USER TERMINAL, RADIO COMMUNICATION METHOD AND RADIO COMMUNICATION SYSTEM

• US 20150208403A1
• Filed: 08/08/2013
• Published: 07/23/2015
• Est. Priority Date: 08/10/2012
• 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, Lu, Yang, Liu, Liu, Chen, Lan
• Granted Patent: US 9,345,009 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: H04L 1/00 Arrangements for detecting or preventing errors in the information received correcting synchronisation H04L7/00
• CPC Class Codes: H04L 1/1861 Physical mapping arrangements for ACK signaling see also H04L5/0053
• CPC Class Codes: H04L 1/1896 ARQ related signaling
• CPC Class Codes: H04L 5/0007 the frequencies being orthogonal, e.g. OFDM(A), DMT
• CPC Class Codes: H04L 5/001 the frequencies being arranged in component carriers
• CPC Class Codes: H04L 5/0053 Allocation of signaling, i.e. of overhead other than pilot signals
• CPC Class Codes: H04L 5/1469 using time-sharing
• CPC Class Codes: H04W 72/21 in the uplink direction of a wireless link, i.e. towards the network
• CPC Class Codes: H04W 72/23 in the downlink direction of a wireless link, i.e. towards a terminal

Abstract

A user terminal carries out the steps of receiving downlink control information for a first cell and a second cell allocated to the PDCCH of the first cell, generating retransmission control signals for each downlink data signal in predetermined PUCCH formats, allocating the generated retransmission control signals to a PUCCH resource of the first cell, and sending feedback, and, when the ratio of DL subframes is higher in the second cell than in the first cell, applies PUCCH format 3 to a retransmission control signal for a downlink data signal of the second cell demodulated by using downlink control information in which the CCE number is equal to or lower than a predetermined value, and applies PUCCH format 1b to a retransmission control signal for a downlink data signal of the second cell demodulated by using downlink control information in which the CCE number is greater than the predetermined value.

Claims

1. A radio communication method for a radio base station and a user terminal that adopt carrier aggregation between a first cell and a second cell and that communicate by way of time division duplexing, the radio communication method comprising the steps in which the user terminal:

receives downlink control information for the first cell and the second cell respectively, allocated to a downlink control channel of the first cell, by adopting cross-carrier scheduling;

determines retransmission control for downlink data signals transmitted through each cell;

generates retransmission control signals for each downlink data signal in predetermined uplink control channel formats; and

allocates the generated retransmission control signals to a resource of an uplink control channel of the first cell and sends feedback to the radio base station,

wherein, when a ratio of downlink subframes is higher in the second cell than in the first cell, uplink control channel format 3 is applied to a retransmission control signal for a downlink data signal of the second cell demodulated by using downlink control information in which an index number of a channel control element is equal to or lower than a predetermined value, and uplink control channel format 1b is applied to a retransmission control signal for a downlink data signal of the second cell demodulated by using downlink control information in which an index number of a channel control element is greater than the predetermined value.

2. The radio communication method according to claim 1, wherein the user terminal applies uplink control channel format 1b to a retransmission control signal for a downlink data signal of the second cell demodulated by using downlink control information in which an index number of a channel control element meets one of following condition 1 and condition 2:

n_cce>

N_X 

 

Condition 1;

n_cce>

N₁ and m_s>

Y 

 

Condition 2;

where;

N_X=max{0,└

[N_RB^DL×

(N_SC^RB×

X−

4]/36┘

};

X=┌

4M_PCell/M_SCell┐

;

Y=4M_PCell−

(X−

1)M_SCell−

1;

M_PCell;

the number of DL subframes in P-cell;

M_SCell;

the number of DL subframes in S-cell; and

m_s;

a subframe number of a subframe of second-cell of which to feed back a retransmission control signal.

3. The radio communication method according to claim 1, wherein, when applying uplink control channel format 1b to the retransmission control signal, the user terminal selects an uplink control channel resource, to which the retransmission control signal is allocated, using following equation 1:

4. The radio communication method according to claim 1, wherein, when applying uplink control channel format 3 to the retransmission control signal, the user terminal allocates the retransmission control signal to a predetermined uplink control channel resource that is designated by an ARI included in the downlink control information, from among a plurality of resources that are reported by higher layer signaling.

5. The radio communication method according to claim 1, wherein uplink control channel format 1b is applied to a retransmission control signal for a downlink data signal of the first cell.

8. The radio communication method according to claim 2, wherein, when applying uplink control channel format 1b to the retransmission control signal, the user terminal selects an uplink control channel resource, to which the retransmission control signal is allocated, using following equation 1:

9. The radio communication method according to claim 2, wherein, when applying uplink control channel format 3 to the retransmission control signal, the user terminal allocates the retransmission control signal to a predetermined uplink control channel resource that is designated by an ARI included in the downlink control information, from among a plurality of resources that are reported by higher layer signaling.

10. The radio communication method according to claim 2, wherein uplink control channel format 1b is applied to a retransmission control signal for a downlink data signal of the first cell.

6. A radio communication system comprising a radio base station and a user terminal that adopt carrier aggregation between a first cell and a second cell and that communicate by way of time division duplexing, wherein the user terminal comprises:

a receiving section that receives downlink control information for the first cell and the second cell respectively, allocated to a downlink control channel of the first cell, by adopting cross-carrier scheduling;

a determining section that determines retransmission control for downlink data signals transmitted through each cell; and

a feedback control section that generates retransmission control signals for each downlink data signal in predetermined uplink control channel formats, allocates the generated retransmission control signals to a resource of an uplink control channel of the first cell and sends feedback to the radio base station,

wherein, when a ratio of downlink subframes is higher in the second cell than in the first cell, the feedback control section applies uplink control channel format 3 to a retransmission control signal for a downlink data signal of the second cell demodulated by using downlink control information in which an index number of a channel control element is equal to or lower than a predetermined value, and applies uplink control channel format 1b to a retransmission control signal for a downlink data signal of the second cell demodulated by using downlink control information in which an index number of a channel control element is greater than the predetermined value.

7. A user terminal that adopts carrier aggregation between a first cell and a second cell and that communicates with a radio base station by way of time division duplexing, the user terminal comprising:

a receiving section that receives downlink control information for the first cell and the second cell respectively, allocated to a downlink control channel of the first cell, by adopting cross-carrier scheduling;

a determining section that deter mines retransmission control for downlink data signals transmitted through each cell; and

a feedback control section that generates retransmission control signals for each downlink data signal in predetermined uplink control channel formats, allocates the generated retransmission control signals to a resource of an uplink control channel of the first cell and sends feedback to the radio base station,

wherein, when a ratio of downlink subframes is higher in the second cell than in the first cell, the feedback control section applies uplink control channel format 3 to a retransmission control signal for a downlink data signal of the second cell demodulated by using downlink control information in which an index number of a channel control element is equal to or lower than a predetermined value, and applies uplink control channel format 1b to a retransmission control signal for a downlink data signal of the second cell demodulated by using downlink control information in which an index number of a channel control element is greater than the predetermined value.