Wireless communication Essay Example

Wireless communication Essay A type of wireless communication that is most familiar to mobile phones users. Its called cellular because the system uses many base stations to divide a service area into multiple cells. Cellular calls are transferred from base station to base station as a user travels from cell to cell. (Bellis) History * First concept introduced in 1947 * Incorporated technology from car phones * Purely theoretical and no technology existed to support * Dr.Martin Cooper, a Researcher for Motorola is credited with inventing the first cellular phone * The First Cell Phone The first cell phone was named the DynaTAC8000X. It was created by Martin Cooper in 1984. It took over a decade to develop and $100 million. There were only about 2,000of these cell phones available to the public. * Weight- 2 pounds could store only 30 phone numbers. Battery needed to be charged for 10 hours. Talk time- 1 hour! The phone cost $3,995!! Uses * Text messaging Entertainment Uses: Games, music (mp3 player), books (e-boo k), and digital television broadcast * Social Uses: phone  call, text message, wireless internet (access to e-mail, social networking websites) * Organization Uses: calendar, finance manager, address book, storage for data * Hospital Uses: Used to view image (x-ray, MRI, etc). Means  of communication between nurses and clinicians. * Museum Uses: audio guide is provided through cell phones. * Educational uses: mobile learning provides access to lectures and test preps. * Track the culprits, location of a person   Cell Phones revolutionized long distance calling, making it much more inexpensive for long distance communication. * Cell phone logs have also been helpful in court cases where they can be used as evidence. * Smart Phones arent only used for communication, but for organizing schedules, jotting down notes, playing music, games, checking the weather, and other applications How do mobile phones work? Mobile phones and their base stations transmit and receive signals using electromagnetic waves (also referred to as electromagnetic radiation or fields, or radio waves).Electromagnetic radiation is emitted by many natural and man-made sources and plays a very important part in our lives. All electromagnetic radiation consists of oscillating electric and magnetic fields and the frequency, for ? (nu), which is the number of times per second at which the waves oscillate, determines their properties and the use that can be made of them. Frequencies are measured in hertz or Hz, where 1 Hz is one oscillation per second,1 kHz or kilohertz is a thousand Hz, 1 MHz or megahertz is a million Hz, and 1 GHz or gigahertz is a thousand million Hz or 109 Hz.Frequencies between about 30 kHz and 300 GHz are widely used for telecommunication, including broadcast radio and television, and comprise the radiofrequency (RF) band. Cellular mobile phone services operate within the frequency ranges 872–960 MHz and 1710–1875 MHz. An RF wave used for radio communicat ion is referred to as a carrier wave. The information it carries – speech, computer data, etc – has to be added to the carrier wave in some way, a process known as modulation. The information can be transmitted in either analog/ Digital form. Mobile Net workA mobile phone sends and receives information (voice messages, fax, computer data, etc) by Radio communication. Radiofrequency signals are transmitted from the phone to the nearest base station and incoming signals are sent from the base station to the phone at a slightly different frequency. Once the signal reaches a base station it can be transmitted to the main telephone network, either by telephone cables or by higher frequency (such as 13, 23 or 38 GHz) radio links between an antenna (eg dish) at the base station and another at a terminal connected to the main telephone network.These microwave radio links operate at rather low power and with narrow beams in a direct line of sight between the antennas, so that a ny stray radiation from them is of much lower intensity than the lower frequency radiation transmitted to the phones. Radiation Pattern of a Cell tower Signals to and from mobile phones are usually confined to distances somewhat beyond the line of sight.They can reach into buildings and around corners due to various processes including reflection and diffraction, that allows the radiation to bend round corners to some degree, but the coverage area from a base station is partly governed by its distance to the antenna’s horizon. An ideal network may be envisaged as consisting of a mesh of hexagonal cells, each with a base station at its centre but in practice the coverage of each cell will usually depart appreciably from this because of the topography of the ground and the availability of sites for the base stations.The sizes of the cells are usually less than the 35 km maximum because obstruction by hills, buildings and other ground features reduces the effective range. Freque ncies are reused several cells away and the capacity of a network (the number of simultaneous phone calls which may be made) depends on the extent of the frequency spectrum available, the cell diameter and the ability of the system to work against a background of interference from other cells.To accommodate the steadily increasing volume of users, cell sizes have to be progressively reduced (for example, by using base station