BASESTATION FOR CELLULAR COMMUNICATION SYSTEM

• US 20100216408A1
• Filed: 05/05/2010
• Published: 08/26/2010
• Est. Priority Date: 08/29/2006
• Status: Active Grant

• Current Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Original Assignee: Ubiquisys Limited (Cisco Systems, Inc.)
• Inventors: Whittaker, Stephen, Carter, Alan
• Granted Patent: US 8,041,393 B2
• Time in Patent Office: Days
• US Class Current: 455/67.110
• CPC Class Codes: H01Q 1/246 specially adapted for base stations
• CPC Class Codes: H03J 7/02 Automatic frequency control H03J7/18 takes precedence

Abstract

A basestation in a cellular communication system corrects frequency errors in signals generated within the basestation. The frequency errors may be corrected on the basis of signals transmitted by one or more other basestations within the network. As an alternative, the basestation may request information from one or more mobile devices that are also able to detect transmissions from other basestations.

Claims

1. A method for controlling operation of an oscillator in a basestation of a cellular communications system, the method comprising:

requesting a mobile device to report a first measurement of a time difference between frames transmitted from the basestation and another basestation;

requesting the mobile device to report a second measurement of the time difference between frames transmitted from the basestation and the other basestation;

based on said reported first and second measurements, estimating a frequency offset between a signal generated within said basestation and a corresponding signal generated within said other basestation; and

controlling operation of said oscillator based on said estimated frequency offset.

2. A method as claimed in claim 1, wherein said first and second measurements of time differences are SFN-SFN measurements.

3. A method as claimed in claim 1, wherein the step of estimating the frequency offset comprises:

determining a difference between the reported first and second measurements;

determining from said difference, an amount of difference that accumulates in a predetermined time period; and

estimating said frequency offset therefrom.