第一篇：英語中英文翻譯

英語中英文翻譯

第一篇：

對龍圖騰的崇拜在中國大約已綿延了八千多年。中國龍是古人將魚、蛇、馬、牛等動物與云霧、雷電等自然天象集合而成的一種神物。中國龍的形成與中華民族的多元融合過程同步。在中國人的心目中，龍具有振奮騰飛、開拓變化的寓意和團結凝聚的精神。

Dragon totem worship in China has been around for the last 8,000 years.The ancients in China considered the dragon a fetish that combines animals including the fish, snake, horse and ox with cloud, thunder, lightning and other natural celestial phenomena.The Chinese dragon was formed in accordance with the multicultural fusion process of the Chinese nation.To the Chinese, the dragon signifies initiative,innovation and cohesion.第二篇：

長城是人類創造的世界奇跡之一。如果你到了中國卻沒去過長城，就像到了巴黎沒有去看看埃菲爾鐵塔，或者就像到了埃及沒有去看金字塔一樣。人們常說：“不到長城非好漢。”實際上，長城最初只是一些斷斷續續的城墻，直到秦朝統一中國后才將其連成長城。然而，今天我們看到的長城——東起山海關，西至嘉峪關——大部分都是在明代修建的。

The Great Wall is one of the wonders of the world that was created by human beings!If you come to China without climbing the Great Wall, it?s just like going to Paris without visiting the Eiffel Tower, or going to Egypt without visiting the Pyramids!Men often say, “He who does not reach the Great Wall is not a true man.” In fact, it began as independent walls for different states when it was first built, and did not become the “Great Wall” until the Qin Dynasty when the emperor united China.However, the wall we see today, starting from Shanhaiguan Pass in the east to Jiayuguan Pass in the west, was mostly built during the Ming Dynasty.第三篇：

餃子Dumplings ravioli 是深受中國人民喜愛的傳統食品。相傳為古代醫圣張仲景發明。餃子的制作是包括： 1）搟皮、2）備餡、3）包餡水煮三個步驟。其特點是皮薄餡嫩，味道鮮美，形狀獨特，百食不厭。民間有“好吃不過餃子”的俗語。中國人接親待客、逢年過節都有包餃子吃的習俗，寓意吉利。對崇尚親情的中國人來說，“更歲交子”吃餃子，更是歡度除夕、辭舊迎新必不可少的內容。

Dumplings are one of the Chinese people?s favorite traditional dishes.According to an ancient Chinese legend, dumplings were first made by the medical saint---Zhang Zhongjing.There are three steps involved in making dumplings: 1)make dumpling wrappers out of dumpling flour;2)prepare the dumpling stuffing;3)make dumplings and boil them.With thin and elastic dough skin, fresh and tender stuffing, delicious

taste, and unique shapes, dumplings are worth eating hundreds of times.There?s an old saying that claims, “Nothing could be more delicious than dumplings”.During the Spring Festival and other holidays, or when treating relatives and friends, Chinese people like to follow the auspicious custom of eating dumplings.To Chinese people who show high reverence for family love, having dumplings at the moment the old year is replaced by the new is an essential part of bidding farewell to the old and ushering in the new year.第四篇：

聞名于世的絲綢之路是一系列連接東西方的路線。絲綢之路延伸6,000多公里。得名于古代中國的絲綢貿易。絲綢之路上的貿易在中國、南亞、歐洲和中東文明發展中發揮了重要作用。正是通過絲綢之路，中國的造紙、火藥、指南針、印刷等四大發明才被引介到世界各地。同樣，中國的絲綢、茶葉和瓷器（porcelain）也傳遍全球。物質文化的交流是雙向的。歐洲也通過絲綢之路出口各種商品和植物，滿足中國市場的需要。

The world-renowned Silk Road is a series of routes connecting the East and the West.It extended more than 6,000 kilometers.The Silk Road was named after ancient China?s silk trade which played an important role in the civilization development of China, South Asia, Europe and the Middle East.It was through the Silk Road that papermaking, gunpowder, compass and printing of the four great inventions of ancient China were introduced around the world.Similarly, Chinese silk, tea and porcelain spread all over the world.Europe also exported various goods and plants through the Silk Road to meet the needs of the Chinese market.第五篇：

中國園林是經過三千多年演化而成的獨具一格的園林景觀。它既包括為皇室成員享樂而建造的大型花園，也包括學者、商人和卸任的政府官員為擺脫嘈雜的外部世界而建造的私家花園。這些花園構成了一種意在表達人與自然之間應有的調和關系的微縮景觀。典型的中國園林周圍有圍墻，園內有池塘、假山、樹木、花草以及各種各樣由彎曲的小路和走廊銜接的建筑。散步在花園中，人們可以看到一系列精心設計的景觀猶如山水畫卷一般展示在面前。

Chinese gardens came into being after three thousand years of evolution and unique landscape.It includes both large garden built for the royal family enjoyment, including academics, businessmen, and former government officials to get rid of the noise of the outside world and build private garden.These gardens constituted an intended to express the human and the nature should be harmonious relations between miniature landscape.A typical Chinese garden surrounded by a fence, garden with ponds, rockeries, trees, flowers and plants, and various buildings connected by winding paths and corridors.Stroll in the garden, people can see a series of carefully designed like landscape picture show in front of the landscape.第六篇：

中國人自古以來就在中秋時節慶祝豐收，這與北美地區慶祝感恩節的習俗十分相似，過中秋節的習俗與唐代早期在中國各地開始流行，中秋節在農歷八月十五，是人們拜月的節日，這天夜晚皓月當空，人們合家團聚，共賞明月。2006年，中秋節被列為中國的文化遺產，2008年又被定為公共假日，月餅被視為中秋節不可或缺的美食，人們將月餅作為禮物饋贈親友或在家庭聚會上享用。傳統的月餅上帶有“壽”(longevity)、“福”或“和”等字樣。

Since ancient times, the Chinese people usually celebrate harvest in the Mid-Autumn, which is similar to the custom of celebrating Thanksgiving in the North America.The tradition of celebrating Mid-Autumn festival became popular throughout China in the early Tang dynasty.The lunar August 15 is a day for people worshiping the moon.On this day, under the dazzling bright moon, families reunite and enjoy the moon?s beauty.In 2006, Mid-Autumn festival was listed as one of China's cultural heritage, and in 2008, it was classified as a public holiday.Moon cakes, as indispensable delicious food of the festival, were gifts people sent to families and friends during the festival and usually eaten on family gatherings.There are characters of “longevity”，“good fortune”and “harmony” on the Traditional moon cakes.

