coexistence testing

Coexistence testing, similar to compatibility testing, is a method of measuring the ability of multiple devices to interact in a single environment with limited bandwidth. As the number of interconnected devices over radio frequency (RF) increases, coexistence refers to ensuring one user's wireless device will not impact another wireless device. Impacts can range from loss of function to corrupted data to interrupted signal.

The first step of coexistence testing is to define the intended environment that the device is most likely to operate under, such as a professional, healthcare or home setting. Next, the primary functions, associated wireless protocols and necessary radio frequency (RF) bands need to be determined. Testing begins by modeling the intended environment and introducing interferences to see how the device and signals react using a spectrum analyzer. Types of setup for coexistence testing include mimicking a realistic wireless open environment or conducting radio frequency over direct coaxial cable connection.

During coexistence testing, devices are categorized based on four risk-based tiers:

1. Major risks associated with the failure of coexistence.
2. Moderate risks, such as delayed or disrupted service, associated with device coexistence.
3. Minor risk, such as inconvenience, associated with device coexistence.
4. Negligible risk where no further testing is needed.

Depending on the device and the returned risk tier, product redesign may need to take place prior to release. Risk management standards require wireless technology to be assessed in relationship to external, potentially hazardous factors. Coexistence of devices can be improved through multiple techniques, such as physical separation, frequency allocation, improved security mechanisms and transmission variation.

The most extreme reason to perform coexistence testing comes from the medical field. As more medical devices are integrating smart technology and being used outside of clinical environments, it is important that their critical functionality is not interrupted. There have been recorded instances of cell phones causing infusion pumps to stop or pacemakers being controlled by unauthorized sources. Manufacturers must test that devices can perform when introduced to external devices or interferences to address concerns of safety, reliability and mortality.

Uses

Coexistence testing can be applied to a wide range of use cases, all varying in severity.

• Ensuring that medical devices peacefully interact with other medical devices in a clinical or commercial environment.
• Testing website functionality across a range of browsers and devices.
• Running applications on a range of operating systems (OS) and versions.
• Analyzing compatibility or integration of various software.
• Examining that IoT devices or smart home configurations perform independently over one network.