Research On SC-FDMA Technology In LTE-Advanced Systems

After the third generation mobile communication, people are increasingly high demand for communication, compared with the traditional communications business, LTE projects have made a great breakthrough in higher data rates, increased system capacity, spectrum efficiency, enhance immunity, reduce business costs and other aspects, so it is with great research value. LTE-Advanced is an enhancement of LTE,with the further development and commercialization requirements of LTE project,in order to ensure the competitiveness of the LTE technology,3GPP began LTE-Advanced’s research work, and designate LTE-A as the4G technology preferred scheme.3GPP Working Group designate OFDM A technology as the downlink transmission scheme in the LTE standardization process,but for the uplink, because OFDMA limits the transmission power of communication equipments,and many independent modulation sub-carrier coherent used together, send signal has a high Peak to Average Power Ratio (PAPR), what’s more,high PAPR will seriously degrade the efficiency of the RF transmitter device power amplifier, increase the cost of the power amplifier, so it is not conducive to achieve in the uplink.In order to reduce the PAPR,LTE chose SC-FDMA technology, and LTE-A also retained it in the programs. This thesis studies the SC-FDMA technology and simulate its PAPR performance,the simulation results show that SC-FDMA system has lower PAPR than OFDMA system.Then the paper describes two different types of sub-carrier mapping schemes for SC-FDMA system:DFDMA and LFDMA,analyzes the characteristics of these two sub-carrier mapping schemes.In addition, analyzes SC-FDMA’s PAPR in different modulation mode and different filters. In order to reduce SC-FDMA’s PAPR,the article describes three kinds of amplitude limiting technologies to reduce PAPR, ultimately, proposed a improved PAPR reduction based on this, and the PAPR performance simulation proved the effect of amplitude limiting technology in PAPR reduction. In addition, the paper according to the traditional LS and MMSE channel estimation algorithm, estimated a simulation study based on the channel of the SC-FDMA system. In the end, the essay summarized the full text work,according to the difficulty point of SC-FDMA technology, the paper puts forward several improvement areas to prompted SC-FDMA technology more mature and perfect.