Radio communication control method and radio communication system

• US 10,116,370 B2
• Filed: 03/23/2016
• Issued: 10/30/2018
• Est. Priority Date: 03/26/2015
• Status: Active Grant

• Current Assignee: NTT Docomo Incorporated (Nippon Telegraph and Telephone Corporation)
• Original Assignee: NTT Docomo Incorporated (Nippon Telegraph and Telephone Corporation)
• Inventors: Obara, Tatsunori, Suyama, Satoshi, Shen, Jiyun, Okumura, Yukihiko
• Primary Examiner(s): Perez, James M
• Application Number:
  US15/561,413
• Publication Number:
  US 20180109305A1
• Time in Patent Office: 951 Days
• Field of Search: 375259-285, 375295-296, 375316-352
• CPC Class Codes: H04B 7/04 using two or more spaced independent antennas
• CPC Class Codes: H04B 7/0617 for beam forming
• CPC Class Codes: H04B 7/0695 using beam selection
• CPC Class Codes: H04B 7/08 at the receiving station
• CPC Class Codes: H04B 7/088 using beam selection
• CPC Class Codes: H04B 7/10 Polarisation diversity; Directional diversity
• CPC Class Codes: H04W 16/28 using beam steering
• CPC Class Codes: H04W 88/02 Terminal devices

Abstract

A number L_R of receive beamforming circuits provided in a receive beamformer execute receive beamforming (N_R/L_R) times with respect to a received signal vector received by N_R reception antennas A_R, thereby generating a receive beamforming (BF) output vector having N_R receive BF output components. A calculation processor calculates a reception power for each of the N_R receive BF output components, selects L_R receive BF output components in decreasing order of reception power, and determines a suitable receive BF weight matrix including L_R reception orthogonal BF weight vectors corresponding to the selected receive BF output components.

Claims

1. A radio communication control method in a radio communication system, comprising

a transmitter device provided with

a precoder configured to carry out precoding by using a precoding matrix,

a transmit beamformer configured to carry out transmit beamforming, in which variation in phase and amplitude corresponding to a transmit beamforming (BF) weight matrix is imparted to signals after precoding has been executed, and

a number NT of transmission antennas for transmitting the signals subjected to the transmit beamforming, and

a receiver device provided with

a number NR of reception antennas for receiving signals that have been transmitted from the transmitter device and propagated through a space,

a receive beamformer configured to carry out receive beamforming, in which variation in phase and amplitude corresponding to a receive BF weight matrix is imparted to the signals received by the plurality of reception antennas, and

a postcoder configured to carry out, by using a postcoding matrix, postcoding on the signals that have been subjected to the analog receive beamforming,

the method comprising:

generating a receive BF output vector having a number NR of receive BF output components, by a number LR of receive beamforming circuits provided in the receive beamformer carrying out receive beamforming (NR/LR) times with respect to a received signal vector received by the number NR of the reception antennas;

calculating reception power for each of the NR receive BF output components; and

selecting the LR receive BF output components in decreasing order of reception power, and determining a suitable receive BF weight matrix including LR reception orthogonal BF weight vectors corresponding to the selected receive BF output components.

2. The radio communication control method according to claim 1, further comprising:

prior to the determining of the suitable receive BF weight matrix,

selecting a candidate transmit BF weight vector from among a plurality of transmit BF weight vector candidates;

transmitting, from the NT transmission antennas, a reference signal subjected to analog transmit beamforming based on a candidate transmit BF weight matrix including the selected candidate transmit BF weight vector;

generating a receive BF output vector having a number NR of receive BF output components, by a number LR of receive beamforming circuits carrying out receive beamforming (NR/LR) times with respect to a received signal vector corresponding to the reference signal received by the number NR of the reception antennas;

calculating the sum of the reception power of the receive BF output vectors;

acquiring a plurality of the sums of reception power by executing the selection, transmission, generation and calculation on a plurality of the transmit BF weight vector candidates; and

selecting the LT transmit BF weight vector candidates in decreasing order of the sum of reception power, and determining a suitable BF weight matrix including the selected LT transmit BF weight vector candidates.

3. The radio communication control method according to claim 2, further comprising:

transmitting, from the transmitter device, a reference signal subjected to analog transmit beamforming based on the suitable transmit BF weight matrix;

estimating an equivalent channel matrix indicating a result of the reference signal received by the receiver device being subjected to analog receive beamforming based on the suitable receive BF weight matrix; and

determining a suitable precoding matrix and a suitable postcoding matrix based on the estimated equivalent channel matrix.

