MOBILE COMMUNICATION SYSTEM, BASE STATION, CELL COVERAGE CONTROL METHOD

• US 20120327909A1
• Filed: 09/10/2012
• Published: 12/27/2012
• Est. Priority Date: 03/17/2010
• Status: Active Grant

• Current Assignee: Fujitsu Limited
• Original Assignee: Fujitsu Limited
• Inventors: Ogawa, Koji, Koike, Hitoshi, Nakahara, Tohru
• Granted Patent: US 8,879,400 B2
• Time in Patent Office: Days
• US Class Current: 370/331
• CPC Class Codes: H04W 16/28 using beam steering
• CPC Class Codes: H04W 24/02 Arrangements for optimising operational condition
• CPC Class Codes: H04W 24/08 Testing, supervising or monitoring using real traffic
• CPC Class Codes: H04W 36/0088 Scheduling hand-off measurements
• CPC Class Codes: H04W 52/245 taking into account received signal strength
• CPC Class Codes: H04W 52/247 where the output power of a terminal is based on a path parameter sent by another terminal
• CPC Class Codes: H04W 52/283 Power depending on the position of the mobile
• CPC Class Codes: H04W 52/40 during macro-diversity or soft handoff

Abstract

There is provided a mobile communication system, a base station, and a method of controlling cell coverage that is capable of operating a mobile communication system such that the cell coverage is maintained approximately and timely at a target level without requiring much labor. In this mobile communication system, a mobile station reports to the base station the position information of the mobile station and the value of reception power of reference signal from the base station. The base station obtains the measured cell coverage as a result of measurement of cell coverage based on the position information and the value of reception power from the mobile stations, and controls at least one of plural parameters including transmission power to the mobile stations, tilt angle of antenna, etc., so as to minimize deviation of the measured cell coverage from the target cell coverage.

Claims

1. A mobile communication system comprising base stations and mobile stations:

wherein the mobile station reports to the base station the position information of the mobile station and the value of reception power of the reference signal from the base station; and

wherein the base station obtains the measured cell coverage as the result of measurement of cell coverage based on the position information and the value of reception power reported from the mobile station, and controls at least one of plural parameters including transmission power to the mobile station, tilt angle of antenna, so as to minimize deviation of the measured cell coverage from a target cell coverage.

2. The mobile communication system according to claim 1, wherein the base station estimates a first distance from the base station as a reference of cell coverage based on the position information and the value of reception power reported from the mobile station, and controls transmission power to the mobile station so as to minimize the deviation of the first distance from a prescribed target distance.

3. The mobile communication system according to claim 2, wherein the base station estimates the first distance based on a first position and a first value of reception power of the reference signal at the time of handover start of the mobile station and a second position and a second value of reception power of the reference signal at the time of handover completion of the mobile station.

4. The mobile communication system according to claim 2, wherein the base station estimates the first distance based on a known third position and a known third value of reception power and a fourth position and a fourth value of reception power of the reference signal of a mobile station judged to be positioned near cell edge.

5. The mobile communication system according to claim 2, wherein the base station selects the shortest first distance from among plural first distances obtained based on the position information and the value of reception power from plural mobile stations.

6. The mobile communication system according to claim 1, wherein the base station specifies the region of the measured cell coverage in prescribed region unit by correlating signal attenuation factor obtained from the value of transmission power of the reference signal and the value of reception power of the reference signal in the mobile station with the position of the mobile station.

7. A base station comprising:

a transmission unit that transmits reference signal to mobile stations;

a reception unit that obtains the position information of a mobile station and the value of reception power of the reference signal in the mobile station from the mobile station;

a cell coverage measurement unit that obtains the measured cell coverage as the result of measurement of cell coverage based on the position information and the value of reception power from the mobile station; and

a cell coverage control unit that controls at least one of plural parameters including the transmission power to the mobile station, tilt angle of antenna so as to minimize the deviation of the measured cell coverage from a target cell coverage.

8. The base station according to claim 7, wherein the cell coverage measurement unit estimates a first distance from the base station as reference of the cell coverage based on the position information and the value of reception power from the mobile station;

and

wherein the cell coverage control unit controls transmission power to the mobile station so as to minimize the deviation of the first distance from a prescribed target distance.

9. The base station according to claim 8, wherein the cell coverage measurement unit estimates the first distance based on a first position and a first value of reception power of the reference signal at the time of handover start of the mobile station and a second position and a second value of reception power of the reference signal at the time of handover completion of the mobile station.

10. The base station according to claim 8, wherein the cell coverage measurement unit estimates the first distance based on a known third position and a known third value of reception power and a fourth position and a fourth value of reception power of the reference signal of a mobile station judged to be positioned near cell edge.

11. The base station according to claim 8, wherein the cell coverage measurement unit selects the shortest first distance from among plural first distances obtained based on the position information and the value of reception power from a plurality of mobile stations.

12. The base station according to claim 7, wherein the cell coverage measurement unit specifies the region of the measured cell coverage in prescribed region unit by correlating signal attenuation factor obtained from the value of transmission power of the reference signal and the value of reception power of the reference signal in the mobile station with the position of the mobile station.

13. A control method of controlling cell coverage for a base station to control cell coverage of the base station in a mobile communication system including the base station and mobile stations, the control method of controlling cell coverage comprising:

reporting to the base station by the mobile station of the position information of the mobile station and the value of reception power of reference signal from the base station;

obtaining by the base station of measured cell coverage as the result of measurement of cell coverage based on the position information and the value of reception power from the mobile stations; and

controlling by the base station of at least one of a plurality of parameters including transmission power to the mobile stations, tilt angle of antenna so as to minimize the deviation of the measured cell coverage from a target cell coverage.

14. The control method of controlling cell coverage according to claim 13, wherein the obtaining by the base station of the measured cell coverage includes estimating by the base station of a first distance from the base station as a reference of the cell coverage based on the position information and the value of reception power from the mobile stations;

and wherein the controlling by the base station includes controlling the transmission power to the mobile stations so as to minimize the deviation of the first distance from a prescribed target distance.

15. The control method of controlling cell coverage according to claim 14, wherein the obtaining by the base station of the measured cell coverage includes estimating by the base station of the first distance based on a first position and a first value of reception power of the reference signal at the time of handover start of the mobile station and a second position and a second value of reception power of the reference signal at the time of handover completion of the mobile station.

16. The control method of controlling cell coverage according to claim 14, wherein the obtaining by the base station of the measured cell coverage includes estimating the first distance based on a known third position and a known third value of reception power and a fourth position and a fourth value of reception power of the reference signal of a mobile station judged to be positioned near cell edge.

17. The control method of controlling cell coverage according to claim 14, further including selecting by the base station of the shortest first distance from among plural first distances obtained based on the position information and the value of reception power from a plurality of mobile stations.

18. The control method of controlling cell coverage according to claim 13, wherein the obtaining by the base station of the measured cell coverage includes specifying by the base station of the region of the measured cell coverage in prescribed region unit by correlating signal attenuation factor obtained from the value of transmission power of the reference signal and the value of reception power of the reference signal in the mobile station with the position of the mobile station.