Methods and apparatuses for measuring frequencies of basestations in cellular networks using mobile GPS receivers

• US 7,024,215 B2
• Filed: 07/21/2005
• Issued: 04/04/2006
• Est. Priority Date: 04/15/2002
• Status: Expired due to Term

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Krasner, Norman F.
• Primary Examiner(s): Eng, George
• Assistant Examiner(s): Stein, Julie E.
• Application Number:
  US11/187,175
• Publication Number:
  US 20050255859A1
• Time in Patent Office: 257 Days
• Field of Search: 455/502, 455/456.1, 342/357.1, 370/350, 370/503
• US Class Current: 455/502
• CPC Class Codes: H04B 7/2675 Frequency synchronisation
• 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
• CPC Class Codes: H04W 56/0035 detecting errors in frequency or phase
• CPC Class Codes: H04W 92/10 between terminal device and access point, i.e. wireless air interface
• CPC Class Codes: H04W 92/20 between access points

Abstract

Methods and systems for frequency synchronizing base stations in a cellular communication system. In one aspect of the invention, a method to measure a frequency related to a base station of a cellular communication system includes receiving a satellite positioning system signal; determining a frequency of a reference signal from a local oscillator of a mobile station from the satellite position system signal; receiving a first cellular signal from a base station containing first and second timing markers; determining first and second time tags for the markers using the reference signal; and combining the frequency of the reference signal and the first and second time tags to compute a first frequency related to the base station.

Claims

1. A method to measure a frequency related to a basestation of a cellular communication system, the method comprising:

receiving, at a mobile station, at least one satellite positioning system signal;

determining a frequency of a reference signal from a local oscillator of the mobile station from the at least one satellite positioning system signal;

receiving, at the mobile station, a first cellular signal from the basestation, the first cellular signal containing a first timing marker and a second timing marker;

determining a first time tag for the first timing marker and a second time tag for the second timing marker, using the reference signal from the local oscillator; and

combining the frequency of the reference signal from the local oscillator with the first and second time tags to compute a first frequency related to the basestation.

2. A method as in claim 1 further comprising:

transmitting, through a communication link, the first frequency to a server.

3. A method as in claim 1 wherein said combining further comprises:

computing a time difference between the time tags.

4. A method as in claim 1 wherein the first frequency is related to a carrier frequency of a signal from the basestation.

5. A method as in claim 1 wherein the first frequency is related to a symbol rate of a signal from the basestation.

6. A system to measure a frequency related to a basestation, the system comprising:

a mobile station comprising;

a cellular transceiver configured to receive from the basestation a cellular signal containing a first timing marker and a second timing marker;

a local oscillator generating a reference signal;

a satellite positioning system receiver coupled to the local oscillator, the satellite positioning system receiver configured to receive at least one satellite positioning system signal and to determine a frequency of the reference signal from the at least one satellite positioning system signal; and

a processor coupled to the cellular receiver and the satellite positioning system receiver, the processor configured to determine a first time tag for the first timing marker and a second time tag for the second timing marker using the reference signal and to combine the frequency of the reference signal with the first and second time tags to compute a first frequency related to the basestation.

7. A system as in claim 6 wherein the satellite positioning system receiver is configured to determine location and velocity data of the mobile station using the at least one satellite positioning system signal.

8. A system as in claim 6 further comprising:

a server coupled to the mobile station through a communication link, the mobile station transmitting through the communication link the first frequency to the server using the cellular transceiver.

9. A system as in claim 6 wherein the satellite positioning system receiver and the cellular transceiver share at least one common component.