As a product, cellular voice has been a spectacular exception to the current slow growth rate for most industries. In fact, some experts claim that cellular’s coming of age is unparalleled in consumer electronics.
“I think it’s terribly significant that this industry has gone out and spent $16 billion in private capital to bring wireless communications to 95 percent of the (U.S.) population,” said Thomas E. Wheeler, president of the Cellular Telecommunications Industry Association. “There’s never been a consumer electronics product that has reached 20 million (users) in just 11 years.”
Backing his claims is CTIA’s September 1994 semi-annual survey of cellular industry growth. To date, cellular carriers have activated nearly 20 million phone subscribers, reports the survey. Among other items, the survey points out yet another impressive industry leap-for the 12 months ending June 30, 1994, cellular revenues have increased 48 percent, totaling $12.6 billion.
According to Wheeler, more than 17,000 new cellular customers are added each day, with two out of every three new phone numbers going to wireless customers.
Enter cellular data
Add to this marketer’s dream a new set of data-over-cellular services, and suddenly cellular, as a product, steps into a new era of voice and data capabilities.
With these capabilities, companies can now use voice and data communications to economically re-engineer their sales or field operations, place real-time orders, improve tracking, dispatching and fleet management activities, have machines communicate with other machines or simply enhance the capabilities of their mobile work force.
Take the recent experience of United Parcel Service. With more than 50,000 trucks traveling to all corners of the United States, the company wanted to keep real-time track of every UPS parcel. After researching the possibilities, UPS opted for a custom-designed cellular data solution to meet its needs.
In the end, UPS developed a successful wireless data system that instantly tracks each UPS package, allowing UPS to know its precise location. In addition, customer satisfaction has increased dramatically with the new cellular data system.
But why is it that cellular data has suddenly become a part of the cellular equation? Though it has been technically feasible to use the existing cellular network for voice and data for several years now, until recently the supporting technologies were not in place to make mobile cellular data easy to use.
Necessary was the evolution of powerful laptop and handheld computing devices. Also required were modems designed to solidify the data-over-cellular connection. Today, these computing devices and cellular-enhanced modems are in the mainstream, making it convenient to use cellular for data and voice communications.
So now, you can send electronic mail, faxes or files to colleagues with a cellular phone/modem linked to a laptop, handheld device or a mobile data terminal. You also can tap into proprietary company bulletin boards, public information services or control remote computers, such as an office workstation-all over cellular.
In addition to data, you also can use cellular voice capabilities in your wireless communications.
Cellular data 101
Though wireless data has acquired a number of nicknames in a short time, from “wireless computing” to “mobile computing,” the technologies that bind these euphemisms often are not clearly defined.
To fully understand the new data cellular capabilities, some clarification is in order, including an overview of the kinds of cellular data technologies that are currently available, the strengths each technology has to offer, and a look at the services and equipment that help to enhance mobile productivity.
Currently, two technologies are available for sending data over the cellular network-the existing circuit-switched system, and the new Cellular Digital Packet Data (CDPD) system, which is an overlay to the existing circuit-switched network. These technologies are complementary, each serving a specialized niche to enhance data transmissions over the cellular network.
Some U.S. cellular carriers have adopted both technologies, and are making them available in their markets. A case in point is Walnut Creek, Calif.-based AirTouch Cellular, which currently supports circuit-switched cellular data services, and plans to offer CDPD services next year.
Circuit-switched basics
Today, the most widespread option for transmitting cellular data is over the circuit-switched network, which is the technical term for the existing cellular network. The term “circuit-switched” simply means that a dedicated circuit, or channel, is established between two modems during a data call-just as a cellular voice call has a dedicated channel.
The data travels along this dedicated channel throughout the data call, until one of the modems hangs up, ending the call. The circuit-switched network is ideal for larger data transmissions, such as faxes, company files, contracts, billing documents, or data-intensive graphics and images.
In AirTouch Cellular’s case, the company charges for a circuit-switched data call at the same per-minute airtime rates as a cellular voice call, making circuit-switched data transmissions extremely cost effective
CDPD basics
A second technology for transmitting cellular data is CDPD. Recently developed by a consortium of the principal cellular carriers, the CDPD technology uses open, nonproprietary standards. This open standard gives companies the leeway to choose among a wide array of hardware options as they re-engineer their mobile work forces, and does not lock a company into a proprietary data solution. CDPD is currently available in selected geographical areas and will become available in a wide range of markets next year.
