System for determining RF path loss between an RF source and an RF receiver with hysteresis and related methods

• US 20070207758A1
• Filed: 03/01/2006
• Published: 09/06/2007
• Est. Priority Date: 03/01/2006
• Status: Active Grant

• Current Assignee: Malikie Innovations Limited (Key Patent Innovations Limited)
• Original Assignee: Blackberry Limited
• Inventors: Qi, Yihong, Jarmuszewski, Perry, Certain, Michael
• Granted Patent: US 7,489,905 B2
• Time in Patent Office: Days
• US Class Current: 455/226.200
• CPC Class Codes: H04B 17/20 of receivers
• CPC Class Codes: H04B 17/29 Performance testing

Abstract

A test method is for determining RF path loss between an RF source and an RF receiver. The RF source may transmit RF power values at a relatively fine granularity, and the RF receiver may generate RSSI values at a relatively coarse granularity and have an unknown hysteresis about each transition between adjacent RSSI values. Hysteresis edges may be determined about a given RSSI value transition at the RF receiver by sweeping RF power values transmitted from the RF source in increasing and decreasing directions. A relationship between the relatively fine granularity RF power values and the relative coarse granularity RSSI values may be determined using the hysteresis transition edges. The RF path loss for a given channel may be determined based upon a given RSSI at a given RF power value and the relationship between the relatively fine granularity RF power values and the relative coarse granularity RSSI values.

Claims

1. A test method for determining radio frequency (RF) path loss between an RF source and an RF receiver for a given RF channel in a given RF frequency band, the RF source transmitting RF power values at a relatively fine granularity, the RF receiver generating received signal strength indicator (RSSI) values at a relatively coarse granularity and having an unknown hysteresis about each transition between adjacent RSSI values, the test method comprising:

determining a pair of hysteresis edges about a given RSSI value transition at the RF receiver by sweeping RF power values transmitted from the RF source in increasing and decreasing directions;

determining a relationship between the relatively fine granularity RF power values and the relative coarse granularity RSSI values using the hysteresis transition edges; and

determining the RF path loss for the given channel based upon a given RSSI at a given RF power value and the relationship between the relatively fine granularity RF power values and the relative coarse granularity RSSI values.

2. The test method of claim 1 further comprising:

transmitting from the RF source at an initial RF power level and measuring a corresponding initial RSSI value of the RF receiver; and

setting an initial internal amplification of the RF source based upon a difference between the initial RF power level and the corresponding initial RSSI value.

3. The test method of claim 1 wherein determining the pair of hysteresis edges comprises sweeping in progressively decreasing intervals of RF power values.

4. The test method of claim 1 further comprising:

repeating the three determining steps for at least one other given RF channel in the given RF frequency band to determine a plurality of RF path losses;

determining an RF path loss function based upon the plurality of RF path losses; and

determining an RF path loss for at least one other channel within the given RF frequency band based upon the RF path loss function.

5. The test method of claim 4 wherein determining the RF path loss function comprises determining the RF path loss function based upon a least squares algorithm.

6. The test method of claim 4 wherein determining the RF path loss function comprises determining the RF path loss function using a plurality of splines.

7. The test method of claim 1 wherein the RF receiver comprises a Global System for Mobile Communications (GSM) receiver.

8. The test method of claim 1 wherein the RF receiver comprises a General Packet Radio Service (GPRS) receiver.

9. The test method of claim 1 wherein the RF receiver comprises an Enhanced Data Rates for Global System for Mobile Communications (GSM) Evolution (EDGE) receiver.

10. The test method of claim 1 wherein the RF source comprises a base station emulator.

11. A test method for determining radio frequency (RF) path loss between an RF source and an RF receiver for a given RF channel in a given RF frequency band, the RF source transmitting RF power values at a relatively fine granularity, the RF receiver generating received signal strength indicator (RSSI) values at a relatively coarse granularity and having an unknown hysteresis about each transition between adjacent RSSI values, the test method comprising:

transmitting from the RF source at an initial RF power level and measuring a corresponding initial RSSI value of the RF receiver and

setting an initial internal amplification of the RF source based upon a difference between the initial RF power level and the corresponding initial RSSI value.

determining a pair of hysteresis edges about a given RSSI value transition at the RF receiver by sweeping RF power values transmitted from the RF source in increasing and decreasing directions, and in progressively decreasing intervals of RF power values;

determining a relationship between the relatively fine granularity RF power values and the relative coarse granularity RSSI values using the hysteresis transition edges; and

determining the RF path loss for the given channel based upon a given RSSI at a given RF power value and the relationship between the relatively fine granularity RF power values and the relative coarse granularity RSSI values.

12. The test method of claim 11 further comprising:

repeating the three determining steps for at least one other given RF channel in the given RF frequency band to determine a plurality of RF path losses;

determining an RF path loss function based upon the plurality of RF path losses; and

determining an RF path loss for at least one other channel within the given RF frequency band based upon the RF path loss function.

13. The test method of claim 12 wherein determining the RF path loss function comprises determining the RF path loss function based upon a least squares algorithm.

14. The test method of claim 12 wherein determining the RF path loss function comprises determining the RF path loss function using a plurality of splines.

15. A test system for determining radio frequency (RF) path loss comprising:

an RF source transmitting RF power values at a relatively fine granularity for a given RF channel in a given RF frequency band;

an RF receiver generating received signal strength indicator (RSSI) values at a relatively coarse granularity and having an unknown hysteresis about each transition between adjacent RSSI values; and

a test controller coupled to said RF receiver and said RF source for

determining a pair of hysteresis edges about a given RSSI value transition of said RF receiver based upon sweeping RF power values transmitted from the RF source in increasing and decreasing directions,

determining a relationship between the relatively fine granularity RF power values and the relative coarse granularity RSSI values using the hysteresis transition edges, and

determining the RF path loss for the given channel based upon a given RSSI at a given RF power value and the relationship between the relatively fine granularity RF power values and the relative coarse granularity RSSI values.

16. The test system of claim 15 wherein said test controller measures a corresponding initial RSSI value of said RF receiver based upon an initial RF power level transmitted from said RF source, and sets an initial internal amplification of said RF source based upon a difference between the initial RF power level and the corresponding initial RSSI value.

17. The test system of claim 15 wherein said test controller determines the pair of hysteresis edges based upon sweeping in progressively decreasing intervals of RF power values.

18. The test system of claim 15 wherein said test controller further repeats the three determining steps for at least one other given RF channel in the given RF frequency band to determine a plurality of RF path losses, determines an RF path loss function based upon the plurality of RF path losses, and determines an RF path loss for at least one other channel within the given RF frequency band based upon the RF path loss function.

19. The test system of claim 18 wherein said test controller determines the RF path loss function by determining the RF path loss function based upon a least squares algorithm.

20. The test system of claim 18 wherein said test controller determines the RF path loss function by determining the RF path loss function using a plurality of splines.

21. The test system of claim 15 wherein said RF receiver comprises a Global System for Mobile Communications (GSM) receiver.

22. The test system of claim 15 wherein said RF receiver comprises a General Packet Radio Service (GPRS) receiver.

23. The test system of claim 15 wherein said RF receiver comprises an Enhanced Data Rates for Global System for Mobile Communications (GSM) Evolution (EDGE) receiver.

24. The test system of claim 15 wherein said RF source comprises a base station emulator.