WE CLAIM:
1. A transmission device comprising:
an identifier to identify an interfering terminal that is a possible terminal to perform communication interfering 5 with communication with a target terminal that is a destination terminal of a data signal; and
a transmitter to set a group ID for reference signal generation to a group formed by the interfering terminal and the target terminal, and to transmit the group ID and 10 information on each terminal belonging to the group to the target terminal.
2. The transmission device according to claim 1, wherein
the identifier identifies the interfering terminal based on
15 positional information of the target terminal and positional information of another terminal.
3. The transmission device according to claim 1, wherein
the identifier identifies the interfering terminal based on
20 information on a beam with maximum power received by the target terminal and information on a beam with maximum power received by another terminal.
4. The transmission device according to claim 1, wherein
25 the identifier identifies the interfering terminal based on
spatial correlation between the target terminal and another terminal.
5. The transmission device according to claim 1, wherein
30 the identifier determines that all terminals to which
signal transmission is performed simultaneously with signal transmission to the target terminal are the interfering terminals.
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6. The transmission device according to any one of claims
1 to 5, wherein the transmitter transmits the number of
terminals that configure the group to the target terminal.
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7. The transmission device according to any one of claims
1 to 6, wherein the transmitter transmits information on a
first reference signal and information on a second
reference signal to the target terminal, the first
10 reference signal being a reference signal used by the
target terminal in demodulation of the data signal, the second reference signal being a reference signal used by the interfering terminal in demodulation of a signal directed to the interfering terminal.
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8. The transmission device according to any one of claims
1 to 6, wherein
each of the terminals retains information on candidates of the reference signals assigned to the 20 terminals configuring one of the groups, and
the transmitter transmits information on a reference signal used by the target terminal in demodulation of the data signal.
25 9. The transmission device according to claim 8, wherein each of the terminals retains a port mapping table in which a port number indicating a reference signal used by the terminal in demodulation of the data signal, the information on the candidate, and an index associated with 30 the port number and the information on the candidate are registered, and
the transmitter transmits the index to the target terminal to notify the target terminal of a reference
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signal used in demodulation of the data signal.
10. The transmission device according to claim 8 or 9,
further comprising a precoder to perform linear precoding
5 or nonlinear precoding for a transmission signal to the terminal, wherein
when the precoder performs nonlinear precoding and a reference signal is transmitted, the transmitter transmits information on the reference signal used by the target 10 terminal in demodulation of the data signal and information on the reference signal used by the interfering terminal in demodulation of the data signal to the target terminal.
11. The transmission device according to any one of claims
15 1 to 10, wherein, when communication with the target
terminal in one group is subjected to interference from communication with a terminal belonging to another group that is different from the one group,
the transmitter transmits information on a reference 20 signal used in demodulation of the data signal by the terminal that belongs to the another group, which interferes with communication with the target terminal, to the target terminal.
25 12. A receiving device to receive the data signal
transmitted by the transmission device according to claim 7 in the target terminal, the receiving device comprising
a demodulator to demodulate the data signal based on the information on the first reference signal and to cancel
30 an interference component included in the data signal based on the information on the second reference signal.
13. A base station comprising the transmission device
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according to any one of claims 1 to 11.
14. A terminal comprising the receiving device according
to claim 12.
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15. A transmission method performed by a transmission
device that transmits a data signal, the transmission
method comprising:
a step of identifying an interfering terminal that is 10 a possible terminal to perform communication interfering with communication with a target terminal that is a destination terminal of the data signal; and
a step of setting a group ID for reference signal generation to a group formed by the interfering terminal 15 and the target terminal, and transmitting the group ID and information on each terminal belonging to the group to the target terminal.
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