04622nas|a2200445 i 4500 20260818144334.0 300501s2000 th uzm rtt 00| a1eng d .b1182699x AIT Thesis no.TC-00-06 Nanthawan Ruangsurat An investigation of peak to average power ratio in MC-CDMA combined with partial transmit sequence Bangkok : Asian Institute of Technology, 2000 72 p. Thesis ; no. TC-00-06 A thesis submitted in partial fulfillment of the requirements for the degree of Master of Engineering, School of Engineering and Technology Thesis (M.Eng.) - Asian Institute of Technology, 2000 Multicarrier code division multiple access (MC-CDMA) is a technique that combines orthogonal frequency division multiplexing (OFDM) and code division multiple access (CDMA). Since MC-CDMA system provides an efficient method of frequency diversity, it is suitable to a frequency selective rayleigh fading environment. This technique becomes a potential technique for future wireless networks. In addition, MC-CDMA is especially useful in the downlink transmission. However, similar to OFDM system, the transmitted signal from MC-CDMA system also exhibits a very high Peak to Average Power Ratio (PAPR) when using a large number of subcarriers. Therefore, the amplifiers should be operated in large linear ranges to avoid nonlinear distortion. This leads to very inefficient amplification and very expensive transmitters. Thus, P APR reduction techniques are very significant for multicarrier transmission systems. Consequently, several P APR reduction methods have been proposed, but most of techniques are considered with single user OFDM such as Clipping, Selected Mapping, Partial Transmit Sequence, and so on. In MC-CDMA systems, the P APR reduction technique is mostly based on the type of spreading sequences. Partial Transmit Sequence (PTS) technique is an efficient approach and a distortionless scheme for reducing P APR. Due to its flexibility, the PTS technique works with an arbitrary number of subcarriers. In addition, it works without restriction on the type of modulation scheme. Thus, the investigation of P APR in MC-CDMA system combined with PTS technique is very attractive. In this thesis, the P APR reduction in synchronous downlink MC-CDMA using PTS technique is investigated with a different number of active users. Moreover, WalshHadamard (WH) sequence and Orthogonal Gold (OG) sequence are used as the spreading sequences in MC-CDMA system. From the simulation results, when the number of active users is varied, P APR reduction of this system also varies depending on the P APR characteristics of spreading sequence. Although PTS technique is very efficient in reducing PAPR, high PAPR reduction is achieved at a cost of increased system complexity. Furthermore, to compromise between P APR reduction and system complexity, the suboptimal algorithms are used for combining partial transmit sequences. Based on simulation results, we can reduce system complexity by more than 90% at the expense of little P APR performance degradation. Code division multiple access Rajatheva, R.M.A.P, Chairperson Erke, Tapio J., Examination Committee Teerapat Sanguankotchakorn, Examination Committee Nokia Telecommunications (Thailand) Ltd., Scholarship Donor Asian Institute of Technology. Thesis ; no. TC-00-06 Full-Text http://203.159.5.9/ait-thesis/detail.php?q=B06530 .b1182699x mnait u 240710 0 010530 m a u 3 mnait mnait mnarc mnarc 22 40 20 Barcode : 30050120808091 CREATED : 2014-10-04 RECORD # : i12789665 LPATRON : 0 LCHKIN : - # RENEWALS : 0 # OVERDUE : 0 IUSE3 : 0 TOT CHKOUT : 0 TOT RENEW : 0 Barcode : 30050160045349 CREATED : 2016-02-03 RECORD # : i12888369 LPATRON : 0 LCHKIN : - # RENEWALS : 0 # OVERDUE : 0 IUSE3 : 0 TOT CHKOUT : 0 TOT RENEW : 0 Barcode : 30050211033790 CREATED : 2021-06-05 RECORD # : i13345412 LPATRON : 0 LCHKIN : - # RENEWALS : 0 # OVERDUE : 0 IUSE3 : 0 TOT CHKOUT : 0 TOT RENEW : 0 Barcode : 30050211026744 CREATED : 2022-12-01 RECORD # : i13358200 LPATRON : 0 LCHKIN : - # RENEWALS : 0 # OVERDUE : 0 IUSE3 : 0 TOT CHKOUT : 0 TOT RENEW : 0 64758 64758 0 0 0 0 MAIN MAIN mnarc 2026-08-18 50.00 0 AIT Thesis no.TC-00-06 30050120808091 2026-08-18 14:43:34 3 2026-08-18 22 0 0 0 0 MAIN MAIN mnarc 2026-08-18 0 AIT Thesis no.TC-00-06 30050160045349 2026-08-18 14:43:34 2026-08-18 40 0 0 0 0 MAIN MAIN mnait 2026-08-18 50.00 0 AIT Thesis no.TC-00-06 30050211033790 2026-08-18 14:43:34 1 2026-08-18 20 0 0 0 0 MAIN MAIN mnait 2026-08-18 50.00 0 AIT Thesis no.TC-00-06 30050211026744 2026-08-18 14:43:34 2 2026-08-18 20