Localized Mobility

Wireless voice over Internet protocol fills a niche in on-site mobility.

by / March 4, 2005
Though cell phones have become ubiquitous in recent years, some environments have more specialized communications needs. Several schools, hospitals and other government entities have deployed voice over Internet protocol (VoIP) via Wi-Fi networks to accommodate workers who are mobile within local environments.

In New Jersey, New Brunswick Public Schools (NBPS) uses VoIP on the district's existing Wi-Fi networks to keep on-site staff communicating, even in places where cell phones lose signals -- and saved the district in ongoing cell phone costs.

In Sacramento, Calif., UC Davis Medical Center deployed hundreds of badges capable of voice-activated calling so hospital staff can more efficiently reach the personnel necessary for patient care.

Mobilizing Patient Care
Wireless VoIP deployed over a Wi-Fi network is just what the doctor ordered for the UC Davis Medical Center.

Typical cell phones are not safe in hospitals, said Thomas Tinstman, associate director of clinical information systems for UC Davis Medical Center. In very rare instances, cell phones can cause interference with some patient care devices, a problem not found with VoIP on a Wi-Fi network.

More than a year ago, Tinstman said, the hospital began testing wireless VoIP devices in the operating room, where staff traditionally relied on intercoms, pagers, and "look and shout" to get the staff and supplies they needed.

The devices were extremely useful in helping OR staff get the appropriate supplies and staff to the OR when needed, said Tinstman.

As a result of the pilot's success, the hospital began distributing Vocera wireless VoIP badges to all mobile hospital employees involved in patient care. He said the Vocera devices, which are nearly hands-free, fit the many levels of mobility of hospital staff, from nurses -- who care for several patients within a unit and occasionally must leave the unit -- to phlebotomists, physical therapists and others involved with patients across many units.

"The nurse taking care of a patient is attempting to communicate with all of the appropriate people to coordinate the care of their four or five patients, and the typical way of solving that problem has been page and call back," he explained. "But if you page somebody, you've got to stand there and wait until they call back."

Staff needn't remember or look up numbers to contact necessary staff members; they can simply push a button on the device and request the person by name. They can also reach personnel by job title, said Tinstman.

"I can say, 'Give me the nearest respiratory therapist,' and it will ring the device of a respiratory therapist who is at an access point nearest to the one I'm calling from."

Tinstman said this capability is configured into the server. When mobile employees arrive for work, they request to be enrolled in the appropriate work category.

"I would call in and say, 'Enroll me in the respiratory therapy group for floor six,' and then any nurse on floor six says, 'Call respiratory therapist for floor six,' and it gives you that person."

Device users can also verbally request an outside line and make calls by saying the desired phone number.

One concern about using the devices in this environment is privacy because nurses sometimes discuss private patient information, said Tinstman, but the problem is easily remedied by connecting a standard cell phone headset to the device.

"Any of a large number of types work," he said. Because intercom-style in the most convenient way to use the badges, Tinstman said staff often wear the headset without plugging it in. "If they get a call where they don't want it broadcasting, they just plug their headset in."

Maximizing the Network
The network on which UC Davis Medical Center deployed the Wi-Fi-based communication devices was intended for multiple uses. The hospital, which contracted with Sprint to design the wireless network, also uses it to distribute electronic medical records and diagnostic images, such as X-rays, to wireless workstations. The hospital is migrating its wired video conferencing abilities for interpretive services to its wireless network as well.

Tinstman said the hospital hopes to connect patient call buttons to the Vocera badges. And as an additional notification method, the hospital may connect alarms from bedside devices, such as infusion pumps, to nurses' badges as well, though he said that may be more difficult because of FDA regulation.

"We're going to try to make [the badges] the connection to most things a nurse needs to know that are digital," he said.

The hospital will eventually distribute just short of 1,000 badges, and hundreds are already in use. In the future, he said the hospital also hopes to take advantage of new cell phones that switch to Wi-Fi-based VoIP as needed.

Tinstman said the medical center is currently conducting a study of its communications costs, but he expects the badges will pay off.

"Our initial analysis says that if we go to Vocera for people within the hospital and cell phones that operate on 802.11 -- so they're safe -- but then switch to standard cell phone for those people whose responsibility goes outside the hospital, that we will get rid of enough pagers and wired telephones to pay the cost."

Fitting NBPS' Needs
Like the UC Davis Medical Center, New Brunswick Public Schools deployed its wireless VoIP phones on a network intended for many uses. In summer 2002, the NBPS handed out approximately 200 wireless VoIP phones to custodians, security guards, maintenance staff and administrators to use while moving about the district's schools.

The NBPS had already created a districtwide VoIP system. Brian Auker, the district's technology director, said the wireless network was implemented for several reasons: to provide Internet access while avoiding costs of wiring individual classrooms in schools where future construction was planned or in schools soon to be torn down; to allow staff to wheel out laptop carts so students and faculty can connect to the Internet anywhere in the school; and to allow for Wi-Fi compatible phones.

Many VoIP over Wi-Fi deployments occur in localized environments where enterprises can take advantage of the cost-savings, said Steve Childs, product manager for Cisco.

