Measuring absolute total isotropic sensitivity of wireless communication devices in scattered field chambers

• US 7,995,968 B2
• Filed: 02/11/2009
• Issued: 08/09/2011
• Est. Priority Date: 02/11/2009
• Status: Expired due to Fees

• Current Assignee: Sony Ericsson Mobile Communications AB (Sony Group Corp.)
• Original Assignee: Sony Ericsson Mobile Communications AB (Sony Group Corp.)
• Inventors: Sotoudeh, Omid
• Primary Examiner(s): Cordero; Marivelisse Santiago
• Assistant Examiner(s): Choo; Munsoon
• Application Number:
  US12/369,299
• Publication Number:
  US 20100203880A1
• Time in Patent Office: 909 Days
• Field of Search: 455 6711- 6712, 455423-424
• US Class Current: 455/67.12
• CPC Class Codes: H04B 17/0087 using auxiliary channels or channel simulators
• CPC Class Codes: H04B 17/29 Performance testing
• CPC Class Codes: H04B 17/318 Received signal strength
• CPC Class Codes: H04B 17/3911 Fading models or fading generators

Abstract

The absolute total isotropic sensitivity is determined for a communication device receiver circuit that is within a scattered field chamber (SFC) and is receiving communications from a base station simulator. Movement of a mode stirrer device within the SFC is controlled to sequentially move the mode stirrer device to a plurality of different static positions. The different static positions of the mode stirrer device are configured to differently mix polarizations of incident RF fields in the SFC. At each of a plurality of the different static positions of the mode stirrer device, the transmission power level from the base station simulator is varied through a plurality of different transmission power levels. At each of a plurality of the transmission power levels, a bit error rate and a received signal strength at which the communication device receives the communications from the base station simulator are measured. The absolute total isotropic sensitivity of the communication device receiver circuit is determined in response to the measured bit error rate, the measured received signal strength, and the associated transmission power levels.

Claims

1. A method of determining characteristics of a communication device receiver circuit within a scattered field chamber (SFC) that is receiving communications from a base station simulator, the method comprising:

controlling movement of a mode stirrer device within the SFC to sequentially move the mode stirrer device to a plurality of different static positions, wherein the different static positions of the mode stirrer device are configured to differently mix polarizations of incident RF fields in the SFC;

at each of a plurality of the different static positions of the mode stirrer device, varying the transmission power level from the base station simulator through a plurality of different transmission power levels;

at each of a plurality of the transmission power levels, measuring a bit error rate and a received signal strength at which the communication device receives the communications from the base station simulator; and

determining an absolute total isotropic sensitivity of the communication device receiver circuit in response to the measured bit error rate, the measured received signal strength, and the associated transmission power levels.

2. The method of claim 1, wherein measurement of the bit error rate comprises measuring a frame error rate at which the mobile terminal receives the communications from the base station simulator at the associated transmission power level.

3. The method of claim 1, wherein measurement of the bit error rate comprises measuring a block error rate at which the mobile terminal receives the communications from the base station simulator at the associated transmission power level.

4. The method of claim 1, wherein determination of the total isotropic sensitivity comprises:

for each of the plurality of different static positions of the mode stirrer device, determining a combined chamber and antenna loss (CAL) value using the measured received signal strength and the associated transmission power level from the base station simulator;

for each of the plurality of different static positions of the mode stirrer device, determining an average CAL value using the determined CAL values that correspond to non-zero bit error rate measurements; and

determining an isotropic sensitivity of the communication device receiver circuit using the average CAL value determined for each of the plurality of different static positions of the mode stirrer device.

5. The method of claim 4, wherein:

for each of the plurality of different static positions of the mode stirrer device, the CAL value is determined based on a difference between the measured received signal strength and the associated transmission power level from the base station simulator.

6. The method of claim 4, wherein determination of the isotropic sensitivity comprises:

for each of the plurality of different static positions of the mode stirrer device, determining the isotropic sensitivity of the communication device receiver circuit using the measured bit error rate and the average CAL value.

7. The method of claim 6, wherein determination of the isotropic sensitivity further comprises:

for each of the plurality of different static positions of the mode stirrer device, the isotropic sensitivity of the communication device receiver circuit is determined based on a difference between the measured bit error rate and the average CAL value.

8. The method of claim 6, wherein determination of the isotropic sensitivity further comprises:

carrying out a linear curve fit through a plurality of the isotropic sensitivity values determined for the plurality of different static positions of the mode stirrer device.

9. The method of claim 4, further comprising:

determining an active antenna efficiency of the communication device receiver circuit receiving communications from the base station simulator; and

determining the absolute total isotropic sensitivity of the communication device receiver circuit in response to the determined isotropic sensitivity and the determined active antenna efficiency.

