RADIO BASE STATION AND RADIO COMMUNICATION METHOD

• US 20140293950A1
• Filed: 11/22/2012
• Published: 10/02/2014
• Est. Priority Date: 11/25/2011
• Status: Active Grant

• Current Assignee: NTT Docomo Incorporated (Nippon Telegraph and Telephone Corporation)
• Original Assignee: NTT Docomo Incorporated (Nippon Telegraph and Telephone Corporation)
• Inventors: Benjebbour, Anass
• Granted Patent: US 9,374,812 B2
• Time in Patent Office: Days
• US Class Current: 370/329
• CPC Class Codes: H04W 16/32 Hierarchical cell structures
• CPC Class Codes: H04W 52/0206 in access points, e.g. base stations access point devices per se H04W88/08
• CPC Class Codes: H04W 72/23 in the downlink direction of a wireless link, i.e. towards a terminal
• CPC Class Codes: H04W 84/045 using private Base Stations, e.g. femto Base Stations, home Node B
• CPC Class Codes: Y02D 30/70 in wireless communication networks

Abstract

To provide a radio communication method when a macro-base station and micro-base station are regarded as a plurality of transmission points and the plurality of transmission points performs downlink communications using a plurality of carriers, in the radio communication method of the invention, a macro-base station (10) forming a macro-cell determines whether or not a micro-base station transmits a non-data signal that is at least one of a synchronization signal, broadcast signal, measurement reference signal and downlink control signal using a capacity carrier (ST102), and transmits instruction information for instructing the micro-base station (20) to start transmission of the non-data signal using the capacity carrier to the micro-base station when it is determined that the micro-base station transmits the non-data signal (ST103), and the micro-base station (20) starts transmission of the non-data signal using the capacity carrier based on the instruction information from the macro-base station (10) (ST104).

Claims

1. A radio base station forming a macro-cell to transmit a downlink signal including a data signal using a first carrier where a micro-base station that transmits a data signal using a second carrier associated with the first carrier is disposed in the macro-cell, comprising:

a determination section that determines whether or not the micro-base station transmits a non-data signal that is at least one of a synchronization signal, a broadcast signal, a measurement reference signal and a downlink control signal using the second carrier; and

a transmission section that transmits instruction information for instructing the micro-base station to start transmission of the non-data signal using the second carrier to the micro-base station when the determination section determines that the micro-base station transmits the non-data signal.

2. The radio base station according to claim 1, further comprising:

a traffic information acquiring section that acquires traffic information indicating whether or not the micro-base station transmits at least a part of the data signal transmitted in the macro-cell,

wherein the determination section determines whether or not the micro-base station transmits the non-data signal, based on the traffic information acquired in the traffic information acquiring section.

3. The radio base station according to claim 2, wherein the traffic information is reception signal quality from the micro-base station in a user terminal reported from the user terminal, and when the reception signal quality is a predetermined threshold or more, the determination section determines that the micro-base station transmits the non-data signal.

4. The radio base station according to claim 2, wherein the traffic information is position information of a user terminal, and when the position information of the user terminal indicates inside the micro-cell, the determination section determines that the micro-base station transmits the non-data signal.

5. The radio base station according to claim 1, wherein the determination section determines whether or not the micro-base station transmits the non-data signal periodically, and when the determination section determines that the micro-base station transmits the non-data signal periodically, the instruction information includes a transmission interval of the non-data signal and transmission start timing.

6. The radio base station according to claim 1, wherein the determination section determines whether or not the micro-base station transmits the non-data signal non-periodically, and when the determination section determines that the micro-base station transmits the non-data signal non-periodically, the instruction information includes bit information for instructing a transmission start of the non-data signal.

7. The radio base station according to claim 1, wherein the determination section determines whether or not the micro-base station halts transmission of the non-data signal using the second carrier, and when it is determined that the micro-base station halts transmission of the non-data signal, the transmission section transmits instruction information for instructing the micro-base station to halt transmission of the non-data signal using the second carrier to the micro-base station.

8. The radio base station according to claim 1, wherein the determination section determines whether or not to change a transmission interval of the non-data signal from the micro-base station using the second carrier, and when it is determined that the transmission interval of the non-data signal from the micro-base station is changed, the transmission section transmits instruction information for instructing the micro-base station to change the transmission interval of the non-data signal using the second carrier to the micro-base station.

9. The radio base station according to claim 1, wherein the transmission section transmits the instruction information to the micro-base station via a cable interface.

10. The radio base station according to claim 1, wherein the transmission section transmits the instruction information to the micro-base station via a radio link.

11. The radio base station according to claim 10, wherein the transmission section transmits the instruction information as a part of control information transmitted on a downlink control channel of the first carrier.

12. The radio base station according to claim 9, wherein the transmission section transmits the instruction information by higher layer signaling.

13. A radio base station that is disposed in a macro-cell to transmit a downlink signal using a first carrier and that transmits a data signal using a second carrier associated with the first carrier, comprising:

a reception section that receives, from a macro-base station forming the macro-cell, instruction information for instructing the micro-base station to start transmission of a non-data signal that is at least one of a synchronization signal, a broadcast signal, a measurement reference signal and a downlink control signal using the second carrier; and

a transmission section that starts transmission of the non-data signal using the second carrier based on the received instruction information.

14. The radio base station according to claim 13, wherein the reception section receives instruction information for instructing the micro-base station to halt transmission of the non-data using the second carrier from the macro-base station, and based on the received instruction information, the transmission section halts transmission of the non-data signal using the second carrier.

15. The radio base station according to claim 13, wherein the reception section receives instruction information for instructing the micro-base station to change a transmission interval of the non-data signal using the second carrier from the micro-base station, and based on the received instruction information, the transmission section changes the transmission interval of the non-data signal using the second carrier.

16. A radio communication method in which a micro-base station that is disposed in a macro-cell to transmit a downlink signal using a first carrier transmits a data signal using a second carrier associated with the first carrier, comprising:

in a macro-base station forming the macro-cell, determining whether or not the micro-base station transmits a non-data signal that is at least one of a synchronization signal, a broadcast signal, a measurement reference signal and a downlink control signal using the second carrier;

in the macro-base station, transmitting instruction information for instructing the micro-base station to start transmission of the non-data signal using the second carrier to the micro-base station when it is determined that the micro-base station transmits the non-data signal; and

in the micro-base station, starting transmission of the non-data signal using the second carrier based on the instruction information from the macro-base station.