Advantages and Challenges of Applying Nonlinear Optimization Techniques in 6G Systems

The commercial deployment of the fifth-generation mobile communications system (5G) is progressing, and applications and user experiences are gradually evolving. In wireless communications, the technologies must be applied to guarantee high-quality transmission in spite of propagation channel fluctuations. Taking linear equalization as an example, in this paper, several signal processing technologies that support 5G are introduced and the characteristics of linear and nonlinear signal processing methods are described. It is shown that the linear and nonlinear signal processing methods reduce computational complexity and improve system performance, respectively. The characteristics of 5G standardization trends are also introduced, the situations in which use cases of use are subdivided and added are described, and the concept of cell-free systems, which is the system model of 6G, the next generation of 5G, is presented. In 6G, the number of elements in communication resources allocation will increase exponentially, and multiple objective functions will also arise. We describe how to quickly derive a quasi-optimal solution using machine learning while separating and integrating interference, and how to control the 6G system, including wireless resources. This makes it possible to accommodate future expansions of super-use cases that cover all applications, areas, and communication styles.