Today’s WLAN for healthcare is faced with a variety of data, voice, and also WLAN enabled medical devices. Doing so, the IT administrator especially in light of pending IEC 80001 is often faced with building out this network for high redundancy, fail-over, security, and quality of service. Thus his/her medical grade “wireless network” has to be built in a mission critical way. There has been much talk and discussion over the past several years about why it is felt that WLAN needs to be separate from the DAS. Especially now with 802.11n, it simple does not make financial or technical sense. This is supported by the WiFi Alliance and pending “draft” of IEC 80001. MIMO is a whole separate discussion, but is supporting this, when you peel away the onion and understand this.
However, with 802.11a at 5.0GHz this poses a lot of challenges from a link budget perspective. It (802.11a) also seems to be somewhat the trend that folks are now attempting to use the 5.0GHz spectrum more, and moving out of the crowded 2.4GHz at least in the medical device space.
I have blogged previously about the link budget and what this means. DAS designs are for lower frequencies such as public safety, cellular, PCS, and AWS. Generally this design model is from 700MHz to 1900MHz. To ensure that that a 5.0 GHzsignal is propagated across a coaxial infrastructure like a DAS; the signal has to be amplified. It is not me saying this, it is simply the laws of physics.
This amplification will need to occur both at the actual antenna element (ceiling)and in the wiring closet.
Adding “active” powered elements to a “life critical WLAN” in this design (802.11a over distributed antenna system)…adds two potential critical points of failure.
With all the need for redundancy to support data, voice, and WLAN enabled medical devices, adding active (powered) components into a design that can potentially fail simply does not make sense. Stay with a discrete WLAN model…period. What do you think?
