Much has been written about cell phone usage interfering with medical equipment, (see the attached detailed article from Stephen K. Olsen and I.) Generally, is is my opinion that the effect from cell phone usage is often-mis-understood. Cell phones can trasnmit at relatively high power levels for (perhaps 1 W), for short periods of time; such as during the ring cycle. However if the cellular device is in a resonably good coverage location, the power control algorithms within the phone and the cellular network will call the cell phone to transmit at much lower levels (potentially under 5mW), which is really not a problem. The rationale for a DAS inclusive to the enterprise is to provide a consistent and pervasive signal level of -85dBm (-70dBm for data in some cases). Without this consistency of the optimal signal strength, the uplink that is driving the higher power from the client device can actually decrease the battery life. Witness when you have two bars on the phone in the macro environment, the life of the battery on a charge descreases in an exponential fashion. WLAN client adapters in medical devices (patient monitors, infusion pumps, and patient worn telemetry), are somewhat power hungry, and yet these mobile devices need to operate in such a way to maximize battery longevitiy. Ideal on patient telemety at least two days. In perhaps a discrete WIFI architecture, whereby this is some contention on roaming and signal strength client to AP .configuration 1:1, this in theory could be somewhat a more of a current drain, however this needs to be evaluted on each enterprise model.
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