Review And History Of CDMA Computer Science Essay

Review And History Of CDMA Computer Science Essay CDMA technology was used many times ago at the time of world war-II by the English soldiers to stop German attempts at jamming transmissions. English soldiers decided to transmit signals over several frequencies, instead of one, making it difficult for the Germans to pick up the complete signal. CDMA has been used in many military applications, such as anti-jamming (because of the spread signal, it is difficult to jam or interfere with a CDMA signal), ranging (measuring the distance of the transmission to know when it will be received), and secure communications (the spread spectrum signal is very hard to detect). In 1949, Claude Shannon and Robert Pierce develop basic ideas of CDMA. In March 1992, the TIA (Telecommunications Industry Association) established the TR-45.5 subcommittee to develop a spread spectrum digital cellular standard. In July of 1993, the TIA gave its approval for the CDMA Technology standard. In September 1998, there were 16 million subscribers on CDMA systems worldwide. Now, 22 countries support CDMA. Verizon, used to be the largest carrier, is now second behind ATT, is using CDMA. Other Famous companies using CDMA are Sprint, Alltel in abroad, Tata indicom and Reliance InfoComm in India. 2. What is CDMA? Generally a fixed amount of frequency spectrum is allocated to a cellular system by the national regulator (e.g. in the United States, the Federal communication commission). Multiple-access techniques are then deployed so that many users can share the available spectrum in an efficient manner. Multiple access systems specify how signals from different sources can be combined efficiently for transmission over a given radio frequency band and then separated at the destination without mutual interference. The three basic multiple access methods currently in use in cellular systems are: A. Frequency division multiple access (FDMA) B. Time division multiple access (TDMA) C. Code division multiple access (CDMA) A. Frequency division multiple access (FDMA) The available bandwidth is splits into non-overlapping frequencies and these disjoint sub bands are dedicated to the different users on a continuous time basis. Channel bands behave as buffer zones to minimize interference between different users. B. Time division multiple access (TDMA) Each user has given the full spectral occupancy to the channel, but only for less time interval. Buffers zones are used as guard times inserted between the assigned time slots. This is done to decrease interference between users by permitting for time uncertainty that arises due to system inadequacies. C. Code division multiple access (CDMA) The main Drawback of FDMA and TDMA is that only one subscriber at a time is assigned to a channel. No other conversation can access this channel until the subscriber s call is finished or until that original call is handed off to a different channel by the system. The above drawback is overcome in this third technique. CDMA systems utilize the spread spectrum technique, whereby a spreading code (called a pseudo-random noise or PN code) is used to allow multiple users to share a block of frequency spectrum. Detailed Description of How CDMA work is explained below. 3. How CDMA works? With CDMA, unique digital codes, rather than separate radio frequencies or channels, are used to distinguish subscribers. The codes are used by both the mobile company and the base station, that codes are called pseudo-Random Code Sequences. CDMA is a spread spectrum technology, which means that it spreads the information contained in a particular signal of interest over a much greater bandwidth than the original signal. CDMA uses Direct Sequence Spread Spectrum (DSSS) technology. In DSSS technology, Signal is transmitted by adding random data-bits called chip. This addition is done by the direct sequence transmitters. Now signal contains both, a useful signal and a signal that appears to be interference (the chips) is transmitted. The receiver easily identifies the chips and subtracts them, leaving only the useful signal. This means that original signal is spread over several frequencies simultaneously. This can deliver secure communication such that the transmitted signal can not be detected or recognized easily by unwanted listeners. It can discard interference whether it is the unintentional interference by another user simultaneously trying to transmit through the channel, or the intentional interference trying to j am the transmission. In TDMA, the original call is transmitted at 9600 bps (9.6 kbps) but when put on the CDMA, the call is spread over a 1.23 Mbps bandwidth, so it can be transmitted at a higher speed. Unique codes are applied to the data bits that make up the telephone call for a particular user. The cellular telephone receiving the call takes off the data codes and the call is converted back to its original 9600 bps. The use of these data codes enables CDMA systems to differentiate data bits from many different calls in the cell. CDMA networks use a scheme called soft handoff, which minimizes signal breakup as a handset passes from one cell to another. The combination of digital and spread-spectrum modes supports several times as many signals per unit bandwidth as analog modes. CDMA is compatible with other cellular technologies, this allows for nationwide roaming. 4. Factors affecting CDMA functionality Although CDMA does not have some capacity limitation, no maximum number of calls per single, wide band-width channel is established. The number of calls that a channel can accommodate is based on 3 factors. A. Total bandwidth B. Geographical coverage C. Quality of sound ? The available bandwidth can be increased by decreasing the quality of sound or the area covered by network. ? Channels that primarily carry voice conversation do not use the extra capacity required to deliver CD-quality sound. So, more bandwidth is available to provide longer transmission distance or to accommodate more cellular calls. ? Suppose there are 2N users that only talk half of the time then they can be accommodated with the same average bandwidth as N users that talk all of the time. 5. Types of CDMA Some of the types of CDMA transmission are as under A. Composite CDMA/TDMA B. CDMA C. cdmaOne D. cdma2000 A. Composite CDMA/TDMA It is Wireless technology that uses both CDMA and TDMA. It is used for large-cell licensed band and small-cell unlicensed band applications. It uses CDMA between cells and TDMA within cells. B. CDMA CDMA is characterized by high capacity and small cell radius, employing spread-spectrum technology and a special coding scheme. C. cdmaOne cdmaOne is the first generation narrowband CDMA. It is also called IS-95. D. Cdma2000 This includes 1XRTT CDMA standard. That is designed to double current voice capacity and support always-on data transmission speeds 10 times faster than typically available today. 6. Advantages of CDMA A. Capacity: The capacity of CDMA currently is 8 to 10 times greater than AMPS which uses FDMA transmission (and predicted to be 20 to 40 times greater in future) and 4 to 5 times greater than GSM which uses TDMA transmission (with prediction of being up to 13 times greater). B. Best for in built system and micro-cell. As in CDMA transmission, we do not need SIM card it is best for in-built system and micro-cell. C. Improves the voice quality. CDMA systems use precise power control that is, the base station sends commands to every mobile phone currently involved in a call, turning down the power on the nearby ones, and increasing the power of those further away. The result is a nice; even noise level across the carrier, with lower overall power levels and no spiky interference. D. Improves the telephone traffic capacity. E. It also provides Call privacy. F. Easily planned and maintained in comparison with FDMA TDMA 7. Disadvantage of CDMA The only disadvantage of installing CDMA system is the cost of the base station with its complex communication equipments. A CDMA base station costs approximately $150,000, while a similar station for TDMA costs approximately $50,000. 8. Referenced Books A. Business Data Communication Fourth edition By Shelly Cashman Serwatka B. COMPUTER NETWORKS, 3rd Edition By Andrew S. Tanenbaum 9. Referenced websites A. www.scsite.com B. www.wikipedia.com C. www.wisegeek.com D. www.palowireless.com E. www.indiastudychannel.com

