Research On Channel Estimation Of Long Term Evolution Uplink

Broadband wireless mobile communications suffer from multi-path frequency selective fading. Orthogonal Frequency Division Multiplexing (OFDM), which is multi-carrier communication techniques, has become widely accepted primarily because of its robustness against frequency selective fading channels. However, OFDM suffer a number of drawbacks such as high peak-to-average power ratio (PAPR), a need for an adaptive or coded scheme to overcome spectral nulls in the channel, high sensitivity to frequency offset and so forth. High PAPR requires high linearity of the high frequency power amplifier, and leads to low power efficiency. On the other side, Single Carrier with Frequency Domain Equalization (SC/FDE) is also robust against frequency selective fading but the PAPR property is more preferable.Single Carrier Frequency Division Multiplexing Access (SC-FDMA) is the combination of OFDM and SC/FDE, which utilizes single carrier modulation at the transmitter and frequency domain equalization at the receiver. SC-FDMA has the similar performance and essentially the same overall structure as those of an OFDMA system. One prominent advantage over OFDMA is that the SC-FDMA signal has lower PAPR, which will greatly benefits the mobile terminal in terms of transmission power efficiency and manufacturing cost. SC-FDMA is selected as the uplink multiple access scheme in 3rd Generation Partnership Project Long Term Evolution (3GPP LTE).This thesis mainly investigates on the channel estimation of the LTE uplink based on the SC-FDMA. At first, given the transmission characteristics of cellular radio channel, and given the comparison of advantages and disadvantages between OFDM and SC/FDE system. Then come up with the SC-FDMA transmission technology and analysis its system architecture, sub-carrier mapping, time domain expression and signal characteristics. Study the characteristic of PAPR in different subcarrier mapping and different filter in the transimitter. Investigate the characteristic of Channel Depending Schedule of SC-FDMA in different subcarrier mapping. A simulation on the system performance of channel estimation of SC-FDMA system is been made. On this basis, proposed a pilot signal transform domain approach, the simulation analysis concludes that using this method can considerably improved the system performance.