第二篇：英語短文中英文翻譯

1.Today my friend and I are taking a walk.suddenly, we are seeing a boy sit on the chair,he is crying,we go and ask him.“what’s the matter with you” he tell us“I can’t find my dog can you help me”.“yes,I can”.And we help him find his dong.oh it stay under the big tree!今天我和我的朋友一起去散步。突然我們看見一個男孩坐在椅子上，他哭的很傷心。我們走過去問他：“你怎么了”。他告訴我們：“我的狗不見了，你們能幫我找到它嗎”。“是的，我們能幫你找到你的狗”然后我們幫助他找到了他的狗，原來是它呆在一棵大樹下。2.One day an old man siselling a big elephant.A young man comes to the elephant and begins to look at it slowly.The old man goes up to him and says inhis ear,“Don't say anything about the elephant before I sell it,then i'll give you some money.”“All right,”says the young man.After the old man slles the elephant,he gives the young man some money and says,“Now,can you tell me how you find the bad ears of theelephant?”“I don't find the bad ears,”says the young man.“Then why do you look at the elephant slowly?”asks the old man.The young man answers,“Because I never see an elephant before,and I want to know what it looks like.”

一天，一個老的男人正在賣一頭大象。一個年輕的男人走向大象然后開始慢慢看著它（大象），這個老的男人走向他對著他的耳朵說，“不要在我賣出它（大象）之前說關于它（大象）的事，然后我會給你一些錢。”“好的”，這個年輕的男人說。在這個老的男人賣出大象后，他給了年輕的男人一些錢并且說，“現在，你可以告訴我你是怎樣知道大象的壞的耳朵了吧？”“我不知道壞的耳朵”，這個年輕的男人說。“然后為什么你慢慢的看著大象？”這個老的男人問。這個年輕的男人回答，“因為我在這之前從來沒有見過大象，還有我想知道它（大象）是什么樣子的。”

3.An old woman had a cat.The cat was very old;she could not run quickly, and she could not bite, because she was so old.One day the old cat saw a mouse;she jumped and caught the mouse.But she could not bite it;so the mouse got out of her mouth and ran away, because the cat could not bite it.Then the old woman became very angry because the cat had not killed the mouse.She began to hit the cat.The cat said, “Do not hit your old servant.I have worked for you for many years, and I would work for you still, but I am too old.Do not be unkind to the old, but remember what good work the old did when they were young.” 一位老婦有只貓，這只貓很老，它跑不快了，也咬不了東西，因為它年紀太大了。一天，老貓發現一只老鼠，它跳過去抓這只老鼠，然而，它咬不住這只老鼠。因此，老鼠從它的嘴邊溜掉了，因為老貓咬不了它。

于是，老婦很生氣，因為老貓沒有把老鼠咬死。她開始打這只貓，貓說：“不要打你的老仆人，我已經為你服務了很多年，而且還愿意為你效勞，但是，我實在太老了，對年紀大的不要這么無情，要記住老年人在年青時所做過的有益的事情。”

4.I love my family, because I have a happy family.My father is an English teacher.His name is Jacky.He is thirty-eight.He likes playing basketball.What’s my mother job? Is she a teacher? Yes, you’re right!My mother is very kind and nice, she is thirty-seven.My mother is always laborious work.I love my parents!On Saturday and Sunday, I often go to the library and play the piano, My father go to play basketball.Sometimes, we watch TV and listen to music at home.I love my family.Because I’m very happy to live with my parents together!我愛我的家庭,因為我有一個快樂的家庭.我的爸爸是一名英語教師,他的名字叫Jacky.他今年38歲.他非常喜歡打籃球.我的媽媽是趕什么呢?她是一名教師嗎?是的.你說對了!我的媽媽是一個很親切、友善的人,她今年37歲.我媽媽總是勤勞的干活.我愛我的父母.在星期六和星期天里,我經常去圖書館和彈鋼琴.我爸爸去打籃球.有時侯,我們都在家看電視和聽音樂.我愛我家.因為我和爸爸媽媽一起生活得很開心!4.This is my room.Near the window there is a desk.I often do my homework at it.You can see some books, some flowers in a vase, a ruler and a pen.On the wall near the desk there is a picture of a cat.There is a clock above the end of my bed.I usually put my shoe under my bed.Of course there is a chair in front of the desk.I sit there and I can see the trees and roads outside.這是我的房間。在窗口附近有一張書桌。我經常在那做我的家庭作業。您能看有些書，有些花在花瓶里，一把格尺和筆。在墻壁在書桌有貓的圖片。有一個時鐘在我的床上的末端。我通常把我的鞋子放在我的床下。當然有一把椅子在書桌前面。我坐那里，并且我能看外面的樹和路

6.What do you know about the sea? Some people know about it, but others don’t.The sea looks beautiful on a fine sunny day, the sea is very big.In the world, there is more sea than land.Do you know Hainan Island? It’s really very nice.We can see beaches, trees and the sea.We can swim and visit a lot of beautiful places.海

你對海知道些什么？ 某些人知道關于它，但其他不。海看起來美麗在一個美好的晴天，海是非常大的。在世界上，比土地有更多海。您是否知道海南島？ 那非常好。我們能看海灘、樹和海。我們可以游泳和參觀很多美好的地方。

