Medical Grade WiFi

Below are some good reasons why a medical device manufacturer should carefully choose their preferred embedded wireless technology provider. If you want to know more about Silex Technology expertise and how we can help you to find the right product for your needs, contact your Silex sales representative today.

 
Medical device connectivity has many unique requirements beyond what is demanded by the typical wireless customer. The Wi-Fi silicon suppliers typically focus their attention and energy on the requirements of high-volume consumer applications. As a medical device manufacturer, how can you implement a Wi-Fi solution that addresses your specific needs?

Silex Technology has provided wireless connectivity solutions for medical device manufacturers for more than 10 years. Over this time, our product offerings have evolved to specifically address this vertical market application.

Dual Band Support

Dual-band support (2.4 GHz/5 GHz) is an important feature for new Wi-Fi implementations.
The 5 GHz band support was first introduced in IEEE 802.11a-1999 as an amendment to the IEEE 802.11 specification. It has seen widespread, worldwide implementation, particularly within the corporate workspace. Like 802.11a, 802.11n radios support either single-band (2.4 GHz) or dual-band (2.4 GHz/5 GHz) implementation.
Using the 5 GHz band provides a significant advantage, as the 2.4 GHz band is heavily used, to the point of being crowded. Degradation caused by such conflicts can cause frequent dropped connections and degradation of service. However, the high carrier frequency also has a slight disadvantage: The effective overall range of 5 GHz is slightly less than that of 2.4 GHz because 5 GHz signals are absorbed more readily by walls and other solid objects in their path.
The increased number of usable channels (four to eight times as many in FCC countries) and the near absence of other interfering systems (e.g., microwave ovens, cordless phones, and baby monitors) give dual-band implementations significant aggregate bandwidth and reliability advantages.

Roaming capabilities

Medical devices often transmit critical data such as ECG waveforms while the patient is in transit (e.g., on a gurney). The medical device manufacturer needs a solution that handles access point roaming seamlessly without data loss caused by wireless connectivity problems.

Providing “true” mobile connectivity requires a sophisticated management scheme including these enhancements:

- User configurable handoff threshold
- User configurable multiple SSID list
- Tracking of five or more access points

Silex Technology solutions based on the Qualcomm Atheros AR6003 chipset (with the enhanced Silex Technology driver/supplicant) are validated to roam, on average, in 100 ms or less in an open system environment.

Be sure to understand the roaming performance of the Wi-Fi solution you are considering, along with the underlying algorithms used to make “roaming” decisions.

Long Product Life Cycle

Radio chipsets are designed for high-volume consumer applications, which often have a product life cycle of only a few years to take advantage of the newest technology. “Moore’s law,” which states that computing power doubles every two years, is the driving force for rapid product obsolescence.
On the other hand, medical device manufacturers have long design cycles because patient safety is at stake. As a result, the typical medical device manufacturer prefers to source technology that can be available from five to 10 years.
What can the medical device manufacturer do to solve this problem?
- Radio chipset introduction date. Radio chipsets are generally discontinued based on lack of demand; you can assume that a newer chipset will be around longer than one introduced several years earlier.
- Radio chipset technology. As this is related to the chipset introduction date, you may want to consider whether the chipset you are considering is based on “current” technology. Two main features to consider are the processor interface and wireless standard support. For example, a Cardbus 802.11b solution is likely to have a limited product life, whereas an SDIO 802.11n solution should be around for some time.
- Supply chain management. In most cases, your supplier will not have control over the chipset availability. But that doesn’t mean it cannot offer programs to extend the availability of the product. Find out what your supplier has done in the past and will do for you in the future.
- Flexible design for obsolescence. Depending on the importance of product life cycle for your organization, you may want to consider an implementation that allows for easier transition to new technology. For example, while a system-in-package (SiP) or surface mount module (SMM) implemented on the device PCBA may be most cost effective, any obsolescence will result in a PCBA redesign. Alternatively, an option card solution (i.e., SDIO card form factor) or intelligent module allows you to move to a next-generation wireless solution without impacting your device PCBA.