Ecriture Feminine

Ecriture feminine, literally â€Å"women's writing,†[1]  more closely, the writing of the female body and female disparity in language and text,[2]  is a strain of  feminist literary theory that originated in France  in the early 1970s and included foundational theorists such as  Helene Cixous,  Monique Wittig,  Luce Irigaray,[3]  Chantal Chawaf,[4][5]  and  Julia Kristeva,[6][7]  and also other writers like psychoanalytical theorist  Bracha Ettinger,[8][9]  who joined this field in the early 1990s. [10]  Generally, French feminists tended to focus their attention on language, analyzing the ways in which meaning is produced. They concluded that language as we commonly think of it is a decidedly male realm, which therefore only represents a world from the male point of view. [11] Nonetheless, the French women's movement developed in much the same way as the feminist movements elsewhere in Europe or in the United States: French women participated in consciousness-raising groups; demonstrated in the streets on the  8th of March; fought hard for women's right to choose whether to have children; raised the issue of violence against women; and struggled to change public opinion on issues concerning women and women's rights. The fact that the very first meeting of a handful of would-be feminist activists in 1970 only managed to launch an acrimonious theoretical debate, would seem to mark the situation as typically ‘French' in its apparent insistence on the primacy of theory over politics. [12] Helene Cixous  first coined  ecriture feminine  in her essay, â€Å"The Laugh of the Medusa† (1975), where she asserts â€Å"Woman must write her self: must write about women and bring women to writing, from which they have been driven away as violently as from their bodies† because their sexual pleasure has been repressed and denied expression. Inspired by Cixous' essay, a recent book titledLaughing with Medusa  (2006) analyzes the collective work of Julia Kristeva, Luce Irigaray, Bracha Ettinger and Helene Cixous. [13]  These writers are as a whole referred to by Anglophones as â€Å"the French feminists,† though Mary Klages, Associate Professor in the English Department at the University of Colorado at Boulder, has pointed out that â€Å"poststructuralist theoretical feminists† would be a more accurate term. [14]  Madeleine Gagnon is a more recent proponent. And since the aforementioned 1975 when Cixous also founded women's studies at Vincennes, she has been as a spokeswoman for the group Psychanalyse et politique and a prolific writer of texts for their publishing house, des femmes. And when asked of her own writing she says, â€Å"Je suis la ou ca parle† (â€Å"I am there where it/id/the female unconscious speaks. â€Å")  [15] American feminist critic and writer  Elaine Showalter  defines this movement as â€Å"the inscription of the feminine body and female difference in language and text. [16]  Ecriture feminine places experience before language, and privileges non-linear, cyclical writing that evades â€Å"the discourse that regulates the  phallocentric  system. â€Å"[17]  Because language is not a neutral medium, the argument can be made that it functions as an instrument of patriarchal expression. Peter Barry writes that â€Å"the female writer is seen as suffering the handicap of having to use a mediu m (prose writing) which is essentially a male instrument fashioned for male purposes†. 18]  Ecriture feminine thus exists as an antithesis of masculine writing, or as a means of escape for women,although the phallogocentric argument itself has been criticised by W. A. Borody as misrepresenting the history of philosophies of ‘’indeterminateness’’ in Western culture. Borody claims that the‘black and white’’view that the masculine=determinateness and the feminine=indeterminateness contains a degree of cultural and historical validity, but not when it is deployed to self-replicate a similar form of gender-othering it originally sought to overcome. 19]  In the words of Rosemarie Tong, â€Å"Cixous challenged women to write themselves out of the world men constructed for women. She urged women to put themselves-the unthinkable/unthought-into words. †[20] Almost everything is yet to be written by women about femininity: about their sexuality, that is, its infinite and mobile complexity; about their eroticization, sudden turn-ons of a certain minuscule-immense area of their bodies; not about destiny, but about the adventure of such and such a drive, about trips, crossings, trudges, abrupt and gradual awakenings, discoveries of a zone at once timorous and soon to be forthright. 14] With regard to phallocentric writing, Tong explains that â€Å"male sexuality, which centers on what Cixous called the â€Å"big dick†, is ultimately boring in its pointedness and singularity. Like male sexuality, masculine writing, which Cixous usually termed phallogocentric writing, is also ultimately boring† and furthermore, that â€Å"stamped with the official seal of social approval, masculine writing is too weighted down to move or change†. 20] Write, let no one hold you back, let nothing stop you: not man; not the imbecilic capitalist machinery, in which the publishing houses are the crafty, obsequiou s relayers of imperatives handed down by an economy that works against us and off our backs; not  yourself. Smug-faced readers, managing editors, and big bosses don't like the true texts of women- female-sexed texts. That kind scares them. [21] For Cixous, ecriture feminine is not only a possibility for female writers; rather, she believes it can be (and has been) employed by male authors such as  James Joyce. Some have found this idea difficult to reconcile with Cixous’ definition of ecriture feminine (often termed ‘white ink’) because of the many references she makes to the female body (â€Å"There is always in her at least a little of that good mother’s milk. She writes in white ink†[22]) when characterizing the essence of ecriture feminine and explaining its origin. This notion raises problems for some theorists: â€Å"Ecriture feminine, then, is by its nature transgressive, rule-transcending, intoxicated, but it is clear that the notion as put forward by Cixous raises many problems. The realm of the body, for instance, is seen as somehow immune to social and gender condition and able to issue forth a pure essence of the feminine. Such essentialism is difficult to square with feminism which emphasizes femininity as a social construction†¦Ã¢â‚¬ [23] For Luce Irigaray, women's sexual pleasure  jouissance  cannot be expressed by the dominant, ordered, â€Å"logical,† masculine language because according to Kristeva, feminine language is derived from the pre-oedipal period of fusion between mother and child. Associated with the maternal, feminine language is not only a threat to culture, which is patriarchal, but also a medium through which women may be creative in new ways. Irigaray expressed this connection between women's sexuality and women's language through the following analogy: women's  jouissance  is more multiple than men's unitary, phallic pleasure because  [24] â€Å"woman has sex organs just about everywhere†¦ feminine language is more diffusive than its ‘masculine counterpart'. That is undoubtedly the reason†¦ her language†¦ goes off in all directions and†¦ e is unable to discern the coherence. †Ã‚  [25] Irigaray and Cixous also go on to emphasize that women, historically limited to being sexual objects for men (virgins or prostitutes, wives or mothers), have been prevented from expressing their sexuality in itself or for themselves. If they can do this, and if they can speak about it in the new languages it calls for, they will establ ish a point of view (a site of difference) from which phallogocentric concepts and controls can be seen through and taken apart, not only in theory, but also in practice. 26] ————————————————- [edit]Notes 1. ^  Baldick, Chris. Oxford Concise Dictionary of Literary Terms. OUP, 1990. 65. 2. ^  Showalter, Elaine. Critical Inquiry, Vol. 8, No. 2, Writing and Sexual Difference, (Winter, 1981), pp. 179-205. Published by: The University of Chicago Press. http://www. jstor. org/stable/1343159 3. ^  Irigaray, Luce,  Speculum of the Other Woman, Cornell University Press, 1985 4. ^  Cesbron, Georges, † Ecritures au feminin. Propositions de lecture pour quatre livres de femmes† in Degre Second, juillet 1980: 95-119 5.   Mistacco, Vicki, â€Å"Chantal Chawaf,† in Les femmes et la tradition litteraire – Anthologie du Moyen Age a nos jours; Seconde p artie: XIXe-XXIe siecles, Yale Press, 2006, 327-343 6. ^  Kristeva, Julia  Revolution in Poetic Language, Columbia University Press, 1984 7. ^  Griselda Pollock, â€Å"To Inscribe in the Feminine: A Kristevan Impossibility? Or Femininity, Melancholy and Sublimation. †Ã‚  Parallax, n. 8, [Vol. 4(3)], 1998. 81-117. 8. ^  Ettinger, Bracha,  Matrix . Halal(a) – Lapsus. Notes on Painting, 1985-1992. MOMA, Oxford, 1993. (ISBN 0-905836-81-2). Reprinted in:  Artworking 1985-1999. Edited by Piet Coessens. Ghent-Amsterdam: Ludion / Brussels: Palais des Beaux-Arts, 2000. (ISBN 90-5544-283-6) 9. ^  Ettinger, Bracha,  The Matrixial Borderspace  (essays 1994-1999), Minnesota University Press, 2006 10. ^  Pollock, Griselda, â€Å"Does Art Think? â€Å", in:  Art and Thought  Blackwell, 2003 11. ^  Ã¢â‚¬Å"Murfin, Ross C. †Ã‚  http://www. ux1. eiu. edu/~rlbeebe/what_is_feminist_criticism. pdf 12. ^  Moi, Toril, ed. French Feminist Thought. Basil Blac kwell Ltd, 1987. (ISBN 0-631-14972-4) 13.   Zajko, Vanda and Leonard, Miriam,  Laughing with Medusa. Oxford University Press, 2006 14. ^  a  b  Klages, Mary. â€Å"Helene Cixous: The Laugh of the Medusa. † 15. ^  Jones, Ann Rosalind. Feminist Studies, Vol. 7, No. 2 (Summer, 1981), pp. 247-263. Published by: Feminist Studies, Inc. http://www. jstor. org/stable/3177523 16. ^  Showalter, Elaine. â€Å"Feminist Criticism in the Wilderness. †Ã‚  The New Feminist Criticism: essays on women, literature, and theory. Elaine Showalter, ed. London: Virago, 1986. 249. 17. ^  Cixous, Helene. â€Å"The Laugh of the Medusa. †Ã‚  New French Feminisms. Elaine Marks and Isabelle de Courtivron, eds. New York: Schocken, 1981. 253. 18. ^  Barry, Peter. Beginning Theory  : An Introduction to Literary and Cultural Theory. New York: Manchester UP, 2002. 126 19. ^  Wayne A. Borody (1998) pp. 3, 5 Figuring the Phallogocentric Argument with Respect to the Classical Greek Philosophical Tradition Nebula: A Netzine of the Arts and Science, Vol. 13 (pp. 1-27) (http://kenstange. com/nebula/feat013/feat013. html) . 20. ^  a  b  Tong, Rosemarie Putnam. Feminist Thought  : A More Comprehensive Introduction. New York: Westview P, 2008. 276. 1. ^  Helene Cixous, Summer 1976. 22. ^  Klages, Mary. â€Å"Helene Cixous: ‘The Laugh of the Medusa. 23. ^  Barry, Peter. Beginning Theory  : An Introduction to Literary and Cultural Theory. New York: Manchester UP, 2002. 128. 24. ^  Murfin, Ross C. http://www. ux1. eiu. edu/~rlbeebe/what_is_feminist_criticism. pdf 25. ^  Irigaray, Luce. This Sex. 26. ^  Jones, Ann Rosalind. Fem inist Studies, Vol. 7, No. 2 (Summer, 1981), pp. 247-263. Published by: Feminist Studies, Inc. http://www. jstor. org/stable/3177523. ————————————————- [edit]External links

