NON ORTHOGONAL MULTIPLE ACCECC (NOMA) USING MIMO SYSTEM

Abstract

Wireless broadcasting requires a single point to multipoint data communication from a single transmitter to multiple receivers. In present broadcasting models, the multiplexing of user information is done by using orthogonal multiple access (OMA) techniques in which time or frequency resources are divided for multiple receivers. Similar transmission for wireless braodcasting is non-orthogonal multiple access (NOMA), which superimposes user signals on top of each other at the transmitter with different power coefficients and use successive interference cancellation (SIC) at the receivers to decode the user-information. While OMA multiplexes users on the basis of frequency or time to make them orthogonal, NOMA multiplexes user in the power domain depending upon the distance of user from the transmitter in the cell. In Rayleigh fading channel with additive white Gaussian Noise (AWGN) wireless channels, NOMA provides better capacity gain than OMA at the cost of increased decoding complexity at the receivers of NOMA. In future when there will be huge numbers of devices connected to internet using wireless channels, NOMA doesn’t have edge due to the fact that when increasing the number of users in the cell, capacity gain don’t tend to increase very significantly. The performance gap decreases constantly when increasing the number of users in the cell. Therefore, NOMA is used with MIMO system as the solution of above problem