March 23, 2006



Posted: 03.01.05

Gaining Spectrum

Losing patience with dropped signals, one hospital upped the ante
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By Jay Fisher

As the use of wireless technologies in the workplace increases, so, too, does the difficulty of getting
reception everywhere it’s needed. We all know the frustrating experience of walking to the window or outside, so we can continue a conversation on our mobile phones.

The fact is, signals from cell towers, Wi-Fi access points and other types of radio transmitters do not penetrate the walls of buildings well. This problem will only become worse with third-generation, high-data-rate wireless technologies. According to Jeff Kunst of MobileAccess Networks: “3G networks bring signals into the building that require far more spectrum. Much higher power levels are needed to attain these high data rates.” And that means, where signals are weak, transmission and retransmission of data packets will fail.

The solution is simple enough: amplify and rebroadcast wireless signals within buildings and, at least for some applications, increase the number of Wi-Fi access points. But this can mean pulling great lengths of cable through buildings, at significant cost, in order to set up antennas, amplifiers and access points throughout a facility. Even worse, every time a new service comes along, or every time a business wants to change, say, cellular providers, it has to wire yet another network of antennas and amplifiers.

Rice Memorial Hospital, in Willmar, Minn., faced this set of problems. With many thick concrete and fire-proofed walls, parts of the facility below grade, a sprawling campus and construction underway on an entirely new 100,000 square foot facility, cellular coverage was not good. At the same time, says Jon Barber, Rice’s telecommunications coordinator, “It was becoming apparent to us that there were going to be other wireless devices in use that were going to require IP: a wireless LAN or mobile computers, PDAs, things of that nature.”

The need for these technologies in such a setting makes sense, of course; a hospital is an inherently mobile facility. Hospitals are populated with doctors, nurses, patients and visitors, who continually move amongst a series of offices, surgical units, patient rooms, labs and nursing stations, and they all need to communicate with each other.

Traditionally this is done through overhead paging, but that can be disruptive and inefficient, so Rice Memorial has been moving to eliminate this sort of paging altogether. “Just to create a better-feeling environment,” Barber explains, “to cut down on the noise, to cut down on the patient disruption.”

But how to combine all the voice and data services, which allow for the elimination of this sort of paging system, without creating a mess of criss-crossing networks? Rice Memorial turned to MobileAccess Networks and its MA-2000 multi-service remote unit, which can distribute, amplify and rebroadcast everything from two-way radios to cellular and Wi-Fi over the same broadband antenna system. According to Barber, one network that distributes and transmits everything, “was the prime driver for the MobileAccess system. We have these dissimilar technologies, but we want one system to run them on.”

MobileAccess accomplished this by transporting signals throughout a facility over fiber optics and then rebroadcasting the signals over passive broadband coaxial cables and antennas. Operators bring cellular, two-way radio or high-data-rate services into a central telecom room.
These services are all radio frequency (RF) based technologies (e.g., 800 MHz for cellular, 400 MHz for two-way radio). The RF is converted into fiber optics at the base unit and sent out in this form to telecom closets throughout the facility. At the telecom closets, the fiber optic information is converted back into the original RF signals and then sent out over coaxial cables to broadband antennas, designed to cover a particular area. “It’s really a point to multi-point network,” says MobileAccess’ Kunst.

This system has a number of advantages. Fiber optics allows for a single cable to carry all of the wireless signals over large distances, essentially without any data loss. The broadband coaxial cables and antennas allow the RF signals to be rebroadcast in the facility over the same set of antennas. And in the end, every technology (cell phones, PDAs, laptops) works exactly the way it would in any environment, without modification.

Kunst explains: “That’s really the beauty of the
system. I can plug multiple services in. I can take a single fiber cable and a single coaxial cable out to a single radiating location.” What’s more, the system is modular. Users can add and remove [up to 20 different] services without any rewiring.

Today Rice Memorial propagates a SpectraLink voice and text messaging service, WLAN and 850 MHz CDMA cellular service throughout its facility, broadcast on MobileAccess’s network. Rice is also set up to rebroadcast PCS cellular, though it’s yet to deploy this into its network.

Rice Memorial currently uses SpectraLink voice over IP service for in-hospital mobile voice communications, which also includes text messaging as part of its nurse call system. The WLAN allows for the use of COWs (computers on wheels) to update patient charts in their rooms and allows for laptop-based Web casts in nursing education.

Rice Memorial has also been able to mostly lift the common restrictions on cell phone use in the hospital, which can interfere with medical equipment. “Now with the rebroadcast in here,” Barber points out, “[cell phones] are never far from the tower, so they’re emitting very low signal levels. By putting more signal in the air, we reduce our interference problems.”

Though the bottom line wasn’t an overwhelming consideration for Rice Memorial, according to Barber, they have accomplished their goal of combining wireless services into one expandable antenna system. “Our goal is to provide better patient care delivery and more efficient use of employee time. Our goal is to answer the phone when somebody calls and deliver service when they need it. That really is the bottom line.
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