# US 8,542,635 B2 · Calibration apparatus and method for multicell multiple input multiple output transmission in multiple antenna system > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 8,542,635 B2 - Document ID: US8542635B2 - Status: Granted - Kind: B2 - Application number: 12/915,814 - Filed: 2010-10-29 - Published: 2011-05-05 - Granted: 2013-09-24 - Earliest claimed: 2009-10-30 - Assignees: Samsung Electronics Co., Ltd. - Applicants: Shuangfeng Han; Chi-Woo Lim - Inventors: Shuangfeng Han; Chi-Woo Lim - Web page: https://patentgrep.com/patent/US8542635B2 ## CPC - H04B 7/024: Co-operative use of antennas of several sites, e.g. in co-ordinated multipoint or co-operative multiple-input multiple-output [MIMO] systems - H04B 17/12: of transmit antennas, e.g. of the amplitude or phase - H04B: TRANSMISSION ## Abstract A calibration apparatus and a calibration method for multicell Multiple Input Multiple Output (MIMO) transmission in a multiple antenna system are provided. More particularly, an operating method of a Mobile Station (MS) for performing calibration for multicell MIMO transmission in a multiple antenna system includes negotiating a multi-Base Station (BS) joint processing with a BS, receiving a control message including information instructing multi-BS calibration for sounding based on the multi-BS joint processing, from the BS; when receiving the control message involving the multi-BS joint processing, generating a second sounding sequence by mapping estimated phases of downlink channels per subcarrier of BSs to a first sounding sequence allocated from the BS, and transmitting the second sounding sequence, including the phases of the downlink channels per subcarrier, over a sounding symbol interval with respect to each of the BSs involving the multi-BS joint processing. Hence, feedback overhead in the calibration of the multicell MIMO transmission can be reduced. ## Claims ### Claim 1 An operating method of a Mobile Station (MS) for performing calibration for multicell Multiple Input Multiple Output (MIMO) transmission in a multiple antenna system, the method comprising: negotiating a multi-Base Station (BS) joint processing with a BS; receiving a control message comprising information instructing multi BS calibration for sounding based on the multi BS joint processing, from the BS; when receiving the control message involving the multi-BS joint processing, generating a second sounding sequence by mapping estimated phases of downlink channels per subcarrier of BSs to a first sounding sequence allocated from the BS; and transmitting the second sounding sequence, comprising the phases of the downlink channels per subcarrier, over a sounding symbol interval with respect to each of the BSs involving the multi-BS joint processing. ### Claim 2 (depends on 1) The method of claim 1, wherein the generating of the second sounding sequence comprises: receiving allocation resource for the first sounding sequence; measuring the phases of the downlink channels per subcarrier with respect to the estimated BSs involving the multi-BS joint processing; and mapping the phases of the downlink channels to the first sounding sequence. ### Claim 3 (depends on 1) The method of claim 1, wherein the transmitting of the second sounding sequence transmits a sounding sequence comprising the phase of the downlink channel per subcarrier of a corresponding BS over a corresponding sounding interval. ### Claim 4 (depends on 3) The method of claim 3, wherein the corresponding sounding interval is a predefined calibration interval based on the sounding sequence between the BS and the MS. ### Claim 5 (depends on 1) The method of claim 1, wherein a whole sounding interval for delivering the second sounding sequence is determined by considering the number of the BSs involving the multi-BS joint processing. ### Claim 6 (depends on 1) The method of claim 1, wherein the multicell MIMO transmission is at least one of a Closed Loop Macro Diversity (CL-MD) and a Collaborative MIMO (Co-MIMO). ### Claim 7 (depends on 1) The method of claim 1, wherein the multiple antenna system comprises Time Division Duplex (TDD) system based on Orthogonal Frequency Division Multiplexing (OFDM)/Orthogonal Frequency Division Multiple Access (OFDMA). ### Claim 8 An operating method of a Base Station (BS) for performing calibration for multicell Multiple Input Multiple Output (MIMO) transmission in a multiple antenna system, the method comprising: negotiating a multi-BS joint processing with a Mobile