VoIP, Wireless Communications Challenge 911 System

Increasingly, individuals work with cell phones rather than landlines, and businesses and consumers are reducing their telecommunications costs by installing Voice over IP (VoIP) links. The transformation from the Public Switched Telephone Network (PSTN) to next generation (wireless and Internet) services is well underway; however, while the new technologies offer many benefits, they also have one limitation: They may not work with 911 services.

Aware of the problem, users, special interest groups and the government have been pushing equipment vendors and service providers to support a new emergency-calling system, dubbed e911. This service not only works with new technologies, but it also provides additional data to emergency responders, such as specific locations inside large buildings, so they are better able to respond to emergencies.

Bypassing the Barriers

While the new service has potential advantages, its deployment presents significant technical challenges that vendors have only begun to address.

To understand the challenges, one needs to take a close look at how emergency calls are transmitted. They start off in an end user device, which can now be a wireless or wireline phone, a computer or Personal Digital Assistant (PDA). The call is then transmitted to a central call routing system, such as PBX or a voice communications server.

Next, the call is handed to a service provider who then delivers it to one of approximately 6,000 911 emergency call centers located throughout the U.S. — these centers are known as Public Safety Answering Points (PSAPs). Emergency line personnel then work with local responders to provide emergency services.

Fixed No More

The old 911 system worked because the end points were fixed, and the PSTN carried the caller information — basically, caller ID data such as name and address — along with the call throughout the transmission. That is not the case with the new telecommunications systems for a few reasons.

First, users are no longer stationary, so no one can be sure where a call may originate. Also unlike the PSTN, IP networks were not designed to identify callers’ locations, but instead to determine whether or not they were authorized to access the network.

“IP and cellular networks do not provide visibility to the end user; instead they only ‘see’ down to the switch or server controlling the call,” said Matthias Machowinski, Directing Analyst, Enterprise Voice and Data at Infonetics Research.

This creates problems because users now freely travel from one wireless PBX or LAN access point to another. Theoretically, an ambulance might be routed to a company data center while the 911 caller is actually a mile away, in the branch office.

Vendors and the government have been trying to rectify that problem. In 2000, the Federal Communications Commission started focusing on enhancing wireless networks, so they could support e911 services. That was important because U.S. wireless users already place 50 million (approximately 30 percent of the total) 911 calls each year, and that number has been steadily rising.

The FCC embarked on a five year plan that will be completed in December 2005. Once finished, this phased approach should enable emergency personnel to identify wireless network users’ locations within 1,000 feet of where they place their calls.

You Fill in the Blanks

In its wireless and VoIP initiatives, the FCC outlined broad objectives and then left it up to network equipment vendors and service providers to meet them. Vendors and service providers have been moving in a step-by-step fashion to adhere to the objectives.

The cellular industry has been working on different options, and the most popular one aligns cellular and Global Positioning System (GPS) technology. GPS systems transmit information from remote devices to satellites revolving around the earth.

During the past few years, handset vendors have included GPS capabilities in their products and service providers have signed agreements with firms that provide GPS tracking services, like Cell-Loc Location Technologies and SnapTrack. As a result, when a 911 call is made from a cell phone, the caller’s number can be matched to the GPS location key that is sent to the PSAP and provides responders with a geographical reference point for the caller.

While helpful, this is not a foolproof solution. “GPS systems only work within certain ranges,” said Bob Egan, president of consulting firm Mobile Competency. “If a user is inside a building, the system may not be able to see him.”

Another issue is that cellular carriers have missed a few of the FCC deadlines: They were originally supposed to complete the work by the end of 2004, but were granted an extension. “I wouldn’t be surprised if there were more deployment delays at the end of this year,” said Neil Strother, an industry analyst with In-Stat/MDR.

VoIP Voice is Heard

In May 2005, the FCC turned its attention to VoIP networks. In the long term, the federal agency wants VoIP service providers to offer similar services as PSTN service providers, but the agency has not yet outlined its compliance requirements or established a timetable

Already, one issue has arisen: The breadth of the FCC initiatives. They cover telecommunications services, but not wireless enterprise PBXes or VoIP servers that companies operate.

Vendors have enhanced their products to support emergency calls, but many of the improvements have been based on proprietary technology and offer only limited visibility about a caller’s location. In most cases, they offer complete visibility only when an enterprise has one vendor’s network equipment — a possibility but not a probability in most cases. Also, since these approaches are based on proprietary technology, they can be expensive and often can not be easily mixed and matched.

The Telecommunications Industry Association (TIA), an ad hoc standards making consortium, has been trying to make it possible for wireless and VoIP networks to transmit location data in a standard manner. The TIA’s Link Layer Discovery Protocol-Media Endpoint Discovery (LLDP-MED) standard, which is now in draft form, facilitates information sharing between endpoints and network infrastructure devices, such as access points. Support for the standard is expected to be incorporated in various products during the next 12 to 24 months.

A Long Road, a Rosy Future

While a great deal of progress has been made in filling 911 holes, more work needs to be done.

Supporters of e911 think that the work will prove to be worthwhile because the new services can take advantage of new multimedia capabilities. In the future, callers may have the ability to send video from emergency scenes — picture a cameraphone sending pictures of a fire to dispatchers, or responders sending video instruction on CPR basics to callers.

“Once e911 services are available, a better emergency services system will be in place,” Mobile Competency’s Egan told TechNewsWorld. “The question now is: How long will the transition to these new services take?”

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