Case Study Hull North Ferriby – Describe the impact of the A63 (Ferriby by-pass) on North Ferriby

1. Describe the impact of the A63 (Ferriby by-pass) on North Ferriby. The A63 has made life easier for the residents of North Ferriby, noise and traffic has been significantly reduced as commuters travelling to Hull can use the by-pass instead of travelling on the B1231 through North Ferriby. The B1231 could become crowded if there was an accident or problem on the A63 as it could be closed meaning the B1231 would probably be used. 2. What is meant by the term satellite/commuter settlement? This is a village or town where the residents work in a nearby town or city. They live in the area and commute to work. The residents will be wealthy and own a car to drive to work. They consider living away from the city to be a better quality of life. 3. Describe the socio-economic groups that live in North Ferriby. Explain why they live in this location. The socio-economic groups are mainly skilled occupations, which are non-manual, managerial & technical. These are the groups with the highest percentages, 10% professional also live in the area. The people have a lot of money and can afford to live in the area, the houses are expensive and crime is low. 4. What is meant by the term â€Å"Counter Urbanisation†? You can read also Costco Case Study Counter urbanisation is the term used when people move away from the large cities towards the smaller towns and the countryside. 5. On a map of Hull mark on the â€Å"Rurban (Rural-Urban) Fringe†. 6. Using the deprivation map of Hull, how would you describe this area? To the south-east of the area the deprived area numbers are the greatest but as you look to the north-west the deprived area numbers fall and the map goes from dark to light meaning deprived to less deprived areas. The western side of Hull has the better quality of life; there are bigger houses and richer communities to be found there. As you move towards the east of Hull, the quality of life decreases and the houses become less respectable. Suburbia-Tranby 1. Describe the location in relation to Hull. Located 5 miles to the west of the city centre. 2. Describe the density and style of housing in the area. The houses are large sized detached or semi-detached with front and back gardens. They are quite far from the city centre so are very respectable, the density is low as the larger houses with gardens take up lots of space so there is a low density per km, this means that as you go from the city centre outwards the housing density will fall. 3. Describe the socio-economic structure of the area. The socio-economic groups are the highest towards the better end of the scale with few if any percentage of people at the bottom end of the scale. This shows that a lot of the people who live there will be rich and quite important people. 4. Describe the age structure of the people living there. The majority of the people living there are student age to middle age men and women. There are little people over 60 living there but there are older women living there. Hall Road – Inter War Housing 1.Describe the changes that have taken place in this environment. This area of Hull has recently undergone Envelope Action during the 1990's. The houses were improved one street at a time, which was cheaper, and the work was completed more quickly. Chimneys, windows, doors and roofs were all replaced, internal features were also improved and modernised with electricity and plumbing. Fences were erected and front gardens made. 2.How has the quality of life been improved? The standard of life was improved as each house was respectable and had its own land which helped neighbours socialise, also the house had hot water and electricity so were modernised and people could keep clean and warm. The houses wouldn't be damp any longer and drafts would also be reduced. The windows would do their job properly and keep the rain out. Orchard Park – Outer City Council Estate. 1.When was it built? It was built in the 1960's. 2.Why was it built? It was built to accommodate and improve the people in the area's quality of life. 3. Describe the style of residential accommodation. The housing was basic, with scarce space, had electricity and heated water supply. With all the heat and moisture inside and the thin walls separating the rooms from the outside, when it was cold outside and warm inside damp was caused inside the housing. 4. Describe the density and style of housing in the area. The density of housing in the area was very high, as many people would live in the high rise flats so the population would be very dense, also terraced housing would also be very dense as the houses were all joined together, and many all in one area. The houses were small so people would be almost packed into them adding to the density. The houses were scruffy looking and needed renovating. 5.To what extent were these an improvement to peoples ‘Quality of life'? The council basically gave people no choice in the matter and were forced to move into the high-rise flats. The houses were an improvement on their old housing but families were separated, people wasted money on transport into town and over the years the houses became damp and run down. This means that the residents quality of life wasn't really improved, they would probably have been happier overall if they had stayed in their old houses. 6.What groups of people live here? The socio economic groups are mainly unskilled and partly skilled workers. This shows that they will most probably be making little money and most probably have a basic education so the people would have a lot of difficulty trying to get a very well paid job. Princes Road 1.When was it built? Princes road was built in the 1900's. 2.What type of housing? The housing consists of terraced and low-rise flats. 3. Describe the Housing Tenure. The houses are mainly owner occupied, with either the occupier buying or owning the property, the houses which are rented are privately rented and not from the housing association or local authority. 4. Which groups of people live in the area? Give reasons why they may choose to live in this location. The majority of people are mainly 20 – 30 year old people both male and female. Great Thornton Street. Inner City Redevelopment 1. What changes took place during the 1960's? It has undergone â€Å"comprehensive redevelopment† during the late 1960's. 2. What style of residential accommodation was developed? The houses were improved if the actual structure of the house was sound. They would be fitted with new internal features such as hot water and indoor toilets. The houses were also made more respectable on the outside with new widows fitted and the walls painted, garden were also added which would improve the social environment as more people would talk and socialise. Chimneys, doors and roofs were all replaced, and fences erected also. 3. How did this improve the quality of life of people in the 1960's? Crime, burglary, car theft ; joy riding, prostitution and vandalism were reduced. The standard of life was improved as each house was respectable and had its own land which helped neighbours socialise, also the house had hot water and electricity so were modernised and people could keep clean and warm. The houses wouldn't be damp any longer and drafts would also be reduced. The windows would do their job properly and keep the rain out. 4. Between 1960 and 1980 this area began to experience problems. Describe these problems under the following headings: Built Environment. Social Environment. Economic Environment. Built Environment The houses and buildings began to become run down and worn out and were in a very bad state. Social Environment Families known as problem families made the area very rough and these families made crime, burglary, car theft & joy riding, prostitution and vandalism levels rise. These families were often moved on and the levels of violence etc would drastically reduce which solved the problems. Economic Environment The council would have had to pay for all the damage caused by the vandals and criminals, which would be a large amount of money as it will have all run up over time. Botanic Housing Action Area 1.When were the houses built? The houses were built in the 1900's and are mainly terraced. 2. What evidence can you find to see that this area has under gone â€Å"Envelope Action†? There are new chimneys, central heating, new doors, windows, window frames, brickwork has been uncluttered and more ‘defensible space', fences added, new plumbing and electric 3. How has this scheme improved the quality of life of people living in his area? Peoples quality of life have been greatly improved as their house would no longer be damp and cold, they would be dry and warm and would socialise more as the front gardens would help the social environment as it would bring neighbours closer together. Hot water and electric would drastically help their life quality as both are considered necessities. Hull Marina 1.Describe the changes to the economic environment during the late 1970's and early 1980's. During the 1970's de-industrialisation took place and the businesses in the area were closing down. The local council pumped money into the marina to improve the social environment and attract people, which would bring money into the marina area and Hull it self. 2. How did this affect the built environment? 3. How has the local partnership tackled this environment? 4. How has this area been improved? Gentrification 5.What type of residential accommodation is present? (Built environment). The residential accommodation that is present is cafà ¯Ã‚ ¿Ã‚ ½ bars, traditional pubs, shops and restaurants. 6.Which groups of people have moved into this area? The socio economic groups that have moved into the area are mainly people who are skilled at manual occupations and partly skilled people. Some are unskilled and a few of the people are managerial standard. The people who live here are generally middle-aged people or towards elderly. 7. How has the economy of the area been stimulated? Previously, when the fishermen were present in the area, the economy was quite low as they weren't earning a high wage and it was being spent in public houses and on essentials for the family. Now the people in the area earn a better wage and have better accommodation, which means they can spend their money on other things in the area such as the shops and restaurants. This means that the economy of the area has been stimulated by better industries and so forth, moving into the Hull Marina area.

Alibrandi Dairy Entry Essay Example for Free

Alibrandi Dairy Entry Essay I am writing for a number of reasons, As your father I feel really guilty for not being there for you and your mother for so long but If there is one message I would want you to hold in your heart always it is this you are loved unconditionally. that my love for you is not decided based on how you act, what you say or what happens on any given day. There are no conditions and the love is given freely to you Jose. I had never thought about what it would really feel like to have a child? To watch them grow and learn the ways of the world. I am often in awe at their wonder, their pure joy in the magic of life. But all at the same time I hurt when I see you Jose. But I know that you must experience life not just the small bits all of it, even the pain and the hurt it can bring. Although you and I have been in each others life for almost a year I want you to know, every day I see you becoming more and more yourself. I thank your mother for the hard work she has put into you because it must have been hard on her raising you own her own but I see that I have nothing to worry about because your Mother has raised an independent young woman, and I congratulate you on finishing your HSC and starting university, and I see the confident, strong individual I want to help you become. More than anything, that is my job as your father, to give you the guidance, support, freedom, and love to be who you are and who you want to be. It isn’t always easy, and I’m not always good at it. I get frustrated more than I wish I did. I yell more than I wish I did. When we butt heads, it is because I see my own insecurities reflected in yours like when you called me from school because you hit another girls nose with a book. Your mother and I want you to see the world stretched out before you, want you to see all the possibilities and potentialities and not be afraid of them, want to you be excited by your own abilities to shape your worlds, to change your futures, to make things right and better and beautiful. Jose if there is one thing I am thankful for it is you, Jose it hasn’t even been a year and yet and you have shown me what others long and search for many years, and that is love before I thought I had everything I had a great job, car and girlfriend but I always felt something was missing and you have shown me what I was missing. You are young and is still growing, and you are powerful. Know this, in your hearts, if nothing else. Even when you doubt it, or are scared or unsure, you are amazing, and you are never alone. Just as you are exploring and learning and making mistakes, so am I, as your father. But as your father, I am also doing all I can to make sure that you know that all of that is okay. And you, my Jose, my amazing Jose, are becoming who you are meant to be. I will help when I can, and get out of the way when I need to. But I will always, always be here, watching, amazed at who you are becoming. And if there is anything you need I am only a phone call away. Alibrandi Dairy Entry. (2017, May 21).

