Comparison Peak-to-average Power Ratio Of Single Carrier Fdma And Ofdma

In today's 3rd generation (3G) communications systems, we need to meet the 4th generation (4G) systems. 3rd Generation Partnership Project (3GPP) has released the Long Term Evolution (LTE) specification. Some of these changes are in the physical layer (PHY), In particular in the modulation and multiple access schemes. The generation relied on variations of Code Division Multiple Access (CDMA), However LTE implements Orthogonal Frequency Division Multiplexing (OFDM) for its downlink and for uplink it implements Single-Carrier Frequency-Division Multiple Access (SC-FDMA). In this project I investigating the reasoning for this discord between uplink and downlink modulation schemes; in particular, why Orthogonal Frequency Division Multiple-Access (OFDMA) was not used as the uplink. OFDMA and SC-FDMA are the multiple-access versions of OFDM which has similar modulation scheme, Single-Carrier Frequency-Domain Equalization (SC-FDE). In this project the differences between the multiple-access methods is compared , firstly cover the differences between their underlying modulation schemes is covered ,secondly covers these differences, building the foundation for a comparison between the multiple-access methods themselves which thirdly will lead us to the bases used for comparison of peak-to-average power ratio (PAPR). PAPR is main important for the uplink of mobile devices. It is important to keep a low PAPR on the uplink to reduce drain batteries on mobile devices more quickly. In this project i analyze the PAPR of SC-FDMA and analytically derive the time domain SC-FDMA signals and numerically compare PAPR characteristics using the complementary cumulative distribution function (CCDF) of PAPR. And from the result 1 will find which has lower PAPR between OFDAM and SCFDMA. Comparing the two forms of SC-FDMA,I have to find which has higher PAPR between localized FDMA (LFDMA) and interleaved FDMA (IFDMA) In Conclusion I analyze the PAPR of SC-FDMA signals and compare it with the case of OFDMA deriving the time domain signals of IFDMA and LFDMA, and numerically compare PAPR characteristics using CCDF of PAPR and show which signals indeed have lower PAPR compared SC-FDMA and OFDMA and also show which Incurs higher PAPR compared to IFDMA and LFDMA. During simulation will see how raised cosine pulse shaping will affect PAPR using QPSK and 16 QAM modulations, with different roll off factor.