Wireless Communication - Case Study Example

Wireless communication is the fastest growing segment of the communications industry. Wireless technology has brought about revolution in how people work and communicate. This technology has not only eliminated the cable connecting the desktop computers, it has also facilitated the use of handheld PDAs, WAP, GPRS and 3G in mobile phones and WiFi and WiMax in broadband. This paper will trace the history of wireless communications and then compare the GSM technology with CDMA technology. The history of first wireless networks dates back to the pre-industrial age when information was transmitted over line-of-sight distances using smoke signals, torch signaling, flashing mirrors, or semaphore flags (Goldsmith, 2005). Complex messages could be conveyed through these rudimentary signals. These communication networks were replaced by the telegraph and then by telephones, which was patented by Alexander Graham Bell in 1876 (JPL, 1995). In 1895 came the radio technology that advanced rapidly where transmission could be done over larger distances with better quality and cheaper costs. For many years wireless and radio were used to describe the same thing – the radio was the American version of the British wireless (JPL, 1995). Radio technology was initially called ‘wireless technology’ which was further shortened to ‘wireless’ (White, 2003). This technology was applied where regular telephones lines were unreliable and impractical. The next stage was the development of the broadcasting of audio messages simultaneously to multiple locations initially using the dots-and-dashes of the telegraphic code and then the full audio. The receiver was called wireless because there were no wires linking to the transmitting station. As the transmitting station radiated electromagnetic waves, it was called radio. After the invention of the transistor came the development of integrated circuits which paved the way for miniaturization of electronic systems. As early as 1860, James Clerk Maxwell predicted the existence of radio waves and in 1886 H D Hertz demonstrated the variations of electric current could be projected into space in the form of radio waves similar to those of light and heat (Bellis, 2006). In 1901 radiotelegraph service was started between five Hawaiian Islands. In 1903 an exchange of greetings was done through this service between President Theodore Roosevelt and King Edward VII (Bellis). In 1905 the Russo-Japanese war was reported through the wireless. In 1906 the US Weather Bureau tried notifying the weather conditions through this technology. Continued advances in micro-electronic circuits led to the rapid development of mobile and personal communications system. This provided freedom of movement to the users and eliminated the ineffective calls experienced by the fixed telephony. Cellular telephone systems created a worldwide wireless revolution. Cellular systems were initially designed for mobile terminals placed inside vehicles with the antennas mounted on the roof of the vehicle (Goldsmith). Today it has evolved to support lightweight hand held mobile terminals which can operate from within or outside the buildings and while walking or driving. The first generation of wireless systems used analog communications since they were designed in 1960s before digital communications came into existence. Within a few years the number of users increased to such an extent that dropped calls and network busy signals became common. To accommodate more calls the digital wireless technology was introduced which was cheaper, faster, smaller and required less power. Voice quality was better due to error correction coding. Digital systems have higher capacity since they use more efficient techniques to share the cellular spectrum. In the cellular system there are two competing network technologies. The first is the GSM cellular telephone system, which was introduced in Europe in early 1990s. GSM stands for Groupe Special Mobile but was later modified as Global System for Mobile communication. The second is the Code Division Multiple Access (CDMA) and different service providers any one of these. The two systems represent different systems of sharing of the radio spectrum for communication (Naavi, 2004). Understanding the difference between the two technologies would help to decide which carrier to choose. Wireless communications became widespread in 1980s after the advances in semi-conductors that made small handsets feasible. The first generation mobile phones as mentioned above were analogue where the voice frequencies were sent through the air which is a very inefficient use of the spectrum. Due to rapid growth thereafter, no standard was found in any country and each country developed its own system which was incompatible with other systems. The analogue system in the UK was TACS, in France it was RC-2000, in Germany it was Netz B, in Italy RMTS and in the rest of Europe it was NMT 450 (Sirel & Waverman, 2000). This created difficulties both for the carriers as well as the users who could not use it if they traveled. The GSM association is an international organization dedicated to providing, developing and overseeing the worldwide wireless standard of GSM. CDMA designed in the United States has been the dominant technology used in North America and parts of Asia (Wisegeek, n.d.). While GSM networks continue to increase its user base in US, CDMA is making progress in other parts of the world. By the beginning of the 21st century, one billion cellular phones used this technology (ICFAI, 2003). Gradually GSM became a standard in Europe while in the US there are four systems – GSM, TDMA ( a digital competitor to GSM), D-AMPS (analogue) and CDMA. All four standards have reached almost full coverage in US. The European approach of having a well-defined standard is due to a truly compatible network of mobile networks, fast spread of the technology, higher penetration rates, economies of scale for manufactures and convenience for user (Sirel & Waverman). The pace of innovation in GSM was slow which resulted in diminished consumer choice. The difference between the two technologies lies in its coverage area, data transfer speed and other factors. GSM has always grown and adapted to the changing needs of the customer. GSM is continuously evolving at a rapid pace and provides several voice and data enabled services. Just as GSM was being standardized, better solution in mobile technology was found in CDMA which is also digital wireless