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

• US 20140307630A1
• Filed: 11/01/2012
• Published: 10/16/2014
• Est. Priority Date: 11/07/2011
• Status: Active Grant

• Current Assignee: NTT Docomo Incorporated (Nippon Telegraph and Telephone Corporation)
• Original Assignee: NTT Docomo Incorporated (Nippon Telegraph and Telephone Corporation)
• Inventors: Nagata, Satoshi, Kishiyama, Yoshihisa, Takeda, Kazuaki, She, Xiaoming
• Granted Patent: US 9,337,907 B2
• Time in Patent Office: Days
• US Class Current: 370/328
• CPC Class Codes: H04B 7/024 Co-operative use of antennas of several sites, e.g. in co-ordinated multipoint or co-operative multiple-input multiple-output [MIMO] systems
• CPC Class Codes: H04L 25/0202 Channel estimation
• CPC Class Codes: H04L 25/0224 using sounding signals
• CPC Class Codes: H04L 25/0226 sounding signals per se
• CPC Class Codes: H04L 5/0051 of dedicated pilots, i.e. pilots destined for a single user or terminal
• CPC Class Codes: H04W 76/15 Setup of multiple wireless link connections

Abstract

To enable a user terminal to determine a cell of a downlink signal also in a heterogeneous environment using the same cell identification information, and thereby enable reception accuracy to be maintained, a radio communication method of the invention is characterized in that a radio base station apparatus generates a reference signal sequence by using a pseudo random sequence including user specific information, and transmits the reference signal sequence to a user terminal, and that the user terminal performs signal processing using the reference signal sequence transmitted from the radio base station apparatus.

Claims

1. A radio communication system comprising:

a plurality of radio base station apparatuses; and

a user terminal configured to be able to perform Coordinated Multi-Point transmission/reception with the plurality of radio base station apparatuses,

wherein the radio base station apparatus has a generation section configured to generate a reference signal sequence by using a pseudo random sequence using user specific information, and a transmission section configured to transmit the reference signal sequence to a user terminal, and

the user terminal has a signal processing section configured to perform signal processing using the reference signal sequence transmitted from the radio base station apparatus.

2. The radio communication system according to claim 1, wherein the reference signal sequence is a demodulation reference signal, and the signal processing section is a demodulation section configured to demodulate a reception signal.

3. The radio communication system according to claim 2, wherein the generation section is configured to generate a reference signal sequence by using user specific information as a substitute for cell identification information in a pseudo random sequence.

4. The radio communication system according to claim 2, wherein the generation section is configured to generate a reference signal sequence by using user specific information as a substitute for scrambling identification information in a pseudo random sequence.

5. The radio communication system according to claim 1, wherein the reference signal sequence is a channel state information reference signal, and the signal processing section is a feedback information generating section configured to generate feedback information.

6. The radio communication system according to claim 5, wherein the generation section is configured to generate a reference signal sequence by adding user specific information in a pseudo random sequence.

7. The radio communication system according to claim 5, wherein the radio base station apparatus is configured to notify the user terminal of information of whether to add the user specific information by higher layer signaling.

8. The radio communication system according to claim 1, wherein the plurality of radio base station apparatuses constitutes an overlay type network in which a plurality of low transmission power apparatuses is provided in a cover area of a macro base station, and cell identification information of the macro base station is the same as cell identification information of the low transmission power apparatuses.

9. A radio base station apparatus in a radio communication system provided with a plurality of radio base station apparatuses, and a user terminal configured to be able to perform Coordinated Multi-Point transmission/reception with the plurality of radio base station apparatuses, comprising:

a generation section configured to generate a reference signal sequence by using a pseudo random sequence using user specific information; and

a transmission section configured to transmit the reference signal sequence to a user terminal.

10. A user terminal in a radio communication system provided with a plurality of radio base station apparatuses, and a user terminal configured to be able to perform Coordinated Multi-Point transmission/reception with the plurality of radio base station apparatuses, comprising:

a signal processing section configured to perform signal processing using a reference signal sequence which is generated by using a pseudo random sequence using user specific information and which is transmitted from the radio base station apparatus.

11. A radio communication method in a radio communication system provided with a plurality of radio base station apparatuses, and a user terminal configured to be able to perform Coordinated Multi-Point transmission/reception with the plurality of radio base station apparatuses, comprising:

in the radio base station apparatus, generating a reference signal sequence by using a pseudo random sequence using user specific information;

transmitting the reference signal sequence to a user terminal; and

in the user terminal, performing signal processing using the reference signal sequence transmitted from the radio base station apparatus.