Transformation In Bless Me Ultima - 1980 Words

Bless Me, Ultima is a transformative novel truly represented by the series of events that Antonio experienced. Throughout the story, Antonio was forced to transform from a boy to a man after the severity of tensions of opposites in his life caused him to question everything he had ever known. Antonio reflected upon battles of opinions in his own household, religious differences, and stepping outside of his cultural upbringing for the first time. When Antonio witnessed an extreme amount of death, the sight of the golden carp, and the magical healing powers of Ultima he began to question his Catholic roots and potential participation in the priesthood. When God failed to respond to Antonio s consistent questioning, he was no longer†¦show more content†¦Never. It was frightening to think of missing mass on Sunday, then dying and for that one mortal sin to go to hell forever. (Anaya 199-200) This phrase specifically shows the complexity in which Antonio thinks about the commandments of religion at such a young age, especially in the aspect of questioning what is happ ening after death. Aside from the constant death, introducing Antonio to the golden carp is the primary reason behind his questioning of Catholicism and just gods in general. When Antonio sees the carp for the first time his world collides. We see this specifically when he says, Swear by the cross of the Church that you will never hurt or kill a carp. This statement alone combines both Catholicism and Paganism. He presents us with the verbiage of the cross in his Church, along with the golden carp that he physically saw and was told to never harm. At this point, he is struggling to understand how he is supposed to believe in a God he cannot see, when the golden carp is a visual form of a miracle, happening right in front of his very own eyes. We know that Antonio is beginning to question his faith and future as a priest when he says, If I had not seen the golden carp perhaps I would not have believed him. But I had seen too much today to doubt him. (Anaya 116) and I wondered if God was aliveShow MoreRe latedBless Me Ultima Loss of Innocence820 Words   |  4 Pagesto a big, grown adult? What problems do we face? Who helps us decide our future? In Bless Me Ultima by Rudolfo Anaya, Antonio Mà ¡rez must forward on the way to his own moral self-sufficiency. Antonio is put into the center of many distressing events which cause him to grow up faster, and lose his innocence. Antonio has many questions about spirits, god and beliefs. To get his answers, he must undergo a transformation. To attain maturity, you must have a loss of innocence. For example, when a kid findsRead MoreLiterary Criticism : The Free Encyclopedia 7351 Words   |  30 PagesKnowles (1959) To Kill a Mockingbird, by Harper Lee (1960)[30] Dune, by Frank Herbert (1965)[33] The Outsiders, by S. E. Hinton (1967)[34] A Wizard of Earthsea, by Ursula K. Le Guin (1968)[35] I Know Why the Caged Bird Sings, by Maya Angelou (1969) Bless Me, Ultima, by Rudolfo Anaya (1972) The World According to Garp, by John Irving (1978) The Discovery of Slowness, by Sten Nadolny (1983) Bright Lights, Big City, by Jay McInerney (1984)[36] Ender s Game, by Orson Scott Card (1985)[34] The Cider House Rules

Capital Punishment in Canada Essay - 2901 Words

Capital punishment is crimes most dreaded consequence, death. Hanging was Canadas form of capital punishment up until 1976 when it was abolished. Websters Dictionary defines capital punishments as: The penalty of death for the commission of a crime. (Websters, 1994, 43). The chance of capital punishment being reinstated in Canada has been very slim up until now. Recently the Canadian Alliance Party has put forth efforts to reinstate it, which has put the controversial topic back up for debate. This has divided many Canadians concerning their beliefs. Capital punishment should never be reinstated in Canada as it is a barbaric practice that is unjust. This essay will clearly demonstrate that reinstating capital punishment†¦show more content†¦In addition, capital punishment vetos section 12 of the Charter which protects everyone from cruel and unusual punishment. Capital punishment is unusual because it isnt exercised for many crimes in the criminal code, as it was on ly used for murders of police and prison guards. Capital punishment is also cruel. The United Nations believes Capital Punishment is a form of cruelty and inhumanity unworthy of a civilization which claims to be humane; doctors report that even the most efficient methods do not result in instantaneous and painless death. (UN-Department of Economic and Social Affairs, 1962, 61). Capital punishment is both cruel and unusual and thus violates section 12 of the Canadian Charter of Rights and Freedoms which states: Everyone has the right not to be subjected to cruel and unusual treatment or punishment. (Gibson and Murphy, 1990, 55). By taking the life of a criminal, the Bill of Rights would be unlawfully vetoed as well, and therefore the Bill would be useless if it has no validity. The Bill guarantees everyone the right to life from the moment they are born and at no circumstances can this right be taken away. If Canada were to reinstate capital punishment it would result in theShow MoreRelated Capital Punishment in Canada Essay854 Words   |  4 Pages Capital Punishment in Canada nbsp; As violence becomes an increasing concern among Canadians, people are calling for the reinstatement of capital punishment. This controversial issue has been ailing politicians and public morality since its abolition in 1976. As one examines the arguments for and against the reinstatement of capital punishment; examples of modern day cases dealing with capital punishment; and statistics on such cases, one can better appreciate the reasons why this barbaricRead MoreA Look on the Impact of Capital Punishment in Canada1240 Words   |  5 PagesCapital punishment was the most severe punishment within the Canadian Justice system before it was abolished in the 1970’s. It is still used in many other countries around the world such as the United States, China and India, as it is believed to lower the crime rate within their country. Capital punishment was basically a form of torturing the suspect, but to their death as a consequence of their heinous crime. Many believe that capit al punishment should be reinstated into Canada, while others areRead MoreShould Capital Punishment Stay Illegal in Canada?636 Words   |  2 Pagesone of the reasons why I think it should remain illegal in Canada. The sentence doesn’t deter crime, (citation needed) and in some cases it only exasperates the crime which it was supposed to deter. Also, in order to keep an inmate on death row it costs on average ninety thousand dollars more than keeping an inmate for a life sentence, in the United States (Baskey-East, S. 2014). California has approximately the same population of Canada, and it uses the death penalty (37 million and 35 million peopleRead MoreCapital Punishment Infringes Upon Human Rights and Should Not be Reinstated in Canada2570 Words   |  11 PagesIn today’s society, capital punishment is a particularly controversial issue. The death penalty known for its barbaric form of punishment began in 1892 lasting for 69 years before bill C-84 was passed by the House of Commons resulting in the removal of the death penalty. Although capital punishment has been abolished for 48 years, society still has mixed opinions on whether our country would benefit by reinstating capital punishment or if it would be better to respect individual rights and keep themRead MoreThe Canadian Justice System And Capital Punishment1713 Words   |  7 Pagessystem in its views on capital punishment. Two men, Arthur Lucas, and Ronald Turpin was to be executed in Canada for committing crimes. Both had been accused of committing murder, Lucas for killing an officer while fleeing a robbery and Turpin for murdering an undercover narcotics officer. Both were hanged back to back at midnight and buried side by side with no marking on their graves. Lucas and Turpin were the last to be executed under capital punishment and since then Canada has stopped this practiceRead MoreCompartive Legal Systems Canada vs Usa1691 Words   |  7 PagesComparative Legal Systems (Canada vs. USA) Thesis: Canadas criminal justice system, specifically laws dealing with punishment, is far superior to that of the United States Canada and the United States of America are two neighboring countries who besides the border share numerous other key aspects. Though similar in beliefs and culture the two countries are far from alike. Their legal structure particularly the penal system is one of most significant boundaries between Canada and the United States.Read MoreCapital Punishment Deters Murder, and Is Just Retribution1364 Words   |  6 PagesCapital Punishment Deters Murder, and Is Just Retribution Capital punishment, is the execution of criminals by the state, for committing crimes, regarded so heinous, that this is the only acceptable punishment. Capital punishment does not only lower the murder rate, but it s value as retribution alone is a good reason for handing out death sentences. Support for the death penalty in the U.S. has risen to an average of 80% according to an article written by Richard Worsnop, entitled DeathRead MoreThe Abolition Of The Death Penalty1552 Words   |  7 Pagespenalty is used as a form of punishment in the eastern hemisphere for many crimes, such as espionage, terrorism, and first-degree murder. China holds the record for the largest amount of executions; the number remains largely disputed as death penalties are considered â€Å"state secret.† In some Middle Eastern countries crimes such as rape, adultery and theft also carry a death sentence. Canada is no stranger to capital punishments either. The first recorded death penalty in Canada was in 1749, as a sailorRead MorePunishing Criminals by Death Will Deter Future Crimes...or Not?1216 Words   |  5 Pagesexample of Canada. How crime was not deterred by the imposition of death penalty as a tool used by the system of justice. The essay states some of the research that has been conducted with the intention of proving that capital punishment can deter crimes. This paper points out the effects and imposition of capital punishments on criminal activities. The paper finally makes a conclusion on the issue of capital punishment as deterrence. Introduction Many people assume that punishment by deathRead MoreCapital Punishment And Its Economic, Political, And Social Impact On The United States Of America1739 Words   |  7 PagesINTRODUCTION Capital punishment, also frequently referred to as the  death penalty, is a government certified practice where a person is put to death by the state as a form of punishment for a crime they have committed (Henderson, 25). Crimes that are found punishable by death are referred to as  capital crimes  or  capital offences, and commonly include offences such as murder, treason, war crimes, crimes against humanity and genocide (Henderson, 48-9). The term  capital  is derived from the  Latin term