7.Computers are changing our life.You can do a lot of things with a computer.Such as, you can use a computer to write articles, watch video CDs, play games and do office work.But the most important use of a computer is to join the Internet.We don’t need to leave home to borrow books from a library or to do shopping in a supermarket.Computers help us live a more convenient life.計算機改變我們的生活。您能做很多事用計算機。例如，您能使用計算機寫文章，手表錄影CDs，戲劇比賽和完成辦公室工作。但對計算機的最重要的用途是加入Internet.我們不需要離開家去從圖書館借用書或在超級市場做購物。計算機幫助我們居住更加方便的生活。

8.Summer is the great season for all sports in the open air.It is the season for football which is often called the national sport because of its popularity.I usually watch television and read the newspaper reports about the football results of the little leagues.During the summer I like to go to the beach often because it is very close to my home.I usually go there during the summer vacation to relax after many months in school in the city.I feel very comfortable with the familiar quiet life of the villagers.夏天是戶外運動最好的季節.這是一個橄欖球的季節,橄欖球由于廣受歡迎被稱為全民運動.我常常看電視,看報紙,從報道中獲得小聯盟橄欖球賽的比賽結果.夏日里,我喜歡經常去海灘,因為那里離我家不遠.在城里的學校呆了幾個月后,暑假我常常去那里放松一下.此處有我很熟悉的村民們的寧靜生活,這讓我倍感舒適.9.I think smiling is as important as sunshine.Smiling is like sunshine because it can make people happy and have a good day.If you aren’t happy, you can smile, and then you will feel happy.Someone may say, “But I don’t feel happy.” Then I would say, “Please smile as you do when you are happy or play with your friends happily.You will really be happy again.”

Smiling can let you have more friends.So I say, smiling is like a flower.It will give you happiness.我認為微笑是一樣重要的象陽光。微笑是象陽光，因為它可能使人愉快和有一個早晨好。如果您不是愉快的，您能微笑，您然后將感覺愉快。某人也許說，“但是我不感到愉快”。然后我會說，“請微笑，您，當您愉快地是愉快或戲劇與您的朋友。您真正地再將是愉快的”。微笑可能讓您有更多朋友。如此我說，微笑是象花。它將給您幸福

10.My family are going to Hainan.It's a good seaside city.We are staying there for a week.We are going to the beach and going swimming in the sea.We're visiting Tianya Haijiao，Wanquan River and many other beautiful places.I think we'll have a good time there.國慶節來了，我有七天的假期。

我們一家去海南。那是一個美麗的海濱城市。我們在那里待上一個星期。我們去沙灘，還在海里游泳。我們游覽“天涯海角”，菀泉河還有別的許多好地方。我想我們在那里會玩得很開心 11.I'm now living in a small house with my parents.It has three floors with five bedrooms, three bathrooms, two big dining rooms and two living rooms.When my friends come to visit me, I will have enough bedrooms for them.We'll have a good time.Besides that, we will have a swimming pool behind the house and a garden in front of the house.In the morning, my parents can do some exercise in the garden.The air must be very fresh.When we feel tired, we can have a swim in the swimming pool.Life will be easy for us.I'll study harder than before so that the dream can come true.我現在和我的父母生活在一個小房子。

它有三層,有五個臥室,三個衛生間,兩個大的餐廳和兩個客廳。當我的朋友來看望我,我將有足夠的臥室。我們將有一個美好的時光。除此之外,我們將房子后面有一個游泳池和一個花園在房子的前面。在早上,我的父母在花園里可以做一些運動。空氣一定很新鮮。當我們感到疲倦的時候,我們可以在游泳池里游泳。生活對我們來說會很容易。我會比以前更努力學習,夢想可以成真。

12.I am now 14 years old.Yesterday was my birthday.My parents had a birthday party.I invited my friends to attend.My mother got up very early in the morning, and began to cook.My father to help her cooking.They are very busy.All my friends arrived, my mother brought food and a cake.My father gave me new clothes and some books as my birthday gift.My friends sang birthday songs for me, gave me some presents.I have a wonderful birthday.我現在14歲。昨天是我的生日。我的父母有一個生日聚會。我邀請朋友們參加。在早上我的媽媽起得很早,開始做飯。我父親幫她做飯。他們很忙。

我的所有朋友都到了以后,媽媽端上食物和一個蛋糕。爸爸送給我新衣服和書作為生日禮物。我的朋友為我唱生日歌,給了我一些禮物。我有一個美好的生日。

13.I have a busy and interesting summer vacation.I do my homework every day, so I finished my homework ten days before the new term.I also every day and my friends to play table tennis and basketball.I sometimes go to the movies, and my friends went to the park.I browse the Internet, read books and watch TV every evening.I help my parents clean the room and cooking.我有一個忙碌而有趣的暑假。我每天做我的作業,所以我做完作業前十天新學期。我也每天都和我的朋友打乒乓球和籃球。我有時去看電影,和我的朋友去了公園。我瀏覽互聯網,閱讀書籍,每天晚上看電視。我幫助我的父母打掃房間和做飯。

14.Hello, boys and girls!My name is lu.I'm 14 years old.My birthday is on November 7.I am a movie fan.I like action movies and science fiction movies.My favorite actor is Jackie chan.He is a great action actor.He has many movies.For example: “the 80 days around the world”, “baby plan andRush hour”.The movie is very exciting.I really like baby plans, because they are exciting.I like action movies very much 你好,男孩和女孩!我的名字是科陸。我14歲。我的生日是11月7日。我是一個電影迷。我喜歡動作電影和科幻電影。我最喜歡的演員是成龍。他是一個偉大的行動的演員。他有許多電影。

