Mobile telecommunications system and a mobile telecommunications control method

• US 20050037756A1
• Filed: 12/18/2003
• Published: 02/17/2005
• Est. Priority Date: 12/18/2002
• Status: Active Grant

• Current Assignee: Socionext Inc.
• Original Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Inventors: Sato, Shunji, Yaguchi, Yoshiharu
• Granted Patent: US 7,016,691 B2
• Time in Patent Office: Days
• US Class Current: 455/436
• CPC Class Codes: H04W 36/30 by measured or perceived connection quality data
• CPC Class Codes: H04W 36/32 by location or mobility data, e.g. speed data
• CPC Class Codes: Y02D 30/70 in wireless communication networks

Abstract

Regulating the unnecessary handover control count and reducing the power consumption of a radio mobile station thereby reducing the load on an entire radio telecommunications system to maintain stable communications. By adding a position calculator, a direction calculator and a velocity calculator to a radio mobile station and adding the information on a radio base station and the peripheral radio base stations into report information used by the radio base station, handover control considers the position, direction, and velocity as well as the downlink communications quality according to the related art. This regulates the unnecessary handover control count and reduces the load on the entire radio telecommunications system and the power consumption of the radio mobile station.

Claims

1. A mobile telecommunications system comprising:

a plurality of radio base stations; and

a radio mobile station, which communicates with one of the radio base stations via a radio channel;

wherein the radio mobile station comprises;

a position information detector, which detects a current position on the radio mobile station;

a communications quality detector, which detects qualities of downlink communications of the respective radio base stations at the current position;

a distance calculator, which calculates distances from the radio mobile station to the radio base stations at the current position;

a travel direction detector, which detects a travel direction of the radio mobile station at the current position;

a travel velocity detector, which detects a velocity of the radio mobile station at the current position;

a position predictor, which predicts a position of the radio mobile station after an arbitrary time interval is elapsed, based on the travel direction and the velocity;

an information generator, which generates peripheral radio base station information, including the distances from the radio mobile station to respective radio base stations at the predicted position, and downlink communications qualities of respective radio base stations at the predicted position;

handover destination determinant, which determines one radio base station among the base stations as a handover destination, based on the calculated distances to respective radio base stations and downlink communications qualities of respective radio base stations in the peripheral radio base station information; and

handover controller, which performs a handover control with the radio base station determined by the handover destination determiner.

2. The mobile telecommunications system according to claim 1, wherein the position information detector receives positioning information from GPS satellites to calculate the information on its own position.

3. The mobile telecommunications system according to claim 1, wherein the travel direction detector calculates the travel direction of the radio mobile station based on a direction identification sensor and the state of radio communications with a radio base station.

4. The mobile telecommunications system according to claim 1, wherein the travel velocity detector uses the positioning information from GPS satellites and radio communications state information to calculate the velocity of the radio mobile station.

5. The mobile telecommunications system according to claim 1, wherein the radio base station which operable to previously store the position information on the radio base station and position information on the peripheral radio base stations, and

the radio base station comprises:

position information reporter, which reports the position information of the radio base station and the position information of the peripheral radio base stations to the radio mobile station as report information.

6. The mobile telecommunications system according to claim 5, wherein the distance calculator calculate the distance to a peripheral radio base station by using the current position of the radio mobile station detected by the position information detector and the report information from the position information reporter.

7. The mobile telecommunications system according to claim 1, wherein the handover destination determiner compares the distances to the radio base stations in the predicted peripheral radio base station information and the downlink communications qualities of the radio base stations, and determines as one handover destination the radio base station which is the closest to the radio mobile station and which best improves the downlink communications quality.

8. The mobile telecommunications system according to claim 1, wherein the handover controller changes the handover control parameter values based on the peripheral radio base station density calculated from the peripheral radio base station information and performs handover control.

9. The mobile telecommunications system according to claim 1, wherein the handover controller changes the sending power to the radio mobile station based on the peripheral radio base station density calculated from the peripheral radio base station information and performs handover control.

10. A mobile telecommunications control method for the mobile telecommunications system comprising a plurality of radio base stations;

and a radio mobile station, which communicates with one of the radio base stations via a radio channel;

wherein the method comprises the steps of;

predicting the position of the radio mobile station after an arbitrary time interval is elapsed;

calculating the distance to respective radio base stations, travel direction of the radio mobile station, velocity of the radio mobile station and downlink communications quality from respective radio base stations at the predicted position;

determining a radio base station as a handover destination based on the calculated distance to each radio base station, velocity of the radio mobile station and downlink communications quality of each radio base station; and

performing handover control with the determined radio base station as a handover destination.

11. A computer-readable medium in which a mobile telecommunications control program for causing a computer to implement:

a feature to-detect a downlink communications quality in the communications between a radio base station and a radio mobile station;

a feature to detect a current position on the radio mobile station;

a feature to calculate distances from the radio mobile station to the radio base stations at the current position;

a feature to detect a travel direction of the radio mobile station at the current position;

a feature to detect a velocity of the radio mobile station at the current position;

a feature to predict a position of the radio mobile station after an arbitrary time interval is elapsed, based on the travel direction and the velocity;

a feature to generate peripheral radio base station information, including distances to respective radio base stations at the predicted position, and downlink communications qualities of respective radio base station at the predicted position;

a feature to determine one radio base station among the radio base stations as a handover destination based on the calculated distance to respective radio base stations and downlink communications quality of respective radio base stations in the peripheral radio base station information; and

a feature to change the handover control parameter values and sending power to the radio mobile station based on the peripheral radio base station density calculated from the peripheral radio base station information and performs handover control with the determined radio base station as a handover destination.