WIRELESS LOCAL AREA NETWORK TEST SYSTEM WITH FORCED TRANSMIT RATES DURING PROTOCOL-BASED TESTING

• US 20110103235A1
• Filed: 10/27/2010
• Published: 05/05/2011
• Est. Priority Date: 10/30/2009
• Status: Active Grant

• Current Assignee: Apple Inc.
• Original Assignee: Apple Inc.
• Inventors: Luong, Anh, Gregg, Justin
• Granted Patent: US 8,731,493 B2
• Time in Patent Office: Days
• US Class Current: 370/245
• CPC Class Codes: H04L 43/024 by adaptive sampling
• CPC Class Codes: H04L 43/16 Threshold monitoring
• CPC Class Codes: H04L 43/18 Protocol analysers
• CPC Class Codes: H04W 24/06 Testing, supervising or monitoring using simulated traffic
• CPC Class Codes: H04W 84/12 WLAN [Wireless Local Area Networks]

Abstract

A system for performing wireless local area network testing of wireless devices may include a wireless local area network tester and a device under test. The tester and device under test may communicate over a wireless link. To ensure that the tester accurately analyzes test data, a data rate table is used that specifies fixed data transmission rates to be used by the device under test under both high-quality link conditions and low-quality link conditions. This forces the device under test to transmit control packets at the same high data rate during packet loopback testing, regardless of link quality. When the captured control packets are analyzed at the tester, both low-link-quality data and high-link-quality data may be analyzed using a common test template, ensuring accurate results.

Claims

1. A method for performing wireless tests on a device under test using a wireless local area network tester that wirelessly communicates with the device under test over a wireless link, comprising:

when the wireless link has a first quality, capturing a first set of ACK codes in the wireless local area network tester that have been transmitted from the device under test at a given data rate;

when the wireless link has a second quality that is lower than the first quality, capturing a second set of ACK codes in the wireless local area network tester that have been transmitted from the device under test at the given data rate; and

analyzing the captured first and second sets of ACK codes with a common test template in the wireless local area network tester.

2. The method defined in claim 1 wherein the given data rate comprises 54 Mbps and wherein analyzing the captured first and second sets of ACK codes comprises analyzing the captured first and second sets of ACK codes with a 54 Mbps test template in the wireless local area network tester.

3. The method defined in claim 2 wherein the device under test uses a data rate table that directs the second set of ACK codes to be transmitted from the device under test to the wireless local area network tester at the given data rate even when the second quality is substantially lower than the first quality and wherein capturing the second set of ACK codes comprises:

capturing the second set of ACK codes in the wireless local area network tester that have been transmitted from the device under test at the given data rate as directed by the data rate table.

4. The method defined in claim 1 wherein during normal operation of the device under test in a wireless network having a wireless network link of the second quality, data is transmitted at a reduced data rate that is lower than the given data rate and wherein capturing the second set of ACK codes comprises capturing data that has been transmitted from the device under test at the given data rate that is greater than the reduced data rate.

5. The method defined in claim 4 wherein analyzing the captured first and second sets of ACK codes comprises extracting transmit power values for the device under test.

6. The method defined in claim 4 wherein analyzing the captured first and second sets of ACK codes comprises extracting error vector magnitude values.

7. The method defined in claim 1 wherein analyzing the captured first and second sets of ACK codes comprises extracting transmit power values for the device under test.

8. The method defined in claim 1 wherein analyzing the captured first and second sets of ACK codes comprises extracting error vector magnitude values.

9. The method defined in claim 1 further comprising:

with the wireless local area network tester, transmitting Internet Control Message Protocol pings to the device under test at the given data rate.

10. The method defined in claim 1 further comprising:

performing an association process between the wireless local area network tester and the device under test at the given data rate.

11. The method defined in claim 1 wherein the first and second sets of ACK codes are transmitted by the device under test using a common frequency modulation scheme and wherein capturing the first set of ACK codes and capturing the second set of ACK codes comprises:

capturing the first set of ACK codes transmitted using the common frequency modulation scheme; and

capturing the second set of ACK codes transmitted using the common frequency modulation scheme.

12. The method defined in claim 11 wherein the first and second sets of ACK codes are transmitted by the device under test using a common frame size and wherein capturing the first set of ACK codes and capturing the second set of ACK codes comprises:

capturing the first set of ACK codes transmitted using the common frame size; and

capturing the second set of ACK codes transmitted using the common frame size.

13. The method defined in claim 1 wherein the first and second sets of ACK codes are transmitted by the device under test using a common frame size and wherein capturing the first set of ACK codes and capturing the second set of ACK codes comprises:

capturing the first set of ACK codes transmitted using the common frame size; and

capturing the second set of ACK codes transmitted using the common frame size.

14. The method defined in claim 13 wherein the first and second sets of ACK codes are transmitted by the device under test using a common error coding scheme and wherein capturing the first set of ACK codes and capturing the second set of ACK codes comprises:

capturing the first set of ACK codes transmitted using the common error coding scheme; and

capturing the second set of ACK codes transmitted using the common error coding scheme.

15. The method defined in claim 14 wherein the first and second sets of ACK codes are transmitted by the device under test using a common frequency modulation scheme and wherein capturing the first set of ACK codes and capturing the second set of ACK codes comprises:

capturing the first set of ACK codes transmitted using the common frequency modulation scheme; and

capturing the second set of ACK codes transmitted using the common frequency modulation scheme.

16. The method defined in claim 1 wherein the first and second sets of ACK codes are transmitted by the device under test using a common error coding scheme and wherein capturing the first set of ACK codes and capturing the second set of ACK codes comprises:

capturing the first set of ACK codes transmitted using the common error coding scheme; and

capturing the second set of ACK codes transmitted using the common error coding scheme.

17. A method for performing wireless packet loopback tests on a device under test using a tester that wirelessly communicates with the device under test over a wireless link, comprising:

when the wireless link has a first quality, capturing a first set of codes in the tester that have been transmitted from the device under test at a given data rate; and

when the wireless link has a second quality that is lower than the first quality, capturing a second set of codes in the tester that have been transmitted from the device under test at the given data rate.

18. The method for performing wireless packet loopback tests defined in claim 17 further comprising:

analyzing the captured first and second sets of codes with a common test profile in the tester.

19. A method for performing wireless packet loopback tests on a device under test using a tester that wirelessly communicates with the device under test over a wireless link, wherein during normal operation of the device under test, the device under test transmits data with a first frame size when communicating over a link of a first quality and transmits data with a second frame size that is different from the first frame size when communicating over a link of a second quality that is lower than the first quality, the method comprising:

when the wireless link between the tester and the device under test has the first quality, capturing a first set of codes in the tester that have been transmitted from the device under test with the first frame size; and

when the wireless link between the tester and the device under test has the second quality, capturing a second set of codes in the tester that have been transmitted from the device under test with the first frame size.

20. The method for performing wireless packet loopback tests defined in claim 19 wherein the first and second codes comprise ACK codes, the method further comprising:

analyzing the captured first and second sets of codes with a common test template in the tester.