為例：《世界各地的80天》,《寶貝計劃andRush小時》。這些電影非常令人興奮。我真的很喜歡寶貝計劃,因為它們是令人興奮的。我非常喜歡動作片電影。

15.It is about half past four.It is time to exercise.The students on the playground.They are playing a football match.Atom is one of them.He is good at football.He in the school football team.Atom and said, I like to play football.It is one of my favorite sports.Panchen and hao-ling wang friend, he is a football fan.Ronaldo is his favourite player.它大約是4點半。是時候運動。學生們在操場上。他們是在玩一場足球比賽。凌動就是其中之一。他擅長足球。他在學校的足球隊。凌動說,我喜歡踢足球。它是我最喜歡的運動。**和王浩凌動的朋友,他是一個足球迷。羅納爾多是他最喜歡的球員。

16.Today is the first day of Chinese New Year.I am wearing new sweaters and shoes.Some people always put the gifts, smiling at everyone.They wear red clothes.You can play with fireworks, but don't play in the room.We can eat a lot of Chinese food, rice dumplings, dumplings.Today is a beautiful day.今天是中國新年的第一天。我穿著新毛衣和鞋子。一些人總是把禮物,對每個人微笑。他們穿著紅色的衣服。

你可以玩煙花,但不要在房間里玩。我們可以吃很多中國菜,啊粽子、餃子.今天是一個美好的一天

17.There are 55 students in my class.We study together.We play together.We talk to each other.We help each other.Our class is like a big family.We are very happy.We have a lot of the teacher.They are very kind.They are always good for us.They make us very very hard study.有55名學生在我的班。我們一起研究。我們一起玩。我們相互交談。我們互相幫助。我們班就像一個大家庭。我們非常高興。

我們有很多老師。他們非常善良。他們總是對我們好。他們讓我們非常非常努力學習。

18.piano and I good at it.So I want to become a piano player.Play the piano is very interesting.And you can learn something of music.Piano can make you like music.A lot of musician and singer are love playing piano.Become a piano play is a hard job.But I believe I can do it.鋼琴,我擅長它。所以我想成為一個鋼琴家。彈鋼琴是非常有趣的。你可以學習一些音樂。鋼琴能讓你喜歡音樂。許多音樂家和歌手都喜歡彈鋼琴。成為一個鋼琴演奏是一個辛苦的工作。但是我相信我能做到。

19.Oh!My god.Last Sunday my toothbrush is broken.I can't brush your teeth.So I went shopping with my mother.There are so many toothbrush.Finally, we chose a blue one.I like it very much.So we bought it.My mom says it's good for my teeth.Then we went home.Can I brush my teeth.I'm so happy!哦!我的神。上星期天我的牙刷壞了，我不能刷牙。所以我和我的媽媽去購物.有這么多牙刷。最后,我們選擇了一個藍色的。我非常喜歡它。所以我們買了它。我媽媽說它對我的牙齒有好處。然后我們就回家了。我可以刷我的牙齒。我真快樂!20.We all have neighbors.Neighbors get along well with each other.My neighbour has a daughter.We are the same age, we study in the same school.In the evening we always do homework together.So we often help each other.我們都有鄰居。鄰居彼此相處得很好。我的鄰居有一個女兒。我們是同樣的年齡,我們在同一所學校學習。在晚上我們總是在一起做作業。所以我們經常互相幫助。

第三篇：英語政府官員職位中英文翻譯

英語政府官員職位中英文翻譯

英美雖都是講英語國家，但同一政府部門的首長名稱不同：英國國家元首是國王（King）或女王（Queen），而美國的國家元首是總統（President）。英國內閣的首腦為首相（Prime Minister），其他組成人有：

