RADIO COMMUNICATION SYSTEM, RADIO BASE STATION, AND COMMUNICATION CONTROL METHOD

• US 20130136074A1
• Filed: 04/05/2011
• Published: 05/30/2013
• Est. Priority Date: 04/06/2010
• Status: Active Grant

• Current Assignee: Kyocera Corporation
• Original Assignee: Kyocera Corporation
• Inventors: Okino, Kenta
• Granted Patent: US 9,736,827 B2
• Time in Patent Office: Days
• US Class Current: 370/329
• CPC Class Codes: H04W 24/00 Supervisory, monitoring or testing arrangements
• CPC Class Codes: H04W 52/244 Interferences in heterogeneous networks, e.g. among macro and femto or pico cells or other sector / system interference [OSI]
• CPC Class Codes: H04W 72/00 Local resource management
• CPC Class Codes: H04W 72/23 in the downlink direction of a wireless link, i.e. towards a terminal
• CPC Class Codes: H04W 88/08 Access point devices
• CPC Class Codes: H04W 92/20 between access points

Abstract

A picocell base station (PeNB) uses a downlink control channel, the frequency band of which overlaps with the frequency band of the downlink control channel used by a macrocell base station (MeNB), to transmit downlink control information for controlling radio communication with a radio terminal (PUE) connected to the picocell base station (PeNB). The picocell base station (PeNB) comprises an X2 interface communication unit (140) which uses inter-base station communication to transmit to the macrocell base station (MeNB) usage control information for controlling the control channel usage that is the usage of a radio resource used as the downlink control channel by the macrocell base station (MeNB).

Claims

1. A radio communication system, comprising:

a first radio base station configured to control radio communications with a radio terminal connecting with the first radio base station by using a downlink control channel; and

a second radio base station which is a neighboring radio base station of the first radio base station and is configured to control radio communications with a radio terminal connecting with the second radio base station by using a downlink control channel having a frequency band overlapping with a frequency band of the downlink control channel used by the first radio base station, wherein

the first radio base station includes a transmitter configured to send the second radio base station control information for controlling a usage state of the downlink control channel of the second radio base station, and

the second radio base station includes;

a receiver configured to receive the control information from the first radio base station; and

a controller configured to control the usage state of the downlink control channel of the second radio base station according to the control information received by the receiver.

2. The radio communication system according to claim 1, wherein the usage state is a control channel usage indicating an amount of radio resource used as the downlink control channel.

3. The radio communication system according to claim 2, wherein the control information contains information indicating a limitation target subframe which is a subframe in which the control channel usage of the first radio base station or the second radio base station is to be limited to an upper limit value or below.

4. The radio communication system according to claim 3, wherein the control information contains information indicating the upper limit value.

5. The radio communication system according to claim 3, wherein the control information contains information on whether to make linked-control of a data channel usage indicating an amount of radio resource used as a downlink data channel according to the control channel usage in the limitation target subframe.

6. The radio communication system according to claim 3, wherein the control information contains information indicating that the first radio base station limits downlink transmission power of all frequency bands in a data region in the limitation target subframe to a threshold or below, and information indicating the threshold.

7. The radio communication system according to claim 1, wherein the control information contains

symbol number information indicating the number of symbols corresponding to a time range, which are used by the first radio base station as the downlink control channel within a subframe, and

usage rate information indicating a usage rate of radio resource, which is an upper limit for the second radio base station within the time range.

8. The radio communication system according to claim 1, wherein the control information contains

symbol number information indicating the number of symbols corresponding to a time range, which are used by the first radio base station as the downlink control channel within a subframe, and

usage rate information indicating a usage rate of radio resource, which is an upper limit for the first radio base station within the time range.

9. The radio communication system according to claim 7, a wherein the controller of the second radio base station controls the radio resource usage rate of the second radio base station within the time range according to the symbol number information and the usage rate information which are contained in the control information received by the receiver.

10. The radio communication system according to claim 1, wherein the usage state is transmission power of the downlink control channel.

11. A radio base station configured to control radio communications with a radio terminal connecting with the radio base station by using a downlink control channel having a frequency band overlapping with a frequency band of a downlink control channel used by a neighboring base station, comprising:

a transmitter configured to send the neighboring base station control information for controlling a usage state of the downlink control channel of the neighboring base station.

12. A radio base station configured to control radio communications with a radio terminal connecting with the radio base station by using a downlink control channel having a frequency band overlapping with a frequency band of a downlink control channel used by a neighboring base station, comprising:

a receiver configured to receive the control information for controlling a usage state of the downlink control channel of the radio base station, and

a controller configured to control the usage state of the downlink control channel of the radio base station according to the control information received by the receiver.

13. A communication control method used in a radio communication system comprising:

a first radio base station configured to control radio communications with a radio terminal connecting with the first radio base station by using a downlink control channel; and

a second radio base station which is a neighboring radio base station of the first radio base station and is configured to control radio communications with a radio terminal connecting with the second radio base station by using a downlink control channel having a frequency band overlapping with a frequency band of the downlink control channel used by the first radio base station, the communication control method comprising the steps of;

sending control information for controlling a usage state of the downlink control channel of the second radio base station from the first radio base station to the second radio base station;

receiving by the second radio base station the control information from the first radio base station; and

controlling by the second radio base station a usage state of the downlink control channel of the second radio base station according to the control information received at the receiving step.