In order to provide high data rates, band width, reduced error rates, spectral efficiency, and low latency, a mobile system that is integrated into both non-orthogonal multiple access (NOMA) and orthogonal frequency division multiplexing (OFDM) schemes simultaneously is needed. The 5G system uses multi-carrier transmission systems, multiple access structures, and channel coding techniques to fulfill the demands. There are different modulation techniques for the 5G system beyond OFDM, such as filter bank multicarrier (FBMC), universal filtered multicarrier (UFMC), and general frequency division multiplexing (GFDM). In OFDM, the samples of the multicarrier modulation signal can be generated by the IFFT/FFT operation rather than employing extra modulation and demodulation techniques. Due to this OFDM is attractive compared to other multicarrier modulations and compatible with NOMA systems. In this thesis, LDPC-coded OFDM-NOMA systems are used. The system achievable capacity and error performance are studied using simulation with Matlab software. The error performance of coded OFDM-NOMA using LDPC code and uncoded OFDM-NOMA is evaluated. The obtained results show that to reach the same BER value,the LDPCcoded system requires a very low SNR value,whereas in the uncoded system is very high. There is an error floor in the LDPC code in a region around BER of 10 −5 . The error performance of the near and far users is also compared with the LDPC code. The obtained results show that the near user used the highest SNR to reach the error-floor region of the LDPC code, whereas the far user uses a low SNR. Far user has better BER performance than near user because near user has to decode both near and far users for SIC. The capacity comparison of the near user and the far user is also done. The result shows that the capacity of the far user is lower than that of the near user. In addition capacity comparsion of NOMA-OFDM and OFDM-OMA are analyzed. The results shows that NOMA-OFDM has a higher capacity than OFDM-OMA. Key Words: 5G,LDPC Code, NOMA, OFDM