The need to keep in touch—we all have it, whether for business or
personal reasons. Now you can keep in touch on the way to work or
the shopping center, from a construction site or the golf course, or in
a rental car or on your boat.
If you spend time away from your best communication tool—the
telephone—a cellular phone can add several business hours to your
week. Now you can stay in touch with your office, your customers,
or your family, even as you inch along in a traffic jam. And cellular’s
excellent audio performance ensures clear voice reception....
We discussed wireless LANs in chapter 14. Wireless technology is also used in cellular telephony and satellite networks. We discuss the former in this chapter as well as examples of channelization access methods (see Chapter 12). We also briefly discuss satellite networks, a technology that eventually will be linked to cellular telephony to access the Internet directly.
Generation Change in Cellular Systems
In Japan, mobile communications systems based on cellular technology have evolved, as illustrated in Figure 1.1. The ﬁrst-generation analog car phones were ﬁrst introduced in 1979, followed by the commercialization of the second-generation digital phones in 1993. Mobile phone subscribers have rapidly increased in number since then, owing to the liberation of terminal sales and continuous price reductions. In March 2000, the number of mobile phone subscribers outnumbered those of ﬁxed telephones.
The last decade proved to be hugely successful for the mobile communications industry,
characterised by continued and rapid growth in demand, spurred on by new technological
advances and innovative marketing techniques. Of course, when we refer to mobile communications,
we tend to implicitly refer to cellular systems, such as GSM. The plight of the
mobile-satellite industry over the last decade, although eventful, has, at times, been more akin
to an out of control roller coaster ride.
The third generation (3G) mobile communication system is the next big thing in the world of mobile telecommunications. The first generation included analog mobile phones [e.g., Total Access Communications Systems (TACS), Nordic Mobile Telephone (NMT), and Advanced Mobile Phone Service (AMPS)], and the second generation (2G) included digital mobile phones [e.g., global system for mobile communications (GSM), personal digital cellular (PDC), and digital AMPS (D-AMPS)].
Introduction to the Oracle Server Technologies
avoids these issues by formatting a report’s output as XML tags. Any client can request an XML Publisher report and (provided it has an XML parser) display the results. This is the key to distributing reports over wireless protocols to any device, such as a cellular telephone. Oracle Discoverer is an end-user tool for report generation. Oracle Reports and XML Publisher need a programmer to design the report.
SAR Distributions in a Head Model
The development of cellular telephones and mobile communication systems has led to a growing awareness of the vital role that wireless systems play in communication networks and the biological effects of EM fields on users. Since cellular hand phones are operated in close proximity to human heads while in use, there has been increasing public concern about the health effects of the human head exposed to EM energy emitted from mobile handset antennas.
PUBLIC SATELLITE NETWORKS
Satellites have been carrying communications since the early 1960s, serving as relays for voice, video, or data. They have long been dominated by the military and, in their direct broadcast form, by large television communications companies. In 1989 the Gartner Group believed that the mobile satellite industry will be one of the great growth markets of the next decadesurpassing cellular telephones and digital paging, and in the same league as personal computers.
It has been known for over one hundred years that radio can be used to keep in touch with people on the move. However, wireless communications using radio were not popular until Bell Laboratories developed the cellular concept to reuse the radio frequency in the 1960s and 1970s . In the past decade, cellular communications have experienced an explosive growth due to recent technological advances in cellular networks and cellular telephone manufacturing.
HELLO, MA? IT’S ME!
Using a cellular telephone is not much different from using a conventional one. In fact, it can even be easier because these phones contain their own small computers and have many more special features than regular phones. And the high quality of their audio makes them a pleasure to use. At ﬁrst glance, the keypad of a cellular phone may appear intimidating. Once you know what everything’s for, though, and how it works, there’s nothing to it.
BUTTONS, BUTTONS In addition to the usual twelve buttons found on a home or ofﬁce Touch-Tone phone, the handset of a...
MOBILE AND TRANSPORTABLE PHONES
To be able to place and receive telephone calls for various wireless applications — a telephone for the construction site, or on a boat, for example — you may want to consider a transportable phone. Vehicleinstalled phones used to be the primary type of cellular phone, and are still important for many users.
CAR CELLULAR TELEPHONE COMPONENTS A typical cellular phone installation for an automobile consists of four basic components: the power source, the control head, the transceiver/logic unit, and the antenna (see Figure 8.1).
INTO THE FUTURE
The technology that permits us to put telephones in our cars and in our pockets continues to evolve and provide us with new and improved services. Because there is no need for utility poles, conduit, or miles of expensive cable, cellular telephones can be located, either permanently or temporarily, wherever they are needed. This versatility gives cellular the crucial economic edge that ensures the rapid growth of this new industry. In this chapter we will look into the future of wireless telecommunications and its applications.
The use of radio-frequency communication—commonly referred to
as wireless communication—is becoming more pervasive as well as more
economically and socially important. Technological progress over many
decades has enabled the deployment of several successive generations
of cellular telephone technology, which is now used by many billions
of people worldwide; the near-universal addition of wireless local area
networking to personal computers; and a proliferation of actual and proposed
uses of wireless communications.
Development of the Personal Handyphone System in Japan
At the end of the 1980s, two cordless telephone systems, CT2 and DECT, had entered the second step of their development process. At that time, Japan had not yet developed any comparable technology; therefore work began in 1989 on a Japanese cordless standard, which has become known as the Personal Handyphone System (PHS). Disadvantages of conventional cellular telephone systems, such as high costs of infrastructure and cell-planning resulting in high communication fees, had motivated the development of a less expensive system. ...
CELLULAR PHONE EQUIPMENT
There are three parts to a cellular phone system: the cellular telephone, or cellphone; the cell site, which receives and transmits radio signals from and to your phone; and the MSC, or Mobile Switching Center, which links cellphones to established conventional telephone services. The relationship among these is illustrated in Figure 2.1.
OPTIONS AND ACCESSORIES
Cellular telephones have so many features built into them that it’s difﬁcult to think of anything more that could be added to them. Many of these features have been discussed in previous chapters, but we will explore them further here.
BATTERIES A second battery is perhaps the most-requested accessory of any portable cellphone user. It extends the time between charges while on the road, and ensures that there is always a charged battery at hand if you ﬁnd that the battery in your phone is dead.
DEALING WITH OPERATIONAL DIFFICULTIES
Cellular telephones are rugged and reliable. They have to be, since their very nature dictates that they will be banged around and subjected to extremes of heat and cold in briefcases, automobiles, and other places. They rarely fail. Most of any difﬁculties with your cellphone will arise from the conditions under which it is used and, possibly, from your initial unfamiliarity with the equipment and with cellular systems in general.
Continued advances in information technologies are enabling a
growing number of physical devices to be imbued with computing
and communications capabilities. Aircraft, cars, household
appliances, cellular telephones, and health monitoring devices all contain
microprocessors that are being linked with other information processing
devices. Such examples represent only the very beginning of what is
possible. As microprocessors continue to shrink, wireless radios are also
becoming more powerful and compact.
The generic cellular communication system, shown in Fig.l, is an
integrated network comprising a land base wire line telephone network and a
composite wired-wireless network. The land base network is the traditional
telephone system in which all telephone subscribers are connected to a
central switching network, commonly known as PSTN (Public Switching
Telephone Network). It is a digital switching system, providing: i)
Switching, ii) Billing, iii) 911 dialing, iv)l-800 and 1-900 calling features, v)...