# US 2010/0166038 A1 · Device and method of feeding back channel information > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2010/0166038 A1 - Document ID: US20100166038A1 - Status: Published application - Kind: A1 - Application number: 12/558,016 - Filed: 2009-09-11 - Published: 2010-07-01 - Earliest claimed: 2008-12-30 - Assignees: Samsung Electronics Co., Ltd. - Inventors: Hee Kwan LEE - Web page: https://patentgrep.com/patent/US20100166038A1 ## CPC - H04B 1/707: using direct sequence modulation - H04B 7/0626: {Channel coefficients, e.g. channel state information [CSI]} - H04B 7/0628: {Diversity capabilities} - H04J 13/00: Code division multiplex systems (for frequency hopping H04B1/713) - H04B 7/0636: {Feedback format} - H04B: TRANSMISSION - H04J: MULTIPLEX COMMUNICATION (transmission in general H04B; peculiar to transmission of digital information H04L5/00; systems for the simultaneous or sequential transmission of more than one television signal H04N7/08; in exchanges H04Q11/00; stereophonic systems H04S) ## Abstract Provided is a channel information feedback method for a multiple input multiple output (MIMO) communication system. A terminal may provide feedback information generated by manipulating estimates of downlink channels using a plurality of spreading sequences. A base station may processes the feedback information provided from the terminal, and recognize channel information for each downlink channel. ## Claims ### Claim 1 A method of feeding back channel information for a terminal, the method comprising: estimating downlink channels between a plurality of transmission antennas of a base station and at least one reception antenna of the terminal; generating feedback information by manipulating estimates of the downlink channels using a plurality of spreading sequences; and providing the generated feedback information to the base station. ### Claim 2 (depends on 1) The method of claim 1, wherein the generating of the feedback information comprises: generating downlink channel information corresponding to each of the plurality of transmission antennas and the at least one reception antenna by manipulating the estimates of the downlink channels; and generating the feedback information based on the downlink channel information. ### Claim 3 (depends on 1) The method of claim 1, wherein the generating of the feedback information comprises generating the feedback information without using a quantized vector space. ### Claim 4 (depends on 2) The method of claim 2, wherein the generating of the feedback information based on the downlink channel information comprises generating the feedback information through summation of the downlink channel information corresponding to each of the plurality of transmission antennas and the at least one reception antenna. ### Claim 5 (depends on 1) The method of claim 1, wherein the plurality of spreading sequences are orthogonal with each other. ### Claim 6 (depends on 1) The method of claim 1, wherein the plurality of spreading sequences corresponds to the plurality of transmission antennas, respectively, or to a plurality of terminals, respectively. ### Claim 7 (depends on 1) The method of claim 1, wherein the providing of the generated feedback information comprises providing the generated feedback information using the same time resource or the same frequency resource as that of at least one adjacent terminal. ### Claim 8 (depends on 1) The method of claim 1, wherein the terminal is selected by the base station according to at least one predetermined user selection algorithm. ### Claim 9 A method of feeding back channel information, the method comprising: estimating downlink channels between a plurality of transmission antennas of a base station and at least one reception antenna of a terminal; selecting one of an analog feedback scheme and a digital feedback scheme; and providing, to the base station, feedback information or index information of a vector of the downlink channels, according to the selected scheme, wherein the feedback information is generated by manipulating estimates of the downlink channels using a plurality of spreading sequences in the analog feedback scheme, and the index information is determined based on the estimates of the downlink channels in a quantized vector space in the digital feedback scheme. ### Claim 10 (depends on 9) The method of claim 9, wherein the selecting comprises selecting a scheme according to a request of the base station, or according to an active selection performed by the terminal. ### Claim 11 (depends on 9) The method of claim 9, wherein the terminal generates downlink channel information corresponding to each of the plurality of transmission antennas and the at least one reception antenna by manipulating the estimates of the downlink channels in the analog feedback scheme, and generates the feedback information based on the downlink channel information. ### Claim 12 A method of recognizing channel information with respect to downlink channels between a plurality of transmission antennas of a base station and at least one reception antenna of each of at least one terminal, the