June 1, 2021
Elite’s Over-the-Air (OTA) measurements of TRP and TIS can improve and optimize an IoT device for range, reliability, and battery life. Here’s a brief background on how these measurements can help Make a Better IoT Device.
In many cases, engineers design their IoT radio-enabled devices relying on radio OEM data such as conducted RF power and separate data for the antenna such as passive measurements of gain, efficiency, or directivity. While this approach is the basic and necessary initial step, the downside is that using individual component data does not account for all the integration nuances and coupling interactions when the antenna is configured to the radio.
Imprecise impedance matching between the radio and the antenna or design modeling tolerances can lead to higher VSWR than expected and sap the transmitter range and the device’s battery life. There may also be coupling losses resulting from antenna placement near metal elements. In addition, close proximity of antennas near digital noise sources can degrade receiver sensitivity resulting in a penalty to the RF link budget.
A better approach for RF designers is using TRP (Total Radiated Power) and TIS (Total Isotropic Sensitivity) measurements to optimize designs.
What is TRP (Total Radiated Power)?
TRP is the transmitter metric that evaluates the radiated performance of the radio and its antennas as a combined system. The result is based on the measurement of effective Isotropic Radiated Power (EIRP) at a specified distance and from multiple discrete points around the radio/antenna, and then integrating the individual measurements to arrive at a single performance metric. TRP data provides true measured performance with all system integration influences incorporated in the final result.
In addition to transmit aspect of the radio, receiver sensitivity can also greatly affect a successful radio IoT application. Sensitivity is the minimum threshold of RF energy the receiver can detect and still successfully demodulate the transmitted information. Sensitivity values are published by the radio module OEM but they have conducted measurements at the radio port and don’t tell the whole story. The receiver sensitivity and overall performance may be further degraded by an inefficient antenna, or one placed at a sub-optimal location nearby metallic structures, or close to radio host electronics.
What is TIS (Total Isotropic Sensitivity)?
To better gage the receiver performance radiated TIS is used to evaluate the design of the radio receiver and antenna as a system. TIS is a metric that is calculated as the integral of individual receiver sensitivity measurements taken from multiple discrete points around the radio antenna system. TIS takes into account the antenna design and placement as well as the unwanted interference from transmitter and digital host spurious noise. These unwanted interference sources coupled by the antenna into the front end of the radio receiver can greatly reduce the receiver performance. TIS testing is critical to evaluate and reduce the impact of receiver desensitization.
TRP and TIS requirements are often more challenging to meet than the regulatory spurious emissions compliance limits. They are such important metrics that nearly all cellular network operators require TIS and TRP measurements as part of the operator certification process.
As a CTIA Authorized Test Lab, Elite is capable of performing carrier TRP and TIS measurements. We work with our PTCRB partners to help clients achieve the range of compliance from regulatory to carrier certifications.
Regardless if the radio applications are for cellular, Bluetooth, WiFi, or others, TRP and TIS measurements can help improve radio performance for IoT devices and help ensure a more successful application.
For more information on how Elite’s TRP and TIS testing can help your next IoT application, or to help with your carrier certification, contact our OTA specialists today to discuss how we can help.