The Sale to Procter Gamble Free Essays

On February 28th 2005, Gillette was sold to Procter and Gamble for $57 billion. Gillette is based in Boston and was founded in 1901. It sells products in over 200 countries in 31 manufacturing plants in 14 countries. We will write a custom essay sample on The Sale to Procter Gamble or any similar topic only for you Order Now It is one of the leading manufacturing firms left in Boston. Procter and Gamble is based in Cincinnati, established in 1837 by William Procter and James Gamble and was incorporated in 1905. To date it has sold more than 300 brands of products in more than 160 countries. Because of the competition in this industry, Procter and Gamble thought it was a good idea to buy out Gillette. They had already noticed that Walmart had the biggest percentage of Procter Gamble’s revenue (17%) and this would grow to 30% after the merger. Also, there would be a cost savings of $14 to $16 billion a year and a 1% increase in sales growth after the merger. Key Issues One of the key issues is that 6,000 employees of Gillette would be losing their jobs. Another key issue is that severance packages from these kinds of mergers have been seen to be too high. For example, when Manulife Financial Corporation merged with John Hancock Financial Services, the Chief Financial Officer from John Hancock, David D’Alessandro, received a package of $16.4 million. When Bank of America bought Fleet Boston Financial Group, Chad Gifford (CFO of Fleet Boston) got $16 million. Now, Gillette’s James Kilts is getting a severance package of $30 million and could earn $172 million in cash   and stock. In fact, $50 million of the compensation package was directly tied to the merger. A lot of academics did not agree with this arrangement because they believe it should be tied to the performance of the company and not to the merger. Another issue is that employees of Gillette were already complaining about unfair working conditions and retirees were going to have to pay more for healthcare after the merger. How to cite The Sale to Procter Gamble, Papers

Hospitality Students Perceptions of Sustainability- myassignmenthelp

Question: Discuss about theHospitality Students Perceptions of Sustainability. Answer: Introduction Hospitality industry is one of the largest industries in the world with a global contribution of $7.6 trillion (US) in 2016 having immense effect on social wellbeing being a key contributor to revenue and job generator (Statista, 2016). However owing to its nature, it proves to put a lot of pressure on the ecology. Sustainability is the idea which emphasizes that human activity ought to be mindful of its actions to ensure conservation of the ecological balance and natural resources. Deloitte underlined the importance of sustainability as, Rising populations and increasingly scarce resources will provide a challenging business environment in which sustainability will need to be embedded within all facets of the industry, rather than regarded as a standalone issue.(Deloitte, 2014, p. 41) This research aims to investigate the perception of students of hospitality and tourism, who constitute the future workers of the industry and in that context, the presence of potential gender based differences. The insight gained is expected to aid educators regarding how they should approach sustainability education to instil the concepts to the future generation, ensuring that the industry could be better equipped in operating by keeping in mind the idea of sustainability. Literature Review Eagle et al. (2015) reported on a longitudinal study targeting undergraduate business students understanding of sustainability in business and highlighted a tendency of subjects to remain oblivious to their own capacity for exacting change and potential impact they could have in tackling environmental and sustainability challenges and thus being unwilling to change lifestyles. Reid, Petocz Taylor (2009) addressed a very specific challenge that exists with regard to implementing a curriculum which tackles sustainability issues in business education courses. They revealed that while some students of business do have considerable depth of understanding regarding sustainability and its need, many were naive and unaware of the full extent of its implications. Some had a limited understanding of sustainability as merely the act of ensuring continuity. Although, they did find evidence of students who viewed sustainability practices as a moral responsibility towards coming generations. Focu sing on existing scope of sustainability education, Wiek et al. (2013), appraised the opportunities in international education on sustainability concluding that only one out of seventeen institutions fulfil them. They went on to present the challenges presented by The Global Classroom Experiment, a composite experimental curriculum designed to fulfil those criteria. The study revealed that challenges exist in levels of administration and faculty who need to develop skills to help guide students who need to be flexible enough in worldview to contribute as well to a successful program. Kagawa (2007), conducted a study investigating perceptions of university students on sustainable development in light of their life styles, examining the effect of gender and their courses being related to the environment. The study adopted a statistical approach to investigate the matter, concluding that gender difference in perception was statistically significant although the difference become insign ificant when grouping based on courses. The subject under study in this paper is the existing gap in knowledge of college students enrolled in hospitality and related courses to be specific, putting emphasis on tentative gender differences by studying how they understand sustainability and therefore how academics could approach sustainability education for these people to ensure a standard of education which integrates sustainability education with the coursework. Unlike Kagawa(2007), the paper uses a qualitative research design to approach the issue. Research Questions The objectives of the research deals with answering the following: How do these future workers view sustainability in context of the hospitality industry? Are there any difference in the perception about sustainability between the male and female subjects? Research Methods The research is based upon a qualitative approach. The data consist of answers to a set of ten open-ended questions by twelve subjects six of them male and rets female, who are pursuing college courses which are relevant to the hospitality and tourism business industry. The specific methodology used here follows the guidelines of grounded theory. The data corpus has been divided into two sets, one for male interviewees and the other for females. The questions addressed their views about sustainability, its role in the hospitality industry and their home country. Core theoretical concepts relevant to the research questions are thus developed based on the responses. Tentative links between those concepts are developed, followed by verification through re-analysis of the data in context of those concepts and links (Graue, 2015). This is achieved through coding strategy which included open coding, axial coding and selective coding (Birks Mills, 2015). Open Coding is the practice of identifying, categorizing and cataloguing concepts within the textual data which could lead to relevant theories within the context of the relevant topic under study (Glaser, 2016). Repetitive or synonymous words which could lead up to common themes are noted and documented. The identified distinct themes are then used for further investigation (Urquhart, 2016). Axial Coding is the practice of relating the identified categories or themes to one another with the aim of determining any tentative association or causal relationship from a generalized point of view (Zhang Wildemuth, 2016). Selective Coding is concerned with taking into consideration the identified relationships in the axial coding step and then trying to determine the core or principal category supporting some theory which addressed the research question (Smith, 2015). Findings and key themes The primary idea of sustainability was found to be attributed by the males using concepts such as continuation, recycling, maintain and environment. For example, participant #2, is quoted to be referring to sustainability as I think it means something that can be continued (International, 19, #2). Similarly, participant #7 said, Something that is permanent or that can be recycled (International, 22, # 7). Notice that such explanations are quite short and vague. It was observed that they lacked cohesiveness in their concepts about what kind of role and how sustainability could play in their industry. The following quotes depict the contrasting ideas that the males hold. Anything to maintain a sustainable profit. (International, 19, #2). Compared to his answer for what he understands as sustainability is, the participant is seemingly thinking around the lines of business and overlooking the environmental context of sustainability. Comparatively, participant #7, seems to at least have a more concrete idea of what sustainability is as viable sustainability practices as apparent from his answer, In industry, Solar-energy can be used as a major source of energy. Solar energy is sustainable energy. (International, 22, # 7). Participant 10 was found to identify the concept with maintaining business rather than ensuring environmental sustainability through business practices. Relating to sustainability and initiatives, he said, The ability to maintain certain levels for a long time. I think mainly it would be to build and maintain customer loyalty. (International, 25, # 10). Although participant #16 admitted to not having a very good idea about sustainability, he revealed to identify sustainability practices in the industry with green energy. The relevance of such practices according to him is stated as, otherwise greenhouse effect and global warming will get worse. (International, 24, #16). Therefore the focus although is correct from moral perspective, it is suggested that he might lack, the insight regarding the business aspect of sustainability practices in the industry. Participant #18 displayed detailed knowledge about sustainability concerns and also pointed out water and energy conservations as options of sustainability practice, however he again failed to aptly explain why he felt that sustainability is important to his industry save for being a socio-ecological ideal, saying just, Yes it is very important. The females responses were found to be more descriptive. The primary idea of sustainability was found to be attributed using concepts such as environment, long-term, protection, business and customer. Notable among the answers is the following quote, Yes. As people become more and more environmentally conscious, future businesses should consider it. Otherwise, people will remember it as a bad business and gradually stop using it. (International, 20, #22) Participant #22 therefore could successfully identify the appeal of sustainability practices to customers and given rising global awareness and concern, its value as a marketing strategy. Her summarization of sustainability, emphasizes it in light of how essential it is to balance ecological concerns with business operations and thus how environmental sustainability relates to economic sustainability of the firm as well. possibility to last and maintain without environmental damage. Sustainability must be considered for a firm to radian in existence for long. Changes in people's perceptions make it clear. (International, 20, #22) Participant #11 displays similar understanding, saying, If a business is doing something sustainably, it can get more good cmpetitive advantage than other business. (International, 23, #11) Participant #14, sums up sustainability as, coordinated development f economic, social, respurces and environmental protection (International, 24, #14). However when asked upon the specifics of sustainability practices that could be employed in the industry the female participants , the responses seemed to invoke answers which did not seem to be aligned with the ideas of sustainability they displayed to possess in their answers to related questions. Contrary to that, the female participants, were found to be unable to identify sustainability practices and associated sustainability initiatives in the hotel industry with meeting customer needs, diversifying, etc. Participant #14, answered, To improve the experience of customers, for example, in the food and beverage department, we can try the innovation of dishes, varieties and prices, which are more affordable. (International, 24, #14). Participant #13 said, regarding initiatives as, Diversify the business to meet customer needs (International, 25, #13). Again, Participant #11, said, it is a process that a hotel business keep doing something. For example, a hotel's remains unique from other hotels. (International, 23, #11) This statement when considered with her answer to sustainability, means that although she views sustainability in context of marketing advantage, she lacks insight regarding the ideals of ecological sustainability. None of the females could identify any of the existing sustainability initiatives in the hospitality, suggesting that even though they have concept of what sustainability entails, but lack insight about the operational aspects within the industry. Both the groups thus seem to be insufficiently educated regarding the matter but their gap in knowledge is focussed in differing areas. It is apparent that the male participants are more sensitive towards environmental sustainability and its implementation rather than the economic and social aspect of it. They also seem to have more coherent idea about sustainable practices. In contrast to the male counterparts, the female respondents seem to be more sensitive towards economic sustainability (Alhaddi, 2015). They seem to be more aware of how unsustainable practices could adversely affect business in the long run and the marketing benefits of sustainable practices. However they seem to lack awareness about practices which support sustainability. Conclusions The males were more likely to view sustainability as environmental and ecological imperative whereas the females emphasised that sustainability is a business imperative for the long run. The males seem to focus more towards sustainability initiatives which could be and ought to be employed such as recycling, water and food conservation, use of green energy. The females on the other hand, expressed a more theoretical understanding of the rationale behind sustainability than actual practical sustainability initiatives that are undertaken by governments and hotels. References Alhaddi, H. (2015). Triple bottom line and sustainability: a literature review.Business and Management Studies,1(2), 6-10. Birks, M., Mills, J. (2015).Grounded theory: A practical guide. Sage. Deloitte. (2014).Hospitality 2015: game changers or spectators(p. 41). Deloitte LPP. Eagle, L., Low, D., Case, P., Vandommele, L. (2015). Attitudes of undergraduate business students toward sustainability issues.International Journal of Sustainability in Higher Education,16(5), 650-668. Glaser, B. G. (2016). Open coding descriptions.Grounded Theory Review,15(2), 108-110. Graue, C. (2015). Qualitative data analysis.International Journal of Sales, Retailing Marketing,4(9), 5-14. Kagawa, F. (2007). Dissonance in students' perceptions of sustainable development and sustainability: Implications for curriculum change.International journal of sustainability in higher education,8(3), 317-338. Reid, A., Petocz, P., Taylor, P. (2009). Business students conceptions of sustainability.Sustainability,1(3), 662-673. Smith, J. A. (Ed.). (2015).Qualitative psychology: A practical guide to research methods. Sage. Statista. (2016).Topic: Global Tourism Industry.www.statista.com. Urquhart, C. (2016). Grounded Theory.The International Encyclopedia of Communication Theory and Philosophy. Wiek, A., Bernstein, M. J., Laubichler, M., Caniglia, G., Minteer, B., Lang, D. J. (2013). A global classroom for international sustainability education.Creative Education,4(4A), 19. Zhang, Y., Wildemuth, B. M. (2016). Qualitative analysis of content.Applications of social research methods to questions in information and library science,318