4. A radio communication control method in a radio communication system, comprising

a transmitter device provided with

a precoder configured to carry out precoding by using a precoding matrix,

a transmit beamformer configured to carry out transmit beamforming, in which variation in phase and amplitude corresponding to a transmit beamforming (BF) weight matrix is imparted to signals after precoding has been executed, and

a number NT of transmission antennas for transmitting the signals that have been subjected to the transmit beamforming, and

a receiver device provided with

a number NR of reception antennas for receiving signals that have been transmitted from the transmitter device and propagated through a space,

a receive beamformer configured to carry out receive beamforming, in which variation in phase and amplitude corresponding to a receive BF weight matrix is imparted to the signals received by the plurality of reception antennas, and

a postcoder configured to carry out, by using a postcoding matrix, postcoding on the signals that have been subjected to the analog receive beamforming,

the method comprising:

generating a receive BF output vector having a number NR of receive BF output components, by a number LR of receive beamforming circuits provided in the receive beamformer carrying out receive beamforming (NR/LR) times with respect to a received signal vector received by the number NR of the reception antennas;

acquiring the received signal vector by multiplying each of a number NR of separation operators corresponding to the NR reception antennas with respect to the receive BF output vector;

estimating a channel matrix using the received signal vector;

calculating reception power for each of a plurality of receive BF weight vector candidates using the estimated channel matrix; and

selecting the LR receive BF weight vector candidates in decreasing order of reception power, and determining a suitable receive BF weight matrix including the selected LR receive BF weight vector candidates.

5. The radio communication control method according to claim 4, further comprising:

prior to the determining of the suitable receive BF weight matrix,

selecting a candidate transmit BF weight vector from among a plurality of transmit BF weight vector candidates;

transmitting, from the NT transmission antennas, a reference signal subjected to analog transmit beamforming based on a candidate transmit BF weight matrix including the selected candidate transmit BF weight vector;

generating a receive BF output vector having a number NR of receive BF output components, by a number LR of receive beamforming circuits carrying out receive beamforming (NR/LR) times with respect to a received signal vector corresponding to the reference signal received by the number NR of the reception antennas;

calculating the sum of the reception power of the receive BF output vectors;

acquiring a plurality of the sums of reception power by executing the selection, transmission, generation and calculation on a plurality of the transmit BF weight vector candidates; and

selecting the LT transmit BF weight vector candidates in decreasing order of the sum of reception power, and determining a suitable BF weight matrix including the selected LT transmit BF weight vector candidates.

6. The radio communication control method according to claim 5, further comprising:

transmitting, from the transmitter device, a reference signal subjected to analog transmit beamforming based on the suitable transmit BF weight matrix;

estimating an equivalent channel matrix indicating a result of the reference signal received by the receiver device being subjected to analog receive beamforming based on the suitable receive BF weight matrix; and

determining a suitable precoding matrix and a suitable postcoding matrix based on the estimated equivalent channel matrix.

7. A radio communication control method in a radio communication system, comprising

a transmitter device provided with

a precoder configured to carry out precoding by using a precoding matrix,

a transmit beamformer configured to carry out transmit beamforming, in which variation in phase and amplitude corresponding to a transmit beamforming (BF) weight matrix is imparted to signals after precoding has been executed, and

a number NT of transmission antennas for transmitting the signals that have been subjected to the transmit beamforming, and

a receiver device provided with

a number NR of reception antennas for receiving signals that have been transmitted from the transmitter device and propagated through a space,

a receive beamformer configured to carry out receive beamforming, in which variation in phase and amplitude corresponding to a receive BF weight matrix is imparted to the signals received by the plurality of reception antennas, and

a postcoder configured to carry out, by using a postcoding matrix, postcoding on the signals that have been subjected to the analog receive beamforming,

the method comprising:

acquiring a received signal vector, by each of a number LR of receive beamforming circuits provided in the receive beamformer carrying out a bypass receiving operation that selects and acquires one of the received signal vector elements (NR/LR) times with respect to the received signal vector received by the number NR of the reception antennas;

estimating a channel matrix using the received signal vector;

calculating reception power for each of a plurality of receive BF weight vector candidates using the estimated channel matrix; and

selecting the LR receive BF weight vector candidates in decreasing order of reception power, and determining a suitable receive BF weight matrix including the selected LR receive BF weight vector candidates.

8. The radio communication control method according to claim 7, further comprising:

prior to the determining of the suitable receive BF weight matrix,

selecting a candidate transmit BF weight vector from among a plurality of transmit BF weight vector candidates;

transmitting, from the NT transmission antennas, a reference signal subjected to analog transmit beamforming based on a candidate transmit BF weight matrix including the selected candidate transmit BF weight vector;

generating a receive BF output vector having a number NR of receive BF output components, by a number LR of receive beamforming circuits carrying out receive beamforming (NR/LR) times with respect to a received signal vector corresponding to the reference signal received by the number NR of the reception antennas;

calculating the sum of the reception power of the receive BF output vectors;

acquiring a plurality of the sums of reception power by executing the selection, transmission, generation and calculation on a plurality of the transmit BF weight vector candidates; and

selecting the LT transmit BF weight vector candidates in decreasing order of the sum of reception power, and determining a suitable BF weight matrix including the selected LT transmit BF weight vector candidates.

