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Secure Telephony Enters Handheld Cellular Realm

June 2000
By Robert K. Ackerman
E-mail About the Author

Sophisticated telecommunications cryptography once limited to desktop telephones now available in portable, lightweight units.

The communications sanctity inherent in secure telephone units is migrating into the cellular arena with a new generation of handheld devices no larger than conventional commercial mobile telephones. These telephones are designed to provide high-level government and military secure cellular communications while also being able to serve the commercial arena.

A single telephone can be equipped with embedded security algorithms to meet either graduated commercial requirements or stringent government needs. It provides all the common features of a cellular telephone without resorting to a physical security token. As new security standards and capabilities are developed, their algorithms can be downloaded into the cellular unit through a designated terminal.

The encryption capability can be invoked in the middle of a telephone call. A user conversing with an individual possessing a secure telephone, either cellular or landline, merely has to hold down the handheld unit’s send button for a few seconds. This initiates the two-way security function through which each conversant has encryption and decryption performed at each end.

The dual-use encrypted unit requires no appliqués or additional modules. All capabilities are embedded in application-specific integrated circuits, or ASICs, and software. This brings the handheld unit’s size and weight to slightly more than that of the most compact cellular telephones on the market today but still similar to the average commercial unit.

Known as the QSec-800, the telephone is built by QUALCOMM Incorporated, San Diego, California. Developed around commercial handset components, it offers both conventional cellular connectivity and end-to-end encrypted communications. Its technology is based on the company’s code division multiple access (CDMA) protocol, but it can handle both analog and digital connections. Future hardware advances may allow the secure device to tie into global satellite networks.

Describing it as “breakthrough technology,” Vance Tester, director, product management and sales, government systems, at QUALCOMM, explains that the secure telephone is the product of about two years of research. He expects limited commercial deployment by the end of the year, with large commercial applications beginning early in 2001. Government engineers are currently evaluating it for secure use, and the company expects to begin marketing the telephone to potential military customers this year.

While the QSec-800 serves the role of a secure telephone unit (STU)-III for cellular users, it is more than just a STU-III migrated to the cellular world, Tester emphasizes. Unlike the desktop unit, the handheld device does not require a token or key for operation. Individual security is achieved with personal identification numbers (PINs) that users input to gain access to the security function. The unit can provide links at two security levels up through type I.

Secure calls can be placed between two mobile telephones possessing this capability as well as from the QSec-800 to secure terminal equipment via a secure telephone exchange. This would be enabled through the existing infrastructure by work underway on the future narrowband digital terminal (FNBDT) signaling standard.

The telephone works in both digital and analog modes when using the commercial wireless infrastructure. In the digital mode, it operates at 800 megahertz. Secure connections will not work in analog and require access to a digital wireless network.

The telephone can be equipped with two different types of lithium ion batteries. The standard battery can provide 2.7 hours of call time in a conventional CDMA cellular mode but only 2 hours in the secure mode. The slightly larger and heavier extended battery can provide 5.3 hours of conventional talk time and 4 hours of secure links. Standby times are up to 77 hours for the standard battery and up to 154 hours for the extended one. The complete telephone unit weighs 5.9 ounces with the standard battery and 6.8 ounces with the extended battery.

When a user holds down the send key to shift to an encrypted mode, the handheld unit uses the commercial cellular network’s data application to transmit another signal to the receiving telephone. The two units then perform an electronic handshake and establish the secure link.

At the heart of the handheld unit are two ASICs that provide additional processing capability and additional vocoders for the different applications. These two off-the-shelf QUALCOMM chips, the MSM 3000 and the MSM 3100, allow all of the telephone’s functions to be laid out on two component boards, Tester relates. The device’s “additional overhead” with its encryption function required more processing power, he explains. Gil Balaoing, QUALCOMM senior product manager, shares that the company built the software architecture around the processing power expected of these two chips.

Vocoder capability includes regular 13-kilobit clear-channel vocoding in a CDMA call as well as an additional vocoder that is required by new FNBDT security standards.

The unit includes an additional speaker for conference calls and a push-to-talk button for network broadcasting. The network broadcast capability, known as group services technology, will be supported in a QSec-800 once it is made available on a CDMA commercial network. Another feature is a vibrating silent call alert capability. The handset also includes a threaded headset jack on the top of the telephone for users to employ an off-the-shelf surveillance kit. This universal jack permits an operator to attach an earpiece, a microphone and a push-to-talk button through one connection. Other accessories include a car cigarette lighter adapter, a hands-free car kit and data cables for transmitting encrypted data from a PC over the secure cellular links.

The cellular unit offers a key advantage for the secure telephone user, Tester states. Where the sound quality of some secure STU-III conversations allows speech comprehension but not always good voice identification, preliminary QSec-800 user comments describe the QUALCOMM telephone, operating in a secure mode, as providing improved voice recognition.

Several commercial developments contributed to the engineering of this telephone, he notes. In its digital mode, the unit takes advantage of the commercial infrastructure’s data capabilities. The availability of voice over Internet protocol is another bonus, especially for planned enhancements.

At the core is a method of encrypting the conversation on the originating telephone and sending the signal through the commercial network as if it were a typical wireless call. This does not present any special requirements on the commercial infrastructure, Tester states.

