# US 9,883,500 B2 · Method and base station for transmitting downlink signal and method and equipment for receiving downlink signal > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 9,883,500 B2 - Document ID: US9883500B2 - Status: Granted - Kind: B2 - Application number: 14/879,736 - Filed: 2015-10-09 - Published: 2016-04-07 - Granted: 2018-01-30 - Earliest claimed: 2010-08-13 - Assignees: LG Electronics Inc. - Applicants: LG Electronics Inc. - Inventors: Moonil Lee; Jaehoon Chung; Hyunsoo Ko; Seunghee Han - Web page: https://patentgrep.com/patent/US9883500B2 ## CPC - H04W 72/23: in the downlink direction of a wireless link, i.e. towards a terminal - H04L 1/0078: {Avoidance of errors by organising the transmitted data in a format specifically designed to deal with errors, e.g. location (forward error control, e.g. FEC, CRC H04L1/004; adaptive formatting H04L1/0006; mappings H04L27/00)} - H04L 5/0007: {the frequencies being orthogonal, e.g. OFDM(A) or DMT} - H04L 5/0023: {Time-frequency-space} - H04L 5/0048: {Allocation of pilot signals, i.e. of signals known to the receiver (allocation of control signalling H04L5/0053; use of control signalling H04L5/0091)} - H04L 5/0094: {Indication of how sub-channels of the path are allocated} - H04W 24/02: Arrangements for optimising operational condition - H04W 24/10: Scheduling measurement reports {; Arrangements for measurement reports} - H04W 52/30: using constraints in the total amount of available transmission power - H04W 52/325: {Power control of control or pilot channels} - H04W 72/0453: Resources in frequency domain, e.g. a carrier in FDMA - H04W 72/20: Control channels or signalling for resource management - H04W 48/08: Access restriction or access information delivery, e.g. discovery data delivery (signalling during connection H04W76/00) - H04W 48/12: using downlink control channel - H04W: WIRELESS COMMUNICATION NETWORKS (broadcast communication H04H; communication systems using wireless links for non-selective communication, e.g. wireless extensions H04M1/72) - H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M) ## Abstract A base station of the present invention configures resources in which a downlink signal is to be transmitted with zero power using resource sets defined for a specific number of antenna ports, regardless of the number of antenna ports actually configured in the base station, and transmits resource information indicating the configured resources to a user equipment. The user equipment of the present invention receives a downlink transmission from the base station, assuming that transmission power of resources corresponding to a resource set indicated by the resource information is zero. ## Claims ### Claim 1 A method for performing, by a user equipment, channel measurement, the method comprising: receiving, by the user equipment, zero power CSI-RS information indicating one or more zero power CSI-RS resources for a cell; and performing, by the user equipment, the channel measurement based on the zero power CSI-RS information, wherein the user equipment presumes that no downlink data is mapped to the one or more zero power CSI-RS resources, wherein the zero power CSI-RS information includes a bitmap having bits corresponding respectively to CSI-RS resources defined for a fixed number of antenna ports, regardless of a number of antenna ports used in the cell, among a plurality of CSI-RS resources defined according to numbers of antenna ports, and wherein the fixed number is greater than two. ### Claim 2 (depends on 1) The method of claim 1, wherein: each of the plurality of CSI-RS resources is configured with one or more subcarriers by two consecutive OFDM symbols in a resource block according to the numbers of antenna ports; and the two consecutive OFDM symbols are OFDM symbols 5 and 6, OFDM symbols 9 and 10, or OFDM symbols 12 and 13, among OFDM symbols 0 to 13 included in the resource block. ### Claim 3 (depends on 1) The method of claim 1, wherein the plurality of CSI-RS resources comprise: CSI-RS resources for two antenna ports, each of which being configured with one subcarrier by the two consecutive OFDM symbols; CSI-RS resources for four antenna ports, each of which being configured with two subcarriers by the two consecutive OFDM symbols; and CSI-RS resources for eight antenna ports, each of which being configured with four subcarriers by the two consecutive OFDM symbols. ### Claim 4 (depends on 1) The method of claim 1, wherein the zero power CSI-RS information includes a duty cycle at which the one or more zero power CSI-RS resources occur. ### Claim 5 (depends on 1) The method of claim 1, wherein the zero power CSI-RS information includes subframe information at which occurrence of the one or more zero power CSI-RS resources start. ### Claim 6 (depends on 1) The method of claim 1, further comprising: receiving, by the user equipment, non-zero power CSI-RS information indicating a non-zero power CSI-RS resource for the cell; and receiving, by the user equipment, a CSI-RS for the cell based on the non-zero power CSI-RS information, wherein the non-zero power CSI-RS information indicates the non-zero power CSI-RS resource among CSI-RS resources defined for the number of antenna ports used for transmission of the CSI-RS in the cell. ### Claim 7 A user equipment for performing channel measurement, the user equipment comprising: a receiver, and a processor configured to: control the receiver to receive zero power CSI-RS information indicating one or more zero power CSI-RS resources for a cell; perform the channel measurement based on the zero power CSI-RS information; and presume that no downlink data is mapped to