Mobile communication system, base station, cell coverage control method

• US 8,879,400 B2
• Filed: 09/10/2012
• Issued: 11/04/2014
• Est. Priority Date: 03/17/2010
• Status: Expired due to Fees

• Current Assignee: Fujitsu Limited
• Original Assignee: Fujitsu Limited
• Inventors: Koike, Hitoshi, Nakahara, Tohru, Ogawa, Koji
• Primary Examiner(s): Harper, Kevin C
• Application Number:
  US13/608,006
• Publication Number:
  US 20120327909A1
• Time in Patent Office: 785 Days
• Field of Search: None
• US Class Current: 370/241
• 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 a base station and mobile stations:

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

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 deviation of the first distance from a prescribed target distance.

2. The mobile communication system according to claim 1, 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 a time of handover start of the mobile station and a second position and a second value of reception power of the reference signal at a time of handover completion of the mobile station.

3. The mobile communication system according to claim 1, 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.

4. The mobile communication system according to claim 1, 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.

16. The mobile communication system according to claim 1, wherein the base station controls a tilt angle of antenna so as to minimize the deviation of the first distance from a prescribed target distance.

5. A mobile communication system comprising a base station and mobile stations:

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

wherein the base station obtains a measured cell coverage as a 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,

wherein the base station specifies a 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 a position of the mobile station.

6. A base station comprising:

a transmission unit that transmits a reference signal to mobile stations;

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

a cell coverage measurement unit that estimates a first distance from the base station as reference 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 transmission power to the mobile station so as to minimize deviation of the first distance from a prescribed target distance.

7. The base station according to claim 6, 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 a time of handover start of the mobile station and a second position and a second value of reception power of the reference signal at a time of handover completion of the mobile station.

8. The base station according to claim 6, 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.

9. The base station according to claim 6, 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.

17. The base station according to claim 6, wherein the cell coverage control unit controls a tilt angle of antenna so as to minimize the deviation of the first distance from the prescribed target distance.

10. A base station comprising:

a transmission unit that transmits a reference signal to mobile stations;

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

a cell coverage measurement unit that obtains 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 station; and

a cell coverage control unit that 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,

wherein the cell coverage measurement unit specifies a 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 a position of the mobile station.

11. 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 a mobile station position information of the mobile station and a value of reception power of a reference signal from the base station;

estimating by the base station a first distance from the base station as a reference of cell coverage based on the position information and the value of reception power from the mobile station; and

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

12. The control method of controlling cell coverage according to claim 11, wherein the estimating by the base station includes estimating the first distance based on a first position and a first value of reception power of the reference signal at a time of handover start of the mobile station and a second position and a second value of reception power of the reference signal at a time of handover completion of the mobile station.

13. The control method of controlling cell coverage according to claim 11, wherein the estimating by the base station 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.

14. The control method of controlling cell coverage according to claim 11, further including selecting by the base station 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 11, wherein the controlling by the base station comprises controlling by the base station a tilt angle of antenna so as to minimize the deviation of the first distance from the prescribed target distance.

15. 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 a mobile station position information of the mobile station and a value of reception power of a reference signal from the base station;

obtaining by the base station 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 station; and

controlling by the base station at least one of a plurality of 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,

wherein the obtaining by the base station of the measured cell coverage includes specifying by the base station a 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 a position of the mobile station.