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

• US 20140133434A1
• Filed: 07/13/2012
• Published: 05/15/2014
• Est. Priority Date: 07/15/2011
• Status: Active Grant

• Current Assignee: NTT Docomo Incorporated (Nippon Telegraph and Telephone Corporation)
• Original Assignee: NTT Docomo Incorporated (Nippon Telegraph and Telephone Corporation)
• Inventors: Takeda, Kazuaki, Abe, Tetsushi, Kishiyama, Yoshihisa, Nagata, Satoshi, Nishikawa, Daisuke
• Granted Patent: US 9,716,578 B2
• Time in Patent Office: Days
• US Class Current: 370/329
• CPC Class Codes: H04B 7/0452 Multi-user MIMO systems
• CPC Class Codes: H04L 5/0007 the frequencies being orthogonal, e.g. OFDM(A), DMT
• CPC Class Codes: H04L 5/0053 Allocation of signaling, i.e. of overhead other than pilot signals
• CPC Class Codes: H04W 72/23 in the downlink direction of a wireless link, i.e. towards a terminal

Abstract

The present invention is designed to minimize the increase of user terminal power consumption even when downlink control channels are extended. A radio base station apparatus having: an allocation section that allocates downlink control information in a first control region from a top of a radio frame to a predetermined OFDM symbol and in a second control region that is frequency-divided with a data region in a region that is time-divided with the first control region, and also allocates decoding control information that indicates a user terminal to perform a decoding process for the second control region, in the first control region; and a transmission section that transmits the downlink control information and the decoding control information; and a user terminal having: a receiving section that receives the downlink control information and the decoding control information from the radio base station apparatus; and a decoding section that controls the decoding process for the second control region based on the decoding control information received, are provided.

Claims

1. A radio communication system comprising:

a radio base station apparatus comprising;

an allocation section that allocates downlink control information in a first control region from a top of a radio frame to a predetermined OFDM symbol and in a second control region that is frequency-divided with a data region in a region that is time-divided with the first control region, and also allocates decoding control information that indicates a user terminal to perform a decoding process for the second control region, in the first control region; and

a transmission section that transmits the downlink control information and the decoding control information; and

a user terminal comprising;

a receiving section that receives the downlink control information and the decoding control information from the radio base station apparatus; and

a decoding section that controls a decoding process for the second control region based on the decoding control information received.

2. The radio communication system according to claim 1, wherein the decoding control information is set in a common search space of a downlink control channel of the first control region.

3. The radio communication system according to claim 2, wherein:

in the decoding control information, an index number to identify a user terminal and bit information are defined in association; and

the user terminal determines whether or not to perform the decoding process for the second control region based on the bit information that corresponds to an index number reported by a higher layer signal.

4. The radio communication system according to claim 3, wherein a same index number is shared between a plurality of user terminals.

5. The radio communication system according to claim 3, wherein the bit information includes information related to a modulation scheme or a rank, in addition to the decoding control information.

6. The radio communication system according to claim 1, wherein a size of a format of the decoding control information is a same size as a format of DCI having an uplink scheduling grant to be allocated in the first control region as content and/or DCI having a downlink scheduling assignment as content.

7. The radio communication system according to claim 1, wherein the downlink control information that is allocated in the first control region and the second control region is an uplink scheduling grant to control an uplink data channel and/or a downlink scheduling assignment to control a downlink data channel.

8. A radio base station apparatus comprising:

an allocation section that allocates downlink control information in a first control region from a top of a radio frame to a predetermined OFDM symbol and in a second control region that is frequency-divided with a data region in a region that is time-divided with the first control region, and also allocates decoding control information that indicates a user terminal to perform a decoding process for the second control region, in the first control region; and

a transmission section that transmits the downlink control information and the decoding control information to a user terminal.

9. A user terminal comprising:

a receiving section that receives downlink control information that is allocated in a first control region from a top of a radio frame to a predetermined OFDM symbol and in a second control region that is frequency-divided with a data region in a region that is time-divided with the first control region, and also receives decoding control information that is allocated in the first control region and that indicates a user terminal to perform a decoding process for the second control region; and

a decoding section that control the decoding process for the second control region based on the decoding control information.

10. A radio communication method of transmitting downlink control information generated in a radio base station apparatus to a user terminal and controlling demodulation of the downlink control information received in the user terminal, the method comprising the steps in which:

the radio base station apparatus;

allocates downlink control information in a first control region from a top of a radio frame to a predetermined OFDM symbol and in a second control region that is frequency-divided with a data region in a region that is time-divided with the first control region, and also allocates decoding control information that indicates a user terminal to perform a decoding process for the second control region, in the first control region; and

transmits the downlink control information and the decoding control information; and

the user terminal;

receives the downlink control information and the decoding control information from the radio base station apparatus; and

controls the decoding process for the second control region based on the decoding control information received.

11. A radio communication system comprising:

a radio base station apparatus comprising;

an allocation section that allocates, over continuous radio frames, downlink control information in a first control region from a top of each radio frame to a predetermined OFDM symbol, and also allocates, in a specific radio frame, downlink control information in a second control region that is frequency-divided with a data region in a region that is time-divided with the first control region; and

a transmission section that transmits the downlink control information allocated in the first control region and the second control region; and

a user terminal comprising;

a receiving section that receives the downlink control information from the radio base station apparatus; and

a decoding section that decodes the downlink control information of the first control region and the second control region received.

12. The radio communication system according to claim 11, wherein, to a plurality of user terminals in a same cell, information to indicate the specific radio frame where the downlink control information is allocated in the second control region is separately reported by higher layer signals.

13. The radio communication system according to claim 11, wherein, to a plurality of user terminals in the same cell, information to indicate the specific radio frame where the downlink control information is allocated in the second control region is reported by a broadcast signal from the radio base station.

14. A radio base station apparatus comprising:

an allocation section that allocates downlink control information in a first control region from a top of each radio frame to a predetermined OFDM symbol, over continuous radio frames, and also allocates, in a specific radio frame, downlink control information in a second control region that is frequency-divided with a data region in a region that is time-divided with the first control region; and

a transmission section that transmits the downlink control information allocated in the first control region and the second control region to a user terminal.

15. A user terminal comprising:

a receiving section that receives downlink control information that is allocated, in a first control region from a top of each radio frame to a predetermined OFDM symbol, over continuous radio frames, and downlink control information that is allocated in a second control region that is frequency-divided with a data region in a region that is time-divided with the first control region, in a specific radio frame; and

a decoding section that decodes downlink control information of the first control region and the second control region received.

16. A radio communication method of transmitting downlink control information generated in a radio base station apparatus to a user terminal and controlling demodulation of the downlink control information received in the user terminal, the method comprising the steps in which:

the radio base station apparatus;

allocates downlink control information in a first control region from a top of each radio frame to a predetermined OFDM symbol, over continuous radio frames, and also allocates, in a specific radio frame, downlink control information in a second control region that is frequency-divided with a data region in a region that is time-divided with the first control region; and

transmits the downlink control information allocated in the first control region and the second control region; and

the user terminal;

receives the downlink control information from the radio base station apparatus; and

decodes the downlink control information of the first control region and the second control region received.