method comprising: receiving feedback information provided by the at least one terminal; extracting channel information corresponding to each of the plurality of transmission antennas by processing the received feedback information using a plurality of spreading sequences; and recognizing the channel information with respect to the downlink channels based on the channel information corresponding to each of the plurality of transmission antennas. ### Claim 13 (depends on 12) The method of claim 12, further comprising: selecting the at least one terminal from among a plurality of terminals using at least one predetermined user selection algorithm. ### Claim 14 (depends on 12) The method of claim 12, wherein each of the plurality of spreading sequences corresponds to each of the plurality of transmission antennas or to each of the at least one terminal, and the at least one terminal generates the feedback information using the plurality of spreading sequences. ### Claim 15 (depends on 12) The method of claim 12, wherein the receiving of the feedback information comprises receiving the feedback information from the at least one terminal using the same time resource or the same frequency resource. ### Claim 16 (depends on 12) The method of claim 12, wherein the extracting of the channel information comprises extracting the channel information corresponding to each of the plurality of transmission antennas based on correlation values between the received feedback information and the plurality of spreading sequences. ### Claim 17 (depends on 12) The method of claim 12, wherein the recognizing of the channel information comprises recognizing the channel information with respect to the downlink channels using a minimum mean squared error (MMSE) filter. ### Claim 18 (depends on 12) The method of claim 12, further comprising: estimating uplink channels between the plurality of transmission antennas and the at least one reception antenna. ### Claim 19 A computer readable storage medium storing a program to feeding back channel information, comprising instructions to cause a computer to: estimate downlink channels between a plurality of transmission antennas of a base station and at least one reception antenna of a terminal; generate feedback information by manipulating estimates of the downlink channels using a plurality of spreading sequences; and provide the generated feedback information to the base station ### Claim 20 A terminal comprising: a channel estimator to estimate downlink channels between a plurality transmission antennas of a base station and at least one reception antenna of the terminal; a feedback information generator to generate feedback information by manipulating estimates of the downlink channels using a plurality of spreading sequences; and a feedback information provider to provide the generated feedback information to the base station. ### Claim 21 (depends on 20) The terminal of claim 20, wherein the feedback information generator generates the feedback information using the plurality of spreading sequences without using a quantized vector space. ### Claim 22 (depends on 20) The terminal of claim 20, wherein the feedback information generator generates downlink channel information corresponding to each of the plurality of transmission antennas and the at least one reception antenna by manipulating the estimates of the downlink channels. ### Claim 23 (depends on 20) The terminal of claim 20, wherein the feedback information provider provides the generated feedback information by using the same time resource or the same frequency resource as that of at least one adjacent terminal. ### Claim 24 (depends on 20) The terminal of claim 20, further comprising: an index information generator to generate index information of a vector of the downlink channels based on the estimates of the downlink channels in the quantized vector space. ### Claim 25 (depends on 24) The terminal of claim 24, wherein the feedback information provider provides the index information to the base station. ### Claim 26 A base station recognizing channel information with respect to downlink channels between a plurality of transmission antennas of the base station and at least one reception antenna of each of at least one terminal, the base station comprising: a feedback information receiver to receive feedback information fed back from the at least one terminal; an antenna-channel information extractor to extract channel information corresponding to each of the plurality of transmission antennas by processing the received feedback information using a plurality of spreading sequences; and a channel information recognizer to recognize the channel information with respect to the downlink channels based on the channel information corresponding to each of the plurality of transmission antennas. ### Claim 27 (depends on 26) The base station of claim 26, wherein the antenna-channel information extractor extracts the channel information corresponding to each of the plurality of transmission antennas based on correlation values between the received feedback information and the plurality of spreading sequences.