Fire Is My Element free essay sample

I found my passion Freshman year when I joined the football team. Football is the only team sport I play, and it has taught me some of the most valuable life lessons I have learned. To be a successful football player, one must dedicate his mind, body, and soul to the game, for his team. Through the thick and thin. From six a.m. Winter morning workouts through double days and into the season, as a player you need to show unconditional commitment. Determination drove me to commit. Aspiring to reach my goals and achieve my dreams. Fire is my element, my essence. From the very beginning of my Football career, I have been nothing short of relentless. I always took pride in the way I approached the game. Year round I trained religiously, with determination as my fuel. As I trained, I was able to keep myself motivated with my willpower and my desire to succeed. We will write a custom essay sample on Fire Is My Element or any similar topic specifically for you Do Not WasteYour Time HIRE WRITER Only 13.90 / page I could not let myself down. And while I had my sights set on my goals, I was invincible. Or so I thought. Halfway through my junior season, I separated my left shoulder in a game against our cross town rival school, Soquel. After all my efforts, my first varsity season was cut short. I was devastated. The doctors told me to give it four to six weeks of physical therapy and that I should be alright. They told me I’m young and my body should heal quickly. Winter break came and went, and I wasn’t getting better. I returned to the doctors and they concluded that it wasn’t going to heal and proposed a surgical fix. My doctor stressed that it was a simple procedure, and that the recovery would take six to eight weeks. I told the doctor to schedule an appointment for me as soon as possible. The procedure was scheduled for early February, but when that time came I fell incredibly ill and was forced to push that date to April. This was yet another disappointing setback in my athletic career. All this time had passed and I remained crippled and unable to train for my Senior season. When my big day came, I wasn’t the slightest bit nervous for the operation. I was excited that I was going to get fixed. I missed doing what I love, and I was determined to get healthy and back at it. On the day of my operation. People asked if I was scared, I was quick to come back with â€Å"No, not at all. It’s going to be the best day of my life.† In my head, the day marked a turning point in my life. The next chapter, the road to recovery. Little did I know just how difficult it was going to be. The week following my surgery was Spring Break. It was the longest, loneliest week of my life. Soon after I began rehabilitation, my first task was to regain my range of motion. After a few months, I regained most motion, but I was still in chronic pain. School ended for the Summer and football workouts had begun. I trained around my injury. I was going to get myself ready to play ball. Slowly, but surely I was going to make my comeback. When padded practices began, somehow my shoulder still wasn’t right. Practically everyday I was faced with the question â€Å"Are you going to be able to play this year?† followed by a â€Å"When?†. For the first time, I doubted myself. But still, I showed up to practice everyday and continued my commitment. Before I knew it, Summer had ended and the season was underway. I still wasn‘t healthy. For the first few games, I watched from the sideline with a gleam in my eye. It was mentally draining, knowing how hard I’d worked, knowing that I wanted it more than anyone. Yet I couldn’t have it. Not yet. Halfway through my Senior season I was playing again. I completed my rehab, got a few cortisone injections, a doctors clearance and boom! I was back on the field after over a year. I felt like a new man. Despite all the setbacks, and what people had told me, I had overcome all odds. It was the hardest thing I’ve ever had to go through. Looking back at my experience, It is obvious that I have matured a lot from it., and I have come to reason with what happened to me and why. My injury and the road to recovery was an emotional roller coaster. This journey helped me build emotional strength. I have learned that determination is my key to success. My flame now burns brighter than ever. I now feel that I am able to handle anything life can throw my way. All it takes is the determination to succeed and the will to try hard.

75 Synonyms for Hard

75 Synonyms for Hard 75 Synonyms for â€Å"Hard† 75 Synonyms for â€Å"Hard† By Mark Nichol It’s easy to write about how hard something is, because so many synonyms exist for that vague word and its more formal cousin difficult. Many of these terms are somewhat interchangeable (that’s why they call them synonyms), but even then, the senses are often slightly distinct; do a little more research on usage when you find a promising variation for that abstract (or is it abstruse?) phrasing you’re attempting to finesse. 1. Abstract: disassociation from a practical reference that would aid in comprehension 2. Abstruse: difficult because of technical considerations 3. Arduous: great physical exertion 4. Augean: unpleasantly, overwhelmingly hard (a classical reference to the Augean stables, cleaned by Hercules as one of his legendary twelve labors) 5. Backbreaking: tiring and often dispiriting physical effort 6. Bruising: physically wearing and damaging 7. Brutal: unpleasantly difficult 8. Burdensome: physically or emotionally difficult 9. Challenging: requiring special effort; may have a positive or a negative sense depending on context 10. Complex: difficult because of multiple interrelated factors 11. Complicated: see complex 12. Convoluted: see complex; with an additional connotation of twisting or intertwining 13. Cruel: marked by uncompromising difficulty that disregards the worker’s welfare 14. Daunting: inspiring a feeling of great difficulty 15. Demanding: suggestive of a great commitment of time and effort 16. Distressing: causing emotional anguish 17. Effortful: requiring effort 18. Elusive: difficult to comprehend, or evasive 19. Exacting: requiring meticulous attention to detail, or requiring relentless effort 20. Exhausting: difficult in terms of physical or mental exertion 21. Formidable: discouraging because of expected difficulty; also has a positive connotation of impressiveness 22. Frustrating: producing feelings of hopelessness or defeat 23. Grievous: causing pain or suffering 24. Grim: evidencing unyielding difficulty or severity; can also mean â€Å"grim,† â€Å"gloomy,† or â€Å"sinister† 25. Grueling (also spelled gruelling): requiring unrelenting or extreme effort 26. Hairy: difficult (informal) 27. Harsh: excessively difficult 28. Heavy: involving great effort 29. Herculean: suggestive of great difficulty 30. Inhuman: so difficult as to seem beyond human capability 31. Insoluble: seemingly too difficult to be solved or resolved 32. Intimidating: so difficult that the task or prospect inspires fear or hopelessness 33. Intricate: see complex 34. Involved: see convoluted 35. Knotty: see convoluted 36. Labored: requiring wearying physical or mental exertion 37. Laborious: see labored 38. Merciless: marked by effort that seems to be required with no regard for the welfare of the worker 39. Moiling: requiring much effort 40. Murderous: suggestive of risk of physical or mental harm (informal) 41. Onerous: see burdensome 42. Opaque: difficult because of a lack of clarity or communication 43. Oppressive: harshly difficult 44. Overwhelming: too hard to do or bear without suffering 45. Painful: causing physical or mental discomfort or harm 46. Pick-and-shovel: suggestive of great manual effort 47-48. Problematic/problematical: difficulty in solving a problem 49. Punishing: difficulty heedless of consequences of physical or mental strain 50. Recondite: difficult to comprehend because of obscurity or the need to possess more knowledge 51. Rigid: inflexibly difficult 52. Rigorous: difficulty caused by conditions of inflexibility or requirements of great precision 53. Rugged: suggestive of conditions requiring strength and stamina 54. Serious: requiring a great deal of effort 55. Severe: difficult because of the nature of requirements or constraints or because of the need to expend great effort 56. Spiny: replete with difficulties 57. Sisyphean: suggestive of relentless, repetitive toil (a classical reference to Sisyphus, tormented in Hades by having to repeatedly roll a boulder up a hill, then retrieve it when it rolls down again) 58. Stiff: see rigid 59. Strenuous: see arduous 60. Stressful: so difficult as to cause tension or nervousness 61. Strict: difficult especially because of standards imposed 62. Stringent: see strict 63. Stubborn: persistently difficult 64. Sweaty: suggestive of great physical exertion, causing perspiration 65. Tall: see formidable (informal) 66. Taxing: see burdensome 67. Testing: calling for great effort, as if to test one’s abilities 68. Thorny: see spiny 69. Ticklish: difficult because of the problem’s sensitive nature 70. Tight: hard because of a lack of flexibility 71. Toilsome: see labored 72. Tough: physically or mentally demanding (informal) 73. Tricky: see ticklish 74. Trying: requiring great endurance 75. Uphill: see labored Want to improve your English in five minutes a day? 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Ethical Viewpoints Essay Example | Topics and Well Written Essays - 500 words

