Power Optimization for Joint Large Intelligent Surface - Amplify-and-Forward Relay in Full-duplex Communications.

Large Intelligent Surfaces are essential components in upcoming 6G networks due to their impressive capabilities and energy efficiency. To enhance network coverage, we introduce relays that can overcome distance and obstacle limitations. The focus is on integrating Large Intelligent Surfaces with amplify-and-forward relay techniques to facilitate communication between a base station and a full-duplex user, even in the presence of co-channel interference from device-to-device pairs nearby. To optimize data transmission, closed-form expression is derived that calculates the optimal power required to achieve maximum data rates while considering challenges like self-interference and co-channel interference from device-to-device communications. Also, quadratic transform for the non-convex problem is derived analytically to be able to solve the problem using CVX as well. Additionally, a neural network approach is proposed that accurately predicts the minimum power needed to achieve the maximum data rates. This neural network model proves to be a promising alternative with much less complexity.