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Cellular Offering Social-Economic Benefits for Mobile Around World.

Cellular Offering Social/Economic Benefits for Mobile Around World

Advancing technology has made possible a more efficient use of the sharply limited radio frequency spectrum. This basis improvement is the central concept on which I will discuss the future and the economics of mobile services. This basic improvement and revolutionary technology is called cellular. However, it would be almost impossible for me to strictly limit my discussion of cellular to only mobile services. Therefore, I will discuss the completeness of cellular as a total communications systems with the primary focus on the "mobile' applications of this new technology.

Cellular telephony is a combination of ultra-high-frequency (UHF) radio transmission and advanced, sophisticated computer technology. It has received its impetus for growth worldwide by computer developments that have reduced computer size and costs, and facilitated distribution of computerized switches throughout the cellular radio system.

In a cellular system, a narrow frequency band in the 800 MHz range is used to provide a private, two-way talking path from a fixed base radio station to a mobile (vehicle-mounted), portable (hand-carried), or fixed location telephone set. Each of these two-way talking paths is called a channel. Another feature of the cellular system is the limited transmitter power of the base radio station. In normal mobile radio telephone systems, an attempt is made to use enough transmitter power to cover the greatest distance or "range' of coverage possible. Under certain conditions, distances of 50 to 75 miles are not uncommon. However, the frequency reuse concept of cellular systems precludes the use of such large areas of coverage.

With the limited transmitter power, the range, or area covered by the radio signal, is controlled so as to create a "cell' of the desired size, usually less than 25 miles in radius, which will permit the same frequencies to be reused without great geographic separation. Cellular provides enhanced spectrum utilization through the capability to reuse frequencies in cells that are far enough removed from each other by terrain or by distance within the system. This also provides a means to grow cells continuously for system expansion and growth. It is this combination of small cells plus 624 separate, private talking paths which gives the cellular systems its capacity to provide the first time in the history of mobile radiotelephone systems, theoretically unlimited telephone service for subscribers.

Wider Bandwidth Gives Higher Quality

A central switching unit provides the interconnection to any public switched telephone network, thus enabling the cellular user to be connected to any distant subscriber worldwide who is reachable from a conventional wireline system. The voice quality is as good as or better than existing landline telephone systems. This high quality results from cellular radio channels having wider bandwidth than conventional wireline cables. The central switching unit also performs a "hand-off' or reassignment from one cell to another for a mobile user who is moving across the cell boundaries while talking. Hand-off occurs with no break or interruption in the conversation even though a new private channel is always assigned during this process. This inherent characteristic of cellular is unequalled in any other wireline or mobile radio telephone system available today.

Each cellular system is composed of three major components: base station (cell site); electronic exchange (central computerized switcher); and talking equipment (mobile, portable or fixed station telephone sets).

With the exception of the electronic exchange (EX), the number of each of these components will vary when the size of the particular system.

The base station or cell site provides the radio transceivers and control features for each cell in the system. The number of cells is determined by the size and topography of the area to be covered by the system. Of course, the tower structure and antennas are also part of the base station. Antennas may be omnidirectional or, in cases where specific areas are to be covered without interference to other areas, they may be highly directional. Signaling, channel assignment and monitoring are some of the control functions of the base station.

All of the base stations are connected to a central computerized switcher called the electronic exchange (EX) by either cable or microwave. This highly sophisticated switch performs many of the functions which set the cellular system apart from all other types of mobile telephone service. Besides the usual switching function of connecting the cellular user to another cellular user, the EX monitors the signal levels of all units from information forwarded from the base site, hereby enabling it to perform the hand-off from one cell to another when required. The EX also records and stores subscriber billing information and, from its own data files, is able to verify and either permit or refuse access to the system to prevent unauthorized use. Maintenance diagnostic routines, some automatic, some under the direction of a technician, are performed by the EX in order to assure a high state of reliability within the system.

There are currently two basic types of talking equipment available which are used in the cellular wireless telephone system. The first is a mobile unit which is usually mounted in a vehicle (it could also be a boat or ship) and is connected to the battery supply of that vehicle for its power source. The second type, a portable instrument, is about the size of a normal telephone handset and is powered by self-contained batteries which are recharged during a non-use time (such as overnight) by a unit power from normal AC house current. This instrument may be carried by an individual during daily activities to provide instant telephone communications. It also may be used in an automobile, boat or ship.

Development of a fixed location talking set is underway to provide an instrument which can be used just as a wired telephone set is used today. It would operate as the portable and mobile sets operate, but would be fastened securely to prevent moving it around. This is intended for applications where mobility is not a requirement.

Inherent Advantages of Digital Features

Since cellular systems have integrated computerized switching functions, it follows that cellular systems can supply digital features that are not available with analog-only wireline or radio systems. In cellular designs for the US, equipment suppliers are providing a 30 kHz channel bandwidth. Wherever that bandwidth can be preserved by trunking via microwave, satellite or high-quality cable, an alternative for newer digital imaging services or other data transmission is feasible.

The majority of data transmission today uses existing wireline company media. The subscriber's choices today are limited. He must select either a low-speed, 1,200-baud, dial-up media, and pay line cost on a per-minute-of-usage basis, or he may select a high-speed, 9,600-baud, dedicated conditioned line media which is leased on a 24-hour-per-day monthly basis.