Station (MS); transmitting a control message comprising information instructing multi BS calibration for sounding based on the multi-BS joint processing, to the MS; after transmitting the control message, receiving a sounding sequence comprising a phase of a downlink channel per subcarrier of the MS over a corresponding sounding symbol interval; and compensating for mismatch between the phase of the downlink channel and a phase of an uplink channel from the received sounding sequence. ### Claim 9 (depends on 8) The method of claim 8, wherein the multicell MIMO transmission is at least one of a Closed Loop Macro Diversity (CL-MD) and a Collaborative MIMO (Co-MIMO). ### Claim 10 (depends on 8) The method of claim 8, wherein the multiple antenna system comprises Time Division Duplex (TDD) system based on Orthogonal Frequency Division Multiplexing (OFDM)/Orthogonal Frequency Division Multiple Access (OFDMA). ### Claim 11 An apparatus of a Mobile Station (MS) for performing calibration for multicell Multiple Input Multiple Output (MIMO) transmission in a multiple antenna system, the apparatus comprising: a controller for negotiating a multi-Base Station (BS) joint processing with a BS; a receiver for receiving a control message comprising information instructing multi BS calibration for sounding based on the multi BS joint processing, from the BS; a sounding mapper for, when the control message is received, generating a second sounding sequence by mapping estimated phases of downlink channels per subcarrier of BSs involving the multi-BS joint processing, to a first sounding sequence allocated from the BS; and a transmitter for transmitting the second sounding sequence, comprising the phases of the downlink channels per subcarrier, over a sounding symbol interval with respect to each of the BSs involving the multi-BS joint processing. ### Claim 12 (depends on 11) The apparatus of claim 11, wherein the sounding mapper is allocated the first sounding sequence, measures the phase of the downlink channel per subcarrier with respect to the estimated BSs involving the multi-BS joint processing, and maps the phases of the downlink channels to the first sounding sequence. ### Claim 13 (depends on 11) The apparatus of claim 11, wherein the transmitter transmits a sounding sequence comprising the phase of the downlink channel per subcarrier of a corresponding BS over a corresponding sounding interval. ### Claim 14 (depends on 13) The apparatus of claim 13, wherein the corresponding sounding interval is a predefined calibration interval based on the sounding sequence between the BS and the MS. ### Claim 15 (depends on 11) The apparatus of claim 11, wherein a whole sounding interval for delivering the second sounding sequence is determined by considering the number of the BSs involving the multi-BS joint processing. ### Claim 16 (depends on 11) The apparatus of claim 11, wherein the multicell MIMO transmission is at least one of a Closed Loop Macro Diversity (CL-MD) and a Collaborative MIMO (Co-MIMO). ### Claim 17 (depends on 11) The apparatus of claim 11, wherein the multiple antenna system comprises Time Division Duplex (TDD) system based on Orthogonal Frequency Division Multiplexing (OFDM)/Orthogonal Frequency Division Multiple Access (OFDMA). ### Claim 18 An apparatus of a Base Station (BS) for performing calibration for multicell Multiple Input Multiple Output (MIMO) transmission in a multiple antenna system, the apparatus comprising: a controller for negotiating a multi-BS joint processing with a Mobile Station (MS); a transmitter for transmitting a control message comprising information instructing multi-BS calibration for sounding based on the multi-BS joint processing, to the MS; a receiver for, after the control message is sent, receiving a sounding sequence comprising a phase of a downlink channel per subcarrier of the MS over a corresponding sounding symbol interval; and a phase shift compensator for compensating for mismatch between the phase of the downlink channel and a phase of an uplink channel from the received sounding sequence. ### Claim 19 (depends on 18) The apparatus of claim 18, wherein the multicell MIMO transmission is at least one of a Closed Loop Macro Diversity (CL-MD) and a Collaborative MIMO (Co-MIMO). ### Claim 20 (depends on 18) The apparatus of claim 18, wherein the multiple antenna system comprises Time Division Duplex (TDD) system based on Orthogonal Frequency Division Multiplexing (OFDM)/Orthogonal Frequency Division Multiple Access (OFDMA).