Many see globalization as an opportunity for international business, Essay

Many see globalization as an opportunity for international business, but it is claery a threat.Do you agreeExplain your answer with reference to the economic performance of so called BRIC countries - Essay Example Finally, the study will draw a conclusion based on these analyses. Globalisation is associated with economic growth, international business and financial market. It refers to a cross-border increase in free movement of services, products, labour and financial capital (Magazine, Inc., 2011). It is mainly driven by the flow of technology and ideas across the border. Globalisation can be examined from different perspectives such as economic, political and social perspectives. Also, globalisation is evaluated using four dimensions such as personal contract, political commitment, technological connectivity and economic arrangement (Beausang, 2012). Based on these globalisation perspectives different countries are ranked differently and score differently under various aspects. This implies that an individual country cannot score highly in all dimensions of globalisation. According to Leaders Magazine, Inc. (2011, p.68), â€Å"globalisation has a real impact, creating both opportunity and risk.† As countries’ economies expand in size and growth rate, they increase their relevance in the world economy demanding for robust political expression that matches their economic status. Despite the challenges of globalisation, many countries have benefited a great deal from engaging in trade relations with international nations. Globalisation is one the trends of the 21st century which is characterised by escalating web of connections between the developing and the developed countries of the globe steered by rapid transnational development (Chen & De Lombaerde, 2014). Technological advancements and declining transport and communication cost have intensified collaboration between international communities. Globalisation has influenced all aspects of human lives including social, political and economic aspects (European Union, 2012). The effects of globalisation on business are of more significance in this study. Various studies have established various

Digital and Visual Literacy Article Example | Topics and Well Written Essays - 1750 words

Digital and Visual Literacy - Article Example The secondary purpose is to indicate the lack of usage of the same to support the teaching part in the education system with digital literacy. The question that the authors are addressing is that what is it that defines literacy correctly in today's scenario, in a world where children are highly technology savvy. The question also addressed by the authors very precisely and lucidly is that what is the tool or manner which helps us have an ability to recognize whatever we witness, and infer correctly from what we experience. Yes the answer is digital as well as visual literacy. Unlike earlier times when overhead projector, handmade slides and chalk boards were used, these days, new media literacy technical skills are used in education like real time audio video interface, use of internet links for direct access, power point presentations, streaming videos etc. The authors have assumed their description of usage of digital tools in educational information to promote visual and digital literacy. This can be very well questioned as today educational institutions have are far more advanced than the view presented in the article. The reasoning of the authors supports the digital as well as visual literacy and its usage in today's competitive world and the reasoning is well supported by proofs which make a stronger case for better implications. 7. b. If we fail to take this line of reasoning seriously, the implications are: 30 If the authors' reasoning is not taken seriously, people would still

UNIT 3 INDIVIDUAL PROJECT Essay Example | Topics and Well Written Essays - 1250 words

UNIT 3 INDIVIDUAL PROJECT - Essay Example Preferably, all of the businesses exist for profit. Upon the conceptualization and realization of the said endeavor to put up an airline business, one must recognize the market, the competency, and the problems that are to be encountered in dealing with this kind of establishment. These illustrations points out to a certain airline which penetrate the skies and continues to soar high-the Virgin Atlantic Airlines. Wikipedia (2006), described this airline as â€Å"an airline belonging to Richard Bransons Virgin Group. It operates long-haul routes between London and North America, the Caribbean, Africa, the Middle East, Asia, and Australia. Its main bases are London Heathrow (LHR) and London Gatwick (LGW). Virgin has a smaller base at Manchester Airport (MAN) serving the USA and the Caribbean. The company holds a United Kingdom Civil Aviation Authority Type- A Operating Licence, which permits it to carry passengers, cargo, and mail on aircraft with 20 or more seats.†1 With the saturation of key markets around the globe, the airline has a promising future with regards to its navigation to the skies as well as it is regarded as one of the rising competitors of major airlines in the world. If we are to look into the history of this airline, it was set-up in 1982 by a lawyer and by the former chief pilot of the laker airline. During its beginnings, the co-owner of the airline has no thorough knowledge in running a business airliner and this prompted him to outsource and pirate employees in other airlines who has the expertise and knowledge in handling activities concerning airline operations. â€Å" One of the owners got the idea of putting up the enterprise from London to the Falkland Islands in June 1982, when the Falklands War ended and there was an apparent need for such a service†2 If we are to analyze this strategy, the owners have succeeded in heir preliminary strategy and that is to move where your market is. In such a case, the target

Lundy Marine nature reserve Essay Example | Topics and Well Written Essays - 750 words

Lundy Marine nature reserve - Essay Example In 1969 the divers discovered the existence of warm water marine species and the idea of a marine nature reserve came into being and was discussed. After this discussion, a stimulated interest in protecting the area grew and in 1971 Lundy Field Society proposed to establish a marine reserve. According to lundy.org.uk (1999) provision for the establishment of statutory Marine Nature Reserves was included in the 1981 Wildlife and Countryside Act. After public consultation, on 21st November 1986 the Secretary of State for Environment declared a statutory reserve at Lundy.The Management of Marine Nature Reserve was given to English Nature by â€Å"the statutory advisor to Government on nature conservation in England† (lundy.org.uk, 1999) i.e. the English Nature is responsible to look after the Marine Nature Reserve. Landmark Trust employed a Warden for funding who lease the island in association with the Devon Sea Fisheries Committee that regulates and manage fisheries in the area . Devon Sea Fisheries Committee and English Nature jointly proposed the first statutory No Take Zone which is a 3.3 square kilometre of sea on east side of the Lundy Marine Nature Reserve in the UK. According to this proposal of No Take Zone none of the marine life including lobsters, fish and crabs of the sea should be taken and if any one does he/she is punishable under Marine Life Act. The No Take Zone has received support from every quarter of life i.e. from local fishermen to Lundy management, Advisory Groups and Devon Sea Fisheries.

Corporate Social Responsibility Movement Essay Example | Topics and Well Written Essays - 2000 words

Corporate Social Responsibility Movement - Essay Example It is evidently clear from the discussion that the history of CSR in the UK had been a smooth one before the hurdles began making this one of the most difficult processes to undertake in the country. The aim was to provide a link between the corporate and the society, something that would see the regulation of activities within the required platforms. This would also see the growth of regulation based on the impact of transnational corporations that were setting base in the UK at the time. When the late nineteenth century saw a growing number of corporations in the world, the debate regarding the link between the corporations and the society became a debate that was in the public domain. The aim was to introduce new policies that would see most of these huge corporations share their profits with the society, or initiate new projects that would create and enhance regulation within the society. In the 1920s and 19230s, the main CSR strategies in place were trustee management that sough t to maximize wealth creation and growth of the community. From the 1930s to the 1970s, the corporate period was in motion and the UK companies took social responsibilities as the government did. The late 1970s saw the companies take up specific issues to handle, while the 1980s saw an increased responsiveness to community affairs. The 1990s and early millennium saw an increase in the CSR concepts as they became the base-point of completing other points of growth for the society as a whole. During the early twentieth century, companies were always working on meeting their demands while creating and enhancing new platforms that would see them prosper. However, this would imply redirecting their profits to other social causes as a means of meeting the key demands of the society. The main aim was to proceed with a new mentality that would see corporations in the UK grow further while still having the main ideas of the society in place. One problem that arose during the initial stages o f creating a strong CSR program at the time was the lack of a decisive definition of the term.

Definition of Acrson Essay Example | Topics and Well Written Essays - 1250 words

Definition of Acrson - Essay Example As per the statistics revealed by the public agencies, more than one hundred thousand incidents of the arsons were registered to the law enforcement agencies in different parts of United States. The religious hated have also attributed to the rise of the arson related cases, and there have been cases where the culprits have damaged the religious property for the sake of prevalence of the truth. The damage to the religious places and the justification of such heinous actions through misinterpretation of the religious teachings has been responsible for the clash between communities with different racial, religious and cultural customs. The arson is not responsible for the fatality of the life; rather it caused economic loss, which has to been accounted by the administration in efficient and effective manner. The arson is no longer a hidden crime; rather it is regarded as the 'murder by fire, a violent crime against property and people' (Nancy, 1997). According to reports, more than sev en hundred people are killed on annual basis due to the arson crime; the crime is responsible for causing damage to more than hundred thousand buildings, and cost loss of more than a billion dollar annually (Larry, 2006).According to Mr. Carrey Brown, U.S. Fire Administrator, 'there are, however, effective ways citizens, along with law enforcement and the fire service, can ensure the culprits are brought to justice' (Barry, 2004), thus the solution to the crimes associated with the arson can be rectified through proactive role and crucial efforts of the law enforcement agencies. The different forms taken by the Arson include, 'juvenile fire setting, vandalism, pyromania, a murder weapon, and concealment of a crime' (Barry, 2004), and the elimination of the problem is achievable through identification of the right faces of the arson. According to United States based national arson expert and chief of arson, Detroit Fire Department, Mr. Charles Evancho, 'Arson is one of the most diffi cult crimes to prosecute successfully. Often the criminal justice system does not view arson as a serious crime. The challenge is to develop sentencing for adults and juveniles' (Barry, 2004). The government agencies have launched several financial schemes which focus upon the financial provisions for the elimination of the arson. The United States government based agency provided '$2 million to 12 states to develop anti-arson programs' (Barry, 2004). The institutions have been established for the rehabilitation of the youth, with no parents and guardians. Recently 'USFA granted financial support a juvenile fire setter prevention program in partnership with a treatment center for abused children, the plan was implemented in Colorado. The intellectuals are of the opinion that public and private funding and participation is required to continue with such schemes, and it is important to realize that arson has to be controlled and handled 'several fronts and people must protect themselv es by strengthening prevention and apprehension efforts' (Barry, 2004). Arson is regarded as the 'second leading cause of residential fire deaths and accounts for approximately quarter of the fires incidents reported in the United States' (Barry, 2004), the crime shares one fifth of the damaged property in United States. According to reports, the crime claimed more than seven hundred lives on annual basis, and more than half a million fire incidents related to arson are reported. Only fifteen percent of the cases were able to reach conclusive stage where the arrests are made. It has It has been a common observation that the rate of arson is low in rural areas, whereas the in urban areas, the arson related incidents have reached alarming figure.

