Performance of SC-FDMA for LTE Uplink Under Different Modulation Schemes

Single-carrier frequency division multiple access (SC-FDMA) is common choice for uplink of long term evolution (LTE) standard for broadband wireless communication. SC-FDMA is preferred for LTE uplink mainly due to its advantage of having low peak-to-average power ratio (PAPR) during signal transmission. The performance of SC-FDMA depends on modulation scheme used for it. In this paper performance of SC-FDMA for LTE uplink is compared on the basis of symbol error rate (SER) using different types of modulation schemes, like, binary phase shift keying (BPSK), quadrature phase shift keying (QPSK) and quadrature amplitude modulation (QAM). Also the performance of SC-FDMA is compared with orthogonal frequency division multiplexing (OFDM). In this paper, mainly variation of symbol error rate (SER) with signal-to-noise ratio (SNR) is investigated. It is found that by increasing spreading factor symbol error rate is reduced for SC-FDMA system and for spreading factor of 64 for SNR=20 dB, SER is of the order of 10^-4. A comparison of SER for SC-FDMA system with BPSK, QPSK, 16-QAM and 64-QAM shows that BPSK has lowest SER. When compared between localized and distributed mappings for SC-FDMA and OFDM, it is found that localized schemes have lower SER for both the cases than distributed scheme.