9. The radio communication control method according to claim 8, further comprising:

transmitting, from the transmitter device, a reference signal subjected to analog transmit beamforming based on the suitable transmit BF weight matrix;

estimating an equivalent channel matrix indicating a result of the reference signal received by the receiver device being subjected to analog receive beamforming based on the suitable receive BF weight matrix; and

determining a suitable precoding matrix and a suitable postcoding matrix based on the estimated equivalent channel matrix.

10. A radio communication system, comprising

a transmitter device provided with

a precoder configured to carry out precoding by using a precoding matrix,

a transmit beamformer configured to carry out transmit beamforming, in which variation in phase and amplitude corresponding to a transmit beamforming (BF) weight matrix is imparted to signals after precoding has been executed, and

a number NT of transmission antennas for transmitting the signals that have been subjected to the transmit beamforming, and

a receiver device provided with

a number NR of reception antennas for receiving signals that have been transmitted from the transmitter device and propagated through a space,

a receive beamformer configured to carry out receive beamforming, in which variation in phase and amplitude corresponding to a receive BF weight matrix is imparted to the signals received by the plurality of reception antennas, and

a postcoder configured to carry out, by using a postcoding matrix, postcoding on the signals that have been subjected to the analog receive beamforming, wherein,

the receive beamformer generates a receive BF output vector having a number NR of receive BF output components, by a number LR of receive beamforming circuits provided in the receive beamformer carrying out receive beamforming (NR/LR) times with respect to a received signal vector received by the number NR of the reception antennas, and

the receiver device is further provided with a calculation processor configured to

calculate reception power for each of the NR receive BF output components, and

select the LR receive BF output components in decreasing order of reception power, and determine a suitable receive BF weight matrix including LR reception orthogonal BF weight vectors corresponding to the selected receive BF output components.

11. A radio communication system, comprising

a transmitter device provided with

a precoder configured to carry out precoding by using a precoding matrix,

a transmit beamformer configured to carry out transmit beamforming, in which variation in phase and amplitude corresponding to a transmit BF weight matrix is imparted to signals after precoding has been executed, and

a number NT of transmission antennas for transmitting the signals that have been subjected to the transmit beamforming, and

a receiver device provided with

a number NR of reception antennas for receiving signals that have been transmitted from the transmitter device and propagated through a space,

a receive beamformer configured to carry out receive beamforming, in which variation in phase and amplitude corresponding to a receive BF weight matrix is imparted to the signals received by the plurality of reception antennas, and

a postcoder configured to carry out, by using a postcoding matrix, postcoding on the signals that have been subjected to the analog receive beamforming, wherein,

the receive beamformer generates a receive BF output vector having a number NR of receive BF output components, by a number LR of receive beamforming circuits provided in the receive beamformer carrying out receive beamforming (NR/LR) times with respect to a received signal vector received by the number NR of the reception antennas,

the receiver device is further provided with a calculation processor configured to

acquire the received signal vector by multiplying each of a number NR of separation operators corresponding to the NR reception antennas with respect to the receive BF output vector,

estimate a channel matrix using the received signal vector,

calculate reception power for each of a plurality of receive BF weight vector candidates using the estimated channel matrix, and

select the LR receive BF weight vector candidates in decreasing order of reception power, and determine a suitable receive BF weight matrix including the selected LR receive BF weight vector candidates.

12. A radio communication system, comprising

a transmitter device provided with

a precoder configured to carry out precoding by using a precoding matrix,

a transmit beamformer configured to carry out transmit beamforming, in which variation in phase and amplitude corresponding to a transmit BF weight matrix is imparted to signals after precoding has been executed, and

a number NT of transmission antennas for transmitting the signals that have been subjected to the transmit beamforming, and

a receiver device provided with

a number NR of reception antennas for receiving signals that have been transmitted from the transmitter device and propagated through a space,

a receive beamformer configured to carry out receive beamforming, in which variation in phase and amplitude corresponding to a receive BF weight matrix is imparted to the signals received by the plurality of reception antennas, and

a postcoder configured to carry out, by using a postcoding matrix, postcoding on the signals that have been subjected to the analog receive beamforming, wherein,

each of a number LR of receive beamforming circuits provided in the receive beamformer carries out a bypass receiving operation that selects and acquires one of the received signal vector elements (NR/LR) times with respect to a received signal vector received by the number NR of the reception antennas, to acquire the received signal vector,

the receiver device is further provided with a calculation processor configured to

estimate a channel matrix using the received signal vector,

calculate reception power for each of a plurality of receive BF weight vector candidates using the estimated channel matrix, and

select the LR receive BF weight vector candidates in decreasing order of reception power, and determine a suitable receive BF weight matrix including the selected LR receive BF weight vector candidates.