【正文】 均衡技術。⑥介紹了SCFDE的幀結構，分析比較了采用CP與UW字段的幀結構的異同。⑦為了研究SCFDMA技術，首先概述了LTE的信道類型以及功能，對SCFDMA技術的主要運用的上行鏈路中最復雜最重要的信道，即PUSCH信道進行了簡明扼要地分析，其中包括PUSCH信號的生成，與傳輸流程。⑧繪制了SCFDMA的系統(tǒng)模型，分析了SCFDMA技術的基本原理介紹了SCFDMA的幀結構，給出了相關的參數⑨分析了集中式與分布式子載波映射方式，仿真分析了LFDMA與IFDMA兩種子載波映射方式生成的信號在不同的信道與均衡技術條件下的誤碼率性能。⑩在分析SCFDMA系統(tǒng)誤碼率的同時，比較了SCFDMA符號占用子載波不同位置的誤碼率的系統(tǒng)性能差異，分析了占用首位與第十五位的誤碼率性能。?使用數學方法給出了PAPR的定義，引入了CCDF（互補累積分布函數）來量化PAPR特性，給出了PAPR與功率效率的關系以及SCFDMA的PAPR定義式。?給出了SCFDMA系統(tǒng)PAPR仿真的相關參數，搭建相關仿真平臺，以CCDF形式分析了在相同的條件下，LFDMA，IFDMA，DFDMA與OFDM的PAPR特性的差異。?對比分析了QSK與16QAM調制方式下， SCFDMA與OFDM的PAPR特性。?設置脈沖成形濾波器的滾降系數與類型，仿真其對IFDMA，LFDMA，DFDMA性能的影響。?仿真分析了SCFDMA與OFDMA的PAPR性能差異。出于時間與作者能力的有限，本文對以下方面做得不夠深入，希望在今后的工作或學習中能夠對以下方面有所斬獲：①在仿真中沒有搭建SCFDE仿真平臺，沒有對單載波頻域均衡技術做出誤碼率分析。②在仿真過程中，由于本人的能力有限，只對ZF與MMSE均衡兩種線性均衡技術，在以后的研究中加入了算法性能更好的非線性均衡技術。③LTE系統(tǒng)支持MIMO，可以在以后的仿真中可以加入MIMO，對比一下，MIMO技術對SCFDMA抗多徑效應性能有沒有提升。④在SCFDMA仿真時，出于運行時間的考慮，本來想把輸入數據塊總數設置成10000，但是運行時間過長。于是分析比較了其中一小段，發(fā)現數據塊為10000時，比1000性能好一點，但是不是很明顯，所以出于取舍，就選擇了1000個數據。⑤在SCFDMA仿真時，沒有分析在不同子載波數的情況下的PAPR特性，沒有考慮在沒有脈沖成形的條件下的性能，仿真針對的是單用戶。參考文獻[1]王淑霞. 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To answer that question, I pitted Sprint39。s WiMAX service the first 4G service available in the New York metropolitan area, where I live against its 3G network in a series of realworld tests.Sprint 4G: What you needAs is the case with any wireless service, you need three things to get access: a network, a device for connecting and a service plan. Available in 62 cities, from Everett, Wash., to Tampa, Fla., Sprint39。s WiMAX wireless service in the . is known as Clear and is operated by Clearwire, it39。s based on the IEEE specification. The network provides adequate coverage on the coasts (see map), but it39。s hit or miss in the middle of the country, and there are 12 states with no Sprint 4G service at all.When you can39。t get a 4G connection, the fallback is to use Sprint39。s 3G network, which is based on EVDO (Evolution Data Optimized) technology. It39。s available in all 50 states, although as is the case with other 3G networks there are huge holes in the upper Midwest. Sprint says that over the next two years, it will fill out a national 4G network.In contrast, TMobile currently offers an upgraded High Speed Packet Access (HSPA+) 3G network. ATamp。T is also busy rolling out HSPA+ and is testing LTE (Long Term Evolution) technology for a planned mercial 4G rollout over the next two years.Meanwhile, Verizon has just launched its own LTE network on a trial basis with limited coverage in 38 cities and 60 airports. The pany says the network will be plete nationwide in 2013. Although it39。s not available in my suburb,The second part of the 4G puzzle is the connection device. The Sierra Wireless AirCard 250U modem that I used for testing weighs just oz., connects to a laptop via a USB port, and can be folded up to less than an inch thick when not in use. The diskshaped receiver, which measures about 2 in. across, can rotate and swivel up and down to get better reception. The device has a list price of $250, but it39。s free with a twoyear Sprint contract.The 250U works with systems running Windows 7, Vista or XP, or Mac OS X or . Setting up the 250U on my Lenovo ThinkPad W510 with Windows 7 took about 10 minutes。 it connected to the network on the first try.How I Testedthe 3G EVDO and 4G WiMAX networks. At 10 locations in New York and New Jersey, I fired up my ThinkPad W510 and connected to the 4G network. After noting the signal strength of the connection, I used Ookla39。s utility to measure latency and download and upload speeds. Finally, I watched an online HD video and listened to an Internet radio station.I measured each result three times and then repeated the tests with the 3G network. I returned to each location at three different times over a 10day period and repeated all the tests on both 3G and 4G networks. I also used 3G and 4G connections on a moving muter train and as a passenger in a car and averaged all the results together.To see how connecting with the