Study On Key Techniques For Multi-Carrier CDMA System

MC-CDMA is an integrated technology of OFDM and CDMA. This technology is considered as the core technology of the future 4G wireless communications, because it kept the advantages of OFDM and CDMA, and can be used for multimedia data transmission. So the superior characteristics of MC-CDMA in wireless communication are demonstrated by comparing the BER performance of OFDM system and MC-CDMA system. Based on these simulations, the thesis studies the channel estimation problem with comb pilot.First, the fundamental principles of OFDM technology and three schemes of OFDM-CDMA are introduced. Then MC-CDMA is proposed to be the object of the study. MC-CDMA can be the reference for the practical usage of OFDM-CDMA.Then, based on OFDM and MC-CDMA system models which are simulated with MATLAB, the simulation charts of the BER performances comparing between OFDM and MC-CDMA system from combating the White Gaussian Noise and Multi-path Interference are given. From analyses of the charts, MC-CDMA system is concluded to be superior to OFDM in the wireless data transmission.Last is investigation on the problem of pilot-assisted channel estimation with comb pilot in downlink MC-CDMA. Channel estimation is divided into LS estimation at pilot tones and the interpolation of the preliminary estimate. The thesis improves the algorithm based on FFT , then through the simulation of different interpolation methods it proves the improved algorithm is better.