NOMA (Non-Orthogonal Multiple Access) has potential to improve spectral efficiency and provide solution to higher multi-user connectivity with higher sum data rate for 5G and beyond. Therefore, NOMA was also included in the 3GPP LTE-A Release-13.The central idea of NOMA is to separate the user in power-domain. In comparison to previous orthogonal multiple access technique which faces spectrum crunch, like, SC-FDMA and OFDM, more time-frequency resource make available to all user in NOMA, enabling high-data rate, low latency, and high reliability. The Key operation in NOMA is use of superposition coding (SC) at transmit side and successive interference cancellation (SIC) at receiver.