Analysis of the MU-MIMO System from the Perspective of Orthogonal and Non-Orthogonal Access

Many advanced technologies, including MIMO (Multiple Input Multiple Output) technology, have been proposed to achieve the data rates defined by today's wireless standards and to improve spectral efficiency. With this technology, multiple users were allowed to use the same spectrum. MU-MIMO stands for multi-user and represents a significant advance over single-user MIMO. Multiple access technologies can be divided into orthogonal and non-orthogonal methods. NOMA (Non-Orthogonal Multiple Access) technology currently includes many varieties and classifications and the only criterion by which a variety of multiple access technologies is classified as NOMA is that it is not an orthogonal multiple access technology. Also with the development of MIMO technology, it is possible to use spatial resources to organize multiple access. This paper shows that a communication system with MU-MIMO technology can also be considered as a NOMA system.