Conflict Resolution in Office Romance Essay

Conflict is inevitable. It is a normal way of life. How we as individuals perceive each other depends on our ability to effectively resolve problems and how we cope with managing change. Some of us are unable to adapt to change therefore, it is expected that conflict will occasionally occur. There are different types of conflict that occur in our daily lives as well as in the workplace. However, the topic I choose to discuss as part of this conflict resolution paper is office romance that causes conflict. As we all are aware office romance is very common today in our society. It is no secret that people often find love on the job. There is a level of comfort and closeness that we share with our subordinates that we sometimes tend to fall in love with them. Office romance is dependent on a number of factors. Office romance can have both positive and negative effects on the working environment as well as work performance. It can cause conflict in the workplace, especially if it is a supervisor-subordinate relationship. It can affect the productivity of employees and may lead to sexual harassment and other claims. It can make co-workers uncomfortable and it can be dangerous because it can lead to conflict within the organization. Accusations of favoritism may occur and it may hinder the work performance of the parties involved as well as the co-workers. After analyzing the office romance that took place within the organization and the impact on which it had on employees, the recommended course of action to resolve the actual conflict that will make a difference to the future performance of the organization is to educate the employees on the issue of office romance. Develop a policy that declares what managers expect when it comes to office romance. The parties that are involved give them options such as disclosing the relationship to their boss and deciding who will leave the job if it gets too tough to handle and the parties do not want to terminate the relationship. Explain to them the actions that management will take if they do not solve the issue themselves. Enforce the rules on sexual harassment and office romance. Although, management cannot prohibit office romance, there are steps that they can take to ensure that it does not become a problem in the workplace, thus hiring a consultant that will help solve the issue is a good idea.

