Peak power analysis of MC-CDMA employing Golay complementary sequences

Abstract

l\!Iulticarrier code division multiple access (MC-CDMA) combines both orthogonal frequency division multiplexing (OFDM) and code division multiple access (CD lVIA) techniques. It inherits the advantages of these two techniques. However, like the OFDM system, transmitted signal of rv1C-CDl'v1A system suffers from the high peakto- average power ratio (PAPR) as well. As a good solution to reduce the high peak-to-average pmver ratio (PAPR), Golay complementary sequences have been employed in multicarrier communication systems. In this thesis, we present a simple but novel technique to analyse the theoretical PAPR bounds of downlink l'v1C-CDMA system using Golay complementary sequences for spreading and/ or coding. \Ve first develop the PAPR bounds of uncoded IVIC-CDMA system using binary Golay complementary spreading sequences. Then, we develop the PAPR b ounds when each user's transmitted data is encoded as QPSK Golay sequences or 16- QAI'vl Golay sequences. Simulation results demonstrate that the theoretical PAP R bounds and 99.9% PAPRs are independent of the spreading factor for uncoded case. For coded case , the theoretical PAPR bounds and 99.9% PAPRs are independent of the number of spreading processes as well as the spreading factor. Practically, the independency shows that G olay complementary sequences are useful for peak povver control in downlink MC-CDMA system.