antennas of lower height and reduced power) so that the frequencies may be reused more often. Indeed in large cities, base stations may only be a few hundred metres apart. Power output of the base stations are naturally more powerful and continuous in nature and they are received at close quarters for a longer period of time. People are not supposed to reside within 100 meters from the base stations in urban areas and within 300 meters in rural areas.Measure of RF Density: A SAR value is a measure of the maximum energy absorbed by a unit of mass of exposed tiss ue of a person using a mobile phone, over a given time or more simply the power absorbed per unit mass. SAR values are usually expressed in units of watts per kilogram (W/kg) in either 1g or 10g of tissue CDMA mobiles like those of Reliance and Tata Indicom have 1 Watts output; The GSMA mobile like BSNL, Idea and Airtel have 2 Watts and the US Analogue mobiles have a power output of approximately 3. watts. The SAR rating of each individual phone model is now being displayed on all mobile phone packaging in both the US and the UK, which will enable users to make informed choices when purchasing a handset. SarValues. Com brings this important information free of charge to all cellular users and also provides useful links to other Websites containing information. Whatever the outcome of the mobile phone debate, it makes sense to use prudent measures to reduce your radiation exposure, if possible.An obvious way to accomplish this, is by choosing a phone with a lower Sar Value. The point is to show that SAR Is not a property of a device itself, but a combination of a device and the way it is used. Mobile phones are now a large part of our every day life, they are probably the most useful gadget ever invented! The thing is though, every now and again research comes forward suggesting that mobile phones should be used responsibly, as the evidences are fast coming up to be displayed having its impace in Human health, environment and society.Biological Effects : Many scientific studies have investigated possible health symptoms of mobile phone radiation. These studies are occasionally reviewed by some scientific committees to assess overall risks. A 2007 assessment published by the European CommissionScientific Committee on Emerging and Newly Identified Health Risks (SCENIHR ) concludes that the three lines of evidence, viz. animal, in vitro, and epidemiological studies, indicate that exposure to RF fields is unlikely to lead to an increase in cancer in humans. Thermal effects :One well-understood effect of microwave radiation is dielectric heating, in which any dielectric material (such as living tissue) is heated by rotations of polar molecules induced by the electromagnetic field. In the case of a person using a cell phone, most of the heating effect will occur at the surface of the head, causing its temperature to increase by a fraction of a degree. In this case, the level of temperature increase is an order of magnitude less than that obtained during the exposure of the head to direct sunlight. The brains blood circulation is capable of disposing of excess heat by increasing local blood flow.However, the cornea of the eye does not have this temperature regulation mechanism and exposure of 2–3 hours duration has been reported to produce cataracts in rabbits eyes at SAR values from 100-140W/kg, which produced lenticular temperatures of 41 °C. There were no cataracts detected in the eyes of monkeys exposed under similar conditions. Pre mature cataracts have not been linked with cell phone use, possibly because of the lower power output of mobile phones. Non-thermal effect: The communications protocols used by mobile phones often result in low-frequency pulsing of the carrier signal.Whether these modulations have biological significance has been subject to debate. Some researchers have argued that so-called non-thermal effects could be reinterpreted as a normal cellular response to an increase in temperature. The German biophysicist Roland Glaser, for example, has argued that there are several thermoreceptor molecules in cells, and that they activate a cascade of second and third messenger systems, gene expression mechanisms and production of heat shock proteins in order to defend the cell against metabolic cell stress caused by heat.The increases in temperature that cause these changes are too small to be detected by studies such as REFLEX, which base their whole argument on the apparent stability of thermal equil ibrium in their cell cultures. Other researchers believe the stress proteins are unrelated to thermal effects, since they occur for both extremely low frequencies (ELF) and radio frequencies (RF), which have very different energy levels.Another preliminary study published in 2011 by The Journal of the American Medical Association conducted using fluorodeoxyglucose injections and positron emission tomography concluded that exposure to radiofrequency signal waves within parts of the brain closest to the cell phone antenna resulted in increased levels of glucosemetabolism, but the clinical significance of this finding is unknown. Blood–brain barrier effects: Swedish researchers from Lund University (Salford, Brun, Persson, Eberhardt, and Malmgren) have studied the effects of microwave radiation on the rat rain. They found a leakage of albumin into the brain via a permeated blood–brain