Simulation Research And DSP Implementation Of Single Carrier Frequency Division Multiple Access System

With the continuously developing of wireless communication technique and the users’ high demands to communication,3GPP proposed LTE (Long Term Evolution) standard as the transition from3G to4G. While LTE downlink adopts orthogonal-frequency-division-multiplexing access (OFDMA) technique, OFDMA is not suitable for LTE uplink because of its disadvantages. The first main disadvantage is that OFDM signal’s peak-to-average power ratio (PAPR) is very high, which decreases the power efficiency of mobile terminal and proposes higher demands on the linearity of transmitter power amplifier, which will increase the cost of transmitter. Secondly, OFDMA requires strict orthogonality among sub-carriers, which makes it sensitive to frequency offset. Single-carrier frequency-division multiple-access (SC-FDMA) technique is the combination of OFDMA and SC-FDE techniques. Possessing the similar structure and performance as OFDMA, SC-FDMA shows the advantage of lower PAPR feature and being not sensitive to frequency offset. Besides, SC-FDMA can adopt frequency equalization technique at the receiver to overcome the influence of multi-path fading. So,3GPP decided to adopt SC-FDMA to be the multiple access technique in the LTE uplink.This thesis focuses on the research of channel estimation and frequency equalization techniques of LTE uplink SC-FDMA link-level system, which are the key point of receiving techniques. Firstly, the SC-FDMA system principle, sub-carrier mapping and LTE uplink frame structure are elaborated in the thesis, which verified that the SC-FDMA has the advantage of lower PAPR compared to OFDMA. Then, the thesis introduces the pilot structure of LTE uplink frame structure, on the basis of which, the theoretical of channel estimation algorithms such as LS, LMMSE and SVD-MMSE and the frequency equalization algorithms such as ZF and MMSE are studied. The SC-FDMA link-level simulation platform is built and the algorithm performance are evaluated through the statistic results of the the mean square error and bit error ratio.The final part is another important content of the thesis, in which the SC-FDMA link-level system is implemented on the software radio platform BS200, including realized LS channel estimation and ZF frequency equalization at the receiver. The thesis introduces the software architecture of SC-FDMA system implemented on the three cores DSP chip TMS320C6474, as well as the process schedule of each core and some details of the implementation. Last, a host computer program is developed to test the bit error ratio of the SC-FDMA system which is implemented on DSP.