Channel Estimation in OFDM Systems Using the Compressed Sensing Technique
| Autor: | Yu-Hsuan Chiang, 蔣宇軒 |
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| Rok vydání: | 2017 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 105 In wireless communication systems, signal transmission suffers from multipath channel interference which degrades the quality of the received signal. To overcome this problem, channel estimation techniques can be employed. Accurate channel estimation can greatly reduce the bit error rate of the received signal and increase the throughput of the whole systems. Compressed sensing (CS) technique has recently gained much attention in various fields. The channel estimation method based on the compressed sensing technique can effectively save the transmission bandwidth while using a fewer pilot symbols in transmission data, because it can make full use of the sparse characteristics of wireless channel. Two modified channel estimation methods based on compressed sensing technique are proposed in this thesis. At first, the orthogonal matching pursuit (OMP) algorithm, one of the CS reconstruction algorithms, is used to estimate the initial value of the channel frequency response. Then, the accuracy of channel impulse response can be improved by using the least mean square (LMS) estimation method. In method 2, the recursive least square (RLS) estimation method is used to find out the actual channel impulse response by iteratively excuting the estimation step. Experimental results indicate that both the proposed schemes can improve the system performance in terms of the bit error rate (BER), compared to least square spline (LS-spline) interpolation, least square linear (LS-linear) interpolation, and the conventional channel estimation method based on compressed sensing technique. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
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