Method for identifying a fast speed mobile station, and a base station

• US 6,259,919 B1
• Filed: 02/14/1997
• Issued: 07/10/2001
• Est. Priority Date: 06/16/1995
• Status: Expired due to Term

• Current Assignee: Nokia Technologies Oy (Nokia Corporation)
• Original Assignee: Nokia Telecommunications Oy (Nokia Corporation)
• Inventors: Inkinen, Kullervo, Suonvieri, Jukka
• Primary Examiner(s): Eisenzopf, Reinhard J.
• Assistant Examiner(s): Bhattacharya, Sam
• Application Number:
  US08/793,495
• Time in Patent Office: 1,607 Days
• Field of Search: 455/422, 455/436, 455/437, 455/438, 455/439, 455/441, 455/444, 455/449, 455/450, 455/517, 455/524, 455/429, 375/341, 375/346
• US Class Current: 455/441
• CPC Class Codes: G01S 11/10 using Doppler effect
• CPC Class Codes: H04W 36/32 by location or mobility data, e.g. speed data
• CPC Class Codes: H04W 36/324 by mobility data, e.g. speed data

Abstract

A method for identifying a fast speed mobile station (MS) in a radio system, said method comprising measuring the frequency error of radio signals received from a mobile station. In order for a fast speed mobile station to be more reliably identified than before, the method comprises calculating the change (df) in BSC the frequency error from a time interval (t) of predetermined length, and identifying the mobile station as a fast speed mobile station if the change (df) in the calculated frequency error exceeds a predetermined limit value.

Claims

1. A method for identifying a fast speed mobile station in a radio system, said method comprising:

continuously measuring, at a base station, a frequency error of radio signals received from a mobile station;

calculating, at said base station, a change in said frequency error from a time interval of predetermined length;

identifying said mobile station as a fast speed mobile station if said change in said calculated frequency error exceeds a predetermined limit value; and

transmitting, from said base station, a speed report concerning said mobile station to a base station controller, only when said mobile station has been identified as a fast speed mobile station.

2. A method according to claim 1, wherein said change in said frequency error is calculated by calculating a first average frequency error during a first time interval, and thereafter a second average frequency error during a second time interval, and finally an absolute value of a difference between said first average frequency error and said second average frequency error.

3. A base station of a radio system, said base station comprising:

a receiver arranged to receive signals transmitted by a mobile station;

means for continuously measuring a frequency error of said received signals;

a calculator unit responsive to said measuring means and arranged to calculate a change in said frequency error in a time interval of predetermined length;

a comparator responsive to said calculator unit and arranged to compare said change in said frequency error with a predetermined limit value and to identify said mobile station as a fast speed mobile station if said change in said frequency error exceeds said predetermined limit value; and

means responsive to said comparator for sending a speed report concerning said mobile station to a base station controller only when said comparator of said base station identifies said mobile station as a fast speed mobile station.

4. A base station according to claim 3, wherein said calculator unit is arranged to calculate a first average of said frequency error based on measuring results obtained during a first time interval, a second average of said frequency error based on measuring results obtained during a second time interval, and an absolute value of a difference between said first and said second average of said frequency error to determine said change in said frequency error.

5. A base station according to claim 3, wherein said base station comprises means for adjusting a length of said time interval and said predetermined limit value to correspond to a set value given by an operator.

6. A base station according to claim 3, wherein said base station comprises means for sending said speed report to said base station controller in connection with signalling associated with call maintenance.

7. A base station according to claim 3, wherein said base station is a base station of a GSM system, and said base station is arranged to transmit said speed report to said base station controller in connection with measurement reporting defined in GSM Specification 08.58.

8. A base station according to claim 3, wherein said speed report contains at least a speed class of said mobile station.

9. A base station according to claim 7, wherein said speed report contains at least a speed class of said mobile station.

10. A method for identifying a fast speed mobile station in a radio system, said method comprising:

defining predetermined speed classes;

continuously measuring, at a base station, a frequency error of radio signals received from a mobile station;

calculating, at said base station, a change in said frequency error from a time interval of predetermined length;

identifying said mobile station as a fast speed mobile station if said change in said calculated frequency error exceeds a predetermined limit value; and

identifying a speed class corresponding to said calculated change in said frequency error;

transmitting, from said base station, a speed report concerning said mobile station to a base station controller, only when said mobile station has been identified as a fast speed mobile station, said speed report including at least said speed class of said mobile station.

11. A base station of a radio system, said base station comprising:

a receiver arranged to receive signals transmitted by a mobile station;

means for continuously measuring a frequency error of said received signals;

a calculator unit responsive to said measuring means and arranged to calculate a change in said frequency error in a time interval of predetermined length;

a comparator responsive to said calculator unit and arranged to compare said change in said frequency error with a predetermined limit value and to identify said mobile station as a fast speed mobile station if said change in said frequency error exceeds said predetermined limit value;

means for identifying a predetermined speed class corresponding to said change in said frequency error; and

means responsive to said comparator for sending a speed report concerning said mobile station to a base station controller only in response to an identification of said mobile station as a fast speed mobile station.

12. A base station of a radio system, said base station comprising:

a receiver arranged to receive signals transmitted by a mobile station;

a measuring mechanism to continuously measure a frequency error of said received signals;

a calculator unit responsive to said measuring mechanism and arranged to calculate a change in said frequency error in a time interval of predetermined length;

a comparator responsive to said calculator unit and arranged to compare said change in said frequency error with a predetermined limit value and to identify said mobile station as a fast speed mobile station if said change in said frequency error exceeds said predetermined limit value; and

a sending mechanism, responsive to said comparator, to send a speed report concerning said mobile station to a base station controller only when said comparator of said base station identifies said mobile station as a fast speed mobile station.

13. A base station of a radio system, said base station comprising:

a receiver arranged to receive signals transmitted by a mobile station;

a measuring mechanism to continuously measure a frequency error of said received signals;

a calculator unit responsive to said measuring mechanism and arranged to calculate a change in said frequency error in a time interval of predetermined length;

a comparator responsive to said calculator unit and arranged to compare said change in said frequency error with a predetermined limit value and to identify said mobile station as a fast speed mobile station if said change in said frequency error exceeds said predetermined limit value;

an identifying mechanism to identify a predetermined speed class corresponding to said change in said frequency error; and

a sending mechanism responsive to said comparator to send a speed report concerning said mobile station to a base station controller only in response to an identification of said mobile station as a fast speed mobile station.