First Lord of the Treasury 第一財政大臣（首相兼任）

Secretary of State for Foreign Affairs 外交大臣

Lord President of the Council 樞密院大臣

Lord Chancellor 大法官

Chancellor of the Exchequer 財政大臣

Chancellor of the Duchy of Lancaster 蘭開斯特公爵郡大臣

Lord Privy Seal and Leader of the House of Commons 掌皇大臣兼下院領袖

Minister of Defense 國防大臣

Secretary of state for Commonwealth Relations 聯邦關系事務大臣

Secretary of State for the Colonies 殖民地事務大臣

Secretary of State for Scotland 蘇格蘭事務大臣

Minister of Labor and National Service 勞工大臣

Minister for Housing and Local Government 住房及地方政府事物大臣

Minister of Town and Country Planning 都市及鄉村計劃大臣

Minister of Health 衛生大臣

Minister of Education 教育大臣

President of the Board of Trade 貿易大臣

Minister of Agriculture and Fisheries 農業和漁業大臣

Minister of Pensions and National Insurance 年金及國民保險大臣 此外還有非內閣閣員的政府部門首長 ：

First Lord Of the Admiralty 海軍大臣

Secretary of State for War 陸軍大臣

Secretary of State for Air 空軍大臣

Minister of Fuel and Power 燃料電力大臣

Minister of Transport 運輸大臣

Minister of Supply 供應大臣

Minister of Economic Affairs 經濟事務大臣

Minister of Food 糧食大臣

Minister of Civil Aviation 民航大臣

Minister of Works 工程大臣

Paymaster General 主計大臣

Labor secretary 勞工部長

Postmaster General 郵政大臣

Attorney — General 檢查總長

Solicitor — General 副檢查總長

Lord Advocate 蘇格蘭檢察總長

美國總統以下設十個行政主管，分掌國政，形成一個內閣：

Secretary of State 國務卿

Secretary of the Treasury 財政部長

Secretary of Defense 國防部長

Attorney General 司法部長

Postmaster General 郵政管理局長

Interior Secretary 內政部長

Agriculture Secretary 農業部長

Commerce Secretary 商務部長

第四篇：中英文翻譯

Fundamentals This chapter describes the fundamentals of today’s wireless communications.First a detailed description of the radio channel and its modeling are presented, followed by the introduction of the principle of OFDM multi-carrier transmission.In addition, a general overview of the spread spectrum technique, especially DS-CDMA, is given and examples of potential applications for OFDM and DS-CDMA are analyzed.This introduction is essential for a better understanding of the idea behind the combination of OFDM with the spread spectrum technique, which is briefly introduced in the last part of this chapter.1.1 Radio Channel Characteristics Understanding the characteristics of the communications medium is crucial for the appropriate selection of transmission system architecture, dimensioning of its components, and optimizing system parameters, especially since mobile radio channels are considered to be the most difficult channels, since they suffer from many imperfections like multipath fading, interference, Doppler shift, and shadowing.The choice of system components is totally different if, for instance, multipath propagation with long echoes dominates the radio propagation.Therefore, an accurate channel model describing the behavior of radio wave propagation in different environments such as mobile/fixed and indoor/outdoor is needed.This may allow one, through simulations, to estimate and validate the performance of a given transmission scheme in its several design phases.1.1.1 Understanding Radio Channels In mobile radio channels(see Figure 1-1), the transmitted signal suffers from different effects, which are characterized as follows: Multipath propagation occurs as a consequence of reflections, scattering, and diffraction of the transmitted electromagnetic wave at natural and man-made objects.Thus, at the receiver antenna, a multitude of waves arrives from many different directions with different delays, attenuations, and phases.The superposition of these waves results in amplitude and phase variations of the composite received signal.Doppler spread is caused by moving objects in the mobile radio channel.Changes in the phases and amplitudes of the arriving waves occur which lead to time-variant multipath propagation.Even small movements on the order of the wavelength may result in a totally different wave superposition.The varying signal strength due to time-variant multipath propagation is referred to as fast fading.Shadowing is caused by obstruction of the transmitted waves by, e.g., hills, buildings, walls, and trees, which results in more or less strong attenuation of the signal strength.Compared to fast fading, longer distances have to be covered to significantly change the shadowing constellation.The varying signal strength due to shadowing is called slow fading and can be described by a log-normal distribution [36].Path loss indicates how the mean signal power decays with distance between transmitter and receiver.In free space, the mean signal power decreases with the square of the distance between base station(BS)and terminal station(TS).In a mobile radio channel, where often no line of sight(LOS)path exists, signal power decreases with a power higher than two and is typically in the order of three to five.Variations of the received power due to shadowing and path loss can be efficiently counteracted by power control.In the following, the mobile radio channel is described with respect to its fast fading characteristic.1.1.2 Channel Modeling The mobile radio channel can be characterized by the time-variant channel impulse response h(τ , t)or by the time-variant channel transfer function H(f, t), which is the Fourier transform of h(τ , t).The channel impulse response represents the response of the channel at time t due to an impulse applied at time t ? τ.The mobile radio channel is assumed to be a wide-sense stationary random process, i.e., the channel has a fading statistic that remains constant over short periods of time or small spatial distances.In environments with multipath propagation, the channel impulse response is composed of a large number of scattered impulses received over Np different paths，Where

and ap, fD,p, ?p, and τp are the amplitude, the Doppler frequency, the phase, and the propagation delay, respectively, associated with path p, p = 0,..., Np ? 1.The assigned channel transfer function is

The delays are measured relative to the first detectable path at the receiver.The Doppler Frequency

depends on the velocity v of the terminal station, the speed of light c, the carrier frequency fc, and the angle of incidence αp of a wave assigned to path p.A channel impulse response with corresponding channel transfer function is illustrated in Figure 1-2.The delay power density spectrum ρ(τ)that characterizes the frequency selectivity of the mobile radio channel gives the average power of the channel output as a function of the delay τ.The mean delay τ , the root mean square(RMS)delay spread τRMS and the maximum delay τmax are characteristic parameters of the delay power density spectrum.The mean delay is

Where

Figure 1-2 Time-variant channel impulse response and channel transfer function with frequency-selective fading is the power of path p.The RMS delay spread is defined as Similarly, the Doppler power density spectrum S(fD)can be defined that characterizes the time variance of the mobile radio channel and gives the average power of the channel output as a function of the Doppler frequency fD.The frequency dispersive properties of multipath channels are most commonly quantified by the maximum occurring Doppler frequency fDmax and the Doppler spread fDspread.The Doppler spread is the bandwidth of the Doppler power density spectrum and can take on values up to two times |fDmax|, i.e.，1.1.3Channel Fade Statistics The statistics of the fading process characterize the channel and are of importance for channel model parameter specifications.A simple and often used approach is obtained from the assumption that there is a large number of scatterers in the channel that contribute to the signal at the receiver side.The application of the central limit theorem leads to a complex-valued Gaussian process for the channel impulse response.In the absence of line of sight(LOS)or a dominant component, the process is zero-mean.The magnitude of the corresponding channel transfer function

is a random variable, for brevity denoted by a, with a Rayleigh distribution given by

Where

is the average power.The phase is uniformly distributed in the interval [0, 2π].In the case that the multipath channel contains a LOS or dominant component in addition to the randomly moving scatterers, the channel impulse response can no longer be modeled as zero-mean.Under the assumption of a complex-valued Gaussian process for the channel impulse response, the magnitude a of the channel transfer function has a Rice distribution given by

The Rice factor KRice is determined by the ratio of the power of the dominant path to thepower of the scattered paths.I0 is the zero-order modified Bessel function of first kind.The phase is uniformly distributed in the interval [0, 2π].1.1.4Inter-Symbol(ISI)and Inter-Channel Interference(ICI)The delay spread can cause inter-symbol interference(ISI)when adjacent data symbols overlap and interfere with each other due to different delays on different propagation paths.The number of interfering symbols in a single-carrier modulated system is given by