Ethical Viewpoints - Essay Example This deprivation imposes the same difficulty faced by children raised by a single parent. True marriage provides normal conditions of a normal atmosphere beneficial for the upbringing of children Most arguments additionally stipulate that, same sex marriage just serves to validate and promote the homosexual lifestyle. Gradually, these arguments have profoundly been modifying everyone’s perception and evaluations of behavior. Eventually, the legal system will completely embrace this type of abominable marriage and thus shadow certain basic moral values and cripple public morality. Morally this union is wrong and legal recognition will simply change this moral wrong to a civil right. Eventually, anti-gay activists state that legalizing same sex marriage will force the whole society to accept and the state will have to form laws that punish people especially state employees that express disapproval. This is because marriage affects the whole of society and this new pigment will compel others to betray their consciences. People attracted with the same sex have gradually been coming out of their closet actively demanding that they have the right to legally get married in same sex unions. Today’s generation is very liberal and they are not afraid to express what they feel. Some of the arguments echo the fact that everyone should be given the chance to form a lifelong bond with the partner they choose. They argue that it is their civil right to be recognized just like the same recognition was given to heterosexual relationships so should it be given to homosexuals. The law is for all and thus should not create a gap between people in a second class who will have lesser rights than others. This will be discriminating and thus not right. Arguments reiterate that Homosexuals are human too hand since everyone is born equal and free there should be no reason that should

School Calendar Change Essay Example | Topics and Well Written Essays - 250 words

School Calendar Change - Essay Example Teachers have raised concerns over the effects of long vacations, claiming that the time taken by students during vacation makes them forget what they had learned. As a result, reviewing the previous year material takes a significant amount of time, which, according to the educators, affects the curriculum. Cooper ((â€Å"Summer Learning Loss†) argues that summer vacation mostly affected mathematics and spelling subjects. This is because more accurate information is required from the two subjects as compared to the other tested skill subjects. Cooper goes on to defend his argument by stating that students are more likely to practice reading than performing mathematical calculations on their own. Another major effect of long summer holidays, as noted by Cooper (â€Å"The Effects of Summer Vacation†), relates to students with disabilities. The students require continuous study or instruction period to be able to understand better. The summer programs ought to help the disadvantaged students notably by ensuring that their studies are never interrupted for long. Students who speak languages other than English have also been affected by the calendar, because catching up after the long summer holidays is difficult. Cooper also notes that the scores of students are lower after the long summer vacations, the loss being equated to one month according to past studies. According to Cooper (â€Å"The Effects of Summer Vacation†), a new study program will help solve all the concerns raised by the old calendar. When short holidays are spread out across the year, they better serve the intended purpose. Considering all the above arguments, it can be stated that our school district has to adopt the new

Imperial Chemical Industries Essay Example | Topics and Well Written Essays - 2000 words

Imperial Chemical Industries - Essay Example The technology could either be innovative products that satisfy customer needs and wants or technology that offers cost competitiveness (Annual Report and Accounts 2005, 149; Science & Technology, online). A few factors in the economical environment are influential on profitability, especially since ICI operates worldwide in over 50 countries. They include domestic and international recession, tariffs and trade barriers, exchange controls, fluctuations in national currencies, foreign exchange exposure, and cyclical fluctuations of the industries and economies in which its businesses operate (Annual Report and Accounts 2005, 149-150; Investor Relations: Financial Performance: Risk Management, online). There are many factors in the legal environment that are particularly influential on profitability. They arise from worldwide operation, exposure to consumer markets, rules governing fair competition and corporate governance, and contractual obligations. ICI worldwide operation requires compliance with a range of foreign laws, regulations and standards that are expensive. Moreover, the difficulty of enforcing legal claims and agreements through some foreign legal systems will also affect profitability. Lastly, unforeseen changes in local laws, regulations, and standards in developing countries could affect ICI's profitability (Annual Report and Accounts 2005, 150). ICI's exposure to consumer markets exposes it to legal risks, regulation and potential liabilities from product liability claims asserted by consumers, which could have an adverse effect on profitability. A significant proportion of ICI's products is sold directly or indirectly to end-user consumers, even if ICI does not itself provide these products directly to consumers. Specifically, the laws and regulations to which ICI are exposed are environmental, health, and safety. Environmental, health, and safety laws and regulations include those concerning pollution, the health and safety of employees, protection of the public, protection of the environment and the generation, storage, handling, transportation, treatment, disposal and remediation of hazardous substances and waste materials. These regulations and standards are becoming increasingly stringent. ICI is also subject to inspections and monitoring by the relevant enforcement authorities. ICI also requires relevant permits and a pprovals for its operations that require compliance with their terms and which may be subject to renewal, modification and, in some circumstances, revocation. Violations of applicable laws, regulations and standards, could result in losses in the form of damages, fines or other sanctions, increased costs of compliance as well as reputational damage (Annual Report and Accounts 2005, 151). With regard to environmental laws and regulations, ICI is subject to soil and groundwater remediation, that in the future may require it to take action to correct effects on the environment of prior disposal or release of chemical substances. With regard to safety and health laws and regulations, The Glidden Company (Glidden), a wholly owned subsidiary

