Division Multiplexing Systems
Miao Ke,Zhang Taiyi,Sun Jiancheng,Tang Shaojie
(School of Electronics and Information Engineering,Xi'an Jiaotong University,Xi'an 710049,China)
Abstract:In order to improve the communication efficiency and quality of
orthogonal frequency division multiplexing(OFDM)systems,a pilot-aided OFDM channel
estimation algorithm based on the method of the least square support vector machine (LS¡MSVM)
was presented.Using pilots inserted of OFDM symbol, training data are gained. Depending on
LS¡MSVM,the algorithm maps trained data into a high dimensional space and employs the
principle of structure risk minimization in the space to carry out the regression
estimation for the frequency response function of the time-varying channel.This algorithm
transforms the nonlinear estimation in low dimensional space into the linear estimation in
high dimensional space,so it improves the estimated precision.The simulation result
indicates that this channel estimation algorithm effectively decreases the attenuation of
frequency selection caused by multi-path channel. Compared with other traditional
algorithms the signal to noise ratio is improved by 3 to 7 dB under the same bit error
rate.
Keywords:orthogonal frequency division multiplexing;channel estimation;least square
support
vector machine;time-varying channel
¡¡