IJCSC Volume 5 • Number 2 July-Sept 2014 pp. 61-70 ISSN-0973-7391 Study of Wireless Communication Technologies: Bluetooth, WI-FI, Cellular and WiMAX 1Omendri kumari and 2Dr. Sanjay Kumar 1,2School of Engineering & Technology, Jaipur National University, Jaipur [email protected], [email protected] ABSTRACT A rush forward of research activities in wireless communication has been seen in last decade. There are new points of view on how to communicate effectively over wireless channels from this research drive. The purpose or aim of this paper is to study the basics as well as new research developments. We studied four types of wireless communication technology that are Bluetooth, Cellular, Wi-Fi and WiMAX in this paper. we have described architecture and working of these technologies to understand them easily. we have concluded which one is the best through comparative study and analysis. KEYWORDS: WIRELESS COMMUNICATION, BLUETOOTH, WI-FI, WIMAX, CELLULAR. 1. INTRODUCTION With the rapid development of communication technologies, future wireless communication systems should support voice, data, audio/video, multimedia, interactive games, and Internet traffic. A potential solution for this is to make the wireless communication network and the broadcasting network converge to form a unified convergence network. Wireless communications is, by any measure, the fastest growing segment of the communications industry. [1] As such, it has captured the attention of the media and the imagination of the public. Cellular phones have experienced exponential growth over the last decade, and this growth continues unabated worldwide, with more than a billion worldwide cell phone users projected in the near future. Indeed, cellular phones have become a critical business tool and part of everyday life in most developed countries, and are rapidly supplanting antiquated wire line systems in many developing countries. The vision of wireless communications supporting information exchange between people or devices is the communications frontier of the next century. This vision will allow people to operate a virtual office anywhere in the world using a small hand held device - with seamless telephone, modem, fax, and computer communications. Wireless networks will also be used to connect together palmtop, laptop, and desktop computers anywhere within an office building or campus, as well as from the corner cafe. In the home these networks will enable a new class of intelligent home electronics that can interact with each other and with the Internet in addition to providing connectivity between computers, phones, and security/monitoring systems. Such smart homes can also help the elderly and disabled with assisted living, patient monitoring, and emergency response. Figure 1. Communication system Figure 1 explains all components of a basic communication as, The source originates a message, which could be a human voice, a television picture or data. The source is converted by an input transducer into 61 IJCSC Volume 5 • Number 2 July-Sept 2014 pp. 61-70 ISSN-0973-7391 an electrical waveform referred to as the baseband signal or message signal. The transmitter modifies the baseband signal for efficient transmission. The transmitter generally consists of one or more of the following subsystems: a pre-emphasizer, a sampler, a quantizer, a coder and a modulator. The channel is a medium through which the transmitter output is sent, which could be a wire, a coaxial cable, an optical fiber, or a radio link, etc. Based on the channel type, modern communication systems are divided into two categories: wireline communication systems and wireless communication systems. The receiver reprocessed the signal received from the channel by undoing the signal modifications made at the transmitter and the channel. The task of the receiver is to extract the message from the distorted and noisy signal at the channel output. The receiver may consist of a de-modulator, a decoder, a filter, and a de-emphasizer. The receiver output is fed to the output transducer, which converts the electrical signal to its original form. Transmitters and receivers are carefully designed to overcome the distortion and noise. The Goal of Physical layer Communication System is to transmit information accurately and efficiently (power and spectrum). Usually, this data acquisition system uses a controller AT89C51, Analog to Digital converter ADC0831, and various communication modules. Some software modules also used to make data acquisition efficient and flexible. Bluetooth is a wireless technology IEEE 802.15.1 standard for exchanging data over short distances by using short-wavelength UHF radio waves in the ISM band from 2.4 to 2.485 GHz from fixed and mobile devices, and building personal area networks (PANs). Wi-Fi is a technology that allows an electronic device to exchange data or connect to the internet wirelessly using microwaves in the 2.4 GHz and 5 GHz bands using IEEE 802.11 standards. A cellular network or mobile network is a wireless network distributed over land areas called cells, each served by at least one fixed-location