Radio Resource Management in OFDMA Networks

Radio Resource Management in OFDMA Networks 1 Introduction The convenience and popularity of wireless technology has now extended into multimedia communications, where it poses a unique challenge for transmitting high rate voice, image, and data signals simultaneously, synchronously, and virtually error-free. That challenge is currently being met through Orthogonal Frequency Division Multiplexing (OFDM), an interface protocol that divides incoming data streams into sub-streams with overlapping frequencies that can then be transmitted in parallel over orthogonal subcarriers [2,3]. To allow multiple accesses in OFDM , Orthogonal Frequency Division Multiple Access (OFDMA) was introduced. Relaying techniques, along with OFDMA, are used to achieve high data rate and high spectral efficiency. 1.1 Orthogonal Frequency Division Multiple Access OFDMA, an interface protocol combining features of OFDM and frequency division multiple access (FDMA)., was developed to move OFDM technology from a fixed-access wireless system to a true cellular system with mobility with same underlying technology, but more flexibility was defined in the operation of the system [1,8]. In OFDMA, subcarriers are grouped into larger units, referred to as sub-channels, and these sub-channels are further grouped into bursts which can be allocated to wireless users [4]. 1.2 Relay-Enhanced Networks In cellular systems, a way to achieve remarkable increase in data rate, but without claiming for more bandwidth, is to shrink cell sizes, however, with smaller cells more base stations (BSs) are needed to cover a same area due to which deployment and networking of new BSs acquire significant costs [5]. An alternative solution to this problem is to deploy smart relay stations (RSs), which can communication with each other and with BSs through wireless connections reducing systems cost. A relay station (RS), also called repeater or multi-hop station, is a radio system that helps to improve coverage and capacity of a base station (BS) and the resulting networks employing relay stations are sometimes called cooperative networks [6]. 1.3 Technological Requirement The continuously evolving wireless multimedia services push the telecommunication industries to set a very high data rate requirement for next generation mobile communication systems. As spectrum resource becomes very scarce and expensive, how to utilize this resource wisely to fulfil high quality user experiences is a very challenging research topic. Orthogonal frequency-division multiple access (OFDMA)-based RRM schemes together with relaying techniques allocate different portions of radio resources to different users in both the frequency and time domains and offers a promising technology for providing ubiquitous high-data-rate coverage with comparatively low cost than deploying multiple base stations [5]. Although wireless services are the demand of future due to their mobility and low cost infrastructure but along with this they suffer serious channel impairments. In particular, the channel suffers from frequency selective fading and distance dependent fading (i.e., large-scale fading) [1, 8]. While frequency selective fading results in inter-symbol-interference (ISI), large-scale fading attenuates the transmitted signal below a level at which it can be correctly decoded. Orthogonal Frequency-Division Multiple Access (OFDMA) relay-enhanced cellular network, the integration of multi-hop relaying with OFDMA infrastructure, has become one of the most promising solutions for next-generation wireless communications. 1.3.1 Frequency Selective Fading In wireless communications, the transmitted signal is typically reaching the receiver through multiple propagation paths (reflections from buildings, etc.), each having a different relative delay and amplitude. This is called multipath propagation and causes different parts of the transmitted signal spectrum to be attenuated differently, which is known as frequency-selective fading. In addition to this, due to the mobility of transmitter and/or receiver or some other time-varying characteristics of the transmission environment, the principal characteristics of the wireless channel change in time which results in time-varying fading of the received signal [9]. 1.3.2 Large Scale Fading Large scale fading is explained by the gradual loss of received signal power (since it propagates in all directions) with transmitter-receiver (T-R) separation distance. These phenomenonss cause attenuation in the signal and decrease in its power. To overcome this we use diversity and multi-hop relaying. 1.3.3 Diversity Diversity refers to a method for improving the reliability of a message signal by using two or morecommunication channelswith different characteristics. Diversity plays an important role in combatingfadingandco-channel interferenceand avoidingerror bursts. It is based on the fact that individual channels experience different levels of fading and interference. Multiple versions of the same signal may be transmitted and/or received and combined in the receiver [10]. 1.4 Proposed Simulation Model We developed a simulation model in which each user-pair is allocated dynamically a pair of relay and subcarrier in order to maximize its achievable sum-rate while satisfying the minimum rate requirement. The algorithm and the results of the simulation model are given in chapter 4. 1.5 Objectives The objective of our project is to have a detail overview of the literature regarding Orthogonal Frequency Division Multiple Access (OFDMA), Radio Resource Management (RRM) and Relaying techniques. After literature review we developed a simulation framework in which we will try to use minimum resources to get maximum throughput by using dynamic resource allocation. 1.6 Tools For the design and implementation of proposed Algorithm, we have used the following tools MATLAB Smart Draw Corel Draw 1.7 Overview Chapter 2 contains the literature review. It explains the basic principles of OFDMA, Radio Resource Management (RRM) and the relaying techniques. Chapter 3 explains the implementation of OFDM generation and reception that how an OFDM signal is generated and transmitted through the channel and how it is recovered at the receiver. Chapter 4 could be considered as the main part of thesis. It focuses on the simulation framework and the code. We have followed the paper â€Å"Subcarrier Allocation for multiuser two-way OFDMA Relay networks with Fairness Constraints†. In this section we have tried to implement the Dynamic Resource Allocation algorithm in order to achieve the maximum sum rate. Results are also discussed at the end of the end of the chapter. 2 Literature Review Introduction: First section of this Chapter gives a brief overview about OFDMA.OFDMA basically is the combination of Orthogonal Frequency Division Multiplexing (OFDM) and Frequency Division Multiplexing Access (FDMA).OFDMA provides high data rates even through multipath fading channels. In order to understand OFDMA, we must have brief introduction to Modulation, Multiple Access, Propagation mechanisms, its effects and its impairments while using OFDMA. 2.1 Modulation Modulation is the method of mapping data with change in carrier phase, amplitude, frequency or the combination [11]. There are two types of modulation techniques named as Single Carrier Modulation (SCM) Transmission Technique or Multicarrier Modulation (MCM) Transmission Technique. [12] Single Carrier Modulation (SCM) In single carrier transmission modulation (SCM) transmission, information is modulated using adjustment of frequency, phase and amplitude of a single carrier [12]. Multi Carrier Modulation (MCM) In multicarrier modulation transmission, input bit stream is split into several parallel bit streams then each bit stream simultaneously modulates with several sub-carriers (SCs) [12]. 2.2 Multiplexing Multiplexing is the method of sharing bandwidth and resources with other data channels. Multiplexing is sending multiple signals or streams of information on a carrier at the same time in the form of a single, complex signal and then recovering the separate signals at the receiving end [13]. 2.2.1 Analog Transmission In analog transmission, signals are multiplexed using frequency division multiplexing (FDM), in which the carrier bandwidth is divided into sub channels of different frequency widths,and each signal is carried at the same time in parallel. 2.2.2 Digital Transmission In digital transmission, signals are commonly multiplexed using time-division multiplexing (TDM), in which the multiple signals are carried over the same channel in alternating time slots. 2.2.3 Need for OFDMA General wireless cellular systems are multi-users systems. We have limited radio resources as limited bandwidth and limited number of channels. The radio resources must be shared among multiple users. So OFDM is a better choice in this case. OFDM is the combination of modulation and multiplexing. It may be a modulation technique if we analyze the relation between input and output signals. It may be a multiplexing technique if we analyze the output signal which is the linear sum of modulated signal. In OFDM the signal is firstly split into sub channels, modulated and then re-multiplexed to create OFDM carrier. The spacing between carriers is such that they are orthogonal to one another. Therefore there is no need of guard band between carriers. In this way we are saving the bandwidth and utilizing our resources efficiently. 2.3 Radio Propagation Mechanisms There are 3 propagation mechanisms: Reflection, Diffraction and Scattering. These 3 phenomenon cause distortion in radio signal which give rise to propagation losses and fading in signals [14]. 2.3.1 Reflection Reflection occurs when a propagating Electro-Magnetic (EM) wave impinges upon an object which has very large dimensions as compared to the wavelength of the propagating wave. Reflections occur from the surface of the earth and from buildings and walls. 2.3.2 Diffraction When the radio path between the transmitter and receiver is obstructed by a surface that has sharp irregularities (edges), diffraction occurs. The secondary waves resulting from the obstructing surface are present throughout the space and even behind the obstacle, giving rise to a bending of waves around the obstacle, even when a line-of-sight path does not exist between transmitter and receiver. At high frequencies, diffraction, like reflection, depends on the geometry of the object, as well as the amplitude, phase and polarization of the incident wave at the point of diffraction. 2.3.3 Scattering When the medium through which the wave travels consists of objects with dimensions that are small compared to the wavelength, and where the number of obstacles per unit volume is large. Scattered waves are produced by rough surfaces, small objects or by other irregularities in the channel. In practice, foliage, street signs and lamp posts produce scattering in a mobile radio communications system. 2.4 Effects of Radio Propagation Mechanisms The three basic propagation mechanisms namely reflection, diffraction and scattering as we have explained above affect on the signal as it passes through the channel. These three radio propagation phenomena can usually be distinguished as large-scale path loss, shadowing and multipath fading [14][15]. 2.4.1 Path Loss Path Lossis the attenuation occurring by an electromagnetic wave in transit from a transmitter to a receiver in a telecommunication system. In simple words, it governs the deterministic attenuation power depending only upon the distance between two communicating entities. It is considered as large scale fading because it does not change rapidly. 2.4.2 Shadowing Shadowingis the result of movement of transmitter, receiver or any channel component referred to as (obstacles). Shadowing is a statistical parameter. Shadowing follows a log-normal distribution about the values governed by path loss. Although shadowing depends heavily upon the channel conditions and density of obstacles in the channel, it is also normally considered a large scale fading component alongside path loss. 2.4.3 Multipath Fading Multipath Fadingis the result of multiple propagation paths which are created by reflection, diffraction and scattering. When channel has multiple paths. Each of the paths created due to these mechanisms may have its characteristic power, delay and phase. So receiver will be receiving a large number of replicas of initially transmitted signal at each instant of time. The summation of these signals at receiver may cause constructive or destructive interferences depending upon the delays and phases of multiple signals. Due to its fast characteristic nature, multipath fading is called small scale fading. 2.5 Orthogonal Frequency Division Multiplexing (OFDM) Orthogonal Frequency Division Multiplexing (OFDM) is an efficient multicarrier modulation that is robust to multi-path radio channel impairments [15]. Now-a-days it is widely accepted that OFDM is the most promising scheme in future high data-rate broadband wireless communication systems. OFDM is a special case of MCM transmission. In OFDM, high data rate input bit stream or data is first converted into several parallel bit stream, than each low rate bit stream is modulated with subcarrier. The several subcarriers are closely spaced. However being orthogonal they do not interfere with each other. 