Four Steps to Prepare for Wireless Coexistence

Technology trends continue to drive the rapid growth of wireless devices, particularly in the medical industry. These trends have created new challenges for product developers, especially when it comes to the safe operation of their products in increasingly crowded spaces.

According to guidance published by the FDA, “potential risks that can affect consistent and timely wireless medical device functions include data corruption or loss and interference from simultaneous transmitters in a given location, which can increase latency and transmitted signal error rates.” These risks, identified early by the FDA, must be quantified, mitigated, and managed to stay at or below acceptable levels. One important method for doing so is wireless coexistence testing.

At its inception, wireless coexistence test methods varied greatly, but since then, established processes and standards were developed to provide more reliable test data and results.

Four steps for successful wireless coexistence testing

To ensure your products are prepared for successful wireless coexistence testing, you must define the product’s intended environment and determine the product’s risk level. 

Step 1: Define your product’s intended environment

To define your product’s risk level, you must first define its intended environment. You will need to decide where the product will be used, what other products and devices may be used in that area, how the product will be used, and which RF bands and wireless protocols the device will use.

The ANSI C63.27 standard should be considered if equipment relies on wireless communication. ANSI C63.27 specifies methods for assessing the radio frequency (RF) wireless coexistence of equipment that incorporates RF communications and identifies key performance indicators (KPIs) that can be used to assess the ability of the equipment to coexist with other equipment. Bluetooth, Wi-Fi, LTE, and DECT are the principle technologies and bands that are addressed by the current standard. 

If the medical device is expected to operate in a healthcare environment near RFID readers, then the AIM 7351731 standard should be considered as well. The standard provides test methods and test levels for electromagnetic immunity of (non-implantable) medical electrical equipment and systems. AIM 7351731 is considered to be an immunity standard by the FDA, similar to IEC 60601-1-2 Radiated Immunity, so results should be evaluated against essential performance.

Step 2: Determine your product’s risk level

Products fall under four risk-based tiers per AAMI TIR 69. The tiers listed below help determine what level of testing is necessary to ensure safe operation.

• Tier 1: Major risks, including those that can cause death or serious injury. Requires thorough testing with three competing devices.
• Tier 2: Moderate risks, including delayed or disrupted service. Requires testing with two competing devices.
• Tier 3: Minor risks that do not significantly impact health. Requires minimal testing with a single competing device.
• Tier 4: Negligible risks that provide minor inconvenience or discomfort. No testing required.

ANSI C63.27 Section 5.4 provides details on the test levels required for each tier.

Step 3: Determine performance parameters

Once you have defined the products’ intended environment, you will also need to determine what optimum performance looks like for your device. 

Based on this information, what is acceptable failure? Are there times when some level of failure is acceptable, or does the product need to work perfectly every single use? These considerations help with the creation of your test plan.

Step 4: Bring in the experts

Once you have completed the steps above, it’s time to talk to our wireless coexistence testing experts. Working with our laboratories, you will be able to create a test plan that clearly describes what will be tested and the method of testing that is to be completed. After creating and receiving approval for your test plan, the testing may begin.

Element offers all necessary wireless coexistence testing and provides full documentation of the test methods and results. The documentation provided is to be submitted along with your product’s other credentials to receive product approval.

Questions? 

Contact Element’s experts to learn more about our services and how you can successfully prepare for wireless coexistence testing.