Real-time transceiver gain and path loss calibration for wireless systems

• US 6,272,322 B1
• Filed: 02/04/2000
• Issued: 08/07/2001
• Est. Priority Date: 02/04/2000
• Status: Expired due to Term

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Atheros Communications Incorporated (Qualcomm, Inc.)
• Inventors: Su, David
• Primary Examiner(s): Chang, Vivian
• Assistant Examiner(s): MEHRPOUR, NAGHMEH
• Application Number:
  US09/498,400
• Time in Patent Office: 550 Days
• Field of Search: 455/67.1, 455/67.4, 455/67.6, 455/552, 455/69, 379/22.01
• US Class Current: 455/67.14
• CPC Class Codes: H04B 17/10 of transmitters
• CPC Class Codes: H04B 17/309 Measuring or estimating channel quality parameters
• CPC Class Codes: H04W 52/24 using SIR [Signal to Interference Ratio] or other wireless path parameters

Abstract

A calibration method and apparatus are described. In one embodiment, the method includes a pair of transceivers performing a loop back test to determine a relationship between transmit and receive gain for each transceiver. A path loss between the first transceiver and a second transceiver is computed. The computation is made by transmitting a pair of signals in opposite directions between the first and second transceivers to determine a relationship between transmit path gain of the first transceiver and receive path gain of the second transceiver and a relationship between the transmit path gain of the second transceiver and receive path of the first transceiver. The transmit and receive path gains are generated for the first transceivers based on the path loss and the relationship.

Claims

1. A calibration method comprising:

a pair of transceivers performing a loop back test to determine a relationship between transmit and receive gain for each transceiver;

computing a path loss between a first transceiver and a second transceiver, wherein computing the path loss comprises transmitting a pair of signals in opposite directions between the first and second transceivers to determine a relationship between transmit path gain of the first transceiver and receive path gain of the second transceiver and a relationship between the transmit path gain of the second transceiver and receive path gain of the first transceiver; and

generating transmit and receive path gains for the first transceivers based on the path loss and the relationships.

2. The method defined in claim 1 wherein performing the loop back test comprises using an attenuation in a transmit path of the first transceiver.

3. The method defined in claim 1 wherein the loop back test comprises de-activating any step attenuators in transmit and received paths of the first transceiver.

4. The method defined in claim 1 wherein generating the transmit and receive path gains for the first transceiver comprises performing power level calibration using a fixed power level.

5. The method defined in claim 1 further comprising calibrating step attenuators in the first and second transceivers.

6. The method defined in claim 5 wherein calibrating step attenuators comprises performing a loop back test while activating each step attenuator for each transceiver transmit or receive path when only activating said each step attenuator during the loop back test.

7. The method defined in claim 1 further comprising adjusting an output power level for each transmitter based on its path loss and its transmit path and receive path gains.

8. The method defined in claim 1 further comprising adding a third transceiver mode comprising:

(a) the third transceiver performing a loop back test;

(b) a base station transmitting a signal to the third transceiver;

(c) the third transceiver transmitting a signal to the base station;

(d) determining transmit and receive path gains and third transceiver attenuation based on results of (a)-(c).

9. A calibration method using a plurality of mobile unit that each have a transceiver, the method comprising:

each transceiver performing a loop back test to determine relationships between transmitter and receiver power levels of each transceiver;

computing path loss between a pair of transceivers, wherein computing path loss includes each transceiver transmitting a signal to another transceiver;

determining the receive path gain for each transceiver based on the computed path loss and the power level of a signal received by said each transceiver and transmitted by another transceiver using a predetermined transmit power level; and

determining the transmit path gains and another receive path gain based on the first receive path gain.

10. The method defined in claim 9 wherein calibrating step attenuators for the transceivers by performing a loop back test for each step attenuator in during which only said each step attenuator is active.

11. The method defined in claim 9 wherein adjusting an output power level for each transmitter based on its path loss and its transmit and receive gains.

12. The method defined in claim 9 further comprising adding a third transceiver mode comprising:

(e) the third transceiver performing a loop back test;

(f) a base station transmitting a signal to the third transceiver;

(g) the third transceiver transmitting a signal to the base station;

(h) determining transmit and receive path gains and third transceiver attenuation based on results of (a)-(c).

13. An apparatus comprising:

means in each of a pair of transceivers for performing a loop back text to determine a relationship between transmit and receive gain for each transceiver; and

means for computing a path loss between the first transceiver and a second transceiver by transmitting a pair of signals in opposite directions between the first and second transceivers to determine a relationship between transmit path gain of the first transceiver and receive path gain of the second transceiver and a relationship between the transmit path gain of the second transceiver and receive path of the first transceiver; and

means for generating transmit and receive path gains for the first transceivers based on the path loss and the relationships.

14. The apparatus defined in claim 13 wherein the means for performing the loop back test comprise means for providing attenuation in a transmit path of the first transceiver.

15. The apparatus defined in claim 13 wherein the means for performing loop back test comprises means for de-activating any step attenuators in transmit and received paths of the first transceiver.

16. The apparatus defined in claim 13 wherein the means for generating the transmit and receive path gains for the first transceiver comprises means for performing power level calculation.

17. The apparatus defined in claim 13 further comprising means for calibrating step attenuators in the first and second transceivers.

18. The apparatus defined in claim 17 wherein means for calibrating step attenuators comprises means for performing a loop back test for each step attenuator for each transceiver transmit or receive path when only activating said each step attenuator during the loop back test.

19. The apparatus defined in claim 13 further comprising means for adjusting an output power level for each transmitter based on its path loss and its transmit and receive gains.

20. The apparatus defined in claim 13 further comprising means for adding a third transceiver mode comprising:

means for performing a loop back test in the third transceiver;

means for receiving a signal form a base station;

means for transmitting a signal to the base station;

means for determining transmit and receive path gains and third transceiver attenuation based on the results.

21. A mobile device having a first transceiver the device comprising:

an Rf front end;

a processing unit coupled to the RF front end, the processing circuit performing gain and power level calibration by;

performing a loop back test to determine a relationship between transmit and receive gain for each transceiver; and

computing a path loss between the first transceiver and a second transceiver, wherein computing the loss comprises transmitting a pair of signals in opposite directions between the first and second transceivers to determine a relationship between transmit path gain of the first transceiver and receive path gain of the second transceiver and a relationship between the transmit path gain of the second transceiver and receive path of the first transceiver; and

generating transmit and receive path gains for the first transceivers based on the path loss and the relationship using a fixed power level.