2.5.1 Orthognality Signals are orthogonal if they are mutually independent of each other. Orthogonality is a property that allows multiple information signals to be transmitted perfectly over a common channel and detected, without interference. Loss of orthogonality results in blurring between these information signals and degradation in communications. Many common multiplexing schemes are inherently orthogonal. The term OFDM has been reserved for a special form of FDM. The subcarriers in an OFDM signal are spaced as close as is theoretically possible while maintain orthogonality between them.In FDM there needs a guard band between channels to avoid interference between channels. The addition of guard band between channels greatly reduces the spectral efficiency. In OFDM, it was required to arrange sub carriers in such a way that the side band of each sub carrier overlap and signal is received without interference. The sub-carriers (SCs) must be orthogonal to each other, which eliminates the guard band and improves the spectral efficiency . 2.5.2 Conditions of orthogonality 2.5.2.1 Orthogonal Vectors Vectors A and B are two different vectors, they are said to be orthogonal if their dot product is zero 2.6 OFDM GENERATION AND RECEPTION OFDM signals are typically generated digitally due to the complexity of implementation in the analog domain. The transmission side is used to transmit digital data by mapping the subcarrier amplitude and phase. It then transforms this spectral representation of the data into the time domain using an Inverse Discrete Fourier Transform (IDFT) but due to much more computational efficiency in Inverse Fast Fourier Transform (IFFT), IFFT is used in all practical systems. The receiver side performs the reverse operations of the transmission side, mixing the RF signal to base band for processing, and then a Fast Fourier Transform (FFT) is employed to analyze the signal in the frequency domain. The demodulation of the frequency domain signal is then performed in order to obtain the transmitted digital data. The IFFT and the FFT are complementary function and the most suitable term depends on whether the signal is being recovered or transmitted but the cases where the signal is independent of this distinction then these terms can be used interchangeably [15]. 2.6.1 OFDM Block Diagram 2.6.2 Implementation of OFDM Block Diagram 2.6.2.1 Serial to Parallel Conversion: In an OFDM system, each channel can be broken down into number of sub-carriers. The use of sub-carriers can help to increase the spectral efficiency but requires additional processing by the transmitter and receiver which is necessary to convert a serial bit stream into several parallel bit streams to be divided among the individual carriers. This makes the processing faster as well as is used for mapping symbols on sub-carriers. 2.6.2.2 Modulation of Data: Once the bit stream has been divided among the individual sub-carriers by the use of serial to parallel converter, each sub-carrier is modulated using 16 QAM scheme as if it was an individual channel before all channels are combined back together and transmitted as a whole. 2.6.2.3 Inverse Fourier Transform: The role of the IFFT is to modulate each sub-channel onto the appropriate carrier thus after the required spectrum is worked out, an inverse Fourier transform is used to find the corresponding time domain waveform. 2.6.2.4 Parallel to Serial Conversion: Once the inverse Fourier transform has been done each symbol must be combined together and then transmitted as one signal. Thus, the parallel to serial conversion stage is the process of summing all sub-carriers and combining them into one signal 2.6.2.5 Channel: The OFDM signal is then transmitted over a channel with AWGN having SNR of 10 dB. 2.6.2.6 Receiver: The receiver basically does the reverse operations to the transmitter. The FFT of each symbol is taken to find the original transmitted spectrum. The phase angle of each transmission carrier is then evaluated and converted back to the data word by demodulating the received phase. The data words are then combined back to the same word size as the original data. 2.7 OFDMA in a broader perspective OFDM is a modulation scheme that allows digital data to be efficiently and reliably transmitted over a radio channel, even in multipath environments [17]. OFDM transmits data by using a large number of narrow bandwidth carriers. These carriers are regularly spaced in frequency, forming a block of spectrum. The frequency spacing and time synchronization of the carriers is chosen in such a way that the carriers are orthogonal, meaning that they do not interfere with each other. This is despite the carriers overlapping each other in the frequency domain [18]. The name ‘OFDM is derived from the fact that the digital data is sent using many carriers, each of a different frequency (Frequency Division Multiplexing) and these carriers are orthogonal to each other [19]. 2.7.1 History of OFDMA The origins of OFDM development started in the late 1950s with the introduction of Frequency Division Multiplexing (FDM) for data communications. In 1966 Chang patented the structure of OFDM and published the concept of using orthogonal overlapping multi-tone signals for data communications. In 1971 Weinstein introduced the idea of using a Discrete Fourier Transform (DFT) for Implementation of the generation and reception of OFDM signals, eliminating the requirement for banks of analog subcarrier oscillators. This presented an opportunity for an easy implementation of OFDM, especially with the use of Fast Fourier Transforms (FFT), which are an efficient implementation of the DFT. This suggested that the easiest implementation of OFDM is with the use of Digital Signal Processing (DSP), which can implement FFT algorithms. It is only recently that the advances in integrated circuit technology have made the implementation of OFDM cost effective. The reliance on DSP prevented the wide spread use of OFDM during the early development of OFDM. It wasnt until the late 1980s that work began on the development of OFDM for commercial use, with the introduction of the Digital Audio Broadcasting (DAB) system. 2.7.2 Advantages using OFDMA There are some advantages using OFDMA. OFDM is a highly bandwidth efficient scheme because different sub-carriers are orthogonal but they are overlapping. Flexible and can be made adaptive; different modulation schemes for subcarriers, bit loading, adaptable bandwidth/data rates possible. Has excellent ICI performance because of addition of cyclic prefix. In OFDM equalization is performed in frequency domain which becomes very easy as compared to the time domain equalization. Very good at mitigating the effects of delay spread. Due to the use of many sub-carriers, the symbol duration on the sub-carriers is increased, relative to delay spread. ISI is avoided through the use of guard interval. Resistant to frequency selective fading as compared to single carrier system. Used for high data rate transmission. OFDMA provides flexibility of deployment across a variety of frequency bands with little need for modification is of paramount importance. A single frequency network can be used to provide excellent coverage and good frequency re-use. OFDMA offers frequency diversity by spreading the carriers all over the used spectrum. 2.7.3 Challenges using OFDMA These are the difficulties we have to face while using OFDMA [20][21][22], The OFDM signal suffers from a very high peak to average power ratio (PAPR) therefore it requires transmitter RF power amplifiers to be sufficiently linear in the range of high input power. Sensitive to carrier frequency offset, needs frequency offset correction in the receiver. Sensitive to oscillator phase noise, clean and stable oscillator required. The use of guard interval to mitigate ISI affects the bandwidth efficiency. OFDM is sensitive to Doppler shift frequency errors offset the receiver and if not corrected the orthogonality between the carriers is degraded. If only a few carriers are assigned to each user the resistance to selective fading will be degraded or lost. It has a relatively high sensitivity to frequency offsets as this degrades the orthogonality between the carriers. It is sensitive to phase noise on the oscillators as this degrades the orthogonaility between the carriers. 2.7.4 Comparison with CDMA in terms of benefits 2.7.4.2 CDMA Advantages: CDMA has some advantages over OFDMA [22], Not as complicated to implement as OFDM based systems. As CDMA has a wide bandwidth, it is difficult to equalise the overall spectrum significant levels of processing would be needed for this as it consists of a continuous signal and not discrete carriers. Not as easy to aggregate spectrum as for OFDM. 2.7.5 OFDMA in the Real World: UMTS, the European standard for the 3G cellular mobile communications, and IEEE 802.16, a broadband wireless access standard for metropolitan area networks (MAN), are two live examples for industrial support of OFDMA. Table 1 shows the basic parameters of these two systems. Table 1. OFDMA system parameters in the UMTS and IEEE 802.16 standards 2.8 Radio Resource Management In second section of this chapter we will discuss radio resource management schemes, why we need them and how they improve the efficiency of the network. Radio resource management is the system level control of co-channel interference and other radio transmission characteristics in wireless communication systems. Radio resource management involves algorithms and strategies for controlling parameters such as Transmit power Sub carrier allocation Data rates Handover criteria Modulation scheme Error coding scheme, etc 2.8.1 Study of Radio Resource Management End-to-end reconfigurability has a strong impact on all aspects of the system, ranging from the terminal, to the air interface, up to the network side. Future network architectures must be flexible enough to support scalability as well as reconfigurable network elements, in order to provide the best possible resource management solutions in hand with cost effective network deployment. The ultimate aim is to increase spectrum efficiency through the use of more flexible spectrum allocation and radio resource management schemes, although suitable load balancing mechanisms are also desirable to maximize system capacity, to optimize QoS provision, and to increase spectrum efficiency. Once in place, mobile users will benefit from this by being able to access required services when and where needed, at an affordable cost. From an engineering point of view, the best possible solution can only be achieved when elements of the radio network are properly configured and suitable radio resource m anagement approaches/algorithms are applied. In other words, the efficient management of the whole reconfiguration decision process is necessary, in order to exploit the advantages provided by reconfigurability. For this purpose, future mobile radio networks must meet the challenge of providing higher quality of service through supporting increased mobility and throughput of multimedia services, even considering scarcity of spectrum resources. Although the size of frequency spectrum physically limits the capacity of radio networks, effective solutions to increase spectrum efficiency can optimize usage of available capacity. Through inspecting the needs of relevant participants in a mobile communication system, i.e., the Terminal, User, Service and Network, effective solutions can be used to define the communication configuration between the Terminal and Network, dependent on the requirements of Services demanded by Users. In other words, it is necessary to identify proper communications mechanisms between communications apparatus, based on the characteristics of users and their services. This raises further questions about how to manage traffic in heterogeneous networks in an efficient way. 2.8.2 Methods of RRM 2.8.2.1 Network based functions Admission control (AC) Load control (LC) Packet scheduler (PS) Resource Manager (RM) Admission control In the decision procedure AC will use threshold form network planning and from Interference measurements. The new connection should not impact the planned coverage and quality of existing Connections. (During the whole connection time.) AC estimates the UL and DL load increase which new connection would produce. AC uses load information from LC and PC. Load change depends on attributes of RAB: traffic and quality parameters. If UL or DL limit threshold is exceeded the RAB is not admitted. AC derives the transmitted bit rate, processing gain, Radio link initial quality parameters, target BER, BLER, Eb/No, SIR target. AC manages the bearer mapping The L1 parameters to be used during the call. AC initiates the forced call release, forced inter-frequency or intersystem handover. Load control Reason of load control Optimize the capacity of a cell and prevent overload The interference main resource criteria. LC measures continuously UL and DL interference. RRM acts based on the measurements and parameters from planning Preventive load control In normal conditions LC takes care that the network is not overloaded and remains Stable. Overload condition . LC is responsible for reducing the load and bringing the network back into operating area. Fast LC actions in BTS Lower SIR target for the uplink inner-loop PC. LC actions located in the RNC. Interact with PS and throttle back packet data traffic. Lower bit rates of RT users.(speech service or CS data). WCDMA interfrequency or GSM intersystem handover. Drop single calls in a controlled manner. 