TRANSMITTING APPARATUS, RECEIVING APPARATUS, CONTROL STATION, COMMUNICATION SYSTEM, AND TRANSMISSION PRECODING METHOD

• US 20180069608A1
• Filed: 05/26/2016
• Published: 03/08/2018
• Est. Priority Date: 07/09/2015
• Status: Active Grant

• Current Assignee: Mitsubishi Electric Corporation
• Original Assignee: Mitsubishi Electric Corporation
• Inventors: NISHIMOTO, Hiroshi, TAIRA, Akinori
• Granted Patent: US 10,090,898 B2
• Time in Patent Office: Days
• CPC Class Codes: H04B 7/04 using two or more spaced independent antennas
• CPC Class Codes: H04B 7/0408 using two or more beams, i.e. beam diversity
• CPC Class Codes: H04B 7/0426 Power distribution
• CPC Class Codes: H04B 7/0452 Multi-user MIMO systems
• CPC Class Codes: H04B 7/0456 Selection of precoding matrices or codebooks, e.g. using matrices antenna weighting
• CPC Class Codes: H04B 7/0617 for beam forming
• CPC Class Codes: H04B 7/10 Polarisation diversity; Directional diversity
• CPC Class Codes: H04W 16/28 using beam steering

Abstract

A transmitting apparatus according to the present invention includes transmission antennas capable of forming a plurality of beams respectively directed to a plurality of terminals and a precoder unit that performs precoding on signals transmitted from the transmission antennas such that received power in the terminals excluding a desired terminal serving as a transmission destination of a transmission signal and two or more IUI terminals, which are the terminals other than the desired terminal, is equal to or smaller than a threshold.

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 two or more second receiving apparatuses among 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, 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, 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, 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 claim 1, further comprising an ordering processor to determine order of the receiving apparatuses in the precoding.

7. The transmitting apparatus according to claim 6, wherein

the ordering processor 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.

10. 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.

11. The transmitting apparatus according to claim 10, wherein the ordering processor performs the ordering such that the receiving apparatuses continuous in order are geographically close to or separated from each other.

13. The transmitting apparatus according to claim 10, further comprising an interference remover to perform sequential interference removal, wherein

when K is an integer equal to or larger than two and L is an integer equal to or larger than two, a precoding matrix for setting first to K-th receiving apparatuses among the receiving apparatuses ordered by the ordering unit as the first receiving apparatus is a matrix for performing the precoding such that the received power in the third receiving apparatus is equal to or smaller than the threshold and a precoding matrix for setting K+1-th and subsequent receiving apparatuses among the receiving apparatuses 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 and the second receiving apparatuses fewer than L, and

the interference remover sequentially carries out, as the sequential interference removal, processing for removing interference that occurs in the receiving apparatuses next in order.

15. The transmitting apparatus according to claim 6, wherein the ordering unit processor 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.

16. The transmitting apparatus according to claim 6, wherein the ordering processor 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.

17. A receiving apparatus that receives signals transmitted from the transmitting apparatus according to claim 1, the receiving apparatus comprising a decoder to extract a desired signal from the signals received from the transmitting apparatus.

8-9. -9. (canceled)

12. (canceled)

14. (canceled)

18-21. -21. (canceled)

22. 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 calculator 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 two or more second receiving apparatuses among the receiving apparatuses, is equal to or smaller than a threshold, and

a transceiver to transmit the precoding matrix to the transmitting apparatuses.

23-24. -24. (canceled)

25. 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 two or more second receiving apparatuses, which are 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 the receiving apparatuses excluding the first receiving apparatus and the second receiving apparatuses is equal to or smaller than a threshold.