The police on Black Friday Essay Example for Free

The police on Black Friday Essay How far do sources 11 and 12 challenge the view presented in source 10 about the conduct of the police on Black Friday? Emily Davison was a woman who fought for womans suffrage in the late 1800s and early 1900s. She died on the 8th of June, 1913 after she ran in front of King George Vs horse Anmer at the Epsom Derby on 4 June 1913. Some people believe that this event caused a major breakthrough in later womens suffrage. Firstly, source 10, (The Times Newspaper) shows a rather negative view on Emily Davisons actions. For example, the newspaper instantly assumes that the desperate act of Davison was achieved only to spoil the race. The Times wrote this because they were a very right winged paper and did not completely support womens suffrage and gender equality. On the other hand, if the Davison was a man, the newspaper would not be so quick to assume that his actions were for a good cause and would probably be more sympathetic for his injuries. Within the same article Davison is described as an offender. This was most likely due to the fact that when this article was written, Davison had not yet died from her injuries. Therefore, The Times and the majority of its readers would not have much sympathy to her, but instead would see her as merely a nuisance. When compared, source 10 and 12 share a rather contrasting idea on the doings of Emily Davison considering both the articles are written by The Times. In source 10 Davison is described as desperate and as an offender. However, 10 days later (after the death of Davison), the tone of the newspaper completely changes, (source 12). Instead of being insulted and described negatively, Davisons actions are described as heroic. This change in view was purposely done due to the fact that Davison had recently died and many people saw her death as an important issue; The Times had to keep their readers happy and show sympathy for such a sacrifice. Source 11 pretty much displays a complete opposite view of Emily Davisons death compared to source 10. This is because Christabel Pankhurst was a fellow campaigner for womans suffrage in the Womens Social and Political  Union, (source 11 is an extract from Pankhursts autobiography, Unshackled). Pankhurst gives a much more positive and most likely biased view on the actions of Davison. For example, Pankhurst makes it seem as if Davison was the whole reason why women were seen as earnest for the vote. She also states that Davisons death brought the concentrated attention of millions to bear upon the cause. These two points were likely to be exaggerated as there was a good chance that Davison and Pankhurst were close because they both fought for the same cause. In contrast to source 11, source 10 states that Davisons deed is not likely to increase the popularity of any cause within the general public. This is pretty much the exact opposite of what Pankhurst was implying in her autobiography which makes it clear that source 11 and 10 both challenge one another highly with two slightly biased and altered stories of Emily Davisons protest. Overall, Emily Davisons death obviously had quite a large impact on womens suffrage within the UK as the vote was given to women in 1918 5 years after her death.