"We're seeing most of the deployments in hospital or warehouse environments, where you've got people that require mobility and connectivity," Childs said. "This allows them to use their existing wireless infrastructure to reduce costs."

With the network already in place, the district only paid the cost of the phones -- approximately $500 per phone -- Auker said, and though $500 per phone may sound steep, the phones are worth it.

"Once the infrastructure's in place, there are no more recurring costs," he said. "It's much more cost-effective than cell phones, where you've got to keep paying monthly fees, and you have people watching their minutes so they don't go over, and then they get extra charges and things like that."

The district uses Cisco's 7920 wireless IP phones. Though it started out with a different vendor, Auker said the district switched to Cisco's model, which proved more reliable.

Auker said the wireless VoIP phones can provide benefits for security staff that the previous walkie-talkies could not. Prior to using wireless VoIP phones, he said, a security guard on the playground witnessed a passerby on the street in front of the playground who tripped and broke his nose. When the security guard called the school office for help, no one was on the other end.

"One secretary had gone to use the copier outside the office, the other had gone down the hall to find a teacher, and there was nobody there," he said. "So it took a couple of minutes until he was able to get ahold of somebody to then call for help. What if that had been a student, and what if it had been a more serious injury? A walkie-talkie is a pretty limited device if there's nobody on the other end to answer it."

Now security guards, equipped with wireless VoIP phones, can simply dial 911 in an emergency. Auker said the system has been set up so that if a 911 call is made, it is specially routed through the school's phone line so the call will report the proper address for E-911 purposes, rather than sending the call over the districtwide VoIP network, which would report the district's business office address. Non-911 calls are routed across the VoIP network and back to fiber-optic lines at the board office.

Future Plans
Mobile phones for each teacher will be rolled out over the next 10 to 15 years as part of planned construction projects in the district, said Auker. Giving teachers communications devices that allow on-campus mobility is practical, he said, because teachers sometimes must accompany classes to places outside the classroom, such as the library, lunchroom or playground.

Security is another reason teachers will benefit from the ability to move around with their phones.

"If something happened -- there's someone running around the school with a gun or some other problem like that -- it would be better for the teacher to have a wireless phone because they don't want to be standing by the door speaking on a regular wired phone."

The district also plans to expand the Wi-Fi networks to areas around the school, such as parking lots or bus loading areas, Auker said. Currently he said staff must rely on signals that bleed through the wall of the building when they are in outdoor areas, and they sometimes lose connectivity.

"When we first put in the wireless network, we didn't actually take into account how often they would really want those phones to work outside." Auker said the need for outdoor signals will be addressed in future construction projects.

Maintaining Quality
The wireless VoIP phones are comparable to landline phones in terms of quality, Auker noted. "There's really no difference. Because it's digital, it is not picking up the same type of interference and things you get with a cell transmission."

The network must be properly set up to support wireless VoIP phones, however, to produce such quality. "That has to be the No. 1 piece of data that gets routed through your network because there can't be any lags or slowdowns because of a lot of data traffic."

According to vice president and general manager for Cisco's government systems unit, Ed Carney, e-mails, large files, and so on typically are sent over a network in bursts. So a lot of data may be sent across the network at once, he said, and then there could be nothing for a second.

"With voice, you've got different QoS considerations where you're sending a steady stream of data, and you need to be sure it all arrives there around the same amount of time," Carney said.

Quality of service requirements are set up using software that runs on the routers and switches, which Auker compared with traffic cops at busy intersections. "If data comes through and it's labeled as 'voice,' that's like an ambulance coming through the intersection. Everybody else has to stop."

More Mobility
While the network works well for on-site staff such as custodians and security staff, Auker said maintenance staff must supplement the Wi-Fi phones with cell phones because maintenance staff work at the district level and travel from school to school.

"One of the problems with the wireless IP phones is that you actually have to be in the building for them to work. They don't work when you're driving down the street or when you're at the hardware store picking up supplies."

Auker said the district would look into replacing the district's cellular phones with cell phones capable of switching to Wi-Fi-based VoIP when they become available.

Hybrid phones capable of switching from a Wi-Fi network to a cellular environment and vice versa are just hitting the market, and are not yet widely available. Some say acceptance from cellular providers may be slow because providers would have to give up revenue to local VoIP environments.

"It will be tough for service providers to make a business case around this technology, as it would require giving up their revenue to a LAN environment by providing an end point," said Cisco's Childs, "but it will be a model providers will have to address."

Though cellular providers may not warmly receive the technology, hybrid phones may force their way into the market as providers vying for market share struggle to remain competitive. Some cellular providers are already looking into incorporating the technology, according to news reports, and VoIP over Wi-Fi implementations at the local level may give cellular providers reason to support wireless VoIP.

Rio Rancho, N.M., recently worked out an agreement with Azulstar Networks to implement a citywide Wi-Fi network, which will support wireless VoIP. Soon, Azulstar's broadband wireless customers will also be able to opt for wireless VoIP service in Grand Haven, Mich.
Emily Montandon Staff Writer/Copy Editor