Simulation and Research on SC-FDMA in LTE Uplink
|School||Southwest Jiaotong University|
|Course||Communication and Information System|
|Keywords||LTE SC-FDMA SC-FDE OFDM OFDMA PAPR|
To meet the demands of the mobile communications market, and compete with emerging technologies, such as WiMAX and Wi-Fi, at the end of 2004 the 3rd Generation Partnership Project(3GPP) has proposed the 3G long term evolution(3G LTE), which is evoluted from the 3rd Generation system. The LTE technology will provide higher data rates, lower latency and better quality of service.Finally single carrier frequency division multiple access(SC-FDMA) has been adopted for uplink transmission in technology standardized for LTE, which utilizes single modulation, orthogonal frequency division multiplexing and frequency domain equalization. One prominent advantage over OFDM is that the SC-FDMA signal has lower PAPR because of its inherent single carrier structure. The main purpose of this thesis is to provide simulation researches on SC-FDMA using Matlab in physical layer, which integrates related communication technologies.The major research work is reflected in the following three parts. In the first part, the technologies of OFDM and SC-FDE and the two important algorithms of frequency domain equalization are introduced first. Then considering three type channel model and two linear equalizations, OFDM system and SC-FDE system are simulated to compare the BER performance. The second part recommends SC-FDMA system model, subcarrier mapping and frame structure first. Then the simulation of SER performance comparison of IFDMA, LFDMA and DFDMA are provided. Simulation results show that signals’starting symbol occupying different positions on subcarriers influence the BER performance of signals, and so IFDMA’ starting symbol occupying the first subcarrier has the best performane. The contrast of SC-FDMA system and SC-FDE system on SER performances in different channel environmens and different equalization algorithms is given next. Although both the two system conclude single carrier transmition, SC-FDMA has a better performance in the multiple path channel. The primary objective of the third section is the PAPR issue for SC-FDMA, where the definition and characteristic of PAPR are introduced first. The PAPR performances of SC-FDMA signals in different modulation mode are simulated and analyzed by adjusting the pluse shaping filter roll-off factor and numbers of system subcarriers. At the same time, the PAPR performance of OFDMA system is compared. Simulation results show that with the increase of filter roll-off factor, the PAPR of SC-FDMA system will reduce; with the increase of numbers of system subcarriers, the PAPR of SC-FDMA system will increase. On the whole, SC-FDMA system has lower PAPR than OFDMA system.