Wireless systems - Research Paper Example

?……………… ……………… ………………. 5 May Table of Contents Page Wireless – Introduction 2 Basic Building Blocks/Components of Wireless Systems 2 a) Users 2b) Client 2 c) Network Interface Card 3 d) Medium 4 Wireless Systems 4 a) Cellular 4 b) Private Mobile Radio 4 c) Fixed wireless systems 4 d) Short range wireless systems 4 e) Broadcasting 5 Wireless System Architecture 5 History of Wireless Communication 6 Works Cited 9 Wireless - Introduction The term wireless refers to the type of communication system in which instead of a physical medium like wires, information is communicated through electromagnetic waves over a part or whole path of communication. In broader perspectives wireless communication involves number of technologies with numerous applications yet basic under laying idea behind each technology and application is to information shearing. In last couples of decade’s wireless communications, systems along with their applications and underlying technologies are among the most active area of development and enjoy the fastest growth in history. The rapid development in this regards has turned the world into a global village (Prassad, and Ruggieri 2). Basic Building Blocks/Components of Wireless Systems Since wireless communication involves number of technologies and their applications hence similar to wired communication there exist a wide range of equipment’s (both at transmitter and receiver ends) to execute communication task by propagating light or radio waves through a medium. However in border sense a wireless system consists of following primary network components. a) Users- The users of a wireless system can be anything including human beings. The users can be mobile or stationary. The basic function of a user is to initiate and terminate the use of a wireless network, making the term end-user appropriate. b) Client- The second major primary component of a wireless network is a computer device designed according to specific need, generally termed as a client. A client works on certain operating systems like as Windows XP, LINUX, or MAC OS etc. Similar to a user a client can be mobile or stationary. For mobile support applications, client devices are generally small and handy (fig.1) with display and keyboard along with a battery power backup (Geier 37). Fig.1 Wireless Devices c) Network Interface Card- Network interface card (NIC) provides an interface between a network device and a wireless network. Depending on requirements, NIC can be a part of a client or as external network adaptor as shown in fig.2. Wireless NICs are designed to meet certain form factors like Industry-Standard Architecture (ISA), Fig. 2 NICs Peripheral Component certain form factors like Industry-Standard Architecture (ISA), Peripheral Component Interconnect (PCI) and PC Card etc. These factors actually define the physical and electrical bus interface that enables the card to act as a bridge to carry communication between a computer device and wireless network (Geier 38). d) Medium- A wireless system uses a medium like air to propagate its signals (radio or light waves) from sender to receiver. Various modulation schemes like amplitude modulation (AM), frequency modulation (FM) and phase modulation (PM) are used to propagate the signal over long distances (Kennedy, and Davis 3). Wireless Systems The development of various wireless systems is a wide area of present day research. Following is a brief overview of current wireless systems. a) Cellular- Cellular wireless communication comprising 1G (AMPS, IS-41, ETACS) 2G (USDC-IS136, GSM, CDMA-IS-95), 2.5G (CDPD, GPRS, EDGE, CDMA1-IS-95B), 3G (TDS-CDMA, CDMA2000 1X, 2X) and futuristically the 4G networks is the major contributor of wireless cellular systems (Li 19). b) Private Mobile Radio- The private mobile radio (PMR) is another important category of wireless systems. Analog, digital, mesh and emerging technologies including cognitive radio and software defined radio (SDR) are important categories of private mobile wireless radio systems European standard TETRA, the US standard APCO25 and the proprietary TETRAPOL are well known examples of PMRs systems. c) Fixed wireless systems - The fixed wireless systems consist of point-to-point, point –to- multipoint and fixed mesh systems. d) Short range wireless systems- The short range wireless systems can be further divided in three different types of systems including W-LANs (like members of the 802.11 family and Zigbee), W-PANs (Bluetooth, WiMedia/UWB) and RFIDs (active and passive devices). e) Broadcasting – The broadcasting systems comprises of conventional analog and digital wireless systems and handheld mobile broadcasting systems (Webb 14). Wireless System Architecture Depending on the type of a wireless system the architecture of a wireless system can be divided into two major elements i.e. (Li 19). Radio Access points. Core and Backbone networks. In view of wide range of wireless systems and the complexity of subject few example