Method for decision of time delay by repeater in mobile communication network

• US 7,400,890 B2
• Filed: 08/11/2004
• Issued: 07/15/2008
• Est. Priority Date: 10/31/2003
• Status: Active Grant

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Lee, Young-Sik
• Primary Examiner(s): Phu; Sanh D.
• Application Number:
  US10/915,747
• Publication Number:
  US 20050096066A1
• Time in Patent Office: 1,434 Days
• Field of Search: 455/456.1, 455/11.1, 455/456.5, 342/464
• US Class Current: 455/456.1
• CPC Class Codes: G01S 19/06 employing an initial estimate of the location of the receiver as aiding data or in generating aiding data
• CPC Class Codes: G01S 19/252 Employing an initial estimate of location in generating assistance data
• CPC Class Codes: G01S 5/0244 Accuracy or reliability of position solution or of measurements contributing thereto

Abstract

A method for determination of a repeater time delay in a mobile communication network, without affecting a correct positioning of a mobile terminal, is disclosed. The method includes the steps of determining an initial estimated position of a mobile communication terminal to be measured its position, estimating a respective distance between a serving base station and an adjacent base station and the mobile terminal using the initial estimated position, estimating a time difference of arrival of a serving base station signal and an adjacent base station signal received by the mobile terminal using the estimated distances, receiving the time difference of arrival of the serving base station signal and the adjacent base station signal measured from the mobile terminal, calculating a difference between the estimated time difference of arrival and the measured time difference of arrival, and determining the difference as a repeater time delay existing in the serving base station of the mobile terminal, if said difference is larger than a predetermined threshold value. The present invention makes it possible to estimate in advance the clock error in the terminal owing to the repeater time delay in AGPS system, so it can provide the terminal with more precise Acquisition Assistance Information (AAI). Further, such estimation of clock errors in the mobile terminal makes it possible to prevent the failure in acquisition of GPS signals that may occur due to the significant deflection error in the clock operation of the mobile terminal.

Claims

1. A method for determining a repeater time delay of a base station in a mobile communication network, comprising the steps of:

(i) estimating an arrival time difference in a serving base station signal and an adjacent base station signal of a mobile communication terminal to be measured its position, and then calculating a time delay caused by a repeater in the serving base station using the estimated arrival time difference and a measured arrival time difference in the serving base station signal and the adjacent base station signal measured by the mobile communication terminal; and

(ii) if a resultant value of a difference between the measured time difference of arrival and the estimated time difference of arrival, plus the calculated time delay by the serving base station repeater is larger than a predetermined first threshold value, then determining the resultant value as a repeater time delay of the associated adjacent base station.

2. The method according to claim 1, wherein step (i) further comprises the steps of:

(a) determining an initial estimated position of a mobile communication terminal whose position is to be measured;

(b) estimating a respective distance between a serving base station and an adjacent base station and the mobile terminal using the initial estimated position;

(c) estimating a time difference of arrival of a serving base station signal and an adjacent base station signal received by the mobile terminal using the estimated distances;

(d) receiving the time difference of arrival of the serving base station signal and the adjacent base station signal, actually measured from the mobile terminal;

(e) calculating a difference between the estimated time difference of arrival and the measured time difference of arrival; and

(f) determining the difference as a repeater time delay existing in the serving base station of the mobile terminal, if said difference is larger than a predetermined second threshold value.

3. The method according to claim 2, wherein step (a) further comprises the step of determining a coordinate value of a sector center position in the serving base station as the initial estimated position.

4. The method according to claim 2, wherein step (a) further comprises the step of determining as the initial estimated position an average coordinate value of the sector center positions in a plurality of serving base stations that can be received by the mobile terminal.

5. The method according to claim 2, wherein step (a) further comprises the step of determining an average value of coordinates of the base stations that can be received by the mobile terminal as the initial estimated position.

6. The method according to claim 2, wherein step (a) further comprises the step of determining the initial estimated position using pilot phase difference of the base stations received by the mobile terminal.

7. The method according to claim 2, wherein step (a) further comprises the step of determining the initial estimated position using either one of a round trip delay (RTD) and a round trip time (RTT) and the pilot signal of the serving base station received by the mobile terminal.

8. The method according to claim 2, wherein step (b) further comprises the step of estimating a distance between the mobile terminal and the serving base station using the initial estimated position of the mobile terminal and a positional coordinate of the serving base station, and estimating a distance between the mobile terminal and the adjacent base station using the initial estimated position of the mobile terminal and a positional coordinate of the adjacent base station.

9. The method according to claim 2, wherein said second threshold value is set to the maximum value of time difference of arrival errors in the serving base station signal and the adjacent base station signal actually measured by the mobile terminal.

10. The method according to claim 2, wherein said first threshold value and said second threshold value are identical to each other.

11. The method according to claim 2, wherein said first threshold value is larger than said second threshold value.

12. The method according to claim 2, wherein said first threshold value is not larger than said second threshold value.

13. The method according to claim 1, wherein step (i) further comprises a step of determining that no repeater time delay exists in the serving base station of the mobile terminal in case that the difference is not larger than said second threshold value.