barrier. This confirms earlier work on the blood–brain barrier by Allan Frey, Osc ar and Hawkins, and Albert and Kerns. Other groups have not confirmed these findings in in vitro cell studies or whole animal studies, however Frey alleges that an editor determined that a researcher who claimed that his attempts to replicate Freys research had not validated Freys results had incorrectly interpreted his own results, and that his research had confirmed Freys results.Cancer: The International Journal of Epidemiology published a combined data analysis from a multi national population-based case-control study of glioma and meningioma, the most common types of brain tumour. The authors reported that the wall of capillaryblood vessels situated in the brain are very thin made up of single layer of endothelial cells. Microwaves trigger changes to protein structures in endothelial cells,allowing toxins to enter the brain and making them tumorous. Mobile phones can affect pacemakersUnder certain circumstances, mobile phones can have adverse effects on the function of pacemake rs, but the devices usually start working properly again once the phones are moved away, researchers in Turkey report. The most essential recommendation to patients according to thereport is that mobile phones must be kept at least 20 cm away from pacemakers. For this purpose, it is sufficient for patients not to use the ear on the side of the pacemaker while talking on the mobile phone and not to carry the mobile phone in the shirt pocket on the side of the pacemaker.Infertility Problems : Using a hands-free device with a cell phone may affect fertility if phone is kept close to the testicles, Cleveland Clinic researchers warn in the journal Fertility and Sterility. Men who use these hands-free devices tend to carry their cell phones in their pants pocket or clipped to their belts at the waist while in talk mode have impact on semen quality. As a result, they may be exposing their testicles to damaging radiofrequency electromagnetic waves, explains Ashok Agarwal, PhD, head of the a ndrology laboratory and the irector of the Center for Reproductive Medicine at the Glickman Urologoical and Kidney Institute at the Cleveland Clinic in Ohio. Cell Phones Effect on environment: We are living in an environment filled with artificial radiations. The electromagnetic radiation playing role in the decline of animal and insect population. The EMR is so powerful that it affects the biological systems of birds, insects, even humans. In September 2010, the ministry established a ten member committee under Bombay Natural History Society (BNHS) with director Asad Rahmani to study the impact of cell phone towers on birds and bees.This group of experts reviewed 919 studies performed in India and abroad. Of the 919 studies, 593 showed the negative impact of mobile towers on birds, bees, humans, wildlife and plants. Effect on farm animals * Dairy cows- Decreased milk production, spontaneous abortions, reproductive and developmental problems, and general decline in overall health. * Sheep dogs, cats, rabbits living near base stations affected. Cell phones and Birds * Sparrows have disappeared completely from the cities at least four years ago in Britain as mobile phones grew in popularity. 3G mobiles were introduced in 2003; there are 65 million users in UK by 2005. In a research by Spain conservation biologist Alfonso Balmori there is difference in how the birds behaved close to the phone antennae. * Young birds die from unknown causes. Bird couples frequently fought, while constructing their nests stick fell to the ground. * Some nests were never completed and the storks remained passively in front of antennae. * Laboratory studies show bird embryo die when exposed to microwaves. Effect on Biodiversity * Electromagnetic radiations of mobile phones are directly related with the disturbance in ecosystem and ultimately biodiversity. 230 species (several million birds) die each year from collisions with telecommunications in the United States during migration. * Birds have thin skulls. Accidents happen mainly in night, in fog, bad weather when birds might be using the earth’s magnetic field for navigation. Effect on chicks According to a study 75% chick embryos died due to exposure to cell phone Effect on rabbits 2 to 3 hours exposure of rabbits to electromagnetic radiations showed cataracts because cornea doesn’t have thermal regulation. Bacteria and cell phones:The problem with phones is that we are in constant contact with them, and we spend a lot of time in close proximity to our faces and mouths and because it’s an electronic device, most people are hesitant about cleaning them. The cell phone has 10 times more germy than a toilet seat. Infectious microbes on the surface of a Smartphone including staphylococcus have an excellent chance of making their way to your eyes, nose and mouth Effect on Honey bees: Scientists may have found the cause of the worlds sudden dwindling population of bees and cell phones may be to blame.Research conducted in Lausanne, Switzerland has shown that the signal from cell phones not only confuses bees, but also may lead to their death. Over 83 experiments have yielded the same results. With virtually most of the population of the United States (and the rest of the world) owning cell phones, the impact has been greatly noticeable. Led by researcher Daniel Favre, the alarming study