Digital Signal Processing (DSP) and CDMA Advantages

Digital Signal Processing (DSP) and CDMA Advantages INTRODUCTION ANALOG AND DIGITAL SIGNALS The signal is initially generated is in the form of an analog electrical voltage or current, produced for example by a microphone or some other type of transducer. The output from the readout system of a CD (compact disc) player, the data is already in digital form. An analog signal must be converted into digital form before DSP techniques can be applied. An analog electrical voltage signal, for example, can be digitized using an electronic circuit called an analog-to-digital converter or ADC. This generates a digital output as a stream of binary numbers whose values represent the electrical voltage input to the device at each sampling instant. Digital signal processing (DSP)-digital representation of signals and the use of digital processors to analyze, modify, or extract information from signals. Many signals in DSP are derived from analogue signals which have been sampled at regular intervals and converted into digital form. The key advantages of DSP over analogue processing are Guaranteed accuracy (determined by the number of bits used) Perfect reproducibility No drift in performance due to temperature or age Takes advantage of advances in semiconductor technology Greater flexibility (can be reprogrammed without modifying hardware) Superior performance (linear phase response possible, and filtering algorithms can be made adaptive) Sometimes information may already be in digital form. There are however (still) some disadvantages Speed and cost (DSP design and hardware may be expensive, especially with high bandwidth signals) Finite word length problems (limited number of bits may cause degradation). Application areas of DSP are considerable: Image processing (pattern recognition, robotic vision, image enhancement, facsimile, satellite weather map, animation) Instrumentation and control (spectrum analysis, position and rate control, noise reduction, data compression) Speech and audio (speech recognition, speech synthesis, text to speech, digital audio, equalisation) Military (secure communication, radar processing, sonar processing, missile guidance) Telecommunications (echo cancellation, adaptive equalisation, spread spectrum, video conferencing, data communication) Biomedical (patient monitoring, scanners, EEG brain mappers, ECG analysis, X-ray storage and enhancement). INTRODUCTION TO CDMA Code Division Multiple Access (CDMA) is a radically new concept in wireless communications. It has gained widespread international acceptance by cellular radio system operators as an upgrade that will dramatically increase both their system capacity and the service quality. It has likewise been chosen for deployment by the majority of the winners of the United States Personal Communications System spectrum auctions. It may seem, however, mysterious for those who arent familiar with it. CDMA is a form of spread-spectrum, a family of digital communication techniques that have been used in military applications for many years. The core principle of spread spectrum is the use of noise-like carrier waves, and, as the name implies, bandwidths much wider than that required for simple point-to-point communication at the same data rate. Originally there were two motivations: either to resist enemy efforts to jam the communications (anti-jam, or AJ), or to hide the fact that communication was even taking place, sometimes called low probability of intercept (LPI). It has a history that goes back to the early days of World War II. The use of CDMA for civilian mobile radio applications is novel. It was proposed theoretically in the late 1940s, but the practical application in the civilian marketplace did not take place until 40 years later. Commercial applications became possible because of two evolutionary developments. One was the availability of very low cost, high density digital integrated circuits, which reduce the size, weight, and cost of the subscriber stations to an acceptably low level. The other was the realization that optimal multiple access communication requires that all user stations regulate their transmitter powers to the lowest that will achieve adequate signal quality. CDMA changes the nature of the subscriber station from a predominately analog device to a predominately digital device. Old-fashioned radio receivers separate stations or channels by filtering in the frequency domain. CDMA receivers do not eliminate analog processing entirely, but they separate communication channels by means of a pseudorandom modulation that is applied and removed in the digital domain, not on the basis of frequency. Multiple users occupy the same frequency band. This universal frequency reuse is not fortuitous. On the contrary, it is crucial to the very high spectral efficiency that is the hallmark of CDMA. Other discussions in these pages show why this is true. CDMA is altering the face of cellular and PCS communication by: Dramatically improving the telephone traffic capacity Dramatically improving the voice quality and eliminating the audible effects of multipath fading Reducing the incidence of dropped calls due to handoff failures Providing reliable transport mechanism for data communications, such as facsimile and internet traffic Reducing the number of sites needed to support any given amount of traffic Simplifying site selection Reducing deployment and operating costs because fewer cell sites are needed Reducing average transmitted power Reducing interference to other electronic devices Reducing potential health risks Commercially introduced in 1995, CDMA quickly became one of the worlds fastest growing wireless technologies. In 1999, the International Telecommunications Union selected CDMA as the industry standard for new third-generation (3G) wireless systems. Many leading wireless carriers are now building or upgrading to 3G CDMA networks in order to provide more capacity for voice traffic, along with high-speed data capabilities. DS_CDMA Multiple access systems based on DS CDMA have achieved increasing significance for mobile communications applications. A promising concept is based on DS_CDMA applying MRC at the receiver. MRC takes advantage of the channel diversity to combat the multipath fading. However the capacity of a DS_CDMA system is limited by both multi-user interference and inter symbol interference ISI in high data rate applications. OFDM is applied to combat the frequency selectivity of the channel using a simple one tap equalizer Further more OFDM prevents the ISI and inter carrier interference ICI by inserting a guard interval between adjacent OFDM symbols OFDM is typically used for audio TV and HDTV transmission over terrestrial channels and achieves high spectral efficiency. The CMDA Technology overview FDMA In Frequency Division Multiple Access, the frequency band is divided in slots. Each user gets one frequency slot assigned that is used at will. It could be compared to AM or FM broadcasting radio where each station has a frequency assigned. FDMA demands good filtering. TDMA In Time Division Multiple Access, the frequency band is not partitioned but users are allowed to use it only in predefined intervals of time, one at a time. Thus, TDMA demands synchronization among the users. CDMA CDMA, for Code Division Multiple Access, is different from its traditional ways in which it does not allocate frequency or time in user slots but gives the right to use both to all users simultaneously. To do this, it uses a technique known as Spread Spectrum . In effect, each user is assigned a code,which spreads its signal bandwidth in such a way that only the same code can recover it at the receiver end. This method has the property that the unwanted signals with different codes get spread even more by the process, making them like noise to the receiver . Spread Spectrum Spread Spectrum is a mean of transmission where the data occupies a larger bandwidth than necessary. Bandwidth spreading is accomplished before the transmission through the use of a code, which is independent of the transmitted data. The same code is used to demodulate the data at the receiving end. The following figure illustrate the spreading done on the data signal x(t) by the spreading signal c(t) resulting in the message signal to be transmitted, m(t). Originally for military use to avoid jamming (interference created on purpose to make a communication channel unusable), spread spectrum modulation is now used in personal communication systems for its superior performance in an interference dominated environment . Definition of Spread Spectrum: A transmission technique in which a pseudo-noise code, independent of the information data, is employed as a modulation waveform to â€Å"spread† the signal energy over a bandwidth much greater than the signal information bandwidth. At the receiver the signal is â€Å"despread† using a synchronized replica of the pseudo-noise code. Basic Principle of Spread Spectrum System: The Principal types of Spread Spectrum are Direct Sequence (DS), and Frequency Hopping (FH). An over view of these systems is hereby given: Pseudo shift of the phase pseudo shift of the frequency Coherent demodulation noncoherent Direct Sequence Spread Spectrum (DSSS) A pseudo-noise sequence pnt generated at the modulator, is used in conjunction with an M-ary PSK modulation to shift the phase of the PSK signal pseudo randomly, at the chipping rate Rc (=1/Tc) a rate that is integer multiple of the symbol rate Rs (=1/Ts). The transmitted bandwidth is determined by the chip rate and by the base band filtering. The implementation limits the maximum chip rate Rc (clock rate) and thus the maximum spreading. The PSK modulation scheme requires a coherent demodulation. PN code length that is much longer than a data symbol, so that a different chip pattern is associated with each symbol. Frequency Hopping Spread Spectrum A Pseudo-noise sequence pnt generated at the modulator is used in conjuction with an M-ary FSK modulation to shift the carrier frequency of the FSK signal pseudurandomly, at the hopping rate Rh. The transmitted signal occupies a number of frequencies in time, each for a period of time Th (= 1/Rh), referred as dwell time. FHSS divides the available bandwidth into N channels and hops between these channels according to the PN sequence. At each frequency hop time the PN generator feeds the frequency synthesizer a frequency word FW (a sequence of n chips) which dictates one of 2n frequency position fhl . Transmitter and receiver follows the same frequency hop pattern. The transmitted bandwidth is determined by the lowest and highest hop position by the bandwidth per hop position (à ¢Ã‹â€ Ã¢â‚¬  fch). For a given hop, instantaneous occupied bandwidth is the conventional M-FSK, which is typically much smaller than Wss. So the FHSS signal is a narrowband signal, all transmission power is concentrated on one channel. Averaged over many hops, the FH/M-FSK spectrum occupies the entire spread spectrum bandwidth. Because the bandwidth of an FHSS system only depends on the tuning range, it can be hopped over a much wider bandwidth than an DSSS system. Since the hops generally result in phase discontinuity (depending on the particular implementation) a noncoherent demodulation is done at receiver. With slow hopping there are multiple data symbol per hop and with fast hopping there are multiple hops per data symbol. 3.3 Basic principle of Direct Sequence Spread Spectrum For BPSK modulation the building blocks of a DSSS system are: Input: Binary data dt with symbol rate Rs = 1/Ts (=bitrate Rb for BPSK) Pseudo-noise code pnt with chip rate Rc = 1/Tc (an integer of Rs) Spreading: In the transmitter, the binary data dt (for BPSK, I and Q for QPSK) is ‘directly multiplied with the PN sequence pnt , which is independent of the binary data, to produce the transmitted baseband signal txb: txb = dt . pnt The effect of multiplication of dt with a PN sequence is to spread the baseband bandwidth Rs of dt to a baseband bandwidth of Rc. Despreading: The spread spectrum signal cannot be detected by a conventional narrowband receiver. In the receiver, the baseband signal rxb is multiplied with the PN sequence pnr . If pnr = pnt and synchronized to the PN sequence in the received data, than the recovered binary data is produced on dr. The effect of multiplication of the spread spectrum signal rxb with the PN sequence pnt used in the transmitter is to despread the bandwidth of rxb to Rs . If pnr ≠  pnt , than there is no dispreading action. The signal dr has a spread spectrum. A receiver not knowing the PN sequence of the transmitter can not reproduce the transmitted data. Performance in the presence of interference: To simplify the presence of interference, the spread spectrum system is considered for baseband BPSK communication (without filtering). The received signal rxb of the transmitted signal txb plus an additive inteferance i (noise, other users, jammer,†¦Ã¢â‚¬ ¦): rxb = t xb + i = dt . pnt + i To recover the original data dt the received signal rx0 is multiplied with a locally generated PN sequence pnr that is an exact replica of that used in the transmitter (that is pnr = pnt and synchronized) The multiplier output is therefore given by: dr = rxb . pnt = dt . pnt . pnt + i . pnt The data signal dt is multiplied twice by the PN sequence pnt , where as the unwanted inteferance i is multiplied only once. Due to the property of the PN sequence: pnt + pnt = +1 for all t The multiplier output becomes: dr = dt + i . pnt The data signal dr is reproduced at the multiplier output in the receiver, except for the inteferance represented by the additive term i . pnt . Multiplication of the inteferance by the locally generated PN sequence, means that the spreading code will affect the inteferance just as it did with the information bearing signal at the transmitter. Noise and inteferance, being uncorrelated with the PN sequence, becomes noise-like, increase in bandwidth and decrease in power density after the multiplier. After dispreading, the data component dt is narrow band (Rb) whereas the inteferance component is wideband (Rc). By applying the dr signal to a baseband (low-pass) filter with a band width just large enough to accommodate the recovery of the data signal, most of the inteferance component i is filtered out. The effect of inteferance is reduced by processing gain (Gp). Narrowband inteferance: The narrowband noise is spread by the multiplication with