Channel Estimation in OFDM Systems Using Compressive Sampling Technique

• Main Author: 闕瑞慶
• Other Authors: Wu,Wen-Rong
• Format: Others
• Language: en_US
• Published: 2010
• Online Access: http://ndltd.ncl.edu.tw/handle/29283777605763268047

碩士 === 國立交通大學 === 電信工程研究所 === 98 === In pilot-assisted OFDM systems, the channel estimation problem is usually solved by the using the pilot subcarriers inserted in OFDM symbols. However, more pilots used will lead to lower transmission rate, and the number of pilots is sometimes limited due to the systems. So we are facing a problem to accurately estimate the channel response while using a small number of pilots. Recently, a novel technique called compressive sampling (CS) has emerged, asserting to recover the sparse signals with a few measurements. Since the number of non-zero taps in time-domain channel response is small, we can then apply the CS methods to the channel estimation problem in OFDM systems. In this thesis, we propose using a subspace pursuit (SP) algorithm which is shown to be superior to the existing CS methods in channel estimation. The performance of proposed method is also shown to be good when pilot density is very low by adding a decision-feedback mechanism. Then, our problem is extended to the time-variant case. And simulation results show the proposed method performs well even when the speed of mobility is high.