10. The method of claim 9, wherein determination of the absolute total isotropic sensitivity of the communication device receiver circuit comprises adding the determined isotropic sensitivity and the determined active antenna efficiency.

11. The method of claim 9, wherein determination of the active antenna efficiency of the communication device receiver circuit comprises:

while maintaining a substantially constant transmission power level from the base station simulator, moving the mode stirrer device to mix polarizations of incident RF fields in the SFC while measuring a received signal strength at which the communication device receives the communications from the base station simulator;

averaging a plurality of the measurements of the received signal strength over time; and

determining the active antenna efficiency based on the averaged received signal strength.

12. The method of claim 11, further comprising:

determining a transfer function of the SFC, and wherein the active antenna efficiency is determined based on a difference between the transmission power level from the base station simulator and a sum of the transfer function of the SFC and the averaged received signal strength.

13. A system comprising:

a base station simulator that is configured to communicate to a communication device receiver circuit in a scattered field chamber (SFC);

a TIS (Total Isotropic Sensitivity) measurement computer that is configured as follows;

to control movement of a mode stirrer device within the SFC to sequentially move the mode stirrer device to a plurality of different static positions, wherein the different static positions of the mode stirrer device are configured to differently mix polarizations of incident RF fields in the SFC;

at each of a plurality of the different static positions of the mode stirrer device, to vary the transmission power level from the base station simulator through a plurality of different transmission power levels;

at each of a plurality of the transmission power levels, to measure a bit error rate and a received signal strength at which the communication device receives the communications from the base station simulator;

to determine an absolute total isotropic sensitivity of the communication device receiver circuit in response to the measured bit error rate, the measured received signal strength, and the associated transmission power levels.

14. The system of claim 13, wherein the TIS measurement computer is further configured as follows:

for each of the plurality of different static positions of the mode stirrer device, to determine a combined chamber and antenna loss (CAL) value based on a difference between the measured received signal strength and the associated transmission power level from the base station simulator;

for each of the plurality of different static positions of the mode stirrer device, to determine an average CAL value using the determined CAL values that correspond to non-zero bit error rate measurements; and

to determine an isotropic sensitivity of the communication device receiver circuit using the average CAL value determined for each of the plurality of different static positions of the mode stirrer device.

15. The system of claim 14, wherein the TIS measurement computer is further configured as follows:

for each of the plurality of different static positions of the mode stirrer device, to determine the isotropic sensitivity of the communication device receiver circuit based on a difference between the measured bit error rate and the average CAL value.

16. The system of claim 14, wherein the TIS measurement computer is further configured to determine an active antenna efficiency of the communication device receiver circuit receiving communications from the base station simulator, and to determine the absolute total isotropic sensitivity of the communication device receiver circuit in response to the determined isotropic sensitivity and the determined active antenna efficiency.

17. The system of claim 16, wherein the TIS measurement computer is further configured to determine the absolute total isotropic sensitivity of the communication device receiver circuit based on adding the determined isotropic sensitivity and the determined active antenna efficiency.

18. The system of claim 16, wherein the TIS measurement computer is further configured as follows:

while a substantially constant transmission power level from the base station simulator is maintained, to move the mode stirrer device to mix polarizations of incident RF fields in the SFC while measuring a received signal strength at which the communication device receives the communications from the base station simulator;

to average a plurality of the measurements of the received signal strength over time; and

to determine the active antenna efficiency based on the averaged received signal strength.

19. The system of claim 18, wherein the TIS measurement computer is further configured to determine a transfer function of the SFC, and to determine the active antenna efficiency based on a difference between the transmission power level from the base station simulator and a sum of the transfer function of the SFC and the averaged received signal strength.

20. A non-transitory computer readable medium having computer-readable program code embodied in said medium for determining characteristics of a communication device receiver circuit within a scattered field chamber (SFC) that is receiving communications from a base station simulator,

said computer-readable program code comprising:

computer readable program code configured to control movement of a mode stirrer device within the SFC to sequentially move the mode stirrer device to a plurality of different static positions, wherein the different static positions of the mode stirrer device are configured to differently mix polarizations of incident RF fields in the SFC;

computer-readable program code configured to, at each of a plurality of the different static positions of the mode stirrer device, vary the transmission power level from the base station simulator through a plurality of different transmission power levels;

computer readable program code configured to, at each of a plurality of the transmission power levels, measure a bit error rate and a received signal strength at which the communication device receives the communications from the base station simulator; and

computer readable program code configured to determine an absolute total isotropic sensitivity of the communication device receiver circuit in response to the measured bit error rate, the measured received signal strength, and the associated transmission power levels.