| 3GPP LTE-Advanced as long term evolution(LTE)improved, reached higher technical requirments. It can provide high bandwidth, high rate, reduce the delay and the operation cost; also can achieve a core network which supports multiple access technology, based on the IP packet. LTE-Advanced system uplink multiple-access technology is SC-FDMA(Signal Carrier-Frequency Division Multiple Access) technology which is based on lower PAPR(Peak to Average Power Ratio). The main research of this paper is the carrier synchronization algorithm for LTE-Advanced uplink MIMO SC-FDMA system.In a wireless communication system, due to the transmitting frequency and the receiving frequency are not entirely consistent, a frequency offset will occur, at the same time, relative motion between the transmitting end and the receiving end can also generate a Doppler frequency shift. But the MIMO SC-FDMA system is relatively sensitive to carrier frequency offset (CFO), when the carrier frequency offset is present, it will not only destroy the orthogonality among subcarriers to cause inter-carrier interference and multiple access interference, but also can make the information cannot be recovered correctly, increase the bit error rate, and finally will influence the performance of the system.Detection algorithm is an effective algorithm to eliminate the interference of the signal, in MIMO system, through detecting the target signal and the interference signal data to make them separate, and eliminating the interference among the signals at the meantime. The strong similarity between wireless MIMO transmission link model and CDMA system, the ISI channel, can extend the basic principle of some detection algorithms in CDMA system and ISI channel to the signal detection in wireless MIMO transmission link, the signal can be separated, interference can be eliminated.According to MIMO SC-FDMA system is very sensitive to carrier frequency offset, a carrier synchronization algorithm based on the OSIC method is proposed in this paper. The algorithm is based on successive interference cancellation (SIC) mechanism, the carrier frequency offset (CFO) signals are sorted, filtering and interference elimination, each signal can also be separated by iterative equalization. In each detection process, certain criteria is selected to choose the signal which should have the maximum SNR(signal-to-noise ratio) or SIR(signal-to-interference ratio)to be detected. After the current signal is being detected, it will be eliminated as the interference from the received signal, then another signal will be detected. This process will not be terminated until all the signals being detected. This method not only separates the transmitted signals being required, but also reduces the bit error rate, and improves the performance of the system. |
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