technology. In CDMA there is no division of the frequency band as the same frequency band is used repeatedly (ICFAI, 2003). Due to this it is also called Spread spectrum. CDMA was commercially introduced in 1995 and by 2003 it was the fastest evolving technologies. CDMA provides clear, reliable voice communication and good data services. In 1999 CDMA was selected as the industry standard for 3rd generation (3G) wireless systems. The radio frequency can normally be shared by different users accessing the same frequency band without causing interference (Naavi, 2004). The techniques used for this are TDMA (Time division multiple access), FDMA (Frequency division multiple access) and CDMA (Code division multiple access). GSM is a form of multiplexing and uses a combination of TDMA and FDMA. It divides the available bandwidth among different channels. GSM can allow eight simultaneous calls on the same radio frequency. CDMA too optimizes the use of the available bandwidth and allows the use of a particular frequency for a number of signals. In CDMA technology every channel uses the full available spectrum. Individual conversations are encoded with a pseudo-random digital sequence. CDMA was first used during the World War II by the English allies to foil German attempts to jam transmissions. To make it difficult for Germans to pick up the complete signal, the allies transmitted over several frequencies instead of one. Bandwidth is the major problem in modern times and CDMA is likely to replace GAM altogether. The number of users permissible in CDMA is higher than in GSM. The cost of setting up a CDMA network is less than setting up the GSM network. These days cellular phones serve more than just mobile phones. They serve double or triple duties as streaming video devices, podcast receivers and email devices. Hence speed in such cases become important than those who use the instrument just to make phone calls. CDMA is traditionally faster than GSM although both claim to be using the 3G technology. While both carriers have concentrated coverage in major cities, GSM carriers have roaming contract with other GSM carriers. This allows a wider coverage of more rural areas without the customer being levied roaming charges. CDMA is not able to cover as much rural areas like the GSM and they often have to contract with GSM in rural areas, in which case the charges are recovered from the users. As far as international roaming is concerned, GSM networks dominate the world. GSM cell phones can even be used overseas. Alternatively, one can even buy a SIM card in the host country and within minutes, with the local number of that country, one can call back home without paying any international roaming charges. This is not possible in CDMA-enabled phones as they are not card-enabled although now there are several countries that are CDMA enabled. Since the pace of innovation was slow in GSM, it could not provide the 2 megabytes per second bandwidth required for 3G mobility services. For 3G migration a more efficient technology is required and that is CDMA. 3G can provide up to 2 megabytes per second of wireless service to handheld sets which is in contrast to the existing 2G GSM technology that permits only a very low speed of 9600 bytes/second (Sirel & Waverman). With advances it can go up to 120Kbits per second but for internet access and higher bandwidth applications, GSM is facing limitations on speed and spectrum availability. 3G mobile phones use a different form of radio interface – CDMA which offers a speed three to four times higher than GSM. Besides, the 3G mobiles can be used on the existing 2G mobile phones network as well. With this advancement in technology, CDMA has become a threat to the European manufacturers. 2G CDMA is not approved for use in Europe. In the year 1999, Finland was the first country to issue 3G licenses which led to a fight over the technology and the standard for 3G networks. In 2000, the UK government used an auction to select among 13 bidders for five new 3G mobile licenses and those selected would have to invest huge amounts in order to deliver high-speed services to mobile phones and other devices. It had appeared that CDMA might fade into oblivion after losing the 2G battle to GSM but it has made a remarkable come back with 3G (Smackall, 2006). The CDMA’s long-term viability is still under suspicion as GSM is also aggressively moving into 3G. CDMA has a share of 13 percent of the cell phone market compared with 16 percent in 2004. Wireless Intelligence, a research group based in London, has forecast that nearly 500 million people will use CDMA technology by 2010, up from 350 million. Those using the GSM technology by 2010 are expected to be 3.5 billion up from 2.1 billion in 2006. It also forecasts that WCDMA (the GSM 3G technology) will pass CDMA2000 sometime in 2009 as the most widely used 3G technology. A research by a market research firm concludes that only one in ten mobile phones sold worldwide this year would be a 3G model. In Japan the users of 3G models are over 60% while Malaysia too has issued the 3G license. In Sweden the sale of 3G handset shave more than doubled in 2006 over the previous year. This represents 42% of the total handset market. As far as radiation is concerned, CDMA technology is most harmless. It does transmit microwaves while on standby mode like other technologies but it checks 800 times per second its transmission level. Therefore the radiation level is ten times less than GSM (Naavi, 2004). Another important point of differentiation is that CDMA system transmits signals only when the user starts conversation which means the listener is not affected by the microwave as the speaker does. There is a greater level of privacy and security of communication through CDMA technology. It appears that CDMA would be the dominating technology of the future. References: Belis, M (2006), The Invention of Radio, 12 Oct 2007 Goldsmith, A., (2005), Wireless Communications, 12 Oct 2007 JPL (1995), The pre-electromagnetic past, 12 Oct 2007 ICFAI (2003), GSM Vs CDMA - A Comparative Study, 12 Oct 2007 Naavi (2004), Mobile Forensics..Understanding the Technology of GSM Vs CDMA, 12 Oct 2007 Sirel, E., & Waverman, L., (2000), 3G Mobile: the push to wireless data across Europe, Business Strategy Review, 2000, Vol. 11 Issue 2, pp. 67-71 Smackall, (2006), GSM vs CDMA, The 3G Effect, 12 Oct 2007 White, T. H (2003), United States Early Radio History, 12 Oct 2007 Wisegeek (n.d.), What is the Difference Between GSM and CDMA? 12 Oct 2007 Read More