This leaves the market open for a demand high-speed service. Cellular has the potential of providing a 9,600-baud data media on a per-minute-of-usage basis. Further, the rate structure could be designed to attract usage during the low-activity night hours.

The technical implementation of 9,600-baud transmission via the cellular media is the same as via the wire media. A modem is installed at the terminal and another at the computer. These devices are able to make use of the cellular path's wider bandwidth, thus passing eight times more data than the standard unconditioned wireline dial-up path. The 9,600-baud modem exists today and an experimental demonstration of this capability was performed by the Federal Bureau of Investigation in Washington, D.C. Both of the modems must be stationary during operation.

High Efficiency for Data Services

The data transmission capabilities of cellular are limited only by the design of the terminal equipment. IBM has contracted with Motorola to design and build a special terminal for use by its field engineers. No voice will be transmitted. The dispatch and acknowledge information will be transmitted via the cellular data path between the field engineer's terminal and the central dispatch computer. This system represents an efficiency gain over the voice system of 1,500 to 1.

Extensive research into comparative costs for conventional wireline telephone systems covers an extremely wide range in total cost per subscriber. The density of the population, topography, climate and wage rates are some of the variables which affect the cost.

The Rural Electrification Administration (REA), a branch of the US Department of Agriculture which provides funding for rural electric and telephone service, indicates that the latest average cost estimate to provide a rural subscriber with wireline service in the US is $2,500. In addition to the initial cost, there are extensive maintenance costs associated with poles, cables, terminals, connecting devices, fuses, inside wiring, handset and mounting cords. All are subject to deterioration, from use and exposure to climatic conditions, which result in numerous service interruptions.

The costs for the existing mobile radio system in the US is between $2,500 and $3,000 per subscriber. This cost is similar to rural wireline cost but the mobile radio maintenance costs are minimal. The mobile radio systems are, however, limited because of the grade of service and system capacity. They are not a suitable alternative for rural wireline service.

A cellular system, because of its unitized and prefabricated design, can be ordered, installed and placed in service in a period of six to nine months. With a cellular system, there is no necessity for engineering and construction of a cable distribution system.

The cost comparison for a rural wireline system versus a rural wireless cellular system at today's costs are in favor of cellular. For example, a rural cellular system designed for 1,000 subscribers, dispersed over an area 32 kilometers wide and 80 kilometers in length, can be constructed for $800,000, US costs. (This is an excellent grade of service; 95 percent assurance of available channels at the busiest hour of the day-- the average for the US.) This eqates to $800 per subscriber for the infrastructure costs. Add to this the telephone set cost of $1,500 for a total amount of $2,300 per subscriber.

Prices Will Drop

There are presently more than a dozen major international telecommunications manufacturers gearing up to manufacture, sell and install cellular systems all over the globe. Industry spokespeople and cellular equipment manufacturers have indicated that telephone set prices can be expected in the $500 range as the US systems begin operation and the market for telephone sets increases. This would bring a total cellular wireless telephone system cost per subscriber down to $1,300 for the .05 grade of service in the next year.

There is also an additional significant cost advantage which accrues to the cellular system--there are no (or negligible) yearly maintenance costs associated with cellular systems. Also, cellular is a fully automatic, wide area, high-capacity communications system. It employs state-of-the-art digital switching and base site equipment. The EX can also interconnect to any type of wireline switching system.

A further benefit resulting from the new technology of cellular wireless telephone is the greatly reduced requirement for skilled technical staff. Since there is no "outside plant' involved, there is no need for linemen, cable splicers and repairmen to maintain the subscriber loop portion of the system. With the solid-state electronic components and their relatively failure-free performance in the EX and base stations, a system with up to 10 cells and 10,000 subscribers could be maintained with one or two technicians, greatly reducing the drain of skilled technical people in any country.

The social and economic benefits of a cellular system are many. The areas of health, education, welfare, weather forecasting and warnings and public safety would benefit greatly from cellular. Areas without telephone service are generally unable to provide more than a minimum level of basic services to its citizens. For example, a cellular system could bring to an area the ability to summon medical help, transmit medical information between the on-site person and a hospital or other information sources. It could even transmit electrocardiograms or other bio-medical information directly to analysis centers of laboratories. At times when public safety is threatened, it would be invaluable to have a reliable, available means to call police, the fire department, the weather service or other help to assist the local citizen in need.

One of the basic ingredients in the development of any nation or area is the easy exchange of information. The mere act of communicating with those around you always enhances perspective and generates ideas. With good telephone service, this exchange becomes a way of life and the development of cultural and educational segments of national life follows. Cellular telephony has no exclusive in this development; it is simply a more direct, less costly and expedient way to obtain these benefits.

Just as the social development depends on good communications, the economic growth is absolutely dependent on good telecommunications. With improved telephone service, rural merchants, farmers and livestock owners are able to place orders, sell products, make selective purchases and stimulate trade just as well as their urban counterparts. Business and agriculture can branch out to areas beyond their former territories, since they would be in direct contact with the local managers for day-to-day decisions. Improved efficiency through timely and reliable telephone service allows the business community to apply more of their resources toward expansion.
COPYRIGHT 1984 Nelson Publishing
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Copyright 1984 Gale, Cengage Learning. All rights reserved.

Article Details
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Author:Hagel, C.
Publication:Communications News
Date:Feb 1, 1984
Previous Article:Cellular Radio Ushers in Revolutionary Changes for Servicing Business User Needs.
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