For high data rate applications with very short symbol duration Td < τmax, the effect of ISI and, with that, the receiver complexity can increase significantly.The effect of ISI can be counteracted by different measures such as time or frequency domain equalization.In spread spectrum systems, rake receivers with several arms are used to reduce the effect of ISI by exploiting the multipath diversity such that individual arms are adapted to different propagation paths.If the duration of the transmitted symbol is significantly larger than the maximum delay Td τmax, the channel produces a negligible amount of ISI.This effect is exploited with multi-carrier transmission where the duration per transmitted symbol increases with the number of sub-carriers Nc and, hence, the amount of ISI decreases.The number of interfering symbols in a multi-carrier modulated system is given by

Residual ISI can be eliminated by the use of a guard interval(see Section 1.2).The maximum Doppler spread in mobile radio applications using single-carrier modulation is typically much less than the distance between adjacent channels, such that the effect of interference on adjacent channels due to Doppler spread is not a problem for single-carrier modulated systems.For multi-carrier modulated systems, the sub-channel spacing Fs can become quite small, such that Doppler effects can cause significant ICI.As long as all sub-carriers are affected by a common Doppler shift fD, this Doppler shift can be compensated for in the receiver and ICI can be avoided.However, if Doppler spread in the order of several percent of the sub-carrier spacing occurs, ICI may degrade the system performance significantly.To avoid performance degradations due to ICI or more complex receivers with ICI equalization, the sub-carrier spacing Fs should be chosen as

such that the effects due to Doppler spread can be neglected(see Chapter 4).This approach corresponds with the philosophy of OFDM described in Section 1.2 and is followed in current OFDM-based wireless standards.Nevertheless, if a multi-carrier system design is chosen such that the Doppler spread is in the order of the sub-carrier spacing or higher, a rake receiver in the frequency domain can be used [22].With the frequency domain rake receiver each branch of the rake resolves a different Doppler frequency.1.1.5Examples of Discrete Multipath Channel Models Various discrete multipath channel models for indoor and outdoor cellular systems with different cell sizes have been specified.These channel models define the statistics of the 5 discrete propagation paths.An overview of widely used discrete multipath channel models is given in the following.COST 207 [8]: The COST 207 channel models specify four outdoor macro cell propagation scenarios by continuous, exponentially decreasing delay power density spectra.Implementations of these power density spectra by discrete taps are given by using up to 12 taps.Examples for settings with 6 taps are listed in Table 1-1.In this table for several propagation environments the corresponding path delay and power profiles are given.Hilly terrain causes the longest echoes.The classical Doppler spectrum with uniformly distributed angles of arrival of the paths can be used for all taps for simplicity.Optionally, different Doppler spectra are defined for the individual taps in [8].The COST 207 channel models are based on channel measurements with a bandwidth of 8–10 MHz in the 900-MHz band used for 2G systems such as GSM.COST 231 [9] and COST 259 [10]: These COST actions which are the continuation of COST 207 extend the channel characterization to DCS 1800, DECT, HIPERLAN and UMTS channels, taking into account macro, micro, and pico cell scenarios.Channel models with spatial resolution have been defined in COST 259.The spatial component is introduced by the definition of several clusters with local scatterers, which are located in a circle around the base station.Three types of channel models are defined.The macro cell type has cell sizes from 500 m up to 5000 m and a carrier frequency of 900 MHz or 1.8 GHz.The micro cell type is defined for cell sizes of about 300 m and a carrier frequency of 1.2 GHz or 5 GHz.The pico cell type represents an indoor channel model with cell sizes smaller than 100 m in industrial buildings and in the order of 10 m in an office.The carrier frequency is 2.5 GHz or 24 GHz.COST 273: The COST 273 action additionally takes multi-antenna channel models into account, which are not covered by the previous COST actions.CODIT [7]: These channel models define typical outdoor and indoor propagation scenarios for macro, micro, and pico cells.The fading characteristics of the various propagation environments are specified by the parameters of the Nakagami-m distribution.Every environment is defined in terms of a number of scatterers which can take on values up to 20.Some channel models consider also the angular distribution of the scatterers.They have been developed for the investigation of 3G system proposals.Macro cell channel type models have been developed for carrier frequencies around 900 MHz with 7 MHz bandwidth.The micro and pico cell channel type models have been developed for carrier frequencies between 1.8 GHz and 2 GHz.The bandwidths of the measurements are in the range of 10–100 MHz for macro cells and around 100 MHz for pico cells.JTC [28]: The JTC channel models define indoor and outdoor scenarios by specifying 3 to 10 discrete taps per scenario.The channel models are designed to be applicable for wideband digital mobile radio systems anticipated as candidates for the PCS(Personal Communications Systems)common air interface at carrier frequencies of about 2 GHz.UMTS/UTRA [18][44]: Test propagation scenarios have been defined for UMTS and UTRA system proposals which are developed for frequencies around 2 GHz.The modeling of the multipath propagation corresponds to that used by the COST 207 channel models.HIPERLAN/2 [33]: Five typical indoor propagation scenarios for wireless LANs in the 5 GHz frequency band have been defined.Each scenario is described by 18discrete taps of the delay power density spectrum.The time variance of the channel(Doppler spread)is modeled by a classical Jake’s spectrum with a maximum terminal speed of 3 m/h.Further channel models exist which are, for instance, given in [16].1.1.6Multi-Carrier Channel Modeling Multi-carrier systems can either be simulated in the time domain or, more computationally efficient, in the frequency domain.Preconditions for the frequency domain implementation are the absence of ISI and ICI, the frequency nonselective fading per sub-carrier, and the time-invariance during one OFDM symbol.A proper system design approximately fulfills these preconditions.The discrete channel transfer function adapted to multi-carrier signals results in

where the continuous channel transfer function H(f, t)is sampled in time at OFDM symbol rate s and in frequency at sub-carrier spacing Fs.The duration

