In the recent decade the multi-carrier modulation is considered by wireless system designers due to its high data rate and resistance against multipath fading effects. Orthogonal frequency division multiplexing (OFDM) is widely known and is the most commonly used multi-carrier modulation scheme in many communication standards. Also, OFDM is generalized for use in multi-user systems and is called orthogonal frequency division multiple access (OFDMA). Two important applications of OFDMA are in WiMAX and LTE uplink. Despite the advantages, OFDMA systems have two major challenges. First is high peek to average power ratio (PAPR), that results in coverage reduction and non-linear signal amplification that decrease bandwidth efficiency. High PAPR requires high-power amplifier with very large dynamic range, which results in increased system cost. By adding a discrete Fourier transform (DFT) pre-coder to OFDMA transmitter, PAPR will be reduced significantly. The amount of PAPR in this scheme, which is called single carrier frequency division multiple access (SC-FDMA), depends on subcarrier allocation scheme. In the interleaved allocation scheme, uniformly distributed subcarriers in the available bandwidth are assigned to each user, and this results in the least amount of PAPR. Therefore in the LTE uplink the SC-FDMA is used to improve power characteristics. The second challenge of OFDMA based systems is sensitivity to carrier frequency offsets (CFO). The CFO is caused by instability of local oscillators and Doppler effect. Due to synchronization errors in time-varying channels, it is not possible to remove CFO completely. The effect of CFO on OFDM signal is the interference between subcarriers. In uplink transmission the CFO causes interference between different user subcarriers called multiple access interference (MAI), which significantly reduces system performance. There are several proposed techniques to compensate CFO effects in OFDMA and SC-FDMA systems and their common challenge is high computational complexity. This thesis is focused on CFO problems in SC-FDMA systems and comparison of different CFO compensation techniques. An interleaved SC-FDMA system, that has highest frequency diversity and lowest PAPR compared to other allocation schemes, is considered and a new low complexity technique is proposed to compensate CFO. The proposed scheme compensates CFO by the goal of maximizing the average signal to interference power ratio (SIR). It shows better performance compared to other techniques with comparable complexity. To further improve performance, a simple algorithm is proposed to remove MAI after CFO compensation. The proposed technique provides a suitable performance with very low complexity. Also despite other methods, this technique shows good stability in systems with imperfect power control. Keywords: SC-FDMA system; carrier frequency offset; CFO compensation; inter carrier interference; multiple access interference; interference cancellation algorithms.