PAPR Reduction And CDS In SC-FDMA System

The LTE project plays an important role between the third generation mobilecommunication and the fourth generation mobile communication. In order to keep theadvantages of the technology and standard in the field of communication, the LTE hasbegun to work on the project since2004. The target of the LTE is to realize the lowercost， higher data transmission rate， more efficient utilization of spectrum andbackward compatibility and so on, which puts forward further requirements to thephysical layer transmission technology. The SC-FDMA takes advantage of the lowPAPR, and it becomes the physical transmission scheme in the LTE unlink system.This thesis begins with an introduction of the development of the background, thestatus of current research and the importance of the research. It also has a detaileddescription of the basic principles. Under the different condition of sub-carriermapping，we compare the PAPR of interleaved frequency division multiple access,distributed frequency division multiple access and localized frequency divisionmultiple access.The main work of this thesis is studying PAPR reduction and CDS in SC-FDMAsystem. We proposed selective mapping, statistical companding method can effectivelyreduce the PAPR in SC-FDMA system. It not only improves efficiency of poweramplifier, but also extends the coverage of the SC-FDMA system without degradingthe link performance. The simulation results show that the PAPR of SC-FDMA systemis lower than that of OFDMA system, SC-FDMA is more suitable as a physical layertransmission scheme in uplink system. We investigate channel-dependent schedulingfor SC-FDMA system. We analyze the capacity gains for the two different methods ofsubcarrier mapping of SC-FDMA, and we also look into the impact of imperfectchannel state information CDS by considering the CSI feedback delay. It shows thatlocalized subcarrier allocation yields the highest data throughput for slow fadingchannel, and distributed subcarrier mapping with static round-robin scheduling is moresuitable for fast fading channel.