2.8.2.3 Connection based functions Handover Control (HC) Power Control (PC) Power control Uplink open loop power control. Downlink open loop power control. Power in downlink common channels. Uplink inner (closed) loop power control. Downlink inner (closed) loop power control. Outer loop power control. Power control in compressed mode. Handover Intersystem handover. Intrafrequency handover. Interfrequency handover. Intersystem handover. Hard handover (HHO). All the old radio links of an MS are released before the new radio links are established. Soft handover (SHO) SMS is simultaneously controlled by two or more cells belonging to different BTS of the same RNC or to different RNC. MS is controlled by at least two cells under one BTS. Mobile evaluated handover (MEHO) The UE mai Radio Resource Management in OFDMA Networks Radio Resource Management in OFDMA Networks 1 Introduction The convenience and popularity of wireless technology has now extended into multimedia communications, where it poses a unique challenge for transmitting high rate voice, image, and data signals simultaneously, synchronously, and virtually error-free. That challenge is currently being met through Orthogonal Frequency Division Multiplexing (OFDM), an interface protocol that divides incoming data streams into sub-streams with overlapping frequencies that can then be transmitted in parallel over orthogonal subcarriers [2,3]. To allow multiple accesses in OFDM , Orthogonal Frequency Division Multiple Access (OFDMA) was introduced. Relaying techniques, along with OFDMA, are used to achieve high data rate and high spectral efficiency. 1.1 Orthogonal Frequency Division Multiple Access OFDMA, an interface protocol combining features of OFDM and frequency division multiple access (FDMA)., was developed to move OFDM technology from a fixed-access wireless system to a true cellular system with mobility with same underlying technology, but more flexibility was defined in the operation of the system [1,8]. In OFDMA, subcarriers are grouped into larger units, referred to as sub-channels, and these sub-channels are further grouped into bursts which can be allocated to wireless users [4]. 1.2 Relay-Enhanced Networks In cellular systems, a way to achieve remarkable increase in data rate, but without claiming for more bandwidth, is to shrink cell sizes, however, with smaller cells more base stations (BSs) are needed to cover a same area due to which deployment and networking of new BSs acquire significant costs [5]. An alternative solution to this problem is to deploy smart relay stations (RSs), which can communication with each other and with BSs through wireless connections reducing systems cost. A relay station (RS), also called repeater or multi-hop station, is a radio system that helps to improve coverage and capacity of a base station (BS) and the resulting networks employing relay stations are sometimes called cooperative networks [6]. 1.3 Technological Requirement The continuously evolving wireless multimedia services push the telecommunication industries to set a very high data rate requirement for next generation mobile communication systems. As spectrum resource becomes very scarce and expensive, how to utilize this resource wisely to fulfil high quality user experiences is a very challenging research topic. Orthogonal frequency-division multiple access (OFDMA)-based RRM schemes together with relaying techniques allocate different portions of radio resources to different users in both the frequency and time domains and offers a promising technology for providing ubiquitous high-data-rate coverage with comparatively low cost than deploying multiple base stations [5]. Although wireless services are the demand of future due to their mobility and low cost infrastructure but along with this they suffer serious channel impairments. In particular, the channel suffers from frequency selective fading and distance dependent fading (i.e., large-scale fading) [1, 8]. While frequency selective fading results in inter-symbol-interference (ISI), large-scale fading attenuates the transmitted signal below a level at which it can be correctly decoded. Orthogonal Frequency-Division Multiple Access (OFDMA) relay-enhanced cellular network, the integration of multi-hop relaying with OFDMA infrastructure, has become one of the most promising solutions for next-generation wireless communications. 1.3.1 Frequency Selective Fading In wireless communications, the transmitted signal is typically reaching the receiver through multiple propagation paths (reflections from buildings, etc.), each having a different relative delay and amplitude. This is called multipath propagation and causes different parts of the transmitted signal spectrum to be attenuated differently, which is known as frequency-selective fading. In addition to this, due to the mobility of transmitter and/or receiver or some other time-varying characteristics of the transmission environment, the principal characteristics of the wireless channel change in time which results in time-varying fading of the received signal [9]. 1.3.2 Large Scale Fading Large scale fading is explained by the gradual loss of received signal power (since it propagates in all directions) with transmitter-receiver (T-R) separation distance. These phenomenonss cause attenuation in the signal and decrease in its power. To overcome this we use diversity and multi-hop relaying. 1.3.3 Diversity Diversity refers to a method for improving the reliability of a message signal by using two or morecommunication channelswith different characteristics. Diversity plays an important role in combatingfadingandco-channel interferenceand avoidingerror bursts. It is based on the fact that individual channels experience different levels of fading and interference. Multiple versions of the same signal may be transmitted and/or received and combined in the receiver [10]. 1.4 Proposed Simulation Model We developed a simulation model in which each user-pair is allocated dynamically a pair of relay and subcarrier in order to maximize its achievable sum-rate while satisfying the minimum rate requirement. The algorithm and the results of the simulation model are given in chapter 4. 1.5 Objectives The objective of our project is to have a detail overview of the literature regarding Orthogonal Frequency Division Multiple Access (OFDMA), Radio Resource Management (RRM) and Relaying techniques. After literature review we developed a simulation framework in which we will try to use minimum resources to get maximum throughput by using dynamic resource allocation. 1.6 Tools For the design and implementation of proposed Algorithm, we have used the following tools MATLAB Smart Draw Corel Draw 1.7 Overview Chapter 2 contains the literature review. It explains the basic principles of OFDMA, Radio Resource Management (RRM) and the relaying techniques. Chapter 3 explains the implementation of OFDM generation and reception that how an OFDM signal is generated and transmitted through the channel and how it is recovered at the receiver. Chapter 4 could be considered as the main part of thesis. It focuses on the simulation framework and the code. We have followed the paper â€Å"Subcarrier Allocation for multiuser two-way OFDMA Relay networks with Fairness Constraints†. In this section we have tried to implement the Dynamic Resource Allocation algorithm in order to achieve the maximum sum rate. Results are also discussed at the end of the end of the chapter. 2 Literature Review Introduction: First section of this Chapter gives a brief overview about OFDMA.OFDMA basically is the combination of Orthogonal Frequency Division Multiplexing (OFDM) and Frequency Division Multiplexing Access (FDMA).OFDMA provides high data rates even through multipath fading channels. In order to understand OFDMA, we must have brief introduction to Modulation, Multiple Access, Propagation mechanisms, its effects and its impairments while using OFDMA. 2.1 Modulation Modulation is the method of mapping data with change in carrier phase, amplitude, frequency or the combination [11]. There are two types of modulation techniques named as Single Carrier Modulation (SCM) Transmission Technique or Multicarrier Modulation (MCM) Transmission Technique. [12] Single Carrier Modulation (SCM) In single carrier transmission modulation (SCM) transmission, information is modulated using adjustment of frequency, phase and amplitude of a single carrier [12]. Multi Carrier Modulation (MCM) In multicarrier modulation transmission, input bit stream is split into several parallel bit streams then each bit stream simultaneously modulates with several sub-carriers (SCs) [12]. 2.2 Multiplexing Multiplexing is the method of sharing bandwidth and resources with other data channels. Multiplexing is sending multiple signals or streams of information on a carrier at the same time in the form of a single, complex signal and then recovering the separate signals at the receiving end [13]. 2.2.1 Analog Transmission In analog transmission, signals are multiplexed using frequency division multiplexing (FDM), in which the carrier bandwidth is divided into sub channels of different frequency widths,and each signal is carried at the same time in parallel. 2.2.2 Digital Transmission In digital transmission, signals are commonly multiplexed using time-division multiplexing (TDM), in which the multiple signals are carried over the same channel in alternating time slots. 2.2.3 Need for OFDMA General wireless cellular systems are multi-users systems. We have limited radio resources as limited bandwidth and limited number of channels. The radio resources must be shared among multiple users. So OFDM is a better choice in this case. OFDM is the combination of modulation and multiplexing. It may be a modulation technique if we analyze the relation between input and output signals. It may be a multiplexing technique if we analyze the output signal which is the linear sum of modulated signal. In OFDM the signal is firstly split into sub channels, modulated and then re-multiplexed to create OFDM carrier. The spacing between carriers is such that they are orthogonal to one another. Therefore there is no need of guard band between carriers. In this way we are saving the bandwidth and utilizing our resources efficiently. 2.3 Radio Propagation Mechanisms There are 3 propagation mechanisms: Reflection, Diffraction and Scattering. These 3 phenomenon cause distortion in radio signal which give rise to propagation losses and fading in signals [14]. 2.3.1 Reflection Reflection occurs when a propagating Electro-Magnetic (EM) wave impinges upon an object which has very large dimensions as compared to the wavelength of the propagating wave. Reflections occur from the surface of the earth and from buildings and walls. 2.3.2 Diffraction When the radio path between the transmitter and receiver is obstructed by a surface that has sharp irregularities (edges), diffraction occurs. The secondary waves resulting from the obstructing surface are present throughout the space and even behind the obstacle, giving rise to a bending of waves around the obstacle, even when a line-of-sight path does not exist between transmitter and receiver. At high frequencies, diffraction, like reflection, depends on the geometry of the object, as well as the amplitude, phase and polarization of the incident wave at the point of diffraction. 2.3.3 Scattering When the medium through which the wave travels consists of objects with dimensions that are small compared to the wavelength, and where the number of obstacles per unit volume is large. Scattered waves are produced by rough surfaces, small objects or by other irregularities in the channel. In practice, foliage, street signs and lamp posts produce scattering in a mobile radio communications system. 2.4 Effects of Radio Propagation Mechanisms The three basic propagation mechanisms namely reflection, diffraction and scattering as we have explained above affect on the signal as it passes through the channel. These three radio propagation phenomena can usually be distinguished as large-scale path loss, shadowing and multipath fading [14][15]. 2.4.1 Path Loss Path Lossis the attenuation occurring by an electromagnetic wave in transit from a transmitter to a receiver in a telecommunication system. In simple words, it governs the deterministic attenuation power depending only upon the distance between two communicating entities. It is considered as large scale fading because it does not change rapidly. 2.4.2 Shadowing Shadowingis the result of movement of transmitter, receiver or any channel component referred to as (obstacles). Shadowing is a statistical parameter. Shadowing follows a log-normal distribution about the values governed by path loss. Although shadowing depends heavily upon the channel conditions and density of obstacles in the channel, it is also normally considered a large scale fading component alongside path loss. 2.4.3 Multipath Fading Multipath Fadingis the result of multiple propagation paths which are created by reflection, diffraction and scattering. When channel has multiple paths. Each of the paths created due to these mechanisms may have its characteristic power, delay and phase. So receiver will be receiving a large number of replicas of initially transmitted signal at each instant of time. The summation of these signals at receiver may cause constructive or destructive interferences depending upon the delays and phases of multiple signals. Due to its fast characteristic nature, multipath fading is called small scale fading. 2.5 Orthogonal Frequency Division Multiplexing (OFDM) Orthogonal Frequency Division Multiplexing (OFDM) is an efficient multicarrier modulation that is robust to multi-path radio channel impairments [15]. Now-a-days it is widely accepted that OFDM is the most promising scheme in future high data-rate broadband wireless communication systems. OFDM is a special case of MCM transmission. In OFDM, high data rate input bit stream or data is first converted into several parallel bit stream, than each low rate bit stream is modulated with subcarrier. The several subcarriers are closely spaced. However being orthogonal they do not interfere with each other. 