Method and apparatus for base station and mobile station time calibration

• US 7,039,098 B2
• Filed: 08/03/2001
• Issued: 05/02/2006
• Est. Priority Date: 08/07/2000
• Status: Expired due to Term

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Younis, Saed
• Primary Examiner(s): Chin, Stephen
• Assistant Examiner(s): Wang, Ted M.
• Application Number:
  US09/923,001
• Publication Number:
  US 20020085627A1
• Time in Patent Office: 1,733 Days
• Field of Search: 375/149, 375/211, 375/150, 375/147, 375/145, 375/141, 375/148, 370/335, 370/350, 370/441, 455/456.2, 455/130, 455/440, 455/456.1, 455/456.5, 455/502, 455/67.16, 455/457, 342/387, 342/357.03, 342/363
• US Class Current: 375/149
• CPC Class Codes: H04B 7/2681 Synchronisation of a mobile station with one base station
• CPC Class Codes: H04B 7/2693 Centralised synchronisation, i.e. using external universal time reference, e.g. by using a global positioning system [GPS] or by distributing time reference over the wireline network

Abstract

A method and apparatus for calibrating a Base Station and Mobile Station for use in systems that use round trip delay and systems that do not use round trip delay.

Claims

1. A method for determining an amount of delay between a base station and a transmission antenna of the base station, comprising:

determining locations of a reception antenna and the transmission antenna to determine an air time between the reception and transmission antennas;

determining a transmission time by calculating a time it takes for a signal transmitted from the base station through the transmission antenna to arrive at the reception antenna; and

determining the amount of delay between the base station and the transmission antenna by subtracting the air time from the transmission time; and

offsetting a relative timing of the signal transmitted from the base station with respect to a reference signal at a point of generation of the signal transmitted from the base station to determine a timing at the transmission antenna of the signal transmitted from the base station with respect to the reference signal.

2. The method of claim 1, wherein the location of the reception antenna is determined by using a GPS position location system.

3. The method of claim 1 wherein offsetting a relative timing of the signal transmitted from the base station with respect to a reference signal comprises:

determining the relative timing of a pilot signal transmitted by the base station with respect to a timing reference signal, comprising;

generating a reference CDMA pilot signal on the same carrier frequency on which the pilot signal is generated by the base station, the reference CDMA pilot signal having a known timing relationship to the timing reference signal;

locking the frequency of the reference CDMA pilot signal and the timing reference signal to a common frequency reference;

combining the reference CDMA pilot signal the pilot signal generated by the base station; and

determining the time offset between the reference CDMA pilot signal and the pilot signal generated by the base station.

4. The method of claim 3, wherein the timing difference between the reference CDMA pilot signal and the pilot signal generated by the base station is determined using a mobile device having a pilot searcher.

5. The method of claim 3, wherein the reference CDMA pilot signal is generated by a base station simulator.

6. The method of claim 3, wherein the timing reference signal is a signal indicating the GPS time clock 1 PPS tick.

7. The method of claim 3, wherein the common frequency reference is a 10 MHz output from a GPS receiver.

8. The method of claim 3, wherein the timing reference signal is generated by the GPS receiver.

9. The method of claim 3, wherein the combining of the reference CDMA pilot signal and the pilot signal generated by the base station is an RF combining.

10. The method of claim 1 wherein offsetting a relative timing of the signal transmitted from the base station with respect to a reference signal comprises:

determining the relative timing of a pilot signal with respect to a timing reference signal, the pilot signal being generated by the base station and transmitted through a transmission antenna, comprising;

receiving the pilot signal generated by the base station in a pilot signal receiver having an antenna, the transmission delay between the antenna of the receiver and the transmission antenna of the base station being known;

storing the received pilot signal;

calibrating the delay from the antenna of the receiver to a digitizing converter;

triggering the reception and storage of the pilot signal with a signal based upon a known timing relationship with the timing reference signal; and

processing the stored data to determine the relationship between the received signal and the timing reference signal.

11. The method of claim 10, wherein the received pilot signal is digitized prior to being stored.

12. The method of claim 10, wherein the timing reference signal is a signal indicating the GPS time clock 1 PPS tick.

13. The method of claim 12, wherein the reception and storage of the received signal is triggered at a known time with respect to the GPS time clock 1 PPS tick.

14. The method of claim 12, wherein the reception and storage of the received signal is triggered at the GPS time clock 1 PPS tick.