RADIO BASE STATION, USER TERMINAL AND RADIO COMMUNICATION METHOD

• US 20180063819A1
• Filed: 03/18/2016
• Published: 03/01/2018
• Est. Priority Date: 03/31/2015
• Status: Abandoned Application

• Current Assignee: NTT Docomo Incorporated (Nippon Telegraph and Telephone Corporation)
• Original Assignee: NTT Docomo Incorporated (Nippon Telegraph and Telephone Corporation)
• Inventors: Saito, Keisuke, Benjebbour, Anass, Suyama, Satoshi
• Application Number:
  US15/558,282
• Publication Number:
  US 20180063819A1
• Time in Patent Office: Days
• CPC Class Codes: H04B 7/04 using two or more spaced independent antennas
• CPC Class Codes: H04B 7/0413 MIMO systems
• CPC Class Codes: H04B 7/0617 for beam forming
• CPC Class Codes: H04B 7/086 using weights depending on external parameters, e.g. direction of arrival [DOA], predetermined weights or beamforming
• CPC Class Codes: H04B 7/0862 receiver computing weights based on information from the transmitter
• CPC Class Codes: H04L 5/0048 Allocation of pilot signals, i.e. of signals known to the receiver
• CPC Class Codes: H04W 16/28 using beam steering
• CPC Class Codes: H04W 72/23 in the downlink direction of a wireless link, i.e. towards a terminal
• CPC Class Codes: H04W 88/02 Terminal devices

Abstract

To suppress deterioration of reception characteristics even in the case where a radio base station performs power multiplexing on downlink signals to transmit, a radio base station according to one aspect of the present invention has a transmission section that performs power multiplexing on downlink signals to a plurality of user terminals each having a MIMO configuration to transmit, and a control section that controls a phase rotation applied to the downlink signal to each user terminal, where the control section controls so as to apply different phase rotations to the downlink signals.

Claims

1. A radio base station comprising:

a transmission section that performs power multiplexing on downlink signals subsequent to precoding multiplication to a plurality of user terminals each having a MIMO (Multiple-Input Multiple-Output) configuration to transmit; and

a control section that controls a phase rotation applied to the downlink signal to each user terminal, wherein the control section controls so as to apply different phase rotations to the downlink signals subsequent to precoding multiplication.

2. The radio base station according to claim 1, wherein in the transmission section, a precoding weight multiplied by the downlink signal to each user terminal is different from one another.

3. The radio base station according to claim 1, wherein in the transmission section, a precoding weight multiplied by the downlink signal to each user terminal is the same.

4. The radio base station according to claim 1, wherein the transmission section transmits information on the phase rotation to the user terminal.

5. The radio base station according to claim 4, wherein the information on the phase rotation is an index associated with the phase rotation.

6. The radio base station according to claim 4, wherein the information on the phase rotation is information on only the presence or absence of the phase rotation.

7. The radio base station according to claim 1, wherein the control section controls so as to apply the same phase rotation as in a downlink data signal to a user terminal-specific reference signal.

8. The radio base station according to claim 1, wherein the control section controls so as to apply the phase rotation for each transmission layer.

11. The radio base station according to claim 2, wherein the transmission section transmits information on the phase rotation to the user terminal.

12. The radio base station according to claim 3, wherein the transmission section transmits information on the phase rotation to the user terminal.

13. The radio base station according to claim 2, wherein the control section controls so as to apply the same phase rotation as in a downlink data signal to a user terminal-specific reference signal.

14. The radio base station according to claim 3, wherein the control section controls so as to apply the same phase rotation as in a downlink data signal to a user terminal-specific reference signal.

9. A user terminal comprising:

a reception section that receives a power-multiplexed downlink signal; and

a received signal processing section that performs reception processing on the downlink signal, based on information on a phase rotation applied to the downlink signal,

wherein the phase rotation is different from a phase rotation applied to a downlink signal to another user terminal.

10. A radio communication method including:

performing power multiplexing on downlink signals subsequent to precoding multiplication to a plurality of user terminals each having a MIMO (Multiple-Input Multiple-Output) configuration to transmit; and

controlling so as to apply a different phase rotation to the downlink signal to each user terminal.