Interference Suppression via Joint Interference Alignment and Power Allocation in Integrated Communication and Navigation Systems

This paper addresses the complex interference in integrated communication and navigation (ICAN) systems by proposing an interference suppression scheme that integrates interference alignment (IA) with power allocation (PA). In the proposed scheme, the IA algorithm first mitigates inter-satellite and intra-satellite beam interference by aligning interference signals into a common subspace. These signals are then eliminated through the design of beam precoding vectors and integrated user detection vectors. For intra-beam interference, we formulate a PA-based optimization problem to maximize the system sum rate. This problem is decoupled into per-beam sum rate maximization. By reformulating the user minimum rate constraints, the original problem is further transformed into a convex optimization problem. The optimal solution is derived using the Karush-Kuhn-Tucker (KKT) conditions from convex optimization theory. Simulation results demonstrate the effectiveness of the proposed interference suppression scheme.