Future Trends of Mobile and Personal Communications Evolution of Mobile Radio Communications

FUTURE TRENDS OF MOBILE AND PERSONAL COMMUNICATIONS (Invited Paper) Theodore S. Rappaport Mobile & Portable Radio Research Group Bradley Department of Electrical Engineering Virginia Tech Blacksburg, VA 24061-0350 email: [email protected] This tutorial paper provides an overview of the fundamental concepts used in cellular radio communications, and illustrates the likely evolution and growth of the personal communications field. This paper also summarizes some of the most popular wireless standards used throughout the world, and has been adapted from [1]. 1. Evolution of Mobile Radio Communications The ability to communicate with people on the move has evolved remarkably since Guglielmo Marconi first demonstrated radio's ability to provide continuous contact with ships sailing the English channel. That was in 1898, and since then, new wireless communications methods and services have been embraced by citizens throughout the world. Particularly during the past ten years, the mobile radio communications industry has grown by orders of magnitude, fueled by digital and RF circuit fabrication improvements, new large-scale circuit integration and other miniaturization technologies which make portable radio equipment smaller, cheaper, and more reliable. Digital switching techniques have facilitated the large scale deployment of affordable, easy-to-use radio communication networks. This trend will continue at an even greater pace during the next decade. Wireless communications is enjoying its fastest growth period in history, due to enabling technologies which permit miniaturization, digital signal processing, networking, and switching. Historically, growth in the mobile communications field came slowly, and in the past was coupled closely to technological improvements which did not come about easily. The ability to provide wireless communications to an entire population was not even conceived until Bell Laboratories developed the cellular concept in the 1960's and 1970's [2], [3], [4]. With the development of highly reliable, miniature, solid-state radio frequency hardware in the 1970's, the wireless communications era was bom. The recent explosion in cellular radio and personal communication systems throughout the world is directly attributable to new technologies of the 1970's, which are mature today. The future growth of consumer-based mobile and portable communication systems will be tied more closely to radio spectrum allocations and regulatory decisions which affect or support new or extended services, as well as to technology advances in the signal processing, access, and network areas. The following market penetration data show how wireless communications in the consumer sector has grown during the past several decades. Figure 1 illustrates how mobile telephone has penetrated our daily lives compared with other popular inventions of the 20th century. Figure 1 is a bit understated, since it does not consider non-telephone mobile radio usage, such as paging, amateur radio, dispatch, citizens band (CB), public service, cordless phones, or terrestrial microwave radio systems. In fact, in late 1990, licensed non-cellular radio systems in the U.S. had over 12 million users, more than twice the U.S. cellular user population at that time [5]. Figure 1 shows that the first 35 years of mobile telephone saw little market penetration due to high cost and the technological challenges involved, and illustrates how in the past decade, cellular telephone has been accepted by consumers at rates which are comparable to the television, the video cassette recorder (VCR), and cable television. · 2. Examples of Mobile Radio Systems Mobile radio transmission systems may be classified as simplex, half-duplex or full-duplex. In simplex systems, communication is possible in only one direction. Paging systems, in which messages are received but not acknowledged, are simplex systems. Half-duplex radio systems allow two-way communication. but use the same radio channel for both transmission and reception. This means that