of various wireless system architectures is given below in figs. 3, 4, and 5. Fig. 3 Fig. 4 Fig. 5 History of Wireless Communication The history of wireless communication reaches back to ancient times. In ancient times light with on/off patterns or flags were used to convey messages. Also smoke signals were also in used by Greek about 150 BC to convey messages in visual distances (Goldsmith 1). The use of light and flags were remained important medium of communication particularly for navy until the introduction of radio transmission. In 1794, Claude Chappe introduced the optical telegraphic system that remained as major medium of wireless communication till the end of 18th century. Though the first commercial telegraphic line (between Washington and Baltimore) was available in 1843 and marketing of telephone had started in 1876 because of Alexander Graham Bell invention, yet due to various physical restrains (optical) wireless communication could not took off until the discovery of electromagnetic waves and their related phenomena and modulating techniques (Schiller 8). The major breakthrough in wireless communication was achieved in 1895 when Guglienlmo Marconi first successed to demonstrate the wireless telegraphy. In 1901, first transatlantic signals were communicated. The first radio transmission was carried out in 1906 by Reginald A. Fessenden transmitted the voice and music on Christmas occasion followed by first mobile transmitter in 1911. The invention of electronic vacuum tubes by Lee DeForest and Robert von Lieben in 1906 remarkably reduced the size of transmitting and receiving antenna and made possible to transmit signals over long distances. In 1920, KDKA, the first commercial radio transmission was started from Pittsburgh. The year 1928 witnessed the first television transmission and immediately same year first transatlantic regular and news color TV services were started. In 1933, the frequency modulation technique was discovered by Edwin H. Armstrong that paved the way for modern day wireless communication (Schiller 9). The end of world war II marked number of analog wireless communication projects including A, B-Netz and Nordic Mobile Telephone (NTM) systems. The analog A- and B-Netz wireless network were carrier based on 160 MHz and popular in Germany, Austria, Netherland and Luxemburg while Denmark, Finland, Norway and Sweden – the Scandinavian countries, used 450MHz and 900MHz carrier based NMT. In 1982, in view of vision to Europe Union (EU) and new seamless developments, a pan-European mobile wireless communication standard “ Groupe Supeciale Mobile” (GSM) based on 900MHz, was founded (Schiller 10). While GSM was popular in Europe, analog Advanced Mobile Phone System (AMPS) wireless communication system working at 850MHz was equally popular in USA (Rappaport 5). In early 1990s, fully digital communication systems were introduced and few years later after a lot discussion finally GSM operating at 900MHz with 124 full-duplex channels, with international roaming, authentication and encryption features was adopted in near about 130 countries as the most popular mobile communication system. With rapid expansion in wireless networks soon it was observed that 900MHz spectrum was not sufficient to meet the need of users’ higher densities areas particularly in cities hence instead of GSM 900MHz spectrum, GSM 1900MHz spectrum was adopted for mobile communication to accommodate the users requirements (Schiller 11). The year 1998, marked the beginning of era of satellite communication with the help of Iridium Satellite System. The Iridium Satellite System “consists of 66 satellites in low earth orbit and uses 1.6GHz band for communication with the mobile phones” (Schiller 12). In THE same year through a European proposal International Mobile Telecommunications-2000 (ITM-2000) to International Telecommunication Union (ITU), GSM technology with more efficient band-width solutions was adopted as Universal Mobile Telecommunication System (UMTS). Later in view of ITM-2000 recommendations, a road map is defined to adopt a common worldwide framework of seamless wireless communication (Schiller 12). Works Cited Geier, Jim. Wireless Networks first-step. San Jose: Cisco Press, 2005. Print. Goldsmith, Andrea. Wireless Communication. London: Cambridge University Press. 2005. Print. Li, Tongtong. “Introduction to Wireless Communications and Networks.” Michigan State University, n. d. Web. 5 May 2013. Kennedy, George, and Bernard Davis. Electronic Communication Systems. Lake forest Macmillan/McGraw-Hill, 1998. Print. Prasad, Ramjee, and Marina Ruggieri. Technology Trends in Wireless Communications. Boston: ArtechHouse, 2003. Print. Rappaport, Theodore S. Wireless communication Principles and Practices. New Delhi: Dorling Kindersley (Indi) Pvt. Ltd., 2002. Print. Schiller, Jochen H. Mobile Communications. London: Addison- Wesely, 2000. Print. Webb, William. Wireless Communications: The Future. Chichester: John Wiley & Sons Ltd, 2007. Print. Read More