the one or more zero power CSI-RS resources, wherein the zero power CSI-RS information includes a bitmap having bits corresponding respectively to CSI-RS resources defined for a fixed number of antenna ports, regardless of a number of antenna ports used in the cell, among a plurality of CSI-RS resources defined according to numbers of antenna ports, and wherein the fixed number is greater than two. ### Claim 8 (depends on 7) The user equipment of claim 7, wherein: each of the plurality of CSI-RS resources is configured with one or more subcarriers by two consecutive OFDM symbols in a resource block according to the numbers of antenna ports; and the two consecutive OFDM symbols are OFDM symbols 5 and 6, OFDM symbols 9 and 10, or OFDM symbols 12 and 13, among OFDM symbols 0 to 13 included in the resource block. ### Claim 9 (depends on 7) The user equipment of claim 7, wherein the plurality of CSI-RS resources comprise: CSI-RS resources for two antenna ports, each of which being configured with one subcarrier by the two consecutive OFDM symbols; CSI-RS resources for four antenna ports, each of which being configured with two subcarriers by the two consecutive OFDM symbols; and CSI-RS resources for eight antenna ports, each of which being configured with four subcarriers by the two consecutive OFDM symbols. ### Claim 10 (depends on 7) The user equipment of claim 7, wherein the zero power CSI-RS information includes a duty cycle at which the one or more zero power CSI-RS resources occur. ### Claim 11 (depends on 7) The user equipment of claim 7, wherein the zero power CSI-RS information includes subframe information at which occurrence of the one or more zero power CSI-RS resources start. ### Claim 12 (depends on 7) The user equipment of claim 7, wherein: the processor is further configured to: control the receiver to receive non-zero power CSI-RS information indicating a non-zero power CSI-RS resource for the cell; and control the receiver to receive a CSI-RS for the cell based on the non-zero power CSI-RS information; and the non-zero power CSI-RS information indicates the non-zero power CSI-RS resource among CSI-RS resources defined for the number of antenna ports used for transmission of the CSI-RS in the cell. ### Claim 13 A method for receiving, by a base station, a channel measurement report, the method comprising: transmitting, by the base station, zero power CSI-RS information indicating one or more zero power CSI-RS resources for a cell; and transmitting, by the base station, the one or more zero power CSI-RS resources at zero power based on the zero power CSI-RS information, wherein the zero power CSI-RS information includes a bitmap having bits corresponding respectively to CSI-RS resources defined for a fixed number of antenna ports, regardless of a number of antenna ports used in the cell, among a plurality of CSI-RS resources defined according to numbers of antenna ports, and wherein the fixed number is greater than two. ### Claim 14 (depends on 13) The method of claim 13, wherein: each of the plurality of CSI-RS resources is configured with one or more subcarriers by two consecutive OFDM symbols in a resource block according to the numbers of antenna ports; and the two consecutive OFDM symbols are OFDM symbols 5 and 6, OFDM symbols 9 and 10, or OFDM symbols 12 and 13, among OFDM symbols 0 to 13 included in the resource block. ### Claim 15 (depends on 13) The method of claim 13, further comprising: transmitting, by the base station, non-zero power CSI-RS information indicating a non-zero power CSI-RS resource for the cell; and transmitting, by the base station, a CSI-RS for the cell based on the non-zero power CSI-RS information, wherein the non-zero power CSI-RS information indicates the non-zero power CSI-RS resource among CSI-RS resources defined for the number of antenna ports used for transmission of the CSI-RS in the cell. ### Claim 16 A base station for receiving a channel measurement report, the base station comprising: a transmitter, a receiver, and a processor configured to: control the transmitter and the receiver; control the transmitter to transmit zero power CSI-RS information indicating one or more zero power CSI-RS resources for a cell; and control the transmitter to transmit the one or more zero power CSI-RS resources at zero power based on the zero power CSI-RS information, wherein the zero power CSI-RS information includes a bitmap having bits corresponding respectively to CSI-RS resources defined for a fixed number of antenna ports, regardless of a number of antenna ports used in the cell, among a plurality of CSI-RS resources defined according to numbers of antenna ports, and wherein the fixed number is greater than two. ### Claim 17 (depends on 16) The base station of claim 16, wherein: each of the plurality of CSI-RS resources is configured with one or more subcarriers by two consecutive OFDM symbols in a resource block according to the numbers of antenna ports; and the two consecutive OFDM symbols are OFDM symbols 5 and 6, OFDM symbols 9 and 10, or OFDM symbols 12 and 13, among OFDM symbols 0 to 13 included in the resource block. ### Claim 18 (depends on 16) The base station of claim 16, wherein: the processor is further configured to: control the transmitter to transmit non-zero power CSI-RS information indicating a non-zero power CSI-RS resource for the cell; and control the transmitter to transmit a CSI-RS for the cell based on the non-zero power CSI-RS information; and the non-zero power CSI-RS information indicates the non-zero power CSI-RS resource among CSI-RS resources defined for the number of antenna ports used for transmission of the CSI-RS in the cell.