SYSTEM AND METHOD FOR TESTING WIRELESS POSITION LOCATING

• US 20130021912A1
• Filed: 07/22/2011
• Published: 01/24/2013
• Est. Priority Date: 07/22/2011
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Curticapean, Florean, Finlow-Bates, Keir
• Granted Patent: US 8,638,671 B2
• Time in Patent Office: Days
• US Class Current: 370/241
• CPC Class Codes: G01S 5/021 Calibration, monitoring or correction G01S5/0252 takes precedence

Abstract

The present application describes a system and method for testing the position locating and navigation technology of a wireless client. To simulate the locations of the wireless access points in the array that are visible to the wireless client from the simulated location, the round-trip time between the wireless client and a wireless access point can be modified by delaying a response signal from the wireless access point in response to a signal received from the wireless client. The wireless client, knowing the location of the wireless access point and the expected response time of the wireless access point, interprets the delay in the response of the wireless access point as proportional to the distance of the wireless access point from the simulated location of the wireless client.

Claims

1. A method for testing the position locating technology of a wireless client, the method comprising:

selecting a test scenario for a wireless client, the test scenario comprising at least one simulated location of the wireless client and at least one wireless access point visible to the wireless client from the simulated location of the wireless client;

identifying an expected response creation time for the at least one wireless access point visible to the wireless client;

emulating the at least one wireless access point visible to the wireless client and simulating a distance between the simulated location of the wireless client and the location of the at least one wireless access point using an adjusted response creation time for the at least one wireless access point;

executing the test scenario using the expected response creation time and the adjusted response creation time for the at least one wireless access point to test the position locating technology of the wireless device.

2. The method of claim 1, wherein calculating an adjusted response creation time for the at least one wireless access point further comprises:

identifying a distance between the simulated location of the wireless client and the location of the at least one wireless access point;

calculating a simulated propagation delay for the at least one wireless access point, the simulated propagation delay to equal the distance between the simulated location of the wireless client and the location of the at least one wireless access point, divided by the speed of light; and

calculating the adjusted response creation time for the at least one wireless access point as equal to the sum of the expected response creation time of the at least one wireless access point and the simulated propagation delay for the at least one wireless access point.

3. The method of claim 1, wherein executing the test scenario with the wireless client further comprises:

transmitting a packet from the wireless client to the at least one wireless access point;

receiving the packet at the at least one wireless access point;

transmitting a response packet from the at least one wireless access point to the wireless client using the adjusted response creation of the at least one wireless access point by delaying the transmission of the response packet for a time equal to the adjusted response creation time;

receiving the response packet at the wireless client;

determining a round-trip time for the packet;

calculating an estimated distance from the simulated location of the wireless client to the location of the at least one wireless access point using the round-trip time for the packet and the expected response creation time for the at least one wireless access point, wherein the estimated distance is equal to one half of the round-trip time minus the expected response creation time; and

calculating an estimate of the simulated location of the wireless client using the estimated distance from the simulated location of the wireless client to the location of the at least one wireless access point and the location of the at least one wireless access point to test the position locating technology of the wireless client.

4. The method of claim 3, wherein determining the round-trip time for the packet further comprises:

identifying a start time when the packet is sent from the wireless client;

identifying a stop time when the response packet is received at the wireless client; and

determining the round-trip time as the difference between the start time and the stop time.

5. The method of claim 1, wherein the test scenario further comprises a simulated testing period and a plurality of simulated locations of the wireless client, the simulated location of the wireless client adjusted to each of the plurality of simulated locations during the simulated testing period of the test scenario.

6. The method of claim 1, wherein the test scenario further comprises an adjustable signal attenuation setting for the at least one wireless access point.

7. The method of claim 1, wherein the test scenario further comprises an adjustable transmit power setting for the at least one wireless access point.

8. The method of claim 1, wherein the at least one wireless access point further comprises an array of wireless access points.

9. The method of claim 1, wherein identifying a simulated location for the at least one wireless access point visible to the wireless client and an expected response creation time for the at least one wireless access point visible to the wireless client further comprises, identifying the simulated location of the at least one wireless access point and the expected response creation time for the at least one wireless access point from a wireless access point database.

10. The method of claim 1, wherein identifying an expected response creation time for the at least one wireless access point further comprises, receiving the expected response creation time from the at least one wireless access point.

11. The method of claim 1, wherein selecting a test scenario for a wireless client further comprises, receiving input from a Global Navigation Satellite System (GNSS).

12. The method of claim 1, wherein the test scenario further comprises a simulated testing period and wherein selecting a test scenario for a wireless client further comprises identifying an elapsed time into the simulated testing period.

13. The method of claim 1, wherein the test scenario further comprises a simulated multipath environment scenario and wherein the adjusted response creation time further comprises a plurality of adjusted response creation times to simulate a multipath environment.

15. The test system of claim 13, wherein the at least one wireless access point further comprises an array of wireless access points.

16. The test system of claim 13, wherein the test controller further comprises:

a test scenario database comprising a plurality of test scenarios, wherein each test scenario includes at least one simulated location of the wireless client and the location of the at least one wireless access point visible to the wireless client from the simulated location of the wireless client;

a test run controller to select a test scenario from the test scenario database;

a position calculation engine to calculate the adjusted response creation time for the at least one wireless access point; and

a wireless access point database comprising the location for the at least one wireless point visible to the wireless client from the simulated location of the wireless client and an expected response creation time for the at least one wireless access point visible to the wireless client.

17. The test system of claim 15, wherein the test scenario database further comprises a simulated testing period and a plurality of simulated locations of the wireless client, the simulated location of the wireless client adjusted to each of the plurality of simulated locations during the simulated testing period of the test scenario.

18. The test system of claim 15, further comprising an attenuation controller coupled to an output of the at least one wireless access point and to the test scenario database, wherein the test scenario database provides an adjustable signal attenuation setting for the at least one wireless access point.

19. The test system of claim 15, further comprising a Global Navigation Satellite System (GNSS) to provide input to the test run controller in selecting the test scenario.

21. The logic circuit of claim 19, wherein the logic circuit is a Field Programmable Gate Array (FPGA).

14. A test system for testing the position locating technology of a wireless client, the test system comprising:

a high frequency clock;

a test run controller;

at least one wireless access point to receive a control input from the test run controller and a clock input from the high frequency clock, the at least one wireless access point to emulate at least one wireless access point visible to a wireless client at a simulated location and to simulate a distance between the simulated location of the wireless client and the location of the at least one wireless access point using an adjusted response creation time for the at least one wireless access point; and

an access point database to provide an expected response creation time and the location of the at least one wireless access point to the wireless client.

20. A logic circuit comprising:

a wireless access point logic circuit having an expected response creation time; and

a delay circuit to adjust the expected response creation time of the wireless access point logic circuit to simulate a distance of the wireless access point logic circuit from a wireless client.