Tuyển tập báo cáo các nghiên cứu khoa học quốc tế ngành hóa học dành cho các bạn yêu hóa học tham khảo đề tài: Selected basis for PAR reduction in multi-user downlink scenarios using lattice-reduction-aided precoding | Siegl and Fischer EURASIP Journal on Advances in Signal Processing 2011 2011 17 http content 2011 1 17 o EURASIP Journal on Advances in Signal Processing a SpringerOpen Journal RESEARCH Open Access Selected basis for PAR reduction in multi-user downlink scenarios using lattice-reduction-aided precoding Christian Siegl and Robert FH Fischer Abstract The application of OFDM within a multi-user downlink scenario is considered. Thereby two problems occur. First due to OFDM the transmit signal exhibits a large peak-to-average power ratio PAR . Second the multi-user interferences have to be equalized or precoded at the transmitter side. In this article we address combined precoding and PAR reduction. As precoding schemes sorted Tomlinson-Harashima precoding sTHP and its latticereduction-aided variant LRA-THP are considered. In order to reduce the PAR we review the scheme selected sorting SLS which is a combined approach of PAR reduction and precoding with sTHP. Based on this idea the novel PAR reduction scheme selected basis SLB is introduced which combines PAR reduction with the precoding approach LRA-THP. It can be shown that SLB achieves very good PAR reduction performance and hardly influences the error performance. Both schemes SLB and SLS are compared with simplified selected mapping sSLM the only PAR reduction scheme from the SLM family which can be applied in multi-user downlink scenarios. The comparison is done on the basis that the respective schemes exhibit the same computational complexity. In terms of PAR reduction performance it turns out that sSLM outperforms SLS whereas the performance of sSLM and SLB is similar. Noteworthy the great benefit of SLB or SLS is that no side information has to be communicated to the receiver as it is necessary with sSLM. Moreover using SLB full diversity error rate performance is possible with only low-PAR transmit signals. Introduction Orthogonal frequency-division multiplexing OFDM 1 is a very .