the PN sequence pnr of the receiver. The power density of the noise is reduced with respect to the despread data signal. Only 1/Gp of the original noise power is left in the information baseband (Rs). Spreading and dispreading enables a bandwidth trade for processing gain against narrow band interfering signals. Narrow band inteferance would disable conventional narrow band receivers. The essence behind the inteferance rejection capability of a spread spectrum system: the useful signal (data) gets multiplied twice by the PN sequence, but the inteferance signal get multiplied only once. Wideband interference: Multiplication of the received signal with the PN sequence of the receiver gets a selective despread of the data signal (smaller bandwidth, higher power density). The inteferance signal is uncorrelated with the PN sequence and is spread. Origin of wideband noise: Multiple Spread Spectrum user: multiple access mechanism. Gaussian Noise: There is no increase in SNR with spread spectrum: The large channel bandwidth (Rc instead of Rs) increase the received noise power with Gp: Ninfo = N0 . BWinfo à   Nss = N0 . BWss = Ninfo .Gp The spread spectrum signal has a lower power density than the directly transmitted signal. Code division multiple access (CDMA) is a methode of multiplexing (wireless) users distinct (orthogonal) codes. All users can transmit at the same time, and each is allocated the entire available frequency spectrum for transmission. CDMA is also known as Spread-Spectrum multiple access (SSMA). CDMA dose not require the bandwidth allocation of FDMA, nor the time synchronization of the individual users needed in TDMA. A CDMA user has full time and full bandwidth available, but the quality of the communication decreases with an increasing number of users (BER ). In CDMA each user: Has its own PN code Uses the same RF bandwidth Transmits simultaneously (asynchronous or synchronous) Correlation of the received baseband spread spectrum signal rxb with the PN sequence of user 1 only despreads the signal of user 1. The other user produces noise Nu for user 1. ACCESS SCHEMES For radio systems there are two resources, frequency and time. Division by frequency, so that each pair of communicators is allocated part of the spectrum for all of the time, results in Frequency Division Multiple Access (FDMA). Division by time, so that each pair of communicators is allocated all (or at least a large part) of the spectrum for part of the time results in Time Division Multiple Access (TDMA). In Code Division Multiple Access (CDMA), every communicator will be allocated the entire spectrum all of the time. CDMA uses codes to identify connections. MULTIPATH AND RAKE RECEIVERS One of the main advantages of CDMA systems is the capability of using signals that arrive in the receivers with different time delays. This phenomenon is called multipath. FDMA and TDMA, which are narrow band systems, cannot discriminate between the multipath arrivals, and resort to equalization to mitigate the negative effects of multipath. Due to its wide bandwidth and rake receivers, CDMA uses the multipath signals and combines them to make an even stronger signal at the receivers. CDMA subscriber units use rake receivers. This is essentially a set of several receivers. One of the receivers (fingers) constantly searches for different multipaths and feeds the information to the other three fingers. Each finger then demodulates the signal corresponding to a strong multipath. The results are then combined together to make the signal stronger. Difference between TDMA vs CDMA. TDMA is Time Division Multiple Access, while CDMA is Code Division Multiple Access. Both technologies achieve the same goal of better utilization of the radio spectrum by allowing multiple users to share the same physical channel, but by using different methods and that is why the three of the four words in each acronym are identical. Both allow more than one person to carry out a conversation on the same frequency without causing interference. The two technologies differ in the way in which users share the common resource. In TDMA the channel is chopped up into sequential time slices. The data of each user is put on the channel in a round-robin fashion. In reality, only one user actually uses the channel at any given point of time, but he uses it only for short bursts. He then gives up the channel for a short duration to allow the other users to have their turn. This is similar to how a computer with just one processor runs multiple applications simultaneously. CDMA on the other hand allows everyone to transmit at the same time. With conventional methods of modulation techniques it would hav been simply not possible. What makes CDMA to allow all users to transmit simultaneously is a special type of digital modulation called Spread Spectrum. In this modulation technique users stream of bits is taken and splattered them across a very wide channel in a pseudo-random fashion. The pseudo part is very important here as at the receiver end the randomization must be undone in order to collect the bits together in a coherent order. For example consider a room full of couples, and each couple trying to carry on one-on-one conversations. In TDMA each couple takes their turn for talking and they keep their turns short by speaking only one sentence at a time. As there is always more one person speaking in the room at any given point of time, no one has to worry about being heard over the background din. In CDMA assume each couple talks simultaneously, but they all use different languages. The background din doesnt cause any real problem as none of the listeners understand any language other than that of the individual to whom they are listening. Voice Encoding At this point many people confuse two distinctly different issues involved in the transmission of digital audio. The first is the WAY in which the stream of bits is delivered from one end to the other. This part of the air interface is what makes one technology different from another. The second is the compression algorithm used to squeeze the audio into as small a stream of bits as possible. This latter component is known at the Voice Coder, or Vocoder for short. Another term commonly used is CODEC, which is a similar word to modem. It combines the terms COder and DECoder. Although each technology has chosen their own unique CODECs, there is no rule saying that one transmission method needs to use a specific CODEC. People often lump a technologys transmission method with its CODEC as though they were single entities. Voice encoding schemes differ slightly in their approach to the problem. Because of this, certain types of human voice work better with some CODECs than they do with others. The point to remember is that all PCS CODECs are compromises of some sort. Since human voices have such a fantastic range of pitch and tonal depth, one cannot expect any single compromise to handle each one equally well. This inability to cope with all types of voice at the same level does lead some people to choose one technology over another. All of the PCS technologies try to minimize battery consumption during calls by keeping the transmission of unnecessary data to a minimum. The phone decides whether or not you are presently speaking, or if the sound it hears is just background noise. If the phone determines that there is no intelligent data to transmit it blanks the audio and it reduces the transmitter duty cycle (in the case of TDMA) or the number of transmitted bits (in the case of CDMA). When the audio is blanked your caller would suddenly find themselves listening to dead air, and this may cause them to think the call has dropped. To avoid this psychological problem many service providers insert what is known as Comfort Noise during the blanked periods. Comfort Noise is synthesized white noise that tries to mimic the volume and structure of the real background noise. This fake background noise assures the caller that the connection is alive and well. However, in newer CODECs such as EVRC (used exclusively on CDMA systems) the background noise is generally suppressed even while the user is talking. This piece of magic makes it sound as though the cell phone user is not in a noisy environment at all. Under these conditions, Comfort Noise is neither necessary, nor desirable. DS-CDMA-INTRODUCTION While multiple access interference (MAI) by other users has been recognized as the capacity-limiting factor in direct sequence code-division multiple-access (DS-CDMA)-based cellular communication systems, multiuser approaches have largely alleviated the problem when the noise process is additive Gaussian. With the availability of multiuser detectors, inaccurate or inappropriate noise modelling assumptions seem to have become the issue again. Whereas multiuser detection has much to offer in the mobile- to-base station uplink, it does not at present appear to be feasible for the downlink due to the complexity involved and the lack of resistance against adjacent cell interference. Moreover, the few multiuser proposals for the downlink require the knowledge of all spreading codes, which is not possible in the tactical military environment, for instance. Enhanced single-user receivers equipped with adaptive filter banks deliver promising performance with reasonable complexity, especially in slowly varying channels. Thus, the performance of single-user detectors is still of interest, particularly in the presence of non-Gaussian noise. In both urban outdoor and indoor mobile radio environments, electromagnetic interference generated by man-made sources such as factories or power lines causes the noise to be of non-Gaussian nature. Large noise magnitudes are deemed very improbable by linear receivers, and consequently performance deterioration is experienced. It is therefore desirable to build systems that can maintain respectable functionality under a broad class of noise distributions, rather than strictly optimizing for the unrealistic Gaussian assumption. Such is the goal of robust detection and estimation theory, which aims to design systems that are suboptimal under nominal channel conditions (e.g., Gaussian channel) and yet do not face catastrophy when the noise distribution is not nominal (e.g., unlike linear schemes). Note that suboptimality here refers to very good performance that is slightly worse than that of the nominal-optimal detector/estimator. The direct sequence code division multiple access (DS-CDMA) technique has been favourably considered for application in digital mobile cellular networks due to its potential to provide higher system capacity over conventional multiple access techniques. Unlike FDMA and TDMA capacities which are mostly limited by the bandwidth, the capacity of a CDMA system is mainly restricted by its interference level. Any reduction in interference produces a direct and linear increase in system capacity. Multiple access interference (MAI) caused by non-zero cross-correlation between different spreading sequences is the major type of interference limiting the CDMA system capacity. Much work has been done to characterize MAI, and to analyze and evaluate the CDMA system performance in the presence of MAI. Since the cross-correlation properties of most sets of spreading codes are either too complex to analyze or very difficult to compute when different transmissions are not synchronized, a random seque nce model. In the case of moderate to large processing gains, Gaussian distribution with variable variance is a good approximation for the MAI distribution. One of the approaches to reduce MAI is to employ orthogonal spreading sequences, and try to synchronize the transmissions at the chip level (quasi-synchronization). However, this is generally difficult to achieve in multipoint-to-point systems, such as the reverse link (mobile-to-base) of a cellular system, due to a lack of synchronization of the various mobile terminals, and the variable transmission delays. In this paper, a multi-carrier DS-CDMA (MCDS-CDMA) scheme is employed to facilitate the synchronization process, and thus reduce MAI. SYSTEM MODEL A model of the MS-DS-CDMA system for the kth user of a CDMA system is shown in the figure 1. TRANMSITTER MODEL At the transmitter the user‘s data stream dk(t) is divided into M interleaved sub streams and spread by a spreading sequence ck(t) to a fraction 1/M of the entire transmission bandwidth W. The resultant chip sequences are then used to modulate M carrier. The carrier frequencies ωm,m=1,2,M are equally spaced by the chip rate so that they are mutually orthogonal over one channel symbol interval T. Let R be the information rate and Rc be the carrier control code rate then the channel symbol interval is BER PERFORMANCE: MC-DS-CDMA system performance measured by bit error rate through analysis and simulation. Analysis: The BER is analysed based on the following: Ortoganal spreading sequences with rectangular pulse shape are applied. ÃŽ ¶k,k=1†¦K are independent of random variables distributd in (-ÃŽ ¶D,ÃŽ ¶D) WHERE ÃŽ ¶D=ÃŽ µD+Ï‚D.Given W and ÃŽ ¶D,M is chosen so that ÃŽ ¶D It is assumed that the fading parameters of the desired user . It is perfectly estimated so that the coherent detection and optimum soft decision decoding could be carried out at the receiver to make the problem analytically tractable. The fading amplitudes as independent Rayleigh random variables with equal second moments. The model is MATLAB INTRODUCTION: Matlab is a commercial Matrix Laboratory package which operates as an interactive programming environment. It is a mainstay of the Mathematics Department software lineup and is also available for PCs and Macintoshes and may be found on the CIRCA VAXes. Matlab is well adapted to numerical experiments since the underlying algorithms for Matlabs builtin functions and supplied m-files are based on the standard libraries LINPACK and EISPACK. Matlab program and script files always have filenames ending with .m; the programming language is exceptionally straightforward since almost every data object is assumed to be an array. Graphical output is available to supplement numerical results. IMREAD Read image from graphics file. A = IMREAD(FILENAME,FMT) reads a grayscale or color image from the file specified by the string FILENAME. If the file is not in the current directory, or in a directory on the MATLAB path, specify the full pathname. The text string FMT specifies the format of the file by its standard file extension. For example, specify gif