Survey and Comparison of MIMO and Massive MIMO Evolution for 5G and 6G

The emerging fifth-generation (5G) and sixth-generation (6G) technologies require highly efficient wireless communication systems. For this purpose, Multiple-Input Multiple-Output (MIMO) technology is a foundational component. However, conventional MIMO faces challenges in scalability and interference management, often limiting its use to smaller-scale applications. This work positions Massive MIMO as the solution, which utilizes a very large number of antennas at the base station. This architecture dramatically improves capacity, spectral efficiency, and energy efficiency by serving many users simultaneously through precise spatial multiplexing. A detailed comparison between conventional MIMO and Massive MIMO is presented. The comparative metrics analyzed include spectral efficiency, energy efficiency, scalability, user density, and channel state information (CSI) estimation. The analysis confirms that Massive MIMO offers superior performance compared to traditional MIMO technology. Furthermore, we explore the integration of Massive MIMO with advanced technologies such as artificial intelligence (AI), intelligent reflecting surfaces (IRS), and terahertz (THz) communication. Among these, the synergy between Massive MIMO and AI is identified as a particularly promising approach for enabling robust and efficient future wireless communication.