# US 2013/0157709 A1 · Downlink power control method and apparatus of ofdm system > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2013/0157709 A1 - Document ID: US20130157709A1 - Status: Published application - Kind: A1 - Application number: 13/721,780 - Filed: 2012-12-20 - Published: 2013-06-20 - Earliest claimed: 2011-12-20 - Assignees: Samsung Electronics Co., Ltd. - Inventors: Hyoungju JI; Younsun KIM; Joonyoung CHO; Seunghoon CHOI; Kiil KIM; Hyojin LEE - Web page: https://patentgrep.com/patent/US20130157709A1 ## CPC - H04W 52/04: Transmission power control [TPC] - H04W 52/143: {Downlink power control} - H04W 52/243: {taking into account interferences} - H04W 52/38: TPC being performed in particular situations - H04W: WIRELESS COMMUNICATION NETWORKS (broadcast communication H04H; communication systems using wireless links for non-selective communication, e.g. wireless extensions H04M1/72) ## Abstract A downlink power control method and apparatus for improving downlink power efficiency gain in an Orthogonal Frequency Division Multiplexing (OFDM) system is provided. The downlink power control method includes transmitting a downlink data channel at a normal subframe according to first downlink power information for the normal subframe, and transmitting the downlink data channel at an Almost Blank Subframe (ABS) according to second downlink power information for the ABS, wherein the first downlink power information for the normal subframe and the second downlink power information for the ABS differ from each other. The downlink power control method and apparatus is capable of regulating inter-cell interference variation between contiguous symbols at a predetermined level in a subframe at a terminal of a neighbor cell and making it possible to schedule the UE receiving the low power data channel using the power ratio of the feedbacks from the UE. ## Claims ### Claim 1 A downlink power control method of a base station, the method comprising: transmitting a downlink data channel at a normal subframe according to first downlink power information for the normal subframe; and transmitting the downlink data channel at an Almost Blank Subframe (ABS) according to second downlink power information for the ABS, wherein the first downlink power information for the normal subframe and the second downlink power information for the ABS differ from each other. ### Claim 2 (depends on 1) The downlink power control method of claim 1, wherein the transmitting of the downlink data channel at the normal subframe comprises allocating different transmit powers for symbols carrying Common Reference Signal (CRS) and symbols carrying no CRS in the normal subframe according to a predetermined ratio, and wherein the transmitting of the downlink data channel at the ABS comprises allocating a same transmit power for symbols carrying CRS and symbols carrying no CRS in the ABS. ### Claim 3 (depends on 1) The downlink power control method of claim 1, wherein the transmitting of the downlink data channel at the ABS comprises skipping a mapping of the downlink data channel to symbols carrying Common Reference Signal (CRS) in the ABS. ### Claim 4 (depends on 1) The downlink power control method of claim 1, further comprising: configuring the first downlink power information for the normal subframe and the second downlink power information for the ABS; and transmitting the first downlink power information for the normal subframe and the second downlink power information for the ABS to a terminal. ### Claim 5 A base station for controlling downlink power, the base station comprising: a transmitter for transmitting a downlink data channel at a normal subframe according to first downlink power information for the normal subframe and for transmitting a downlink data channel at an almost Blank Subframe (ABS) according to second downlink power information for the ABS, wherein the first downlink power information for the normal subframe and the second downlink power information for the ABS differ from each other. ### Claim 6 (depends on 6) The base station of claim 6, wherein the transmitter allocates different transmit powers for symbols carrying Common Reference Signal (CRS) and symbols carrying no CRS in the normal subframe according to a predetermined ratio and a same transmit power for symbols carrying CRS and symbols carrying no CRS in the ABS. ### Claim 7 (depends on 5) The base station of claim 5, further comprising: a controller for controlling the transmitter to skip a mapping of the downlink data channel to symbols carrying Common Reference Signal (CRS) in the ABS. ### Claim 8 (depends on 5) The base station of claim 5, further comprising: a controller for configuring the first downlink power information for the normal subframe and the second downlink power information for the ABS, wherein the transmitter transmits the first downlink power information for the normal subframe and the second downlink power information for the ABS to a terminal. ### Claim 9 A downlink reception method of a terminal, the method comprising: receiving a downlink data channel at a normal subframe according to first downlink power information for the normal subframe; and receiving the downlink data channel at an Almost Blank Subframe (ABS) according to second downlink power information for the ABS, wherein the first downlink power information for the normal subframe and the second downlink power information for the ABS differ from each other. ### Claim 10 (depends on 9) The downlink reception method of claim 9, wherein the receiving of the downlink data channel at the normal subframe comprises applying different transmit powers to receive symbols carrying Common Reference Signal (CRS) and symbols carrying no CRS in the normal subframe according to a predetermined ratio, and wherein the receiving of the downlink data channel at the ABS comprises applying a same transmit power to receive symbols carrying CRS and symbols carrying no CRS in the ABS. ### Claim 11 (depends on 9) The downlink reception method of claim 9, further comprising: receiving the first downlink power information for the normal subframe and the second downlink power information for the ABS; and receiving the downlink data channel in the normal subframe and the ABS according to the first downlink power information and the second downlink power information. ### Claim 12 A terminal for receiving downlink data channel, the terminal comprising: a receiver for receiving a downlink data channel at a normal subframe according to first downlink power information for a normal subframe and for receiving a downlink data channel at an Almost Blank Subframe (ABS) according to second downlink power information for ABS, wherein the first downlink power information for the normal subframe and the second downlink power information for the ABS differ from each other. ### Claim 13 (depends on 12) The terminal of claim 12, wherein the receiver applies different transmit powers to receive symbols carrying Common Reference Signal (CRS) and symbols carrying no CRS in the normal subframe according to a predetermined ratio and applies a same transmit power to receive symbols carrying CRS and symbols carrying no CRS in the ABS. ### Claim 14 (depends on 12) The terminal of claim 12, wherein the receiver receives the first downlink power information for the normal subframe and the second downlink power information for the ABS and receives the downlink data channel in the normal subframe and ABS according to the first downlink power information and the second downlink power information.