在可加性白高斯雜訊環境下降低 WIMAX 帶外功率之演算法之績效評估

Performance Evaluation of Algorithms for Reduction of Out of Band of WIMAX System Under AWGN Environment

吳慶輝(Ching-Hui Wu)

指導教授 ： 許超雲

大同大學/電機資訊學院/通訊工程研究所/碩士(2011年)

摘要

中文摘要 正交分頻多工是一種高效率的多載波調變技術，資料在子頻帶上被平行傳輸，能有效對抗多重路徑下的符元間干擾和頻率選擇性衰減問題，但此技術也有其必需克服的缺點，例如傳輸訊號在頻域上的帶外功率散逸問題即是一大議題。 本篇論文在探討資料子載波兩邊的各三個零子載波上之雜訊，對強迫為零法、尾隨法、加入消除載波法和訊號空間擴散法之影響，以及在可加性白高斯雜訊環境下降低 WIMAX 帶外功率之演算法之績效評估。主要是在比較符元間連接點平滑、或將傳輸符元的頭尾端資料強迫為零、或將邊界連接點的斜率也強迫趨近於零、加入消除載波的加權因子參數，以及改變調變後資料的相關性的各種降低帶外功率之效益優劣。 由模擬結果顯示，在可加性白高斯雜訊環境下，五種方法對於降低帶外功率的效益，因傳輸環境中頻率點之不同，結果有顯著的差異。

關鍵字

雜訊環境下 ； 降低 WIMAX 帶外功率

並列摘要

ABSTRACT
OFDM is kind of a multi-carrier modulation technique for high data rate transmission.The data transmitted paralleled in sub-carriers. It can effectively against frequency selective fading and inter-symbol interference from multipath. But this technology has its shortcoming that must be overcome. For example, transmit the signal in frequency domain of out of band power issue is one big topic.
This thesis probe into three null subcarriers both sides of data subcarriers with noise. About impact on such as Zero-Forcing Approach、Tail-Tracking Approach、Cancellation Carriers (CCs), and Constellation Expansion (CE). Performance evaluation of algorithms for reduction of out of band of WIMAX system under AWGN environment.We probe into makes the boundary of transmitted symbols continuous, using force as zero at end to end of transmits symbols, join slope clicked in the border to force,Put into the parameter of cancellation carriers,and the CE method expands the constellation of modulation to change dependence of data after modulation.and then performance evaluation of five algorithms for reduction of out of band.
We show from the result of simulation, and then performance evaluation of five algorithms for reduction of out of band under the AWGN environment..The result has apparent differences are according to differential transmit frequency.

並列關鍵字

under AWGN Environment ； Reduction of Out of Band

參考文獻

[1] Chau-Yun Hsu, OFDM-Basis, Lecture materials, Tatung University, Jan. 2010.

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