 7/06: at the transmitting station - H04B 7/0617: {for beam forming} - H04B 7/10: Polarisation diversity; Directional diversity - H04L 25/03: Shaping networks in transmitter or receiver, e.g. adaptive shaping networks - H04W 16/28: using beam steering - Y02D 30/70: in wireless communication networks - H04B: TRANSMISSION - H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M) - H04W: WIRELESS COMMUNICATION NETWORKS (broadcast communication H04H; communication systems using wireless links for non-selective communication, e.g. wireless extensions H04M1/72) - Y02D: CLIMATE CHANGE MITIGATION TECHNOLOGIES IN INFORMATION AND COMMUNICATION TECHNOLOGIES [ICT], I.E. INFORMATION AND COMMUNICATION TECHNOLOGIES AIMING AT THE REDUCTION OF THEIR OWN ENERGY USE ## Abstract A radio transmitting station includes: multiple transmitting antenna elements configured to transform electrical signals into radio waves and emit the radio waves; a precoder configured to control a beam direction of the radio waves to be emitted from the multiple transmitting antenna elements by giving precoding weights to the electrical signals to be supplied to the multiple transmitting antenna elements; and at least one power adjuster configured to adjust power of an electrical signal that is to be supplied to at least a portion of the multiple transmitting antenna elements, such that differences between powers of the electrical signals to be supplied to the multiple transmitting antenna elements are reduced. ## Claims ### Claim 1 A radio transmitting station comprising: multiple transmitting antennas that transform electrical signals into radio waves and emit the radio waves; a processor that controls a beam direction of the radio waves to be emitted from the multiple transmitting antennas by giving precoding weights to the electrical signals to be supplied to the multiple transmitting antennas; and at least one power adjuster that adjusts power of an electrical signal that is to be supplied to at least a portion of the multiple transmitting antennas, such that differences between powers of the electrical signals to be supplied to the multiple transmitting antennas are reduced, wherein the processor gives the precoding weights to the electrical signals to be supplied to the multiple transmitting antennas using a precoding algorithm that is selected from precoding algorithms differing from one another, and wherein the power adjuster changes an amount of power adjustment according to the precoding algorithm used in the processor. ### Claim 2 (depends on 1) The radio transmitting station according to claim 1, wherein the power adjuster reduces power of an electrical signal that is to be supplied to a transmitting antenna that is arranged in an edge portion among the arrayed multiple transmitting antennas. ### Claim 3 (depends on 2) The radio transmitting station according to claim 2, wherein the power adjuster increases power of an electrical signal that is to be supplied to a transmitting antenna that is arranged in a center portion among the arrayed multiple transmitting antennas. ### Claim 4 (depends on 2) The radio transmitting station according to claim 2, wherein the power adjuster adjusts, by a preset amount of adjustment, the power of the electrical signal to be supplied to the at least a portion of the multiple transmitting antennas. ### Claim 5 (depends on 2) The radio transmitting station according to claim 2, further comprising a measurer that measures the power of the electrical signal to be supplied to the at least a portion of the multiple transmitting antennas, wherein the power adjuster, on the basis of the power measured by the measurer, adjusts the power of the electrical signal to be supplied to the at least a portion of the multiple transmitting antennas. ### Claim 6 (depends on 5) The radio transmitting station according to claim 5, wherein the power adjuster multiplies the power of the electrical signal to be supplied to the at least a portion of the multiple transmitting antennas by a reciprocal of a time-average of, or a reciprocal of a normalized power of, the power of the electrical signal to be supplied to the at least a portion of the multiple transmitting antennas, the power having been measured by the measurer. ### Claim 7 (depends on 2) The radio transmitting station according to claim 2, further configured to inform a radio receiving station of a result of power adjustment performed by the power adjuster. ### Claim 8 (depends on 1) The radio transmitting station according to claim 1, wherein the power adjuster increases power of an electrical signal that is to be supplied to a transmitting antenna that is arranged in a center portion among the arrayed multiple transmitting antennas. ### Claim 9 (depends on 8) The radio transmitting station according to claim 8, wherein the power adjuster adjusts, by a preset amount of adjustment, the power of the electrical signal to be supplied to the at least a portion of the multiple transmitting antennas. ### Claim 10 (depends on 8) The radio transmitting station according to claim 8, further comprising a measurer that measures the power of the electrical signal to be supplied to the at least a portion of the multiple transmitting antennas, wherein the power adjuster, on the basis of the power measured by the measurer, adjusts the power of the electrical signal to be supplied to the at least a portion of the multiple transmitting antennas. ### Claim 11 (depends on 10) The radio transmitting station according to claim 10, wherein the power adjuster multiplies the power of the electrical signal to be supplied to the at least a portion of the multiple transmitting antennas by a reciprocal of a time-average of, or a reciprocal of a normalized power of, the power of the electrical signal to be supplied to the at least a portion of the multiple transmitting antennas, the power having been measured by the measurer. ### Claim 12 (depends on 8) The radio transmitting station according to claim 8, further configured to inform a radio receiving station of a result of power adjustment performed by the power adjuster. ### Claim 13 (depends on 1) The radio transmitting station according to claim 1, wherein the power adjuster adjusts, by a preset amount of adjustment, the power of the electrical signal to be supplied to the at least a portion of the multiple transmitting antennas. ### Claim 14 (depends on 13) The radio transmitting station according to claim 13, further configured to inform a radio receiving station of a result of power adjustment performed by the power adjuster. ### Claim 15 (depends on 1) The radio transmitting station according to claim 1, further comprising a measurer that measures the power of the electrical signal to be supplied to the at least a portion of the multiple transmitting antennas, wherein the power adjuster, on the basis of the power measured by the measurer, adjusts the power of the electrical signal to be supplied to the at least a portion of the multiple transmitting antennas. ### Claim 16 (depends on 15) The radio transmitting station according to claim 15, wherein the power adjuster multiplies the power of the electrical signal to be supplied to the at least a portion of the multiple transmitting antennas by a reciprocal of a time-average of, or a reciprocal of a normalized power of, the power of the electrical signal to be supplied to the at least a portion of the multiple transmitting antennas, the power having been measured by the measurer. ### Claim 17 (depends on 16) The radio transmitting station according to claim 16, further configured to inform a radio receiving station of a result of power adjustment performed by the power adjuster. ### Claim 18 (depends on 15) The radio transmitting station according to claim 15, further configured to inform a radio receiving station of a result of power adjustment performed by the power adjuster. ### Claim 19 (depends on 1) The radio transmitting station according to claim 1, further configured to inform a radio receiving station of a result of power adjustment performed by the power adjuster.