1.0 Introduction
Cellular communications has experienced explosive growth in the past two decades. Today millions of people around the world use cellular phones. Cellular phones allow a person to make or receive a call from almost anywhere. Likewise, a person is allowed to continue the phone conversation while on the move. Cellular communications is supported by an infrastructure called a cellular network, which integrates cellular phones into the public switched telephone network.
The cellular network has gone through three generations. The first generation of cellular networks is analog in nature. To accommodate more cellular phone subscribers, digital TDMA (time division multiple access) and CDMA (code division multiple access) technologies are used in the second generation (2G) to increase the network capacity. With digital technologies, digitized voice can be coded and encrypted.
Therefore, the 2G cellular network is also more secure. The third generation (3G) integrates cellular phones into the Internet world by providing high speed packet-switching data transmission in addition to circuit-switching voice transmission. The 3G cellular networks have been deployed in some parts of Asia, Europe, and the United States since 2002 and will be widely deployed in the coming years.
This chapter gives an introduction to cellular networks and its harmful effects to animals. The rest of this chapter is organized as follows: The second chapter deals with literature review which introduces different basic cellular network concepts, and the third chapter describes the harmful effects of cellular network to animals. Conclusion and recommendations are drawn based on the findings of this work.
1.1 Evolution Of Cellular Networks
Cellular systems became popular because of radio-frequency reuse, which allows more cell phone users to be supported. The cellular concept was first used in the AMPS in the United States. As a first generation of cellular systems, AMPS is a FDMA-based analog system. The 2G of cellular systems uses digital technologies. It is clear that the 3G of cellular systems will be CDMA-based. However, the GSM community is developing WCDMA to be backward compatible with GSM while the CDMA community tries to evolve CDMA into CDMA2000. Currently researchers are studying technologies for Beyond 3G (B3G) or fourth generation (4G) networks.
In the late 1970s and early 1980s, AT&T Bell Laboratories developed the AMPS, which was the first-generation cellular system used in the United States (Rappaport, 2002; Young, 1979). It was first deployed in Chicago and Washington, DC, then in all the major U.S. cities. Currently it is still used in many rural areas.
To overcome the limited capacity of AMPS, especially in large cities, D-AMPS (IS-54) was developed in the early 1990s (EIA/TIA, 1990). D-AMPS inherited a lot of features from AMPS. Specifically, in D-AMPS, the same AMPS allocation of frequency spectrum is used, and each channel is still 30 kHz wide. However, in D-AMPS, a 30- kHz channel can be shared by three users through the 2G TDMA digital technology.
GSM is a 2G system developed to solve the incompatibility problem of different first-generation systems in Europe, Black, (1999); Mouly & Pautet, (1992); Rahnema, (1993). It is now widely deployed around the world including in the United States. GSM was first developed for Europe in the 900-MHz band (GSM 900), then expanded to the 1800-MHz band (1710—1880 MHz), which is named DCS 1800, and later renamed to GSM 1800.
A SIM card can be inserted into any cell phone to make the phone usable. The high-speed data transmission is the main development focus. Now researchers are developing technologies for B3G or 4G networks (Technologies Beyond 3G, n.d.). It is expected all the 4G network elements are digital and the entire network is packet-switched. 4G networks will integrate wireless local area networks (LANS) such as IEEE 802.11 and Bluetooth with wide area cellular networks. The data transmission rate of 4G communications will be much higher than 3G, at 20 to 100 Mbps in mobile mode in recent times.
1.2 Meaning And Definition Of Cellular Network
A cellular network is a radio network distributed over land areas called cells, each served by at least one fixed-location transceiver known as a cell site or base station. When joined together these cells provide radio coverage over a wide geographic area. This enables a large number of portable transceivers (e.g., mobile phones, pagers, etc.) to communicate with each otherand with fixed transceivers and telephones anywhere in the network, via base stations, even if some of the transceivers are moving through more than one cell during transmission.
Cellular networks offer a number of advantages over alternative solutions:
- Increased capacity
- Reduced power use
- Larger coverage area
- Reduced interference from other signals
An example of a simple non-telephone cellular system is an old taxi driver's radio system where the taxi company has several transmitters based around a city that can communicate directly with each taxi.
1.3 Aims And Objectives
The aim of this study is to carried out a research on cellular networks and its harmful effects on animals.
The objectives of this study include:
- To take a critically look on cellular network.
- To examine the harmful effects of cellular network.
- To look at the importance of cellular network and;
- To suggest possible ways to minimize these effects
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