# US 8,542,770 B2 · Radio communication device and radio communication method > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 8,542,770 B2 - Document ID: US8542770B2 - Status: Granted - Kind: B2 - Application number: 12/673,560 - Filed: 2008-08-15 - Published: 2011-09-08 - Granted: 2013-09-24 - Earliest claimed: 2007-08-17 - Assignees: Panasonic Corporation - Applicants: Seigo Nakao; Masayuki Hoshino; Atsushi Sumasu; Katsuhiko Hiramatsu - Inventors: Seigo Nakao; Masayuki Hoshino; Atsushi Sumasu; Katsuhiko Hiramatsu - Web page: https://patentgrep.com/patent/US8542770B2 ## CPC - 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)} - H04B 7/0413: MIMO systems - H04B 7/0417: Feedback systems - H04B 7/0682: {using phase diversity (e.g. phase sweeping)} - H04L 5/0023: {Time-frequency-space} - H04L 25/0226: {sounding signals per se} - H04L 25/0228: {with direct estimation from sounding signals} - H04L 27/2613: {Structure of the reference signals} - H04L 27/2626: {Arrangements specific to the transmitter only} - H04W 74/002: {Transmission of channel access control information} - H04W 88/02: Terminal devices - H04W 88/08: Access point devices - H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M) - H04B: TRANSMISSION - H04W: WIRELESS COMMUNICATION NETWORKS (broadcast communication H04H; communication systems using wireless links for non-selective communication, e.g. wireless extensions H04M1/72) ## Abstract Provided is a radio communication device which can separate propagation paths of antenna ports and improve a channel estimation accuracy even when using virtual antennas. The device includes: a mapping unit (103) which maps a data signal after modulation to a virtual antenna (0) and a virtual antenna (1); a phase inversion unit (104) which inverts the phase of S0 transmitted from an antenna port (2) in synchronization with a phase inversion unit (105) between the odd-number slot and the even-number slot; the phase inversion unit (105) which inverts the phase of R0 transmitted from the antenna port (2); a phase inversion unit (113) which inverts the phase of S1 transmitted from an antenna port (3) in synchronization with a phase inversion unit (114); and the phase inversion unit (114) which inverts the phase of R1 transmitted from an antenna port (3). ## Claims ### Claim 1 A base station apparatus comprising: a plurality of antenna ports; and a transmitter configured to transmit, via the plurality of antenna ports, first reference signals on a plurality of first resource elements, and second reference signals different from the first reference signals on a plurality of second resource elements, a number of which in a resource block is less than a number of the plurality of first resource elements in the resource block, the first reference signals being associated with mobile stations supporting base station configurations of up to four antenna ports, and the second reference signals being associated with mobile stations supporting base station configurations of up to eight antenna ports, wherein the transmitter is configured to transmit on one of the plurality of second resource elements and via a pair of the plurality of antenna ports: a first reference signal of the second reference signals, which is multiplied by “1”, via a first one of the pair of antenna ports; and a second reference signal of the second reference signals, which is multiplied by “−1”, via a second one of the pair of antenna ports. ### Claim 2 (depends on 1) The base station apparatus according to claim 1, wherein a phase of the second reference signal of the second reference signals is reversed relative to a phase of the first reference signal of the second reference signals. ### Claim 3 (depends on 1) The base station apparatus according to claim 1, wherein prior to multiplication, the first and second reference signals of the second reference signals are identical. ### Claim 4 (depends on 1) The base station apparatus according to claim 1, wherein the first reference signals are used for both downlink channel quality estimation and downlink power measurement, and the second reference signals are used for downlink channel quality estimation. ### Claim 5 (depends on 1) The base station apparatus according to claim 1, wherein a number of resource elements for the first reference signals transmitted per antenna port is greater than a number of resource elements for the second reference signals transmitted per antenna port. ### Claim 6 (depends on 1) The base station apparatus according to claim 1, wherein a number of antenna ports of the plurality of antenna ports which are configured for a mobile station corresponds to which one or both of the first reference signals and the second reference signals are used by the mobile station for channel quality estimation. ### Claim 7 (depends on 1) The base station apparatus according to claim 1, wherein, the first reference signals are associated with mobile stations supporting base station configurations of up to four antenna ports and with mobile stations supporting base station configurations of up to eight antenna ports; and the second reference signals are only associated with mobile stations supporting base station configurations of up to eight antenna ports. ### Claim 8 (depends on 1) The base station apparatus according to claim 1 wherein, the mobile stations supporting base station configuration of up to four antenna ports are configured to support LTE, and the mobile stations supporting base station configurations of up to eight antenna ports are configured to support LTE-Advanced. ### Claim 9 (depends on 6) The base station apparatus according to claim 6, wherein the number of antenna ports configured for the mobile station is 4 or less in correspondence with a case where the first reference signals are used for channel quality estimation, and the number of antenna ports configured