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

• US 20150195830A1
• Filed: 07/26/2013
• Published: 07/09/2015
• Est. Priority Date: 08/02/2012
• Status: Active Grant

• Current Assignee: NTT Docomo Incorporated (Nippon Telegraph and Telephone Corporation)
• Original Assignee: NTT Docomo Incorporated (Nippon Telegraph and Telephone Corporation)
• Inventors: Takeda, Kazuaki, Kishiyama, Yoshihisa, Kiyoshima, Kohei, Nagata, Satoshi
• Granted Patent: US 9,749,998 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: H04B 7/0626 Channel coefficients, e.g. channel state information [CSI]
• CPC Class Codes: H04L 1/0026 Transmission of channel quality indication
• CPC Class Codes: H04L 1/0031 Multiple signaling transmission H04L1/1664, F15 take precedence
• CPC Class Codes: H04L 27/2636 with FFT or DFT modulators, e.g. standard single-carrier frequency-division multiple access [SC-FDMA] transmitter or DFT spread orthogonal frequency division multiplexing [DFT-SOFDM]
• CPC Class Codes: H04L 5/001 the frequencies being arranged in component carriers
• CPC Class Codes: H04L 5/0057 Physical resource allocation for CQI
• CPC Class Codes: H04L 5/0064 Rate requirement of the data, e.g. scalable bandwidth, data priority
• CPC Class Codes: H04W 24/10 Scheduling measurement reports ; Arrangements for measurement reports
• CPC Class Codes: H04W 72/21 in the uplink direction of a wireless link, i.e. towards the network

Abstract

A radio communication method of a user terminal and a radio base station adopting carrier aggregation to adequately feed back channel state information of a plurality of cells from a user terminal to a radio base station, is disclosed. The user terminal generates channel state information of each cell in uplink control channel format 2 or in format 3 based on the number of cells to use in carrier aggregation, feeds back the generated channel state information via resources that the radio base station sets in an uplink control channel of a primary cell at a predetermined time in accordance with an uplink control channel format, and the radio base station secures the resources to set in the uplink control channel when the channel state information of the primary cell is generated in uplink control channel format 2, regardless of the number of cells to use in carrier aggregation.

Claims

1. A radio communication method of a user terminal and a radio base station adopting carrier aggregation, the radio communication method comprising the steps in which:

the user terminal;

generates channel state information of each cell in uplink control channel format 2 or in format 3 based on the number of cells to use in carrier aggregation; and

feeds back the generated channel state information via resources that the radio base station sets in an uplink control channel of a primary cell at a predetermined time in accordance with an uplink control channel format; and

the radio base station secures the resources to set in the uplink control channel when the channel state information of the primary cell is generated in uplink control channel format 2, regardless of the number of cells to use in carrier aggregation.

2. The radio communication method according to claim 1, wherein the user teiminal generates the channel state information of the primary cell and a secondary cell in uplink control channel format 2 when the number of primary cells and secondary cells to use in carrier aggregation is smaller than a predetermined number, generates the channel state information of the primary cell in uplink control channel format 2 when the number of primary cells and secondary cells is equal to or larger than the predetermined number, and generates the channel state information of a plurality of secondary cells in uplink control channel format 3.

3. The radio communication method according to claim 1, wherein, the user terminal generates the channel state information of the primary cell and the secondary cell in uplink control channel format 2 when the number of primary cells and secondary cells to use in carrier aggregation is smaller than a predetermined number, and generates the channel state information of the primary cell and the secondary cell in uplink control channel format 3 when the number of primary cells and secondary cells is equal to or larger than the predetermined number.

4. The radio communication method according to claim 1, wherein the user terminal generates the channel state information of a secondary cell in uplink control channel format 3, regardless of the number of primary cells and secondary cells to use in carrier aggregation.

5. The radio communication method according to claim 1, wherein the user terminal sets the channel state information of different cells generated in uplink control channel format 2, in uplink control channel resources of varying subframes, and sets the channel state information of different cells generated in uplink control channel format 3, in uplink control channel resources of a same subframe.