s is the total OFDM symbol duration including the guard interval.Finally, a symbol transmitted onsub-channel n of the OFDM symbol i is multiplied by the resulting fading amplitude an,i and rotated by a random phase ?n,i.The advantage of the frequency domain channel model is that the IFFT and FFT operation for OFDM and inverse OFDM can be avoided and the fading operation results in one complex-valued multiplication per sub-carrier.The discrete multipath channel models introduced in Section 1.1.5 can directly be applied to(1.16).A further simplification of the channel modeling for multi-carrier systems is given by using the so-called uncorrelated fading channel models.1.1.6.1Uncorrelated Fading Channel Models for Multi-Carrier Systems These channel models are based on the assumption that the fading on adjacent data symbols after inverse OFDM and de-interleaving can be considered as uncorrelated [29].This assumption holds when, e.g., a frequency and time interleaver with sufficient interleaving depth is applied.The fading amplitude an,i is chosen from a distribution p(a)according to the considered cell type and the random phase ?n,I is uniformly distributed in the interval [0,2π].The resulting complex-valued channel fading coefficient is thus generated independently for each sub-carrier and OFDM symbol.For a propagation scenario in a macro cell without LOS, the fading amplitude an,i is generated by a Rayleigh distribution and the channel model is referred to as an uncorrelated Rayleigh fading channel.For smaller cells where often a dominant propagation component occurs, the fading amplitude is chosen from a Rice distribution.The advantages of the uncorrelated fading channel models for multi-carrier systems are their simple implementation in the frequency domain and the simple reproducibility of the simulation results.1.1.7Diversity The coherence bandwidth of a mobile radio channel is the bandwidth over which the signal propagation characteristics are correlated and it can be approximated by

The channel is frequency-selective if the signal bandwidth B is larger than the coherence bandwidth.On the other hand, if B is smaller than , the channel is frequency nonselective or flat.The coherence bandwidth of the channel is of importance for evaluating the performance of spreading and frequency interleaving techniques that try to exploit the inherent frequency diversity Df of the mobile radio channel.In the case of multi-carrier transmission, frequency diversity is exploited if the separation of sub-carriers transmitting the same information exceeds the coherence bandwidth.The maximum achievable frequency diversity Df is given by the ratio between the signal bandwidth B and the coherence bandwidth，The coherence time of the channel is the duration over which the channel characteristics can be considered as time-invariant and can be approximated by

If the duration of the transmitted symbol is larger than the coherence time, the channel is time-selective.On the other hand, if the symbol duration is smaller than , the channel is time nonselective during one symbol duration.The coherence time of the channel is of importance for evaluating the performance of coding and interleaving techniques that try to exploit the inherent time diversity DO of the mobile radio channel.Time diversity can be exploited if the separation between time slots carrying the same information exceeds the coherence time.A number of Ns successive time slots create a time frame of duration Tfr.The maximum time diversity Dt achievable in one time frame is given by the ratio between the duration of a time frame and the coherence time, A system exploiting frequency and time diversity can achieve the overall diversity

The system design should allow one to optimally exploit the available diversity DO.For instance, in systems with multi-carrier transmission the same information should be transmitted on different sub-carriers and in different time slots, achieving uncorrelated faded replicas of the information in both dimensions.Uncoded multi-carrier systems with flat fading per sub-channel and time-invariance during one symbol cannot exploit diversity and have a poor performance in time and frequency selective fading channels.Additional methods have to be applied to exploit diversity.One approach is the use of data spreading where each data symbol is spread by a spreading code of length L.This, in combination with interleaving, can achieve performance results which are given for

by the closed-form solution for the BER for diversity reception in Rayleigh fading channels according to [40]

Whererepresents the combinatory function，and σ2 is the variance of the noise.As soon as the interleaving is not perfect or the diversity offered by the channel is smaller than the spreading code length L, or MCCDMA with multiple access interference is applied,(1.22)is a lower bound.For L = 1, the performance of an OFDM system without forward error correction(FEC)is obtained, 9

which cannot exploit any diversity.The BER according to(1.22)of an OFDM(OFDMA, MC-TDMA)system and a multi-carrier spread spectrum(MC-SS)system with different spreading code lengths L is shown in Figure 1-3.No other diversity techniques are applied.QPSK modulation is used for symbol mapping.The mobile radio channel is modeled as uncorrelated Rayleigh fading channel(see Section 1.1.6).As these curves show, for large values of L, the performance of MC-SS systems approaches that of an AWGN channel.Another form of achieving diversity in OFDM systems is channel coding by FEC, where the information of each data bit is spread over several code bits.Additional to the diversity gain in fading channels, a coding gain can be obtained due to the selection of appropriate coding and decoding algorithms.中文翻譯 1基本原理

這章描述今日的基本面的無線通信。第一一個的詳細說明無線電頻道，它的模型被介紹，跟隨附近的的介紹的原則的參考正交頻分復用多載波傳輸。此外，一個一般概觀的擴頻技術，尤其ds-cdma，被給，潛力的例子申請參考正交頻分復用，DS對1。分配的通道傳輸功能是

有關的延誤測量相對于第一個在接收器檢測到的路徑。多普勒頻率

取決于終端站，光速c，載波頻率fc的速度和發病路徑分配給速度v波αp角度頁具有相應通道傳輸信道沖激響應函數圖1-2所示。

延遲功率密度譜ρ（τ）為特征的頻率選擇性移動無線電頻道給出了作為通道的輸出功能延遲τ平均功率。平均延遲τ，均方根（RMS）的時延擴展τRMS和最大延遲τmax都是延遲功率密度譜特征參數。平均時延特性參數為

有

圖1-2時變信道沖激響應和通道傳遞函數頻率選擇性衰落是權力頁的路徑均方根時延擴展的定義為 同樣，多普勒頻譜的功率密度（FD）的特點可以定義

在移動時變無線信道，并給出了作為一種金融衍生工具功能的多普勒頻率通道輸出的平均功率。多徑信道頻率分散性能是最常見的量化發生的多普勒頻率和多普勒fDmax蔓延fDspread最大。多普勒擴散是功率密度的多普勒頻譜帶寬，可價值觀需要兩年時間| fDmax|，即