for the mobile station is 8 in correspondence with a case where the second reference signals are used for channel quality estimation. ### Claim 10 A transmission method performed by a base station apparatus comprising: transmitting, via a plurality of antenna ports, a-first reference signals on a plurality of first resource elements and second reference signals different from the first reference signals on a plurality of a-second resource elements, a number of which in a resource block is less than a number of the plurality of first resource elements in the resource block, the first reference signals being associated with mobile stations supporting base station configurations of up to four antenna sorts and the second reference signals being associated with mobile stations supporting base station configurations of up to eight antenna ports, wherein the transmitting includes transmitting on one of the second resource elements of the plurality of second resource elements and via a pair of the plurality of antenna ports: a first one of the second reference signals, which is multiplied by “1”, via a first one of the pair of antenna ports among the plurality of antenna ports; and a second one of the second reference signals, which is multiplied by “−1”, via a second one of the pair of antenna ports among the plurality of antenna ports. ### Claim 11 (depends on 10) The transmission method according to claim 10, wherein a phase of the second one of the second reference signals is reversed relative to a phase of said first one of the second reference signals. ### Claim 12 (depends on 10) The transmission method according to claim 10, wherein the first reference signals are used for both downlink channel quality estimation and downlink power measurement, and the second reference signals are used for downlink channel quality estimation. ### Claim 13 (depends on 10) The transmission method according to claim 10, wherein a number of antenna ports of the plurality of antenna ports which are configured for a mobile station among the plurality of antenna ports, corresponds to which one or both of the first reference signals and the second reference signals are used by the mobile station for channel quality estimation. ### Claim 14 (depends on 10) The transmission method according to claim 10, wherein a number of resource elements for the first reference signals transmitted per antenna port is greater than a number of resource elements for the second reference signals transmitted per antenna port. ### Claim 15 (depends on 10) The transmission method according to claim 10, wherein, the first reference signals are associated with mobile stations supporting base station configurations of up to four antenna ports and with mobile stations supporting base station configurations of up to eight antenna ports; and the second reference signals are associated with only mobile stations supporting base station configurations of up to eight antenna ports. ### Claim 16 (depends on 10) The transmission method according to claim 10, wherein, the mobile stations supporting base station configurations of up to four antenna ports are configured to support LTE; and the mobile stations supporting base station configuration of up to eight antenna ports are configured to support LTE-Advanced. ### Claim 17 (depends on 13) The transmission method according to claim 13, wherein the number of antenna ports configured for the mobile station is 4 or less in correspondence with a case where the first reference signals are used for channel quality estimation, and the number of antenna ports configured for the mobile station is 8 in correspondence with a case where the second reference signals are used for channel quality estimation. ### Claim 18 A base station apparatus, comprising: a plurality of antenna ports; and a transmitter configured to transmit, via the plurality of antenna ports, first reference signals on a plurality of first resource elements, and second reference signals different from the first reference signals on a plurality of second resource elements, wherein a number of the plurality of second resource elements in a resource block is less than a number of the plurality of first resource elements in the resource block, the first reference signals being associated with mobile stations of a first type and the second reference signals being associated with mobile stations of a second type, wherein the transmitter is configured to transmit on a second resource element and via a pair of antenna ports of the plurality of antenna ports: a first one of the second reference signals multiplied by “1”, via a first one of the pair of antenna ports; and a second one of the second reference signals multiplied by “−1”, via a second one of the pair of antenna ports. ### Claim 19 (depends on 18) The base station of claim 18 wherein the first type of mobile stations support base station configurations of up to four antenna ports and the second type of mobile stations support base station configurations of up to eight antenna ports. ### Claim 20 (depends on 18) The base station of claim 18 wherein the first type of mobile stations are configured to support LTE and the second type of mobile stations are configured to support LTE-Advanced. ### Claim 21 (depends on 18) The base station of claim 18 wherein the base station is configured to use up to four antenna ports to transmit a first reference signal when the first reference signal is used for channel quality estimation and to use eight antenna ports to transmit a second reference signal when the second reference signal is used for channel quality estimation. ### Claim 22 (depends on 18) The base station of claim 18 wherein, prior to the multiplication of the second one of the second reference signals, the first one of the second reference signals and the second one of the second reference signals are identical.