A very important feature of adaptive modulation and coding (AMC) or adaptive modulation and coding wireless channel is its strong time variation, and the Rayleigh fading can reach ten or even dozens of dB in a short time. Adaptive tracking of this time-varying characteristic will bring great benefits to the improvement of system performance. There are many methods of link adaptation technology, such as power control and AMC. Based on the fixed modulation coding scheme of the original system, HSDPA introduces more code strings and 16QAM modulation, so that the system can track the link changes adaptively by changing the coding mode and modulation order. AMC in TD-SCDMA system has two main advantages: (1) users in favorable position can get higher data rate and improve the average cell throughput. (2) Link adaptive technology can greatly reduce interference by using different high-order modulation schemes instead of the original scheme of changing transmission power. The introduction and implementation of AMC need a lot of supplements to the original system, such as channel measurement and feedback channel quality indication at tie end, and coding and modulation for packet transmission at Node B end according to the reported channel quality indication. This adaptive operation process of AMC can be simply described as follows: (1) The terminal UE receives the message of the downlink high-speed shared control channel (HS-SCCH) and indicates the resource allocation of the next high-speed downlink * * * shared channel (HS-DSCH); (2)UE performs corresponding channel measurement, which can be obtained through the pilot channel; (3) According to the HS-DSCH resource allocation and measurement results, the UE generates a channel quality indicator (CQI) and reports it to the Node B on the corresponding HS-SICH (High Speed Shared Information Channel). The CQI includes the transport block size and modulation format suggested by the UE; (4) (4) The upper layer of Node B selects an appropriate transmission format according to the CQI report of UE; (5)Node B carries the control information of the UE on the downlink control channel HS-SCCH and sends it to the UE in the corresponding transmission format on the allocated HS-DSCH TTI.
American Mathematics Competitions
brief introduction
The abbreviation of American Mathematics Competition, also known as American High School Mathematics Examination, was established by American Mathematical Association on 1950. Headquartered at the University of Nebraska at Lincoln, it is directly affiliated to the American Mathematical Association. 1985 added American junior high school math exam (Ajhsme). Every year, in North America alone, more than 600,000 students are officially registered to take the exam, so AMC is the most reliable and effective math subject exam in the world. There are more than 20 countries in the world, such as Canada, Singapore, Hong Kong, Japan, Hungary, Greece, Turkey and France. This test has been recommended by American middle school principals as one of the main activities every year. Students who score above 100 or rank in the top 5% in the world will be eligible to take the American Mathematics Invitational Examination for free. AIME will be held in AMC in five weeks. The examination time is 3 hours, and the competition question is "15", and the answer is an integer from 0 to 999. If you answer a question correctly, you will get 1 point, and if you answer it incorrectly, you will not be deducted. The perfect score is 15. The test questions are quite difficult. AMC and AIME are both part of the International Mathematical Olympiad (IMO) national team trials.
Historical overview of AMC
1950, a branch of the American Mathematical Association set up a math competition for senior high school students-AHSME (originally 50 multiple-choice questions, 1974 changed to 30 multiple-choice questions, and after 2000, there were 25 multiple-choice questions. 1985 added an activity for junior high school students-American junior high school math exam (Ajhsme), which lasted until 1999 China attended AMC memorabilia: 1983. 1 Aimei Shanghai, 1984, 1 10 Second Aimei, 1985, 1 18 Third Aimei Beijing, a total of 76 people. Five students are eligible to take part in the competition. Wu Sihao of Shanghai Xiangming Middle School participated in IMO for the first time in China, and got the full mark of 1992 in the 4th AIME. More than 1000 students in Shanghai have qualified for the competition, including Pan from Gezhi Middle School and Zhang Jue from the middle school affiliated to Jiaotong University. Kim Ching Ko 1993 in a middle school in Shanghai. 1 Aimei Shanghai A total of 1000 students were eligible for the competition, including Wang Haidong, a senior 3 student from the Second Affiliated Middle School of East China Normal University, Huang Jing, a female senior 3 student from Gezhi Middle School, Sean, a senior 3 student from Xishi Middle School and Han Zhigang, a senior 3 student from Fudan High School. The top three students ranked 4 1. On February 5th, 2006, nearly 2,000 middle school students in China participated in the 2006AMC 10(B) and 2006AMC 12(B) competitions respectively. On March 22nd, 2006, nearly 800 middle school students who achieved excellent results in AMC participated in the AIME(2) competition.
AMC American classic movie cable TV station
The full name of AMC cable TV is American movie classic, which is literally translated into American classic movie cable TV. It is a cable TV under Rainbow Media Holdings (LLC), which was established in June 1984+ 10/. As early as the 1980s, AMC Cable TV was originally a pay TV station dedicated to the classic old movies of the 1950s. From 65438 to 0987, AMC Cable TV joined the basic cable TV camp. As long as viewers pay a certain fee to the cable TV system service provider, they can watch AMC cable TV programs without paying extra. Due to the reduction of fees, it attracted a large number of viewers to subscribe to the channel. By 1989, there were more than 39 million subscribers in the United States. In the 1990s, AMC cable channels played a lot of wonderful movies to the audience, which mainly came from Paramount Pictures, 20th Century Fox and Universal Studios. At the same time, AMC cable TV began to produce some TV series. 1996, AMC Cable produced its first TV series "Remember WENN", which tells the story of media workers under the background of World War II. As soon as the play came out, it was well received by the industry and won an Emmy Award. In addition, AMC Cable has also launched some movie theme weeks, such as horror movie theme week, which is also very popular. Not only that, some movie trailers, movie music, etc. also enriched the screen of AMC cable station. During the period after 2000, AMC Cable TV began to adjust its media strategy, began to broadcast some more popular movies to attract more viewers, and began to insert a small number of commercial advertisements into TV programs. On September 1 day, 2006, AMC Cable went out of the United States and landed in Canada through a local Canadian TV service provider, which expanded its audience. During this period, AMC Cable produced more self-made TV series and TV programs, such as AMC Backstory, Shootout broadcast from 2000 to 2004, and Breaking Bad released in 2003. What's more, in 2007, AMC Cable TV launched the TV series Mad Men, which described American advertisers in the 1960s. This drama can be described as a "revolutionary" TV work, which was not only well received by the industry, but also won the Emmy Award for Best Drama in 2008, breaking the previous dominance of wireless TV networks and pay stations such as HBO and SHOWTIME in the Emmy Awards. In the autumn of 20 10, the American TV series The Walking Dead, which was adapted from comics, was released, including the heroine in Prison Break, which caused quite a wave of viewing frenzy in China.
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The abbreviation of Australian Mathematics Competition is AMC, the abbreviation of asset management company. In the football manager's competition, AM C is usually an attacking midfielder, which is also the abbreviation of "vanguard" or "front waist". More atlas