USER TERMINAL RADIO BASE STATION AND RADIO COMMUNICATION METHOD

• US 20150327230A1
• Filed: 11/12/2013
• Published: 11/12/2015
• Est. Priority Date: 12/17/2012
• 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, Uchino, Tooru, Sagae, Yuta, Takahashi, Hideaki
• Granted Patent: US 9,781,705 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: H04L 1/1607 Details of the supervisory signal
• CPC Class Codes: H04L 1/1861 Physical mapping arrangements for ACK signaling see also H04L5/0053
• CPC Class Codes: H04L 5/001 the frequencies being arranged in component carriers
• CPC Class Codes: H04L 5/0055 Physical resource allocation for ACK/NACK for physical mapping arrangements in ARQ protocols H04L1/1861
• CPC Class Codes: H04W 72/04 Wireless resource allocation
• CPC Class Codes: H04W 72/20 Control channels or signalling for resource management

Abstract

In order to control feedback control information in uplink transmission appropriately even when using carrier aggregation in HetNet, the present invention provides a user terminal that is able to communicate with a plurality of radio base stations having overlapping coverage areas by using carrier aggregation, the user terminal comprising: a reception section that receives downlink shared channel signals using component carriers of a primary cell and a secondary cell; a generating section that generates transmission acknowledgement signals in response to the downlink shared channel signals; and an allocating section that allocates the transmission acknowledgement signals to predetermined uplink control channel resources, wherein the allocating section allocates the transmission acknowledgement signals to either or both of uplink control channel resources of the primary cell and uplink control channel resources of the secondary cell in accordance with contents of the transmission acknowledgement signals and/or an uplink control channel format.

Claims

1. A user terminal that is able to communicate with a plurality of radio base stations having overlapping coverage areas by using carrier aggregation, the user terminal comprising:

a reception section that receives downlink shared channel signals using component carriers of a primary cell and a secondary cell;

a generating section that generates transmission acknowledgement signals in response to the downlink shared channel signals; and

an allocating section that allocates the transmission acknowledgement signals to predetermined uplink control channel resources,

wherein the allocating section allocates the transmission acknowledgement signals to either or both of uplink control channel resources of the primary cell and uplink control channel resources of the secondary cell in accordance with contents of the transmission acknowledgement signals and/or an uplink control channel format.

2. The user terminal according to claim 1, wherein, when the carrier aggregation is applied to two cells, the uplink control channel resources of the primary cell and the uplink control channel resources of the secondary cell are configured as uplink control channel resource candidates for allocating the transmission acknowledgement signals, and the allocating section allocates the transmission acknowledgement signals to either of the uplink control channel resources of the primary cell and the uplink control channel resources of the secondary cell in accordance with the contents of the transmission acknowledgement signals.

3. The user terminal according to claim 2, wherein the allocating section determines the uplink control channel resources of the primary cell to allocate the transmission acknowledgement signals, using a CCE index of downlink control channels corresponding to downlink shared channel signals of the primary cell and determines the uplink control channel resources of the secondary cell to allocate the transmission acknowledgement signals, using a CCE index of downlink control channels corresponding to downlink shared channel signals of the secondary cell.

4. The user terminal according to claim 1, wherein, when the carrier aggregation is applied to three or more cells, uplink control channel resources of a plurality of secondary cells are configured as uplink control channel resource candidates for allocating the transmission acknowledgement signals, and the allocating section allocates the transmission acknowledgement signals to the predetermined uplink control channel resources from the uplink control channel resources of the plurality of secondary cells, based on downlink control information of the secondary cells.

5. The user terminal according to claim 4, wherein the uplink control channel resources of the plurality of secondary cells are given by higher layer signaling.

6. The user terminal according to claim 4, wherein, when the carrier aggregation is applied to three or more cells and the user terminal does not receive the downlink control information from the secondary cells, the allocating section allocates the transmission acknowledgement signals to the uplink control channel resources of the primary cell.

7. The user terminal according to claim 1, wherein the allocating section allocates transmission acknowledgement signals in response to downlink shared channel signals of the primary cell to the uplink control channel resources of the primary cell that are determined using a CCE index of downlink control channels corresponding to the downlink shared channel signals of the primary cell, and the allocating section allocates transmission acknowledgement signals in response to downlink shared channel signals of the secondary cell to the uplink control channel resources of the secondary cell that are determined using a CCE index of downlink control channels corresponding to the downlink shared channel signals of the secondary cell.

8. A radio base station in a radio communication system in which a user terminal is able to communicate with a plurality of radio base stations having overlapping coverage areas by using carrier aggregation, the radio base station comprising:

a transmission section that transmits downlink shared channel signals to the user terminal; and

a control section that controls retransmission based on transmission acknowledgement signals that are fed back from the user terminal in response to the downlink shared channel signals,

wherein the transmission section notifies the user terminal of uplink control channel resources of a plurality of secondary cells as uplink control channel resource candidates for allocating the transmission acknowledgement signals for the user terminal to feed back.

9. A radio communication method for allowing a plurality of radio base stations having overlapping coverage areas and a user terminal to communicate using carrier aggregation, the radio communication method comprising the steps of:

transmitting, from the plurality of radio base stations to the user terminal, downlink shared channel signals using component carriers of a primary cell and a secondary cell;

in the user terminal, generating transmission acknowledgement signals in response to the downlink shared channel signals, and allocating the transmission acknowledgement signals to predetermined uplink control channel resources,

wherein the user terminal allocates the transmission acknowledgement signals to either or both of uplink control channel resources of the primary cell and uplink control channel resources of the secondary cell in accordance with contents of the transmission acknowledgement signals and/or an uplink control channel format.