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Chapter 55
Developing a Cost-Effective Strategy for Wireless Communications

Sami Jajeh

Most organizations have some mobile field activities involving sales representatives, field service technicians, telecommuting employees, traveling managers, route-based personnel, or even mobile health care providers. Organizations with significant numbers of mobile field activities require a well- synchronized exchange of information between central information systems and mobile users.

Many organizations are investing in portable computers and software to provide mobile users with the tools they need to accomplish their daily tasks. Some organizations have begun to look at emerging wireless technologies to further enhance communications and streamline information exchange by providing anytime, anywhere access.

Automating business processes through wireless technology offers organizations many benefits, including improved productivity and increased competitive advantage. To achieve these benefits, organizations must thoroughly consider several implementation issues that fall into three broad categories:

  Communications architecture and access methods.
  Application appropriateness.
  Wireless service products.

This chapter aims to help organizations develop a cost-effective wireless communications strategy that meets the needs of mobile and remote workers. Following an overview of wireless network technology and service providers, it discusses each of the three categories of implementation issues and the advantages and disadvantages of the various options within them.

WIRELESS NETWORK TECHNOLOGIES AND SERVICE PROVIDERS

The following sections discuss major network technologies and service providers; they are not intended to provide an exhaustive list of current technologies and players. There are two prevalent technologies for wireless applications:

  Circuit-switched networks.
  Packet data networks

Circuit- Switched Networks

Circuit-switched networks involve establishing a dedicated connection (or circuit) between two points and then transmitting data over the connection, much like a typical telephone conversation. They can be either analog or digital.

Analog Circuit-Switched (Cellular) Networks. Two- way analog circuit-switched cellular (CSC) technology has existed since the advent of cellular phones. To use CSC service, the user requires a cellular phone with a cellular modem. Sending wireless data over a circuit- switched cellular connection offers several advantages, including:

  Wide on-street coverage and availability.
  Suitability for sending and receiving large data files such as long E-mail messages or reports.
  Per-minute (as opposed to per-packet) charges.
  Implementation through standard communications software and a modem attached to a cellular phone.

The disadvantages of using circuit-switched cellular technology include:

  Increased relative cost of sending short messages, because call setup time may become a large percentage of cost.
  Security concerns involving unencrypted files.
  Lack of cellular error-correction or enhancement standards.

Although questionable reliability and poor throughput are often cited as disadvantages of analog circuit- switched cellular connections, the availability of new technology from several vendors, including AT&T, Celeritas Technologies Ltd., Microcom Corp., Motorola, and ZyXEL, is rapidly changing this perception. These mature technologies allow organizations to use analog cellular modem technology to build and deploy enterprisewide dial-up based applications.

Digital Circuit-Switched (Cellular) Networks. Digital communications technology is inherently more reliable for sending data than is analog technology. Examples of digital circuit-switched wireless network implementations in the US are code division multiple access (CDMA) and time division multiple access (TDMA). Because the availability of both CDMA and TDMA is limited, it will be some time before most US organizations will be able to take advantage of digital circuit- switched technologies for wireless data applications.

Packet Data Networks

Packet data networks have been designed for effective and reliable transfer of data rather than voice. They use a method that is comparable to sending a document one page at a time. The document is first broken into pages, and each page (or packet) is sent in its own envelope. The network determines the most appropriate transmission path, and once each page reaches its destination, the document is reassembled (if appropriate).

Packet data networks use radio frequency channels to connect the portable computing device to a network backbone and, ultimately, to the company’s host system. The major networks (e.g., Ardis and RAM Mobile Data) use packet radio technology. Packet cellular technology (e.g., cellular digital packet data, or CDPD) is now emerging.

Packet Radio Technology. The two major wireless packet data networks are Ardis and RAM.

Ardis. A nationwide, packet radio network owned by Motorola and IBM, Ardis covers 80% of the US population. Transmitters in the 400 largest metropolitan areas are networked through dedicated land-based lines, although dial-up and radio frequency (RF) connections are also supported. Ardis supports fully automatic roaming. In addition to on-street and in-vehicle coverage, Ardis is said to offer more reliable in-building coverage than do other two-way wireless networks. Pricing depends on the application and is based on both flat-rate and usage charges.

RAM Mobile Data. The RAM Mobile Data network is the result of a business venture between BellSouth Enterprises and RAM Broadcasting Corp. to provide wireless transport for messaging services and products. Commercial service currently is available in more than 6,000 cities and towns. RAM uses the Mobitex architecture for wireless packet data communications originally developed in Sweden and currently in its fourteenth version. RAM’s network was designed for message capability with inherent roaming, store-andforward, and broadcast capabilities.


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