Digital Signal Processing (DSP) and CDMA Advantages Digital Signal Processing (DSP) and CDMA Advantages INTRODUCTION ANALOG AND DIGITAL SIGNALS The signal is initially generated is in the form of an analog electrical voltage or current, produced for example by a microphone or some other type of transducer. The output from the readout system of a CD (compact disc) player, the data is already in digital form. An analog signal must be converted into digital form before DSP techniques can be applied. An analog electrical voltage signal, for example, can be digitized using an electronic circuit called an analog-to-digital converter or ADC. This generates a digital output as a stream of binary numbers whose values represent the electrical voltage input to the device at each sampling instant. Digital signal processing (DSP)-digital representation of signals and the use of digital processors to analyze, modify, or extract information from signals. Many signals in DSP are derived from analogue signals which have been sampled at regular intervals and converted into digital form. The key advantages of DSP over analogue processing are Guaranteed accuracy (determined by the number of bits used) Perfect reproducibility No drift in performance due to temperature or age Takes advantage of advances in semiconductor technology Greater flexibility (can be reprogrammed without modifying hardware) Superior performance (linear phase response possible, and filtering algorithms can be made adaptive) Sometimes information may already be in digital form. There are however (still) some disadvantages Speed and cost (DSP design and hardware may be expensive, especially with high bandwidth signals) Finite word length problems (limited number of bits may cause degradation). Application areas of DSP are considerable: Image processing (pattern recognition, robotic vision, image enhancement, facsimile, satellite weather map, animation) Instrumentation and control (spectrum analysis, position and rate control, noise reduction, data compression) Speech and audio (speech recognition, speech synthesis, text to speech, digital audio, equalisation) Military (secure communication, radar processing, sonar processing, missile guidance) Telecommunications (echo cancellation, adaptive equalisation, spread spectrum, video conferencing, data communication) Biomedical (patient monitoring, scanners, EEG brain mappers, ECG analysis, X-ray storage and enhancement). INTRODUCTION TO CDMA Code Division Multiple Access (CDMA) is a radically new concept in wireless communications. It has gained widespread international acceptance by cellular radio system operators as an upgrade that will dramatically increase both their system capacity and the service quality. It has likewise been chosen for deployment by the majority of the winners of the United States Personal Communications System spectrum auctions. It may seem, however, mysterious for those who arent familiar with it. CDMA is a form of spread-spectrum, a family of digital communication techniques that have been used in military applications for many years. The core principle of spread spectrum is the use of noise-like carrier waves, and, as the name implies, bandwidths much wider than that required for simple point-to-point communication at the same data rate. Originally there were two motivations: either to resist enemy efforts to jam the communications (anti-jam, or AJ), or to hide the fact that communication was even taking place, sometimes called low probability of intercept (LPI). It has a history that goes back to the early days of World War II. The use of CDMA for civilian mobile radio applications is novel. It was proposed theoretically in the late 1940s, but the practical application in the civilian marketplace did not take place until 40 years later. Commercial applications became possible because of two evolutionary developments. One was the availability of very low cost, high density digital integrated circuits, which reduce the size, weight, and cost of the subscriber stations to an acceptably low level. The other was the realization that optimal multiple access communication requires that all user stations regulate their transmitter powers to the lowest that will achieve adequate signal quality. CDMA changes the nature of the subscriber station from a predominately analog device to a predominately digital device. Old-fashioned radio receivers separate stations or channels by filtering in the frequency domain. CDMA receivers do not eliminate analog processing entirely, but they separate communication channels by means of a pseudorandom modulation that is applied and removed in the digital domain, not on the basis of frequency. Multiple users occupy the same frequency band. This universal frequency reuse is not fortuitous. On the contrary, it is crucial to the very high spectral efficiency that is the hallmark of CDMA. Other discussions in these pages show why this is true. CDMA is altering the face of cellular and PCS communication by: Dramatically improving the telephone traffic capacity Dramatically improving the voice quality and eliminating the audible effects of multipath fading Reducing the incidence of dropped calls due to handoff failures Providing reliable transport mechanism for data communications, such as facsimile and internet traffic Reducing the number of sites needed to support any given amount of traffic Simplifying site selection Reducing deployment and operating costs because fewer cell sites are needed Reducing average transmitted power Reducing interference to other electronic devices Reducing potential health risks Commercially introduced in 1995, CDMA quickly became one of the worlds fastest growing wireless technologies. In 1999, the International Telecommunications Union selected CDMA as the industry standard for new third-generation (3G) wireless systems. Many leading wireless carriers are now building or upgrading to 3G CDMA networks in order to provide more capacity for voice traffic, along with high-speed data capabilities. DS_CDMA Multiple access systems based on DS CDMA have achieved increasing significance for mobile communications applications. A promising concept is based on DS_CDMA applying MRC at the receiver. MRC takes advantage of the channel diversity to combat the multipath fading. However the capacity of a DS_CDMA system is limited by both multi-user interference and inter symbol interference ISI in high data rate applications. OFDM is applied to combat the frequency selectivity of the channel using a simple one tap equalizer Further more OFDM prevents the ISI and inter carrier interference ICI by inserting a guard interval between adjacent OFDM symbols OFDM is typically used for audio TV and HDTV transmission over terrestrial channels and achieves high spectral efficiency. The CMDA Technology overview FDMA In Frequency Division Multiple Access, the frequency band is divided in slots. Each user gets one frequency slot assigned that is used at will. It could be compared to AM or FM broadcasting radio where each station has a frequency assigned. FDMA demands good filtering. TDMA In Time Division Multiple Access, the frequency band is not partitioned but users are allowed to use it only in predefined intervals of time, one at a time. Thus, TDMA demands synchronization among the users. CDMA CDMA, for Code Division Multiple Access, is different from its traditional ways in which it does not allocate frequency or time in user slots but gives the right to use both to all users simultaneously. To do this, it uses a technique known as Spread Spectrum . In effect, each user is assigned a code,which spreads its signal bandwidth in such a way that only the same code can recover it at the receiver end. This method has the property that the unwanted signals with different codes get spread even more by the process, making them like noise to the receiver . Spread Spectrum Spread Spectrum is a mean of transmission where the data occupies a larger bandwidth than necessary. Bandwidth spreading is accomplished before the transmission through the use of a code, which is independent of the transmitted data. The same code is used to demodulate the data at the receiving end. The following figure illustrate the spreading done on the data signal x(t) by the spreading signal c(t) resulting in the message signal to be transmitted, m(t). Originally for military use to avoid jamming (interference created on purpose to make a communication channel unusable), spread spectrum modulation is now used in personal communication systems for its superior performance in an interference dominated environment . Definition of Spread Spectrum: A transmission technique in which a pseudo-noise code, independent of the information data, is employed as a modulation waveform to â€Å"spread† the signal energy over a bandwidth much greater than the signal information bandwidth. At the receiver the signal is â€Å"despread† using a synchronized replica of the pseudo-noise code. Basic Principle of Spread Spectrum System: The Principal types of Spread Spectrum are Direct Sequence (DS), and Frequency Hopping (FH). An over view of these systems is hereby given: Pseudo shift of the phase pseudo shift of the frequency Coherent demodulation noncoherent Direct Sequence Spread Spectrum (DSSS) A pseudo-noise sequence pnt generated at the modulator, is used in conjunction with an M-ary PSK modulation to shift the phase of the PSK signal pseudo randomly, at the chipping rate Rc (=1/Tc) a rate that is integer multiple of the symbol rate Rs (=1/Ts). The transmitted bandwidth is determined by the chip rate and by the base band filtering. The implementation limits the maximum chip rate Rc (clock rate) and thus the maximum spreading. The PSK modulation scheme requires a coherent demodulation. PN code length that is much longer than a data symbol, so that a different chip pattern is associated with each symbol. Frequency Hopping Spread Spectrum A Pseudo-noise sequence pnt generated at the modulator is used in conjuction with an M-ary FSK modulation to shift the carrier frequency of the FSK signal pseudurandomly, at the hopping rate Rh. The transmitted signal occupies a number of frequencies in time, each for a period of time Th (= 1/Rh), referred as dwell time. FHSS divides the available bandwidth into N channels and hops between these channels according to the PN sequence. At each frequency hop time the PN generator feeds the frequency synthesizer a frequency word FW (a sequence of n chips) which dictates one of 2n frequency position fhl . Transmitter and receiver follows the same frequency hop pattern. The transmitted bandwidth is determined by the lowest and highest hop position by the bandwidth per hop position (à ¢Ã‹â€ Ã¢â‚¬  fch). For a given hop, instantaneous occupied bandwidth is the conventional M-FSK, which is typically much smaller than Wss. So the FHSS signal is a narrowband signal, all transmission power is concentrated on one channel. Averaged over many hops, the FH/M-FSK spectrum occupies the entire spread spectrum bandwidth. Because the bandwidth of an FHSS system only depends on the tuning range, it can be hopped over a much wider bandwidth than an DSSS system. Since the hops generally result in phase discontinuity (depending on the particular implementation) a noncoherent demodulation is done at receiver. With slow hopping there are multiple data symbol per hop and with fast hopping there are multiple hops per data symbol. 3.3 Basic principle of Direct Sequence Spread Spectrum For BPSK modulation the building blocks of a DSSS system are: Input: Binary data dt with symbol rate Rs = 1/Ts (=bitrate Rb for BPSK) Pseudo-noise code pnt with chip rate Rc = 1/Tc (an integer of Rs) Spreading: In the transmitter, the binary data dt (for BPSK, I and Q for QPSK) is ‘directly multiplied with the PN sequence pnt , which is independent of the binary data, to produce the transmitted baseband signal txb: txb = dt . pnt The effect of multiplication of dt with a PN sequence is to spread the baseband bandwidth Rs of dt to a baseband bandwidth of Rc. Despreading: The spread spectrum signal cannot be detected by a conventional narrowband receiver. In the receiver, the baseband signal rxb is multiplied with the PN sequence pnr . If pnr = pnt and synchronized to the PN sequence in the received data, than the recovered binary data is produced on dr. The effect of multiplication of the spread spectrum signal rxb with the PN sequence pnt used in the transmitter is to despread the bandwidth of rxb to Rs . If pnr ≠  pnt , than there is no dispreading action. The signal dr has a spread spectrum. A receiver not knowing the PN sequence of the transmitter can not reproduce the transmitted data. Performance in the presence of interference: To simplify the presence of interference, the spread spectrum system is considered for baseband BPSK communication (without filtering). The received signal rxb of the transmitted signal txb plus an additive inteferance i (noise, other users, jammer,†¦Ã¢â‚¬ ¦): rxb = t xb + i = dt . pnt + i To recover the original data dt the received signal rx0 is multiplied with a locally generated PN sequence pnr that is an exact replica of that used in the transmitter (that is pnr = pnt and synchronized) The multiplier output is therefore given by: dr = rxb . pnt = dt . pnt . pnt + i . pnt The data signal dt is multiplied twice by the PN sequence pnt , where as the unwanted inteferance i is multiplied only once. Due to the property of the PN sequence: pnt + pnt = +1 for all t The multiplier output becomes: dr = dt + i . pnt The data signal dr is reproduced at the multiplier output in the receiver, except for the inteferance represented by the additive term i . pnt . Multiplication of the inteferance by the locally generated PN sequence, means that the spreading code will affect the inteferance just as it did with the information bearing signal at the transmitter. Noise and inteferance, being uncorrelated with the PN sequence, becomes noise-like, increase in bandwidth and decrease in power density after the multiplier. After dispreading, the data component dt is narrow band (Rb) whereas the inteferance component is wideband (Rc). By applying the dr signal to a baseband (low-pass) filter with a band width just large enough to accommodate the recovery of the data signal, most of the inteferance component i is filtered out. The effect of inteferance is reduced by processing gain (Gp). Narrowband inteferance: The narrowband noise is spread by the multiplication with