| 4G will integrate various functions and applications that need high data rate and efficient bandwidth schemes. Not only does it increase system's capability, but also it can meet the demand of multimedia communication. It can transmit multimedia traffic at high quality including voice, data, voice through wide-frequency channel. But bandwidth is limited, one promised solution is to employ Multicarrier Code Division Multiple Access (MC-CDMA) technique.MC-CDMA system is based on the combination of Orthogonal Frequency Division Multiplexing (OFDM) and Code Division Multiple Access (CDMA) technologies. Due to the use of a large number of carriers, MC-CDMA system is very sensitive to synchronization errors including timing synchronization error and frequency synchronization error.In this thesis, first, we describe the ideal MC-CDMA synchronization and the error MC-CDMA synchronization systems. Then, through simulating the timing recovery and carrier frequency offset correction of Non Data-Aided scheme based on cyclic prefix and Data-Aided synchronization scheme based on pilot symbols respectively, we show that the former can enhance system performance.Finally, we propose a new scheme based on cyclic prefix: firstly, frame synchronization and the fractional part of frequency offset are performed by an improved cyclic prefix; Secondly, symbol synchronization is corrected in time-domain based on received data stream and the sequence which is generated by IFFT of spreading code; Thirdly, the integer part of carrier frequency offset is performed by spreading code in frequency-domain. The result shows that new scheme can obtain better performance and reduce the complexity of system. |
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