transceiver, known as a cell site or base station. In a cellular network, each cell uses a different set of frequencies from neighboring cells, to avoid interference and provide guaranteed bandwidth within each cell. Last one technique WiMAX (Worldwide Interoperability for Microwave Access) is a wireless communications standard designed to provide 30 to 40 megabit-per-second data rates. Wireless networking is also a significant challenge. The network must be able to locate a given user wherever it is amongst millions of globally-distributed mobile terminals. It must then route a call to that user as it moves at speeds of up to 100 mph. 2. COMMUNICATION METHODS 2.1 Analog versus Digital Communication An analog or analogue signal is any continuous signal for which the time varying feature (variable) of the signal is a representation of some other time varying quantity, i.e., analogous to another time varying signal. For example, in an analog audio signal, the instantaneous voltage of the signal varies continuously with the pressure of the sound waves. It differs from a digital signal, in which a continuous quantity is represented by a discrete function which can only take on one of a finite number of values. An analog signal uses some property of the medium to convey the signal's information. For example, an aneroid barometer uses rotary position as the signal to convey pressure information. In an electrical signal, the voltage, current, or frequency of the signal may be varied to represent the information. Any information may be conveyed by an analog signal; often such a signal is a measured response to changes in physical phenomena, such as sound, light, temperature, position, or pressure. The physical variable is converted to an analog signal by a transducer. For example, in sound recording, fluctuations in air pressure (that is to say, sound) strike the diaphragm of a microphone which induces corresponding fluctuations in the current produced by a coil in an electromagnetic microphone, or the voltage produced by a condenser microphone. The voltage or the current is said to be an "analog" of the sound. 62 IJCSC Volume 5 • Number 2 July-Sept 2014 pp. 61-70 ISSN-0973-7391 Figure 2. Analog communication Data transmission, digital transmission, or digital communications is the physical transfer of data (a digital bit stream) over a point-to-point or point-to-multipoint communication channel. Examples of such described channels are as copper wires, optical fibres, different wireless communication channels, storage media and computer buses. The data are represented as an electromagnetic signal, such as an electrical voltage, radiowave, microwave,or infrared signal. While analog transmission is the transfer of a continuously varying analog signal, digital communications is the transfer of discrete messages. The messages are either represented by a sequence of pulses by means of a line code (baseband transmission), or by a limited set of continuously varying wave forms (passband transmission), using a digital modulation method. The passband modulation and corresponding demodulation (also known as detection) is carried out by modem equipment. According to the most common definition of digital signal, both baseband and passband signals representing bit-streams are considered as digital transmission, while an alternative definition only considers the baseband signal as digital, and passband transmission of digital data as a form of digital-to-analog conversion. Figure 3. Digital Communication 2.2 Half duplex versus Full Duplex In a half duplex (HDX) transmission, a data packet is sent by one system and received by the other. Another data packet cannot be sent until the receiving system sends an acknowledgment back to the sender. In a full duplex (FDX) transmission, both the sending and receiving systems communicate with each other simultaneously; in other words, both modems can send and receive data at the same time. This means a modem can be receiving a data packet while acknowledging the receipt of another. Figure 4. Half Duplex versus Full Duplex 63 IJCSC Volume 5 • Number 2 July-Sept 2014 pp. 61-70 ISSN-0973-7391 3. COMMUNICATION TECHNIQUES 3.1Bluetooth Bluetooth, also known as the IEEE 802.15.1 standard is based on a wireless radio system designed for short-range and cheap devices to replace cables for computer peripherals, such as mice, keyboards, joysticks, and printers. This range of applications is known as wireless personal area network (WPAN). Bluetooth attempts to provide significant advantages over other data transfer technologies, such as IrDA and Home RF, vying for similar markets. Despite comments from the Bluetooth SIG indicating that the technology is complementary to IrDA, it is clearly a competitor for PC-to-peripheral connection. IrDA is already popular in PC peripherals, but is severely limited by the short connection distance of 1 m and the line-of-sight requirement for communication. This limitation eliminates the feasibility of using IrDA for hidden computing, where the communicating devices are nearby but not visible to one another.