6. The radio communication method according to claim 1, wherein, when a state, in which the channel state information of a plurality of secondary cells is generated in uplink control channel format 3 and fed back in a same subframe, is changed to a state, in which one of the plurality of secondary cells is deactivated by MAC control, the user terminal makes the channel state information of the deactivated secondary cell a fixed value, generates the channel state information of the plurality of secondary cells in uplink control channel format 3, and feeds back in the same subframe.

7. The radio communication method according to claim 1, wherein, when a state, in which the channel state information of a plurality of secondary cells is generated in uplink control channel format 3 and fed back in a same subframe, is changed to a state, in which one of the plurality of secondary cells is deactivated by MAC control, the user terminal makes the channel state information of the deactivated secondary cell out-of-range, generates the channel state information of the plurality of secondary cells in uplink control channel format 3, and feeds back in the same subframe.

8. The radio communication method according to claim 1, wherein, when a state, in which the channel state information of a plurality of secondary cells is generated in uplink control channel format 3 and fed back in a same subframe, is changed to a state, in which all of the plurality of secondary cells are deactivated by MAC control, the user terminal makes the channel state information of all the secondary cells out-of-range, generates the channel state information of the plurality of secondary cells in uplink control channel format 3, and feeds back in the same subframe.

9. The radio communication method according to claim 1, wherein, when a state, in which the channel state information of a plurality of secondary cells is generated in uplink control channel format 3 and fed back in a same subframe, is changed to a state, in which all of the plurality of secondary cells are deactivated by MAC control, the user terminal stops the feedback of the channel state information of all the secondary cells.

10. A radio communication system having a user terminal and a radio base station adopting carrier aggregation, the radio communication comprising the steps in which:

the user terminal;

generates channel state information of each cell in uplink control channel format 2 or in format 3 based on the number of cells to use in carrier aggregation; and

feeds back the generated channel state information via resources that the radio base station sets in an uplink control channel of a primary cell at a predetermined time in accordance with an uplink control channel format; and

the radio base station secures the resources to set in the uplink control channel when the channel state information of the primary cell is generated in uplink control channel format 2, regardless of the number of cells to use in carrier aggregation.

11. A radio base station that adopts carrier aggregation and communicates with a user terminal, the radio base station comprising:

a setting section that, in response to channel state information that is fed back from the user terminal, sets resources for an uplink control channel of a primary cell at a predetermined time in accordance with an uplink control channel format applied to the channel state information; and

a transmission section that reports the set resources to the user terminal by higher layer signaling,

wherein the setting section secures the resources to set in the uplink control channel when the channel state information of the primary cell is generated in uplink control channel format 2, regardless of the number of cells to use in carrier aggregation.

12. A user terminal that adopts carrier aggregation and communicates with a radio base station, the user terminal comprising:

a generating section that generates channel state information of each cell in uplink control channel format 2 or in format 3 based on the number of cells to use in carrier aggregation; and

a transmission section that feeds back the generated channel state information via resources that the radio base station sets in an uplink control channel of a primary cell at a predetermined time in accordance with an uplink control channel format,

wherein the resources to set in the uplink control channel are secured when the channel state information of the primary cell is generated in uplink control channel format 2, regardless of the number of cells to use in carrier aggregation.

13. The radio communication method according to claim 2, wherein the user terminal sets the channel state information of different cells generated in uplink control channel format 2, in uplink control channel resources of varying subframes, and sets the channel state information of different cells generated in uplink control channel format 3, in uplink control channel resources of a same subframe.

14. The radio communication method according to claim 3, wherein the user terminal sets the channel state information of different cells generated in uplink control channel format 2, in uplink control channel resources of varying subframes, and sets the channel state information of different cells generated in uplink control channel format 3, in uplink control channel resources of a same subframe.

15. The radio communication method according to claim 4, wherein the user terminal sets the channel state information of different cells generated in uplink control channel format 2, in uplink control channel resources of varying subframes, and sets the channel state information of different cells generated in uplink control channel format 3, in uplink control channel resources of a same subframe.