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Wireless lets you travel, but not far or fast by George Spain IS Technical Publisher We've come to expect a lot from computers. Beautiful graphics, great sound, answers to our questions at our fingertips. They're take-anywhere, do-anything genies with lightning response times. There are times, however, when the performance can't keep up with the promise—wireless computing.   Freed from cords, wires, and phone lines, computers are becoming more convenient, but there's a tradeoff—speed.   Desktop boxes, those encumbered with plugs and wires are getting faster even as they get smaller. Most desktops at MUSC are plugged into 100 megabytes per second (mbs) connections. Wireless computers, such as those that can be found on hospital floors (commonly called Computers On Wheels or COWS) however, are restricted by current technology to about 54 mbs.   That's half as fast—at best. But it gets worse. The real goblin is bandwidth, the amount of transmission space available on the radio waves that carry the wireless signals. These are the antennas you see affixed to hospital ceilings. Both distance and number of users limit bandwidth. In other words, the farther the device is from the antenna and the more people using the same connection, the slower the response.   The good news is, it's gotten better. Original wireless signals were limited to 11mbs, far slower than the 54 allowed today. The bad news, it's getting crowded. More and more wireless devices are finding their way into hospital floors. COWS are just one example. In the next few years, more and more data will be pushed through the wireless domain. McKesson applications, a crucial part of the Advanced Point of Care (APOC) clinical information system now being implemented at MUSC, will require that even more data be moved over wireless networks.   “You have to understand that wireless for clinical applications is just beginning to be heavily utilized. Prior to last year the only thing they used OACIS for was review of information and they did not use wireless COWS or tablets. Now they use it for data entry. We are rolling out McKesson applications that will use it [wireless] for much more data entry including orders and interdisciplinary documentation,” said Jacque Dunning, a clinical analyst with the office of the CIO's Information Services (IS).   Michael Haschker, network systems manager for IS, puts it this way, “wireless is a shared medium… at best you get 54 mbs divided by the number of clients multiplied by their average bandwidth. This means you can have eight people using 5.5 mbs, 16 people using three mbs each, or two people at 27 mbs at any one time.”   Haschker calls file sharing and database applications the real wireless hogs. By comparison, web-based applications use little bandwidth.   While the migration to wireless was inevitable and it has been a success, it's impact on workflow is still being discovered.    “When the wireless devices were put on the units I am not sure that all users, let alone all IT staff, understood what amount of data transfer is maximal nor how that changes with use of the IP phones,” said Dunning.   Is the answer to add more access points?   “No,” said Haschker. “We cannot add more access points. We are limited to three in a coverage area because there are only three non-overlapping channels for use in 802.11b/g (the current prime wireless protocol). Faster wireless protocols have been specified, but none are yet available on a production basis.”     Friday, Oct. 27, 2006 Catalyst Online is published weekly, updated as needed and improved from time to time by the MUSC Office of Public Relations for the faculty, employees and students of the Medical University of South Carolina. Catalyst Online editor, Kim Draughn, can be reached at 792-4107 or by email, catalyst@musc.edu. Editorial copy can be submitted to Catalyst Online and to The Catalyst in print by fax, 792-6723, or by email to catalyst@musc.edu. To place an ad in The Catalyst hardcopy, call Island Publications at 849-1778, ext. 201.