CLAIMS
1. A transmitting apparatus comprising:
a plurality of transmission antennas capable of forming a plurality of beams respectively directed to a plurality of receiving apparatuses; and
a precoder to perform precoding on signals transmitted from the transmission antennas such that received power in third receiving apparatuses, which are the receiving apparatuses excluding a first receiving apparatus serving as a transmission destination of a transmission signal among the receiving apparatuses and a second receiving apparatus, which is one of the receiving apparatuses, is equal to or smaller than a threshold.
2. The transmitting apparatus according to claim 1, wherein received power in the second receiving apparatuses is larger than the threshold.
3. The transmitting apparatus according to claim 1 or 2, wherein signals transmitted from the transmission antennas are multiplied with a first matrix, which is a precoding matrix for reducing the received power in the third receiving apparatuses to the threshold or less, and a multiplication result is multiplied with a second matrix, which is a precoding matrix for forming a beam directed to the first receiving apparatus.
4. The transmitting apparatus according to claim 1, 2, or 3, wherein the second receiving apparatus corresponding to the first receiving apparatus is selected on the basis of a correlation between a transmission line matrix between the first receiving apparatus and the transmitting apparatus and transmission line matrixes between the receiving

apparatuses other than the first receiving apparatus and the transmitting apparatus.
5. The transmitting apparatus according to claim 1, 2, or 3, wherein the second receiving apparatus corresponding to the first receiving apparatus is selected on the basis of geographical separation degrees between the first receiving apparatus and the receiving apparatuses other than the first receiving apparatus.
6. The transmitting apparatus according to any one of claims 1 to 5, further comprising an ordering unit to determine order of the receiving apparatuses in the precoding.
7. The transmitting apparatus according to claim 6, wherein
the ordering unit carries out power distribution to the receiving apparatuses, and
the precoder multiplies signals transmitted from the transmission antennas with a power distribution matrix corresponding to a result of the power distribution and a precoding matrix for carrying out the precoding.
8. The transmitting apparatus according to claim 6, wherein the order is order decided such that the receiving apparatus next to the first receiving apparatus in order is the second receiving apparatus corresponding to the first receiving apparatus.
9. The transmitting apparatus according to claim 8, wherein the ordering unit performs the ordering such that the receiving apparatuses continuous in order are

geographically close to or separated from each other.
10. The transmitting apparatus according to claim 8 or 9,
further comprising an interference removing unit to perform
sequential interference removal, wherein
a precoding matrix for setting the receiving apparatus last in order among the receiving apparatuses ordered by the ordering unit as the first receiving apparatus is a matrix for performing the precoding such that received power in fourth receiving apparatuses, which are the receiving apparatuses excluding the first receiving apparatus, is equal to or smaller than the threshold and a precoding matrix for setting the receiving apparatus other than the receiving apparatus last in order among the receiving apparatuses as the first receiving apparatus is a matrix for performing the precoding such that received power in the third receiving apparatuses is equal to or smaller than the threshold, and
the interference removing unit sequentially carries out, as the sequential interference removal, processing for sequentially removing interference that occurs in the receiving apparatuses next in order excluding interference removal processing corresponding to the receiving apparatus in a first place, which is a next place of a last place.
11. The transmitting apparatus according to claim 6 or 7, wherein the ordering unit sets the order to descending order of non-negative eigenvalues or non-negative singular values of transmission line matrixes between the transmitting apparatus and the receiving apparatuses.
12. The transmitting apparatus according to claim 6 or 7, wherein the ordering unit sets the order to ascending order

of non-negative eigenvalues or non-negative singular values of transmission line matrixes between the transmitting apparatus and the receiving apparatuses.
13. A receiving apparatus that receives signals transmitted from the transmitting apparatus according to any one of claims 1 to 12, the receiving apparatus comprising a decoder to extract a desired signal from the signals received from the transmitting apparatus.
14. A control station in a communication system capable of forming a plurality of beams respectively directed to a plurality of receiving apparatuses by a plurality of transmission antennas mounted on a plurality of transmitting apparatuses, the control station comprising:
a precoder calculation unit to calculate a precoding matrix for performing precoding such that received power in third receiving apparatuses, which are the receiving apparatuses excluding a first receiving apparatus serving as a transmission destination of a transmission signal among the receiving apparatuses and a second receiving apparatus, which is one of the receiving apparatuses, is equal to or smaller than a threshold, and
a transceiver to transmit the precoding matrix to the transmitting apparatuses.
15. A transmission precoding method in a transmitting
apparatus including a plurality of transmission antennas
capable of forming a plurality of beams respectively
directed to a plurality of receiving apparatuses, the
transmission precoding method comprising:
a first step of determining a first receiving apparatus, which is the receiving apparatus serving as a

transmission destination of a transmission signal, and second receiving apparatuses, which is the receiving apparatuses other than the first receiving apparatus; and
a second step of performing precoding on signals transmitted from the transmission antennas such that received power in third receiving apparatuses, which are the receiving apparatuses excluding the first receiving apparatus and the second receiving apparatuses is equal to or smaller than a threshold.