found that bees reacted significantly to cell phones that were placed near or in hives in call-making mode. The bees sensed the signals transmitted when the phones rang, and emitted heavy buzzing noise during the calls.The calls act as an instinctive warning to leave the hive, but the frequency confuses the bees, causing them to fly erratically. The study found that the bees buzzing noise increases ten times when a cell phone is ringing or making a call aka when signals are being transmitted, but remained normal when not in use. The signals cause the bees to become lost and disoriented . The impact has already been felt the world over, as the population of bees in the U. S. and the U. K. has decreased by almost half in the last thirty years which coincides with the popularization and acceptance of cell phones as a personal device.Studies as far back as 2008 have found that bees are repelled by cell phone signals. Bees are an integral and necessary part of our agricultural and ecological systems, producing honey, and more importantly pollinating our crops. As it is unlikely that the world will learn to forgo the convenience of cell phones, it is unclear how much they will contribute to the decline of bees, and their impact on the environment. Effects of cell phones on society The effects of cell phones on society will always be a double edged sword. The debate is never ending.Both sides have compelling arguments. But although there are some disadvantages, when looking around, one of the first sights I see are people walking with one hand up to their ear, like an e vidence that cell phones have become important in our daily life. One effect of cell phones on society is availability to keep in touch with family, friends or business partners almost in every place and every time. You do not have to wait until evening, when you will be at home, or find a telephone boxes to call some friend or family member, if you have to tell them something important.Moreover – cell phones are the perfect way to stay connected with others in the event of emergency. They provide us with a sense of security. In the event of emergency or loss cell phone can allow others to connect with you quickly and could possibly save your life. If you feel insecure or something has happened to you or to a person next to you, you can call to get help. For instance, most of Americans (about 74%) who use cell phones say they have used their mobile device in a critical situation and gained valuable help. Besides that today cell phones are more and more easily to use.They are capable of not only receiving and making phone calls, but taking, sending and receiving photos, sending data, you can use the Internet to check your e-mail, a calendar to plan your time, an alarm clock or a calculator. In short – nowadays cell phones are useful in different daily situations. But all opinions could never be the same. Some people believe that cell phones influence us negative. They say – health problems are one of the results of owing a cell phone. That is because of the negative radiation, what they have, when the phone is in your pocket or next to you.However scientists still have not proved the badness of.. Recommendations: The International Commission for Non-ionizing Radiation Protection is the authority for monitoring Ionizing radiation of mobile phones and Base Stations. This body has spelled out definite guidelines for the radiation levels allowed and the base station lists are classified accordingly Now let us see the recommendations for safe us e of mobiles: Various steps to be followed to decrease the burden of Radiation Effect: * Step1 Minimize the duration of use, since certain effects of electrmagnetic radiation (e. . thermal effects on brain) are accumulative. One should not talk for more than three minutes at a stretch and should take at least 15 minutes break in between calls. * Step2. Use hands-free to decrease the radiation to the head. Accidents caused by inattension are still there in this situation. * Step 3. Keep the cell phone away from the body. Use a speaker phone or the head set. * Step 4. Limit the use of cell phone by children. * Step 5. Avoid living near the base stations * Step 6. Avoid phone usage while crossing the street. * Step 7.Never use a cell phone when a conventional phone is available. * Step 8. Mobile phones should be prohibited near Intensive Care Units and Operation theatres. * Step 9. The practice of installing antennas needs to be regulated. * Step 10. The specific absorption rate (SAR) value for each hand set should be provided by the manufacturers on the website as well as in the user’s manual, as per the International Commission on Non-Ionizing Radiation Protection guidelines. * Please take this into consideration and use caution on your phones. * You tell everyone on the road and off the phone.Future Perspectives: As the present day world is more dependent on Mobile phone in their day to day life ,there is need for researcher to discover mobile phones that emit less radiation. RADISAFE  , is one such invention. It is an anti radiation mobile chip reduces over  99. 95%  of radiation emitted from your mobile phone, and makes your mobile phone totally harmless as certified by the worlds premier electronics testing laboratory,  california institute of electronics and materials sciences, USA. But for its application in the market , there is a long way to go.