دانلود کتاب Wireless Personal Communications: Trends and Challenges

"Well informed people know it is impossible to transmit the voice over wires, and that were it possible to do so, the thing would be ofno practical value. " from an editorial in the Boston Post -1865 Fortunately for the telecommunications industry, the unknown author of the above statement turned out to be very mistaken indeed. Even as he spoke, Alexander Graham Bell was achieving the impossible, with a host of competing inventors close behind. The communications revolution which ensued has changed the way in which we live and work, and the way in which we view the world around us. Wired telephone lines now encircle the globe, allowing instantaneous transmission of voice and data. Events from Times Square to Red Square are now as accessible as events on the local courthouse lawn. The advent of wireless communications has extended Bell's revolution to another domain. Personal communications promises voice, data and images which are accessible everywhere. Although predictions are dangerous, a look back over the last decade reveals spectacular growth. In the United States alone, there are now over 50 million cordless phones in use throughout the country -at least one cordless phone for every 3 households - and nearly 20 million pocket pagers. U. S. Cellular telephone service, launched commercially in 1984, has experienced 30-40% annual growth rates despite a sluggish economy.