the PN sequence pnr of the receiver. The power density of the noise is reduced with respect to the despread data signal. Only 1/Gp of the original noise power is left in the information baseband (Rs). Spreading and dispreading enables a bandwidth trade for processing gain against narrow band interfering signals. Narrow band inteferance would disable conventional narrow band receivers. The essence behind the inteferance rejection capability of a spread spectrum system: the useful signal (data) gets multiplied twice by the PN sequence, but the inteferance signal get multiplied only once. Wideband interference: Multiplication of the received signal with the PN sequence of the receiver gets a selective despread of the data signal (smaller bandwidth, higher power density). The inteferance signal is uncorrelated with the PN sequence and is spread. Origin of wideband noise: Multiple Spread Spectrum user: multiple access mechanism. Gaussian Noise: There is no increase in SNR with spread spectrum: The large channel bandwidth (Rc instead of Rs) increase the received noise power with Gp: Ninfo = N0 . BWinfo à   Nss = N0 . BWss = Ninfo .Gp The spread spectrum signal has a lower power density than the directly transmitted signal. Code division multiple access (CDMA) is a methode of multiplexing (wireless) users distinct (orthogonal) codes. All users can transmit at the same time, and each is allocated the entire available frequency spectrum for transmission. CDMA is also known as Spread-Spectrum multiple access (SSMA). CDMA dose not require the bandwidth allocation of FDMA, nor the time synchronization of the individual users needed in TDMA. A CDMA user has full time and full bandwidth available, but the quality of the communication decreases with an increasing number of users (BER ). In CDMA each user: Has its own PN code Uses the same RF bandwidth Transmits simultaneously (asynchronous or synchronous) Correlation of the received baseband spread spectrum signal rxb with the PN sequence of user 1 only despreads the signal of user 1. The other user produces noise Nu for user 1. ACCESS SCHEMES For radio systems there are two resources, frequency and time. Division by frequency, so that each pair of communicators is allocated part of the spectrum for all of the time, results in Frequency Division Multiple Access (FDMA). Division by time, so that each pair of communicators is allocated all (or at least a large part) of the spectrum for part of the time results in Time Division Multiple Access (TDMA). In Code Division Multiple Access (CDMA), every communicator will be allocated the entire spectrum all of the time. CDMA uses codes to identify connections. MULTIPATH AND RAKE RECEIVERS One of the main advantages of CDMA systems is the capability of using signals that arrive in the receivers with different time delays. This phenomenon is called multipath. FDMA and TDMA, which are narrow band systems, cannot discriminate between the multipath arrivals, and resort to equalization to mitigate the negative effects of multipath. Due to its wide bandwidth and rake receivers, CDMA uses the multipath signals and combines them to make an even stronger signal at the receivers. CDMA subscriber units use rake receivers. This is essentially a set of several receivers. One of the receivers (fingers) constantly searches for different multipaths and feeds the information to the other three fingers. Each finger then demodulates the signal corresponding to a strong multipath. The results are then combined together to make the signal stronger. Difference between TDMA vs CDMA. TDMA is Time Division Multiple Access, while CDMA is Code Division Multiple Access. Both technologies achieve the same goal of better utilization of the radio spectrum by allowing multiple users to share the same physical channel, but by using different methods and that is why the three of the four words in each acronym are identical. Both allow more than one person to carry out a conversation on the same frequency without causing interference. The two technologies differ in the way in which users share the common resource. In TDMA the channel is chopped up into sequential time slices. The data of each user is put on the channel in a round-robin fashion. In reality, only one user actually uses the channel at any given point of time, but he uses it only for short bursts. He then gives up the channel for a short duration to allow the other users to have their turn. This is similar to how a computer with just one processor runs multiple applications simultaneously. CDMA on the other hand allows everyone to transmit at the same time. With conventional methods of modulation techniques it would hav been simply not possible. What makes CDMA to allow all users to transmit simultaneously is a special type of digital modulation called Spread Spectrum. In this modulation technique users stream of bits is taken and splattered them across a very wide channel in a pseudo-random fashion. The pseudo part is very important here as at the receiver end the randomization must be undone in order to collect the bits together in a coherent order. For example consider a room full of couples, and each couple trying to carry on one-on-one conversations. In TDMA each couple takes their turn for talking and they keep their turns short by speaking only one sentence at a time. As there is always more one person speaking in the room at any given point of time, no one has to worry about being heard over the background din. In CDMA assume each couple talks simultaneously, but they all use different languages. The background din doesnt cause any real problem as none of the listeners understand any language other than that of the individual to whom they are listening. Voice Encoding At this point many people confuse two distinctly different issues involved in the transmission of digital audio. The first is the WAY in which the stream of bits is delivered from one end to the other. This part of the air interface is what makes one technology different from another. The second is the compression algorithm used to squeeze the audio into as small a stream of bits as possible. This latter component is known at the Voice Coder, or Vocoder for short. Another term commonly used is CODEC, which is a similar word to modem. It combines the terms COder and DECoder. Although each technology has chosen their own unique CODECs, there is no rule saying that one transmission method needs to use a specific CODEC. People often lump a technologys transmission method with its CODEC as though they were single entities. Voice encoding schemes differ slightly in their approach to the problem. Because of this, certain types of human voice work better with some CODECs than they do with others. The point to remember is that all PCS CODECs are compromises of some sort. Since human voices have such a fantastic range of pitch and tonal depth, one cannot expect any single compromise to handle each one equally well. This inability to cope with all types of voice at the same level does lead some people to choose one technology over another. All of the PCS technologies try to minimize battery consumption during calls by keeping the transmission of unnecessary data to a minimum. The phone decides whether or not you are presently speaking, or if the sound it hears is just background noise. If the phone determines that there is no intelligent data to transmit it blanks the audio and it reduces the transmitter duty cycle (in the case of TDMA) or the number of transmitted bits (in the case of CDMA). When the audio is blanked your caller would suddenly find themselves listening to dead air, and this may cause them to think the call has dropped. To avoid this psychological problem many service providers insert what is known as Comfort Noise during the blanked periods. Comfort Noise is synthesized white noise that tries to mimic the volume and structure of the real background noise. This fake background noise assures the caller that the connection is alive and well. However, in newer CODECs such as EVRC (used exclusively on CDMA systems) the background noise is generally suppressed even while the user is talking. This piece of magic makes it sound as though the cell phone user is not in a noisy environment at all. Under these conditions, Comfort Noise is neither necessary, nor desirable. DS-CDMA-INTRODUCTION While multiple access interference (MAI) by other users has been recognized as the capacity-limiting factor in direct sequence code-division multiple-access (DS-CDMA)-based cellular communication systems, multiuser approaches have largely alleviated the problem when the noise process is additive Gaussian. With the availability of multiuser detectors, inaccurate or inappropriate noise modelling assumptions seem to have become the issue again. Whereas multiuser detection has much to offer in the mobile- to-base station uplink, it does not at present appear to be feasible for the downlink due to the complexity involved and the lack of resistance against adjacent cell interference. Moreover, the few multiuser proposals for the downlink require the knowledge of all spreading codes, which is not possible in the tactical military environment, for instance. Enhanced single-user receivers equipped with adaptive filter banks deliver promising performance with reasonable complexity, especially in slowly varying channels. Thus, the performance of single-user detectors is still of interest, particularly in the presence of non-Gaussian noise. In both urban outdoor and indoor mobile radio environments, electromagnetic interference generated by man-made sources such as factories or power lines causes the noise to be of non-Gaussian nature. Large noise magnitudes are deemed very improbable by linear receivers, and consequently performance deterioration is experienced. It is therefore desirable to build systems that can maintain respectable functionality under a broad class of noise distributions, rather than strictly optimizing for the unrealistic Gaussian assumption. Such is the goal of robust detection and estimation theory, which aims to design systems that are suboptimal under nominal channel conditions (e.g., Gaussian channel) and yet do not face catastrophy when the noise distribution is not nominal (e.g., unlike linear schemes). Note that suboptimality here refers to very good performance that is slightly worse than that of the nominal-optimal detector/estimator. The direct sequence code division multiple access (DS-CDMA) technique has been favourably considered for application in digital mobile cellular networks due to its potential to provide higher system capacity over conventional multiple access techniques. Unlike FDMA and TDMA capacities which are mostly limited by the bandwidth, the capacity of a CDMA system is mainly restricted by its interference level. Any reduction in interference produces a direct and linear increase in system capacity. Multiple access interference (MAI) caused by non-zero cross-correlation between different spreading sequences is the major type of interference limiting the CDMA system capacity. Much work has been done to characterize MAI, and to analyze and evaluate the CDMA system performance in the presence of MAI. Since the cross-correlation properties of most sets of spreading codes are either too complex to analyze or very difficult to compute when different transmissions are not synchronized, a random seque nce model. In the case of moderate to large processing gains, Gaussian distribution with variable variance is a good approximation for the MAI distribution. One of the approaches to reduce MAI is to employ orthogonal spreading sequences, and try to synchronize the transmissions at the chip level (quasi-synchronization). However, this is generally difficult to achieve in multipoint-to-point systems, such as the reverse link (mobile-to-base) of a cellular system, due to a lack of synchronization of the various mobile terminals, and the variable transmission delays. In this paper, a multi-carrier DS-CDMA (MCDS-CDMA) scheme is employed to facilitate the synchronization process, and thus reduce MAI. SYSTEM MODEL A model of the MS-DS-CDMA system for the kth user of a CDMA system is shown in the figure 1. TRANMSITTER MODEL At the transmitter the user‘s data stream dk(t) is divided into M interleaved sub streams and spread by a spreading sequence ck(t) to a fraction 1/M of the entire transmission bandwidth W. The resultant chip sequences are then used to modulate M carrier. The carrier frequencies ωm,m=1,2,M are equally spaced by the chip rate so that they are mutually orthogonal over one channel symbol interval T. Let R be the information rate and Rc be the carrier control code rate then the channel symbol interval is BER PERFORMANCE: MC-DS-CDMA system performance measured by bit error rate through analysis and simulation. Analysis: The BER is analysed based on the following: Ortoganal spreading sequences with rectangular pulse shape are applied. ÃŽ ¶k,k=1†¦K are independent of random variables distributd in (-ÃŽ ¶D,ÃŽ ¶D) WHERE ÃŽ ¶D=ÃŽ µD+Ï‚D.Given W and ÃŽ ¶D,M is chosen so that ÃŽ ¶D It is assumed that the fading parameters of the desired user . It is perfectly estimated so that the coherent detection and optimum soft decision decoding could be carried out at the receiver to make the problem analytically tractable. The fading amplitudes as independent Rayleigh random variables with equal second moments. The model is MATLAB INTRODUCTION: Matlab is a commercial Matrix Laboratory package which operates as an interactive programming environment. It is a mainstay of the Mathematics Department software lineup and is also available for PCs and Macintoshes and may be found on the CIRCA VAXes. Matlab is well adapted to numerical experiments since the underlying algorithms for Matlabs builtin functions and supplied m-files are based on the standard libraries LINPACK and EISPACK. Matlab program and script files always have filenames ending with .m; the programming language is exceptionally straightforward since almost every data object is assumed to be an array. Graphical output is available to supplement numerical results. IMREAD Read image from graphics file. A = IMREAD(FILENAME,FMT) reads a grayscale or color image from the file specified by the string FILENAME. If the file is not in the current directory, or in a directory on the MATLAB path, specify the full pathname. The text string FMT specifies the format of the file by its standard file extension. For example, specify gif