tely. The basic rule of NOMA is to unfollow the traditional orthogonality principle and adopts a new rule where users are served in a non-orthogonal manner. As the name suggests, NOMA serves multiple users using the same frequency and time. This implies that unlike any orthogonal multiple scheme, NOMA is capable of serving higher number of users in the available resource. Therefore, it is fair to say that NOMA will tackle spectrum crunch problem and at the same time will lead to massive connectivity. 5.2 Non-orthogonal Multiple Access A multiple access scheme by definition means a technique of serving multiple users over the same resource block by applying suitable rules such that the interference is minimum. Traditionally, this can be done by providing orthogonality in frequency, or time, or space, etc. It has been observed that with the advancement of wireless technology from the first generation (1G) of wireless network to the fourth generation of the wireless network, one major change in technology that has occurred is in the multiple access scheme adopted. For instance, 1G used an analog frequency modulation scheme known as frequency division multiple access. Further, the second generation used a digital modulation scheme called as time division multiple access (TDMA). The third generation shifted towards code division multiple access (CDMA), introduced by Qualcomm [9]. However, CDMA was unable to meet high data demands of the 4G networks; therefore, 4G adopted yet another advanced technique, the orthogonal frequency division multiple access (OFDMA) [10]. The orthogonal multiple access (OMA) techniques are widely accepted in the 4G and current 5G (NR2) standards [11, 12]. As the multiple access techniques have advanced from generation to generation, the fifth generation of the wireless networks requires even more advanced method to meet the requirements of massive users and make the system spectrally efficient. Under such circumstances, NOMA is seen as the potential multiple access scheme for the 5G networks