2.5.1 Orthognality Signals are orthogonal if they are mutually independent of each other. Orthogonality is a property that allows multiple information signals to be transmitted perfectly over a common channel and detected, without interference. Loss of orthogonality results in blurring between these information signals and degradation in communications. Many common multiplexing schemes are inherently orthogonal. The term OFDM has been reserved for a special form of FDM. The subcarriers in an OFDM signal are spaced as close as is theoretically possible while maintain orthogonality between them.In FDM there needs a guard band between channels to avoid interference between channels. The addition of guard band between channels greatly reduces the spectral efficiency. In OFDM, it was required to arrange sub carriers in such a way that the side band of each sub carrier overlap and signal is received without interference. The sub-carriers (SCs) must be orthogonal to each other, which eliminates the guard band and improves the spectral efficiency . 2.5.2 Conditions of orthogonality 2.5.2.1 Orthogonal Vectors Vectors A and B are two different vectors, they are said to be orthogonal if their dot product is zero 2.6 OFDM GENERATION AND RECEPTION OFDM signals are typically generated digitally due to the complexity of implementation in the analog domain. The transmission side is used to transmit digital data by mapping the subcarrier amplitude and phase. It then transforms this spectral representation of the data into the time domain using an Inverse Discrete Fourier Transform (IDFT) but due to much more computational efficiency in Inverse Fast Fourier Transform (IFFT), IFFT is used in all practical systems. The receiver side performs the reverse operations of the transmission side, mixing the RF signal to base band for processing, and then a Fast Fourier Transform (FFT) is employed to analyze the signal in the frequency domain. The demodulation of the frequency domain signal is then performed in order to obtain the transmitted digital data. The IFFT and the FFT are complementary function and the most suitable term depends on whether the signal is being recovered or transmitted but the cases where the signal is independent of this distinction then these terms can be used interchangeably [15]. 2.6.1 OFDM Block Diagram 2.6.2 Implementation of OFDM Block Diagram 2.6.2.1 Serial to Parallel Conversion: In an OFDM system, each channel can be broken down into number of sub-carriers. The use of sub-carriers can help to increase the spectral efficiency but requires additional processing by the transmitter and receiver which is necessary to convert a serial bit stream into several parallel bit streams to be divided among the individual carriers. This makes the processing faster as well as is used for mapping symbols on sub-carriers. 2.6.2.2 Modulation of Data: Once the bit stream has been divided among the individual sub-carriers by the use of serial to parallel converter, each sub-carrier is modulated using 16 QAM scheme as if it was an individual channel before all channels are combined back together and transmitted as a whole. 2.6.2.3 Inverse Fourier Transform: The role of the IFFT is to modulate each sub-channel onto the appropriate carrier thus after the required spectrum is worked out, an inverse Fourier transform is used to find the corresponding time domain waveform. 2.6.2.4 Parallel to Serial Conversion: Once the inverse Fourier transform has been done each symbol must be combined together and then transmitted as one signal. Thus, the parallel to serial conversion stage is the process of summing all sub-carriers and combining them into one signal 2.6.2.5 Channel: The OFDM signal is then transmitted over a channel with AWGN having SNR of 10 dB. 2.6.2.6 Receiver: The receiver basically does the reverse operations to the transmitter. The FFT of each symbol is taken to find the original transmitted spectrum. The phase angle of each transmission carrier is then evaluated and converted back to the data word by demodulating the received phase. The data words are then combined back to the same word size as the original data. 2.7 OFDMA in a broader perspective OFDM is a modulation scheme that allows digital data to be efficiently and reliably transmitted over a radio channel, even in multipath environments [17]. OFDM transmits data by using a large number of narrow bandwidth carriers. These carriers are regularly spaced in frequency, forming a block of spectrum. The frequency spacing and time synchronization of the carriers is chosen in such a way that the carriers are orthogonal, meaning that they do not interfere with each other. This is despite the carriers overlapping each other in the frequency domain [18]. The name ‘OFDM is derived from the fact that the digital data is sent using many carriers, each of a different frequency (Frequency Division Multiplexing) and these carriers are orthogonal to each other [19]. 2.7.1 History of OFDMA The origins of OFDM development started in the late 1950s with the introduction of Frequency Division Multiplexing (FDM) for data communications. In 1966 Chang patented the structure of OFDM and published the concept of using orthogonal overlapping multi-tone signals for data communications. In 1971 Weinstein introduced the idea of using a Discrete Fourier Transform (DFT) for Implementation of the generation and reception of OFDM signals, eliminating the requirement for banks of analog subcarrier oscillators. This presented an opportunity for an easy implementation of OFDM, especially with the use of Fast Fourier Transforms (FFT), which are an efficient implementation of the DFT. This suggested that the easiest implementation of OFDM is with the use of Digital Signal Processing (DSP), which can implement FFT algorithms. It is only recently that the advances in integrated circuit technology have made the implementation of OFDM cost effective. The reliance on DSP prevented the wide spread use of OFDM during the early development of OFDM. It wasnt until the late 1980s that work began on the development of OFDM for commercial use, with the introduction of the Digital Audio Broadcasting (DAB) system. 2.7.2 Advantages using OFDMA There are some advantages using OFDMA. OFDM is a highly bandwidth efficient scheme because different sub-carriers are orthogonal but they are overlapping. Flexible and can be made adaptive; different modulation schemes for subcarriers, bit loading, adaptable bandwidth/data rates possible. Has excellent ICI performance because of addition of cyclic prefix. In OFDM equalization is performed in frequency domain which becomes very easy as compared to the time domain equalization. Very good at mitigating the effects of delay spread. Due to the use of many sub-carriers, the symbol duration on the sub-carriers is increased, relative to delay spread. ISI is avoided through the use of guard interval. Resistant to frequency selective fading as compared to single carrier system. Used for high data rate transmission. OFDMA provides flexibility of deployment across a variety of frequency bands with little need for modification is of paramount importance. A single frequency network can be used to provide excellent coverage and good frequency re-use. OFDMA offers frequency diversity by spreading the carriers all over the used spectrum. 2.7.3 Challenges using OFDMA These are the difficulties we have to face while using OFDMA [20][21][22], The OFDM signal suffers from a very high peak to average power ratio (PAPR) therefore it requires transmitter RF power amplifiers to be sufficiently linear in the range of high input power. Sensitive to carrier frequency offset, needs frequency offset correction in the receiver. Sensitive to oscillator phase noise, clean and stable oscillator required. The use of guard interval to mitigate ISI affects the bandwidth efficiency. OFDM is sensitive to Doppler shift frequency errors offset the receiver and if not corrected the orthogonality between the carriers is degraded. If only a few carriers are assigned to each user the resistance to selective fading will be degraded or lost. It has a relatively high sensitivity to frequency offsets as this degrades the orthogonality between the carriers. It is sensitive to phase noise on the oscillators as this degrades the orthogonaility between the carriers. 2.7.4 Comparison with CDMA in terms of benefits 2.7.4.2 CDMA Advantages: CDMA has some advantages over OFDMA [22], Not as complicated to implement as OFDM based systems. As CDMA has a wide bandwidth, it is difficult to equalise the overall spectrum significant levels of processing would be needed for this as it consists of a continuous signal and not discrete carriers. Not as easy to aggregate spectrum as for OFDM. 2.7.5 OFDMA in the Real World: UMTS, the European standard for the 3G cellular mobile communications, and IEEE 802.16, a broadband wireless access standard for metropolitan area networks (MAN), are two live examples for industrial support of OFDMA. Table 1 shows the basic parameters of these two systems. Table 1. OFDMA system parameters in the UMTS and IEEE 802.16 standards 2.8 Radio Resource Management In second section of this chapter we will discuss radio resource management schemes, why we need them and how they improve the efficiency of the network. Radio resource management is the system level control of co-channel interference and other radio transmission characteristics in wireless communication systems. Radio resource management involves algorithms and strategies for controlling parameters such as Transmit power Sub carrier allocation Data rates Handover criteria Modulation scheme Error coding scheme, etc 2.8.1 Study of Radio Resource Management End-to-end reconfigurability has a strong impact on all aspects of the system, ranging from the terminal, to the air interface, up to the network side. Future network architectures must be flexible enough to support scalability as well as reconfigurable network elements, in order to provide the best possible resource management solutions in hand with cost effective network deployment. The ultimate aim is to increase spectrum efficiency through the use of more flexible spectrum allocation and radio resource management schemes, although suitable load balancing mechanisms are also desirable to maximize system capacity, to optimize QoS provision, and to increase spectrum efficiency. Once in place, mobile users will benefit from this by being able to access required services when and where needed, at an affordable cost. From an engineering point of view, the best possible solution can only be achieved when elements of the radio network are properly configured and suitable radio resource m anagement approaches/algorithms are applied. In other words, the efficient management of the whole reconfiguration decision process is necessary, in order to exploit the advantages provided by reconfigurability. For this purpose, future mobile radio networks must meet the challenge of providing higher quality of service through supporting increased mobility and throughput of multimedia services, even considering scarcity of spectrum resources. Although the size of frequency spectrum physically limits the capacity of radio networks, effective solutions to increase spectrum efficiency can optimize usage of available capacity. Through inspecting the needs of relevant participants in a mobile communication system, i.e., the Terminal, User, Service and Network, effective solutions can be used to define the communication configuration between the Terminal and Network, dependent on the requirements of Services demanded by Users. In other words, it is necessary to identify proper communications mechanisms between communications apparatus, based on the characteristics of users and their services. This raises further questions about how to manage traffic in heterogeneous networks in an efficient way. 2.8.2 Methods of RRM 2.8.2.1 Network based functions Admission control (AC) Load control (LC) Packet scheduler (PS) Resource Manager (RM) Admission control In the decision procedure AC will use threshold form network planning and from Interference measurements. The new connection should not impact the planned coverage and quality of existing Connections. (During the whole connection time.) AC estimates the UL and DL load increase which new connection would produce. AC uses load information from LC and PC. Load change depends on attributes of RAB: traffic and quality parameters. If UL or DL limit threshold is exceeded the RAB is not admitted. AC derives the transmitted bit rate, processing gain, Radio link initial quality parameters, target BER, BLER, Eb/No, SIR target. AC manages the bearer mapping The L1 parameters to be used during the call. AC initiates the forced call release, forced inter-frequency or intersystem handover. Load control Reason of load control Optimize the capacity of a cell and prevent overload The interference main resource criteria. LC measures continuously UL and DL interference. RRM acts based on the measurements and parameters from planning Preventive load control In normal conditions LC takes care that the network is not overloaded and remains Stable. Overload condition . LC is responsible for reducing the load and bringing the network back into operating area. Fast LC actions in BTS Lower SIR target for the uplink inner-loop PC. LC actions located in the RNC. Interact with PS and throttle back packet data traffic. Lower bit rates of RT users.(speech service or CS data). WCDMA interfrequency or GSM intersystem handover. Drop single calls in a controlled manner. 2.8.2.3 Connection based functions Handover Control (HC) Power Control (PC) Power control Uplink open loop power control. Downlink open loop power control. Power in downlink common channels. Uplink inner (closed) loop power control. Downlink inner (closed) loop power control. Outer loop power control. Power control in compressed mode. Handover Intersystem handover. Intrafrequency handover. Interfrequency handover. Intersystem handover. Hard handover (HHO). All the old radio links of an MS are released before the new radio links are established. Soft handover (SHO) SMS is simultaneously controlled by two or more cells belonging to different BTS of the same RNC or to different RNC. MS is controlled by at least two cells under one BTS. Mobile evaluated handover (MEHO) The UE mai