The principal challenge encountered in any high-speed digital communication architecture is the optimization of the data transmission rate while concurrently minimizing the bit error rate. Numerous methodologies have been devised to attain this objective. The fundamental components of Long-Term Evolution (LTE) include Single Carrier Frequency Division Multiple Access (SC-FDMA) and Orthogonal Frequency Division Multiple Access (OFDMA). OFDMA is employed in the LTE downlink as a multiple access technique, as it offers substantial bandwidth efficiency, resilience to multipath interference and frequency-selective fading, along with simpler equalization requirements at the receiver end. SC-FDMA has been introduced relatively recently and has emerged as a viable candidate for the uplink multiple access framework in LTE systems due to its advantage of reduced Peak-to-Average Power Ratio (PAPR) in comparison to OFDMA. In this study, we conducted an analysis of the performance characteristics of SC-FDMA and OFDMA within the LTE framework, utilizing various modulation techniques (BPSK, QPSK, 16QAM, and 64QAM) based on parameters such as PAPR, Bit Error Rate (BER), and error probability, by simulating the models of SC-FDMA and OFDMA. We employed an Additive White Gaussian Noise (AWGN) channel and incorporated frequency flat fading within the channel through the application of a Rayleigh fading model to assess performance in the presence of both noise and fading phenomena.................... Keywords:............. OFDMA, SC-FDMA, BER, PAPR, LTE.