The CDPD system works by breaking data into small packets and routing the packets over idle channels of the existing cellular network to their destination. Unlike the circuit-switched system, CDPD does not require a dedicated cellular channel, or circuit, to transmit data.
Technically speaking, CDPD is a “connectionless network,” which means that a single end-to-end connection is not required, such as a modem-to-modem connection in a circuit-switched system call.
Instead, CDPD supports two standard connectionless network protocols, the Internet Protocol (IP)-which is used in today’s much debated Internet-and the Connectionless Network Protocol (CLNP). These protocols allow for data communication independent of any network hardware.
The CDPD system is ideal for transmitting short bursts of data, such as credit card authorizations, meter readings or short e-mail messages, and can provide an inexpensive means of adding an electronic messaging or dispatch capability to a company’s operations. The company will then have the advantage of both wireless voice and data communications.
Optimizing the connection
In today’s circuit-switched networks, which handle both voice and data calls, it’s important to know that data transmissions are more susceptible than voice calls to the dynamics of the cellular environment.
Common to the urban landscape are buildings, trees, hills and valleys, all of which can cause interference with the cellular radio signal. While these interferences do affect the voice connection, your conversation can continue through the mild, temporary disturbance. The same interferences during a data transmission often makes the data connection difficult. Given this unpredictable environment, it’s key to have a strong data cellular connection.
Many larger companies go for a custom cellular data solution, where the dynamics of the cellular environment are resolved during the development process. AirTouch, and other major cellular carriers regularly work with hardware and software developers to provide custom end-to-end solutions to re-engineer a company’s mobile work force.
Independe
nt mobile professionals seeking to do data-over-cellular face a different set of connectivity circumstances, which are easily resolved by acquiring the right equipment for data transfer.
AirTouch Cellular recommends that mobile professionals go for the easiest plug-and-play connection, which is known as a “direct-connect” solution. This solution includes a laptop with a built in PCMCIA (Personal Computer Memory Card International Association) Type II card slot for cellular data transfer.
You’ll also need a cellular-enhanced modem, preferably one that uses cellular specific advances, such as the AT&T Paradyne ETC (Enhanced Throughput Cellular) protocol, or Celeritas Technologies TX-CEL cellular enhancement.
Certain phones and modems also make the data connection job easier. Phone manufacturers that offer direct connect solutions are AT&T Corp., Motorola Inc., NEC America Inc., Nokia Corp., Oki telecom, Pioneer and Technophone Corp. Finally, you’ll need a data cable to connect the modem to the cellular phone.
If a laptop does not have the PCMCIA slot for a direct-connect solution, there are a number of other ways to connect your existing equipment for cellular data transmissions. Most cellular carriers offer information on alternative connectivity solutions, or with the direct-connect solution, if needed.
The new data services
In addition to adding data capabilities, U.S. cellular carriers also are developing a series of data services to enhance real-world data transfers over the circuit-switched network. The first such offerings focus on modem-to-modem connections in circuit-switched networks, such as AirTouch’s ModemConnect service.
The ModemConnect service, slated for introduction in October, solves potential connectivity problems between unlike modems by matching up the sending modem with the receiving modem, allowing each to operate at its maximum performance levels. To use the service, you simply add #3282 to the beginning of the 10-digit number you are calling.
Many U.S. cellular carriers are offering some form of modem-to-modem service, allowing cellular data users the best possible data connections over the cellular airways. In the near future, more data services will be introduced by cellular carriers to make both circuit-switched and CDPD cellular data connections fast, efficient and convenient.
And of the future? In the next year or so, stay-tuned for the unveiling of the cellular industry’s all-digital networks. In the United States, two competing standards will be available for providing digital voice and data-Time Division Multiple Access (TDMA) and Code Division Multiple Access (CDMA).
As these digital cellular technologies mature, cellular carriers will continue to support the analog circuit-switched and CDPD networks as well as the new digital cellular solutions.
Vito J. Palmieri is the director of technology for AirTouch Cellular’s Data Group. His primary focus is to help develop the regulatory and technical strategies to make cellular data increasingly easy for people to understand and use.
