Telecommunications – Radiotelephone system – Zoned or cellular telephone system
Reexamination Certificate
1999-11-12
2001-12-11
Chang, Vivian (Department: 2682)
Telecommunications
Radiotelephone system
Zoned or cellular telephone system
C455S446000, C455S067150
Reexamination Certificate
active
06330439
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a method for predicting radio-wave propagation loss as in a radio network planning system; and, more particularly, to a method for predicting radio-wave propagation loss values of points located along radial lines of a cell grid map and points missed out of the radial lines by using an improved interpolation scheme.
DESCRIPTION OF THE PRIOR ART
Generally, a radio network planning system determines a cell coverage of a base station in order to predict radio-wave propagation losses and plan a radio network. The term “cell coverage” means a service area of the base station. As a radio wave signal is far from the base station transmitting the radio wave signal to a terminal, the intensity of the radio wave signal becomes gradually weaken. When the intensity of the radio wave signal is less than a predetermined intensity, a communication between mobile and base stations becomes impossible. Further, in case where the terrain, nature features on the earth and so on influence the radio wave signal, the shape of the cell coverage is irregular on the cell grid map. To predict the cell coverage of the base station, a radio network planning system may calculate radio-wave propagation loss values by using a mathematical model and geographic information
A conventional radio-wave propagation prediction engine of the radio network planning system calculates the radio-wave propagation loss values from the origin of the base station to the predetermined radius and stores data representing the calculated radio-wave propagation losses.
The radio-wave propagation prediction engine reads parameters related to a predetermined radius and a form of data of the radio-wave propagation losses. Then, the radio-wave propagation prediction engine calls the mathematical model to calculate the radio-wave propagation losses. The radio-wave propagation prediction engine stores data of the calculated radio-wave propagation losses according to the data form. Typically, information of a grid form as a radio-wave propagation prediction result is stored in the radio network planning system, wherein the information of the grid form may satisfy a given resolution.
An algorithm for predicting the radio-wave propagation losses is implemented in a conventional radio network planning system. The algorithm performs a radio-wave propagation loss prediction of points located along with a plurality of radial lines of a cell grid map while increasing an angle of a radial line. The radial lines are extended from the base station to a point of a circumference in the cell grid map, respectively. The radio network planning system converts data of a spherical coordinate to data of a rectangular coordinate in order to save the calculated values. At this time, some points may be missed out of the radial lines of the cell grid map and in the calculation of radio-wave propagation losses. For the sake of reducing the number of the missed points, the number of the radial lines should be increased in the cell grid map.
When the number of radial lines is increased in the cell grid map, there is a problem that the number of calculations should be increased. Although an interpolation scheme has been employed to reduce the number of calculations, there is a problem that the conventional interpolation scheme can not effectively reduce the number of calculations according to data randomly defined by a user.
SUMMARY OF THE INVENTION
It is, therefore, an object of the present invention to provide a method for predicting radio-wave propagation loss values of points located along radial lines of a cell grid map and points missed out of the radial lines that is capable of controlling the number of calculations according to data defined by a user and improving the accuracy of the radio-wave propagation loss prediction by using an improved interpolation scheme.
It is, therefore, another object of the present invention to provide a computer-readable medium that performs a method for predicting radio-wave propagation losses of points located along radial lines of a cell grid map and points missed out of the radial lines by using an improved interpolation scheme.
In accordance with one aspect of the present invention, there is provided a method for predicting radio-wave propagation loss values of points located in a service area of a base station, wherein the service area is represented by a circle about the base station mapped into a cell grid map and wherein the points includes radial points located on radial lines and missed points out of the radial lines, comprising the steps of: (a) calculating radio-wave propagation loss values of points located along with initial and next radial lines based on parameters defined by a user; (b) designating one of initial missed points as a target point, wherein the initial missed points are located within a region of the cell grid map defined by the initial and next radial lines and a circumference of the circle connected between the initial and next radial lines; (c) searching first and second mapping points, wherein the first mapping point is located on an intersection point of a perpendicular line and the initial radial line and the second mapping point is located on an intersection point of a perpendicular line and the next radial line; (d) calculating radio-wave propagation loss values of the first and second mapping points; (e) calculating radio-wave propagation loss value of the target point by using the radio-wave propagation loss values of the first and second mapping points; (f) designating another initial missed point as the target point and repeating said steps (c) to (f) until radio-wave propagation loss values for all the initial missed points are calculated; and (g) designating the next radial line as an initial line and repeating said steps (a) to (g) to calculate the radio-wave propagation loss values of the radial points located on the radial lines and the missed points out of the radial lines.
In accordance with another aspect of the present invention, there is provided a computer-readable medium for predicting radio-wave propagation loss values of points located in a service area of a base station, wherein the service area is represented by a circle about the base station mapped into a cell grid map and wherein the points includes radial points located on radial lines and missed points out of the radial lines, comprising the steps of: (a) calculating radio wave propagation loss values of points located along with initial and next radial lines based on parameters defined by a user; (b) designating one of initial missed points as a target point, wherein the initial missed points are located within a region of the cell grid map defined by the initial and next radial lines and a circumference of the circle connected between the initial and next radial lines; (c) searching first and second mapping points, wherein the first mapping point is located on an intersection point of a perpendicular line and the initial radial line and the second mapping point is located on an intersection point of a perpendicular line and the next radial line; (d) calculating radio-wave propagation loss values of the first and second mapping points; (e) calculating radio-wave propagation loss value of the target point by using the radio-wave propagation loss values of the first and second mapping points; (f) designating another initial missed point as the target point and repeating said steps (c) to (f) until radio-wave propagation loss values for all the initial missed points are calculated; and (g) designating the next radial line as an initial line and repeating said steps (a) to (g) to calculate the radio-wave propagation loss values of the radial points located on the radial lines and the missed points out of the radial lines.
REFERENCES:
patent: 5301127 (1994-04-01), Hitney
patent: 5579053 (1996-11-01), Pandel
patent: 5878328 (1999-03-01), Chawla et al.
patent: 6108011 (2000-08-01), Fowler
Jung Hyun-Meen
Shin Young-Hee
Chang Vivian
Korea & Telecom
Nguyen Duc
Staas & Halsey , LLP
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