Radiated Antenna Power and Sensitivity (TRP/TIS)
For Radio Compliance, IoT products that feature antennas are measured in terms of their Total Radiated Power (TRP) that must not exceed +23dBm, which is the limit imposed by ETSI EN 301 908-1 as well as FCC part 15 CFR 47. Additionally, Total Isotropic Sensitivity (TIS) should be measured too, which is effectively the Signal to Interference to Noise Ratio (SINR) as seen by the antenna inside the product. While there's no legal compliance requirement for TIS, the majority of Network Operators will require cellular devices to meet their criteria for TIS as well as the minimum acceptable TRP.
Yes, typically TRP is sandwiched between the legal 'ceiling' limit and the minimum acceptable level imposed by the Network Operator / PTCRB.
All of the above makes the process of measuring TIS/TRP very delicate and tricky as it can only be done in a sphere for compliance demonstration. However, in this video I will show how to estimate TIS/TRP by taking a limited number of measurements in 30 degrees steps. I was able to do that with a wireless callbox R&S CMW500 in the local RF anechoic chamber and an ordinary 2GHz horn antenna at the University of Surrey.
R&S CMW500 Radio Communication Tester:
https://www.rohde-schwarz.com/uk/prod...
The 4G/LTE modem I used:
https://www.telit.com/devices/le910cx...
TIMELINE:
00:00 - Start
00:40 - TRP/TIS Definition
04:55 - Measurement Setup
06:22 - Antenna Placement
09:55 - TRP/TIS Measurement
14:12 - TRP Calculation
17:52 - Summary