COMMUNICATION SYSTEM, BASE STATION APPARATUS, TERMINAL APPARATUS, AND COMMUNICATION METHOD

• US 20150180632A1
• Filed: 06/18/2013
• Published: 06/25/2015
• Est. Priority Date: 07/25/2012
• Status: Active Grant

• Current Assignee: NTT Docomo Incorporated (Nippon Telegraph and Telephone Corporation)
• Original Assignee: NTT Docomo Incorporated (Nippon Telegraph and Telephone Corporation)
• Inventors: Kishiyama, Yoshihisa, Nagata, Satoshi
• Granted Patent: US 9,628,235 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: H04L 5/0051 of dedicated pilots, i.e. pilots destined for a single user or terminal
• CPC Class Codes: H04W 24/08 Testing, supervising or monitoring using real traffic
• CPC Class Codes: H04W 52/04 TPC

Abstract

The present invention is designed to provide a communication system, a base station apparatus, a terminal apparatus and a communication method that can support the diversification of communication. In the communication system of the present invention, in which a terminal apparatus receives a downlink data signal transmitted from a base station apparatus (eNB) in a radio resource region for a downlink data signal, the base station apparatus transmits a terminal-specific reference signal in the radio resource region for the downlink data signal to the terminal apparatus (UE), and the terminal apparatus measures channel quality information based on the terminal-specific reference signal and transmits the measured channel quality information to the base station apparatus.

Claims

1. A communication system in which a terminal apparatus receives a downlink data signal transmitted from a base station apparatus in a radio resource region for a downlink data signal, wherein:

the base station apparatus transmits a terminal-specific reference signal in the radio resource region for the downlink data signal to the terminal apparatus; and

the terminal apparatus measures channel quality information based on the terminal-specific reference signal and transmits the measured channel quality information to the base station apparatus.

2. The communication system according to claim 1, wherein:

the base station apparatus periodically transmits a cell-specific reference signal to the terminal apparatus; and

the terminal apparatus measures the channel quality information based on the terminal-specific reference signal and the cell-specific reference signal, and transmits the measured channel quality information to the base station apparatus.

3. The communication system according to claim 2, wherein the terminal-specific reference signal is a DM-RS (DeModulation-Reference Signal), and the cell-specific reference signal is a CSI-RS (Channel State Information-Reference Signal).

4. The communication system according to claim 3, wherein the base station apparatus determines a modulation scheme and a coding rate based on the channel quality information.

5. The communication system according to claim 1, wherein, when at least beam forming or transmission power control is applied to the downlink transmission, the terminal apparatus measures the channel quality information based on the terminal-specific reference signal.

6. The communication system according to claim 1, wherein the terminal apparatus transmits the channel quality information based on the terminal-specific reference signal to the base station apparatus with an ACK/NACK for the downlink data signal.

7. The communication system according to claim 6, wherein the base station apparatus includes, in downlink control information that is transmitted to the terminal apparatus, bit information that triggers a transmission of the channel quality information measured based on the terminal-specific reference signal to the base station apparatus.

11. The communication system according to claim 4, wherein, when at least beam forming or transmission power control is applied to the downlink transmission, the terminal apparatus measures the channel quality information based on the terminal-specific reference signal.

12. The communication system according to claim 4, wherein the terminal apparatus transmits the channel quality information based on the terminal-specific reference signal to the base station apparatus with an ACK/NACK for the downlink data signal.

8. A base station apparatus that transmits a downlink data signal received by a terminal apparatus in a radio resource region for a downlink data signal, the radio base station comprising:

a transmitting section that transmits a terminal-specific reference signal in the radio resource region for the downlink data signal to the terminal apparatus; and

a receiving section that receives channel quality information that is measured in the terminal apparatus based on the terminal-specific reference signal and transmitted.

9. A terminal apparatus that receives a downlink data signal transmitted in a radio resource region for a downlink data signal from a base station apparatus, the terminal apparatus comprising:

a receiving section that receives a terminal-specific reference signal transmitted in the radio resource region for the downlink data signal from the base station apparatus;

a channel quality information measurement section that measures channel quality information based on the received terminal-specific reference signal; and

a transmitting section that transmits the measured channel quality information to the base station apparatus.

10. A communication method in which a terminal apparatus receives a downlink data signal transmitted in a radio resource region for a downlink data signal from a base station apparatus, the communication method comprising the steps in which:

the base station apparatus transmits a terminal-specific reference signal in the radio resource region for the downlink data signal to the terminal apparatus; and

the terminal apparatus measures channel quality information based on the terminal-specific reference signal and transmits the measured channel quality to the base station apparatus.