Method and apparatus for multipath signal detection, identification, and monitoring for wideband code division multiple access systems

• US 7,110,725 B2
• Filed: 03/12/2002
• Issued: 09/19/2006
• Est. Priority Date: 03/12/2001
• Status: Expired due to Term

• Current Assignee: Amazon Technologies, Inc. (Amazon.com, Inc.)
• Original Assignee: Skyworks Solutions Incorporated
• Inventors: Kent, Mark
• Primary Examiner(s): LE, DANH C
• Application Number:
  US10/096,429
• Publication Number:
  US 20020127987A1
• Time in Patent Office: 1,652 Days
• Field of Search: 455/343, 455/38.3, 455/574, 455/343.5, 455/343.4, 455/208, 455/502, 455/75, 455/78, 455/255, 455/258, 370/311, 370/354, 370/151, 370/144, 370/335, 370/350, 370/331, 340/7.32, 340/7.37, 375/354
• US Class Current: 455/85
• CPC Class Codes: H04W 52/029 reducing the clock frequency of the controller
• CPC Class Codes: Y02D 30/70 in wireless communication networks

Abstract

Methods to generate a mobile time reference are provided. A representative method includes providing a high frequency clock, providing a low frequency clock, generating a mobile time reference using the high frequency clock, maintaining the mobile time reference using the low frequency clock when the high frequency clock is turned off, and continuing to generate the mobile time reference using the high frequency clock when the high frequency clock has been turned back on. Systems and other methods are also provided.

Claims

1. A method of providing a mobile time reference in a portable transceiver system, comprising:

providing a high frequency clock;

providing a low frequency clock;

generating a mobile time reference using the high frequency clock;

updating at least twice the mobile time reference using the low frequency clock when the high frequency clock is not available; and

continuing to generate the mobile time reference using the high frequency clock when the high frequency clock is available,

wherein updating the mobile time reference includes counting cycles of the low frequency clock and adding in a drifting estimate.

2. The method of claim 1, wherein the mobile time reference includes at least one of a clock-phase, a chip-counter, a slot-counter, and a frame-counter.

3. The method of claim 1, wherein the high frequency clock is generated by a temperature controlled crystal oscillator.

4. The method of claim 1, wherein the high frequency clock provides a signal of at least 30 MHz.

5. The method of claim 1, wherein the mobile time reference has an accuracy of at least 32 nanoseconds.

6. The method of claim 1, wherein the low frequency clock is generated by a crystal oscillator.

7. The method of claim 1, wherein the low frequency clock provides a 32 KHz signal.

8. The method of claim 1, farther comprising estimating the drift of the low frequency clock.

9. A portable transceiver system comprising:

an antenna;

a radio frequency subsystem coupled to the antenna and including a high frequency oscillator and a low frequency oscillator; and

a baseband subsystem coupled to the radio frequency system and including a free running counter coupled to the high frequency oscillator and the low frequency oscillator,

the free running counter providing a mobile time reference to the system and having an active mode and an idle mode, during the active mode the free running counter uses the high frequency oscillator to generate the mobile time reference, and during the idle mode the free running counter uses the low frequency oscillator to update at least twice the mobile time reference,

wherein the baseband subsystem includes a multi-path signal recovery circuit and the mobile time reference is provided to the multipath signal recovery circuit.

10. The system of claim 9, wherein the high frequency oscillator is a temperature controlled crystal oscillator.

11. The system of claim 9, wherein the low frequency oscillator is a crystal oscillator.

12. The system of claim 11, wherein the crystal oscillator provides a 32 KHz clock.

13. The system of claim 9, wherein the baseband subsystem includes a multipath monitor and the mobile time reference is provided to the multipath monitor.

14. The system of claim 9, wherein the mobile time reference is constantly available.

15. The system of claim 9, wherein the mobile time reference has an accuracy of at least 32 nanoseconds.

16. The system of claim 9, wherein the free running counter includes a phase locked loop coupling the low frequency oscillator to the high frequency oscillator.

17. The system of claim 9, wherein the free running counter includes a drift estimator for the low frequency oscillator.

18. A portable transceiver system comprising:

an antenna;

a radio frequency subsystem coupled to the antenna and including a high frequency oscillator and a low frequency oscillator; and

a baseband subsystem coupled to the radio frequency system and including a means for providing a free running counter coupled to the high frequency oscillator and the low frequency oscillator,

the means for providing a free running counter further including means for providing a mobile time reference to the system and having an active mode and an idle mode, during the active mode the means for providing a mobile time reference uses the high frequency oscillator to generate the mobile time reference, and during the idle mode the means for providing a mobile time reference uses the low frequency oscillator to update at least twice the mobile time reference, the means for providing a mobile time reference comprising means for counting the cycles of the low frequency clock and means for adding in a drift estimate of the low frequency clock.