The Definition of Popular Culture in Sociology

Popular culture (or pop culture) refers in general to the traditions and material culture of a particular society. In the modern West, pop culture refers to cultural products such as music, art, literature, fashion, dance, film, cyberculture, television, and radio that are consumed  by the majority of a societys population. Popular culture is those types of media that have mass accessibility and appeal. The term popular culture was coined in the mid-19th century, and it referred to the cultural traditions of the people, in contrast to the official culture of the state or governing classes. In broad use today, it is defined in qualitative terms—pop culture is often considered a more superficial or lesser type of artistic expression. The Rise of Popular Culture Scholars trace the origins of the  rise of popular culture to the creation of the middle class generated by the Industrial Revolution. People who were configured into working classes and moved into urban environments far from their traditional farming life began creating their own culture to share with their co-workers, as a part of separating from their parents and bosses. After the end of World War II, innovations in mass media led to significant cultural and social changes in the west. At the same time, capitalism, specifically the need to generate profits, took on the role of marketing: newly invented goods were being marketed to different classes. The meaning of popular culture then began to merge with that of mass culture, consumer culture, image culture,  media culture, and culture created by manufacturers for mass consumption. Different Definitions of Popular Culture In his wildly successful textbook Cultural Theory and Popular Culture (now in its 8th edition), British media specialist John Storey offers six different definitions of popular culture. Popular culture is simply culture that is widely favored or well-liked by many people: it has no negative connotations.Popular culture is whatever is left after youve identified what high culture is: in this definition, pop culture is considered inferior, and it functions as a marker of status and class.Pop culture can be defined as commercial objects that are produced for mass consumption by non-discriminating consumers. In this definition, popular culture is a tool used by the elites to suppress or take advantage of the masses.Popular culture is folk culture, something that arises from the people rather than imposed upon them: pop culture is authentic (created by the people) as opposed to commercial (thrust upon them by commercial enterprises).Pop culture is negotiated: partly imposed on by the dominant classes, and partly resisted or changed by the subordinate classes. Dominants can create culture but the subordinates decide what they keep or discard.The last definition of pop cul ture discussed by Storey is that in the postmodern world, in todays world, the distinction between authentic versus commercial is blurred. In pop culture today, users are free to embrace some manufactured content, alter it for their own use, or reject it entirely and create their own. Popular Culture: You Make the Meaning All six of Storeys definitions are still in use, but they seem to change depending on the context. Since the turn of the 21st century, mass media—the way pop culture is delivered—has changed so dramatically that scholars are finding it difficult to establish how they function. As recently as 20 years ago, mass media meant only print (newspapers and books), broadcast (televisions and radio), and cinema (movies and documentaries). Today, it embraces an enormous variety of social media and forms. To a large degree, popular culture is today something established by niche users. What is mass communication moving forward? Commercial products such as music are considered popular even when the audience is tiny, in comparison to such pop icons as Britney Spears and Michael Jackson. The presence of social media means consumers can speak directly to producers—and are producers themselves, turning the concept of pop culture on its head. So, in a sense, popular culture has gone back to its simplest meaning: It is what a lot of people like. Sources and Further Reading Fiske, John. Understanding Popular Culture, 2nd ed. London: Routledge, 2010.Gans, Herbert. Popular Culture and High Culture: An Analysis and Evaluation Of Taste. New York: Basic Books, 1999.McRobbie, Angela, ed. Postmodernism and Popular Culture. London: Routledge, 1994.Storey, John. Cultural Theory and Popular Culture, 8th ed. New York: Routledge, 2019.