1.1.3頻道淡出統計

在衰落過程中的統計特征和重要的渠道是信道模型參數規格。一個簡單而經常使用的方法是從假設有一個通道中的散射，有助于在大量接收端的信號。該中心極限定理的應用導致了復雜的值的高斯信道沖激響應過程。在對視線（LOS）或線的主要組成部分的情況下，這個過程是零的意思。相應的通道傳遞函數幅度

是一個隨機變量，通過給定一個簡短表示由瑞利分布，有

是的平均功率。相均勻分布在區間[0，2π]。

在案件的多通道包含洛杉磯的或主要組件除了隨機移動散射，通道脈沖響應可以不再被建模為均值為零。根據信道脈沖響應的假設一個復雜的值高斯過程，其大小通道的傳遞函數A的水稻分布給出

賴斯因素KRice是由占主導地位的路徑權力的威力比分散的路徑。I0是零階貝塞爾函數的第一階段是一致kind.The在區間[0，2π]分發。

1.1.4符號間（ISI）和通道間干擾（ICI）

延遲的蔓延引起的符號間干擾（ISI）當相鄰的數據符號上的重疊與互相不同的傳播路徑，由于不同的延遲干涉。符號的干擾在單載波調制系統的號碼是給予

對于高數據符號持續時間很短運輸署<蟿MAX時，ISI的影響，這樣一來，速率應用，接收機的復雜性大大增加。對干擾影響，可以抵消，如時間或頻域均衡不同的措施。在擴頻系統，與幾個臂Rake接收機用于減少通過利用多徑分集等，個別武器適應不同的傳播路徑的干擾影響。

如果發送符號的持續時間明顯高于大的最大延遲運輸署蟿最大，渠道產生ISI的微不足道。這種效果是利用多載波傳輸的地方，每發送符號的增加與子載波數控數目，因此，ISI的金額減少的持續時間。符號的干擾多載波調制系統的號碼是給予

可以消除符號間干擾由一個保護間隔（見1.2節）的使用。

最大多普勒在移動無線應用傳播使用單載波調制通常比相鄰通道，這樣，干擾對由于多普勒傳播相鄰通道的作用不是一個單載波調制系統的問題距離。對于多載波調制系統，子通道間距FS可以變得非常小，這樣可以造成嚴重的多普勒效應ICI的。只要所有子載波只要是一個共同的多普勒頻移金融衍生工具的影響，這可以補償多普勒頻移在接收器和ICI是可以避免的。但是，如果在對多普勒子載波間隔為幾個百分點的蔓延情況，卜內門可能會降低系統的性能顯著。為了避免性能降級或因與ICI卜內門更復雜的接收機均衡，子載波間隔財政司司長應定為

這樣說，由于多普勒效應可以忽略不擴散（見第4章）。這種方法對應于OFDM的1.2節中所述，是目前基于OFDM的無線標準遵循的理念。

不過，如果多載波系統的設計選擇了這樣的多普勒展寬在子載波間隔或更高，秩序是在頻率RAKE接收機域名可以使用[22]。隨著頻域RAKE接收機每個支部耙解決了不同的多普勒頻率。

1.1.5多徑信道模型的離散的例子

各類離散多與不同的細胞大小的室內和室外蜂窩系統的信道模型已經被指定。這些通道模型定義的離散傳播路徑的統計信息。一種廣泛使用的離散多徑信道模型概述于下。造價207[8]：成本207信道模型指定連續四個室外宏蜂窩傳播方案，指數下降延遲功率密度譜。這些頻道功率密度的離散譜的實現都是通過使用多達12個頻道。與6頻道設置的示例列于表1-1。在這種傳播環境的幾個表中的相應路徑延遲和電源配置給出。丘陵地形導致最長相呼應。

經典的多普勒頻譜與均勻分布的到達角路徑可以用于簡化所有的頻道。或者，不同的多普勒譜定義在[8]個人頻道。207信道的成本模型是基于一個8-10兆赫的2G，如GSM系統中使用的900兆赫頻段信道帶寬的測量。造價231[9]和造價259[10]：這些費用是行動的延續成本207擴展通道特性到DCS1800的DECT，HIPERLAN和UMTS的渠道，同時考慮到宏觀，微觀和微微小區的情況為例。空間分辨率與已定義的通道模型在造價259。空間部分是介紹了與當地散射，這是在基站周圍設幾組圓的定義。三種類型的通道模型定義。宏細胞類型具有高達500?5000米，載波頻率為900兆赫或1.8 GHz的單元尺寸。微細胞類型被定義為細胞體積約300米，1.2 GHz或5 GHz載波頻率。細胞類型代表的Pico與細胞體積小于100工業建筑物和辦公室中的10 m階米室內信道模型。載波頻率為2.5 GHz或24千兆赫。造價273：成本273行動另外考慮到多天線信道模型，這是不是由先前的費用的行為包括在內。

CODIT [7]：這些通道模型定義的宏，微，微微蜂窩和室外和室內傳播的典型案例。各種傳播環境的衰落特性是指定的在NakagamiSS）的不同擴頻碼L是長度，如圖1-3所示的系統。沒有其他的分集技術被應用。QPSK調制用于符號映射。移動無線信道建模為不相關瑞利衰落信道（見1.1.6）。由于這些曲線顯示，辦法，AWGN信道的一對L時，對MC-SS系統性能有很大價值。

另一種實現形式的OFDM系統的多樣性是由前向糾錯信道編碼，在這里，每個數據位的信息分散在幾個代碼位。附加在衰落信道分集增益，編碼增益一個可因適當的編碼和解碼算法的選擇。

第五篇：中英文翻譯

蓄電池 battery 充電 converter 轉換器 charger

開關電器 Switch electric 按鈕開關 Button to switch 電源電器 Power electric 插頭插座 Plug sockets