Engineers eschewed adapting a Fortezza card for several reasons, he notes. The Fortezza card is a technology that evolved to different standards, and QUALCOMM is able to incorporate its functionality into the QSec-800’s software. Not having the card also allowed designers to plan for a smaller telephone than would be required to accommodate a card slot. Incorporating a Fortezza card would have led to a design closer in size to a land mobile radio rather than a cellular telephone, Balaoing says. The embedded, tokenless product does not sacrifice any capability or performance, he adds.

The biggest challenge overcome in the development process was to break from the conventional token encryption approach and adopt one based on software, according to Balaoing. One hurdle was the hardware development effort coinciding with the government’s creation of FNBDT signaling standards. This parallel development required company engineers to design the telephone simultaneously with the generation of these standards.

The QSec-800 shares considerable commonality with the average cellular telephone, Balaoing continues. Many of the convenience features of commercial cellular telephony are found on the secure unit. The company built on its own proprietary designs for CDMA cellular telephones and also incorporated many advances that were emerging from its laboratories. The ASIC chipsets on which the new unit was based are installed in many QUALCOMM cellular telephones on the market, he states.

Future iterations and capabilities depend in large part on enhancements in the commercial wireless infrastructure, Tester says. One planned improvement is a network broadcast capability that allows a single user to talk to many recipients. This will require the deployment of packet data with dormancy in the commercial infrastructure. Tester states that his company is working with service providers to bring about this new capability. QUALCOMM developed network broadcast capabilities with the encryption capability in what Tester describes as a dual-path development.

Because the telephone’s functionality is software-based, improvements in telecommunications security can be downloaded into the unit via a simple software upgrade. Government users might upgrade their units at a terminal, for example. The government must establish new policy standards to equip personnel with this type of cellular telephone, Tester adds. The near future may see software upgrades sent over the cellular network, depending on the service provider.

The company also continues to develop new chipsets that add functionality. The system’s design supports the ability to incorporate new radio frequency processors for additional frequency bands, Balaoing notes. On the drawing boards is a trimode telephone that would permit the secure function to work on a 1.9 personal communication systems, or PCS, network in addition to the 800-megahertz CDMA network and allow the telephone to function in conventional analog.

Using the FNBDT standard helps ensure a greater degree of interoperability. Balaoing explains that it occurs at the applications layers, so it has an insulating effect for the transport and physical layers. The company is looking at adapting this encryption capability for time division multiple access (TDMA) and group system mobile (GSM) systems.

Other ongoing research aims to modify the developed encryption capability for broader use. This might involve an appliqué arrangement with other handsets employing different interface technologies.

The future might literally be global. If customer interest arises, the secure cellular telephone could be engineered to tie into satellite telephony. This would establish encrypted commercial telephony anywhere, any time, around the world. If the company decides to pursue this capability, overcoming size and weight challenges while marrying the technologies probably would take about two years from the onset of a full research and development effort.

The satellite arena could prove to be a significant market, according to Craig Mathias of the Farpoint Group. Mathias, who is an analyst on wireless communications, emphasizes the importance of security in mobile telephony, including satellite systems. “If the technology were available, we would encourage everyone to get one,” he declares.

QUALCOMM is developing and manufacturing the QSec-800 telephone in house. While the company recently sold its consumer products handset business, it retained the right to continue developing and manufacturing devices that are “of a unique secure nature” that could be used for commercial or national security, Tester says. The company also continues to manufacture Globalstar telephones.

To market the QSec-800 to both government and commercial customers, the company designed it to handle varying degrees of encryption. This required following several different standards, Tester relates. Commercial versions would not include the high-level government encryption capabilities.

The commercial market could include research and development firms, financial sector corporations involved in mergers and acquisitions, and law firms, Tester offers. Security firms, for example, would not need to turn to private encrypted radios or other proprietary solutions. Police departments could use the secure telephones as an increased capacity device to augment overloaded radio networks.

Virtually any business that desires secure wireless telephony can use these devices without extensive add-ons, he states. When not needed for secure communications, the units also can double as ordinary cellular telephones for everyday business use.

The company is negotiating some contracts with large government users, Tester allows. In addition to the high-level federal government market, he sees state and local governments as potential customers. A government telephone would feature several safeguards that would have to be cleared before the unit could be put into use. These would include passwords or PINs as well as special software loads. The main advantage for these smaller government customers is that they could obtain secure wireless connectivity at less cost than expanding their current radio communications networks, Tester suggests.

The company already has been in contact with several U.S. military organizations ranging from the individual services to special groups. This encompasses both tactical applications and commercial military uses such as on ships docked in ports serviced by CDMA cellular systems. A ruggedized version could be in the cards if demand warrants, Tester says.

QUALCOMM has been working with Verizon, which was formed by the merger of Bell Atlantic Mobile, AirTouch Cellular, PrimeCo Personal Communications and AirTouch Paging, on initial testing and joint product launching. The telecommunications service provider is establishing a nationwide cellular system out of its recent mergers and acquisitions, which soon will include the wireless assets of GTE Corporation. Tester explains that Verizon is supporting QUALCOMM’s efforts to introduce the QSec-800 into the government markets. The service provider’s network is an 800-megahertz CDMA digital system to which the telephone is suited.

The QUALCOMM telephone will be made available to any CDMA service provider interested in incorporating it, Tester emphasizes. He believes that the total commercial niche market for these telephones in the United States will reach between 75,000 and 150,000 units within three years.