Online Education - 1381 Words

Online Education Education is an important part of peoples lives; it will either make them or break them in the future depending on the careers they choose. Education is greatly diverse today in comparison to the 1950s because of advancements in teaching and other great inventions that provide easier techniques of teaching. One major issue that has been raised is distant learning courses and online education. Distant learning could be any format from VHS videos, DVDs, or internet courses online. Online education has been legal since 1993 and is a new way of teaching students of all ages. Online education has been gaining popularity through out the years because of the ease of the internet. The internet has made it easier for people to†¦show more content†¦For example, a child of a farmer can help the family out in the morning with the farming chores then go to an online class later on. Rural kids may also take additional educational classes online that their school does not provide. Children in the movie industry may also take online courses to keep up with their studies while on the road filming movies. Hillary Duff takes online course while she films. As the price of education continues to rise, the rate of students applying for online educational classes will continue to get greater. The price for a unit at Long Beach City College is $26 and the price per unit will continue to rise as long as there is a deficit in Californias budget. Online courses provide a cheaper alternative for schools that have a problem with their budget and actual classroom space. Teachers can also record themselves and the student can download the film if they miss the session. This gives a student the chance to catch up on a class session if he missed out on that day. In 2002, 12 of the 55 National Geographic Bees were homeschoolers meaning that courses than at home can provide a great teaching environment. Students do not have to put up with bad influences from regular schooling and help build their own identity without social pressures that traditional schooling may have. Some students may also earn their high school degree faster then their peers. While the pros are stated some cons areShow MoreRelatedOnline Education And Online Schools946 Words   |  4 Pagestypes of schools starting with online and public. How would someone know which one to choose? While some believe the quality of online education isn’t as good as a regular school’s, online school is just as effective or more and should be continued as a teaching resource because online students are getting higher test scores and more options are offered by online schools. One of the reasons why online school is more effective than regular school is by cause of online students have shown higher testingRead MoreOnline Discussion Of Online Education1303 Words   |  6 Pagesdiscussion of online education in philosophy, there would sometimes come a rather curious moment in the conversation. I began to think of it as the â€Å"microwave question moment.† Many years ago, when microwave ovens first were advertised, there was a rather clever ad depicting a salesperson standing in front of a crowd of people, going on and on about all the wonderful advantages of microwave cooking, until a deep voice from the back spoke up with: â€Å"But does it brown the food?† Online course deliveryRead MoreOnline Education Essay712 Words   |  3 PagesOnline Education Online learning is definitely one of the newest and fastest moving industries; more and more students are opting to getting their degree this way instead of going to a land college, mostly due to the convenience of the schedule, where before a full time employee, could not fit schooling into their schedule, but they are finding out now that they can do this through the online environment, so they are utilizing this alternative way of achieving their higher education. Yet, the onlineRead MoreBenefits Of Online Education1136 Words   |  5 PagesOnline classes have become a more popular source for learning in the education system over the past couple of years. In the technology based world lived in today this is no surprise, it seems that everything is turning from human performed to technology based. The technology based world lived in has good and bad consequences, with technology based classes the need for teachers in the classroom teaching the material is declining. Along with j obs declining, many argue online learning may not be providingRead MoreTraditional Education And Online Education926 Words   |  4 PagesBatter, Online or Traditional Education Imagine that someone studies and has a neighbor in the same age. They study in together until high school. Someone continues to go to university but his neighbor decides to stay at home. They finally graduate and discover that his neighbor also graduate. Here will be there a lot of the questions beginning revolve in his head. How does his neighbor graduate and not go to school? The answer is an easy. His neighbor benefited from technology in education. This isRead MoreOnline Learning And Online Education1115 Words   |  5 Pagesdefinitely been absorbed into the education world. When one mixes technology and education, online learning is brought to life. Many believe that going to school online is a fabulous invention, because online classrooms can bring education to anyone, in any place imaginable. Some also argue that online classes can be more affordable than taking classes in the traditional classroom. Although a large number of American students believe that online learning is a valuable education tool, numerous research studiesRead MoreOnline Education Vs. Education1303 Words   |  6 PagesA Current trend that is occurring within the field of education is online education. The purpose of an online education is to allow student to receive a degree without having to be present or on campus. Online education helps working adults pursue higher education and gives them better career opportunities. It will also help people increase their lifetime earnings, Online education also helps to connect with people we would have never dreamed of interacting with it also gives students opportunitiesRead MoreOnline Education Vs Traditional Education1068 Words   |  5 PagesOn-Line Education versus Traditional Education Introduction/Thesis Online education has rapidly become a popular alternative to traditional education, due to the flexible nature of the courses and also the fact that the online learning environment may not require additional expenses. However, some people find traditional learning to be more advantageous than online learning. The traditional learning environment provides some people with more support throughout their scholastic career. When lookingRead MoreBenefits Of Online Education901 Words   |  4 Pagesgetting education and degrees online. A few years ago online education was never thinkable, and yet it has become to reality and it is widely expanding with popularity. Online education is a type of educational instruction that delivers learning to individuals to their own homes, and it is getting very popular among nontraditional student and others. Individuals prefer online education because they find it comfortable and better at their own house. To further more, some advantages of online ed ucationRead More Online Education Essay1378 Words   |  6 Pages Online Education Education is an important part of people’s lives; it will either make them or break them in the future depending on the careers they choose. Education is greatly diverse today in comparison to the 1950s because of advancements in teaching and other great inventions that provide easier techniques of teaching. One major issue that has been raised is distant learning courses and online education.   Ã‚  Ã‚  Ã‚  Ã‚  Distant learning could be any format from VHS videos, DVDs, or internet courses