What is wireless coexistence?
Today’s technology relies on wireless communication, from consumer devices to medical devices. Wireless coexistence is the ability of a device to function correctly in an electromagnetic environment with other unrelated, noisy signals. It’s important to ensure that your medical device can function properly in today’s noisy wireless environment. Imagine operating your device on a busy NYC intersection, the noise and latency would be problematic for your patients. Same problem can happen in an OR or hospital bed littered with electromechanical devices emitting waves.
How is it tested?
Testing your device for wireless coexistence is part of your overall risk management strategy, and is handled by developing a Wireless Coexistence Evaluation Plan. This document will be informed by the relevant international standards for wireless testing, which include AAMI TIR 69 and ANSI C63.27. The Wireless Coexistence Evaluation Plan describes your system, the testing you plan to perform, and the report containing the test results.
In the ANSI C63.27 standard, devices are tiered into 3 tiers depending on the risk that their wireless functions pose. Tier 1 is most thorough, while tier 3 is the minimum amount of testing, and these tiers are correlated to risk categories of major (tier 1), moderate (tier 2), minor (tier 3), or negligible (no testing required). In order to test your device’s wireless coexistence, there are several steps:
- Describe the wireless technology. Specify the wireless communication technology used (i.e. Bluetooth, 802.11a/b/g/n) - include operating frequencies, channels, transmission/receive power, and any other relevant wireless information. Are other devices able to connect to your device’s network? If so, list all relevant devices (i.e. smartphones with the proprietary application, sensors, etc).
- List all functions of the device that require wireless connectivity for proper functioning (i.e. uploading data to a server, reading data from a sensor, sending data to an actuator)
- Describe the configuration of the device under test, specifying what processes will execute the wireless functions during the test (i.e. the test will be conducted using a temperature sensor containing a BLE transceiver communicating with an Android smartphone).
- Define performance requirements for the wireless functions, including clear pass/fail criteria (i.e. successful data transmission is defined as a minimum throughput of 100 kbps).
Once you have completed those steps, you’re ready to perform wireless coexistence testing. Seems like a lot of work? See how Nemedio can help!
