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Chapter 12
Wireless Networking: Voice and Data

Hello, Shreeve! Hello, Shreeve! And now, Shreeve, good night.

—The first wireless transatlantic telephone call between H.R. Shreeve, a Bell Telephone engineer at the Eiffel Tower in Paris, France and B.B. Webb in Arlington, Virginia on October 21, 1915

In 1876, Alexander Graham Bell demonstrated the telephone at the Centennial Exposition of the United States in Philadelphia, Pennsylvania. From that simple demonstration of one-way transmission over a distance of several hundred feet, the copper-based telephone network grew at an astounding rate. In 1880, Bell invented the first wireless communications system, using reflected sunlight and photoelectric selenium receivers. Using this technique, however impractical, he was able to transmit intelligible speech a distance of up to 700 feet! Bell named this invention the photophone, later renaming it the radiophone, which he described as his greatest invention [12-1] and [12-2]. AT&T continued work on the technology, extending its reach to several miles. The German Naval Command made limited use of advanced devices of this sort during World War II [12-2].

Towards the end of the nineteenth century and not long after Bell’s demonstration, a young German scientist named Heinrich Rudolf Hertz discovered the phenomenon of invisible force waves emanating for several meters around an electric spark of sufficient intensity. Classical physicists, at a loss to explain the phenomenon, theorized the existence of an unknown medium, luminiferous ether, which conducted that signal. Shortly thereafter, Guglielmo Marconi was able to transmit these Hertzian waves over several kilometers—he named the new technology Radio [12-2]. In 1886, Marconi was granted a patent for the first practical wireless telegraph, for which he shared the 1909 Nobel Prize in physics. In the meantime, Reginald Fessenden developed in 1890 wireless voice communications [12-3].

The first commercial application of radio technology was that of broadcast radio introduced in the United States in 1920. The first radio station, the Westinghouse station KDKA in Pittsburgh (PA), inaugurated service by broadcasting returns of the Harding-Cox presidential election. On July 25, 1922, the first commercial station, WBAY owned by AT&T, began broadcasting from the Long Lines building in New York City. Its first paying customer, two months later, was the Queensborough Corporation, advertising its Hawthorne Court real estate development in Jackson Heights. In the meantime, AT&T employees supplied the programming, which consisted of vocal selections, piano recitals, poetry recitations and other content that seems fairly tame by today’s standards. Among the performances was a recitation of James Whitcomb Riley’s poem “An Old Sweetheart of Mine” by Miss Edna Cunningham, the audience reaction was not recorded. [12-1]. While not an immediate commercial success, radio enjoyed U.S. market penetration of 50% of households in 1930, 90% in 1940, and 100% by 1995.

Television, while first demonstrated in 1926 by John Logie Baier, a Scottish inventor, was refined by yet other Bell Labs employees, Frederick Eugene Ives and Frank Gray. The first public demonstration in the United States of color TV took place in 1927, between Bell Labs in Whippany, New Jersey and Washington, D.C., where the audience included Secretary of Commerce Herbert Hoover. Vaudeville acts were included (again, the audience reaction was not recorded). Delayed by the Great Depression and then World War II, broadcast TV was introduced in 1946 and enjoyed success similar to that of radio [12-1]. Market penetration was estimated at 50% in 1955, 90% in 1960 and 99% in 1995. Wireless radio technology also was deployed early-on in maritime communications, or ship-to-shore telephony and telegraphy. The first terrestrial mobile application was a one-way system employed in police radio dispatch trials in 1921 at the Detroit Police Department [12-4] and [12-2].

The wireless industry has experienced exponential growth over the last decade, growth that is expected to continue at a pace unprecedented in the history of communications. According to the ITU, the 1994 U.S. market size was (US$) $11 billion; Europe, $10 billion; Japan, $9.5 billion and South-East Asia, $4.5 billion. Some estimates place the number of wireless users at 100 million by the year 2010 [12-5].

While cellular voice accounts for the vast majority of this market, a plethora of new technologies recently have emerged with a broad set of new applications. The technologies discussed in this section include Trunk Mobile Radio (TMR), paging, cordless telephony, Wireless Office Telecommunications Systems (WOTS), Cellular, Wireless LANs, Wireless Local Loop (WLL), Low Earth Orbiting Satellites (LEOs), Personal Communications Services (PCS), and Personal Digital Assistants (PDAs). Within each of these technology/application categories there exist a number of specific technologies for discussion. Additionally, each technology can support some combination of voice, data, facsimile, video, and image applications.

Wireless is about more than being unplugged or untethered. Wireless, in full form, speaks to a fundamentally different way of working and living. Wireless communications adds the element of mobility, thereby removing the constraints of constant attachments to a physical space such as an office building, school, hospital, or home. Yet, wireless communications technologies are relegated to niche applications and likely will be for quite some time. For many applications, wireless just can’t compete with wired networks. The limitations of wireless and the underlying reasons will be discussed in this chapter. Theodore Vail, twice president of AT&T (1880s and early 1900s) summed it up when he said: “The difficulties of the wireless telegraph are as nothing compared with the difficulties in the way of the wireless telephone” [12-2]. While wireless telephony may have been quite a trick in those days, it is nothing compared with wireless data communications.

Wireless Defined

Wireless, quite simply, refers to communications without wires. While microwave and satellite communications are without wires, those technologies generally are considered to be high-speed, network backbone, or access technologies which are either point-to-point, point-to-mutipoint or broadcast in nature (see Chapter 3 for discussion of the principles and characteristics of radio transmission). In the context of this discussion, wireless technologies are local loop or local in nature and are application- and service-oriented, rather than being transport-oriented.


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